Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Completely Fair Scheduling (CFS) Class (SCHED_NORMAL/SCHED_BATCH) |
| 3 | * |
| 4 | * Copyright (C) 2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
| 5 | * |
| 6 | * Interactivity improvements by Mike Galbraith |
| 7 | * (C) 2007 Mike Galbraith <efault@gmx.de> |
| 8 | * |
| 9 | * Various enhancements by Dmitry Adamushko. |
| 10 | * (C) 2007 Dmitry Adamushko <dmitry.adamushko@gmail.com> |
| 11 | * |
| 12 | * Group scheduling enhancements by Srivatsa Vaddagiri |
| 13 | * Copyright IBM Corporation, 2007 |
| 14 | * Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> |
| 15 | * |
| 16 | * Scaled math optimizations by Thomas Gleixner |
| 17 | * Copyright (C) 2007, Thomas Gleixner <tglx@linutronix.de> |
Peter Zijlstra | 2180508 | 2007-08-25 18:41:53 +0200 | [diff] [blame] | 18 | * |
| 19 | * Adaptive scheduling granularity, math enhancements by Peter Zijlstra |
| 20 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 21 | */ |
| 22 | |
Arjan van de Ven | 9745512 | 2008-01-25 21:08:34 +0100 | [diff] [blame] | 23 | #include <linux/latencytop.h> |
Christian Ehrhardt | 1983a92 | 2009-11-30 12:16:47 +0100 | [diff] [blame] | 24 | #include <linux/sched.h> |
Sisir Koppaka | 3436ae1 | 2011-03-26 18:22:55 +0530 | [diff] [blame] | 25 | #include <linux/cpumask.h> |
Nicolas Pitre | 83a0a96 | 2014-09-04 11:32:10 -0400 | [diff] [blame] | 26 | #include <linux/cpuidle.h> |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 27 | #include <linux/slab.h> |
| 28 | #include <linux/profile.h> |
| 29 | #include <linux/interrupt.h> |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 30 | #include <linux/mempolicy.h> |
Mel Gorman | e14808b | 2012-11-19 10:59:15 +0000 | [diff] [blame] | 31 | #include <linux/migrate.h> |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 32 | #include <linux/task_work.h> |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 33 | |
| 34 | #include <trace/events/sched.h> |
| 35 | |
| 36 | #include "sched.h" |
Arjan van de Ven | 9745512 | 2008-01-25 21:08:34 +0100 | [diff] [blame] | 37 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 38 | /* |
Peter Zijlstra | 2180508 | 2007-08-25 18:41:53 +0200 | [diff] [blame] | 39 | * Targeted preemption latency for CPU-bound tasks: |
Takuya Yoshikawa | 864616e | 2010-10-14 16:09:13 +0900 | [diff] [blame] | 40 | * (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 41 | * |
Peter Zijlstra | 2180508 | 2007-08-25 18:41:53 +0200 | [diff] [blame] | 42 | * NOTE: this latency value is not the same as the concept of |
Ingo Molnar | d274a4c | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 43 | * 'timeslice length' - timeslices in CFS are of variable length |
| 44 | * and have no persistent notion like in traditional, time-slice |
| 45 | * based scheduling concepts. |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 46 | * |
Ingo Molnar | d274a4c | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 47 | * (to see the precise effective timeslice length of your workload, |
| 48 | * run vmstat and monitor the context-switches (cs) field) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 49 | */ |
Mike Galbraith | 2140692 | 2010-03-11 17:17:15 +0100 | [diff] [blame] | 50 | unsigned int sysctl_sched_latency = 6000000ULL; |
| 51 | unsigned int normalized_sysctl_sched_latency = 6000000ULL; |
Ingo Molnar | 2bd8e6d | 2007-10-15 17:00:02 +0200 | [diff] [blame] | 52 | |
| 53 | /* |
Christian Ehrhardt | 1983a92 | 2009-11-30 12:16:47 +0100 | [diff] [blame] | 54 | * The initial- and re-scaling of tunables is configurable |
| 55 | * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus)) |
| 56 | * |
| 57 | * Options are: |
| 58 | * SCHED_TUNABLESCALING_NONE - unscaled, always *1 |
| 59 | * SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus) |
| 60 | * SCHED_TUNABLESCALING_LINEAR - scaled linear, *ncpus |
| 61 | */ |
| 62 | enum sched_tunable_scaling sysctl_sched_tunable_scaling |
| 63 | = SCHED_TUNABLESCALING_LOG; |
| 64 | |
| 65 | /* |
Peter Zijlstra | b2be5e9 | 2007-11-09 22:39:37 +0100 | [diff] [blame] | 66 | * Minimal preemption granularity for CPU-bound tasks: |
Takuya Yoshikawa | 864616e | 2010-10-14 16:09:13 +0900 | [diff] [blame] | 67 | * (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds) |
Peter Zijlstra | b2be5e9 | 2007-11-09 22:39:37 +0100 | [diff] [blame] | 68 | */ |
Ingo Molnar | 0bf377bb | 2010-09-12 08:14:52 +0200 | [diff] [blame] | 69 | unsigned int sysctl_sched_min_granularity = 750000ULL; |
| 70 | unsigned int normalized_sysctl_sched_min_granularity = 750000ULL; |
Peter Zijlstra | b2be5e9 | 2007-11-09 22:39:37 +0100 | [diff] [blame] | 71 | |
| 72 | /* |
| 73 | * is kept at sysctl_sched_latency / sysctl_sched_min_granularity |
| 74 | */ |
Ingo Molnar | 0bf377bb | 2010-09-12 08:14:52 +0200 | [diff] [blame] | 75 | static unsigned int sched_nr_latency = 8; |
Peter Zijlstra | b2be5e9 | 2007-11-09 22:39:37 +0100 | [diff] [blame] | 76 | |
| 77 | /* |
Mike Galbraith | 2bba22c | 2009-09-09 15:41:37 +0200 | [diff] [blame] | 78 | * After fork, child runs first. If set to 0 (default) then |
Ingo Molnar | 2bd8e6d | 2007-10-15 17:00:02 +0200 | [diff] [blame] | 79 | * parent will (try to) run first. |
| 80 | */ |
Mike Galbraith | 2bba22c | 2009-09-09 15:41:37 +0200 | [diff] [blame] | 81 | unsigned int sysctl_sched_child_runs_first __read_mostly; |
Peter Zijlstra | 2180508 | 2007-08-25 18:41:53 +0200 | [diff] [blame] | 82 | |
| 83 | /* |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 84 | * SCHED_OTHER wake-up granularity. |
Mike Galbraith | 172e082 | 2009-09-09 15:41:37 +0200 | [diff] [blame] | 85 | * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 86 | * |
| 87 | * This option delays the preemption effects of decoupled workloads |
| 88 | * and reduces their over-scheduling. Synchronous workloads will still |
| 89 | * have immediate wakeup/sleep latencies. |
| 90 | */ |
Mike Galbraith | 172e082 | 2009-09-09 15:41:37 +0200 | [diff] [blame] | 91 | unsigned int sysctl_sched_wakeup_granularity = 1000000UL; |
Christian Ehrhardt | 0bcdcf2 | 2009-11-30 12:16:46 +0100 | [diff] [blame] | 92 | unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 93 | |
Ingo Molnar | da84d96 | 2007-10-15 17:00:18 +0200 | [diff] [blame] | 94 | const_debug unsigned int sysctl_sched_migration_cost = 500000UL; |
| 95 | |
Paul Turner | a7a4f8a | 2010-11-15 15:47:06 -0800 | [diff] [blame] | 96 | /* |
| 97 | * The exponential sliding window over which load is averaged for shares |
| 98 | * distribution. |
| 99 | * (default: 10msec) |
| 100 | */ |
| 101 | unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL; |
| 102 | |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 103 | #ifdef CONFIG_CFS_BANDWIDTH |
| 104 | /* |
| 105 | * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool |
| 106 | * each time a cfs_rq requests quota. |
| 107 | * |
| 108 | * Note: in the case that the slice exceeds the runtime remaining (either due |
| 109 | * to consumption or the quota being specified to be smaller than the slice) |
| 110 | * we will always only issue the remaining available time. |
| 111 | * |
| 112 | * default: 5 msec, units: microseconds |
| 113 | */ |
| 114 | unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL; |
| 115 | #endif |
| 116 | |
Paul Gortmaker | 8527632 | 2013-04-19 15:10:50 -0400 | [diff] [blame] | 117 | static inline void update_load_add(struct load_weight *lw, unsigned long inc) |
| 118 | { |
| 119 | lw->weight += inc; |
| 120 | lw->inv_weight = 0; |
| 121 | } |
| 122 | |
| 123 | static inline void update_load_sub(struct load_weight *lw, unsigned long dec) |
| 124 | { |
| 125 | lw->weight -= dec; |
| 126 | lw->inv_weight = 0; |
| 127 | } |
| 128 | |
| 129 | static inline void update_load_set(struct load_weight *lw, unsigned long w) |
| 130 | { |
| 131 | lw->weight = w; |
| 132 | lw->inv_weight = 0; |
| 133 | } |
| 134 | |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 135 | /* |
| 136 | * Increase the granularity value when there are more CPUs, |
| 137 | * because with more CPUs the 'effective latency' as visible |
| 138 | * to users decreases. But the relationship is not linear, |
| 139 | * so pick a second-best guess by going with the log2 of the |
| 140 | * number of CPUs. |
| 141 | * |
| 142 | * This idea comes from the SD scheduler of Con Kolivas: |
| 143 | */ |
Nicholas Mc Guire | 58ac93e | 2015-05-15 21:05:42 +0200 | [diff] [blame] | 144 | static unsigned int get_update_sysctl_factor(void) |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 145 | { |
Nicholas Mc Guire | 58ac93e | 2015-05-15 21:05:42 +0200 | [diff] [blame] | 146 | unsigned int cpus = min_t(unsigned int, num_online_cpus(), 8); |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 147 | unsigned int factor; |
| 148 | |
| 149 | switch (sysctl_sched_tunable_scaling) { |
| 150 | case SCHED_TUNABLESCALING_NONE: |
| 151 | factor = 1; |
| 152 | break; |
| 153 | case SCHED_TUNABLESCALING_LINEAR: |
| 154 | factor = cpus; |
| 155 | break; |
| 156 | case SCHED_TUNABLESCALING_LOG: |
| 157 | default: |
| 158 | factor = 1 + ilog2(cpus); |
| 159 | break; |
| 160 | } |
| 161 | |
| 162 | return factor; |
| 163 | } |
| 164 | |
| 165 | static void update_sysctl(void) |
| 166 | { |
| 167 | unsigned int factor = get_update_sysctl_factor(); |
| 168 | |
| 169 | #define SET_SYSCTL(name) \ |
| 170 | (sysctl_##name = (factor) * normalized_sysctl_##name) |
| 171 | SET_SYSCTL(sched_min_granularity); |
| 172 | SET_SYSCTL(sched_latency); |
| 173 | SET_SYSCTL(sched_wakeup_granularity); |
| 174 | #undef SET_SYSCTL |
| 175 | } |
| 176 | |
| 177 | void sched_init_granularity(void) |
| 178 | { |
| 179 | update_sysctl(); |
| 180 | } |
| 181 | |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 182 | #define WMULT_CONST (~0U) |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 183 | #define WMULT_SHIFT 32 |
| 184 | |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 185 | static void __update_inv_weight(struct load_weight *lw) |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 186 | { |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 187 | unsigned long w; |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 188 | |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 189 | if (likely(lw->inv_weight)) |
| 190 | return; |
| 191 | |
| 192 | w = scale_load_down(lw->weight); |
| 193 | |
| 194 | if (BITS_PER_LONG > 32 && unlikely(w >= WMULT_CONST)) |
| 195 | lw->inv_weight = 1; |
| 196 | else if (unlikely(!w)) |
| 197 | lw->inv_weight = WMULT_CONST; |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 198 | else |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 199 | lw->inv_weight = WMULT_CONST / w; |
| 200 | } |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 201 | |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 202 | /* |
| 203 | * delta_exec * weight / lw.weight |
| 204 | * OR |
| 205 | * (delta_exec * (weight * lw->inv_weight)) >> WMULT_SHIFT |
| 206 | * |
| 207 | * Either weight := NICE_0_LOAD and lw \e prio_to_wmult[], in which case |
| 208 | * we're guaranteed shift stays positive because inv_weight is guaranteed to |
| 209 | * fit 32 bits, and NICE_0_LOAD gives another 10 bits; therefore shift >= 22. |
| 210 | * |
| 211 | * Or, weight =< lw.weight (because lw.weight is the runqueue weight), thus |
| 212 | * weight/lw.weight <= 1, and therefore our shift will also be positive. |
| 213 | */ |
| 214 | static u64 __calc_delta(u64 delta_exec, unsigned long weight, struct load_weight *lw) |
| 215 | { |
| 216 | u64 fact = scale_load_down(weight); |
| 217 | int shift = WMULT_SHIFT; |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 218 | |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 219 | __update_inv_weight(lw); |
| 220 | |
| 221 | if (unlikely(fact >> 32)) { |
| 222 | while (fact >> 32) { |
| 223 | fact >>= 1; |
| 224 | shift--; |
| 225 | } |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 226 | } |
| 227 | |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 228 | /* hint to use a 32x32->64 mul */ |
| 229 | fact = (u64)(u32)fact * lw->inv_weight; |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 230 | |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 231 | while (fact >> 32) { |
| 232 | fact >>= 1; |
| 233 | shift--; |
| 234 | } |
| 235 | |
| 236 | return mul_u64_u32_shr(delta_exec, fact, shift); |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 237 | } |
| 238 | |
| 239 | |
| 240 | const struct sched_class fair_sched_class; |
Peter Zijlstra | a4c2f00 | 2008-10-17 19:27:03 +0200 | [diff] [blame] | 241 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 242 | /************************************************************** |
| 243 | * CFS operations on generic schedulable entities: |
| 244 | */ |
| 245 | |
| 246 | #ifdef CONFIG_FAIR_GROUP_SCHED |
| 247 | |
| 248 | /* cpu runqueue to which this cfs_rq is attached */ |
| 249 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
| 250 | { |
| 251 | return cfs_rq->rq; |
| 252 | } |
| 253 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 254 | /* An entity is a task if it doesn't "own" a runqueue */ |
| 255 | #define entity_is_task(se) (!se->my_q) |
| 256 | |
Peter Zijlstra | 8f48894 | 2009-07-24 12:25:30 +0200 | [diff] [blame] | 257 | static inline struct task_struct *task_of(struct sched_entity *se) |
| 258 | { |
| 259 | #ifdef CONFIG_SCHED_DEBUG |
| 260 | WARN_ON_ONCE(!entity_is_task(se)); |
| 261 | #endif |
| 262 | return container_of(se, struct task_struct, se); |
| 263 | } |
| 264 | |
Peter Zijlstra | b758149 | 2008-04-19 19:45:00 +0200 | [diff] [blame] | 265 | /* Walk up scheduling entities hierarchy */ |
| 266 | #define for_each_sched_entity(se) \ |
| 267 | for (; se; se = se->parent) |
| 268 | |
| 269 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) |
| 270 | { |
| 271 | return p->se.cfs_rq; |
| 272 | } |
| 273 | |
| 274 | /* runqueue on which this entity is (to be) queued */ |
| 275 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) |
| 276 | { |
| 277 | return se->cfs_rq; |
| 278 | } |
| 279 | |
| 280 | /* runqueue "owned" by this group */ |
| 281 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) |
| 282 | { |
| 283 | return grp->my_q; |
| 284 | } |
| 285 | |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 286 | static void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq, |
| 287 | int force_update); |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 288 | |
Peter Zijlstra | 3d4b47b | 2010-11-15 15:47:01 -0800 | [diff] [blame] | 289 | static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) |
| 290 | { |
| 291 | if (!cfs_rq->on_list) { |
Paul Turner | 67e8625 | 2010-11-15 15:47:05 -0800 | [diff] [blame] | 292 | /* |
| 293 | * Ensure we either appear before our parent (if already |
| 294 | * enqueued) or force our parent to appear after us when it is |
| 295 | * enqueued. The fact that we always enqueue bottom-up |
| 296 | * reduces this to two cases. |
| 297 | */ |
| 298 | if (cfs_rq->tg->parent && |
| 299 | cfs_rq->tg->parent->cfs_rq[cpu_of(rq_of(cfs_rq))]->on_list) { |
| 300 | list_add_rcu(&cfs_rq->leaf_cfs_rq_list, |
Peter Zijlstra | 3d4b47b | 2010-11-15 15:47:01 -0800 | [diff] [blame] | 301 | &rq_of(cfs_rq)->leaf_cfs_rq_list); |
Paul Turner | 67e8625 | 2010-11-15 15:47:05 -0800 | [diff] [blame] | 302 | } else { |
| 303 | list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list, |
| 304 | &rq_of(cfs_rq)->leaf_cfs_rq_list); |
| 305 | } |
Peter Zijlstra | 3d4b47b | 2010-11-15 15:47:01 -0800 | [diff] [blame] | 306 | |
| 307 | cfs_rq->on_list = 1; |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 308 | /* We should have no load, but we need to update last_decay. */ |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 309 | update_cfs_rq_blocked_load(cfs_rq, 0); |
Peter Zijlstra | 3d4b47b | 2010-11-15 15:47:01 -0800 | [diff] [blame] | 310 | } |
| 311 | } |
| 312 | |
| 313 | static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) |
| 314 | { |
| 315 | if (cfs_rq->on_list) { |
| 316 | list_del_rcu(&cfs_rq->leaf_cfs_rq_list); |
| 317 | cfs_rq->on_list = 0; |
| 318 | } |
| 319 | } |
| 320 | |
Peter Zijlstra | b758149 | 2008-04-19 19:45:00 +0200 | [diff] [blame] | 321 | /* Iterate thr' all leaf cfs_rq's on a runqueue */ |
| 322 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ |
| 323 | list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list) |
| 324 | |
| 325 | /* Do the two (enqueued) entities belong to the same group ? */ |
Peter Zijlstra | fed14d4 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 326 | static inline struct cfs_rq * |
Peter Zijlstra | b758149 | 2008-04-19 19:45:00 +0200 | [diff] [blame] | 327 | is_same_group(struct sched_entity *se, struct sched_entity *pse) |
| 328 | { |
| 329 | if (se->cfs_rq == pse->cfs_rq) |
Peter Zijlstra | fed14d4 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 330 | return se->cfs_rq; |
Peter Zijlstra | b758149 | 2008-04-19 19:45:00 +0200 | [diff] [blame] | 331 | |
Peter Zijlstra | fed14d4 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 332 | return NULL; |
Peter Zijlstra | b758149 | 2008-04-19 19:45:00 +0200 | [diff] [blame] | 333 | } |
| 334 | |
| 335 | static inline struct sched_entity *parent_entity(struct sched_entity *se) |
| 336 | { |
| 337 | return se->parent; |
| 338 | } |
| 339 | |
Peter Zijlstra | 464b752 | 2008-10-24 11:06:15 +0200 | [diff] [blame] | 340 | static void |
| 341 | find_matching_se(struct sched_entity **se, struct sched_entity **pse) |
| 342 | { |
| 343 | int se_depth, pse_depth; |
| 344 | |
| 345 | /* |
| 346 | * preemption test can be made between sibling entities who are in the |
| 347 | * same cfs_rq i.e who have a common parent. Walk up the hierarchy of |
| 348 | * both tasks until we find their ancestors who are siblings of common |
| 349 | * parent. |
| 350 | */ |
| 351 | |
| 352 | /* First walk up until both entities are at same depth */ |
Peter Zijlstra | fed14d4 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 353 | se_depth = (*se)->depth; |
| 354 | pse_depth = (*pse)->depth; |
Peter Zijlstra | 464b752 | 2008-10-24 11:06:15 +0200 | [diff] [blame] | 355 | |
| 356 | while (se_depth > pse_depth) { |
| 357 | se_depth--; |
| 358 | *se = parent_entity(*se); |
| 359 | } |
| 360 | |
| 361 | while (pse_depth > se_depth) { |
| 362 | pse_depth--; |
| 363 | *pse = parent_entity(*pse); |
| 364 | } |
| 365 | |
| 366 | while (!is_same_group(*se, *pse)) { |
| 367 | *se = parent_entity(*se); |
| 368 | *pse = parent_entity(*pse); |
| 369 | } |
| 370 | } |
| 371 | |
Peter Zijlstra | 8f48894 | 2009-07-24 12:25:30 +0200 | [diff] [blame] | 372 | #else /* !CONFIG_FAIR_GROUP_SCHED */ |
| 373 | |
| 374 | static inline struct task_struct *task_of(struct sched_entity *se) |
| 375 | { |
| 376 | return container_of(se, struct task_struct, se); |
| 377 | } |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 378 | |
| 379 | static inline struct rq *rq_of(struct cfs_rq *cfs_rq) |
| 380 | { |
| 381 | return container_of(cfs_rq, struct rq, cfs); |
| 382 | } |
| 383 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 384 | #define entity_is_task(se) 1 |
| 385 | |
Peter Zijlstra | b758149 | 2008-04-19 19:45:00 +0200 | [diff] [blame] | 386 | #define for_each_sched_entity(se) \ |
| 387 | for (; se; se = NULL) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 388 | |
Peter Zijlstra | b758149 | 2008-04-19 19:45:00 +0200 | [diff] [blame] | 389 | static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 390 | { |
Peter Zijlstra | b758149 | 2008-04-19 19:45:00 +0200 | [diff] [blame] | 391 | return &task_rq(p)->cfs; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 392 | } |
| 393 | |
Peter Zijlstra | b758149 | 2008-04-19 19:45:00 +0200 | [diff] [blame] | 394 | static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) |
| 395 | { |
| 396 | struct task_struct *p = task_of(se); |
| 397 | struct rq *rq = task_rq(p); |
| 398 | |
| 399 | return &rq->cfs; |
| 400 | } |
| 401 | |
| 402 | /* runqueue "owned" by this group */ |
| 403 | static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) |
| 404 | { |
| 405 | return NULL; |
| 406 | } |
| 407 | |
Peter Zijlstra | 3d4b47b | 2010-11-15 15:47:01 -0800 | [diff] [blame] | 408 | static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) |
| 409 | { |
| 410 | } |
| 411 | |
| 412 | static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) |
| 413 | { |
| 414 | } |
| 415 | |
Peter Zijlstra | b758149 | 2008-04-19 19:45:00 +0200 | [diff] [blame] | 416 | #define for_each_leaf_cfs_rq(rq, cfs_rq) \ |
| 417 | for (cfs_rq = &rq->cfs; cfs_rq; cfs_rq = NULL) |
| 418 | |
Peter Zijlstra | b758149 | 2008-04-19 19:45:00 +0200 | [diff] [blame] | 419 | static inline struct sched_entity *parent_entity(struct sched_entity *se) |
| 420 | { |
| 421 | return NULL; |
| 422 | } |
| 423 | |
Peter Zijlstra | 464b752 | 2008-10-24 11:06:15 +0200 | [diff] [blame] | 424 | static inline void |
| 425 | find_matching_se(struct sched_entity **se, struct sched_entity **pse) |
| 426 | { |
| 427 | } |
| 428 | |
Peter Zijlstra | b758149 | 2008-04-19 19:45:00 +0200 | [diff] [blame] | 429 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
| 430 | |
Peter Zijlstra | 6c16a6d | 2012-03-21 13:07:16 -0700 | [diff] [blame] | 431 | static __always_inline |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 432 | void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 433 | |
| 434 | /************************************************************** |
| 435 | * Scheduling class tree data structure manipulation methods: |
| 436 | */ |
| 437 | |
Andrei Epure | 1bf0823 | 2013-03-12 21:12:24 +0200 | [diff] [blame] | 438 | static inline u64 max_vruntime(u64 max_vruntime, u64 vruntime) |
Peter Zijlstra | 02e0431 | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 439 | { |
Andrei Epure | 1bf0823 | 2013-03-12 21:12:24 +0200 | [diff] [blame] | 440 | s64 delta = (s64)(vruntime - max_vruntime); |
Peter Zijlstra | 368059a | 2007-10-15 17:00:11 +0200 | [diff] [blame] | 441 | if (delta > 0) |
Andrei Epure | 1bf0823 | 2013-03-12 21:12:24 +0200 | [diff] [blame] | 442 | max_vruntime = vruntime; |
Peter Zijlstra | 02e0431 | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 443 | |
Andrei Epure | 1bf0823 | 2013-03-12 21:12:24 +0200 | [diff] [blame] | 444 | return max_vruntime; |
Peter Zijlstra | 02e0431 | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 445 | } |
| 446 | |
Ingo Molnar | 0702e3e | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 447 | static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime) |
Peter Zijlstra | b0ffd24 | 2007-10-15 17:00:12 +0200 | [diff] [blame] | 448 | { |
| 449 | s64 delta = (s64)(vruntime - min_vruntime); |
| 450 | if (delta < 0) |
| 451 | min_vruntime = vruntime; |
| 452 | |
| 453 | return min_vruntime; |
| 454 | } |
| 455 | |
Fabio Checconi | 54fdc58 | 2009-07-16 12:32:27 +0200 | [diff] [blame] | 456 | static inline int entity_before(struct sched_entity *a, |
| 457 | struct sched_entity *b) |
| 458 | { |
| 459 | return (s64)(a->vruntime - b->vruntime) < 0; |
| 460 | } |
| 461 | |
Peter Zijlstra | 1af5f73 | 2008-10-24 11:06:13 +0200 | [diff] [blame] | 462 | static void update_min_vruntime(struct cfs_rq *cfs_rq) |
| 463 | { |
| 464 | u64 vruntime = cfs_rq->min_vruntime; |
| 465 | |
| 466 | if (cfs_rq->curr) |
| 467 | vruntime = cfs_rq->curr->vruntime; |
| 468 | |
| 469 | if (cfs_rq->rb_leftmost) { |
| 470 | struct sched_entity *se = rb_entry(cfs_rq->rb_leftmost, |
| 471 | struct sched_entity, |
| 472 | run_node); |
| 473 | |
Peter Zijlstra | e17036d | 2009-01-15 14:53:39 +0100 | [diff] [blame] | 474 | if (!cfs_rq->curr) |
Peter Zijlstra | 1af5f73 | 2008-10-24 11:06:13 +0200 | [diff] [blame] | 475 | vruntime = se->vruntime; |
| 476 | else |
| 477 | vruntime = min_vruntime(vruntime, se->vruntime); |
| 478 | } |
| 479 | |
Andrei Epure | 1bf0823 | 2013-03-12 21:12:24 +0200 | [diff] [blame] | 480 | /* ensure we never gain time by being placed backwards. */ |
Peter Zijlstra | 1af5f73 | 2008-10-24 11:06:13 +0200 | [diff] [blame] | 481 | cfs_rq->min_vruntime = max_vruntime(cfs_rq->min_vruntime, vruntime); |
Peter Zijlstra | 3fe1698 | 2011-04-05 17:23:48 +0200 | [diff] [blame] | 482 | #ifndef CONFIG_64BIT |
| 483 | smp_wmb(); |
| 484 | cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime; |
| 485 | #endif |
Peter Zijlstra | 1af5f73 | 2008-10-24 11:06:13 +0200 | [diff] [blame] | 486 | } |
| 487 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 488 | /* |
| 489 | * Enqueue an entity into the rb-tree: |
| 490 | */ |
Ingo Molnar | 0702e3e | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 491 | static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 492 | { |
| 493 | struct rb_node **link = &cfs_rq->tasks_timeline.rb_node; |
| 494 | struct rb_node *parent = NULL; |
| 495 | struct sched_entity *entry; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 496 | int leftmost = 1; |
| 497 | |
| 498 | /* |
| 499 | * Find the right place in the rbtree: |
| 500 | */ |
| 501 | while (*link) { |
| 502 | parent = *link; |
| 503 | entry = rb_entry(parent, struct sched_entity, run_node); |
| 504 | /* |
| 505 | * We dont care about collisions. Nodes with |
| 506 | * the same key stay together. |
| 507 | */ |
Stephan Baerwolf | 2bd2d6f | 2011-07-20 14:46:59 +0200 | [diff] [blame] | 508 | if (entity_before(se, entry)) { |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 509 | link = &parent->rb_left; |
| 510 | } else { |
| 511 | link = &parent->rb_right; |
| 512 | leftmost = 0; |
| 513 | } |
| 514 | } |
| 515 | |
| 516 | /* |
| 517 | * Maintain a cache of leftmost tree entries (it is frequently |
| 518 | * used): |
| 519 | */ |
Peter Zijlstra | 1af5f73 | 2008-10-24 11:06:13 +0200 | [diff] [blame] | 520 | if (leftmost) |
Ingo Molnar | 57cb499 | 2007-10-15 17:00:11 +0200 | [diff] [blame] | 521 | cfs_rq->rb_leftmost = &se->run_node; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 522 | |
| 523 | rb_link_node(&se->run_node, parent, link); |
| 524 | rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 525 | } |
| 526 | |
Ingo Molnar | 0702e3e | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 527 | static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 528 | { |
Peter Zijlstra | 3fe6974 | 2008-03-14 20:55:51 +0100 | [diff] [blame] | 529 | if (cfs_rq->rb_leftmost == &se->run_node) { |
| 530 | struct rb_node *next_node; |
Peter Zijlstra | 3fe6974 | 2008-03-14 20:55:51 +0100 | [diff] [blame] | 531 | |
| 532 | next_node = rb_next(&se->run_node); |
| 533 | cfs_rq->rb_leftmost = next_node; |
Peter Zijlstra | 3fe6974 | 2008-03-14 20:55:51 +0100 | [diff] [blame] | 534 | } |
Ingo Molnar | e9acbff | 2007-10-15 17:00:04 +0200 | [diff] [blame] | 535 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 536 | rb_erase(&se->run_node, &cfs_rq->tasks_timeline); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 537 | } |
| 538 | |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 539 | struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 540 | { |
Peter Zijlstra | f4b6755 | 2008-11-04 21:25:07 +0100 | [diff] [blame] | 541 | struct rb_node *left = cfs_rq->rb_leftmost; |
| 542 | |
| 543 | if (!left) |
| 544 | return NULL; |
| 545 | |
| 546 | return rb_entry(left, struct sched_entity, run_node); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 547 | } |
| 548 | |
Rik van Riel | ac53db5 | 2011-02-01 09:51:03 -0500 | [diff] [blame] | 549 | static struct sched_entity *__pick_next_entity(struct sched_entity *se) |
| 550 | { |
| 551 | struct rb_node *next = rb_next(&se->run_node); |
| 552 | |
| 553 | if (!next) |
| 554 | return NULL; |
| 555 | |
| 556 | return rb_entry(next, struct sched_entity, run_node); |
| 557 | } |
| 558 | |
| 559 | #ifdef CONFIG_SCHED_DEBUG |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 560 | struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq) |
Peter Zijlstra | aeb73b0 | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 561 | { |
Ingo Molnar | 7eee3e6 | 2008-02-22 10:32:21 +0100 | [diff] [blame] | 562 | struct rb_node *last = rb_last(&cfs_rq->tasks_timeline); |
Peter Zijlstra | aeb73b0 | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 563 | |
Balbir Singh | 70eee74 | 2008-02-22 13:25:53 +0530 | [diff] [blame] | 564 | if (!last) |
| 565 | return NULL; |
Ingo Molnar | 7eee3e6 | 2008-02-22 10:32:21 +0100 | [diff] [blame] | 566 | |
| 567 | return rb_entry(last, struct sched_entity, run_node); |
Peter Zijlstra | aeb73b0 | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 568 | } |
| 569 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 570 | /************************************************************** |
| 571 | * Scheduling class statistics methods: |
| 572 | */ |
| 573 | |
Christian Ehrhardt | acb4a84 | 2009-11-30 12:16:48 +0100 | [diff] [blame] | 574 | int sched_proc_update_handler(struct ctl_table *table, int write, |
Alexey Dobriyan | 8d65af7 | 2009-09-23 15:57:19 -0700 | [diff] [blame] | 575 | void __user *buffer, size_t *lenp, |
Peter Zijlstra | b2be5e9 | 2007-11-09 22:39:37 +0100 | [diff] [blame] | 576 | loff_t *ppos) |
| 577 | { |
Alexey Dobriyan | 8d65af7 | 2009-09-23 15:57:19 -0700 | [diff] [blame] | 578 | int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
Nicholas Mc Guire | 58ac93e | 2015-05-15 21:05:42 +0200 | [diff] [blame] | 579 | unsigned int factor = get_update_sysctl_factor(); |
Peter Zijlstra | b2be5e9 | 2007-11-09 22:39:37 +0100 | [diff] [blame] | 580 | |
| 581 | if (ret || !write) |
| 582 | return ret; |
| 583 | |
| 584 | sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency, |
| 585 | sysctl_sched_min_granularity); |
| 586 | |
Christian Ehrhardt | acb4a84 | 2009-11-30 12:16:48 +0100 | [diff] [blame] | 587 | #define WRT_SYSCTL(name) \ |
| 588 | (normalized_sysctl_##name = sysctl_##name / (factor)) |
| 589 | WRT_SYSCTL(sched_min_granularity); |
| 590 | WRT_SYSCTL(sched_latency); |
| 591 | WRT_SYSCTL(sched_wakeup_granularity); |
Christian Ehrhardt | acb4a84 | 2009-11-30 12:16:48 +0100 | [diff] [blame] | 592 | #undef WRT_SYSCTL |
| 593 | |
Peter Zijlstra | b2be5e9 | 2007-11-09 22:39:37 +0100 | [diff] [blame] | 594 | return 0; |
| 595 | } |
| 596 | #endif |
Ingo Molnar | 647e7ca | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 597 | |
| 598 | /* |
Peter Zijlstra | f9c0b09 | 2008-10-17 19:27:04 +0200 | [diff] [blame] | 599 | * delta /= w |
Peter Zijlstra | a7be37a | 2008-06-27 13:41:11 +0200 | [diff] [blame] | 600 | */ |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 601 | static inline u64 calc_delta_fair(u64 delta, struct sched_entity *se) |
Peter Zijlstra | a7be37a | 2008-06-27 13:41:11 +0200 | [diff] [blame] | 602 | { |
Peter Zijlstra | f9c0b09 | 2008-10-17 19:27:04 +0200 | [diff] [blame] | 603 | if (unlikely(se->load.weight != NICE_0_LOAD)) |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 604 | delta = __calc_delta(delta, NICE_0_LOAD, &se->load); |
Peter Zijlstra | a7be37a | 2008-06-27 13:41:11 +0200 | [diff] [blame] | 605 | |
| 606 | return delta; |
| 607 | } |
| 608 | |
| 609 | /* |
Ingo Molnar | 647e7ca | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 610 | * The idea is to set a period in which each task runs once. |
| 611 | * |
Borislav Petkov | 532b185 | 2012-08-08 16:16:04 +0200 | [diff] [blame] | 612 | * When there are too many tasks (sched_nr_latency) we have to stretch |
Ingo Molnar | 647e7ca | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 613 | * this period because otherwise the slices get too small. |
| 614 | * |
| 615 | * p = (nr <= nl) ? l : l*nr/nl |
| 616 | */ |
Peter Zijlstra | 4d78e7b | 2007-10-15 17:00:04 +0200 | [diff] [blame] | 617 | static u64 __sched_period(unsigned long nr_running) |
| 618 | { |
| 619 | u64 period = sysctl_sched_latency; |
Peter Zijlstra | b2be5e9 | 2007-11-09 22:39:37 +0100 | [diff] [blame] | 620 | unsigned long nr_latency = sched_nr_latency; |
Peter Zijlstra | 4d78e7b | 2007-10-15 17:00:04 +0200 | [diff] [blame] | 621 | |
| 622 | if (unlikely(nr_running > nr_latency)) { |
Peter Zijlstra | 4bf0b77 | 2008-01-25 21:08:21 +0100 | [diff] [blame] | 623 | period = sysctl_sched_min_granularity; |
Peter Zijlstra | 4d78e7b | 2007-10-15 17:00:04 +0200 | [diff] [blame] | 624 | period *= nr_running; |
Peter Zijlstra | 4d78e7b | 2007-10-15 17:00:04 +0200 | [diff] [blame] | 625 | } |
| 626 | |
| 627 | return period; |
| 628 | } |
| 629 | |
Ingo Molnar | 647e7ca | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 630 | /* |
| 631 | * We calculate the wall-time slice from the period by taking a part |
| 632 | * proportional to the weight. |
| 633 | * |
Peter Zijlstra | f9c0b09 | 2008-10-17 19:27:04 +0200 | [diff] [blame] | 634 | * s = p*P[w/rw] |
Ingo Molnar | 647e7ca | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 635 | */ |
Peter Zijlstra | 6d0f0eb | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 636 | static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) |
Peter Zijlstra | 2180508 | 2007-08-25 18:41:53 +0200 | [diff] [blame] | 637 | { |
Mike Galbraith | 0a58244 | 2009-01-02 12:16:42 +0100 | [diff] [blame] | 638 | u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq); |
Peter Zijlstra | f9c0b09 | 2008-10-17 19:27:04 +0200 | [diff] [blame] | 639 | |
Mike Galbraith | 0a58244 | 2009-01-02 12:16:42 +0100 | [diff] [blame] | 640 | for_each_sched_entity(se) { |
Lin Ming | 6272d68 | 2009-01-15 17:17:15 +0100 | [diff] [blame] | 641 | struct load_weight *load; |
Christian Engelmayer | 3104bf0 | 2009-06-16 10:35:12 +0200 | [diff] [blame] | 642 | struct load_weight lw; |
Lin Ming | 6272d68 | 2009-01-15 17:17:15 +0100 | [diff] [blame] | 643 | |
| 644 | cfs_rq = cfs_rq_of(se); |
| 645 | load = &cfs_rq->load; |
Peter Zijlstra | f9c0b09 | 2008-10-17 19:27:04 +0200 | [diff] [blame] | 646 | |
Mike Galbraith | 0a58244 | 2009-01-02 12:16:42 +0100 | [diff] [blame] | 647 | if (unlikely(!se->on_rq)) { |
Christian Engelmayer | 3104bf0 | 2009-06-16 10:35:12 +0200 | [diff] [blame] | 648 | lw = cfs_rq->load; |
Mike Galbraith | 0a58244 | 2009-01-02 12:16:42 +0100 | [diff] [blame] | 649 | |
| 650 | update_load_add(&lw, se->load.weight); |
| 651 | load = &lw; |
| 652 | } |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 653 | slice = __calc_delta(slice, se->load.weight, load); |
Mike Galbraith | 0a58244 | 2009-01-02 12:16:42 +0100 | [diff] [blame] | 654 | } |
| 655 | return slice; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 656 | } |
| 657 | |
Ingo Molnar | 647e7ca | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 658 | /* |
Andrei Epure | 660cc00 | 2013-03-11 12:03:20 +0200 | [diff] [blame] | 659 | * We calculate the vruntime slice of a to-be-inserted task. |
Ingo Molnar | 647e7ca | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 660 | * |
Peter Zijlstra | f9c0b09 | 2008-10-17 19:27:04 +0200 | [diff] [blame] | 661 | * vs = s/w |
Ingo Molnar | 647e7ca | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 662 | */ |
Peter Zijlstra | f9c0b09 | 2008-10-17 19:27:04 +0200 | [diff] [blame] | 663 | static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se) |
Ingo Molnar | 647e7ca | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 664 | { |
Peter Zijlstra | f9c0b09 | 2008-10-17 19:27:04 +0200 | [diff] [blame] | 665 | return calc_delta_fair(sched_slice(cfs_rq, se), se); |
Peter Zijlstra | a7be37a | 2008-06-27 13:41:11 +0200 | [diff] [blame] | 666 | } |
| 667 | |
Alex Shi | a75cdaa | 2013-06-20 10:18:47 +0800 | [diff] [blame] | 668 | #ifdef CONFIG_SMP |
Rik van Riel | ba7e5a2 | 2014-09-04 16:35:30 -0400 | [diff] [blame] | 669 | static int select_idle_sibling(struct task_struct *p, int cpu); |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 670 | static unsigned long task_h_load(struct task_struct *p); |
| 671 | |
Alex Shi | a75cdaa | 2013-06-20 10:18:47 +0800 | [diff] [blame] | 672 | static inline void __update_task_entity_contrib(struct sched_entity *se); |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 673 | static inline void __update_task_entity_utilization(struct sched_entity *se); |
Alex Shi | a75cdaa | 2013-06-20 10:18:47 +0800 | [diff] [blame] | 674 | |
| 675 | /* Give new task start runnable values to heavy its load in infant time */ |
| 676 | void init_task_runnable_average(struct task_struct *p) |
| 677 | { |
| 678 | u32 slice; |
| 679 | |
Alex Shi | a75cdaa | 2013-06-20 10:18:47 +0800 | [diff] [blame] | 680 | slice = sched_slice(task_cfs_rq(p), &p->se) >> 10; |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 681 | p->se.avg.runnable_avg_sum = p->se.avg.running_avg_sum = slice; |
| 682 | p->se.avg.avg_period = slice; |
Alex Shi | a75cdaa | 2013-06-20 10:18:47 +0800 | [diff] [blame] | 683 | __update_task_entity_contrib(&p->se); |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 684 | __update_task_entity_utilization(&p->se); |
Alex Shi | a75cdaa | 2013-06-20 10:18:47 +0800 | [diff] [blame] | 685 | } |
| 686 | #else |
| 687 | void init_task_runnable_average(struct task_struct *p) |
| 688 | { |
| 689 | } |
| 690 | #endif |
| 691 | |
Peter Zijlstra | a7be37a | 2008-06-27 13:41:11 +0200 | [diff] [blame] | 692 | /* |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 693 | * Update the current task's runtime statistics. |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 694 | */ |
Ingo Molnar | b7cc089 | 2007-08-09 11:16:47 +0200 | [diff] [blame] | 695 | static void update_curr(struct cfs_rq *cfs_rq) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 696 | { |
Ingo Molnar | 429d43b | 2007-10-15 17:00:03 +0200 | [diff] [blame] | 697 | struct sched_entity *curr = cfs_rq->curr; |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 698 | u64 now = rq_clock_task(rq_of(cfs_rq)); |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 699 | u64 delta_exec; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 700 | |
| 701 | if (unlikely(!curr)) |
| 702 | return; |
| 703 | |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 704 | delta_exec = now - curr->exec_start; |
| 705 | if (unlikely((s64)delta_exec <= 0)) |
Peter Zijlstra | 34f28ec | 2008-12-16 08:45:31 +0100 | [diff] [blame] | 706 | return; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 707 | |
Ingo Molnar | 8ebc91d | 2007-10-15 17:00:03 +0200 | [diff] [blame] | 708 | curr->exec_start = now; |
Srivatsa Vaddagiri | d842de8 | 2007-12-02 20:04:49 +0100 | [diff] [blame] | 709 | |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 710 | schedstat_set(curr->statistics.exec_max, |
| 711 | max(delta_exec, curr->statistics.exec_max)); |
| 712 | |
| 713 | curr->sum_exec_runtime += delta_exec; |
| 714 | schedstat_add(cfs_rq, exec_clock, delta_exec); |
| 715 | |
| 716 | curr->vruntime += calc_delta_fair(delta_exec, curr); |
| 717 | update_min_vruntime(cfs_rq); |
| 718 | |
Srivatsa Vaddagiri | d842de8 | 2007-12-02 20:04:49 +0100 | [diff] [blame] | 719 | if (entity_is_task(curr)) { |
| 720 | struct task_struct *curtask = task_of(curr); |
| 721 | |
Ingo Molnar | f977bb4 | 2009-09-13 18:15:54 +0200 | [diff] [blame] | 722 | trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime); |
Srivatsa Vaddagiri | d842de8 | 2007-12-02 20:04:49 +0100 | [diff] [blame] | 723 | cpuacct_charge(curtask, delta_exec); |
Frank Mayhar | f06febc | 2008-09-12 09:54:39 -0700 | [diff] [blame] | 724 | account_group_exec_runtime(curtask, delta_exec); |
Srivatsa Vaddagiri | d842de8 | 2007-12-02 20:04:49 +0100 | [diff] [blame] | 725 | } |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 726 | |
| 727 | account_cfs_rq_runtime(cfs_rq, delta_exec); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 728 | } |
| 729 | |
Stanislaw Gruszka | 6e99891 | 2014-11-12 16:58:44 +0100 | [diff] [blame] | 730 | static void update_curr_fair(struct rq *rq) |
| 731 | { |
| 732 | update_curr(cfs_rq_of(&rq->curr->se)); |
| 733 | } |
| 734 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 735 | static inline void |
Ingo Molnar | 5870db5 | 2007-08-09 11:16:47 +0200 | [diff] [blame] | 736 | update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 737 | { |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 738 | schedstat_set(se->statistics.wait_start, rq_clock(rq_of(cfs_rq))); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 739 | } |
| 740 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 741 | /* |
| 742 | * Task is being enqueued - update stats: |
| 743 | */ |
Ingo Molnar | d2417e5 | 2007-08-09 11:16:47 +0200 | [diff] [blame] | 744 | static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 745 | { |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 746 | /* |
| 747 | * Are we enqueueing a waiting task? (for current tasks |
| 748 | * a dequeue/enqueue event is a NOP) |
| 749 | */ |
Ingo Molnar | 429d43b | 2007-10-15 17:00:03 +0200 | [diff] [blame] | 750 | if (se != cfs_rq->curr) |
Ingo Molnar | 5870db5 | 2007-08-09 11:16:47 +0200 | [diff] [blame] | 751 | update_stats_wait_start(cfs_rq, se); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 752 | } |
| 753 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 754 | static void |
Ingo Molnar | 9ef0a96 | 2007-08-09 11:16:47 +0200 | [diff] [blame] | 755 | update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 756 | { |
Lucas De Marchi | 41acab8 | 2010-03-10 23:37:45 -0300 | [diff] [blame] | 757 | schedstat_set(se->statistics.wait_max, max(se->statistics.wait_max, |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 758 | rq_clock(rq_of(cfs_rq)) - se->statistics.wait_start)); |
Lucas De Marchi | 41acab8 | 2010-03-10 23:37:45 -0300 | [diff] [blame] | 759 | schedstat_set(se->statistics.wait_count, se->statistics.wait_count + 1); |
| 760 | schedstat_set(se->statistics.wait_sum, se->statistics.wait_sum + |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 761 | rq_clock(rq_of(cfs_rq)) - se->statistics.wait_start); |
Peter Zijlstra | 768d0c2 | 2009-07-23 20:13:26 +0200 | [diff] [blame] | 762 | #ifdef CONFIG_SCHEDSTATS |
| 763 | if (entity_is_task(se)) { |
| 764 | trace_sched_stat_wait(task_of(se), |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 765 | rq_clock(rq_of(cfs_rq)) - se->statistics.wait_start); |
Peter Zijlstra | 768d0c2 | 2009-07-23 20:13:26 +0200 | [diff] [blame] | 766 | } |
| 767 | #endif |
Lucas De Marchi | 41acab8 | 2010-03-10 23:37:45 -0300 | [diff] [blame] | 768 | schedstat_set(se->statistics.wait_start, 0); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 769 | } |
| 770 | |
| 771 | static inline void |
Ingo Molnar | 19b6a2e | 2007-08-09 11:16:48 +0200 | [diff] [blame] | 772 | update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 773 | { |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 774 | /* |
| 775 | * Mark the end of the wait period if dequeueing a |
| 776 | * waiting task: |
| 777 | */ |
Ingo Molnar | 429d43b | 2007-10-15 17:00:03 +0200 | [diff] [blame] | 778 | if (se != cfs_rq->curr) |
Ingo Molnar | 9ef0a96 | 2007-08-09 11:16:47 +0200 | [diff] [blame] | 779 | update_stats_wait_end(cfs_rq, se); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 780 | } |
| 781 | |
| 782 | /* |
| 783 | * We are picking a new current task - update its stats: |
| 784 | */ |
| 785 | static inline void |
Ingo Molnar | 79303e9 | 2007-08-09 11:16:47 +0200 | [diff] [blame] | 786 | update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 787 | { |
| 788 | /* |
| 789 | * We are starting a new run period: |
| 790 | */ |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 791 | se->exec_start = rq_clock_task(rq_of(cfs_rq)); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 792 | } |
| 793 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 794 | /************************************************** |
| 795 | * Scheduling class queueing methods: |
| 796 | */ |
| 797 | |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 798 | #ifdef CONFIG_NUMA_BALANCING |
| 799 | /* |
Mel Gorman | 598f0ec | 2013-10-07 11:28:55 +0100 | [diff] [blame] | 800 | * Approximate time to scan a full NUMA task in ms. The task scan period is |
| 801 | * calculated based on the tasks virtual memory size and |
| 802 | * numa_balancing_scan_size. |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 803 | */ |
Mel Gorman | 598f0ec | 2013-10-07 11:28:55 +0100 | [diff] [blame] | 804 | unsigned int sysctl_numa_balancing_scan_period_min = 1000; |
| 805 | unsigned int sysctl_numa_balancing_scan_period_max = 60000; |
Peter Zijlstra | 6e5fb22 | 2012-10-25 14:16:45 +0200 | [diff] [blame] | 806 | |
| 807 | /* Portion of address space to scan in MB */ |
| 808 | unsigned int sysctl_numa_balancing_scan_size = 256; |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 809 | |
Peter Zijlstra | 4b96a29 | 2012-10-25 14:16:47 +0200 | [diff] [blame] | 810 | /* Scan @scan_size MB every @scan_period after an initial @scan_delay in ms */ |
| 811 | unsigned int sysctl_numa_balancing_scan_delay = 1000; |
| 812 | |
Mel Gorman | 598f0ec | 2013-10-07 11:28:55 +0100 | [diff] [blame] | 813 | static unsigned int task_nr_scan_windows(struct task_struct *p) |
| 814 | { |
| 815 | unsigned long rss = 0; |
| 816 | unsigned long nr_scan_pages; |
| 817 | |
| 818 | /* |
| 819 | * Calculations based on RSS as non-present and empty pages are skipped |
| 820 | * by the PTE scanner and NUMA hinting faults should be trapped based |
| 821 | * on resident pages |
| 822 | */ |
| 823 | nr_scan_pages = sysctl_numa_balancing_scan_size << (20 - PAGE_SHIFT); |
| 824 | rss = get_mm_rss(p->mm); |
| 825 | if (!rss) |
| 826 | rss = nr_scan_pages; |
| 827 | |
| 828 | rss = round_up(rss, nr_scan_pages); |
| 829 | return rss / nr_scan_pages; |
| 830 | } |
| 831 | |
| 832 | /* For sanitys sake, never scan more PTEs than MAX_SCAN_WINDOW MB/sec. */ |
| 833 | #define MAX_SCAN_WINDOW 2560 |
| 834 | |
| 835 | static unsigned int task_scan_min(struct task_struct *p) |
| 836 | { |
Jason Low | 316c1608d | 2015-04-28 13:00:20 -0700 | [diff] [blame] | 837 | unsigned int scan_size = READ_ONCE(sysctl_numa_balancing_scan_size); |
Mel Gorman | 598f0ec | 2013-10-07 11:28:55 +0100 | [diff] [blame] | 838 | unsigned int scan, floor; |
| 839 | unsigned int windows = 1; |
| 840 | |
Kirill Tkhai | 6419265 | 2014-10-16 14:39:37 +0400 | [diff] [blame] | 841 | if (scan_size < MAX_SCAN_WINDOW) |
| 842 | windows = MAX_SCAN_WINDOW / scan_size; |
Mel Gorman | 598f0ec | 2013-10-07 11:28:55 +0100 | [diff] [blame] | 843 | floor = 1000 / windows; |
| 844 | |
| 845 | scan = sysctl_numa_balancing_scan_period_min / task_nr_scan_windows(p); |
| 846 | return max_t(unsigned int, floor, scan); |
| 847 | } |
| 848 | |
| 849 | static unsigned int task_scan_max(struct task_struct *p) |
| 850 | { |
| 851 | unsigned int smin = task_scan_min(p); |
| 852 | unsigned int smax; |
| 853 | |
| 854 | /* Watch for min being lower than max due to floor calculations */ |
| 855 | smax = sysctl_numa_balancing_scan_period_max / task_nr_scan_windows(p); |
| 856 | return max(smin, smax); |
| 857 | } |
| 858 | |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 859 | static void account_numa_enqueue(struct rq *rq, struct task_struct *p) |
| 860 | { |
| 861 | rq->nr_numa_running += (p->numa_preferred_nid != -1); |
| 862 | rq->nr_preferred_running += (p->numa_preferred_nid == task_node(p)); |
| 863 | } |
| 864 | |
| 865 | static void account_numa_dequeue(struct rq *rq, struct task_struct *p) |
| 866 | { |
| 867 | rq->nr_numa_running -= (p->numa_preferred_nid != -1); |
| 868 | rq->nr_preferred_running -= (p->numa_preferred_nid == task_node(p)); |
| 869 | } |
| 870 | |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 871 | struct numa_group { |
| 872 | atomic_t refcount; |
| 873 | |
| 874 | spinlock_t lock; /* nr_tasks, tasks */ |
| 875 | int nr_tasks; |
Mel Gorman | e29cf08 | 2013-10-07 11:29:22 +0100 | [diff] [blame] | 876 | pid_t gid; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 877 | |
| 878 | struct rcu_head rcu; |
Rik van Riel | 20e07de | 2014-01-27 17:03:43 -0500 | [diff] [blame] | 879 | nodemask_t active_nodes; |
Mel Gorman | 989348b | 2013-10-07 11:29:40 +0100 | [diff] [blame] | 880 | unsigned long total_faults; |
Rik van Riel | 7e2703e | 2014-01-27 17:03:45 -0500 | [diff] [blame] | 881 | /* |
| 882 | * Faults_cpu is used to decide whether memory should move |
| 883 | * towards the CPU. As a consequence, these stats are weighted |
| 884 | * more by CPU use than by memory faults. |
| 885 | */ |
Rik van Riel | 50ec8a4 | 2014-01-27 17:03:42 -0500 | [diff] [blame] | 886 | unsigned long *faults_cpu; |
Mel Gorman | 989348b | 2013-10-07 11:29:40 +0100 | [diff] [blame] | 887 | unsigned long faults[0]; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 888 | }; |
| 889 | |
Rik van Riel | be1e4e7 | 2014-01-27 17:03:48 -0500 | [diff] [blame] | 890 | /* Shared or private faults. */ |
| 891 | #define NR_NUMA_HINT_FAULT_TYPES 2 |
| 892 | |
| 893 | /* Memory and CPU locality */ |
| 894 | #define NR_NUMA_HINT_FAULT_STATS (NR_NUMA_HINT_FAULT_TYPES * 2) |
| 895 | |
| 896 | /* Averaged statistics, and temporary buffers. */ |
| 897 | #define NR_NUMA_HINT_FAULT_BUCKETS (NR_NUMA_HINT_FAULT_STATS * 2) |
| 898 | |
Mel Gorman | e29cf08 | 2013-10-07 11:29:22 +0100 | [diff] [blame] | 899 | pid_t task_numa_group_id(struct task_struct *p) |
| 900 | { |
| 901 | return p->numa_group ? p->numa_group->gid : 0; |
| 902 | } |
| 903 | |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 904 | /* |
| 905 | * The averaged statistics, shared & private, memory & cpu, |
| 906 | * occupy the first half of the array. The second half of the |
| 907 | * array is for current counters, which are averaged into the |
| 908 | * first set by task_numa_placement. |
| 909 | */ |
| 910 | static inline int task_faults_idx(enum numa_faults_stats s, int nid, int priv) |
Mel Gorman | ac8e895 | 2013-10-07 11:29:03 +0100 | [diff] [blame] | 911 | { |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 912 | return NR_NUMA_HINT_FAULT_TYPES * (s * nr_node_ids + nid) + priv; |
Mel Gorman | ac8e895 | 2013-10-07 11:29:03 +0100 | [diff] [blame] | 913 | } |
| 914 | |
| 915 | static inline unsigned long task_faults(struct task_struct *p, int nid) |
| 916 | { |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 917 | if (!p->numa_faults) |
Mel Gorman | ac8e895 | 2013-10-07 11:29:03 +0100 | [diff] [blame] | 918 | return 0; |
| 919 | |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 920 | return p->numa_faults[task_faults_idx(NUMA_MEM, nid, 0)] + |
| 921 | p->numa_faults[task_faults_idx(NUMA_MEM, nid, 1)]; |
Mel Gorman | ac8e895 | 2013-10-07 11:29:03 +0100 | [diff] [blame] | 922 | } |
| 923 | |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 924 | static inline unsigned long group_faults(struct task_struct *p, int nid) |
| 925 | { |
| 926 | if (!p->numa_group) |
| 927 | return 0; |
| 928 | |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 929 | return p->numa_group->faults[task_faults_idx(NUMA_MEM, nid, 0)] + |
| 930 | p->numa_group->faults[task_faults_idx(NUMA_MEM, nid, 1)]; |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 931 | } |
| 932 | |
Rik van Riel | 20e07de | 2014-01-27 17:03:43 -0500 | [diff] [blame] | 933 | static inline unsigned long group_faults_cpu(struct numa_group *group, int nid) |
| 934 | { |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 935 | return group->faults_cpu[task_faults_idx(NUMA_MEM, nid, 0)] + |
| 936 | group->faults_cpu[task_faults_idx(NUMA_MEM, nid, 1)]; |
Rik van Riel | 20e07de | 2014-01-27 17:03:43 -0500 | [diff] [blame] | 937 | } |
| 938 | |
Rik van Riel | 6c6b119 | 2014-10-17 03:29:52 -0400 | [diff] [blame] | 939 | /* Handle placement on systems where not all nodes are directly connected. */ |
| 940 | static unsigned long score_nearby_nodes(struct task_struct *p, int nid, |
| 941 | int maxdist, bool task) |
| 942 | { |
| 943 | unsigned long score = 0; |
| 944 | int node; |
| 945 | |
| 946 | /* |
| 947 | * All nodes are directly connected, and the same distance |
| 948 | * from each other. No need for fancy placement algorithms. |
| 949 | */ |
| 950 | if (sched_numa_topology_type == NUMA_DIRECT) |
| 951 | return 0; |
| 952 | |
| 953 | /* |
| 954 | * This code is called for each node, introducing N^2 complexity, |
| 955 | * which should be ok given the number of nodes rarely exceeds 8. |
| 956 | */ |
| 957 | for_each_online_node(node) { |
| 958 | unsigned long faults; |
| 959 | int dist = node_distance(nid, node); |
| 960 | |
| 961 | /* |
| 962 | * The furthest away nodes in the system are not interesting |
| 963 | * for placement; nid was already counted. |
| 964 | */ |
| 965 | if (dist == sched_max_numa_distance || node == nid) |
| 966 | continue; |
| 967 | |
| 968 | /* |
| 969 | * On systems with a backplane NUMA topology, compare groups |
| 970 | * of nodes, and move tasks towards the group with the most |
| 971 | * memory accesses. When comparing two nodes at distance |
| 972 | * "hoplimit", only nodes closer by than "hoplimit" are part |
| 973 | * of each group. Skip other nodes. |
| 974 | */ |
| 975 | if (sched_numa_topology_type == NUMA_BACKPLANE && |
| 976 | dist > maxdist) |
| 977 | continue; |
| 978 | |
| 979 | /* Add up the faults from nearby nodes. */ |
| 980 | if (task) |
| 981 | faults = task_faults(p, node); |
| 982 | else |
| 983 | faults = group_faults(p, node); |
| 984 | |
| 985 | /* |
| 986 | * On systems with a glueless mesh NUMA topology, there are |
| 987 | * no fixed "groups of nodes". Instead, nodes that are not |
| 988 | * directly connected bounce traffic through intermediate |
| 989 | * nodes; a numa_group can occupy any set of nodes. |
| 990 | * The further away a node is, the less the faults count. |
| 991 | * This seems to result in good task placement. |
| 992 | */ |
| 993 | if (sched_numa_topology_type == NUMA_GLUELESS_MESH) { |
| 994 | faults *= (sched_max_numa_distance - dist); |
| 995 | faults /= (sched_max_numa_distance - LOCAL_DISTANCE); |
| 996 | } |
| 997 | |
| 998 | score += faults; |
| 999 | } |
| 1000 | |
| 1001 | return score; |
| 1002 | } |
| 1003 | |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 1004 | /* |
| 1005 | * These return the fraction of accesses done by a particular task, or |
| 1006 | * task group, on a particular numa node. The group weight is given a |
| 1007 | * larger multiplier, in order to group tasks together that are almost |
| 1008 | * evenly spread out between numa nodes. |
| 1009 | */ |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1010 | static inline unsigned long task_weight(struct task_struct *p, int nid, |
| 1011 | int dist) |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 1012 | { |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1013 | unsigned long faults, total_faults; |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 1014 | |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 1015 | if (!p->numa_faults) |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 1016 | return 0; |
| 1017 | |
| 1018 | total_faults = p->total_numa_faults; |
| 1019 | |
| 1020 | if (!total_faults) |
| 1021 | return 0; |
| 1022 | |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1023 | faults = task_faults(p, nid); |
Rik van Riel | 6c6b119 | 2014-10-17 03:29:52 -0400 | [diff] [blame] | 1024 | faults += score_nearby_nodes(p, nid, dist, true); |
| 1025 | |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1026 | return 1000 * faults / total_faults; |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 1027 | } |
| 1028 | |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1029 | static inline unsigned long group_weight(struct task_struct *p, int nid, |
| 1030 | int dist) |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 1031 | { |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1032 | unsigned long faults, total_faults; |
| 1033 | |
| 1034 | if (!p->numa_group) |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 1035 | return 0; |
| 1036 | |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1037 | total_faults = p->numa_group->total_faults; |
| 1038 | |
| 1039 | if (!total_faults) |
| 1040 | return 0; |
| 1041 | |
| 1042 | faults = group_faults(p, nid); |
Rik van Riel | 6c6b119 | 2014-10-17 03:29:52 -0400 | [diff] [blame] | 1043 | faults += score_nearby_nodes(p, nid, dist, false); |
| 1044 | |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1045 | return 1000 * faults / total_faults; |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 1046 | } |
| 1047 | |
Rik van Riel | 10f3904 | 2014-01-27 17:03:44 -0500 | [diff] [blame] | 1048 | bool should_numa_migrate_memory(struct task_struct *p, struct page * page, |
| 1049 | int src_nid, int dst_cpu) |
| 1050 | { |
| 1051 | struct numa_group *ng = p->numa_group; |
| 1052 | int dst_nid = cpu_to_node(dst_cpu); |
| 1053 | int last_cpupid, this_cpupid; |
| 1054 | |
| 1055 | this_cpupid = cpu_pid_to_cpupid(dst_cpu, current->pid); |
| 1056 | |
| 1057 | /* |
| 1058 | * Multi-stage node selection is used in conjunction with a periodic |
| 1059 | * migration fault to build a temporal task<->page relation. By using |
| 1060 | * a two-stage filter we remove short/unlikely relations. |
| 1061 | * |
| 1062 | * Using P(p) ~ n_p / n_t as per frequentist probability, we can equate |
| 1063 | * a task's usage of a particular page (n_p) per total usage of this |
| 1064 | * page (n_t) (in a given time-span) to a probability. |
| 1065 | * |
| 1066 | * Our periodic faults will sample this probability and getting the |
| 1067 | * same result twice in a row, given these samples are fully |
| 1068 | * independent, is then given by P(n)^2, provided our sample period |
| 1069 | * is sufficiently short compared to the usage pattern. |
| 1070 | * |
| 1071 | * This quadric squishes small probabilities, making it less likely we |
| 1072 | * act on an unlikely task<->page relation. |
| 1073 | */ |
| 1074 | last_cpupid = page_cpupid_xchg_last(page, this_cpupid); |
| 1075 | if (!cpupid_pid_unset(last_cpupid) && |
| 1076 | cpupid_to_nid(last_cpupid) != dst_nid) |
| 1077 | return false; |
| 1078 | |
| 1079 | /* Always allow migrate on private faults */ |
| 1080 | if (cpupid_match_pid(p, last_cpupid)) |
| 1081 | return true; |
| 1082 | |
| 1083 | /* A shared fault, but p->numa_group has not been set up yet. */ |
| 1084 | if (!ng) |
| 1085 | return true; |
| 1086 | |
| 1087 | /* |
| 1088 | * Do not migrate if the destination is not a node that |
| 1089 | * is actively used by this numa group. |
| 1090 | */ |
| 1091 | if (!node_isset(dst_nid, ng->active_nodes)) |
| 1092 | return false; |
| 1093 | |
| 1094 | /* |
| 1095 | * Source is a node that is not actively used by this |
| 1096 | * numa group, while the destination is. Migrate. |
| 1097 | */ |
| 1098 | if (!node_isset(src_nid, ng->active_nodes)) |
| 1099 | return true; |
| 1100 | |
| 1101 | /* |
| 1102 | * Both source and destination are nodes in active |
| 1103 | * use by this numa group. Maximize memory bandwidth |
| 1104 | * by migrating from more heavily used groups, to less |
| 1105 | * heavily used ones, spreading the load around. |
| 1106 | * Use a 1/4 hysteresis to avoid spurious page movement. |
| 1107 | */ |
| 1108 | return group_faults(p, dst_nid) < (group_faults(p, src_nid) * 3 / 4); |
| 1109 | } |
| 1110 | |
Mel Gorman | e6628d5 | 2013-10-07 11:29:02 +0100 | [diff] [blame] | 1111 | static unsigned long weighted_cpuload(const int cpu); |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1112 | static unsigned long source_load(int cpu, int type); |
| 1113 | static unsigned long target_load(int cpu, int type); |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 1114 | static unsigned long capacity_of(int cpu); |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1115 | static long effective_load(struct task_group *tg, int cpu, long wl, long wg); |
Mel Gorman | e6628d5 | 2013-10-07 11:29:02 +0100 | [diff] [blame] | 1116 | |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1117 | /* Cached statistics for all CPUs within a node */ |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1118 | struct numa_stats { |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1119 | unsigned long nr_running; |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1120 | unsigned long load; |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1121 | |
| 1122 | /* Total compute capacity of CPUs on a node */ |
Nicolas Pitre | 5ef20ca | 2014-05-26 18:19:34 -0400 | [diff] [blame] | 1123 | unsigned long compute_capacity; |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1124 | |
| 1125 | /* Approximate capacity in terms of runnable tasks on a node */ |
Nicolas Pitre | 5ef20ca | 2014-05-26 18:19:34 -0400 | [diff] [blame] | 1126 | unsigned long task_capacity; |
Nicolas Pitre | 1b6a749 | 2014-05-26 18:19:35 -0400 | [diff] [blame] | 1127 | int has_free_capacity; |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1128 | }; |
Mel Gorman | e6628d5 | 2013-10-07 11:29:02 +0100 | [diff] [blame] | 1129 | |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1130 | /* |
| 1131 | * XXX borrowed from update_sg_lb_stats |
| 1132 | */ |
| 1133 | static void update_numa_stats(struct numa_stats *ns, int nid) |
| 1134 | { |
Rik van Riel | 83d7f24 | 2014-08-04 13:23:28 -0400 | [diff] [blame] | 1135 | int smt, cpu, cpus = 0; |
| 1136 | unsigned long capacity; |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1137 | |
| 1138 | memset(ns, 0, sizeof(*ns)); |
| 1139 | for_each_cpu(cpu, cpumask_of_node(nid)) { |
| 1140 | struct rq *rq = cpu_rq(cpu); |
| 1141 | |
| 1142 | ns->nr_running += rq->nr_running; |
| 1143 | ns->load += weighted_cpuload(cpu); |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 1144 | ns->compute_capacity += capacity_of(cpu); |
Peter Zijlstra | 5eca82a | 2013-11-06 18:47:57 +0100 | [diff] [blame] | 1145 | |
| 1146 | cpus++; |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1147 | } |
| 1148 | |
Peter Zijlstra | 5eca82a | 2013-11-06 18:47:57 +0100 | [diff] [blame] | 1149 | /* |
| 1150 | * If we raced with hotplug and there are no CPUs left in our mask |
| 1151 | * the @ns structure is NULL'ed and task_numa_compare() will |
| 1152 | * not find this node attractive. |
| 1153 | * |
Nicolas Pitre | 1b6a749 | 2014-05-26 18:19:35 -0400 | [diff] [blame] | 1154 | * We'll either bail at !has_free_capacity, or we'll detect a huge |
| 1155 | * imbalance and bail there. |
Peter Zijlstra | 5eca82a | 2013-11-06 18:47:57 +0100 | [diff] [blame] | 1156 | */ |
| 1157 | if (!cpus) |
| 1158 | return; |
| 1159 | |
Rik van Riel | 83d7f24 | 2014-08-04 13:23:28 -0400 | [diff] [blame] | 1160 | /* smt := ceil(cpus / capacity), assumes: 1 < smt_power < 2 */ |
| 1161 | smt = DIV_ROUND_UP(SCHED_CAPACITY_SCALE * cpus, ns->compute_capacity); |
| 1162 | capacity = cpus / smt; /* cores */ |
| 1163 | |
| 1164 | ns->task_capacity = min_t(unsigned, capacity, |
| 1165 | DIV_ROUND_CLOSEST(ns->compute_capacity, SCHED_CAPACITY_SCALE)); |
Nicolas Pitre | 1b6a749 | 2014-05-26 18:19:35 -0400 | [diff] [blame] | 1166 | ns->has_free_capacity = (ns->nr_running < ns->task_capacity); |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1167 | } |
| 1168 | |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1169 | struct task_numa_env { |
| 1170 | struct task_struct *p; |
| 1171 | |
| 1172 | int src_cpu, src_nid; |
| 1173 | int dst_cpu, dst_nid; |
| 1174 | |
| 1175 | struct numa_stats src_stats, dst_stats; |
| 1176 | |
Wanpeng Li | 40ea2b4 | 2013-12-05 19:10:17 +0800 | [diff] [blame] | 1177 | int imbalance_pct; |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1178 | int dist; |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1179 | |
| 1180 | struct task_struct *best_task; |
| 1181 | long best_imp; |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1182 | int best_cpu; |
| 1183 | }; |
| 1184 | |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1185 | static void task_numa_assign(struct task_numa_env *env, |
| 1186 | struct task_struct *p, long imp) |
| 1187 | { |
| 1188 | if (env->best_task) |
| 1189 | put_task_struct(env->best_task); |
| 1190 | if (p) |
| 1191 | get_task_struct(p); |
| 1192 | |
| 1193 | env->best_task = p; |
| 1194 | env->best_imp = imp; |
| 1195 | env->best_cpu = env->dst_cpu; |
| 1196 | } |
| 1197 | |
Rik van Riel | 28a21745 | 2014-06-23 11:46:13 -0400 | [diff] [blame] | 1198 | static bool load_too_imbalanced(long src_load, long dst_load, |
Rik van Riel | e63da03 | 2014-05-14 13:22:21 -0400 | [diff] [blame] | 1199 | struct task_numa_env *env) |
| 1200 | { |
Rik van Riel | e4991b2 | 2015-05-27 15:04:27 -0400 | [diff] [blame] | 1201 | long imb, old_imb; |
| 1202 | long orig_src_load, orig_dst_load; |
Rik van Riel | 28a21745 | 2014-06-23 11:46:13 -0400 | [diff] [blame] | 1203 | long src_capacity, dst_capacity; |
| 1204 | |
| 1205 | /* |
| 1206 | * The load is corrected for the CPU capacity available on each node. |
| 1207 | * |
| 1208 | * src_load dst_load |
| 1209 | * ------------ vs --------- |
| 1210 | * src_capacity dst_capacity |
| 1211 | */ |
| 1212 | src_capacity = env->src_stats.compute_capacity; |
| 1213 | dst_capacity = env->dst_stats.compute_capacity; |
Rik van Riel | e63da03 | 2014-05-14 13:22:21 -0400 | [diff] [blame] | 1214 | |
| 1215 | /* We care about the slope of the imbalance, not the direction. */ |
Rik van Riel | e4991b2 | 2015-05-27 15:04:27 -0400 | [diff] [blame] | 1216 | if (dst_load < src_load) |
| 1217 | swap(dst_load, src_load); |
Rik van Riel | e63da03 | 2014-05-14 13:22:21 -0400 | [diff] [blame] | 1218 | |
| 1219 | /* Is the difference below the threshold? */ |
Rik van Riel | e4991b2 | 2015-05-27 15:04:27 -0400 | [diff] [blame] | 1220 | imb = dst_load * src_capacity * 100 - |
| 1221 | src_load * dst_capacity * env->imbalance_pct; |
Rik van Riel | e63da03 | 2014-05-14 13:22:21 -0400 | [diff] [blame] | 1222 | if (imb <= 0) |
| 1223 | return false; |
| 1224 | |
| 1225 | /* |
| 1226 | * The imbalance is above the allowed threshold. |
Rik van Riel | e4991b2 | 2015-05-27 15:04:27 -0400 | [diff] [blame] | 1227 | * Compare it with the old imbalance. |
Rik van Riel | e63da03 | 2014-05-14 13:22:21 -0400 | [diff] [blame] | 1228 | */ |
Rik van Riel | 28a21745 | 2014-06-23 11:46:13 -0400 | [diff] [blame] | 1229 | orig_src_load = env->src_stats.load; |
Rik van Riel | e4991b2 | 2015-05-27 15:04:27 -0400 | [diff] [blame] | 1230 | orig_dst_load = env->dst_stats.load; |
Rik van Riel | 28a21745 | 2014-06-23 11:46:13 -0400 | [diff] [blame] | 1231 | |
Rik van Riel | e4991b2 | 2015-05-27 15:04:27 -0400 | [diff] [blame] | 1232 | if (orig_dst_load < orig_src_load) |
| 1233 | swap(orig_dst_load, orig_src_load); |
Rik van Riel | e63da03 | 2014-05-14 13:22:21 -0400 | [diff] [blame] | 1234 | |
Rik van Riel | e4991b2 | 2015-05-27 15:04:27 -0400 | [diff] [blame] | 1235 | old_imb = orig_dst_load * src_capacity * 100 - |
| 1236 | orig_src_load * dst_capacity * env->imbalance_pct; |
| 1237 | |
| 1238 | /* Would this change make things worse? */ |
| 1239 | return (imb > old_imb); |
Rik van Riel | e63da03 | 2014-05-14 13:22:21 -0400 | [diff] [blame] | 1240 | } |
| 1241 | |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1242 | /* |
| 1243 | * This checks if the overall compute and NUMA accesses of the system would |
| 1244 | * be improved if the source tasks was migrated to the target dst_cpu taking |
| 1245 | * into account that it might be best if task running on the dst_cpu should |
| 1246 | * be exchanged with the source task |
| 1247 | */ |
Rik van Riel | 887c290 | 2013-10-07 11:29:31 +0100 | [diff] [blame] | 1248 | static void task_numa_compare(struct task_numa_env *env, |
| 1249 | long taskimp, long groupimp) |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1250 | { |
| 1251 | struct rq *src_rq = cpu_rq(env->src_cpu); |
| 1252 | struct rq *dst_rq = cpu_rq(env->dst_cpu); |
| 1253 | struct task_struct *cur; |
Rik van Riel | 28a21745 | 2014-06-23 11:46:13 -0400 | [diff] [blame] | 1254 | long src_load, dst_load; |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1255 | long load; |
Rik van Riel | 1c5d3eb | 2014-06-23 11:46:15 -0400 | [diff] [blame] | 1256 | long imp = env->p->numa_group ? groupimp : taskimp; |
Rik van Riel | 0132c3e | 2014-06-23 11:46:16 -0400 | [diff] [blame] | 1257 | long moveimp = imp; |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1258 | int dist = env->dist; |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1259 | |
| 1260 | rcu_read_lock(); |
Kirill Tkhai | 1effd9f | 2014-10-22 11:17:11 +0400 | [diff] [blame] | 1261 | |
| 1262 | raw_spin_lock_irq(&dst_rq->lock); |
| 1263 | cur = dst_rq->curr; |
| 1264 | /* |
| 1265 | * No need to move the exiting task, and this ensures that ->curr |
| 1266 | * wasn't reaped and thus get_task_struct() in task_numa_assign() |
| 1267 | * is safe under RCU read lock. |
| 1268 | * Note that rcu_read_lock() itself can't protect from the final |
| 1269 | * put_task_struct() after the last schedule(). |
| 1270 | */ |
| 1271 | if ((cur->flags & PF_EXITING) || is_idle_task(cur)) |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1272 | cur = NULL; |
Kirill Tkhai | 1effd9f | 2014-10-22 11:17:11 +0400 | [diff] [blame] | 1273 | raw_spin_unlock_irq(&dst_rq->lock); |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1274 | |
| 1275 | /* |
Peter Zijlstra | 7af6833 | 2014-11-10 10:54:35 +0100 | [diff] [blame] | 1276 | * Because we have preemption enabled we can get migrated around and |
| 1277 | * end try selecting ourselves (current == env->p) as a swap candidate. |
| 1278 | */ |
| 1279 | if (cur == env->p) |
| 1280 | goto unlock; |
| 1281 | |
| 1282 | /* |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1283 | * "imp" is the fault differential for the source task between the |
| 1284 | * source and destination node. Calculate the total differential for |
| 1285 | * the source task and potential destination task. The more negative |
| 1286 | * the value is, the more rmeote accesses that would be expected to |
| 1287 | * be incurred if the tasks were swapped. |
| 1288 | */ |
| 1289 | if (cur) { |
| 1290 | /* Skip this swap candidate if cannot move to the source cpu */ |
| 1291 | if (!cpumask_test_cpu(env->src_cpu, tsk_cpus_allowed(cur))) |
| 1292 | goto unlock; |
| 1293 | |
Rik van Riel | 887c290 | 2013-10-07 11:29:31 +0100 | [diff] [blame] | 1294 | /* |
| 1295 | * If dst and source tasks are in the same NUMA group, or not |
Rik van Riel | ca28aa53 | 2013-10-07 11:29:32 +0100 | [diff] [blame] | 1296 | * in any group then look only at task weights. |
Rik van Riel | 887c290 | 2013-10-07 11:29:31 +0100 | [diff] [blame] | 1297 | */ |
Rik van Riel | ca28aa53 | 2013-10-07 11:29:32 +0100 | [diff] [blame] | 1298 | if (cur->numa_group == env->p->numa_group) { |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1299 | imp = taskimp + task_weight(cur, env->src_nid, dist) - |
| 1300 | task_weight(cur, env->dst_nid, dist); |
Rik van Riel | ca28aa53 | 2013-10-07 11:29:32 +0100 | [diff] [blame] | 1301 | /* |
| 1302 | * Add some hysteresis to prevent swapping the |
| 1303 | * tasks within a group over tiny differences. |
| 1304 | */ |
| 1305 | if (cur->numa_group) |
| 1306 | imp -= imp/16; |
Rik van Riel | 887c290 | 2013-10-07 11:29:31 +0100 | [diff] [blame] | 1307 | } else { |
Rik van Riel | ca28aa53 | 2013-10-07 11:29:32 +0100 | [diff] [blame] | 1308 | /* |
| 1309 | * Compare the group weights. If a task is all by |
| 1310 | * itself (not part of a group), use the task weight |
| 1311 | * instead. |
| 1312 | */ |
Rik van Riel | ca28aa53 | 2013-10-07 11:29:32 +0100 | [diff] [blame] | 1313 | if (cur->numa_group) |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1314 | imp += group_weight(cur, env->src_nid, dist) - |
| 1315 | group_weight(cur, env->dst_nid, dist); |
Rik van Riel | ca28aa53 | 2013-10-07 11:29:32 +0100 | [diff] [blame] | 1316 | else |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1317 | imp += task_weight(cur, env->src_nid, dist) - |
| 1318 | task_weight(cur, env->dst_nid, dist); |
Rik van Riel | 887c290 | 2013-10-07 11:29:31 +0100 | [diff] [blame] | 1319 | } |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1320 | } |
| 1321 | |
Rik van Riel | 0132c3e | 2014-06-23 11:46:16 -0400 | [diff] [blame] | 1322 | if (imp <= env->best_imp && moveimp <= env->best_imp) |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1323 | goto unlock; |
| 1324 | |
| 1325 | if (!cur) { |
| 1326 | /* Is there capacity at our destination? */ |
Rik van Riel | b932c03 | 2014-08-04 13:23:27 -0400 | [diff] [blame] | 1327 | if (env->src_stats.nr_running <= env->src_stats.task_capacity && |
Nicolas Pitre | 1b6a749 | 2014-05-26 18:19:35 -0400 | [diff] [blame] | 1328 | !env->dst_stats.has_free_capacity) |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1329 | goto unlock; |
| 1330 | |
| 1331 | goto balance; |
| 1332 | } |
| 1333 | |
| 1334 | /* Balance doesn't matter much if we're running a task per cpu */ |
Rik van Riel | 0132c3e | 2014-06-23 11:46:16 -0400 | [diff] [blame] | 1335 | if (imp > env->best_imp && src_rq->nr_running == 1 && |
| 1336 | dst_rq->nr_running == 1) |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1337 | goto assign; |
| 1338 | |
| 1339 | /* |
| 1340 | * In the overloaded case, try and keep the load balanced. |
| 1341 | */ |
| 1342 | balance: |
Peter Zijlstra | e720fff | 2014-07-11 16:01:53 +0200 | [diff] [blame] | 1343 | load = task_h_load(env->p); |
| 1344 | dst_load = env->dst_stats.load + load; |
| 1345 | src_load = env->src_stats.load - load; |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1346 | |
Rik van Riel | 0132c3e | 2014-06-23 11:46:16 -0400 | [diff] [blame] | 1347 | if (moveimp > imp && moveimp > env->best_imp) { |
| 1348 | /* |
| 1349 | * If the improvement from just moving env->p direction is |
| 1350 | * better than swapping tasks around, check if a move is |
| 1351 | * possible. Store a slightly smaller score than moveimp, |
| 1352 | * so an actually idle CPU will win. |
| 1353 | */ |
| 1354 | if (!load_too_imbalanced(src_load, dst_load, env)) { |
| 1355 | imp = moveimp - 1; |
| 1356 | cur = NULL; |
| 1357 | goto assign; |
| 1358 | } |
| 1359 | } |
| 1360 | |
| 1361 | if (imp <= env->best_imp) |
| 1362 | goto unlock; |
| 1363 | |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1364 | if (cur) { |
Peter Zijlstra | e720fff | 2014-07-11 16:01:53 +0200 | [diff] [blame] | 1365 | load = task_h_load(cur); |
| 1366 | dst_load -= load; |
| 1367 | src_load += load; |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1368 | } |
| 1369 | |
Rik van Riel | 28a21745 | 2014-06-23 11:46:13 -0400 | [diff] [blame] | 1370 | if (load_too_imbalanced(src_load, dst_load, env)) |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1371 | goto unlock; |
| 1372 | |
Rik van Riel | ba7e5a2 | 2014-09-04 16:35:30 -0400 | [diff] [blame] | 1373 | /* |
| 1374 | * One idle CPU per node is evaluated for a task numa move. |
| 1375 | * Call select_idle_sibling to maybe find a better one. |
| 1376 | */ |
| 1377 | if (!cur) |
| 1378 | env->dst_cpu = select_idle_sibling(env->p, env->dst_cpu); |
| 1379 | |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1380 | assign: |
| 1381 | task_numa_assign(env, cur, imp); |
| 1382 | unlock: |
| 1383 | rcu_read_unlock(); |
| 1384 | } |
| 1385 | |
Rik van Riel | 887c290 | 2013-10-07 11:29:31 +0100 | [diff] [blame] | 1386 | static void task_numa_find_cpu(struct task_numa_env *env, |
| 1387 | long taskimp, long groupimp) |
Mel Gorman | 2c8a50a | 2013-10-07 11:29:18 +0100 | [diff] [blame] | 1388 | { |
| 1389 | int cpu; |
| 1390 | |
| 1391 | for_each_cpu(cpu, cpumask_of_node(env->dst_nid)) { |
| 1392 | /* Skip this CPU if the source task cannot migrate */ |
| 1393 | if (!cpumask_test_cpu(cpu, tsk_cpus_allowed(env->p))) |
| 1394 | continue; |
| 1395 | |
| 1396 | env->dst_cpu = cpu; |
Rik van Riel | 887c290 | 2013-10-07 11:29:31 +0100 | [diff] [blame] | 1397 | task_numa_compare(env, taskimp, groupimp); |
Mel Gorman | 2c8a50a | 2013-10-07 11:29:18 +0100 | [diff] [blame] | 1398 | } |
| 1399 | } |
| 1400 | |
Rik van Riel | 6f9aad0 | 2015-05-28 09:52:49 -0400 | [diff] [blame] | 1401 | /* Only move tasks to a NUMA node less busy than the current node. */ |
| 1402 | static bool numa_has_capacity(struct task_numa_env *env) |
| 1403 | { |
| 1404 | struct numa_stats *src = &env->src_stats; |
| 1405 | struct numa_stats *dst = &env->dst_stats; |
| 1406 | |
| 1407 | if (src->has_free_capacity && !dst->has_free_capacity) |
| 1408 | return false; |
| 1409 | |
| 1410 | /* |
| 1411 | * Only consider a task move if the source has a higher load |
| 1412 | * than the destination, corrected for CPU capacity on each node. |
| 1413 | * |
| 1414 | * src->load dst->load |
| 1415 | * --------------------- vs --------------------- |
| 1416 | * src->compute_capacity dst->compute_capacity |
| 1417 | */ |
| 1418 | if (src->load * dst->compute_capacity > |
| 1419 | dst->load * src->compute_capacity) |
| 1420 | return true; |
| 1421 | |
| 1422 | return false; |
| 1423 | } |
| 1424 | |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1425 | static int task_numa_migrate(struct task_struct *p) |
Mel Gorman | e6628d5 | 2013-10-07 11:29:02 +0100 | [diff] [blame] | 1426 | { |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1427 | struct task_numa_env env = { |
| 1428 | .p = p, |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1429 | |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1430 | .src_cpu = task_cpu(p), |
Ingo Molnar | b32e86b | 2013-10-07 11:29:30 +0100 | [diff] [blame] | 1431 | .src_nid = task_node(p), |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1432 | |
| 1433 | .imbalance_pct = 112, |
| 1434 | |
| 1435 | .best_task = NULL, |
| 1436 | .best_imp = 0, |
| 1437 | .best_cpu = -1 |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1438 | }; |
| 1439 | struct sched_domain *sd; |
Rik van Riel | 887c290 | 2013-10-07 11:29:31 +0100 | [diff] [blame] | 1440 | unsigned long taskweight, groupweight; |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1441 | int nid, ret, dist; |
Rik van Riel | 887c290 | 2013-10-07 11:29:31 +0100 | [diff] [blame] | 1442 | long taskimp, groupimp; |
Mel Gorman | e6628d5 | 2013-10-07 11:29:02 +0100 | [diff] [blame] | 1443 | |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1444 | /* |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1445 | * Pick the lowest SD_NUMA domain, as that would have the smallest |
| 1446 | * imbalance and would be the first to start moving tasks about. |
| 1447 | * |
| 1448 | * And we want to avoid any moving of tasks about, as that would create |
| 1449 | * random movement of tasks -- counter the numa conditions we're trying |
| 1450 | * to satisfy here. |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1451 | */ |
Mel Gorman | e6628d5 | 2013-10-07 11:29:02 +0100 | [diff] [blame] | 1452 | rcu_read_lock(); |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1453 | sd = rcu_dereference(per_cpu(sd_numa, env.src_cpu)); |
Rik van Riel | 46a73e8 | 2013-11-11 19:29:25 -0500 | [diff] [blame] | 1454 | if (sd) |
| 1455 | env.imbalance_pct = 100 + (sd->imbalance_pct - 100) / 2; |
Mel Gorman | e6628d5 | 2013-10-07 11:29:02 +0100 | [diff] [blame] | 1456 | rcu_read_unlock(); |
| 1457 | |
Rik van Riel | 46a73e8 | 2013-11-11 19:29:25 -0500 | [diff] [blame] | 1458 | /* |
| 1459 | * Cpusets can break the scheduler domain tree into smaller |
| 1460 | * balance domains, some of which do not cross NUMA boundaries. |
| 1461 | * Tasks that are "trapped" in such domains cannot be migrated |
| 1462 | * elsewhere, so there is no point in (re)trying. |
| 1463 | */ |
| 1464 | if (unlikely(!sd)) { |
Wanpeng Li | de1b301 | 2013-12-12 15:23:24 +0800 | [diff] [blame] | 1465 | p->numa_preferred_nid = task_node(p); |
Rik van Riel | 46a73e8 | 2013-11-11 19:29:25 -0500 | [diff] [blame] | 1466 | return -EINVAL; |
| 1467 | } |
| 1468 | |
Mel Gorman | 2c8a50a | 2013-10-07 11:29:18 +0100 | [diff] [blame] | 1469 | env.dst_nid = p->numa_preferred_nid; |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1470 | dist = env.dist = node_distance(env.src_nid, env.dst_nid); |
| 1471 | taskweight = task_weight(p, env.src_nid, dist); |
| 1472 | groupweight = group_weight(p, env.src_nid, dist); |
| 1473 | update_numa_stats(&env.src_stats, env.src_nid); |
| 1474 | taskimp = task_weight(p, env.dst_nid, dist) - taskweight; |
| 1475 | groupimp = group_weight(p, env.dst_nid, dist) - groupweight; |
Mel Gorman | 2c8a50a | 2013-10-07 11:29:18 +0100 | [diff] [blame] | 1476 | update_numa_stats(&env.dst_stats, env.dst_nid); |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1477 | |
Rik van Riel | a43455a | 2014-06-04 16:09:42 -0400 | [diff] [blame] | 1478 | /* Try to find a spot on the preferred nid. */ |
Rik van Riel | 6f9aad0 | 2015-05-28 09:52:49 -0400 | [diff] [blame] | 1479 | if (numa_has_capacity(&env)) |
| 1480 | task_numa_find_cpu(&env, taskimp, groupimp); |
Rik van Riel | e1dda8a | 2013-10-07 11:29:19 +0100 | [diff] [blame] | 1481 | |
Rik van Riel | 9de05d4 | 2014-10-09 17:27:47 -0400 | [diff] [blame] | 1482 | /* |
| 1483 | * Look at other nodes in these cases: |
| 1484 | * - there is no space available on the preferred_nid |
| 1485 | * - the task is part of a numa_group that is interleaved across |
| 1486 | * multiple NUMA nodes; in order to better consolidate the group, |
| 1487 | * we need to check other locations. |
| 1488 | */ |
| 1489 | if (env.best_cpu == -1 || (p->numa_group && |
| 1490 | nodes_weight(p->numa_group->active_nodes) > 1)) { |
Mel Gorman | 2c8a50a | 2013-10-07 11:29:18 +0100 | [diff] [blame] | 1491 | for_each_online_node(nid) { |
| 1492 | if (nid == env.src_nid || nid == p->numa_preferred_nid) |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1493 | continue; |
| 1494 | |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1495 | dist = node_distance(env.src_nid, env.dst_nid); |
Rik van Riel | 6c6b119 | 2014-10-17 03:29:52 -0400 | [diff] [blame] | 1496 | if (sched_numa_topology_type == NUMA_BACKPLANE && |
| 1497 | dist != env.dist) { |
| 1498 | taskweight = task_weight(p, env.src_nid, dist); |
| 1499 | groupweight = group_weight(p, env.src_nid, dist); |
| 1500 | } |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1501 | |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 1502 | /* Only consider nodes where both task and groups benefit */ |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1503 | taskimp = task_weight(p, nid, dist) - taskweight; |
| 1504 | groupimp = group_weight(p, nid, dist) - groupweight; |
Rik van Riel | 887c290 | 2013-10-07 11:29:31 +0100 | [diff] [blame] | 1505 | if (taskimp < 0 && groupimp < 0) |
Mel Gorman | 2c8a50a | 2013-10-07 11:29:18 +0100 | [diff] [blame] | 1506 | continue; |
| 1507 | |
Rik van Riel | 7bd9532 | 2014-10-17 03:29:51 -0400 | [diff] [blame] | 1508 | env.dist = dist; |
Mel Gorman | 2c8a50a | 2013-10-07 11:29:18 +0100 | [diff] [blame] | 1509 | env.dst_nid = nid; |
| 1510 | update_numa_stats(&env.dst_stats, env.dst_nid); |
Rik van Riel | 6f9aad0 | 2015-05-28 09:52:49 -0400 | [diff] [blame] | 1511 | if (numa_has_capacity(&env)) |
| 1512 | task_numa_find_cpu(&env, taskimp, groupimp); |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 1513 | } |
| 1514 | } |
| 1515 | |
Rik van Riel | 68d1b02 | 2014-04-11 13:00:29 -0400 | [diff] [blame] | 1516 | /* |
| 1517 | * If the task is part of a workload that spans multiple NUMA nodes, |
| 1518 | * and is migrating into one of the workload's active nodes, remember |
| 1519 | * this node as the task's preferred numa node, so the workload can |
| 1520 | * settle down. |
| 1521 | * A task that migrated to a second choice node will be better off |
| 1522 | * trying for a better one later. Do not set the preferred node here. |
| 1523 | */ |
Rik van Riel | db015da | 2014-06-23 11:41:34 -0400 | [diff] [blame] | 1524 | if (p->numa_group) { |
| 1525 | if (env.best_cpu == -1) |
| 1526 | nid = env.src_nid; |
| 1527 | else |
| 1528 | nid = env.dst_nid; |
| 1529 | |
| 1530 | if (node_isset(nid, p->numa_group->active_nodes)) |
| 1531 | sched_setnuma(p, env.dst_nid); |
| 1532 | } |
| 1533 | |
| 1534 | /* No better CPU than the current one was found. */ |
| 1535 | if (env.best_cpu == -1) |
| 1536 | return -EAGAIN; |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 1537 | |
Rik van Riel | 04bb2f9 | 2013-10-07 11:29:36 +0100 | [diff] [blame] | 1538 | /* |
| 1539 | * Reset the scan period if the task is being rescheduled on an |
| 1540 | * alternative node to recheck if the tasks is now properly placed. |
| 1541 | */ |
| 1542 | p->numa_scan_period = task_scan_min(p); |
| 1543 | |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1544 | if (env.best_task == NULL) { |
Mel Gorman | 286549d | 2014-01-21 15:51:03 -0800 | [diff] [blame] | 1545 | ret = migrate_task_to(p, env.best_cpu); |
| 1546 | if (ret != 0) |
| 1547 | trace_sched_stick_numa(p, env.src_cpu, env.best_cpu); |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1548 | return ret; |
| 1549 | } |
| 1550 | |
| 1551 | ret = migrate_swap(p, env.best_task); |
Mel Gorman | 286549d | 2014-01-21 15:51:03 -0800 | [diff] [blame] | 1552 | if (ret != 0) |
| 1553 | trace_sched_stick_numa(p, env.src_cpu, task_cpu(env.best_task)); |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1554 | put_task_struct(env.best_task); |
| 1555 | return ret; |
Mel Gorman | e6628d5 | 2013-10-07 11:29:02 +0100 | [diff] [blame] | 1556 | } |
| 1557 | |
Mel Gorman | 6b9a746 | 2013-10-07 11:29:11 +0100 | [diff] [blame] | 1558 | /* Attempt to migrate a task to a CPU on the preferred node. */ |
| 1559 | static void numa_migrate_preferred(struct task_struct *p) |
| 1560 | { |
Rik van Riel | 5085e2a | 2014-04-11 13:00:28 -0400 | [diff] [blame] | 1561 | unsigned long interval = HZ; |
| 1562 | |
Rik van Riel | 2739d3e | 2013-10-07 11:29:41 +0100 | [diff] [blame] | 1563 | /* This task has no NUMA fault statistics yet */ |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 1564 | if (unlikely(p->numa_preferred_nid == -1 || !p->numa_faults)) |
Rik van Riel | 2739d3e | 2013-10-07 11:29:41 +0100 | [diff] [blame] | 1565 | return; |
| 1566 | |
| 1567 | /* Periodically retry migrating the task to the preferred node */ |
Rik van Riel | 5085e2a | 2014-04-11 13:00:28 -0400 | [diff] [blame] | 1568 | interval = min(interval, msecs_to_jiffies(p->numa_scan_period) / 16); |
| 1569 | p->numa_migrate_retry = jiffies + interval; |
Rik van Riel | 2739d3e | 2013-10-07 11:29:41 +0100 | [diff] [blame] | 1570 | |
Mel Gorman | 6b9a746 | 2013-10-07 11:29:11 +0100 | [diff] [blame] | 1571 | /* Success if task is already running on preferred CPU */ |
Wanpeng Li | de1b301 | 2013-12-12 15:23:24 +0800 | [diff] [blame] | 1572 | if (task_node(p) == p->numa_preferred_nid) |
Mel Gorman | 6b9a746 | 2013-10-07 11:29:11 +0100 | [diff] [blame] | 1573 | return; |
| 1574 | |
Mel Gorman | 6b9a746 | 2013-10-07 11:29:11 +0100 | [diff] [blame] | 1575 | /* Otherwise, try migrate to a CPU on the preferred node */ |
Rik van Riel | 2739d3e | 2013-10-07 11:29:41 +0100 | [diff] [blame] | 1576 | task_numa_migrate(p); |
Mel Gorman | 6b9a746 | 2013-10-07 11:29:11 +0100 | [diff] [blame] | 1577 | } |
| 1578 | |
Rik van Riel | 04bb2f9 | 2013-10-07 11:29:36 +0100 | [diff] [blame] | 1579 | /* |
Rik van Riel | 20e07de | 2014-01-27 17:03:43 -0500 | [diff] [blame] | 1580 | * Find the nodes on which the workload is actively running. We do this by |
| 1581 | * tracking the nodes from which NUMA hinting faults are triggered. This can |
| 1582 | * be different from the set of nodes where the workload's memory is currently |
| 1583 | * located. |
| 1584 | * |
| 1585 | * The bitmask is used to make smarter decisions on when to do NUMA page |
| 1586 | * migrations, To prevent flip-flopping, and excessive page migrations, nodes |
| 1587 | * are added when they cause over 6/16 of the maximum number of faults, but |
| 1588 | * only removed when they drop below 3/16. |
| 1589 | */ |
| 1590 | static void update_numa_active_node_mask(struct numa_group *numa_group) |
| 1591 | { |
| 1592 | unsigned long faults, max_faults = 0; |
| 1593 | int nid; |
| 1594 | |
| 1595 | for_each_online_node(nid) { |
| 1596 | faults = group_faults_cpu(numa_group, nid); |
| 1597 | if (faults > max_faults) |
| 1598 | max_faults = faults; |
| 1599 | } |
| 1600 | |
| 1601 | for_each_online_node(nid) { |
| 1602 | faults = group_faults_cpu(numa_group, nid); |
| 1603 | if (!node_isset(nid, numa_group->active_nodes)) { |
| 1604 | if (faults > max_faults * 6 / 16) |
| 1605 | node_set(nid, numa_group->active_nodes); |
| 1606 | } else if (faults < max_faults * 3 / 16) |
| 1607 | node_clear(nid, numa_group->active_nodes); |
| 1608 | } |
| 1609 | } |
| 1610 | |
| 1611 | /* |
Rik van Riel | 04bb2f9 | 2013-10-07 11:29:36 +0100 | [diff] [blame] | 1612 | * When adapting the scan rate, the period is divided into NUMA_PERIOD_SLOTS |
| 1613 | * increments. The more local the fault statistics are, the higher the scan |
Rik van Riel | a22b4b01 | 2014-06-23 11:41:35 -0400 | [diff] [blame] | 1614 | * period will be for the next scan window. If local/(local+remote) ratio is |
| 1615 | * below NUMA_PERIOD_THRESHOLD (where range of ratio is 1..NUMA_PERIOD_SLOTS) |
| 1616 | * the scan period will decrease. Aim for 70% local accesses. |
Rik van Riel | 04bb2f9 | 2013-10-07 11:29:36 +0100 | [diff] [blame] | 1617 | */ |
| 1618 | #define NUMA_PERIOD_SLOTS 10 |
Rik van Riel | a22b4b01 | 2014-06-23 11:41:35 -0400 | [diff] [blame] | 1619 | #define NUMA_PERIOD_THRESHOLD 7 |
Rik van Riel | 04bb2f9 | 2013-10-07 11:29:36 +0100 | [diff] [blame] | 1620 | |
| 1621 | /* |
| 1622 | * Increase the scan period (slow down scanning) if the majority of |
| 1623 | * our memory is already on our local node, or if the majority of |
| 1624 | * the page accesses are shared with other processes. |
| 1625 | * Otherwise, decrease the scan period. |
| 1626 | */ |
| 1627 | static void update_task_scan_period(struct task_struct *p, |
| 1628 | unsigned long shared, unsigned long private) |
| 1629 | { |
| 1630 | unsigned int period_slot; |
| 1631 | int ratio; |
| 1632 | int diff; |
| 1633 | |
| 1634 | unsigned long remote = p->numa_faults_locality[0]; |
| 1635 | unsigned long local = p->numa_faults_locality[1]; |
| 1636 | |
| 1637 | /* |
| 1638 | * If there were no record hinting faults then either the task is |
| 1639 | * completely idle or all activity is areas that are not of interest |
Mel Gorman | 074c238 | 2015-03-25 15:55:42 -0700 | [diff] [blame] | 1640 | * to automatic numa balancing. Related to that, if there were failed |
| 1641 | * migration then it implies we are migrating too quickly or the local |
| 1642 | * node is overloaded. In either case, scan slower |
Rik van Riel | 04bb2f9 | 2013-10-07 11:29:36 +0100 | [diff] [blame] | 1643 | */ |
Mel Gorman | 074c238 | 2015-03-25 15:55:42 -0700 | [diff] [blame] | 1644 | if (local + shared == 0 || p->numa_faults_locality[2]) { |
Rik van Riel | 04bb2f9 | 2013-10-07 11:29:36 +0100 | [diff] [blame] | 1645 | p->numa_scan_period = min(p->numa_scan_period_max, |
| 1646 | p->numa_scan_period << 1); |
| 1647 | |
| 1648 | p->mm->numa_next_scan = jiffies + |
| 1649 | msecs_to_jiffies(p->numa_scan_period); |
| 1650 | |
| 1651 | return; |
| 1652 | } |
| 1653 | |
| 1654 | /* |
| 1655 | * Prepare to scale scan period relative to the current period. |
| 1656 | * == NUMA_PERIOD_THRESHOLD scan period stays the same |
| 1657 | * < NUMA_PERIOD_THRESHOLD scan period decreases (scan faster) |
| 1658 | * >= NUMA_PERIOD_THRESHOLD scan period increases (scan slower) |
| 1659 | */ |
| 1660 | period_slot = DIV_ROUND_UP(p->numa_scan_period, NUMA_PERIOD_SLOTS); |
| 1661 | ratio = (local * NUMA_PERIOD_SLOTS) / (local + remote); |
| 1662 | if (ratio >= NUMA_PERIOD_THRESHOLD) { |
| 1663 | int slot = ratio - NUMA_PERIOD_THRESHOLD; |
| 1664 | if (!slot) |
| 1665 | slot = 1; |
| 1666 | diff = slot * period_slot; |
| 1667 | } else { |
| 1668 | diff = -(NUMA_PERIOD_THRESHOLD - ratio) * period_slot; |
| 1669 | |
| 1670 | /* |
| 1671 | * Scale scan rate increases based on sharing. There is an |
| 1672 | * inverse relationship between the degree of sharing and |
| 1673 | * the adjustment made to the scanning period. Broadly |
| 1674 | * speaking the intent is that there is little point |
| 1675 | * scanning faster if shared accesses dominate as it may |
| 1676 | * simply bounce migrations uselessly |
| 1677 | */ |
Yasuaki Ishimatsu | 2847c90 | 2014-10-22 16:04:35 +0900 | [diff] [blame] | 1678 | ratio = DIV_ROUND_UP(private * NUMA_PERIOD_SLOTS, (private + shared + 1)); |
Rik van Riel | 04bb2f9 | 2013-10-07 11:29:36 +0100 | [diff] [blame] | 1679 | diff = (diff * ratio) / NUMA_PERIOD_SLOTS; |
| 1680 | } |
| 1681 | |
| 1682 | p->numa_scan_period = clamp(p->numa_scan_period + diff, |
| 1683 | task_scan_min(p), task_scan_max(p)); |
| 1684 | memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality)); |
| 1685 | } |
| 1686 | |
Rik van Riel | 7e2703e | 2014-01-27 17:03:45 -0500 | [diff] [blame] | 1687 | /* |
| 1688 | * Get the fraction of time the task has been running since the last |
| 1689 | * NUMA placement cycle. The scheduler keeps similar statistics, but |
| 1690 | * decays those on a 32ms period, which is orders of magnitude off |
| 1691 | * from the dozens-of-seconds NUMA balancing period. Use the scheduler |
| 1692 | * stats only if the task is so new there are no NUMA statistics yet. |
| 1693 | */ |
| 1694 | static u64 numa_get_avg_runtime(struct task_struct *p, u64 *period) |
| 1695 | { |
| 1696 | u64 runtime, delta, now; |
| 1697 | /* Use the start of this time slice to avoid calculations. */ |
| 1698 | now = p->se.exec_start; |
| 1699 | runtime = p->se.sum_exec_runtime; |
| 1700 | |
| 1701 | if (p->last_task_numa_placement) { |
| 1702 | delta = runtime - p->last_sum_exec_runtime; |
| 1703 | *period = now - p->last_task_numa_placement; |
| 1704 | } else { |
| 1705 | delta = p->se.avg.runnable_avg_sum; |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 1706 | *period = p->se.avg.avg_period; |
Rik van Riel | 7e2703e | 2014-01-27 17:03:45 -0500 | [diff] [blame] | 1707 | } |
| 1708 | |
| 1709 | p->last_sum_exec_runtime = runtime; |
| 1710 | p->last_task_numa_placement = now; |
| 1711 | |
| 1712 | return delta; |
| 1713 | } |
| 1714 | |
Rik van Riel | 5400941 | 2014-10-17 03:29:53 -0400 | [diff] [blame] | 1715 | /* |
| 1716 | * Determine the preferred nid for a task in a numa_group. This needs to |
| 1717 | * be done in a way that produces consistent results with group_weight, |
| 1718 | * otherwise workloads might not converge. |
| 1719 | */ |
| 1720 | static int preferred_group_nid(struct task_struct *p, int nid) |
| 1721 | { |
| 1722 | nodemask_t nodes; |
| 1723 | int dist; |
| 1724 | |
| 1725 | /* Direct connections between all NUMA nodes. */ |
| 1726 | if (sched_numa_topology_type == NUMA_DIRECT) |
| 1727 | return nid; |
| 1728 | |
| 1729 | /* |
| 1730 | * On a system with glueless mesh NUMA topology, group_weight |
| 1731 | * scores nodes according to the number of NUMA hinting faults on |
| 1732 | * both the node itself, and on nearby nodes. |
| 1733 | */ |
| 1734 | if (sched_numa_topology_type == NUMA_GLUELESS_MESH) { |
| 1735 | unsigned long score, max_score = 0; |
| 1736 | int node, max_node = nid; |
| 1737 | |
| 1738 | dist = sched_max_numa_distance; |
| 1739 | |
| 1740 | for_each_online_node(node) { |
| 1741 | score = group_weight(p, node, dist); |
| 1742 | if (score > max_score) { |
| 1743 | max_score = score; |
| 1744 | max_node = node; |
| 1745 | } |
| 1746 | } |
| 1747 | return max_node; |
| 1748 | } |
| 1749 | |
| 1750 | /* |
| 1751 | * Finding the preferred nid in a system with NUMA backplane |
| 1752 | * interconnect topology is more involved. The goal is to locate |
| 1753 | * tasks from numa_groups near each other in the system, and |
| 1754 | * untangle workloads from different sides of the system. This requires |
| 1755 | * searching down the hierarchy of node groups, recursively searching |
| 1756 | * inside the highest scoring group of nodes. The nodemask tricks |
| 1757 | * keep the complexity of the search down. |
| 1758 | */ |
| 1759 | nodes = node_online_map; |
| 1760 | for (dist = sched_max_numa_distance; dist > LOCAL_DISTANCE; dist--) { |
| 1761 | unsigned long max_faults = 0; |
Jan Beulich | 8190747 | 2015-01-23 08:25:38 +0000 | [diff] [blame] | 1762 | nodemask_t max_group = NODE_MASK_NONE; |
Rik van Riel | 5400941 | 2014-10-17 03:29:53 -0400 | [diff] [blame] | 1763 | int a, b; |
| 1764 | |
| 1765 | /* Are there nodes at this distance from each other? */ |
| 1766 | if (!find_numa_distance(dist)) |
| 1767 | continue; |
| 1768 | |
| 1769 | for_each_node_mask(a, nodes) { |
| 1770 | unsigned long faults = 0; |
| 1771 | nodemask_t this_group; |
| 1772 | nodes_clear(this_group); |
| 1773 | |
| 1774 | /* Sum group's NUMA faults; includes a==b case. */ |
| 1775 | for_each_node_mask(b, nodes) { |
| 1776 | if (node_distance(a, b) < dist) { |
| 1777 | faults += group_faults(p, b); |
| 1778 | node_set(b, this_group); |
| 1779 | node_clear(b, nodes); |
| 1780 | } |
| 1781 | } |
| 1782 | |
| 1783 | /* Remember the top group. */ |
| 1784 | if (faults > max_faults) { |
| 1785 | max_faults = faults; |
| 1786 | max_group = this_group; |
| 1787 | /* |
| 1788 | * subtle: at the smallest distance there is |
| 1789 | * just one node left in each "group", the |
| 1790 | * winner is the preferred nid. |
| 1791 | */ |
| 1792 | nid = a; |
| 1793 | } |
| 1794 | } |
| 1795 | /* Next round, evaluate the nodes within max_group. */ |
Jan Beulich | 890a540 | 2015-02-09 12:30:00 +0100 | [diff] [blame] | 1796 | if (!max_faults) |
| 1797 | break; |
Rik van Riel | 5400941 | 2014-10-17 03:29:53 -0400 | [diff] [blame] | 1798 | nodes = max_group; |
| 1799 | } |
| 1800 | return nid; |
| 1801 | } |
| 1802 | |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 1803 | static void task_numa_placement(struct task_struct *p) |
| 1804 | { |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 1805 | int seq, nid, max_nid = -1, max_group_nid = -1; |
| 1806 | unsigned long max_faults = 0, max_group_faults = 0; |
Rik van Riel | 04bb2f9 | 2013-10-07 11:29:36 +0100 | [diff] [blame] | 1807 | unsigned long fault_types[2] = { 0, 0 }; |
Rik van Riel | 7e2703e | 2014-01-27 17:03:45 -0500 | [diff] [blame] | 1808 | unsigned long total_faults; |
| 1809 | u64 runtime, period; |
Mel Gorman | 7dbd13e | 2013-10-07 11:29:29 +0100 | [diff] [blame] | 1810 | spinlock_t *group_lock = NULL; |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 1811 | |
Jason Low | 7e5a2c1 | 2015-04-30 17:28:14 -0700 | [diff] [blame] | 1812 | /* |
| 1813 | * The p->mm->numa_scan_seq field gets updated without |
| 1814 | * exclusive access. Use READ_ONCE() here to ensure |
| 1815 | * that the field is read in a single access: |
| 1816 | */ |
Jason Low | 316c1608d | 2015-04-28 13:00:20 -0700 | [diff] [blame] | 1817 | seq = READ_ONCE(p->mm->numa_scan_seq); |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 1818 | if (p->numa_scan_seq == seq) |
| 1819 | return; |
| 1820 | p->numa_scan_seq = seq; |
Mel Gorman | 598f0ec | 2013-10-07 11:28:55 +0100 | [diff] [blame] | 1821 | p->numa_scan_period_max = task_scan_max(p); |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 1822 | |
Rik van Riel | 7e2703e | 2014-01-27 17:03:45 -0500 | [diff] [blame] | 1823 | total_faults = p->numa_faults_locality[0] + |
| 1824 | p->numa_faults_locality[1]; |
| 1825 | runtime = numa_get_avg_runtime(p, &period); |
| 1826 | |
Mel Gorman | 7dbd13e | 2013-10-07 11:29:29 +0100 | [diff] [blame] | 1827 | /* If the task is part of a group prevent parallel updates to group stats */ |
| 1828 | if (p->numa_group) { |
| 1829 | group_lock = &p->numa_group->lock; |
Mike Galbraith | 60e69ee | 2014-04-07 10:55:15 +0200 | [diff] [blame] | 1830 | spin_lock_irq(group_lock); |
Mel Gorman | 7dbd13e | 2013-10-07 11:29:29 +0100 | [diff] [blame] | 1831 | } |
| 1832 | |
Mel Gorman | 688b758 | 2013-10-07 11:28:58 +0100 | [diff] [blame] | 1833 | /* Find the node with the highest number of faults */ |
| 1834 | for_each_online_node(nid) { |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 1835 | /* Keep track of the offsets in numa_faults array */ |
| 1836 | int mem_idx, membuf_idx, cpu_idx, cpubuf_idx; |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 1837 | unsigned long faults = 0, group_faults = 0; |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 1838 | int priv; |
Mel Gorman | 745d614 | 2013-10-07 11:28:59 +0100 | [diff] [blame] | 1839 | |
Rik van Riel | be1e4e7 | 2014-01-27 17:03:48 -0500 | [diff] [blame] | 1840 | for (priv = 0; priv < NR_NUMA_HINT_FAULT_TYPES; priv++) { |
Rik van Riel | 7e2703e | 2014-01-27 17:03:45 -0500 | [diff] [blame] | 1841 | long diff, f_diff, f_weight; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1842 | |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 1843 | mem_idx = task_faults_idx(NUMA_MEM, nid, priv); |
| 1844 | membuf_idx = task_faults_idx(NUMA_MEMBUF, nid, priv); |
| 1845 | cpu_idx = task_faults_idx(NUMA_CPU, nid, priv); |
| 1846 | cpubuf_idx = task_faults_idx(NUMA_CPUBUF, nid, priv); |
Mel Gorman | 745d614 | 2013-10-07 11:28:59 +0100 | [diff] [blame] | 1847 | |
Mel Gorman | ac8e895 | 2013-10-07 11:29:03 +0100 | [diff] [blame] | 1848 | /* Decay existing window, copy faults since last scan */ |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 1849 | diff = p->numa_faults[membuf_idx] - p->numa_faults[mem_idx] / 2; |
| 1850 | fault_types[priv] += p->numa_faults[membuf_idx]; |
| 1851 | p->numa_faults[membuf_idx] = 0; |
Mel Gorman | fb13c7e | 2013-10-07 11:29:17 +0100 | [diff] [blame] | 1852 | |
Rik van Riel | 7e2703e | 2014-01-27 17:03:45 -0500 | [diff] [blame] | 1853 | /* |
| 1854 | * Normalize the faults_from, so all tasks in a group |
| 1855 | * count according to CPU use, instead of by the raw |
| 1856 | * number of faults. Tasks with little runtime have |
| 1857 | * little over-all impact on throughput, and thus their |
| 1858 | * faults are less important. |
| 1859 | */ |
| 1860 | f_weight = div64_u64(runtime << 16, period + 1); |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 1861 | f_weight = (f_weight * p->numa_faults[cpubuf_idx]) / |
Rik van Riel | 7e2703e | 2014-01-27 17:03:45 -0500 | [diff] [blame] | 1862 | (total_faults + 1); |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 1863 | f_diff = f_weight - p->numa_faults[cpu_idx] / 2; |
| 1864 | p->numa_faults[cpubuf_idx] = 0; |
Rik van Riel | 50ec8a4 | 2014-01-27 17:03:42 -0500 | [diff] [blame] | 1865 | |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 1866 | p->numa_faults[mem_idx] += diff; |
| 1867 | p->numa_faults[cpu_idx] += f_diff; |
| 1868 | faults += p->numa_faults[mem_idx]; |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 1869 | p->total_numa_faults += diff; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1870 | if (p->numa_group) { |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 1871 | /* |
| 1872 | * safe because we can only change our own group |
| 1873 | * |
| 1874 | * mem_idx represents the offset for a given |
| 1875 | * nid and priv in a specific region because it |
| 1876 | * is at the beginning of the numa_faults array. |
| 1877 | */ |
| 1878 | p->numa_group->faults[mem_idx] += diff; |
| 1879 | p->numa_group->faults_cpu[mem_idx] += f_diff; |
Mel Gorman | 989348b | 2013-10-07 11:29:40 +0100 | [diff] [blame] | 1880 | p->numa_group->total_faults += diff; |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 1881 | group_faults += p->numa_group->faults[mem_idx]; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1882 | } |
Mel Gorman | ac8e895 | 2013-10-07 11:29:03 +0100 | [diff] [blame] | 1883 | } |
| 1884 | |
Mel Gorman | 688b758 | 2013-10-07 11:28:58 +0100 | [diff] [blame] | 1885 | if (faults > max_faults) { |
| 1886 | max_faults = faults; |
| 1887 | max_nid = nid; |
| 1888 | } |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 1889 | |
| 1890 | if (group_faults > max_group_faults) { |
| 1891 | max_group_faults = group_faults; |
| 1892 | max_group_nid = nid; |
| 1893 | } |
| 1894 | } |
| 1895 | |
Rik van Riel | 04bb2f9 | 2013-10-07 11:29:36 +0100 | [diff] [blame] | 1896 | update_task_scan_period(p, fault_types[0], fault_types[1]); |
| 1897 | |
Mel Gorman | 7dbd13e | 2013-10-07 11:29:29 +0100 | [diff] [blame] | 1898 | if (p->numa_group) { |
Rik van Riel | 20e07de | 2014-01-27 17:03:43 -0500 | [diff] [blame] | 1899 | update_numa_active_node_mask(p->numa_group); |
Mike Galbraith | 60e69ee | 2014-04-07 10:55:15 +0200 | [diff] [blame] | 1900 | spin_unlock_irq(group_lock); |
Rik van Riel | 5400941 | 2014-10-17 03:29:53 -0400 | [diff] [blame] | 1901 | max_nid = preferred_group_nid(p, max_group_nid); |
Mel Gorman | 688b758 | 2013-10-07 11:28:58 +0100 | [diff] [blame] | 1902 | } |
| 1903 | |
Rik van Riel | bb97fc3 | 2014-06-04 16:33:15 -0400 | [diff] [blame] | 1904 | if (max_faults) { |
| 1905 | /* Set the new preferred node */ |
| 1906 | if (max_nid != p->numa_preferred_nid) |
| 1907 | sched_setnuma(p, max_nid); |
| 1908 | |
| 1909 | if (task_node(p) != p->numa_preferred_nid) |
| 1910 | numa_migrate_preferred(p); |
Mel Gorman | 3a7053b | 2013-10-07 11:29:00 +0100 | [diff] [blame] | 1911 | } |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 1912 | } |
| 1913 | |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1914 | static inline int get_numa_group(struct numa_group *grp) |
| 1915 | { |
| 1916 | return atomic_inc_not_zero(&grp->refcount); |
| 1917 | } |
| 1918 | |
| 1919 | static inline void put_numa_group(struct numa_group *grp) |
| 1920 | { |
| 1921 | if (atomic_dec_and_test(&grp->refcount)) |
| 1922 | kfree_rcu(grp, rcu); |
| 1923 | } |
| 1924 | |
Mel Gorman | 3e6a941 | 2013-10-07 11:29:35 +0100 | [diff] [blame] | 1925 | static void task_numa_group(struct task_struct *p, int cpupid, int flags, |
| 1926 | int *priv) |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1927 | { |
| 1928 | struct numa_group *grp, *my_grp; |
| 1929 | struct task_struct *tsk; |
| 1930 | bool join = false; |
| 1931 | int cpu = cpupid_to_cpu(cpupid); |
| 1932 | int i; |
| 1933 | |
| 1934 | if (unlikely(!p->numa_group)) { |
| 1935 | unsigned int size = sizeof(struct numa_group) + |
Rik van Riel | 50ec8a4 | 2014-01-27 17:03:42 -0500 | [diff] [blame] | 1936 | 4*nr_node_ids*sizeof(unsigned long); |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1937 | |
| 1938 | grp = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); |
| 1939 | if (!grp) |
| 1940 | return; |
| 1941 | |
| 1942 | atomic_set(&grp->refcount, 1); |
| 1943 | spin_lock_init(&grp->lock); |
Mel Gorman | e29cf08 | 2013-10-07 11:29:22 +0100 | [diff] [blame] | 1944 | grp->gid = p->pid; |
Rik van Riel | 50ec8a4 | 2014-01-27 17:03:42 -0500 | [diff] [blame] | 1945 | /* Second half of the array tracks nids where faults happen */ |
Rik van Riel | be1e4e7 | 2014-01-27 17:03:48 -0500 | [diff] [blame] | 1946 | grp->faults_cpu = grp->faults + NR_NUMA_HINT_FAULT_TYPES * |
| 1947 | nr_node_ids; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1948 | |
Rik van Riel | 20e07de | 2014-01-27 17:03:43 -0500 | [diff] [blame] | 1949 | node_set(task_node(current), grp->active_nodes); |
| 1950 | |
Rik van Riel | be1e4e7 | 2014-01-27 17:03:48 -0500 | [diff] [blame] | 1951 | for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 1952 | grp->faults[i] = p->numa_faults[i]; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1953 | |
Mel Gorman | 989348b | 2013-10-07 11:29:40 +0100 | [diff] [blame] | 1954 | grp->total_faults = p->total_numa_faults; |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 1955 | |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1956 | grp->nr_tasks++; |
| 1957 | rcu_assign_pointer(p->numa_group, grp); |
| 1958 | } |
| 1959 | |
| 1960 | rcu_read_lock(); |
Jason Low | 316c1608d | 2015-04-28 13:00:20 -0700 | [diff] [blame] | 1961 | tsk = READ_ONCE(cpu_rq(cpu)->curr); |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1962 | |
| 1963 | if (!cpupid_match_pid(tsk, cpupid)) |
Peter Zijlstra | 3354781 | 2013-10-09 10:24:48 +0200 | [diff] [blame] | 1964 | goto no_join; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1965 | |
| 1966 | grp = rcu_dereference(tsk->numa_group); |
| 1967 | if (!grp) |
Peter Zijlstra | 3354781 | 2013-10-09 10:24:48 +0200 | [diff] [blame] | 1968 | goto no_join; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1969 | |
| 1970 | my_grp = p->numa_group; |
| 1971 | if (grp == my_grp) |
Peter Zijlstra | 3354781 | 2013-10-09 10:24:48 +0200 | [diff] [blame] | 1972 | goto no_join; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1973 | |
| 1974 | /* |
| 1975 | * Only join the other group if its bigger; if we're the bigger group, |
| 1976 | * the other task will join us. |
| 1977 | */ |
| 1978 | if (my_grp->nr_tasks > grp->nr_tasks) |
Peter Zijlstra | 3354781 | 2013-10-09 10:24:48 +0200 | [diff] [blame] | 1979 | goto no_join; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1980 | |
| 1981 | /* |
| 1982 | * Tie-break on the grp address. |
| 1983 | */ |
| 1984 | if (my_grp->nr_tasks == grp->nr_tasks && my_grp > grp) |
Peter Zijlstra | 3354781 | 2013-10-09 10:24:48 +0200 | [diff] [blame] | 1985 | goto no_join; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1986 | |
Rik van Riel | dabe1d9 | 2013-10-07 11:29:34 +0100 | [diff] [blame] | 1987 | /* Always join threads in the same process. */ |
| 1988 | if (tsk->mm == current->mm) |
| 1989 | join = true; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 1990 | |
Rik van Riel | dabe1d9 | 2013-10-07 11:29:34 +0100 | [diff] [blame] | 1991 | /* Simple filter to avoid false positives due to PID collisions */ |
| 1992 | if (flags & TNF_SHARED) |
| 1993 | join = true; |
| 1994 | |
Mel Gorman | 3e6a941 | 2013-10-07 11:29:35 +0100 | [diff] [blame] | 1995 | /* Update priv based on whether false sharing was detected */ |
| 1996 | *priv = !join; |
| 1997 | |
Rik van Riel | dabe1d9 | 2013-10-07 11:29:34 +0100 | [diff] [blame] | 1998 | if (join && !get_numa_group(grp)) |
Peter Zijlstra | 3354781 | 2013-10-09 10:24:48 +0200 | [diff] [blame] | 1999 | goto no_join; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 2000 | |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 2001 | rcu_read_unlock(); |
| 2002 | |
| 2003 | if (!join) |
| 2004 | return; |
| 2005 | |
Mike Galbraith | 60e69ee | 2014-04-07 10:55:15 +0200 | [diff] [blame] | 2006 | BUG_ON(irqs_disabled()); |
| 2007 | double_lock_irq(&my_grp->lock, &grp->lock); |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 2008 | |
Rik van Riel | be1e4e7 | 2014-01-27 17:03:48 -0500 | [diff] [blame] | 2009 | for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) { |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 2010 | my_grp->faults[i] -= p->numa_faults[i]; |
| 2011 | grp->faults[i] += p->numa_faults[i]; |
Mel Gorman | 989348b | 2013-10-07 11:29:40 +0100 | [diff] [blame] | 2012 | } |
| 2013 | my_grp->total_faults -= p->total_numa_faults; |
| 2014 | grp->total_faults += p->total_numa_faults; |
| 2015 | |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 2016 | my_grp->nr_tasks--; |
| 2017 | grp->nr_tasks++; |
| 2018 | |
| 2019 | spin_unlock(&my_grp->lock); |
Mike Galbraith | 60e69ee | 2014-04-07 10:55:15 +0200 | [diff] [blame] | 2020 | spin_unlock_irq(&grp->lock); |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 2021 | |
| 2022 | rcu_assign_pointer(p->numa_group, grp); |
| 2023 | |
| 2024 | put_numa_group(my_grp); |
Peter Zijlstra | 3354781 | 2013-10-09 10:24:48 +0200 | [diff] [blame] | 2025 | return; |
| 2026 | |
| 2027 | no_join: |
| 2028 | rcu_read_unlock(); |
| 2029 | return; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 2030 | } |
| 2031 | |
| 2032 | void task_numa_free(struct task_struct *p) |
| 2033 | { |
| 2034 | struct numa_group *grp = p->numa_group; |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 2035 | void *numa_faults = p->numa_faults; |
Steven Rostedt | e9dd685 | 2014-05-27 17:02:04 -0400 | [diff] [blame] | 2036 | unsigned long flags; |
| 2037 | int i; |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 2038 | |
| 2039 | if (grp) { |
Steven Rostedt | e9dd685 | 2014-05-27 17:02:04 -0400 | [diff] [blame] | 2040 | spin_lock_irqsave(&grp->lock, flags); |
Rik van Riel | be1e4e7 | 2014-01-27 17:03:48 -0500 | [diff] [blame] | 2041 | for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 2042 | grp->faults[i] -= p->numa_faults[i]; |
Mel Gorman | 989348b | 2013-10-07 11:29:40 +0100 | [diff] [blame] | 2043 | grp->total_faults -= p->total_numa_faults; |
| 2044 | |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 2045 | grp->nr_tasks--; |
Steven Rostedt | e9dd685 | 2014-05-27 17:02:04 -0400 | [diff] [blame] | 2046 | spin_unlock_irqrestore(&grp->lock, flags); |
Andreea-Cristina Bernat | 35b123e | 2014-08-22 17:50:43 +0300 | [diff] [blame] | 2047 | RCU_INIT_POINTER(p->numa_group, NULL); |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 2048 | put_numa_group(grp); |
| 2049 | } |
| 2050 | |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 2051 | p->numa_faults = NULL; |
Rik van Riel | 8272701 | 2013-10-07 11:29:28 +0100 | [diff] [blame] | 2052 | kfree(numa_faults); |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 2053 | } |
| 2054 | |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2055 | /* |
| 2056 | * Got a PROT_NONE fault for a page on @node. |
| 2057 | */ |
Rik van Riel | 58b46da | 2014-01-27 17:03:47 -0500 | [diff] [blame] | 2058 | void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags) |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2059 | { |
| 2060 | struct task_struct *p = current; |
Peter Zijlstra | 6688cc0 | 2013-10-07 11:29:24 +0100 | [diff] [blame] | 2061 | bool migrated = flags & TNF_MIGRATED; |
Rik van Riel | 58b46da | 2014-01-27 17:03:47 -0500 | [diff] [blame] | 2062 | int cpu_node = task_node(current); |
Rik van Riel | 792568e | 2014-04-11 13:00:27 -0400 | [diff] [blame] | 2063 | int local = !!(flags & TNF_FAULT_LOCAL); |
Mel Gorman | ac8e895 | 2013-10-07 11:29:03 +0100 | [diff] [blame] | 2064 | int priv; |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2065 | |
Dave Kleikamp | 10e84b9 | 2013-07-31 13:53:35 -0700 | [diff] [blame] | 2066 | if (!numabalancing_enabled) |
Mel Gorman | 1a687c2 | 2012-11-22 11:16:36 +0000 | [diff] [blame] | 2067 | return; |
| 2068 | |
Mel Gorman | 9ff1d9f | 2013-10-07 11:29:04 +0100 | [diff] [blame] | 2069 | /* for example, ksmd faulting in a user's mm */ |
| 2070 | if (!p->mm) |
| 2071 | return; |
| 2072 | |
Mel Gorman | f809ca9 | 2013-10-07 11:28:57 +0100 | [diff] [blame] | 2073 | /* Allocate buffer to track faults on a per-node basis */ |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 2074 | if (unlikely(!p->numa_faults)) { |
| 2075 | int size = sizeof(*p->numa_faults) * |
Rik van Riel | be1e4e7 | 2014-01-27 17:03:48 -0500 | [diff] [blame] | 2076 | NR_NUMA_HINT_FAULT_BUCKETS * nr_node_ids; |
Mel Gorman | f809ca9 | 2013-10-07 11:28:57 +0100 | [diff] [blame] | 2077 | |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 2078 | p->numa_faults = kzalloc(size, GFP_KERNEL|__GFP_NOWARN); |
| 2079 | if (!p->numa_faults) |
Mel Gorman | f809ca9 | 2013-10-07 11:28:57 +0100 | [diff] [blame] | 2080 | return; |
Mel Gorman | 745d614 | 2013-10-07 11:28:59 +0100 | [diff] [blame] | 2081 | |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 2082 | p->total_numa_faults = 0; |
Rik van Riel | 04bb2f9 | 2013-10-07 11:29:36 +0100 | [diff] [blame] | 2083 | memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality)); |
Mel Gorman | f809ca9 | 2013-10-07 11:28:57 +0100 | [diff] [blame] | 2084 | } |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2085 | |
Mel Gorman | fb003b8 | 2012-11-15 09:01:14 +0000 | [diff] [blame] | 2086 | /* |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 2087 | * First accesses are treated as private, otherwise consider accesses |
| 2088 | * to be private if the accessing pid has not changed |
| 2089 | */ |
| 2090 | if (unlikely(last_cpupid == (-1 & LAST_CPUPID_MASK))) { |
| 2091 | priv = 1; |
| 2092 | } else { |
| 2093 | priv = cpupid_match_pid(p, last_cpupid); |
Peter Zijlstra | 6688cc0 | 2013-10-07 11:29:24 +0100 | [diff] [blame] | 2094 | if (!priv && !(flags & TNF_NO_GROUP)) |
Mel Gorman | 3e6a941 | 2013-10-07 11:29:35 +0100 | [diff] [blame] | 2095 | task_numa_group(p, last_cpupid, flags, &priv); |
Peter Zijlstra | 8c8a743 | 2013-10-07 11:29:21 +0100 | [diff] [blame] | 2096 | } |
| 2097 | |
Rik van Riel | 792568e | 2014-04-11 13:00:27 -0400 | [diff] [blame] | 2098 | /* |
| 2099 | * If a workload spans multiple NUMA nodes, a shared fault that |
| 2100 | * occurs wholly within the set of nodes that the workload is |
| 2101 | * actively using should be counted as local. This allows the |
| 2102 | * scan rate to slow down when a workload has settled down. |
| 2103 | */ |
| 2104 | if (!priv && !local && p->numa_group && |
| 2105 | node_isset(cpu_node, p->numa_group->active_nodes) && |
| 2106 | node_isset(mem_node, p->numa_group->active_nodes)) |
| 2107 | local = 1; |
| 2108 | |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2109 | task_numa_placement(p); |
Mel Gorman | f809ca9 | 2013-10-07 11:28:57 +0100 | [diff] [blame] | 2110 | |
Rik van Riel | 2739d3e | 2013-10-07 11:29:41 +0100 | [diff] [blame] | 2111 | /* |
| 2112 | * Retry task to preferred node migration periodically, in case it |
| 2113 | * case it previously failed, or the scheduler moved us. |
| 2114 | */ |
| 2115 | if (time_after(jiffies, p->numa_migrate_retry)) |
Mel Gorman | 6b9a746 | 2013-10-07 11:29:11 +0100 | [diff] [blame] | 2116 | numa_migrate_preferred(p); |
| 2117 | |
Ingo Molnar | b32e86b | 2013-10-07 11:29:30 +0100 | [diff] [blame] | 2118 | if (migrated) |
| 2119 | p->numa_pages_migrated += pages; |
Mel Gorman | 074c238 | 2015-03-25 15:55:42 -0700 | [diff] [blame] | 2120 | if (flags & TNF_MIGRATE_FAIL) |
| 2121 | p->numa_faults_locality[2] += pages; |
Ingo Molnar | b32e86b | 2013-10-07 11:29:30 +0100 | [diff] [blame] | 2122 | |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 2123 | p->numa_faults[task_faults_idx(NUMA_MEMBUF, mem_node, priv)] += pages; |
| 2124 | p->numa_faults[task_faults_idx(NUMA_CPUBUF, cpu_node, priv)] += pages; |
Rik van Riel | 792568e | 2014-04-11 13:00:27 -0400 | [diff] [blame] | 2125 | p->numa_faults_locality[local] += pages; |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2126 | } |
| 2127 | |
Peter Zijlstra | 6e5fb22 | 2012-10-25 14:16:45 +0200 | [diff] [blame] | 2128 | static void reset_ptenuma_scan(struct task_struct *p) |
| 2129 | { |
Jason Low | 7e5a2c1 | 2015-04-30 17:28:14 -0700 | [diff] [blame] | 2130 | /* |
| 2131 | * We only did a read acquisition of the mmap sem, so |
| 2132 | * p->mm->numa_scan_seq is written to without exclusive access |
| 2133 | * and the update is not guaranteed to be atomic. That's not |
| 2134 | * much of an issue though, since this is just used for |
| 2135 | * statistical sampling. Use READ_ONCE/WRITE_ONCE, which are not |
| 2136 | * expensive, to avoid any form of compiler optimizations: |
| 2137 | */ |
Jason Low | 316c1608d | 2015-04-28 13:00:20 -0700 | [diff] [blame] | 2138 | WRITE_ONCE(p->mm->numa_scan_seq, READ_ONCE(p->mm->numa_scan_seq) + 1); |
Peter Zijlstra | 6e5fb22 | 2012-10-25 14:16:45 +0200 | [diff] [blame] | 2139 | p->mm->numa_scan_offset = 0; |
| 2140 | } |
| 2141 | |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2142 | /* |
| 2143 | * The expensive part of numa migration is done from task_work context. |
| 2144 | * Triggered from task_tick_numa(). |
| 2145 | */ |
| 2146 | void task_numa_work(struct callback_head *work) |
| 2147 | { |
| 2148 | unsigned long migrate, next_scan, now = jiffies; |
| 2149 | struct task_struct *p = current; |
| 2150 | struct mm_struct *mm = p->mm; |
Peter Zijlstra | 6e5fb22 | 2012-10-25 14:16:45 +0200 | [diff] [blame] | 2151 | struct vm_area_struct *vma; |
Mel Gorman | 9f40604 | 2012-11-14 18:34:32 +0000 | [diff] [blame] | 2152 | unsigned long start, end; |
Mel Gorman | 598f0ec | 2013-10-07 11:28:55 +0100 | [diff] [blame] | 2153 | unsigned long nr_pte_updates = 0; |
Mel Gorman | 9f40604 | 2012-11-14 18:34:32 +0000 | [diff] [blame] | 2154 | long pages; |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2155 | |
| 2156 | WARN_ON_ONCE(p != container_of(work, struct task_struct, numa_work)); |
| 2157 | |
| 2158 | work->next = work; /* protect against double add */ |
| 2159 | /* |
| 2160 | * Who cares about NUMA placement when they're dying. |
| 2161 | * |
| 2162 | * NOTE: make sure not to dereference p->mm before this check, |
| 2163 | * exit_task_work() happens _after_ exit_mm() so we could be called |
| 2164 | * without p->mm even though we still had it when we enqueued this |
| 2165 | * work. |
| 2166 | */ |
| 2167 | if (p->flags & PF_EXITING) |
| 2168 | return; |
| 2169 | |
Mel Gorman | 930aa17 | 2013-10-07 11:29:37 +0100 | [diff] [blame] | 2170 | if (!mm->numa_next_scan) { |
Mel Gorman | 7e8d16b | 2013-10-07 11:28:54 +0100 | [diff] [blame] | 2171 | mm->numa_next_scan = now + |
| 2172 | msecs_to_jiffies(sysctl_numa_balancing_scan_delay); |
Mel Gorman | b8593bf | 2012-11-21 01:18:23 +0000 | [diff] [blame] | 2173 | } |
| 2174 | |
| 2175 | /* |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2176 | * Enforce maximal scan/migration frequency.. |
| 2177 | */ |
| 2178 | migrate = mm->numa_next_scan; |
| 2179 | if (time_before(now, migrate)) |
| 2180 | return; |
| 2181 | |
Mel Gorman | 598f0ec | 2013-10-07 11:28:55 +0100 | [diff] [blame] | 2182 | if (p->numa_scan_period == 0) { |
| 2183 | p->numa_scan_period_max = task_scan_max(p); |
| 2184 | p->numa_scan_period = task_scan_min(p); |
| 2185 | } |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2186 | |
Mel Gorman | fb003b8 | 2012-11-15 09:01:14 +0000 | [diff] [blame] | 2187 | next_scan = now + msecs_to_jiffies(p->numa_scan_period); |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2188 | if (cmpxchg(&mm->numa_next_scan, migrate, next_scan) != migrate) |
| 2189 | return; |
| 2190 | |
Mel Gorman | e14808b | 2012-11-19 10:59:15 +0000 | [diff] [blame] | 2191 | /* |
Peter Zijlstra | 19a78d1 | 2013-10-07 11:28:51 +0100 | [diff] [blame] | 2192 | * Delay this task enough that another task of this mm will likely win |
| 2193 | * the next time around. |
| 2194 | */ |
| 2195 | p->node_stamp += 2 * TICK_NSEC; |
| 2196 | |
Mel Gorman | 9f40604 | 2012-11-14 18:34:32 +0000 | [diff] [blame] | 2197 | start = mm->numa_scan_offset; |
| 2198 | pages = sysctl_numa_balancing_scan_size; |
| 2199 | pages <<= 20 - PAGE_SHIFT; /* MB in pages */ |
| 2200 | if (!pages) |
| 2201 | return; |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2202 | |
Peter Zijlstra | 6e5fb22 | 2012-10-25 14:16:45 +0200 | [diff] [blame] | 2203 | down_read(&mm->mmap_sem); |
Mel Gorman | 9f40604 | 2012-11-14 18:34:32 +0000 | [diff] [blame] | 2204 | vma = find_vma(mm, start); |
Peter Zijlstra | 6e5fb22 | 2012-10-25 14:16:45 +0200 | [diff] [blame] | 2205 | if (!vma) { |
| 2206 | reset_ptenuma_scan(p); |
Mel Gorman | 9f40604 | 2012-11-14 18:34:32 +0000 | [diff] [blame] | 2207 | start = 0; |
Peter Zijlstra | 6e5fb22 | 2012-10-25 14:16:45 +0200 | [diff] [blame] | 2208 | vma = mm->mmap; |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2209 | } |
Mel Gorman | 9f40604 | 2012-11-14 18:34:32 +0000 | [diff] [blame] | 2210 | for (; vma; vma = vma->vm_next) { |
Naoya Horiguchi | 6b79c57 | 2015-04-07 14:26:47 -0700 | [diff] [blame] | 2211 | if (!vma_migratable(vma) || !vma_policy_mof(vma) || |
Mel Gorman | 8e76d4e | 2015-06-10 11:15:00 -0700 | [diff] [blame] | 2212 | is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_MIXEDMAP)) { |
Peter Zijlstra | 6e5fb22 | 2012-10-25 14:16:45 +0200 | [diff] [blame] | 2213 | continue; |
Naoya Horiguchi | 6b79c57 | 2015-04-07 14:26:47 -0700 | [diff] [blame] | 2214 | } |
Peter Zijlstra | 6e5fb22 | 2012-10-25 14:16:45 +0200 | [diff] [blame] | 2215 | |
Mel Gorman | 4591ce4f | 2013-10-07 11:29:13 +0100 | [diff] [blame] | 2216 | /* |
| 2217 | * Shared library pages mapped by multiple processes are not |
| 2218 | * migrated as it is expected they are cache replicated. Avoid |
| 2219 | * hinting faults in read-only file-backed mappings or the vdso |
| 2220 | * as migrating the pages will be of marginal benefit. |
| 2221 | */ |
| 2222 | if (!vma->vm_mm || |
| 2223 | (vma->vm_file && (vma->vm_flags & (VM_READ|VM_WRITE)) == (VM_READ))) |
| 2224 | continue; |
| 2225 | |
Mel Gorman | 3c67f47 | 2013-12-18 17:08:40 -0800 | [diff] [blame] | 2226 | /* |
| 2227 | * Skip inaccessible VMAs to avoid any confusion between |
| 2228 | * PROT_NONE and NUMA hinting ptes |
| 2229 | */ |
| 2230 | if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) |
| 2231 | continue; |
| 2232 | |
Mel Gorman | 9f40604 | 2012-11-14 18:34:32 +0000 | [diff] [blame] | 2233 | do { |
| 2234 | start = max(start, vma->vm_start); |
| 2235 | end = ALIGN(start + (pages << PAGE_SHIFT), HPAGE_SIZE); |
| 2236 | end = min(end, vma->vm_end); |
Mel Gorman | 598f0ec | 2013-10-07 11:28:55 +0100 | [diff] [blame] | 2237 | nr_pte_updates += change_prot_numa(vma, start, end); |
| 2238 | |
| 2239 | /* |
| 2240 | * Scan sysctl_numa_balancing_scan_size but ensure that |
| 2241 | * at least one PTE is updated so that unused virtual |
| 2242 | * address space is quickly skipped. |
| 2243 | */ |
| 2244 | if (nr_pte_updates) |
| 2245 | pages -= (end - start) >> PAGE_SHIFT; |
Peter Zijlstra | 6e5fb22 | 2012-10-25 14:16:45 +0200 | [diff] [blame] | 2246 | |
Mel Gorman | 9f40604 | 2012-11-14 18:34:32 +0000 | [diff] [blame] | 2247 | start = end; |
| 2248 | if (pages <= 0) |
| 2249 | goto out; |
Rik van Riel | 3cf1962 | 2014-02-18 17:12:44 -0500 | [diff] [blame] | 2250 | |
| 2251 | cond_resched(); |
Mel Gorman | 9f40604 | 2012-11-14 18:34:32 +0000 | [diff] [blame] | 2252 | } while (end != vma->vm_end); |
Peter Zijlstra | 6e5fb22 | 2012-10-25 14:16:45 +0200 | [diff] [blame] | 2253 | } |
| 2254 | |
Mel Gorman | 9f40604 | 2012-11-14 18:34:32 +0000 | [diff] [blame] | 2255 | out: |
Peter Zijlstra | 6e5fb22 | 2012-10-25 14:16:45 +0200 | [diff] [blame] | 2256 | /* |
Peter Zijlstra | c69307d | 2013-10-07 11:28:41 +0100 | [diff] [blame] | 2257 | * It is possible to reach the end of the VMA list but the last few |
| 2258 | * VMAs are not guaranteed to the vma_migratable. If they are not, we |
| 2259 | * would find the !migratable VMA on the next scan but not reset the |
| 2260 | * scanner to the start so check it now. |
Peter Zijlstra | 6e5fb22 | 2012-10-25 14:16:45 +0200 | [diff] [blame] | 2261 | */ |
| 2262 | if (vma) |
Mel Gorman | 9f40604 | 2012-11-14 18:34:32 +0000 | [diff] [blame] | 2263 | mm->numa_scan_offset = start; |
Peter Zijlstra | 6e5fb22 | 2012-10-25 14:16:45 +0200 | [diff] [blame] | 2264 | else |
| 2265 | reset_ptenuma_scan(p); |
| 2266 | up_read(&mm->mmap_sem); |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2267 | } |
| 2268 | |
| 2269 | /* |
| 2270 | * Drive the periodic memory faults.. |
| 2271 | */ |
| 2272 | void task_tick_numa(struct rq *rq, struct task_struct *curr) |
| 2273 | { |
| 2274 | struct callback_head *work = &curr->numa_work; |
| 2275 | u64 period, now; |
| 2276 | |
| 2277 | /* |
| 2278 | * We don't care about NUMA placement if we don't have memory. |
| 2279 | */ |
| 2280 | if (!curr->mm || (curr->flags & PF_EXITING) || work->next != work) |
| 2281 | return; |
| 2282 | |
| 2283 | /* |
| 2284 | * Using runtime rather than walltime has the dual advantage that |
| 2285 | * we (mostly) drive the selection from busy threads and that the |
| 2286 | * task needs to have done some actual work before we bother with |
| 2287 | * NUMA placement. |
| 2288 | */ |
| 2289 | now = curr->se.sum_exec_runtime; |
| 2290 | period = (u64)curr->numa_scan_period * NSEC_PER_MSEC; |
| 2291 | |
| 2292 | if (now - curr->node_stamp > period) { |
Peter Zijlstra | 4b96a29 | 2012-10-25 14:16:47 +0200 | [diff] [blame] | 2293 | if (!curr->node_stamp) |
Mel Gorman | 598f0ec | 2013-10-07 11:28:55 +0100 | [diff] [blame] | 2294 | curr->numa_scan_period = task_scan_min(curr); |
Peter Zijlstra | 19a78d1 | 2013-10-07 11:28:51 +0100 | [diff] [blame] | 2295 | curr->node_stamp += period; |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2296 | |
| 2297 | if (!time_before(jiffies, curr->mm->numa_next_scan)) { |
| 2298 | init_task_work(work, task_numa_work); /* TODO: move this into sched_fork() */ |
| 2299 | task_work_add(curr, work, true); |
| 2300 | } |
| 2301 | } |
| 2302 | } |
| 2303 | #else |
| 2304 | static void task_tick_numa(struct rq *rq, struct task_struct *curr) |
| 2305 | { |
| 2306 | } |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 2307 | |
| 2308 | static inline void account_numa_enqueue(struct rq *rq, struct task_struct *p) |
| 2309 | { |
| 2310 | } |
| 2311 | |
| 2312 | static inline void account_numa_dequeue(struct rq *rq, struct task_struct *p) |
| 2313 | { |
| 2314 | } |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 2315 | #endif /* CONFIG_NUMA_BALANCING */ |
| 2316 | |
Dmitry Adamushko | 30cfdcf | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 2317 | static void |
| 2318 | account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
| 2319 | { |
| 2320 | update_load_add(&cfs_rq->load, se->load.weight); |
Peter Zijlstra | c09595f | 2008-06-27 13:41:14 +0200 | [diff] [blame] | 2321 | if (!parent_entity(se)) |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 2322 | update_load_add(&rq_of(cfs_rq)->load, se->load.weight); |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 2323 | #ifdef CONFIG_SMP |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 2324 | if (entity_is_task(se)) { |
| 2325 | struct rq *rq = rq_of(cfs_rq); |
| 2326 | |
| 2327 | account_numa_enqueue(rq, task_of(se)); |
| 2328 | list_add(&se->group_node, &rq->cfs_tasks); |
| 2329 | } |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 2330 | #endif |
Dmitry Adamushko | 30cfdcf | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 2331 | cfs_rq->nr_running++; |
Dmitry Adamushko | 30cfdcf | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 2332 | } |
| 2333 | |
| 2334 | static void |
| 2335 | account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) |
| 2336 | { |
| 2337 | update_load_sub(&cfs_rq->load, se->load.weight); |
Peter Zijlstra | c09595f | 2008-06-27 13:41:14 +0200 | [diff] [blame] | 2338 | if (!parent_entity(se)) |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 2339 | update_load_sub(&rq_of(cfs_rq)->load, se->load.weight); |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 2340 | if (entity_is_task(se)) { |
| 2341 | account_numa_dequeue(rq_of(cfs_rq), task_of(se)); |
Bharata B Rao | b87f172 | 2008-09-25 09:53:54 +0530 | [diff] [blame] | 2342 | list_del_init(&se->group_node); |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 2343 | } |
Dmitry Adamushko | 30cfdcf | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 2344 | cfs_rq->nr_running--; |
Dmitry Adamushko | 30cfdcf | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 2345 | } |
| 2346 | |
Yong Zhang | 3ff6dca | 2011-01-24 15:33:52 +0800 | [diff] [blame] | 2347 | #ifdef CONFIG_FAIR_GROUP_SCHED |
| 2348 | # ifdef CONFIG_SMP |
Peter Zijlstra | cf5f0ac | 2011-10-13 16:52:28 +0200 | [diff] [blame] | 2349 | static inline long calc_tg_weight(struct task_group *tg, struct cfs_rq *cfs_rq) |
| 2350 | { |
| 2351 | long tg_weight; |
| 2352 | |
| 2353 | /* |
| 2354 | * Use this CPU's actual weight instead of the last load_contribution |
| 2355 | * to gain a more accurate current total weight. See |
| 2356 | * update_cfs_rq_load_contribution(). |
| 2357 | */ |
Alex Shi | bf5b986 | 2013-06-20 10:18:54 +0800 | [diff] [blame] | 2358 | tg_weight = atomic_long_read(&tg->load_avg); |
Paul Turner | 8295836 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2359 | tg_weight -= cfs_rq->tg_load_contrib; |
Peter Zijlstra | cf5f0ac | 2011-10-13 16:52:28 +0200 | [diff] [blame] | 2360 | tg_weight += cfs_rq->load.weight; |
| 2361 | |
| 2362 | return tg_weight; |
| 2363 | } |
| 2364 | |
Paul Turner | 6d5ab29 | 2011-01-21 20:45:01 -0800 | [diff] [blame] | 2365 | static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg) |
Yong Zhang | 3ff6dca | 2011-01-24 15:33:52 +0800 | [diff] [blame] | 2366 | { |
Peter Zijlstra | cf5f0ac | 2011-10-13 16:52:28 +0200 | [diff] [blame] | 2367 | long tg_weight, load, shares; |
Yong Zhang | 3ff6dca | 2011-01-24 15:33:52 +0800 | [diff] [blame] | 2368 | |
Peter Zijlstra | cf5f0ac | 2011-10-13 16:52:28 +0200 | [diff] [blame] | 2369 | tg_weight = calc_tg_weight(tg, cfs_rq); |
Paul Turner | 6d5ab29 | 2011-01-21 20:45:01 -0800 | [diff] [blame] | 2370 | load = cfs_rq->load.weight; |
Yong Zhang | 3ff6dca | 2011-01-24 15:33:52 +0800 | [diff] [blame] | 2371 | |
Yong Zhang | 3ff6dca | 2011-01-24 15:33:52 +0800 | [diff] [blame] | 2372 | shares = (tg->shares * load); |
Peter Zijlstra | cf5f0ac | 2011-10-13 16:52:28 +0200 | [diff] [blame] | 2373 | if (tg_weight) |
| 2374 | shares /= tg_weight; |
Yong Zhang | 3ff6dca | 2011-01-24 15:33:52 +0800 | [diff] [blame] | 2375 | |
| 2376 | if (shares < MIN_SHARES) |
| 2377 | shares = MIN_SHARES; |
| 2378 | if (shares > tg->shares) |
| 2379 | shares = tg->shares; |
| 2380 | |
| 2381 | return shares; |
| 2382 | } |
Yong Zhang | 3ff6dca | 2011-01-24 15:33:52 +0800 | [diff] [blame] | 2383 | # else /* CONFIG_SMP */ |
Paul Turner | 6d5ab29 | 2011-01-21 20:45:01 -0800 | [diff] [blame] | 2384 | static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg) |
Yong Zhang | 3ff6dca | 2011-01-24 15:33:52 +0800 | [diff] [blame] | 2385 | { |
| 2386 | return tg->shares; |
| 2387 | } |
Yong Zhang | 3ff6dca | 2011-01-24 15:33:52 +0800 | [diff] [blame] | 2388 | # endif /* CONFIG_SMP */ |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 2389 | static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, |
| 2390 | unsigned long weight) |
| 2391 | { |
Paul Turner | 19e5eeb | 2010-12-15 19:10:18 -0800 | [diff] [blame] | 2392 | if (se->on_rq) { |
| 2393 | /* commit outstanding execution time */ |
| 2394 | if (cfs_rq->curr == se) |
| 2395 | update_curr(cfs_rq); |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 2396 | account_entity_dequeue(cfs_rq, se); |
Paul Turner | 19e5eeb | 2010-12-15 19:10:18 -0800 | [diff] [blame] | 2397 | } |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 2398 | |
| 2399 | update_load_set(&se->load, weight); |
| 2400 | |
| 2401 | if (se->on_rq) |
| 2402 | account_entity_enqueue(cfs_rq, se); |
| 2403 | } |
| 2404 | |
Paul Turner | 8295836 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2405 | static inline int throttled_hierarchy(struct cfs_rq *cfs_rq); |
| 2406 | |
Paul Turner | 6d5ab29 | 2011-01-21 20:45:01 -0800 | [diff] [blame] | 2407 | static void update_cfs_shares(struct cfs_rq *cfs_rq) |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 2408 | { |
| 2409 | struct task_group *tg; |
| 2410 | struct sched_entity *se; |
Yong Zhang | 3ff6dca | 2011-01-24 15:33:52 +0800 | [diff] [blame] | 2411 | long shares; |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 2412 | |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 2413 | tg = cfs_rq->tg; |
| 2414 | se = tg->se[cpu_of(rq_of(cfs_rq))]; |
Paul Turner | 64660c8 | 2011-07-21 09:43:36 -0700 | [diff] [blame] | 2415 | if (!se || throttled_hierarchy(cfs_rq)) |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 2416 | return; |
Yong Zhang | 3ff6dca | 2011-01-24 15:33:52 +0800 | [diff] [blame] | 2417 | #ifndef CONFIG_SMP |
| 2418 | if (likely(se->load.weight == tg->shares)) |
| 2419 | return; |
| 2420 | #endif |
Paul Turner | 6d5ab29 | 2011-01-21 20:45:01 -0800 | [diff] [blame] | 2421 | shares = calc_cfs_shares(cfs_rq, tg); |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 2422 | |
| 2423 | reweight_entity(cfs_rq_of(se), se, shares); |
| 2424 | } |
| 2425 | #else /* CONFIG_FAIR_GROUP_SCHED */ |
Paul Turner | 6d5ab29 | 2011-01-21 20:45:01 -0800 | [diff] [blame] | 2426 | static inline void update_cfs_shares(struct cfs_rq *cfs_rq) |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 2427 | { |
| 2428 | } |
| 2429 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
| 2430 | |
Alex Shi | 141965c | 2013-06-26 13:05:39 +0800 | [diff] [blame] | 2431 | #ifdef CONFIG_SMP |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2432 | /* |
Paul Turner | 5b51f2f | 2012-10-04 13:18:32 +0200 | [diff] [blame] | 2433 | * We choose a half-life close to 1 scheduling period. |
| 2434 | * Note: The tables below are dependent on this value. |
| 2435 | */ |
| 2436 | #define LOAD_AVG_PERIOD 32 |
| 2437 | #define LOAD_AVG_MAX 47742 /* maximum possible load avg */ |
| 2438 | #define LOAD_AVG_MAX_N 345 /* number of full periods to produce LOAD_MAX_AVG */ |
| 2439 | |
| 2440 | /* Precomputed fixed inverse multiplies for multiplication by y^n */ |
| 2441 | static const u32 runnable_avg_yN_inv[] = { |
| 2442 | 0xffffffff, 0xfa83b2da, 0xf5257d14, 0xefe4b99a, 0xeac0c6e6, 0xe5b906e6, |
| 2443 | 0xe0ccdeeb, 0xdbfbb796, 0xd744fcc9, 0xd2a81d91, 0xce248c14, 0xc9b9bd85, |
| 2444 | 0xc5672a10, 0xc12c4cc9, 0xbd08a39e, 0xb8fbaf46, 0xb504f333, 0xb123f581, |
| 2445 | 0xad583ee9, 0xa9a15ab4, 0xa5fed6a9, 0xa2704302, 0x9ef5325f, 0x9b8d39b9, |
| 2446 | 0x9837f050, 0x94f4efa8, 0x91c3d373, 0x8ea4398a, 0x8b95c1e3, 0x88980e80, |
| 2447 | 0x85aac367, 0x82cd8698, |
| 2448 | }; |
| 2449 | |
| 2450 | /* |
| 2451 | * Precomputed \Sum y^k { 1<=k<=n }. These are floor(true_value) to prevent |
| 2452 | * over-estimates when re-combining. |
| 2453 | */ |
| 2454 | static const u32 runnable_avg_yN_sum[] = { |
| 2455 | 0, 1002, 1982, 2941, 3880, 4798, 5697, 6576, 7437, 8279, 9103, |
| 2456 | 9909,10698,11470,12226,12966,13690,14398,15091,15769,16433,17082, |
| 2457 | 17718,18340,18949,19545,20128,20698,21256,21802,22336,22859,23371, |
| 2458 | }; |
| 2459 | |
| 2460 | /* |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2461 | * Approximate: |
| 2462 | * val * y^n, where y^32 ~= 0.5 (~1 scheduling period) |
| 2463 | */ |
| 2464 | static __always_inline u64 decay_load(u64 val, u64 n) |
| 2465 | { |
Paul Turner | 5b51f2f | 2012-10-04 13:18:32 +0200 | [diff] [blame] | 2466 | unsigned int local_n; |
| 2467 | |
| 2468 | if (!n) |
| 2469 | return val; |
| 2470 | else if (unlikely(n > LOAD_AVG_PERIOD * 63)) |
| 2471 | return 0; |
| 2472 | |
| 2473 | /* after bounds checking we can collapse to 32-bit */ |
| 2474 | local_n = n; |
| 2475 | |
| 2476 | /* |
| 2477 | * As y^PERIOD = 1/2, we can combine |
Zhihui Zhang | 9c58c79 | 2014-09-20 21:24:36 -0400 | [diff] [blame] | 2478 | * y^n = 1/2^(n/PERIOD) * y^(n%PERIOD) |
| 2479 | * With a look-up table which covers y^n (n<PERIOD) |
Paul Turner | 5b51f2f | 2012-10-04 13:18:32 +0200 | [diff] [blame] | 2480 | * |
| 2481 | * To achieve constant time decay_load. |
| 2482 | */ |
| 2483 | if (unlikely(local_n >= LOAD_AVG_PERIOD)) { |
| 2484 | val >>= local_n / LOAD_AVG_PERIOD; |
| 2485 | local_n %= LOAD_AVG_PERIOD; |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2486 | } |
| 2487 | |
Paul Turner | 5b51f2f | 2012-10-04 13:18:32 +0200 | [diff] [blame] | 2488 | val *= runnable_avg_yN_inv[local_n]; |
| 2489 | /* We don't use SRR here since we always want to round down. */ |
| 2490 | return val >> 32; |
| 2491 | } |
| 2492 | |
| 2493 | /* |
| 2494 | * For updates fully spanning n periods, the contribution to runnable |
| 2495 | * average will be: \Sum 1024*y^n |
| 2496 | * |
| 2497 | * We can compute this reasonably efficiently by combining: |
| 2498 | * y^PERIOD = 1/2 with precomputed \Sum 1024*y^n {for n <PERIOD} |
| 2499 | */ |
| 2500 | static u32 __compute_runnable_contrib(u64 n) |
| 2501 | { |
| 2502 | u32 contrib = 0; |
| 2503 | |
| 2504 | if (likely(n <= LOAD_AVG_PERIOD)) |
| 2505 | return runnable_avg_yN_sum[n]; |
| 2506 | else if (unlikely(n >= LOAD_AVG_MAX_N)) |
| 2507 | return LOAD_AVG_MAX; |
| 2508 | |
| 2509 | /* Compute \Sum k^n combining precomputed values for k^i, \Sum k^j */ |
| 2510 | do { |
| 2511 | contrib /= 2; /* y^LOAD_AVG_PERIOD = 1/2 */ |
| 2512 | contrib += runnable_avg_yN_sum[LOAD_AVG_PERIOD]; |
| 2513 | |
| 2514 | n -= LOAD_AVG_PERIOD; |
| 2515 | } while (n > LOAD_AVG_PERIOD); |
| 2516 | |
| 2517 | contrib = decay_load(contrib, n); |
| 2518 | return contrib + runnable_avg_yN_sum[n]; |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2519 | } |
| 2520 | |
| 2521 | /* |
| 2522 | * We can represent the historical contribution to runnable average as the |
| 2523 | * coefficients of a geometric series. To do this we sub-divide our runnable |
| 2524 | * history into segments of approximately 1ms (1024us); label the segment that |
| 2525 | * occurred N-ms ago p_N, with p_0 corresponding to the current period, e.g. |
| 2526 | * |
| 2527 | * [<- 1024us ->|<- 1024us ->|<- 1024us ->| ... |
| 2528 | * p0 p1 p2 |
| 2529 | * (now) (~1ms ago) (~2ms ago) |
| 2530 | * |
| 2531 | * Let u_i denote the fraction of p_i that the entity was runnable. |
| 2532 | * |
| 2533 | * We then designate the fractions u_i as our co-efficients, yielding the |
| 2534 | * following representation of historical load: |
| 2535 | * u_0 + u_1*y + u_2*y^2 + u_3*y^3 + ... |
| 2536 | * |
| 2537 | * We choose y based on the with of a reasonably scheduling period, fixing: |
| 2538 | * y^32 = 0.5 |
| 2539 | * |
| 2540 | * This means that the contribution to load ~32ms ago (u_32) will be weighted |
| 2541 | * approximately half as much as the contribution to load within the last ms |
| 2542 | * (u_0). |
| 2543 | * |
| 2544 | * When a period "rolls over" and we have new u_0`, multiplying the previous |
| 2545 | * sum again by y is sufficient to update: |
| 2546 | * load_avg = u_0` + y*(u_0 + u_1*y + u_2*y^2 + ... ) |
| 2547 | * = u_0 + u_1*y + u_2*y^2 + ... [re-labeling u_i --> u_{i+1}] |
| 2548 | */ |
Morten Rasmussen | 0c1dc6b | 2015-03-04 08:46:26 +0100 | [diff] [blame] | 2549 | static __always_inline int __update_entity_runnable_avg(u64 now, int cpu, |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2550 | struct sched_avg *sa, |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2551 | int runnable, |
| 2552 | int running) |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2553 | { |
Paul Turner | 5b51f2f | 2012-10-04 13:18:32 +0200 | [diff] [blame] | 2554 | u64 delta, periods; |
| 2555 | u32 runnable_contrib; |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2556 | int delta_w, decayed = 0; |
Morten Rasmussen | 0c1dc6b | 2015-03-04 08:46:26 +0100 | [diff] [blame] | 2557 | unsigned long scale_freq = arch_scale_freq_capacity(NULL, cpu); |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2558 | |
| 2559 | delta = now - sa->last_runnable_update; |
| 2560 | /* |
| 2561 | * This should only happen when time goes backwards, which it |
| 2562 | * unfortunately does during sched clock init when we swap over to TSC. |
| 2563 | */ |
| 2564 | if ((s64)delta < 0) { |
| 2565 | sa->last_runnable_update = now; |
| 2566 | return 0; |
| 2567 | } |
| 2568 | |
| 2569 | /* |
| 2570 | * Use 1024ns as the unit of measurement since it's a reasonable |
| 2571 | * approximation of 1us and fast to compute. |
| 2572 | */ |
| 2573 | delta >>= 10; |
| 2574 | if (!delta) |
| 2575 | return 0; |
| 2576 | sa->last_runnable_update = now; |
| 2577 | |
| 2578 | /* delta_w is the amount already accumulated against our next period */ |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2579 | delta_w = sa->avg_period % 1024; |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2580 | if (delta + delta_w >= 1024) { |
| 2581 | /* period roll-over */ |
| 2582 | decayed = 1; |
| 2583 | |
| 2584 | /* |
| 2585 | * Now that we know we're crossing a period boundary, figure |
| 2586 | * out how much from delta we need to complete the current |
| 2587 | * period and accrue it. |
| 2588 | */ |
| 2589 | delta_w = 1024 - delta_w; |
Paul Turner | 5b51f2f | 2012-10-04 13:18:32 +0200 | [diff] [blame] | 2590 | if (runnable) |
| 2591 | sa->runnable_avg_sum += delta_w; |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2592 | if (running) |
Morten Rasmussen | 0c1dc6b | 2015-03-04 08:46:26 +0100 | [diff] [blame] | 2593 | sa->running_avg_sum += delta_w * scale_freq |
| 2594 | >> SCHED_CAPACITY_SHIFT; |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2595 | sa->avg_period += delta_w; |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2596 | |
Paul Turner | 5b51f2f | 2012-10-04 13:18:32 +0200 | [diff] [blame] | 2597 | delta -= delta_w; |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2598 | |
Paul Turner | 5b51f2f | 2012-10-04 13:18:32 +0200 | [diff] [blame] | 2599 | /* Figure out how many additional periods this update spans */ |
| 2600 | periods = delta / 1024; |
| 2601 | delta %= 1024; |
| 2602 | |
| 2603 | sa->runnable_avg_sum = decay_load(sa->runnable_avg_sum, |
| 2604 | periods + 1); |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2605 | sa->running_avg_sum = decay_load(sa->running_avg_sum, |
| 2606 | periods + 1); |
| 2607 | sa->avg_period = decay_load(sa->avg_period, |
Paul Turner | 5b51f2f | 2012-10-04 13:18:32 +0200 | [diff] [blame] | 2608 | periods + 1); |
| 2609 | |
| 2610 | /* Efficiently calculate \sum (1..n_period) 1024*y^i */ |
| 2611 | runnable_contrib = __compute_runnable_contrib(periods); |
| 2612 | if (runnable) |
| 2613 | sa->runnable_avg_sum += runnable_contrib; |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2614 | if (running) |
Morten Rasmussen | 0c1dc6b | 2015-03-04 08:46:26 +0100 | [diff] [blame] | 2615 | sa->running_avg_sum += runnable_contrib * scale_freq |
| 2616 | >> SCHED_CAPACITY_SHIFT; |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2617 | sa->avg_period += runnable_contrib; |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2618 | } |
| 2619 | |
| 2620 | /* Remainder of delta accrued against u_0` */ |
| 2621 | if (runnable) |
| 2622 | sa->runnable_avg_sum += delta; |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2623 | if (running) |
Morten Rasmussen | 0c1dc6b | 2015-03-04 08:46:26 +0100 | [diff] [blame] | 2624 | sa->running_avg_sum += delta * scale_freq |
| 2625 | >> SCHED_CAPACITY_SHIFT; |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2626 | sa->avg_period += delta; |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2627 | |
| 2628 | return decayed; |
| 2629 | } |
| 2630 | |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2631 | /* Synchronize an entity's decay with its parenting cfs_rq.*/ |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2632 | static inline u64 __synchronize_entity_decay(struct sched_entity *se) |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2633 | { |
| 2634 | struct cfs_rq *cfs_rq = cfs_rq_of(se); |
| 2635 | u64 decays = atomic64_read(&cfs_rq->decay_counter); |
| 2636 | |
| 2637 | decays -= se->avg.decay_count; |
Xunlei Pang | 6384760 | 2014-12-16 23:58:29 +0800 | [diff] [blame] | 2638 | se->avg.decay_count = 0; |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2639 | if (!decays) |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2640 | return 0; |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2641 | |
| 2642 | se->avg.load_avg_contrib = decay_load(se->avg.load_avg_contrib, decays); |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2643 | se->avg.utilization_avg_contrib = |
| 2644 | decay_load(se->avg.utilization_avg_contrib, decays); |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2645 | |
| 2646 | return decays; |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2647 | } |
| 2648 | |
Paul Turner | c566e8e | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2649 | #ifdef CONFIG_FAIR_GROUP_SCHED |
| 2650 | static inline void __update_cfs_rq_tg_load_contrib(struct cfs_rq *cfs_rq, |
| 2651 | int force_update) |
| 2652 | { |
| 2653 | struct task_group *tg = cfs_rq->tg; |
Alex Shi | bf5b986 | 2013-06-20 10:18:54 +0800 | [diff] [blame] | 2654 | long tg_contrib; |
Paul Turner | c566e8e | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2655 | |
| 2656 | tg_contrib = cfs_rq->runnable_load_avg + cfs_rq->blocked_load_avg; |
| 2657 | tg_contrib -= cfs_rq->tg_load_contrib; |
| 2658 | |
Jason Low | 8236d90 | 2014-09-02 00:41:24 -0700 | [diff] [blame] | 2659 | if (!tg_contrib) |
| 2660 | return; |
| 2661 | |
Alex Shi | bf5b986 | 2013-06-20 10:18:54 +0800 | [diff] [blame] | 2662 | if (force_update || abs(tg_contrib) > cfs_rq->tg_load_contrib / 8) { |
| 2663 | atomic_long_add(tg_contrib, &tg->load_avg); |
Paul Turner | c566e8e | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2664 | cfs_rq->tg_load_contrib += tg_contrib; |
| 2665 | } |
| 2666 | } |
Paul Turner | 8165e14 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2667 | |
Paul Turner | bb17f65 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2668 | /* |
| 2669 | * Aggregate cfs_rq runnable averages into an equivalent task_group |
| 2670 | * representation for computing load contributions. |
| 2671 | */ |
| 2672 | static inline void __update_tg_runnable_avg(struct sched_avg *sa, |
| 2673 | struct cfs_rq *cfs_rq) |
| 2674 | { |
| 2675 | struct task_group *tg = cfs_rq->tg; |
| 2676 | long contrib; |
| 2677 | |
| 2678 | /* The fraction of a cpu used by this cfs_rq */ |
Michal Nazarewicz | 85b088e | 2013-11-10 20:42:01 +0100 | [diff] [blame] | 2679 | contrib = div_u64((u64)sa->runnable_avg_sum << NICE_0_SHIFT, |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2680 | sa->avg_period + 1); |
Paul Turner | bb17f65 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2681 | contrib -= cfs_rq->tg_runnable_contrib; |
| 2682 | |
| 2683 | if (abs(contrib) > cfs_rq->tg_runnable_contrib / 64) { |
| 2684 | atomic_add(contrib, &tg->runnable_avg); |
| 2685 | cfs_rq->tg_runnable_contrib += contrib; |
| 2686 | } |
| 2687 | } |
| 2688 | |
Paul Turner | 8165e14 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2689 | static inline void __update_group_entity_contrib(struct sched_entity *se) |
| 2690 | { |
| 2691 | struct cfs_rq *cfs_rq = group_cfs_rq(se); |
| 2692 | struct task_group *tg = cfs_rq->tg; |
Paul Turner | bb17f65 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2693 | int runnable_avg; |
| 2694 | |
Paul Turner | 8165e14 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2695 | u64 contrib; |
| 2696 | |
| 2697 | contrib = cfs_rq->tg_load_contrib * tg->shares; |
Alex Shi | bf5b986 | 2013-06-20 10:18:54 +0800 | [diff] [blame] | 2698 | se->avg.load_avg_contrib = div_u64(contrib, |
| 2699 | atomic_long_read(&tg->load_avg) + 1); |
Paul Turner | bb17f65 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2700 | |
| 2701 | /* |
| 2702 | * For group entities we need to compute a correction term in the case |
| 2703 | * that they are consuming <1 cpu so that we would contribute the same |
| 2704 | * load as a task of equal weight. |
| 2705 | * |
| 2706 | * Explicitly co-ordinating this measurement would be expensive, but |
| 2707 | * fortunately the sum of each cpus contribution forms a usable |
| 2708 | * lower-bound on the true value. |
| 2709 | * |
| 2710 | * Consider the aggregate of 2 contributions. Either they are disjoint |
| 2711 | * (and the sum represents true value) or they are disjoint and we are |
| 2712 | * understating by the aggregate of their overlap. |
| 2713 | * |
| 2714 | * Extending this to N cpus, for a given overlap, the maximum amount we |
| 2715 | * understand is then n_i(n_i+1)/2 * w_i where n_i is the number of |
| 2716 | * cpus that overlap for this interval and w_i is the interval width. |
| 2717 | * |
| 2718 | * On a small machine; the first term is well-bounded which bounds the |
| 2719 | * total error since w_i is a subset of the period. Whereas on a |
| 2720 | * larger machine, while this first term can be larger, if w_i is the |
| 2721 | * of consequential size guaranteed to see n_i*w_i quickly converge to |
| 2722 | * our upper bound of 1-cpu. |
| 2723 | */ |
| 2724 | runnable_avg = atomic_read(&tg->runnable_avg); |
| 2725 | if (runnable_avg < NICE_0_LOAD) { |
| 2726 | se->avg.load_avg_contrib *= runnable_avg; |
| 2727 | se->avg.load_avg_contrib >>= NICE_0_SHIFT; |
| 2728 | } |
Paul Turner | 8165e14 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2729 | } |
Dietmar Eggemann | f5f9739 | 2014-02-26 11:19:33 +0000 | [diff] [blame] | 2730 | |
| 2731 | static inline void update_rq_runnable_avg(struct rq *rq, int runnable) |
| 2732 | { |
Morten Rasmussen | 0c1dc6b | 2015-03-04 08:46:26 +0100 | [diff] [blame] | 2733 | __update_entity_runnable_avg(rq_clock_task(rq), cpu_of(rq), &rq->avg, |
| 2734 | runnable, runnable); |
Dietmar Eggemann | f5f9739 | 2014-02-26 11:19:33 +0000 | [diff] [blame] | 2735 | __update_tg_runnable_avg(&rq->avg, &rq->cfs); |
| 2736 | } |
Peter Zijlstra | 6e83125 | 2014-02-11 16:11:48 +0100 | [diff] [blame] | 2737 | #else /* CONFIG_FAIR_GROUP_SCHED */ |
Paul Turner | c566e8e | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2738 | static inline void __update_cfs_rq_tg_load_contrib(struct cfs_rq *cfs_rq, |
| 2739 | int force_update) {} |
Paul Turner | bb17f65 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2740 | static inline void __update_tg_runnable_avg(struct sched_avg *sa, |
| 2741 | struct cfs_rq *cfs_rq) {} |
Paul Turner | 8165e14 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2742 | static inline void __update_group_entity_contrib(struct sched_entity *se) {} |
Dietmar Eggemann | f5f9739 | 2014-02-26 11:19:33 +0000 | [diff] [blame] | 2743 | static inline void update_rq_runnable_avg(struct rq *rq, int runnable) {} |
Peter Zijlstra | 6e83125 | 2014-02-11 16:11:48 +0100 | [diff] [blame] | 2744 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
Paul Turner | c566e8e | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2745 | |
Paul Turner | 8165e14 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2746 | static inline void __update_task_entity_contrib(struct sched_entity *se) |
| 2747 | { |
| 2748 | u32 contrib; |
| 2749 | |
| 2750 | /* avoid overflowing a 32-bit type w/ SCHED_LOAD_SCALE */ |
| 2751 | contrib = se->avg.runnable_avg_sum * scale_load_down(se->load.weight); |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2752 | contrib /= (se->avg.avg_period + 1); |
Paul Turner | 8165e14 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2753 | se->avg.load_avg_contrib = scale_load(contrib); |
| 2754 | } |
| 2755 | |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2756 | /* Compute the current contribution to load_avg by se, return any delta */ |
| 2757 | static long __update_entity_load_avg_contrib(struct sched_entity *se) |
| 2758 | { |
| 2759 | long old_contrib = se->avg.load_avg_contrib; |
| 2760 | |
Paul Turner | 8165e14 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2761 | if (entity_is_task(se)) { |
| 2762 | __update_task_entity_contrib(se); |
| 2763 | } else { |
Paul Turner | bb17f65 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2764 | __update_tg_runnable_avg(&se->avg, group_cfs_rq(se)); |
Paul Turner | 8165e14 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2765 | __update_group_entity_contrib(se); |
| 2766 | } |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2767 | |
| 2768 | return se->avg.load_avg_contrib - old_contrib; |
| 2769 | } |
| 2770 | |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2771 | |
| 2772 | static inline void __update_task_entity_utilization(struct sched_entity *se) |
| 2773 | { |
| 2774 | u32 contrib; |
| 2775 | |
| 2776 | /* avoid overflowing a 32-bit type w/ SCHED_LOAD_SCALE */ |
| 2777 | contrib = se->avg.running_avg_sum * scale_load_down(SCHED_LOAD_SCALE); |
| 2778 | contrib /= (se->avg.avg_period + 1); |
| 2779 | se->avg.utilization_avg_contrib = scale_load(contrib); |
| 2780 | } |
| 2781 | |
| 2782 | static long __update_entity_utilization_avg_contrib(struct sched_entity *se) |
| 2783 | { |
| 2784 | long old_contrib = se->avg.utilization_avg_contrib; |
| 2785 | |
| 2786 | if (entity_is_task(se)) |
| 2787 | __update_task_entity_utilization(se); |
Morten Rasmussen | 21f4486 | 2015-02-27 16:54:05 +0100 | [diff] [blame] | 2788 | else |
| 2789 | se->avg.utilization_avg_contrib = |
| 2790 | group_cfs_rq(se)->utilization_load_avg; |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2791 | |
| 2792 | return se->avg.utilization_avg_contrib - old_contrib; |
| 2793 | } |
| 2794 | |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2795 | static inline void subtract_blocked_load_contrib(struct cfs_rq *cfs_rq, |
| 2796 | long load_contrib) |
| 2797 | { |
| 2798 | if (likely(load_contrib < cfs_rq->blocked_load_avg)) |
| 2799 | cfs_rq->blocked_load_avg -= load_contrib; |
| 2800 | else |
| 2801 | cfs_rq->blocked_load_avg = 0; |
| 2802 | } |
| 2803 | |
Paul Turner | f1b1728 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2804 | static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq); |
| 2805 | |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2806 | /* Update a sched_entity's runnable average */ |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2807 | static inline void update_entity_load_avg(struct sched_entity *se, |
| 2808 | int update_cfs_rq) |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2809 | { |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2810 | struct cfs_rq *cfs_rq = cfs_rq_of(se); |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2811 | long contrib_delta, utilization_delta; |
Morten Rasmussen | 0c1dc6b | 2015-03-04 08:46:26 +0100 | [diff] [blame] | 2812 | int cpu = cpu_of(rq_of(cfs_rq)); |
Paul Turner | f1b1728 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2813 | u64 now; |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2814 | |
Paul Turner | f1b1728 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2815 | /* |
| 2816 | * For a group entity we need to use their owned cfs_rq_clock_task() in |
| 2817 | * case they are the parent of a throttled hierarchy. |
| 2818 | */ |
| 2819 | if (entity_is_task(se)) |
| 2820 | now = cfs_rq_clock_task(cfs_rq); |
| 2821 | else |
| 2822 | now = cfs_rq_clock_task(group_cfs_rq(se)); |
| 2823 | |
Morten Rasmussen | 0c1dc6b | 2015-03-04 08:46:26 +0100 | [diff] [blame] | 2824 | if (!__update_entity_runnable_avg(now, cpu, &se->avg, se->on_rq, |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2825 | cfs_rq->curr == se)) |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2826 | return; |
| 2827 | |
| 2828 | contrib_delta = __update_entity_load_avg_contrib(se); |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2829 | utilization_delta = __update_entity_utilization_avg_contrib(se); |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2830 | |
| 2831 | if (!update_cfs_rq) |
| 2832 | return; |
| 2833 | |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2834 | if (se->on_rq) { |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2835 | cfs_rq->runnable_load_avg += contrib_delta; |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2836 | cfs_rq->utilization_load_avg += utilization_delta; |
| 2837 | } else { |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2838 | subtract_blocked_load_contrib(cfs_rq, -contrib_delta); |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2839 | } |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2840 | } |
| 2841 | |
| 2842 | /* |
| 2843 | * Decay the load contributed by all blocked children and account this so that |
| 2844 | * their contribution may appropriately discounted when they wake up. |
| 2845 | */ |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2846 | static void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq, int force_update) |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2847 | { |
Paul Turner | f1b1728 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 2848 | u64 now = cfs_rq_clock_task(cfs_rq) >> 20; |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2849 | u64 decays; |
| 2850 | |
| 2851 | decays = now - cfs_rq->last_decay; |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2852 | if (!decays && !force_update) |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2853 | return; |
| 2854 | |
Alex Shi | 2509940 | 2013-06-20 10:18:55 +0800 | [diff] [blame] | 2855 | if (atomic_long_read(&cfs_rq->removed_load)) { |
| 2856 | unsigned long removed_load; |
| 2857 | removed_load = atomic_long_xchg(&cfs_rq->removed_load, 0); |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2858 | subtract_blocked_load_contrib(cfs_rq, removed_load); |
| 2859 | } |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2860 | |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2861 | if (decays) { |
| 2862 | cfs_rq->blocked_load_avg = decay_load(cfs_rq->blocked_load_avg, |
| 2863 | decays); |
| 2864 | atomic64_add(decays, &cfs_rq->decay_counter); |
| 2865 | cfs_rq->last_decay = now; |
| 2866 | } |
Paul Turner | c566e8e | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2867 | |
| 2868 | __update_cfs_rq_tg_load_contrib(cfs_rq, force_update); |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2869 | } |
Ben Segall | 18bf280 | 2012-10-04 12:51:20 +0200 | [diff] [blame] | 2870 | |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2871 | /* Add the load generated by se into cfs_rq's child load-average */ |
| 2872 | static inline void enqueue_entity_load_avg(struct cfs_rq *cfs_rq, |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2873 | struct sched_entity *se, |
| 2874 | int wakeup) |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2875 | { |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2876 | /* |
| 2877 | * We track migrations using entity decay_count <= 0, on a wake-up |
| 2878 | * migration we use a negative decay count to track the remote decays |
| 2879 | * accumulated while sleeping. |
Alex Shi | a75cdaa | 2013-06-20 10:18:47 +0800 | [diff] [blame] | 2880 | * |
| 2881 | * Newly forked tasks are enqueued with se->avg.decay_count == 0, they |
| 2882 | * are seen by enqueue_entity_load_avg() as a migration with an already |
| 2883 | * constructed load_avg_contrib. |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2884 | */ |
| 2885 | if (unlikely(se->avg.decay_count <= 0)) { |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 2886 | se->avg.last_runnable_update = rq_clock_task(rq_of(cfs_rq)); |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2887 | if (se->avg.decay_count) { |
| 2888 | /* |
| 2889 | * In a wake-up migration we have to approximate the |
| 2890 | * time sleeping. This is because we can't synchronize |
| 2891 | * clock_task between the two cpus, and it is not |
| 2892 | * guaranteed to be read-safe. Instead, we can |
| 2893 | * approximate this using our carried decays, which are |
| 2894 | * explicitly atomically readable. |
| 2895 | */ |
| 2896 | se->avg.last_runnable_update -= (-se->avg.decay_count) |
| 2897 | << 20; |
| 2898 | update_entity_load_avg(se, 0); |
| 2899 | /* Indicate that we're now synchronized and on-rq */ |
| 2900 | se->avg.decay_count = 0; |
| 2901 | } |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2902 | wakeup = 0; |
| 2903 | } else { |
Vincent Guittot | 9390675 | 2014-01-22 08:45:34 +0100 | [diff] [blame] | 2904 | __synchronize_entity_decay(se); |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2905 | } |
| 2906 | |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2907 | /* migrated tasks did not contribute to our blocked load */ |
| 2908 | if (wakeup) { |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2909 | subtract_blocked_load_contrib(cfs_rq, se->avg.load_avg_contrib); |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2910 | update_entity_load_avg(se, 0); |
| 2911 | } |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2912 | |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2913 | cfs_rq->runnable_load_avg += se->avg.load_avg_contrib; |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2914 | cfs_rq->utilization_load_avg += se->avg.utilization_avg_contrib; |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2915 | /* we force update consideration on load-balancer moves */ |
| 2916 | update_cfs_rq_blocked_load(cfs_rq, !wakeup); |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2917 | } |
| 2918 | |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2919 | /* |
| 2920 | * Remove se's load from this cfs_rq child load-average, if the entity is |
| 2921 | * transitioning to a blocked state we track its projected decay using |
| 2922 | * blocked_load_avg. |
| 2923 | */ |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2924 | static inline void dequeue_entity_load_avg(struct cfs_rq *cfs_rq, |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2925 | struct sched_entity *se, |
| 2926 | int sleep) |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2927 | { |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2928 | update_entity_load_avg(se, 1); |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2929 | /* we force update consideration on load-balancer moves */ |
| 2930 | update_cfs_rq_blocked_load(cfs_rq, !sleep); |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2931 | |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2932 | cfs_rq->runnable_load_avg -= se->avg.load_avg_contrib; |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 2933 | cfs_rq->utilization_load_avg -= se->avg.utilization_avg_contrib; |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2934 | if (sleep) { |
| 2935 | cfs_rq->blocked_load_avg += se->avg.load_avg_contrib; |
| 2936 | se->avg.decay_count = atomic64_read(&cfs_rq->decay_counter); |
| 2937 | } /* migrations, e.g. sleep=0 leave decay_count == 0 */ |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2938 | } |
Vincent Guittot | 642dbc3 | 2013-04-18 18:34:26 +0200 | [diff] [blame] | 2939 | |
| 2940 | /* |
| 2941 | * Update the rq's load with the elapsed running time before entering |
| 2942 | * idle. if the last scheduled task is not a CFS task, idle_enter will |
| 2943 | * be the only way to update the runnable statistic. |
| 2944 | */ |
| 2945 | void idle_enter_fair(struct rq *this_rq) |
| 2946 | { |
| 2947 | update_rq_runnable_avg(this_rq, 1); |
| 2948 | } |
| 2949 | |
| 2950 | /* |
| 2951 | * Update the rq's load with the elapsed idle time before a task is |
| 2952 | * scheduled. if the newly scheduled task is not a CFS task, idle_exit will |
| 2953 | * be the only way to update the runnable statistic. |
| 2954 | */ |
| 2955 | void idle_exit_fair(struct rq *this_rq) |
| 2956 | { |
| 2957 | update_rq_runnable_avg(this_rq, 0); |
| 2958 | } |
| 2959 | |
Peter Zijlstra | 6e83125 | 2014-02-11 16:11:48 +0100 | [diff] [blame] | 2960 | static int idle_balance(struct rq *this_rq); |
| 2961 | |
Peter Zijlstra | 38033c3 | 2014-01-23 20:32:21 +0100 | [diff] [blame] | 2962 | #else /* CONFIG_SMP */ |
| 2963 | |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2964 | static inline void update_entity_load_avg(struct sched_entity *se, |
| 2965 | int update_cfs_rq) {} |
Ben Segall | 18bf280 | 2012-10-04 12:51:20 +0200 | [diff] [blame] | 2966 | static inline void update_rq_runnable_avg(struct rq *rq, int runnable) {} |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2967 | static inline void enqueue_entity_load_avg(struct cfs_rq *cfs_rq, |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2968 | struct sched_entity *se, |
| 2969 | int wakeup) {} |
Paul Turner | 2dac754 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2970 | static inline void dequeue_entity_load_avg(struct cfs_rq *cfs_rq, |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2971 | struct sched_entity *se, |
| 2972 | int sleep) {} |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 2973 | static inline void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq, |
| 2974 | int force_update) {} |
Peter Zijlstra | 6e83125 | 2014-02-11 16:11:48 +0100 | [diff] [blame] | 2975 | |
| 2976 | static inline int idle_balance(struct rq *rq) |
| 2977 | { |
| 2978 | return 0; |
| 2979 | } |
| 2980 | |
Peter Zijlstra | 38033c3 | 2014-01-23 20:32:21 +0100 | [diff] [blame] | 2981 | #endif /* CONFIG_SMP */ |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 2982 | |
Ingo Molnar | 2396af6 | 2007-08-09 11:16:48 +0200 | [diff] [blame] | 2983 | static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 2984 | { |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 2985 | #ifdef CONFIG_SCHEDSTATS |
Peter Zijlstra | e414314 | 2009-07-23 20:13:26 +0200 | [diff] [blame] | 2986 | struct task_struct *tsk = NULL; |
| 2987 | |
| 2988 | if (entity_is_task(se)) |
| 2989 | tsk = task_of(se); |
| 2990 | |
Lucas De Marchi | 41acab8 | 2010-03-10 23:37:45 -0300 | [diff] [blame] | 2991 | if (se->statistics.sleep_start) { |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 2992 | u64 delta = rq_clock(rq_of(cfs_rq)) - se->statistics.sleep_start; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 2993 | |
| 2994 | if ((s64)delta < 0) |
| 2995 | delta = 0; |
| 2996 | |
Lucas De Marchi | 41acab8 | 2010-03-10 23:37:45 -0300 | [diff] [blame] | 2997 | if (unlikely(delta > se->statistics.sleep_max)) |
| 2998 | se->statistics.sleep_max = delta; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 2999 | |
Peter Zijlstra | 8c79a04 | 2012-01-30 14:51:37 +0100 | [diff] [blame] | 3000 | se->statistics.sleep_start = 0; |
Lucas De Marchi | 41acab8 | 2010-03-10 23:37:45 -0300 | [diff] [blame] | 3001 | se->statistics.sum_sleep_runtime += delta; |
Arjan van de Ven | 9745512 | 2008-01-25 21:08:34 +0100 | [diff] [blame] | 3002 | |
Peter Zijlstra | 768d0c2 | 2009-07-23 20:13:26 +0200 | [diff] [blame] | 3003 | if (tsk) { |
Peter Zijlstra | e414314 | 2009-07-23 20:13:26 +0200 | [diff] [blame] | 3004 | account_scheduler_latency(tsk, delta >> 10, 1); |
Peter Zijlstra | 768d0c2 | 2009-07-23 20:13:26 +0200 | [diff] [blame] | 3005 | trace_sched_stat_sleep(tsk, delta); |
| 3006 | } |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3007 | } |
Lucas De Marchi | 41acab8 | 2010-03-10 23:37:45 -0300 | [diff] [blame] | 3008 | if (se->statistics.block_start) { |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 3009 | u64 delta = rq_clock(rq_of(cfs_rq)) - se->statistics.block_start; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3010 | |
| 3011 | if ((s64)delta < 0) |
| 3012 | delta = 0; |
| 3013 | |
Lucas De Marchi | 41acab8 | 2010-03-10 23:37:45 -0300 | [diff] [blame] | 3014 | if (unlikely(delta > se->statistics.block_max)) |
| 3015 | se->statistics.block_max = delta; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3016 | |
Peter Zijlstra | 8c79a04 | 2012-01-30 14:51:37 +0100 | [diff] [blame] | 3017 | se->statistics.block_start = 0; |
Lucas De Marchi | 41acab8 | 2010-03-10 23:37:45 -0300 | [diff] [blame] | 3018 | se->statistics.sum_sleep_runtime += delta; |
Ingo Molnar | 30084fb | 2007-10-02 14:13:08 +0200 | [diff] [blame] | 3019 | |
Peter Zijlstra | e414314 | 2009-07-23 20:13:26 +0200 | [diff] [blame] | 3020 | if (tsk) { |
Arjan van de Ven | 8f0dfc3 | 2009-07-20 11:26:58 -0700 | [diff] [blame] | 3021 | if (tsk->in_iowait) { |
Lucas De Marchi | 41acab8 | 2010-03-10 23:37:45 -0300 | [diff] [blame] | 3022 | se->statistics.iowait_sum += delta; |
| 3023 | se->statistics.iowait_count++; |
Peter Zijlstra | 768d0c2 | 2009-07-23 20:13:26 +0200 | [diff] [blame] | 3024 | trace_sched_stat_iowait(tsk, delta); |
Arjan van de Ven | 8f0dfc3 | 2009-07-20 11:26:58 -0700 | [diff] [blame] | 3025 | } |
| 3026 | |
Andrew Vagin | b781a60 | 2011-11-28 12:03:35 +0300 | [diff] [blame] | 3027 | trace_sched_stat_blocked(tsk, delta); |
| 3028 | |
Peter Zijlstra | e414314 | 2009-07-23 20:13:26 +0200 | [diff] [blame] | 3029 | /* |
| 3030 | * Blocking time is in units of nanosecs, so shift by |
| 3031 | * 20 to get a milliseconds-range estimation of the |
| 3032 | * amount of time that the task spent sleeping: |
| 3033 | */ |
| 3034 | if (unlikely(prof_on == SLEEP_PROFILING)) { |
| 3035 | profile_hits(SLEEP_PROFILING, |
| 3036 | (void *)get_wchan(tsk), |
| 3037 | delta >> 20); |
| 3038 | } |
| 3039 | account_scheduler_latency(tsk, delta >> 10, 0); |
Ingo Molnar | 30084fb | 2007-10-02 14:13:08 +0200 | [diff] [blame] | 3040 | } |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3041 | } |
| 3042 | #endif |
| 3043 | } |
| 3044 | |
Peter Zijlstra | ddc9729 | 2007-10-15 17:00:10 +0200 | [diff] [blame] | 3045 | static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se) |
| 3046 | { |
| 3047 | #ifdef CONFIG_SCHED_DEBUG |
| 3048 | s64 d = se->vruntime - cfs_rq->min_vruntime; |
| 3049 | |
| 3050 | if (d < 0) |
| 3051 | d = -d; |
| 3052 | |
| 3053 | if (d > 3*sysctl_sched_latency) |
| 3054 | schedstat_inc(cfs_rq, nr_spread_over); |
| 3055 | #endif |
| 3056 | } |
| 3057 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3058 | static void |
Peter Zijlstra | aeb73b0 | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 3059 | place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) |
| 3060 | { |
Peter Zijlstra | 1af5f73 | 2008-10-24 11:06:13 +0200 | [diff] [blame] | 3061 | u64 vruntime = cfs_rq->min_vruntime; |
Peter Zijlstra | 94dfb5e | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 3062 | |
Peter Zijlstra | 2cb8600 | 2007-11-09 22:39:37 +0100 | [diff] [blame] | 3063 | /* |
| 3064 | * The 'current' period is already promised to the current tasks, |
| 3065 | * however the extra weight of the new task will slow them down a |
| 3066 | * little, place the new task so that it fits in the slot that |
| 3067 | * stays open at the end. |
| 3068 | */ |
Peter Zijlstra | 94dfb5e | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 3069 | if (initial && sched_feat(START_DEBIT)) |
Peter Zijlstra | f9c0b09 | 2008-10-17 19:27:04 +0200 | [diff] [blame] | 3070 | vruntime += sched_vslice(cfs_rq, se); |
Peter Zijlstra | aeb73b0 | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 3071 | |
Mike Galbraith | a2e7a7e | 2009-09-18 09:19:25 +0200 | [diff] [blame] | 3072 | /* sleeps up to a single latency don't count. */ |
Mike Galbraith | 5ca9880 | 2010-03-11 17:17:17 +0100 | [diff] [blame] | 3073 | if (!initial) { |
Mike Galbraith | a2e7a7e | 2009-09-18 09:19:25 +0200 | [diff] [blame] | 3074 | unsigned long thresh = sysctl_sched_latency; |
Peter Zijlstra | a7be37a | 2008-06-27 13:41:11 +0200 | [diff] [blame] | 3075 | |
Mike Galbraith | a2e7a7e | 2009-09-18 09:19:25 +0200 | [diff] [blame] | 3076 | /* |
Mike Galbraith | a2e7a7e | 2009-09-18 09:19:25 +0200 | [diff] [blame] | 3077 | * Halve their sleep time's effect, to allow |
| 3078 | * for a gentler effect of sleepers: |
| 3079 | */ |
| 3080 | if (sched_feat(GENTLE_FAIR_SLEEPERS)) |
| 3081 | thresh >>= 1; |
Ingo Molnar | 51e0304 | 2009-09-16 08:54:45 +0200 | [diff] [blame] | 3082 | |
Mike Galbraith | a2e7a7e | 2009-09-18 09:19:25 +0200 | [diff] [blame] | 3083 | vruntime -= thresh; |
Peter Zijlstra | aeb73b0 | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 3084 | } |
| 3085 | |
Mike Galbraith | b5d9d73 | 2009-09-08 11:12:28 +0200 | [diff] [blame] | 3086 | /* ensure we never gain time by being placed backwards. */ |
Viresh Kumar | 16c8f1c | 2012-11-08 13:33:46 +0530 | [diff] [blame] | 3087 | se->vruntime = max_vruntime(se->vruntime, vruntime); |
Peter Zijlstra | aeb73b0 | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 3088 | } |
| 3089 | |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 3090 | static void check_enqueue_throttle(struct cfs_rq *cfs_rq); |
| 3091 | |
Peter Zijlstra | aeb73b0 | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 3092 | static void |
Peter Zijlstra | 88ec22d | 2009-12-16 18:04:41 +0100 | [diff] [blame] | 3093 | enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3094 | { |
| 3095 | /* |
Peter Zijlstra | 88ec22d | 2009-12-16 18:04:41 +0100 | [diff] [blame] | 3096 | * Update the normalized vruntime before updating min_vruntime |
Kamalesh Babulal | 0fc576d | 2013-06-27 11:24:18 +0530 | [diff] [blame] | 3097 | * through calling update_curr(). |
Peter Zijlstra | 88ec22d | 2009-12-16 18:04:41 +0100 | [diff] [blame] | 3098 | */ |
Peter Zijlstra | 371fd7e | 2010-03-24 16:38:48 +0100 | [diff] [blame] | 3099 | if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING)) |
Peter Zijlstra | 88ec22d | 2009-12-16 18:04:41 +0100 | [diff] [blame] | 3100 | se->vruntime += cfs_rq->min_vruntime; |
| 3101 | |
| 3102 | /* |
Dmitry Adamushko | a2a2d68 | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 3103 | * Update run-time statistics of the 'current'. |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3104 | */ |
Ingo Molnar | b7cc089 | 2007-08-09 11:16:47 +0200 | [diff] [blame] | 3105 | update_curr(cfs_rq); |
Paul Turner | f269ae0 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 3106 | enqueue_entity_load_avg(cfs_rq, se, flags & ENQUEUE_WAKEUP); |
Linus Torvalds | 17bc14b | 2012-12-14 07:20:43 -0800 | [diff] [blame] | 3107 | account_entity_enqueue(cfs_rq, se); |
| 3108 | update_cfs_shares(cfs_rq); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3109 | |
Peter Zijlstra | 88ec22d | 2009-12-16 18:04:41 +0100 | [diff] [blame] | 3110 | if (flags & ENQUEUE_WAKEUP) { |
Peter Zijlstra | aeb73b0 | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 3111 | place_entity(cfs_rq, se, 0); |
Ingo Molnar | 2396af6 | 2007-08-09 11:16:48 +0200 | [diff] [blame] | 3112 | enqueue_sleeper(cfs_rq, se); |
Ingo Molnar | e9acbff | 2007-10-15 17:00:04 +0200 | [diff] [blame] | 3113 | } |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3114 | |
Ingo Molnar | d2417e5 | 2007-08-09 11:16:47 +0200 | [diff] [blame] | 3115 | update_stats_enqueue(cfs_rq, se); |
Peter Zijlstra | ddc9729 | 2007-10-15 17:00:10 +0200 | [diff] [blame] | 3116 | check_spread(cfs_rq, se); |
Srivatsa Vaddagiri | 83b699e | 2007-10-15 17:00:08 +0200 | [diff] [blame] | 3117 | if (se != cfs_rq->curr) |
| 3118 | __enqueue_entity(cfs_rq, se); |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 3119 | se->on_rq = 1; |
Peter Zijlstra | 3d4b47b | 2010-11-15 15:47:01 -0800 | [diff] [blame] | 3120 | |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 3121 | if (cfs_rq->nr_running == 1) { |
Peter Zijlstra | 3d4b47b | 2010-11-15 15:47:01 -0800 | [diff] [blame] | 3122 | list_add_leaf_cfs_rq(cfs_rq); |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 3123 | check_enqueue_throttle(cfs_rq); |
| 3124 | } |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3125 | } |
| 3126 | |
Rik van Riel | 2c13c919 | 2011-02-01 09:48:37 -0500 | [diff] [blame] | 3127 | static void __clear_buddies_last(struct sched_entity *se) |
Peter Zijlstra | 2002c69 | 2008-11-11 11:52:33 +0100 | [diff] [blame] | 3128 | { |
Rik van Riel | 2c13c919 | 2011-02-01 09:48:37 -0500 | [diff] [blame] | 3129 | for_each_sched_entity(se) { |
| 3130 | struct cfs_rq *cfs_rq = cfs_rq_of(se); |
Peter Zijlstra | f104479 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 3131 | if (cfs_rq->last != se) |
Rik van Riel | 2c13c919 | 2011-02-01 09:48:37 -0500 | [diff] [blame] | 3132 | break; |
Peter Zijlstra | f104479 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 3133 | |
| 3134 | cfs_rq->last = NULL; |
Rik van Riel | 2c13c919 | 2011-02-01 09:48:37 -0500 | [diff] [blame] | 3135 | } |
| 3136 | } |
Peter Zijlstra | 2002c69 | 2008-11-11 11:52:33 +0100 | [diff] [blame] | 3137 | |
Rik van Riel | 2c13c919 | 2011-02-01 09:48:37 -0500 | [diff] [blame] | 3138 | static void __clear_buddies_next(struct sched_entity *se) |
| 3139 | { |
| 3140 | for_each_sched_entity(se) { |
| 3141 | struct cfs_rq *cfs_rq = cfs_rq_of(se); |
Peter Zijlstra | f104479 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 3142 | if (cfs_rq->next != se) |
Rik van Riel | 2c13c919 | 2011-02-01 09:48:37 -0500 | [diff] [blame] | 3143 | break; |
Peter Zijlstra | f104479 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 3144 | |
| 3145 | cfs_rq->next = NULL; |
Rik van Riel | 2c13c919 | 2011-02-01 09:48:37 -0500 | [diff] [blame] | 3146 | } |
Peter Zijlstra | 2002c69 | 2008-11-11 11:52:33 +0100 | [diff] [blame] | 3147 | } |
| 3148 | |
Rik van Riel | ac53db5 | 2011-02-01 09:51:03 -0500 | [diff] [blame] | 3149 | static void __clear_buddies_skip(struct sched_entity *se) |
| 3150 | { |
| 3151 | for_each_sched_entity(se) { |
| 3152 | struct cfs_rq *cfs_rq = cfs_rq_of(se); |
Peter Zijlstra | f104479 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 3153 | if (cfs_rq->skip != se) |
Rik van Riel | ac53db5 | 2011-02-01 09:51:03 -0500 | [diff] [blame] | 3154 | break; |
Peter Zijlstra | f104479 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 3155 | |
| 3156 | cfs_rq->skip = NULL; |
Rik van Riel | ac53db5 | 2011-02-01 09:51:03 -0500 | [diff] [blame] | 3157 | } |
| 3158 | } |
| 3159 | |
Peter Zijlstra | a571bbe | 2009-01-28 14:51:40 +0100 | [diff] [blame] | 3160 | static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) |
| 3161 | { |
Rik van Riel | 2c13c919 | 2011-02-01 09:48:37 -0500 | [diff] [blame] | 3162 | if (cfs_rq->last == se) |
| 3163 | __clear_buddies_last(se); |
| 3164 | |
| 3165 | if (cfs_rq->next == se) |
| 3166 | __clear_buddies_next(se); |
Rik van Riel | ac53db5 | 2011-02-01 09:51:03 -0500 | [diff] [blame] | 3167 | |
| 3168 | if (cfs_rq->skip == se) |
| 3169 | __clear_buddies_skip(se); |
Peter Zijlstra | a571bbe | 2009-01-28 14:51:40 +0100 | [diff] [blame] | 3170 | } |
| 3171 | |
Peter Zijlstra | 6c16a6d | 2012-03-21 13:07:16 -0700 | [diff] [blame] | 3172 | static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq); |
Paul Turner | d8b4986 | 2011-07-21 09:43:41 -0700 | [diff] [blame] | 3173 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3174 | static void |
Peter Zijlstra | 371fd7e | 2010-03-24 16:38:48 +0100 | [diff] [blame] | 3175 | dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3176 | { |
Dmitry Adamushko | a2a2d68 | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 3177 | /* |
| 3178 | * Update run-time statistics of the 'current'. |
| 3179 | */ |
| 3180 | update_curr(cfs_rq); |
Linus Torvalds | 17bc14b | 2012-12-14 07:20:43 -0800 | [diff] [blame] | 3181 | dequeue_entity_load_avg(cfs_rq, se, flags & DEQUEUE_SLEEP); |
Dmitry Adamushko | a2a2d68 | 2007-10-15 17:00:13 +0200 | [diff] [blame] | 3182 | |
Ingo Molnar | 19b6a2e | 2007-08-09 11:16:48 +0200 | [diff] [blame] | 3183 | update_stats_dequeue(cfs_rq, se); |
Peter Zijlstra | 371fd7e | 2010-03-24 16:38:48 +0100 | [diff] [blame] | 3184 | if (flags & DEQUEUE_SLEEP) { |
Peter Zijlstra | 67e9fb2 | 2007-10-15 17:00:10 +0200 | [diff] [blame] | 3185 | #ifdef CONFIG_SCHEDSTATS |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3186 | if (entity_is_task(se)) { |
| 3187 | struct task_struct *tsk = task_of(se); |
| 3188 | |
| 3189 | if (tsk->state & TASK_INTERRUPTIBLE) |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 3190 | se->statistics.sleep_start = rq_clock(rq_of(cfs_rq)); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3191 | if (tsk->state & TASK_UNINTERRUPTIBLE) |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 3192 | se->statistics.block_start = rq_clock(rq_of(cfs_rq)); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3193 | } |
Dmitry Adamushko | db36cc7 | 2007-10-15 17:00:06 +0200 | [diff] [blame] | 3194 | #endif |
Peter Zijlstra | 67e9fb2 | 2007-10-15 17:00:10 +0200 | [diff] [blame] | 3195 | } |
| 3196 | |
Peter Zijlstra | 2002c69 | 2008-11-11 11:52:33 +0100 | [diff] [blame] | 3197 | clear_buddies(cfs_rq, se); |
Peter Zijlstra | 4793241 | 2008-11-04 21:25:09 +0100 | [diff] [blame] | 3198 | |
Srivatsa Vaddagiri | 83b699e | 2007-10-15 17:00:08 +0200 | [diff] [blame] | 3199 | if (se != cfs_rq->curr) |
Dmitry Adamushko | 30cfdcf | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 3200 | __dequeue_entity(cfs_rq, se); |
Linus Torvalds | 17bc14b | 2012-12-14 07:20:43 -0800 | [diff] [blame] | 3201 | se->on_rq = 0; |
Dmitry Adamushko | 30cfdcf | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 3202 | account_entity_dequeue(cfs_rq, se); |
Peter Zijlstra | 88ec22d | 2009-12-16 18:04:41 +0100 | [diff] [blame] | 3203 | |
| 3204 | /* |
| 3205 | * Normalize the entity after updating the min_vruntime because the |
| 3206 | * update can refer to the ->curr item and we need to reflect this |
| 3207 | * movement in our normalized position. |
| 3208 | */ |
Peter Zijlstra | 371fd7e | 2010-03-24 16:38:48 +0100 | [diff] [blame] | 3209 | if (!(flags & DEQUEUE_SLEEP)) |
Peter Zijlstra | 88ec22d | 2009-12-16 18:04:41 +0100 | [diff] [blame] | 3210 | se->vruntime -= cfs_rq->min_vruntime; |
Peter Zijlstra | 1e87623 | 2011-05-17 16:21:10 -0700 | [diff] [blame] | 3211 | |
Paul Turner | d8b4986 | 2011-07-21 09:43:41 -0700 | [diff] [blame] | 3212 | /* return excess runtime on last dequeue */ |
| 3213 | return_cfs_rq_runtime(cfs_rq); |
| 3214 | |
Peter Zijlstra | 1e87623 | 2011-05-17 16:21:10 -0700 | [diff] [blame] | 3215 | update_min_vruntime(cfs_rq); |
Linus Torvalds | 17bc14b | 2012-12-14 07:20:43 -0800 | [diff] [blame] | 3216 | update_cfs_shares(cfs_rq); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3217 | } |
| 3218 | |
| 3219 | /* |
| 3220 | * Preempt the current task with a newly woken task if needed: |
| 3221 | */ |
Peter Zijlstra | 7c92e54 | 2007-09-05 14:32:49 +0200 | [diff] [blame] | 3222 | static void |
Ingo Molnar | 2e09bf5 | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 3223 | check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3224 | { |
Peter Zijlstra | 1169783 | 2007-09-05 14:32:49 +0200 | [diff] [blame] | 3225 | unsigned long ideal_runtime, delta_exec; |
Wang Xingchao | f4cfb33 | 2011-09-16 13:35:52 -0400 | [diff] [blame] | 3226 | struct sched_entity *se; |
| 3227 | s64 delta; |
Peter Zijlstra | 1169783 | 2007-09-05 14:32:49 +0200 | [diff] [blame] | 3228 | |
Peter Zijlstra | 6d0f0eb | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 3229 | ideal_runtime = sched_slice(cfs_rq, curr); |
Peter Zijlstra | 1169783 | 2007-09-05 14:32:49 +0200 | [diff] [blame] | 3230 | delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; |
Mike Galbraith | a9f3e2b | 2009-01-28 14:51:39 +0100 | [diff] [blame] | 3231 | if (delta_exec > ideal_runtime) { |
Kirill Tkhai | 8875125 | 2014-06-29 00:03:57 +0400 | [diff] [blame] | 3232 | resched_curr(rq_of(cfs_rq)); |
Mike Galbraith | a9f3e2b | 2009-01-28 14:51:39 +0100 | [diff] [blame] | 3233 | /* |
| 3234 | * The current task ran long enough, ensure it doesn't get |
| 3235 | * re-elected due to buddy favours. |
| 3236 | */ |
| 3237 | clear_buddies(cfs_rq, curr); |
Mike Galbraith | f685cea | 2009-10-23 23:09:22 +0200 | [diff] [blame] | 3238 | return; |
| 3239 | } |
| 3240 | |
| 3241 | /* |
| 3242 | * Ensure that a task that missed wakeup preemption by a |
| 3243 | * narrow margin doesn't have to wait for a full slice. |
| 3244 | * This also mitigates buddy induced latencies under load. |
| 3245 | */ |
Mike Galbraith | f685cea | 2009-10-23 23:09:22 +0200 | [diff] [blame] | 3246 | if (delta_exec < sysctl_sched_min_granularity) |
| 3247 | return; |
| 3248 | |
Wang Xingchao | f4cfb33 | 2011-09-16 13:35:52 -0400 | [diff] [blame] | 3249 | se = __pick_first_entity(cfs_rq); |
| 3250 | delta = curr->vruntime - se->vruntime; |
Mike Galbraith | f685cea | 2009-10-23 23:09:22 +0200 | [diff] [blame] | 3251 | |
Wang Xingchao | f4cfb33 | 2011-09-16 13:35:52 -0400 | [diff] [blame] | 3252 | if (delta < 0) |
| 3253 | return; |
Mike Galbraith | d7d8294 | 2011-01-05 05:41:17 +0100 | [diff] [blame] | 3254 | |
Wang Xingchao | f4cfb33 | 2011-09-16 13:35:52 -0400 | [diff] [blame] | 3255 | if (delta > ideal_runtime) |
Kirill Tkhai | 8875125 | 2014-06-29 00:03:57 +0400 | [diff] [blame] | 3256 | resched_curr(rq_of(cfs_rq)); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3257 | } |
| 3258 | |
Srivatsa Vaddagiri | 83b699e | 2007-10-15 17:00:08 +0200 | [diff] [blame] | 3259 | static void |
Ingo Molnar | 8494f41 | 2007-08-09 11:16:48 +0200 | [diff] [blame] | 3260 | set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3261 | { |
Srivatsa Vaddagiri | 83b699e | 2007-10-15 17:00:08 +0200 | [diff] [blame] | 3262 | /* 'current' is not kept within the tree. */ |
| 3263 | if (se->on_rq) { |
| 3264 | /* |
| 3265 | * Any task has to be enqueued before it get to execute on |
| 3266 | * a CPU. So account for the time it spent waiting on the |
| 3267 | * runqueue. |
| 3268 | */ |
| 3269 | update_stats_wait_end(cfs_rq, se); |
| 3270 | __dequeue_entity(cfs_rq, se); |
Vincent Guittot | 36ee28e | 2015-02-27 16:54:04 +0100 | [diff] [blame] | 3271 | update_entity_load_avg(se, 1); |
Srivatsa Vaddagiri | 83b699e | 2007-10-15 17:00:08 +0200 | [diff] [blame] | 3272 | } |
| 3273 | |
Ingo Molnar | 79303e9 | 2007-08-09 11:16:47 +0200 | [diff] [blame] | 3274 | update_stats_curr_start(cfs_rq, se); |
Ingo Molnar | 429d43b | 2007-10-15 17:00:03 +0200 | [diff] [blame] | 3275 | cfs_rq->curr = se; |
Ingo Molnar | eba1ed4 | 2007-10-15 17:00:02 +0200 | [diff] [blame] | 3276 | #ifdef CONFIG_SCHEDSTATS |
| 3277 | /* |
| 3278 | * Track our maximum slice length, if the CPU's load is at |
| 3279 | * least twice that of our own weight (i.e. dont track it |
| 3280 | * when there are only lesser-weight tasks around): |
| 3281 | */ |
Dmitry Adamushko | 495eca4 | 2007-10-15 17:00:06 +0200 | [diff] [blame] | 3282 | if (rq_of(cfs_rq)->load.weight >= 2*se->load.weight) { |
Lucas De Marchi | 41acab8 | 2010-03-10 23:37:45 -0300 | [diff] [blame] | 3283 | se->statistics.slice_max = max(se->statistics.slice_max, |
Ingo Molnar | eba1ed4 | 2007-10-15 17:00:02 +0200 | [diff] [blame] | 3284 | se->sum_exec_runtime - se->prev_sum_exec_runtime); |
| 3285 | } |
| 3286 | #endif |
Peter Zijlstra | 4a55b45 | 2007-09-05 14:32:49 +0200 | [diff] [blame] | 3287 | se->prev_sum_exec_runtime = se->sum_exec_runtime; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3288 | } |
| 3289 | |
Peter Zijlstra | 3f3a490 | 2008-10-24 11:06:16 +0200 | [diff] [blame] | 3290 | static int |
| 3291 | wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se); |
| 3292 | |
Rik van Riel | ac53db5 | 2011-02-01 09:51:03 -0500 | [diff] [blame] | 3293 | /* |
| 3294 | * Pick the next process, keeping these things in mind, in this order: |
| 3295 | * 1) keep things fair between processes/task groups |
| 3296 | * 2) pick the "next" process, since someone really wants that to run |
| 3297 | * 3) pick the "last" process, for cache locality |
| 3298 | * 4) do not run the "skip" process, if something else is available |
| 3299 | */ |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 3300 | static struct sched_entity * |
| 3301 | pick_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *curr) |
Peter Zijlstra | aa2ac25 | 2008-03-14 21:12:12 +0100 | [diff] [blame] | 3302 | { |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 3303 | struct sched_entity *left = __pick_first_entity(cfs_rq); |
| 3304 | struct sched_entity *se; |
| 3305 | |
| 3306 | /* |
| 3307 | * If curr is set we have to see if its left of the leftmost entity |
| 3308 | * still in the tree, provided there was anything in the tree at all. |
| 3309 | */ |
| 3310 | if (!left || (curr && entity_before(curr, left))) |
| 3311 | left = curr; |
| 3312 | |
| 3313 | se = left; /* ideally we run the leftmost entity */ |
Peter Zijlstra | f4b6755 | 2008-11-04 21:25:07 +0100 | [diff] [blame] | 3314 | |
Rik van Riel | ac53db5 | 2011-02-01 09:51:03 -0500 | [diff] [blame] | 3315 | /* |
| 3316 | * Avoid running the skip buddy, if running something else can |
| 3317 | * be done without getting too unfair. |
| 3318 | */ |
| 3319 | if (cfs_rq->skip == se) { |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 3320 | struct sched_entity *second; |
| 3321 | |
| 3322 | if (se == curr) { |
| 3323 | second = __pick_first_entity(cfs_rq); |
| 3324 | } else { |
| 3325 | second = __pick_next_entity(se); |
| 3326 | if (!second || (curr && entity_before(curr, second))) |
| 3327 | second = curr; |
| 3328 | } |
| 3329 | |
Rik van Riel | ac53db5 | 2011-02-01 09:51:03 -0500 | [diff] [blame] | 3330 | if (second && wakeup_preempt_entity(second, left) < 1) |
| 3331 | se = second; |
| 3332 | } |
Peter Zijlstra | aa2ac25 | 2008-03-14 21:12:12 +0100 | [diff] [blame] | 3333 | |
Mike Galbraith | f685cea | 2009-10-23 23:09:22 +0200 | [diff] [blame] | 3334 | /* |
| 3335 | * Prefer last buddy, try to return the CPU to a preempted task. |
| 3336 | */ |
| 3337 | if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1) |
| 3338 | se = cfs_rq->last; |
| 3339 | |
Rik van Riel | ac53db5 | 2011-02-01 09:51:03 -0500 | [diff] [blame] | 3340 | /* |
| 3341 | * Someone really wants this to run. If it's not unfair, run it. |
| 3342 | */ |
| 3343 | if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1) |
| 3344 | se = cfs_rq->next; |
| 3345 | |
Mike Galbraith | f685cea | 2009-10-23 23:09:22 +0200 | [diff] [blame] | 3346 | clear_buddies(cfs_rq, se); |
Peter Zijlstra | 4793241 | 2008-11-04 21:25:09 +0100 | [diff] [blame] | 3347 | |
| 3348 | return se; |
Peter Zijlstra | aa2ac25 | 2008-03-14 21:12:12 +0100 | [diff] [blame] | 3349 | } |
| 3350 | |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 3351 | static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq); |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 3352 | |
Ingo Molnar | ab6cde2 | 2007-08-09 11:16:48 +0200 | [diff] [blame] | 3353 | static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3354 | { |
| 3355 | /* |
| 3356 | * If still on the runqueue then deactivate_task() |
| 3357 | * was not called and update_curr() has to be done: |
| 3358 | */ |
| 3359 | if (prev->on_rq) |
Ingo Molnar | b7cc089 | 2007-08-09 11:16:47 +0200 | [diff] [blame] | 3360 | update_curr(cfs_rq); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3361 | |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 3362 | /* throttle cfs_rqs exceeding runtime */ |
| 3363 | check_cfs_rq_runtime(cfs_rq); |
| 3364 | |
Peter Zijlstra | ddc9729 | 2007-10-15 17:00:10 +0200 | [diff] [blame] | 3365 | check_spread(cfs_rq, prev); |
Dmitry Adamushko | 30cfdcf | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 3366 | if (prev->on_rq) { |
Ingo Molnar | 5870db5 | 2007-08-09 11:16:47 +0200 | [diff] [blame] | 3367 | update_stats_wait_start(cfs_rq, prev); |
Dmitry Adamushko | 30cfdcf | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 3368 | /* Put 'current' back into the tree. */ |
| 3369 | __enqueue_entity(cfs_rq, prev); |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 3370 | /* in !on_rq case, update occurred at dequeue */ |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 3371 | update_entity_load_avg(prev, 1); |
Dmitry Adamushko | 30cfdcf | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 3372 | } |
Ingo Molnar | 429d43b | 2007-10-15 17:00:03 +0200 | [diff] [blame] | 3373 | cfs_rq->curr = NULL; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3374 | } |
| 3375 | |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 3376 | static void |
| 3377 | entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3378 | { |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3379 | /* |
Dmitry Adamushko | 30cfdcf | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 3380 | * Update run-time statistics of the 'current'. |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3381 | */ |
Dmitry Adamushko | 30cfdcf | 2007-10-15 17:00:07 +0200 | [diff] [blame] | 3382 | update_curr(cfs_rq); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3383 | |
Paul Turner | 43365bd | 2010-12-15 19:10:17 -0800 | [diff] [blame] | 3384 | /* |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 3385 | * Ensure that runnable average is periodically updated. |
| 3386 | */ |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 3387 | update_entity_load_avg(curr, 1); |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 3388 | update_cfs_rq_blocked_load(cfs_rq, 1); |
Peter Zijlstra | bf0bd94 | 2013-07-26 23:48:42 +0200 | [diff] [blame] | 3389 | update_cfs_shares(cfs_rq); |
Paul Turner | 9d85f21 | 2012-10-04 13:18:29 +0200 | [diff] [blame] | 3390 | |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 3391 | #ifdef CONFIG_SCHED_HRTICK |
| 3392 | /* |
| 3393 | * queued ticks are scheduled to match the slice, so don't bother |
| 3394 | * validating it and just reschedule. |
| 3395 | */ |
Harvey Harrison | 983ed7a | 2008-04-24 18:17:55 -0700 | [diff] [blame] | 3396 | if (queued) { |
Kirill Tkhai | 8875125 | 2014-06-29 00:03:57 +0400 | [diff] [blame] | 3397 | resched_curr(rq_of(cfs_rq)); |
Harvey Harrison | 983ed7a | 2008-04-24 18:17:55 -0700 | [diff] [blame] | 3398 | return; |
| 3399 | } |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 3400 | /* |
| 3401 | * don't let the period tick interfere with the hrtick preemption |
| 3402 | */ |
| 3403 | if (!sched_feat(DOUBLE_TICK) && |
| 3404 | hrtimer_active(&rq_of(cfs_rq)->hrtick_timer)) |
| 3405 | return; |
| 3406 | #endif |
| 3407 | |
Yong Zhang | 2c2efae | 2011-07-29 16:20:33 +0800 | [diff] [blame] | 3408 | if (cfs_rq->nr_running > 1) |
Ingo Molnar | 2e09bf5 | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 3409 | check_preempt_tick(cfs_rq, curr); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3410 | } |
| 3411 | |
Paul Turner | ab84d31 | 2011-07-21 09:43:28 -0700 | [diff] [blame] | 3412 | |
| 3413 | /************************************************** |
| 3414 | * CFS bandwidth control machinery |
| 3415 | */ |
| 3416 | |
| 3417 | #ifdef CONFIG_CFS_BANDWIDTH |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 3418 | |
| 3419 | #ifdef HAVE_JUMP_LABEL |
Ingo Molnar | c5905af | 2012-02-24 08:31:31 +0100 | [diff] [blame] | 3420 | static struct static_key __cfs_bandwidth_used; |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 3421 | |
| 3422 | static inline bool cfs_bandwidth_used(void) |
| 3423 | { |
Ingo Molnar | c5905af | 2012-02-24 08:31:31 +0100 | [diff] [blame] | 3424 | return static_key_false(&__cfs_bandwidth_used); |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 3425 | } |
| 3426 | |
Ben Segall | 1ee14e6 | 2013-10-16 11:16:12 -0700 | [diff] [blame] | 3427 | void cfs_bandwidth_usage_inc(void) |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 3428 | { |
Ben Segall | 1ee14e6 | 2013-10-16 11:16:12 -0700 | [diff] [blame] | 3429 | static_key_slow_inc(&__cfs_bandwidth_used); |
| 3430 | } |
| 3431 | |
| 3432 | void cfs_bandwidth_usage_dec(void) |
| 3433 | { |
| 3434 | static_key_slow_dec(&__cfs_bandwidth_used); |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 3435 | } |
| 3436 | #else /* HAVE_JUMP_LABEL */ |
| 3437 | static bool cfs_bandwidth_used(void) |
| 3438 | { |
| 3439 | return true; |
| 3440 | } |
| 3441 | |
Ben Segall | 1ee14e6 | 2013-10-16 11:16:12 -0700 | [diff] [blame] | 3442 | void cfs_bandwidth_usage_inc(void) {} |
| 3443 | void cfs_bandwidth_usage_dec(void) {} |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 3444 | #endif /* HAVE_JUMP_LABEL */ |
| 3445 | |
Paul Turner | ab84d31 | 2011-07-21 09:43:28 -0700 | [diff] [blame] | 3446 | /* |
| 3447 | * default period for cfs group bandwidth. |
| 3448 | * default: 0.1s, units: nanoseconds |
| 3449 | */ |
| 3450 | static inline u64 default_cfs_period(void) |
| 3451 | { |
| 3452 | return 100000000ULL; |
| 3453 | } |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 3454 | |
| 3455 | static inline u64 sched_cfs_bandwidth_slice(void) |
| 3456 | { |
| 3457 | return (u64)sysctl_sched_cfs_bandwidth_slice * NSEC_PER_USEC; |
| 3458 | } |
| 3459 | |
Paul Turner | a9cf55b | 2011-07-21 09:43:32 -0700 | [diff] [blame] | 3460 | /* |
| 3461 | * Replenish runtime according to assigned quota and update expiration time. |
| 3462 | * We use sched_clock_cpu directly instead of rq->clock to avoid adding |
| 3463 | * additional synchronization around rq->lock. |
| 3464 | * |
| 3465 | * requires cfs_b->lock |
| 3466 | */ |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 3467 | void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b) |
Paul Turner | a9cf55b | 2011-07-21 09:43:32 -0700 | [diff] [blame] | 3468 | { |
| 3469 | u64 now; |
| 3470 | |
| 3471 | if (cfs_b->quota == RUNTIME_INF) |
| 3472 | return; |
| 3473 | |
| 3474 | now = sched_clock_cpu(smp_processor_id()); |
| 3475 | cfs_b->runtime = cfs_b->quota; |
| 3476 | cfs_b->runtime_expires = now + ktime_to_ns(cfs_b->period); |
| 3477 | } |
| 3478 | |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 3479 | static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg) |
| 3480 | { |
| 3481 | return &tg->cfs_bandwidth; |
| 3482 | } |
| 3483 | |
Paul Turner | f1b1728 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 3484 | /* rq->task_clock normalized against any time this cfs_rq has spent throttled */ |
| 3485 | static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq) |
| 3486 | { |
| 3487 | if (unlikely(cfs_rq->throttle_count)) |
| 3488 | return cfs_rq->throttled_clock_task; |
| 3489 | |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 3490 | return rq_clock_task(rq_of(cfs_rq)) - cfs_rq->throttled_clock_task_time; |
Paul Turner | f1b1728 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 3491 | } |
| 3492 | |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 3493 | /* returns 0 on failure to allocate runtime */ |
| 3494 | static int assign_cfs_rq_runtime(struct cfs_rq *cfs_rq) |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 3495 | { |
| 3496 | struct task_group *tg = cfs_rq->tg; |
| 3497 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(tg); |
Paul Turner | a9cf55b | 2011-07-21 09:43:32 -0700 | [diff] [blame] | 3498 | u64 amount = 0, min_amount, expires; |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 3499 | |
| 3500 | /* note: this is a positive sum as runtime_remaining <= 0 */ |
| 3501 | min_amount = sched_cfs_bandwidth_slice() - cfs_rq->runtime_remaining; |
| 3502 | |
| 3503 | raw_spin_lock(&cfs_b->lock); |
| 3504 | if (cfs_b->quota == RUNTIME_INF) |
| 3505 | amount = min_amount; |
Paul Turner | 58088ad | 2011-07-21 09:43:31 -0700 | [diff] [blame] | 3506 | else { |
Peter Zijlstra | 77a4d1a | 2015-04-15 11:41:57 +0200 | [diff] [blame] | 3507 | start_cfs_bandwidth(cfs_b); |
Paul Turner | 58088ad | 2011-07-21 09:43:31 -0700 | [diff] [blame] | 3508 | |
| 3509 | if (cfs_b->runtime > 0) { |
| 3510 | amount = min(cfs_b->runtime, min_amount); |
| 3511 | cfs_b->runtime -= amount; |
| 3512 | cfs_b->idle = 0; |
| 3513 | } |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 3514 | } |
Paul Turner | a9cf55b | 2011-07-21 09:43:32 -0700 | [diff] [blame] | 3515 | expires = cfs_b->runtime_expires; |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 3516 | raw_spin_unlock(&cfs_b->lock); |
| 3517 | |
| 3518 | cfs_rq->runtime_remaining += amount; |
Paul Turner | a9cf55b | 2011-07-21 09:43:32 -0700 | [diff] [blame] | 3519 | /* |
| 3520 | * we may have advanced our local expiration to account for allowed |
| 3521 | * spread between our sched_clock and the one on which runtime was |
| 3522 | * issued. |
| 3523 | */ |
| 3524 | if ((s64)(expires - cfs_rq->runtime_expires) > 0) |
| 3525 | cfs_rq->runtime_expires = expires; |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 3526 | |
| 3527 | return cfs_rq->runtime_remaining > 0; |
Paul Turner | a9cf55b | 2011-07-21 09:43:32 -0700 | [diff] [blame] | 3528 | } |
| 3529 | |
| 3530 | /* |
| 3531 | * Note: This depends on the synchronization provided by sched_clock and the |
| 3532 | * fact that rq->clock snapshots this value. |
| 3533 | */ |
| 3534 | static void expire_cfs_rq_runtime(struct cfs_rq *cfs_rq) |
| 3535 | { |
| 3536 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); |
Paul Turner | a9cf55b | 2011-07-21 09:43:32 -0700 | [diff] [blame] | 3537 | |
| 3538 | /* if the deadline is ahead of our clock, nothing to do */ |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 3539 | if (likely((s64)(rq_clock(rq_of(cfs_rq)) - cfs_rq->runtime_expires) < 0)) |
Paul Turner | a9cf55b | 2011-07-21 09:43:32 -0700 | [diff] [blame] | 3540 | return; |
| 3541 | |
| 3542 | if (cfs_rq->runtime_remaining < 0) |
| 3543 | return; |
| 3544 | |
| 3545 | /* |
| 3546 | * If the local deadline has passed we have to consider the |
| 3547 | * possibility that our sched_clock is 'fast' and the global deadline |
| 3548 | * has not truly expired. |
| 3549 | * |
| 3550 | * Fortunately we can check determine whether this the case by checking |
Ben Segall | 51f2176 | 2014-05-19 15:49:45 -0700 | [diff] [blame] | 3551 | * whether the global deadline has advanced. It is valid to compare |
| 3552 | * cfs_b->runtime_expires without any locks since we only care about |
| 3553 | * exact equality, so a partial write will still work. |
Paul Turner | a9cf55b | 2011-07-21 09:43:32 -0700 | [diff] [blame] | 3554 | */ |
| 3555 | |
Ben Segall | 51f2176 | 2014-05-19 15:49:45 -0700 | [diff] [blame] | 3556 | if (cfs_rq->runtime_expires != cfs_b->runtime_expires) { |
Paul Turner | a9cf55b | 2011-07-21 09:43:32 -0700 | [diff] [blame] | 3557 | /* extend local deadline, drift is bounded above by 2 ticks */ |
| 3558 | cfs_rq->runtime_expires += TICK_NSEC; |
| 3559 | } else { |
| 3560 | /* global deadline is ahead, expiration has passed */ |
| 3561 | cfs_rq->runtime_remaining = 0; |
| 3562 | } |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 3563 | } |
| 3564 | |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 3565 | static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 3566 | { |
Paul Turner | a9cf55b | 2011-07-21 09:43:32 -0700 | [diff] [blame] | 3567 | /* dock delta_exec before expiring quota (as it could span periods) */ |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 3568 | cfs_rq->runtime_remaining -= delta_exec; |
Paul Turner | a9cf55b | 2011-07-21 09:43:32 -0700 | [diff] [blame] | 3569 | expire_cfs_rq_runtime(cfs_rq); |
| 3570 | |
| 3571 | if (likely(cfs_rq->runtime_remaining > 0)) |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 3572 | return; |
| 3573 | |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 3574 | /* |
| 3575 | * if we're unable to extend our runtime we resched so that the active |
| 3576 | * hierarchy can be throttled |
| 3577 | */ |
| 3578 | if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr)) |
Kirill Tkhai | 8875125 | 2014-06-29 00:03:57 +0400 | [diff] [blame] | 3579 | resched_curr(rq_of(cfs_rq)); |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 3580 | } |
| 3581 | |
Peter Zijlstra | 6c16a6d | 2012-03-21 13:07:16 -0700 | [diff] [blame] | 3582 | static __always_inline |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 3583 | void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 3584 | { |
Paul Turner | 56f570e | 2011-11-07 20:26:33 -0800 | [diff] [blame] | 3585 | if (!cfs_bandwidth_used() || !cfs_rq->runtime_enabled) |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 3586 | return; |
| 3587 | |
| 3588 | __account_cfs_rq_runtime(cfs_rq, delta_exec); |
| 3589 | } |
| 3590 | |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 3591 | static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq) |
| 3592 | { |
Paul Turner | 56f570e | 2011-11-07 20:26:33 -0800 | [diff] [blame] | 3593 | return cfs_bandwidth_used() && cfs_rq->throttled; |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 3594 | } |
| 3595 | |
Paul Turner | 64660c8 | 2011-07-21 09:43:36 -0700 | [diff] [blame] | 3596 | /* check whether cfs_rq, or any parent, is throttled */ |
| 3597 | static inline int throttled_hierarchy(struct cfs_rq *cfs_rq) |
| 3598 | { |
Paul Turner | 56f570e | 2011-11-07 20:26:33 -0800 | [diff] [blame] | 3599 | return cfs_bandwidth_used() && cfs_rq->throttle_count; |
Paul Turner | 64660c8 | 2011-07-21 09:43:36 -0700 | [diff] [blame] | 3600 | } |
| 3601 | |
| 3602 | /* |
| 3603 | * Ensure that neither of the group entities corresponding to src_cpu or |
| 3604 | * dest_cpu are members of a throttled hierarchy when performing group |
| 3605 | * load-balance operations. |
| 3606 | */ |
| 3607 | static inline int throttled_lb_pair(struct task_group *tg, |
| 3608 | int src_cpu, int dest_cpu) |
| 3609 | { |
| 3610 | struct cfs_rq *src_cfs_rq, *dest_cfs_rq; |
| 3611 | |
| 3612 | src_cfs_rq = tg->cfs_rq[src_cpu]; |
| 3613 | dest_cfs_rq = tg->cfs_rq[dest_cpu]; |
| 3614 | |
| 3615 | return throttled_hierarchy(src_cfs_rq) || |
| 3616 | throttled_hierarchy(dest_cfs_rq); |
| 3617 | } |
| 3618 | |
| 3619 | /* updated child weight may affect parent so we have to do this bottom up */ |
| 3620 | static int tg_unthrottle_up(struct task_group *tg, void *data) |
| 3621 | { |
| 3622 | struct rq *rq = data; |
| 3623 | struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; |
| 3624 | |
| 3625 | cfs_rq->throttle_count--; |
| 3626 | #ifdef CONFIG_SMP |
| 3627 | if (!cfs_rq->throttle_count) { |
Paul Turner | f1b1728 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 3628 | /* adjust cfs_rq_clock_task() */ |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 3629 | cfs_rq->throttled_clock_task_time += rq_clock_task(rq) - |
Paul Turner | f1b1728 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 3630 | cfs_rq->throttled_clock_task; |
Paul Turner | 64660c8 | 2011-07-21 09:43:36 -0700 | [diff] [blame] | 3631 | } |
| 3632 | #endif |
| 3633 | |
| 3634 | return 0; |
| 3635 | } |
| 3636 | |
| 3637 | static int tg_throttle_down(struct task_group *tg, void *data) |
| 3638 | { |
| 3639 | struct rq *rq = data; |
| 3640 | struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; |
| 3641 | |
Paul Turner | 8295836 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 3642 | /* group is entering throttled state, stop time */ |
| 3643 | if (!cfs_rq->throttle_count) |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 3644 | cfs_rq->throttled_clock_task = rq_clock_task(rq); |
Paul Turner | 64660c8 | 2011-07-21 09:43:36 -0700 | [diff] [blame] | 3645 | cfs_rq->throttle_count++; |
| 3646 | |
| 3647 | return 0; |
| 3648 | } |
| 3649 | |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 3650 | static void throttle_cfs_rq(struct cfs_rq *cfs_rq) |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 3651 | { |
| 3652 | struct rq *rq = rq_of(cfs_rq); |
| 3653 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); |
| 3654 | struct sched_entity *se; |
| 3655 | long task_delta, dequeue = 1; |
Peter Zijlstra | 77a4d1a | 2015-04-15 11:41:57 +0200 | [diff] [blame] | 3656 | bool empty; |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 3657 | |
| 3658 | se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))]; |
| 3659 | |
Paul Turner | f1b1728 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 3660 | /* freeze hierarchy runnable averages while throttled */ |
Paul Turner | 64660c8 | 2011-07-21 09:43:36 -0700 | [diff] [blame] | 3661 | rcu_read_lock(); |
| 3662 | walk_tg_tree_from(cfs_rq->tg, tg_throttle_down, tg_nop, (void *)rq); |
| 3663 | rcu_read_unlock(); |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 3664 | |
| 3665 | task_delta = cfs_rq->h_nr_running; |
| 3666 | for_each_sched_entity(se) { |
| 3667 | struct cfs_rq *qcfs_rq = cfs_rq_of(se); |
| 3668 | /* throttled entity or throttle-on-deactivate */ |
| 3669 | if (!se->on_rq) |
| 3670 | break; |
| 3671 | |
| 3672 | if (dequeue) |
| 3673 | dequeue_entity(qcfs_rq, se, DEQUEUE_SLEEP); |
| 3674 | qcfs_rq->h_nr_running -= task_delta; |
| 3675 | |
| 3676 | if (qcfs_rq->load.weight) |
| 3677 | dequeue = 0; |
| 3678 | } |
| 3679 | |
| 3680 | if (!se) |
Kirill Tkhai | 7246544 | 2014-05-09 03:00:14 +0400 | [diff] [blame] | 3681 | sub_nr_running(rq, task_delta); |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 3682 | |
| 3683 | cfs_rq->throttled = 1; |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 3684 | cfs_rq->throttled_clock = rq_clock(rq); |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 3685 | raw_spin_lock(&cfs_b->lock); |
Cong Wang | d49db34 | 2015-06-24 12:41:47 -0700 | [diff] [blame] | 3686 | empty = list_empty(&cfs_b->throttled_cfs_rq); |
Peter Zijlstra | 77a4d1a | 2015-04-15 11:41:57 +0200 | [diff] [blame] | 3687 | |
Ben Segall | c06f04c | 2014-06-20 15:21:20 -0700 | [diff] [blame] | 3688 | /* |
| 3689 | * Add to the _head_ of the list, so that an already-started |
| 3690 | * distribute_cfs_runtime will not see us |
| 3691 | */ |
| 3692 | list_add_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq); |
Peter Zijlstra | 77a4d1a | 2015-04-15 11:41:57 +0200 | [diff] [blame] | 3693 | |
| 3694 | /* |
| 3695 | * If we're the first throttled task, make sure the bandwidth |
| 3696 | * timer is running. |
| 3697 | */ |
| 3698 | if (empty) |
| 3699 | start_cfs_bandwidth(cfs_b); |
| 3700 | |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 3701 | raw_spin_unlock(&cfs_b->lock); |
| 3702 | } |
| 3703 | |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 3704 | void unthrottle_cfs_rq(struct cfs_rq *cfs_rq) |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3705 | { |
| 3706 | struct rq *rq = rq_of(cfs_rq); |
| 3707 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); |
| 3708 | struct sched_entity *se; |
| 3709 | int enqueue = 1; |
| 3710 | long task_delta; |
| 3711 | |
Michael Wang | 22b958d | 2013-06-04 14:23:39 +0800 | [diff] [blame] | 3712 | se = cfs_rq->tg->se[cpu_of(rq)]; |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3713 | |
| 3714 | cfs_rq->throttled = 0; |
Frederic Weisbecker | 1a55af2 | 2013-04-12 01:51:01 +0200 | [diff] [blame] | 3715 | |
| 3716 | update_rq_clock(rq); |
| 3717 | |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3718 | raw_spin_lock(&cfs_b->lock); |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 3719 | cfs_b->throttled_time += rq_clock(rq) - cfs_rq->throttled_clock; |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3720 | list_del_rcu(&cfs_rq->throttled_list); |
| 3721 | raw_spin_unlock(&cfs_b->lock); |
| 3722 | |
Paul Turner | 64660c8 | 2011-07-21 09:43:36 -0700 | [diff] [blame] | 3723 | /* update hierarchical throttle state */ |
| 3724 | walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq); |
| 3725 | |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3726 | if (!cfs_rq->load.weight) |
| 3727 | return; |
| 3728 | |
| 3729 | task_delta = cfs_rq->h_nr_running; |
| 3730 | for_each_sched_entity(se) { |
| 3731 | if (se->on_rq) |
| 3732 | enqueue = 0; |
| 3733 | |
| 3734 | cfs_rq = cfs_rq_of(se); |
| 3735 | if (enqueue) |
| 3736 | enqueue_entity(cfs_rq, se, ENQUEUE_WAKEUP); |
| 3737 | cfs_rq->h_nr_running += task_delta; |
| 3738 | |
| 3739 | if (cfs_rq_throttled(cfs_rq)) |
| 3740 | break; |
| 3741 | } |
| 3742 | |
| 3743 | if (!se) |
Kirill Tkhai | 7246544 | 2014-05-09 03:00:14 +0400 | [diff] [blame] | 3744 | add_nr_running(rq, task_delta); |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3745 | |
| 3746 | /* determine whether we need to wake up potentially idle cpu */ |
| 3747 | if (rq->curr == rq->idle && rq->cfs.nr_running) |
Kirill Tkhai | 8875125 | 2014-06-29 00:03:57 +0400 | [diff] [blame] | 3748 | resched_curr(rq); |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3749 | } |
| 3750 | |
| 3751 | static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b, |
| 3752 | u64 remaining, u64 expires) |
| 3753 | { |
| 3754 | struct cfs_rq *cfs_rq; |
Ben Segall | c06f04c | 2014-06-20 15:21:20 -0700 | [diff] [blame] | 3755 | u64 runtime; |
| 3756 | u64 starting_runtime = remaining; |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3757 | |
| 3758 | rcu_read_lock(); |
| 3759 | list_for_each_entry_rcu(cfs_rq, &cfs_b->throttled_cfs_rq, |
| 3760 | throttled_list) { |
| 3761 | struct rq *rq = rq_of(cfs_rq); |
| 3762 | |
| 3763 | raw_spin_lock(&rq->lock); |
| 3764 | if (!cfs_rq_throttled(cfs_rq)) |
| 3765 | goto next; |
| 3766 | |
| 3767 | runtime = -cfs_rq->runtime_remaining + 1; |
| 3768 | if (runtime > remaining) |
| 3769 | runtime = remaining; |
| 3770 | remaining -= runtime; |
| 3771 | |
| 3772 | cfs_rq->runtime_remaining += runtime; |
| 3773 | cfs_rq->runtime_expires = expires; |
| 3774 | |
| 3775 | /* we check whether we're throttled above */ |
| 3776 | if (cfs_rq->runtime_remaining > 0) |
| 3777 | unthrottle_cfs_rq(cfs_rq); |
| 3778 | |
| 3779 | next: |
| 3780 | raw_spin_unlock(&rq->lock); |
| 3781 | |
| 3782 | if (!remaining) |
| 3783 | break; |
| 3784 | } |
| 3785 | rcu_read_unlock(); |
| 3786 | |
Ben Segall | c06f04c | 2014-06-20 15:21:20 -0700 | [diff] [blame] | 3787 | return starting_runtime - remaining; |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3788 | } |
| 3789 | |
Paul Turner | 58088ad | 2011-07-21 09:43:31 -0700 | [diff] [blame] | 3790 | /* |
| 3791 | * Responsible for refilling a task_group's bandwidth and unthrottling its |
| 3792 | * cfs_rqs as appropriate. If there has been no activity within the last |
| 3793 | * period the timer is deactivated until scheduling resumes; cfs_b->idle is |
| 3794 | * used to track this state. |
| 3795 | */ |
| 3796 | static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun) |
| 3797 | { |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3798 | u64 runtime, runtime_expires; |
Ben Segall | 51f2176 | 2014-05-19 15:49:45 -0700 | [diff] [blame] | 3799 | int throttled; |
Paul Turner | 58088ad | 2011-07-21 09:43:31 -0700 | [diff] [blame] | 3800 | |
Paul Turner | 58088ad | 2011-07-21 09:43:31 -0700 | [diff] [blame] | 3801 | /* no need to continue the timer with no bandwidth constraint */ |
| 3802 | if (cfs_b->quota == RUNTIME_INF) |
Ben Segall | 51f2176 | 2014-05-19 15:49:45 -0700 | [diff] [blame] | 3803 | goto out_deactivate; |
Paul Turner | 58088ad | 2011-07-21 09:43:31 -0700 | [diff] [blame] | 3804 | |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3805 | throttled = !list_empty(&cfs_b->throttled_cfs_rq); |
Nikhil Rao | e8da1b1 | 2011-07-21 09:43:40 -0700 | [diff] [blame] | 3806 | cfs_b->nr_periods += overrun; |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3807 | |
Ben Segall | 51f2176 | 2014-05-19 15:49:45 -0700 | [diff] [blame] | 3808 | /* |
| 3809 | * idle depends on !throttled (for the case of a large deficit), and if |
| 3810 | * we're going inactive then everything else can be deferred |
| 3811 | */ |
| 3812 | if (cfs_b->idle && !throttled) |
| 3813 | goto out_deactivate; |
Paul Turner | a9cf55b | 2011-07-21 09:43:32 -0700 | [diff] [blame] | 3814 | |
| 3815 | __refill_cfs_bandwidth_runtime(cfs_b); |
| 3816 | |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3817 | if (!throttled) { |
| 3818 | /* mark as potentially idle for the upcoming period */ |
| 3819 | cfs_b->idle = 1; |
Ben Segall | 51f2176 | 2014-05-19 15:49:45 -0700 | [diff] [blame] | 3820 | return 0; |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3821 | } |
Paul Turner | 58088ad | 2011-07-21 09:43:31 -0700 | [diff] [blame] | 3822 | |
Nikhil Rao | e8da1b1 | 2011-07-21 09:43:40 -0700 | [diff] [blame] | 3823 | /* account preceding periods in which throttling occurred */ |
| 3824 | cfs_b->nr_throttled += overrun; |
| 3825 | |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3826 | runtime_expires = cfs_b->runtime_expires; |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3827 | |
| 3828 | /* |
Ben Segall | c06f04c | 2014-06-20 15:21:20 -0700 | [diff] [blame] | 3829 | * This check is repeated as we are holding onto the new bandwidth while |
| 3830 | * we unthrottle. This can potentially race with an unthrottled group |
| 3831 | * trying to acquire new bandwidth from the global pool. This can result |
| 3832 | * in us over-using our runtime if it is all used during this loop, but |
| 3833 | * only by limited amounts in that extreme case. |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3834 | */ |
Ben Segall | c06f04c | 2014-06-20 15:21:20 -0700 | [diff] [blame] | 3835 | while (throttled && cfs_b->runtime > 0) { |
| 3836 | runtime = cfs_b->runtime; |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3837 | raw_spin_unlock(&cfs_b->lock); |
| 3838 | /* we can't nest cfs_b->lock while distributing bandwidth */ |
| 3839 | runtime = distribute_cfs_runtime(cfs_b, runtime, |
| 3840 | runtime_expires); |
| 3841 | raw_spin_lock(&cfs_b->lock); |
| 3842 | |
| 3843 | throttled = !list_empty(&cfs_b->throttled_cfs_rq); |
Ben Segall | c06f04c | 2014-06-20 15:21:20 -0700 | [diff] [blame] | 3844 | |
| 3845 | cfs_b->runtime -= min(runtime, cfs_b->runtime); |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3846 | } |
| 3847 | |
Paul Turner | 671fd9d | 2011-07-21 09:43:34 -0700 | [diff] [blame] | 3848 | /* |
| 3849 | * While we are ensured activity in the period following an |
| 3850 | * unthrottle, this also covers the case in which the new bandwidth is |
| 3851 | * insufficient to cover the existing bandwidth deficit. (Forcing the |
| 3852 | * timer to remain active while there are any throttled entities.) |
| 3853 | */ |
| 3854 | cfs_b->idle = 0; |
Paul Turner | 58088ad | 2011-07-21 09:43:31 -0700 | [diff] [blame] | 3855 | |
Ben Segall | 51f2176 | 2014-05-19 15:49:45 -0700 | [diff] [blame] | 3856 | return 0; |
| 3857 | |
| 3858 | out_deactivate: |
Ben Segall | 51f2176 | 2014-05-19 15:49:45 -0700 | [diff] [blame] | 3859 | return 1; |
Paul Turner | 58088ad | 2011-07-21 09:43:31 -0700 | [diff] [blame] | 3860 | } |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 3861 | |
Paul Turner | d8b4986 | 2011-07-21 09:43:41 -0700 | [diff] [blame] | 3862 | /* a cfs_rq won't donate quota below this amount */ |
| 3863 | static const u64 min_cfs_rq_runtime = 1 * NSEC_PER_MSEC; |
| 3864 | /* minimum remaining period time to redistribute slack quota */ |
| 3865 | static const u64 min_bandwidth_expiration = 2 * NSEC_PER_MSEC; |
| 3866 | /* how long we wait to gather additional slack before distributing */ |
| 3867 | static const u64 cfs_bandwidth_slack_period = 5 * NSEC_PER_MSEC; |
| 3868 | |
Ben Segall | db06e78 | 2013-10-16 11:16:17 -0700 | [diff] [blame] | 3869 | /* |
| 3870 | * Are we near the end of the current quota period? |
| 3871 | * |
| 3872 | * Requires cfs_b->lock for hrtimer_expires_remaining to be safe against the |
Thomas Gleixner | 4961b6e | 2015-04-14 21:09:05 +0000 | [diff] [blame] | 3873 | * hrtimer base being cleared by hrtimer_start. In the case of |
Ben Segall | db06e78 | 2013-10-16 11:16:17 -0700 | [diff] [blame] | 3874 | * migrate_hrtimers, base is never cleared, so we are fine. |
| 3875 | */ |
Paul Turner | d8b4986 | 2011-07-21 09:43:41 -0700 | [diff] [blame] | 3876 | static int runtime_refresh_within(struct cfs_bandwidth *cfs_b, u64 min_expire) |
| 3877 | { |
| 3878 | struct hrtimer *refresh_timer = &cfs_b->period_timer; |
| 3879 | u64 remaining; |
| 3880 | |
| 3881 | /* if the call-back is running a quota refresh is already occurring */ |
| 3882 | if (hrtimer_callback_running(refresh_timer)) |
| 3883 | return 1; |
| 3884 | |
| 3885 | /* is a quota refresh about to occur? */ |
| 3886 | remaining = ktime_to_ns(hrtimer_expires_remaining(refresh_timer)); |
| 3887 | if (remaining < min_expire) |
| 3888 | return 1; |
| 3889 | |
| 3890 | return 0; |
| 3891 | } |
| 3892 | |
| 3893 | static void start_cfs_slack_bandwidth(struct cfs_bandwidth *cfs_b) |
| 3894 | { |
| 3895 | u64 min_left = cfs_bandwidth_slack_period + min_bandwidth_expiration; |
| 3896 | |
| 3897 | /* if there's a quota refresh soon don't bother with slack */ |
| 3898 | if (runtime_refresh_within(cfs_b, min_left)) |
| 3899 | return; |
| 3900 | |
Peter Zijlstra | 4cfafd3 | 2015-05-14 12:23:11 +0200 | [diff] [blame] | 3901 | hrtimer_start(&cfs_b->slack_timer, |
| 3902 | ns_to_ktime(cfs_bandwidth_slack_period), |
| 3903 | HRTIMER_MODE_REL); |
Paul Turner | d8b4986 | 2011-07-21 09:43:41 -0700 | [diff] [blame] | 3904 | } |
| 3905 | |
| 3906 | /* we know any runtime found here is valid as update_curr() precedes return */ |
| 3907 | static void __return_cfs_rq_runtime(struct cfs_rq *cfs_rq) |
| 3908 | { |
| 3909 | struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); |
| 3910 | s64 slack_runtime = cfs_rq->runtime_remaining - min_cfs_rq_runtime; |
| 3911 | |
| 3912 | if (slack_runtime <= 0) |
| 3913 | return; |
| 3914 | |
| 3915 | raw_spin_lock(&cfs_b->lock); |
| 3916 | if (cfs_b->quota != RUNTIME_INF && |
| 3917 | cfs_rq->runtime_expires == cfs_b->runtime_expires) { |
| 3918 | cfs_b->runtime += slack_runtime; |
| 3919 | |
| 3920 | /* we are under rq->lock, defer unthrottling using a timer */ |
| 3921 | if (cfs_b->runtime > sched_cfs_bandwidth_slice() && |
| 3922 | !list_empty(&cfs_b->throttled_cfs_rq)) |
| 3923 | start_cfs_slack_bandwidth(cfs_b); |
| 3924 | } |
| 3925 | raw_spin_unlock(&cfs_b->lock); |
| 3926 | |
| 3927 | /* even if it's not valid for return we don't want to try again */ |
| 3928 | cfs_rq->runtime_remaining -= slack_runtime; |
| 3929 | } |
| 3930 | |
| 3931 | static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) |
| 3932 | { |
Paul Turner | 56f570e | 2011-11-07 20:26:33 -0800 | [diff] [blame] | 3933 | if (!cfs_bandwidth_used()) |
| 3934 | return; |
| 3935 | |
Paul Turner | fccfdc6 | 2011-11-07 20:26:34 -0800 | [diff] [blame] | 3936 | if (!cfs_rq->runtime_enabled || cfs_rq->nr_running) |
Paul Turner | d8b4986 | 2011-07-21 09:43:41 -0700 | [diff] [blame] | 3937 | return; |
| 3938 | |
| 3939 | __return_cfs_rq_runtime(cfs_rq); |
| 3940 | } |
| 3941 | |
| 3942 | /* |
| 3943 | * This is done with a timer (instead of inline with bandwidth return) since |
| 3944 | * it's necessary to juggle rq->locks to unthrottle their respective cfs_rqs. |
| 3945 | */ |
| 3946 | static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b) |
| 3947 | { |
| 3948 | u64 runtime = 0, slice = sched_cfs_bandwidth_slice(); |
| 3949 | u64 expires; |
| 3950 | |
| 3951 | /* confirm we're still not at a refresh boundary */ |
Paul Turner | d8b4986 | 2011-07-21 09:43:41 -0700 | [diff] [blame] | 3952 | raw_spin_lock(&cfs_b->lock); |
Ben Segall | db06e78 | 2013-10-16 11:16:17 -0700 | [diff] [blame] | 3953 | if (runtime_refresh_within(cfs_b, min_bandwidth_expiration)) { |
| 3954 | raw_spin_unlock(&cfs_b->lock); |
| 3955 | return; |
| 3956 | } |
| 3957 | |
Ben Segall | c06f04c | 2014-06-20 15:21:20 -0700 | [diff] [blame] | 3958 | if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice) |
Paul Turner | d8b4986 | 2011-07-21 09:43:41 -0700 | [diff] [blame] | 3959 | runtime = cfs_b->runtime; |
Ben Segall | c06f04c | 2014-06-20 15:21:20 -0700 | [diff] [blame] | 3960 | |
Paul Turner | d8b4986 | 2011-07-21 09:43:41 -0700 | [diff] [blame] | 3961 | expires = cfs_b->runtime_expires; |
| 3962 | raw_spin_unlock(&cfs_b->lock); |
| 3963 | |
| 3964 | if (!runtime) |
| 3965 | return; |
| 3966 | |
| 3967 | runtime = distribute_cfs_runtime(cfs_b, runtime, expires); |
| 3968 | |
| 3969 | raw_spin_lock(&cfs_b->lock); |
| 3970 | if (expires == cfs_b->runtime_expires) |
Ben Segall | c06f04c | 2014-06-20 15:21:20 -0700 | [diff] [blame] | 3971 | cfs_b->runtime -= min(runtime, cfs_b->runtime); |
Paul Turner | d8b4986 | 2011-07-21 09:43:41 -0700 | [diff] [blame] | 3972 | raw_spin_unlock(&cfs_b->lock); |
| 3973 | } |
| 3974 | |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 3975 | /* |
| 3976 | * When a group wakes up we want to make sure that its quota is not already |
| 3977 | * expired/exceeded, otherwise it may be allowed to steal additional ticks of |
| 3978 | * runtime as update_curr() throttling can not not trigger until it's on-rq. |
| 3979 | */ |
| 3980 | static void check_enqueue_throttle(struct cfs_rq *cfs_rq) |
| 3981 | { |
Paul Turner | 56f570e | 2011-11-07 20:26:33 -0800 | [diff] [blame] | 3982 | if (!cfs_bandwidth_used()) |
| 3983 | return; |
| 3984 | |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 3985 | /* an active group must be handled by the update_curr()->put() path */ |
| 3986 | if (!cfs_rq->runtime_enabled || cfs_rq->curr) |
| 3987 | return; |
| 3988 | |
| 3989 | /* ensure the group is not already throttled */ |
| 3990 | if (cfs_rq_throttled(cfs_rq)) |
| 3991 | return; |
| 3992 | |
| 3993 | /* update runtime allocation */ |
| 3994 | account_cfs_rq_runtime(cfs_rq, 0); |
| 3995 | if (cfs_rq->runtime_remaining <= 0) |
| 3996 | throttle_cfs_rq(cfs_rq); |
| 3997 | } |
| 3998 | |
| 3999 | /* conditionally throttle active cfs_rq's from put_prev_entity() */ |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 4000 | static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq) |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 4001 | { |
Paul Turner | 56f570e | 2011-11-07 20:26:33 -0800 | [diff] [blame] | 4002 | if (!cfs_bandwidth_used()) |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 4003 | return false; |
Paul Turner | 56f570e | 2011-11-07 20:26:33 -0800 | [diff] [blame] | 4004 | |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 4005 | if (likely(!cfs_rq->runtime_enabled || cfs_rq->runtime_remaining > 0)) |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 4006 | return false; |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 4007 | |
| 4008 | /* |
| 4009 | * it's possible for a throttled entity to be forced into a running |
| 4010 | * state (e.g. set_curr_task), in this case we're finished. |
| 4011 | */ |
| 4012 | if (cfs_rq_throttled(cfs_rq)) |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 4013 | return true; |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 4014 | |
| 4015 | throttle_cfs_rq(cfs_rq); |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 4016 | return true; |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 4017 | } |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4018 | |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4019 | static enum hrtimer_restart sched_cfs_slack_timer(struct hrtimer *timer) |
| 4020 | { |
| 4021 | struct cfs_bandwidth *cfs_b = |
| 4022 | container_of(timer, struct cfs_bandwidth, slack_timer); |
Peter Zijlstra | 77a4d1a | 2015-04-15 11:41:57 +0200 | [diff] [blame] | 4023 | |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4024 | do_sched_cfs_slack_timer(cfs_b); |
| 4025 | |
| 4026 | return HRTIMER_NORESTART; |
| 4027 | } |
| 4028 | |
| 4029 | static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer) |
| 4030 | { |
| 4031 | struct cfs_bandwidth *cfs_b = |
| 4032 | container_of(timer, struct cfs_bandwidth, period_timer); |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4033 | int overrun; |
| 4034 | int idle = 0; |
| 4035 | |
Ben Segall | 51f2176 | 2014-05-19 15:49:45 -0700 | [diff] [blame] | 4036 | raw_spin_lock(&cfs_b->lock); |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4037 | for (;;) { |
Peter Zijlstra | 77a4d1a | 2015-04-15 11:41:57 +0200 | [diff] [blame] | 4038 | overrun = hrtimer_forward_now(timer, cfs_b->period); |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4039 | if (!overrun) |
| 4040 | break; |
| 4041 | |
| 4042 | idle = do_sched_cfs_period_timer(cfs_b, overrun); |
| 4043 | } |
Peter Zijlstra | 4cfafd3 | 2015-05-14 12:23:11 +0200 | [diff] [blame] | 4044 | if (idle) |
| 4045 | cfs_b->period_active = 0; |
Ben Segall | 51f2176 | 2014-05-19 15:49:45 -0700 | [diff] [blame] | 4046 | raw_spin_unlock(&cfs_b->lock); |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4047 | |
| 4048 | return idle ? HRTIMER_NORESTART : HRTIMER_RESTART; |
| 4049 | } |
| 4050 | |
| 4051 | void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) |
| 4052 | { |
| 4053 | raw_spin_lock_init(&cfs_b->lock); |
| 4054 | cfs_b->runtime = 0; |
| 4055 | cfs_b->quota = RUNTIME_INF; |
| 4056 | cfs_b->period = ns_to_ktime(default_cfs_period()); |
| 4057 | |
| 4058 | INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq); |
Peter Zijlstra | 4cfafd3 | 2015-05-14 12:23:11 +0200 | [diff] [blame] | 4059 | hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED); |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4060 | cfs_b->period_timer.function = sched_cfs_period_timer; |
| 4061 | hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
| 4062 | cfs_b->slack_timer.function = sched_cfs_slack_timer; |
| 4063 | } |
| 4064 | |
| 4065 | static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) |
| 4066 | { |
| 4067 | cfs_rq->runtime_enabled = 0; |
| 4068 | INIT_LIST_HEAD(&cfs_rq->throttled_list); |
| 4069 | } |
| 4070 | |
Peter Zijlstra | 77a4d1a | 2015-04-15 11:41:57 +0200 | [diff] [blame] | 4071 | void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b) |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4072 | { |
Peter Zijlstra | 4cfafd3 | 2015-05-14 12:23:11 +0200 | [diff] [blame] | 4073 | lockdep_assert_held(&cfs_b->lock); |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4074 | |
Peter Zijlstra | 4cfafd3 | 2015-05-14 12:23:11 +0200 | [diff] [blame] | 4075 | if (!cfs_b->period_active) { |
| 4076 | cfs_b->period_active = 1; |
| 4077 | hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period); |
| 4078 | hrtimer_start_expires(&cfs_b->period_timer, HRTIMER_MODE_ABS_PINNED); |
| 4079 | } |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4080 | } |
| 4081 | |
| 4082 | static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) |
| 4083 | { |
Tetsuo Handa | 7f1a169 | 2014-12-25 15:51:21 +0900 | [diff] [blame] | 4084 | /* init_cfs_bandwidth() was not called */ |
| 4085 | if (!cfs_b->throttled_cfs_rq.next) |
| 4086 | return; |
| 4087 | |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4088 | hrtimer_cancel(&cfs_b->period_timer); |
| 4089 | hrtimer_cancel(&cfs_b->slack_timer); |
| 4090 | } |
| 4091 | |
Kirill Tkhai | 0e59bda | 2014-06-25 12:19:42 +0400 | [diff] [blame] | 4092 | static void __maybe_unused update_runtime_enabled(struct rq *rq) |
| 4093 | { |
| 4094 | struct cfs_rq *cfs_rq; |
| 4095 | |
| 4096 | for_each_leaf_cfs_rq(rq, cfs_rq) { |
| 4097 | struct cfs_bandwidth *cfs_b = &cfs_rq->tg->cfs_bandwidth; |
| 4098 | |
| 4099 | raw_spin_lock(&cfs_b->lock); |
| 4100 | cfs_rq->runtime_enabled = cfs_b->quota != RUNTIME_INF; |
| 4101 | raw_spin_unlock(&cfs_b->lock); |
| 4102 | } |
| 4103 | } |
| 4104 | |
Arnd Bergmann | 38dc334 | 2013-01-25 14:14:22 +0000 | [diff] [blame] | 4105 | static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq) |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4106 | { |
| 4107 | struct cfs_rq *cfs_rq; |
| 4108 | |
| 4109 | for_each_leaf_cfs_rq(rq, cfs_rq) { |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4110 | if (!cfs_rq->runtime_enabled) |
| 4111 | continue; |
| 4112 | |
| 4113 | /* |
| 4114 | * clock_task is not advancing so we just need to make sure |
| 4115 | * there's some valid quota amount |
| 4116 | */ |
Ben Segall | 51f2176 | 2014-05-19 15:49:45 -0700 | [diff] [blame] | 4117 | cfs_rq->runtime_remaining = 1; |
Kirill Tkhai | 0e59bda | 2014-06-25 12:19:42 +0400 | [diff] [blame] | 4118 | /* |
| 4119 | * Offline rq is schedulable till cpu is completely disabled |
| 4120 | * in take_cpu_down(), so we prevent new cfs throttling here. |
| 4121 | */ |
| 4122 | cfs_rq->runtime_enabled = 0; |
| 4123 | |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4124 | if (cfs_rq_throttled(cfs_rq)) |
| 4125 | unthrottle_cfs_rq(cfs_rq); |
| 4126 | } |
| 4127 | } |
| 4128 | |
| 4129 | #else /* CONFIG_CFS_BANDWIDTH */ |
Paul Turner | f1b1728 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 4130 | static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq) |
| 4131 | { |
Frederic Weisbecker | 78becc2 | 2013-04-12 01:51:02 +0200 | [diff] [blame] | 4132 | return rq_clock_task(rq_of(cfs_rq)); |
Paul Turner | f1b1728 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 4133 | } |
| 4134 | |
Peter Zijlstra | 9dbdb15 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 4135 | static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) {} |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 4136 | static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq) { return false; } |
Paul Turner | d3d9dc3 | 2011-07-21 09:43:39 -0700 | [diff] [blame] | 4137 | static void check_enqueue_throttle(struct cfs_rq *cfs_rq) {} |
Peter Zijlstra | 6c16a6d | 2012-03-21 13:07:16 -0700 | [diff] [blame] | 4138 | static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) {} |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 4139 | |
| 4140 | static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq) |
| 4141 | { |
| 4142 | return 0; |
| 4143 | } |
Paul Turner | 64660c8 | 2011-07-21 09:43:36 -0700 | [diff] [blame] | 4144 | |
| 4145 | static inline int throttled_hierarchy(struct cfs_rq *cfs_rq) |
| 4146 | { |
| 4147 | return 0; |
| 4148 | } |
| 4149 | |
| 4150 | static inline int throttled_lb_pair(struct task_group *tg, |
| 4151 | int src_cpu, int dest_cpu) |
| 4152 | { |
| 4153 | return 0; |
| 4154 | } |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4155 | |
| 4156 | void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {} |
| 4157 | |
| 4158 | #ifdef CONFIG_FAIR_GROUP_SCHED |
| 4159 | static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) {} |
Paul Turner | ab84d31 | 2011-07-21 09:43:28 -0700 | [diff] [blame] | 4160 | #endif |
| 4161 | |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4162 | static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg) |
| 4163 | { |
| 4164 | return NULL; |
| 4165 | } |
| 4166 | static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {} |
Kirill Tkhai | 0e59bda | 2014-06-25 12:19:42 +0400 | [diff] [blame] | 4167 | static inline void update_runtime_enabled(struct rq *rq) {} |
Peter Boonstoppel | a4c96ae | 2012-08-09 15:34:47 -0700 | [diff] [blame] | 4168 | static inline void unthrottle_offline_cfs_rqs(struct rq *rq) {} |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4169 | |
| 4170 | #endif /* CONFIG_CFS_BANDWIDTH */ |
| 4171 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4172 | /************************************************** |
| 4173 | * CFS operations on tasks: |
| 4174 | */ |
| 4175 | |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 4176 | #ifdef CONFIG_SCHED_HRTICK |
| 4177 | static void hrtick_start_fair(struct rq *rq, struct task_struct *p) |
| 4178 | { |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 4179 | struct sched_entity *se = &p->se; |
| 4180 | struct cfs_rq *cfs_rq = cfs_rq_of(se); |
| 4181 | |
| 4182 | WARN_ON(task_rq(p) != rq); |
| 4183 | |
Mike Galbraith | b39e66e | 2011-11-22 15:20:07 +0100 | [diff] [blame] | 4184 | if (cfs_rq->nr_running > 1) { |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 4185 | u64 slice = sched_slice(cfs_rq, se); |
| 4186 | u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime; |
| 4187 | s64 delta = slice - ran; |
| 4188 | |
| 4189 | if (delta < 0) { |
| 4190 | if (rq->curr == p) |
Kirill Tkhai | 8875125 | 2014-06-29 00:03:57 +0400 | [diff] [blame] | 4191 | resched_curr(rq); |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 4192 | return; |
| 4193 | } |
Peter Zijlstra | 3165651 | 2008-07-18 18:01:23 +0200 | [diff] [blame] | 4194 | hrtick_start(rq, delta); |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 4195 | } |
| 4196 | } |
Peter Zijlstra | a4c2f00 | 2008-10-17 19:27:03 +0200 | [diff] [blame] | 4197 | |
| 4198 | /* |
| 4199 | * called from enqueue/dequeue and updates the hrtick when the |
| 4200 | * current task is from our class and nr_running is low enough |
| 4201 | * to matter. |
| 4202 | */ |
| 4203 | static void hrtick_update(struct rq *rq) |
| 4204 | { |
| 4205 | struct task_struct *curr = rq->curr; |
| 4206 | |
Mike Galbraith | b39e66e | 2011-11-22 15:20:07 +0100 | [diff] [blame] | 4207 | if (!hrtick_enabled(rq) || curr->sched_class != &fair_sched_class) |
Peter Zijlstra | a4c2f00 | 2008-10-17 19:27:03 +0200 | [diff] [blame] | 4208 | return; |
| 4209 | |
| 4210 | if (cfs_rq_of(&curr->se)->nr_running < sched_nr_latency) |
| 4211 | hrtick_start_fair(rq, curr); |
| 4212 | } |
Dhaval Giani | 55e12e5 | 2008-06-24 23:39:43 +0530 | [diff] [blame] | 4213 | #else /* !CONFIG_SCHED_HRTICK */ |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 4214 | static inline void |
| 4215 | hrtick_start_fair(struct rq *rq, struct task_struct *p) |
| 4216 | { |
| 4217 | } |
Peter Zijlstra | a4c2f00 | 2008-10-17 19:27:03 +0200 | [diff] [blame] | 4218 | |
| 4219 | static inline void hrtick_update(struct rq *rq) |
| 4220 | { |
| 4221 | } |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 4222 | #endif |
| 4223 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4224 | /* |
| 4225 | * The enqueue_task method is called before nr_running is |
| 4226 | * increased. Here we update the fair scheduling stats and |
| 4227 | * then put the task into the rbtree: |
| 4228 | */ |
Thomas Gleixner | ea87bb7 | 2010-01-20 20:58:57 +0000 | [diff] [blame] | 4229 | static void |
Peter Zijlstra | 371fd7e | 2010-03-24 16:38:48 +0100 | [diff] [blame] | 4230 | enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4231 | { |
| 4232 | struct cfs_rq *cfs_rq; |
Peter Zijlstra | 62fb185 | 2008-02-25 17:34:02 +0100 | [diff] [blame] | 4233 | struct sched_entity *se = &p->se; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4234 | |
| 4235 | for_each_sched_entity(se) { |
Peter Zijlstra | 62fb185 | 2008-02-25 17:34:02 +0100 | [diff] [blame] | 4236 | if (se->on_rq) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4237 | break; |
| 4238 | cfs_rq = cfs_rq_of(se); |
Peter Zijlstra | 88ec22d | 2009-12-16 18:04:41 +0100 | [diff] [blame] | 4239 | enqueue_entity(cfs_rq, se, flags); |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 4240 | |
| 4241 | /* |
| 4242 | * end evaluation on encountering a throttled cfs_rq |
| 4243 | * |
| 4244 | * note: in the case of encountering a throttled cfs_rq we will |
| 4245 | * post the final h_nr_running increment below. |
| 4246 | */ |
| 4247 | if (cfs_rq_throttled(cfs_rq)) |
| 4248 | break; |
Paul Turner | 953bfcd1 | 2011-07-21 09:43:27 -0700 | [diff] [blame] | 4249 | cfs_rq->h_nr_running++; |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 4250 | |
Peter Zijlstra | 88ec22d | 2009-12-16 18:04:41 +0100 | [diff] [blame] | 4251 | flags = ENQUEUE_WAKEUP; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4252 | } |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 4253 | |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 4254 | for_each_sched_entity(se) { |
Lin Ming | 0f31714 | 2011-07-22 09:14:31 +0800 | [diff] [blame] | 4255 | cfs_rq = cfs_rq_of(se); |
Paul Turner | 953bfcd1 | 2011-07-21 09:43:27 -0700 | [diff] [blame] | 4256 | cfs_rq->h_nr_running++; |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 4257 | |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 4258 | if (cfs_rq_throttled(cfs_rq)) |
| 4259 | break; |
| 4260 | |
Linus Torvalds | 17bc14b | 2012-12-14 07:20:43 -0800 | [diff] [blame] | 4261 | update_cfs_shares(cfs_rq); |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 4262 | update_entity_load_avg(se, 1); |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 4263 | } |
| 4264 | |
Ben Segall | 18bf280 | 2012-10-04 12:51:20 +0200 | [diff] [blame] | 4265 | if (!se) { |
| 4266 | update_rq_runnable_avg(rq, rq->nr_running); |
Kirill Tkhai | 7246544 | 2014-05-09 03:00:14 +0400 | [diff] [blame] | 4267 | add_nr_running(rq, 1); |
Ben Segall | 18bf280 | 2012-10-04 12:51:20 +0200 | [diff] [blame] | 4268 | } |
Peter Zijlstra | a4c2f00 | 2008-10-17 19:27:03 +0200 | [diff] [blame] | 4269 | hrtick_update(rq); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4270 | } |
| 4271 | |
Venkatesh Pallipadi | 2f36825 | 2011-04-14 10:30:53 -0700 | [diff] [blame] | 4272 | static void set_next_buddy(struct sched_entity *se); |
| 4273 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4274 | /* |
| 4275 | * The dequeue_task method is called before nr_running is |
| 4276 | * decreased. We remove the task from the rbtree and |
| 4277 | * update the fair scheduling stats: |
| 4278 | */ |
Peter Zijlstra | 371fd7e | 2010-03-24 16:38:48 +0100 | [diff] [blame] | 4279 | static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4280 | { |
| 4281 | struct cfs_rq *cfs_rq; |
Peter Zijlstra | 62fb185 | 2008-02-25 17:34:02 +0100 | [diff] [blame] | 4282 | struct sched_entity *se = &p->se; |
Venkatesh Pallipadi | 2f36825 | 2011-04-14 10:30:53 -0700 | [diff] [blame] | 4283 | int task_sleep = flags & DEQUEUE_SLEEP; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4284 | |
| 4285 | for_each_sched_entity(se) { |
| 4286 | cfs_rq = cfs_rq_of(se); |
Peter Zijlstra | 371fd7e | 2010-03-24 16:38:48 +0100 | [diff] [blame] | 4287 | dequeue_entity(cfs_rq, se, flags); |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 4288 | |
| 4289 | /* |
| 4290 | * end evaluation on encountering a throttled cfs_rq |
| 4291 | * |
| 4292 | * note: in the case of encountering a throttled cfs_rq we will |
| 4293 | * post the final h_nr_running decrement below. |
| 4294 | */ |
| 4295 | if (cfs_rq_throttled(cfs_rq)) |
| 4296 | break; |
Paul Turner | 953bfcd1 | 2011-07-21 09:43:27 -0700 | [diff] [blame] | 4297 | cfs_rq->h_nr_running--; |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 4298 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4299 | /* Don't dequeue parent if it has other entities besides us */ |
Venkatesh Pallipadi | 2f36825 | 2011-04-14 10:30:53 -0700 | [diff] [blame] | 4300 | if (cfs_rq->load.weight) { |
| 4301 | /* |
| 4302 | * Bias pick_next to pick a task from this cfs_rq, as |
| 4303 | * p is sleeping when it is within its sched_slice. |
| 4304 | */ |
| 4305 | if (task_sleep && parent_entity(se)) |
| 4306 | set_next_buddy(parent_entity(se)); |
Paul Turner | 9598c82 | 2011-07-06 22:30:37 -0700 | [diff] [blame] | 4307 | |
| 4308 | /* avoid re-evaluating load for this entity */ |
| 4309 | se = parent_entity(se); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4310 | break; |
Venkatesh Pallipadi | 2f36825 | 2011-04-14 10:30:53 -0700 | [diff] [blame] | 4311 | } |
Peter Zijlstra | 371fd7e | 2010-03-24 16:38:48 +0100 | [diff] [blame] | 4312 | flags |= DEQUEUE_SLEEP; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4313 | } |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 4314 | |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 4315 | for_each_sched_entity(se) { |
Lin Ming | 0f31714 | 2011-07-22 09:14:31 +0800 | [diff] [blame] | 4316 | cfs_rq = cfs_rq_of(se); |
Paul Turner | 953bfcd1 | 2011-07-21 09:43:27 -0700 | [diff] [blame] | 4317 | cfs_rq->h_nr_running--; |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 4318 | |
Paul Turner | 85dac90 | 2011-07-21 09:43:33 -0700 | [diff] [blame] | 4319 | if (cfs_rq_throttled(cfs_rq)) |
| 4320 | break; |
| 4321 | |
Linus Torvalds | 17bc14b | 2012-12-14 07:20:43 -0800 | [diff] [blame] | 4322 | update_cfs_shares(cfs_rq); |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 4323 | update_entity_load_avg(se, 1); |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 4324 | } |
| 4325 | |
Ben Segall | 18bf280 | 2012-10-04 12:51:20 +0200 | [diff] [blame] | 4326 | if (!se) { |
Kirill Tkhai | 7246544 | 2014-05-09 03:00:14 +0400 | [diff] [blame] | 4327 | sub_nr_running(rq, 1); |
Ben Segall | 18bf280 | 2012-10-04 12:51:20 +0200 | [diff] [blame] | 4328 | update_rq_runnable_avg(rq, 1); |
| 4329 | } |
Peter Zijlstra | a4c2f00 | 2008-10-17 19:27:03 +0200 | [diff] [blame] | 4330 | hrtick_update(rq); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4331 | } |
| 4332 | |
Gregory Haskins | e7693a3 | 2008-01-25 21:08:09 +0100 | [diff] [blame] | 4333 | #ifdef CONFIG_SMP |
Peter Zijlstra | 3289bdb | 2015-04-14 13:19:42 +0200 | [diff] [blame] | 4334 | |
| 4335 | /* |
| 4336 | * per rq 'load' arrray crap; XXX kill this. |
| 4337 | */ |
| 4338 | |
| 4339 | /* |
| 4340 | * The exact cpuload at various idx values, calculated at every tick would be |
| 4341 | * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load |
| 4342 | * |
| 4343 | * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called |
| 4344 | * on nth tick when cpu may be busy, then we have: |
| 4345 | * load = ((2^idx - 1) / 2^idx)^(n-1) * load |
| 4346 | * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load |
| 4347 | * |
| 4348 | * decay_load_missed() below does efficient calculation of |
| 4349 | * load = ((2^idx - 1) / 2^idx)^(n-1) * load |
| 4350 | * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load |
| 4351 | * |
| 4352 | * The calculation is approximated on a 128 point scale. |
| 4353 | * degrade_zero_ticks is the number of ticks after which load at any |
| 4354 | * particular idx is approximated to be zero. |
| 4355 | * degrade_factor is a precomputed table, a row for each load idx. |
| 4356 | * Each column corresponds to degradation factor for a power of two ticks, |
| 4357 | * based on 128 point scale. |
| 4358 | * Example: |
| 4359 | * row 2, col 3 (=12) says that the degradation at load idx 2 after |
| 4360 | * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8). |
| 4361 | * |
| 4362 | * With this power of 2 load factors, we can degrade the load n times |
| 4363 | * by looking at 1 bits in n and doing as many mult/shift instead of |
| 4364 | * n mult/shifts needed by the exact degradation. |
| 4365 | */ |
| 4366 | #define DEGRADE_SHIFT 7 |
| 4367 | static const unsigned char |
| 4368 | degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128}; |
| 4369 | static const unsigned char |
| 4370 | degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = { |
| 4371 | {0, 0, 0, 0, 0, 0, 0, 0}, |
| 4372 | {64, 32, 8, 0, 0, 0, 0, 0}, |
| 4373 | {96, 72, 40, 12, 1, 0, 0}, |
| 4374 | {112, 98, 75, 43, 15, 1, 0}, |
| 4375 | {120, 112, 98, 76, 45, 16, 2} }; |
| 4376 | |
| 4377 | /* |
| 4378 | * Update cpu_load for any missed ticks, due to tickless idle. The backlog |
| 4379 | * would be when CPU is idle and so we just decay the old load without |
| 4380 | * adding any new load. |
| 4381 | */ |
| 4382 | static unsigned long |
| 4383 | decay_load_missed(unsigned long load, unsigned long missed_updates, int idx) |
| 4384 | { |
| 4385 | int j = 0; |
| 4386 | |
| 4387 | if (!missed_updates) |
| 4388 | return load; |
| 4389 | |
| 4390 | if (missed_updates >= degrade_zero_ticks[idx]) |
| 4391 | return 0; |
| 4392 | |
| 4393 | if (idx == 1) |
| 4394 | return load >> missed_updates; |
| 4395 | |
| 4396 | while (missed_updates) { |
| 4397 | if (missed_updates % 2) |
| 4398 | load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT; |
| 4399 | |
| 4400 | missed_updates >>= 1; |
| 4401 | j++; |
| 4402 | } |
| 4403 | return load; |
| 4404 | } |
| 4405 | |
| 4406 | /* |
| 4407 | * Update rq->cpu_load[] statistics. This function is usually called every |
| 4408 | * scheduler tick (TICK_NSEC). With tickless idle this will not be called |
| 4409 | * every tick. We fix it up based on jiffies. |
| 4410 | */ |
| 4411 | static void __update_cpu_load(struct rq *this_rq, unsigned long this_load, |
| 4412 | unsigned long pending_updates) |
| 4413 | { |
| 4414 | int i, scale; |
| 4415 | |
| 4416 | this_rq->nr_load_updates++; |
| 4417 | |
| 4418 | /* Update our load: */ |
| 4419 | this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */ |
| 4420 | for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { |
| 4421 | unsigned long old_load, new_load; |
| 4422 | |
| 4423 | /* scale is effectively 1 << i now, and >> i divides by scale */ |
| 4424 | |
| 4425 | old_load = this_rq->cpu_load[i]; |
| 4426 | old_load = decay_load_missed(old_load, pending_updates - 1, i); |
| 4427 | new_load = this_load; |
| 4428 | /* |
| 4429 | * Round up the averaging division if load is increasing. This |
| 4430 | * prevents us from getting stuck on 9 if the load is 10, for |
| 4431 | * example. |
| 4432 | */ |
| 4433 | if (new_load > old_load) |
| 4434 | new_load += scale - 1; |
| 4435 | |
| 4436 | this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i; |
| 4437 | } |
| 4438 | |
| 4439 | sched_avg_update(this_rq); |
| 4440 | } |
| 4441 | |
| 4442 | #ifdef CONFIG_NO_HZ_COMMON |
| 4443 | /* |
| 4444 | * There is no sane way to deal with nohz on smp when using jiffies because the |
| 4445 | * cpu doing the jiffies update might drift wrt the cpu doing the jiffy reading |
| 4446 | * causing off-by-one errors in observed deltas; {0,2} instead of {1,1}. |
| 4447 | * |
| 4448 | * Therefore we cannot use the delta approach from the regular tick since that |
| 4449 | * would seriously skew the load calculation. However we'll make do for those |
| 4450 | * updates happening while idle (nohz_idle_balance) or coming out of idle |
| 4451 | * (tick_nohz_idle_exit). |
| 4452 | * |
| 4453 | * This means we might still be one tick off for nohz periods. |
| 4454 | */ |
| 4455 | |
| 4456 | /* |
| 4457 | * Called from nohz_idle_balance() to update the load ratings before doing the |
| 4458 | * idle balance. |
| 4459 | */ |
| 4460 | static void update_idle_cpu_load(struct rq *this_rq) |
| 4461 | { |
Jason Low | 316c1608d | 2015-04-28 13:00:20 -0700 | [diff] [blame] | 4462 | unsigned long curr_jiffies = READ_ONCE(jiffies); |
Peter Zijlstra | 3289bdb | 2015-04-14 13:19:42 +0200 | [diff] [blame] | 4463 | unsigned long load = this_rq->cfs.runnable_load_avg; |
| 4464 | unsigned long pending_updates; |
| 4465 | |
| 4466 | /* |
| 4467 | * bail if there's load or we're actually up-to-date. |
| 4468 | */ |
| 4469 | if (load || curr_jiffies == this_rq->last_load_update_tick) |
| 4470 | return; |
| 4471 | |
| 4472 | pending_updates = curr_jiffies - this_rq->last_load_update_tick; |
| 4473 | this_rq->last_load_update_tick = curr_jiffies; |
| 4474 | |
| 4475 | __update_cpu_load(this_rq, load, pending_updates); |
| 4476 | } |
| 4477 | |
| 4478 | /* |
| 4479 | * Called from tick_nohz_idle_exit() -- try and fix up the ticks we missed. |
| 4480 | */ |
| 4481 | void update_cpu_load_nohz(void) |
| 4482 | { |
| 4483 | struct rq *this_rq = this_rq(); |
Jason Low | 316c1608d | 2015-04-28 13:00:20 -0700 | [diff] [blame] | 4484 | unsigned long curr_jiffies = READ_ONCE(jiffies); |
Peter Zijlstra | 3289bdb | 2015-04-14 13:19:42 +0200 | [diff] [blame] | 4485 | unsigned long pending_updates; |
| 4486 | |
| 4487 | if (curr_jiffies == this_rq->last_load_update_tick) |
| 4488 | return; |
| 4489 | |
| 4490 | raw_spin_lock(&this_rq->lock); |
| 4491 | pending_updates = curr_jiffies - this_rq->last_load_update_tick; |
| 4492 | if (pending_updates) { |
| 4493 | this_rq->last_load_update_tick = curr_jiffies; |
| 4494 | /* |
| 4495 | * We were idle, this means load 0, the current load might be |
| 4496 | * !0 due to remote wakeups and the sort. |
| 4497 | */ |
| 4498 | __update_cpu_load(this_rq, 0, pending_updates); |
| 4499 | } |
| 4500 | raw_spin_unlock(&this_rq->lock); |
| 4501 | } |
| 4502 | #endif /* CONFIG_NO_HZ */ |
| 4503 | |
| 4504 | /* |
| 4505 | * Called from scheduler_tick() |
| 4506 | */ |
| 4507 | void update_cpu_load_active(struct rq *this_rq) |
| 4508 | { |
| 4509 | unsigned long load = this_rq->cfs.runnable_load_avg; |
| 4510 | /* |
| 4511 | * See the mess around update_idle_cpu_load() / update_cpu_load_nohz(). |
| 4512 | */ |
| 4513 | this_rq->last_load_update_tick = jiffies; |
| 4514 | __update_cpu_load(this_rq, load, 1); |
| 4515 | } |
| 4516 | |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4517 | /* Used instead of source_load when we know the type == 0 */ |
| 4518 | static unsigned long weighted_cpuload(const int cpu) |
| 4519 | { |
Alex Shi | b92486c | 2013-06-20 10:18:50 +0800 | [diff] [blame] | 4520 | return cpu_rq(cpu)->cfs.runnable_load_avg; |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4521 | } |
| 4522 | |
| 4523 | /* |
| 4524 | * Return a low guess at the load of a migration-source cpu weighted |
| 4525 | * according to the scheduling class and "nice" value. |
| 4526 | * |
| 4527 | * We want to under-estimate the load of migration sources, to |
| 4528 | * balance conservatively. |
| 4529 | */ |
| 4530 | static unsigned long source_load(int cpu, int type) |
| 4531 | { |
| 4532 | struct rq *rq = cpu_rq(cpu); |
| 4533 | unsigned long total = weighted_cpuload(cpu); |
| 4534 | |
| 4535 | if (type == 0 || !sched_feat(LB_BIAS)) |
| 4536 | return total; |
| 4537 | |
| 4538 | return min(rq->cpu_load[type-1], total); |
| 4539 | } |
| 4540 | |
| 4541 | /* |
| 4542 | * Return a high guess at the load of a migration-target cpu weighted |
| 4543 | * according to the scheduling class and "nice" value. |
| 4544 | */ |
| 4545 | static unsigned long target_load(int cpu, int type) |
| 4546 | { |
| 4547 | struct rq *rq = cpu_rq(cpu); |
| 4548 | unsigned long total = weighted_cpuload(cpu); |
| 4549 | |
| 4550 | if (type == 0 || !sched_feat(LB_BIAS)) |
| 4551 | return total; |
| 4552 | |
| 4553 | return max(rq->cpu_load[type-1], total); |
| 4554 | } |
| 4555 | |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 4556 | static unsigned long capacity_of(int cpu) |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4557 | { |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 4558 | return cpu_rq(cpu)->cpu_capacity; |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4559 | } |
| 4560 | |
Vincent Guittot | ca6d75e | 2015-02-27 16:54:09 +0100 | [diff] [blame] | 4561 | static unsigned long capacity_orig_of(int cpu) |
| 4562 | { |
| 4563 | return cpu_rq(cpu)->cpu_capacity_orig; |
| 4564 | } |
| 4565 | |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4566 | static unsigned long cpu_avg_load_per_task(int cpu) |
| 4567 | { |
| 4568 | struct rq *rq = cpu_rq(cpu); |
Jason Low | 316c1608d | 2015-04-28 13:00:20 -0700 | [diff] [blame] | 4569 | unsigned long nr_running = READ_ONCE(rq->cfs.h_nr_running); |
Alex Shi | b92486c | 2013-06-20 10:18:50 +0800 | [diff] [blame] | 4570 | unsigned long load_avg = rq->cfs.runnable_load_avg; |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4571 | |
| 4572 | if (nr_running) |
Alex Shi | b92486c | 2013-06-20 10:18:50 +0800 | [diff] [blame] | 4573 | return load_avg / nr_running; |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 4574 | |
| 4575 | return 0; |
| 4576 | } |
| 4577 | |
Michael Wang | 6247041 | 2013-07-04 12:55:51 +0800 | [diff] [blame] | 4578 | static void record_wakee(struct task_struct *p) |
| 4579 | { |
| 4580 | /* |
| 4581 | * Rough decay (wiping) for cost saving, don't worry |
| 4582 | * about the boundary, really active task won't care |
| 4583 | * about the loss. |
| 4584 | */ |
Manuel Schölling | 2538d96 | 2014-05-22 19:45:23 +0200 | [diff] [blame] | 4585 | if (time_after(jiffies, current->wakee_flip_decay_ts + HZ)) { |
Rik van Riel | 096aa33 | 2014-05-16 00:13:32 -0400 | [diff] [blame] | 4586 | current->wakee_flips >>= 1; |
Michael Wang | 6247041 | 2013-07-04 12:55:51 +0800 | [diff] [blame] | 4587 | current->wakee_flip_decay_ts = jiffies; |
| 4588 | } |
| 4589 | |
| 4590 | if (current->last_wakee != p) { |
| 4591 | current->last_wakee = p; |
| 4592 | current->wakee_flips++; |
| 4593 | } |
| 4594 | } |
Ingo Molnar | 098fb9d | 2008-03-16 20:36:10 +0100 | [diff] [blame] | 4595 | |
Peter Zijlstra | 74f8e4b | 2011-04-05 17:23:47 +0200 | [diff] [blame] | 4596 | static void task_waking_fair(struct task_struct *p) |
Peter Zijlstra | 88ec22d | 2009-12-16 18:04:41 +0100 | [diff] [blame] | 4597 | { |
| 4598 | struct sched_entity *se = &p->se; |
| 4599 | struct cfs_rq *cfs_rq = cfs_rq_of(se); |
Peter Zijlstra | 3fe1698 | 2011-04-05 17:23:48 +0200 | [diff] [blame] | 4600 | u64 min_vruntime; |
Peter Zijlstra | 88ec22d | 2009-12-16 18:04:41 +0100 | [diff] [blame] | 4601 | |
Peter Zijlstra | 3fe1698 | 2011-04-05 17:23:48 +0200 | [diff] [blame] | 4602 | #ifndef CONFIG_64BIT |
| 4603 | u64 min_vruntime_copy; |
Peter Zijlstra | 74f8e4b | 2011-04-05 17:23:47 +0200 | [diff] [blame] | 4604 | |
Peter Zijlstra | 3fe1698 | 2011-04-05 17:23:48 +0200 | [diff] [blame] | 4605 | do { |
| 4606 | min_vruntime_copy = cfs_rq->min_vruntime_copy; |
| 4607 | smp_rmb(); |
| 4608 | min_vruntime = cfs_rq->min_vruntime; |
| 4609 | } while (min_vruntime != min_vruntime_copy); |
| 4610 | #else |
| 4611 | min_vruntime = cfs_rq->min_vruntime; |
| 4612 | #endif |
| 4613 | |
| 4614 | se->vruntime -= min_vruntime; |
Michael Wang | 6247041 | 2013-07-04 12:55:51 +0800 | [diff] [blame] | 4615 | record_wakee(p); |
Peter Zijlstra | 88ec22d | 2009-12-16 18:04:41 +0100 | [diff] [blame] | 4616 | } |
| 4617 | |
Peter Zijlstra | bb3469a | 2008-06-27 13:41:27 +0200 | [diff] [blame] | 4618 | #ifdef CONFIG_FAIR_GROUP_SCHED |
Peter Zijlstra | f5bfb7d | 2008-06-27 13:41:39 +0200 | [diff] [blame] | 4619 | /* |
| 4620 | * effective_load() calculates the load change as seen from the root_task_group |
| 4621 | * |
| 4622 | * Adding load to a group doesn't make a group heavier, but can cause movement |
| 4623 | * of group shares between cpus. Assuming the shares were perfectly aligned one |
| 4624 | * can calculate the shift in shares. |
Peter Zijlstra | cf5f0ac | 2011-10-13 16:52:28 +0200 | [diff] [blame] | 4625 | * |
| 4626 | * Calculate the effective load difference if @wl is added (subtracted) to @tg |
| 4627 | * on this @cpu and results in a total addition (subtraction) of @wg to the |
| 4628 | * total group weight. |
| 4629 | * |
| 4630 | * Given a runqueue weight distribution (rw_i) we can compute a shares |
| 4631 | * distribution (s_i) using: |
| 4632 | * |
| 4633 | * s_i = rw_i / \Sum rw_j (1) |
| 4634 | * |
| 4635 | * Suppose we have 4 CPUs and our @tg is a direct child of the root group and |
| 4636 | * has 7 equal weight tasks, distributed as below (rw_i), with the resulting |
| 4637 | * shares distribution (s_i): |
| 4638 | * |
| 4639 | * rw_i = { 2, 4, 1, 0 } |
| 4640 | * s_i = { 2/7, 4/7, 1/7, 0 } |
| 4641 | * |
| 4642 | * As per wake_affine() we're interested in the load of two CPUs (the CPU the |
| 4643 | * task used to run on and the CPU the waker is running on), we need to |
| 4644 | * compute the effect of waking a task on either CPU and, in case of a sync |
| 4645 | * wakeup, compute the effect of the current task going to sleep. |
| 4646 | * |
| 4647 | * So for a change of @wl to the local @cpu with an overall group weight change |
| 4648 | * of @wl we can compute the new shares distribution (s'_i) using: |
| 4649 | * |
| 4650 | * s'_i = (rw_i + @wl) / (@wg + \Sum rw_j) (2) |
| 4651 | * |
| 4652 | * Suppose we're interested in CPUs 0 and 1, and want to compute the load |
| 4653 | * differences in waking a task to CPU 0. The additional task changes the |
| 4654 | * weight and shares distributions like: |
| 4655 | * |
| 4656 | * rw'_i = { 3, 4, 1, 0 } |
| 4657 | * s'_i = { 3/8, 4/8, 1/8, 0 } |
| 4658 | * |
| 4659 | * We can then compute the difference in effective weight by using: |
| 4660 | * |
| 4661 | * dw_i = S * (s'_i - s_i) (3) |
| 4662 | * |
| 4663 | * Where 'S' is the group weight as seen by its parent. |
| 4664 | * |
| 4665 | * Therefore the effective change in loads on CPU 0 would be 5/56 (3/8 - 2/7) |
| 4666 | * times the weight of the group. The effect on CPU 1 would be -4/56 (4/8 - |
| 4667 | * 4/7) times the weight of the group. |
Peter Zijlstra | f5bfb7d | 2008-06-27 13:41:39 +0200 | [diff] [blame] | 4668 | */ |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 4669 | static long effective_load(struct task_group *tg, int cpu, long wl, long wg) |
Peter Zijlstra | bb3469a | 2008-06-27 13:41:27 +0200 | [diff] [blame] | 4670 | { |
Peter Zijlstra | 4be9daa | 2008-06-27 13:41:30 +0200 | [diff] [blame] | 4671 | struct sched_entity *se = tg->se[cpu]; |
Peter Zijlstra | f1d239f | 2008-06-27 13:41:38 +0200 | [diff] [blame] | 4672 | |
Rik van Riel | 9722c2d | 2014-01-06 11:39:12 +0000 | [diff] [blame] | 4673 | if (!tg->parent) /* the trivial, non-cgroup case */ |
Peter Zijlstra | f1d239f | 2008-06-27 13:41:38 +0200 | [diff] [blame] | 4674 | return wl; |
| 4675 | |
Peter Zijlstra | 4be9daa | 2008-06-27 13:41:30 +0200 | [diff] [blame] | 4676 | for_each_sched_entity(se) { |
Peter Zijlstra | cf5f0ac | 2011-10-13 16:52:28 +0200 | [diff] [blame] | 4677 | long w, W; |
Peter Zijlstra | bb3469a | 2008-06-27 13:41:27 +0200 | [diff] [blame] | 4678 | |
Paul Turner | 977dda7 | 2011-01-14 17:57:50 -0800 | [diff] [blame] | 4679 | tg = se->my_q->tg; |
Peter Zijlstra | 4be9daa | 2008-06-27 13:41:30 +0200 | [diff] [blame] | 4680 | |
Peter Zijlstra | cf5f0ac | 2011-10-13 16:52:28 +0200 | [diff] [blame] | 4681 | /* |
| 4682 | * W = @wg + \Sum rw_j |
| 4683 | */ |
| 4684 | W = wg + calc_tg_weight(tg, se->my_q); |
Peter Zijlstra | 4be9daa | 2008-06-27 13:41:30 +0200 | [diff] [blame] | 4685 | |
Peter Zijlstra | cf5f0ac | 2011-10-13 16:52:28 +0200 | [diff] [blame] | 4686 | /* |
| 4687 | * w = rw_i + @wl |
| 4688 | */ |
| 4689 | w = se->my_q->load.weight + wl; |
Peter Zijlstra | 940959e | 2008-09-23 15:33:42 +0200 | [diff] [blame] | 4690 | |
Peter Zijlstra | cf5f0ac | 2011-10-13 16:52:28 +0200 | [diff] [blame] | 4691 | /* |
| 4692 | * wl = S * s'_i; see (2) |
| 4693 | */ |
| 4694 | if (W > 0 && w < W) |
Yuyang Du | 32a8df4 | 2014-12-19 08:29:56 +0800 | [diff] [blame] | 4695 | wl = (w * (long)tg->shares) / W; |
Paul Turner | 977dda7 | 2011-01-14 17:57:50 -0800 | [diff] [blame] | 4696 | else |
| 4697 | wl = tg->shares; |
Peter Zijlstra | 940959e | 2008-09-23 15:33:42 +0200 | [diff] [blame] | 4698 | |
Peter Zijlstra | cf5f0ac | 2011-10-13 16:52:28 +0200 | [diff] [blame] | 4699 | /* |
| 4700 | * Per the above, wl is the new se->load.weight value; since |
| 4701 | * those are clipped to [MIN_SHARES, ...) do so now. See |
| 4702 | * calc_cfs_shares(). |
| 4703 | */ |
Paul Turner | 977dda7 | 2011-01-14 17:57:50 -0800 | [diff] [blame] | 4704 | if (wl < MIN_SHARES) |
| 4705 | wl = MIN_SHARES; |
Peter Zijlstra | cf5f0ac | 2011-10-13 16:52:28 +0200 | [diff] [blame] | 4706 | |
| 4707 | /* |
| 4708 | * wl = dw_i = S * (s'_i - s_i); see (3) |
| 4709 | */ |
Paul Turner | 977dda7 | 2011-01-14 17:57:50 -0800 | [diff] [blame] | 4710 | wl -= se->load.weight; |
Peter Zijlstra | cf5f0ac | 2011-10-13 16:52:28 +0200 | [diff] [blame] | 4711 | |
| 4712 | /* |
| 4713 | * Recursively apply this logic to all parent groups to compute |
| 4714 | * the final effective load change on the root group. Since |
| 4715 | * only the @tg group gets extra weight, all parent groups can |
| 4716 | * only redistribute existing shares. @wl is the shift in shares |
| 4717 | * resulting from this level per the above. |
| 4718 | */ |
Peter Zijlstra | 4be9daa | 2008-06-27 13:41:30 +0200 | [diff] [blame] | 4719 | wg = 0; |
Peter Zijlstra | 4be9daa | 2008-06-27 13:41:30 +0200 | [diff] [blame] | 4720 | } |
| 4721 | |
| 4722 | return wl; |
Peter Zijlstra | bb3469a | 2008-06-27 13:41:27 +0200 | [diff] [blame] | 4723 | } |
| 4724 | #else |
Peter Zijlstra | 4be9daa | 2008-06-27 13:41:30 +0200 | [diff] [blame] | 4725 | |
Mel Gorman | 58d081b | 2013-10-07 11:29:10 +0100 | [diff] [blame] | 4726 | static long effective_load(struct task_group *tg, int cpu, long wl, long wg) |
Peter Zijlstra | 4be9daa | 2008-06-27 13:41:30 +0200 | [diff] [blame] | 4727 | { |
Peter Zijlstra | 8337826 | 2008-06-27 13:41:37 +0200 | [diff] [blame] | 4728 | return wl; |
Peter Zijlstra | bb3469a | 2008-06-27 13:41:27 +0200 | [diff] [blame] | 4729 | } |
Peter Zijlstra | 4be9daa | 2008-06-27 13:41:30 +0200 | [diff] [blame] | 4730 | |
Peter Zijlstra | bb3469a | 2008-06-27 13:41:27 +0200 | [diff] [blame] | 4731 | #endif |
| 4732 | |
Michael Wang | 6247041 | 2013-07-04 12:55:51 +0800 | [diff] [blame] | 4733 | static int wake_wide(struct task_struct *p) |
| 4734 | { |
Peter Zijlstra | 7d9ffa8 | 2013-07-04 12:56:46 +0800 | [diff] [blame] | 4735 | int factor = this_cpu_read(sd_llc_size); |
Michael Wang | 6247041 | 2013-07-04 12:55:51 +0800 | [diff] [blame] | 4736 | |
| 4737 | /* |
| 4738 | * Yeah, it's the switching-frequency, could means many wakee or |
| 4739 | * rapidly switch, use factor here will just help to automatically |
| 4740 | * adjust the loose-degree, so bigger node will lead to more pull. |
| 4741 | */ |
| 4742 | if (p->wakee_flips > factor) { |
| 4743 | /* |
| 4744 | * wakee is somewhat hot, it needs certain amount of cpu |
| 4745 | * resource, so if waker is far more hot, prefer to leave |
| 4746 | * it alone. |
| 4747 | */ |
| 4748 | if (current->wakee_flips > (factor * p->wakee_flips)) |
| 4749 | return 1; |
| 4750 | } |
| 4751 | |
| 4752 | return 0; |
| 4753 | } |
| 4754 | |
Peter Zijlstra | c88d591 | 2009-09-10 13:50:02 +0200 | [diff] [blame] | 4755 | static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) |
Ingo Molnar | 098fb9d | 2008-03-16 20:36:10 +0100 | [diff] [blame] | 4756 | { |
Paul Turner | e37b6a7 | 2011-01-21 20:44:59 -0800 | [diff] [blame] | 4757 | s64 this_load, load; |
Vincent Guittot | bd61c98 | 2014-08-26 13:06:50 +0200 | [diff] [blame] | 4758 | s64 this_eff_load, prev_eff_load; |
Peter Zijlstra | c88d591 | 2009-09-10 13:50:02 +0200 | [diff] [blame] | 4759 | int idx, this_cpu, prev_cpu; |
Peter Zijlstra | c88d591 | 2009-09-10 13:50:02 +0200 | [diff] [blame] | 4760 | struct task_group *tg; |
Peter Zijlstra | 8337826 | 2008-06-27 13:41:37 +0200 | [diff] [blame] | 4761 | unsigned long weight; |
Mike Galbraith | b3137bc | 2008-05-29 11:11:41 +0200 | [diff] [blame] | 4762 | int balanced; |
Ingo Molnar | 098fb9d | 2008-03-16 20:36:10 +0100 | [diff] [blame] | 4763 | |
Michael Wang | 6247041 | 2013-07-04 12:55:51 +0800 | [diff] [blame] | 4764 | /* |
| 4765 | * If we wake multiple tasks be careful to not bounce |
| 4766 | * ourselves around too much. |
| 4767 | */ |
| 4768 | if (wake_wide(p)) |
| 4769 | return 0; |
| 4770 | |
Peter Zijlstra | c88d591 | 2009-09-10 13:50:02 +0200 | [diff] [blame] | 4771 | idx = sd->wake_idx; |
| 4772 | this_cpu = smp_processor_id(); |
| 4773 | prev_cpu = task_cpu(p); |
| 4774 | load = source_load(prev_cpu, idx); |
| 4775 | this_load = target_load(this_cpu, idx); |
Ingo Molnar | 098fb9d | 2008-03-16 20:36:10 +0100 | [diff] [blame] | 4776 | |
| 4777 | /* |
Ingo Molnar | 098fb9d | 2008-03-16 20:36:10 +0100 | [diff] [blame] | 4778 | * If sync wakeup then subtract the (maximum possible) |
| 4779 | * effect of the currently running task from the load |
| 4780 | * of the current CPU: |
| 4781 | */ |
Peter Zijlstra | 8337826 | 2008-06-27 13:41:37 +0200 | [diff] [blame] | 4782 | if (sync) { |
| 4783 | tg = task_group(current); |
| 4784 | weight = current->se.load.weight; |
Ingo Molnar | 098fb9d | 2008-03-16 20:36:10 +0100 | [diff] [blame] | 4785 | |
Peter Zijlstra | c88d591 | 2009-09-10 13:50:02 +0200 | [diff] [blame] | 4786 | this_load += effective_load(tg, this_cpu, -weight, -weight); |
Peter Zijlstra | 8337826 | 2008-06-27 13:41:37 +0200 | [diff] [blame] | 4787 | load += effective_load(tg, prev_cpu, 0, -weight); |
| 4788 | } |
| 4789 | |
| 4790 | tg = task_group(p); |
| 4791 | weight = p->se.load.weight; |
| 4792 | |
Peter Zijlstra | 71a29aa | 2009-09-07 18:28:05 +0200 | [diff] [blame] | 4793 | /* |
| 4794 | * In low-load situations, where prev_cpu is idle and this_cpu is idle |
Peter Zijlstra | c88d591 | 2009-09-10 13:50:02 +0200 | [diff] [blame] | 4795 | * due to the sync cause above having dropped this_load to 0, we'll |
| 4796 | * always have an imbalance, but there's really nothing you can do |
| 4797 | * about that, so that's good too. |
Peter Zijlstra | 71a29aa | 2009-09-07 18:28:05 +0200 | [diff] [blame] | 4798 | * |
| 4799 | * Otherwise check if either cpus are near enough in load to allow this |
| 4800 | * task to be woken on this_cpu. |
| 4801 | */ |
Vincent Guittot | bd61c98 | 2014-08-26 13:06:50 +0200 | [diff] [blame] | 4802 | this_eff_load = 100; |
| 4803 | this_eff_load *= capacity_of(prev_cpu); |
Peter Zijlstra | e51fd5e | 2010-05-31 12:37:30 +0200 | [diff] [blame] | 4804 | |
Vincent Guittot | bd61c98 | 2014-08-26 13:06:50 +0200 | [diff] [blame] | 4805 | prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2; |
| 4806 | prev_eff_load *= capacity_of(this_cpu); |
| 4807 | |
| 4808 | if (this_load > 0) { |
Peter Zijlstra | e51fd5e | 2010-05-31 12:37:30 +0200 | [diff] [blame] | 4809 | this_eff_load *= this_load + |
| 4810 | effective_load(tg, this_cpu, weight, weight); |
| 4811 | |
Peter Zijlstra | e51fd5e | 2010-05-31 12:37:30 +0200 | [diff] [blame] | 4812 | prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight); |
Vincent Guittot | bd61c98 | 2014-08-26 13:06:50 +0200 | [diff] [blame] | 4813 | } |
Peter Zijlstra | e51fd5e | 2010-05-31 12:37:30 +0200 | [diff] [blame] | 4814 | |
Vincent Guittot | bd61c98 | 2014-08-26 13:06:50 +0200 | [diff] [blame] | 4815 | balanced = this_eff_load <= prev_eff_load; |
Mike Galbraith | b3137bc | 2008-05-29 11:11:41 +0200 | [diff] [blame] | 4816 | |
Lucas De Marchi | 41acab8 | 2010-03-10 23:37:45 -0300 | [diff] [blame] | 4817 | schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts); |
Mike Galbraith | b3137bc | 2008-05-29 11:11:41 +0200 | [diff] [blame] | 4818 | |
Vincent Guittot | 05bfb65 | 2014-08-26 13:06:45 +0200 | [diff] [blame] | 4819 | if (!balanced) |
| 4820 | return 0; |
Ingo Molnar | 098fb9d | 2008-03-16 20:36:10 +0100 | [diff] [blame] | 4821 | |
Vincent Guittot | 05bfb65 | 2014-08-26 13:06:45 +0200 | [diff] [blame] | 4822 | schedstat_inc(sd, ttwu_move_affine); |
| 4823 | schedstat_inc(p, se.statistics.nr_wakeups_affine); |
| 4824 | |
| 4825 | return 1; |
Ingo Molnar | 098fb9d | 2008-03-16 20:36:10 +0100 | [diff] [blame] | 4826 | } |
| 4827 | |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 4828 | /* |
| 4829 | * find_idlest_group finds and returns the least busy CPU group within the |
| 4830 | * domain. |
| 4831 | */ |
| 4832 | static struct sched_group * |
Peter Zijlstra | 78e7ed5 | 2009-09-03 13:16:51 +0200 | [diff] [blame] | 4833 | find_idlest_group(struct sched_domain *sd, struct task_struct *p, |
Vincent Guittot | c44f2a0 | 2013-10-18 13:52:21 +0200 | [diff] [blame] | 4834 | int this_cpu, int sd_flag) |
Gregory Haskins | e7693a3 | 2008-01-25 21:08:09 +0100 | [diff] [blame] | 4835 | { |
Andi Kleen | b3bd3de | 2010-08-10 14:17:51 -0700 | [diff] [blame] | 4836 | struct sched_group *idlest = NULL, *group = sd->groups; |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 4837 | unsigned long min_load = ULONG_MAX, this_load = 0; |
Vincent Guittot | c44f2a0 | 2013-10-18 13:52:21 +0200 | [diff] [blame] | 4838 | int load_idx = sd->forkexec_idx; |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 4839 | int imbalance = 100 + (sd->imbalance_pct-100)/2; |
Gregory Haskins | e7693a3 | 2008-01-25 21:08:09 +0100 | [diff] [blame] | 4840 | |
Vincent Guittot | c44f2a0 | 2013-10-18 13:52:21 +0200 | [diff] [blame] | 4841 | if (sd_flag & SD_BALANCE_WAKE) |
| 4842 | load_idx = sd->wake_idx; |
| 4843 | |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 4844 | do { |
| 4845 | unsigned long load, avg_load; |
| 4846 | int local_group; |
| 4847 | int i; |
Gregory Haskins | e7693a3 | 2008-01-25 21:08:09 +0100 | [diff] [blame] | 4848 | |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 4849 | /* Skip over this group if it has no CPUs allowed */ |
| 4850 | if (!cpumask_intersects(sched_group_cpus(group), |
Peter Zijlstra | fa17b50 | 2011-06-16 12:23:22 +0200 | [diff] [blame] | 4851 | tsk_cpus_allowed(p))) |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 4852 | continue; |
| 4853 | |
| 4854 | local_group = cpumask_test_cpu(this_cpu, |
| 4855 | sched_group_cpus(group)); |
| 4856 | |
| 4857 | /* Tally up the load of all CPUs in the group */ |
| 4858 | avg_load = 0; |
| 4859 | |
| 4860 | for_each_cpu(i, sched_group_cpus(group)) { |
| 4861 | /* Bias balancing toward cpus of our domain */ |
| 4862 | if (local_group) |
| 4863 | load = source_load(i, load_idx); |
| 4864 | else |
| 4865 | load = target_load(i, load_idx); |
| 4866 | |
| 4867 | avg_load += load; |
| 4868 | } |
| 4869 | |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 4870 | /* Adjust by relative CPU capacity of the group */ |
Nicolas Pitre | ca8ce3d | 2014-05-26 18:19:39 -0400 | [diff] [blame] | 4871 | avg_load = (avg_load * SCHED_CAPACITY_SCALE) / group->sgc->capacity; |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 4872 | |
| 4873 | if (local_group) { |
| 4874 | this_load = avg_load; |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 4875 | } else if (avg_load < min_load) { |
| 4876 | min_load = avg_load; |
| 4877 | idlest = group; |
| 4878 | } |
| 4879 | } while (group = group->next, group != sd->groups); |
| 4880 | |
| 4881 | if (!idlest || 100*this_load < imbalance*min_load) |
| 4882 | return NULL; |
| 4883 | return idlest; |
| 4884 | } |
| 4885 | |
| 4886 | /* |
| 4887 | * find_idlest_cpu - find the idlest cpu among the cpus in group. |
| 4888 | */ |
| 4889 | static int |
| 4890 | find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) |
| 4891 | { |
| 4892 | unsigned long load, min_load = ULONG_MAX; |
Nicolas Pitre | 83a0a96 | 2014-09-04 11:32:10 -0400 | [diff] [blame] | 4893 | unsigned int min_exit_latency = UINT_MAX; |
| 4894 | u64 latest_idle_timestamp = 0; |
| 4895 | int least_loaded_cpu = this_cpu; |
| 4896 | int shallowest_idle_cpu = -1; |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 4897 | int i; |
| 4898 | |
| 4899 | /* Traverse only the allowed CPUs */ |
Peter Zijlstra | fa17b50 | 2011-06-16 12:23:22 +0200 | [diff] [blame] | 4900 | for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) { |
Nicolas Pitre | 83a0a96 | 2014-09-04 11:32:10 -0400 | [diff] [blame] | 4901 | if (idle_cpu(i)) { |
| 4902 | struct rq *rq = cpu_rq(i); |
| 4903 | struct cpuidle_state *idle = idle_get_state(rq); |
| 4904 | if (idle && idle->exit_latency < min_exit_latency) { |
| 4905 | /* |
| 4906 | * We give priority to a CPU whose idle state |
| 4907 | * has the smallest exit latency irrespective |
| 4908 | * of any idle timestamp. |
| 4909 | */ |
| 4910 | min_exit_latency = idle->exit_latency; |
| 4911 | latest_idle_timestamp = rq->idle_stamp; |
| 4912 | shallowest_idle_cpu = i; |
| 4913 | } else if ((!idle || idle->exit_latency == min_exit_latency) && |
| 4914 | rq->idle_stamp > latest_idle_timestamp) { |
| 4915 | /* |
| 4916 | * If equal or no active idle state, then |
| 4917 | * the most recently idled CPU might have |
| 4918 | * a warmer cache. |
| 4919 | */ |
| 4920 | latest_idle_timestamp = rq->idle_stamp; |
| 4921 | shallowest_idle_cpu = i; |
| 4922 | } |
Yao Dongdong | 9f96742 | 2014-10-28 04:08:06 +0000 | [diff] [blame] | 4923 | } else if (shallowest_idle_cpu == -1) { |
Nicolas Pitre | 83a0a96 | 2014-09-04 11:32:10 -0400 | [diff] [blame] | 4924 | load = weighted_cpuload(i); |
| 4925 | if (load < min_load || (load == min_load && i == this_cpu)) { |
| 4926 | min_load = load; |
| 4927 | least_loaded_cpu = i; |
| 4928 | } |
Gregory Haskins | e7693a3 | 2008-01-25 21:08:09 +0100 | [diff] [blame] | 4929 | } |
| 4930 | } |
| 4931 | |
Nicolas Pitre | 83a0a96 | 2014-09-04 11:32:10 -0400 | [diff] [blame] | 4932 | return shallowest_idle_cpu != -1 ? shallowest_idle_cpu : least_loaded_cpu; |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 4933 | } |
Gregory Haskins | e7693a3 | 2008-01-25 21:08:09 +0100 | [diff] [blame] | 4934 | |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 4935 | /* |
Peter Zijlstra | a50bde5 | 2009-11-12 15:55:28 +0100 | [diff] [blame] | 4936 | * Try and locate an idle CPU in the sched_domain. |
| 4937 | */ |
Suresh Siddha | 99bd5e2f | 2010-03-31 16:47:45 -0700 | [diff] [blame] | 4938 | static int select_idle_sibling(struct task_struct *p, int target) |
Peter Zijlstra | a50bde5 | 2009-11-12 15:55:28 +0100 | [diff] [blame] | 4939 | { |
Suresh Siddha | 99bd5e2f | 2010-03-31 16:47:45 -0700 | [diff] [blame] | 4940 | struct sched_domain *sd; |
Linus Torvalds | 37407ea | 2012-09-16 12:29:43 -0700 | [diff] [blame] | 4941 | struct sched_group *sg; |
Mike Galbraith | e0a79f5 | 2013-01-28 12:19:25 +0100 | [diff] [blame] | 4942 | int i = task_cpu(p); |
| 4943 | |
| 4944 | if (idle_cpu(target)) |
| 4945 | return target; |
Peter Zijlstra | a50bde5 | 2009-11-12 15:55:28 +0100 | [diff] [blame] | 4946 | |
| 4947 | /* |
Mike Galbraith | e0a79f5 | 2013-01-28 12:19:25 +0100 | [diff] [blame] | 4948 | * If the prevous cpu is cache affine and idle, don't be stupid. |
Peter Zijlstra | a50bde5 | 2009-11-12 15:55:28 +0100 | [diff] [blame] | 4949 | */ |
Mike Galbraith | e0a79f5 | 2013-01-28 12:19:25 +0100 | [diff] [blame] | 4950 | if (i != target && cpus_share_cache(i, target) && idle_cpu(i)) |
| 4951 | return i; |
Peter Zijlstra | a50bde5 | 2009-11-12 15:55:28 +0100 | [diff] [blame] | 4952 | |
| 4953 | /* |
Linus Torvalds | 37407ea | 2012-09-16 12:29:43 -0700 | [diff] [blame] | 4954 | * Otherwise, iterate the domains and find an elegible idle cpu. |
Peter Zijlstra | a50bde5 | 2009-11-12 15:55:28 +0100 | [diff] [blame] | 4955 | */ |
Peter Zijlstra | 518cd62 | 2011-12-07 15:07:31 +0100 | [diff] [blame] | 4956 | sd = rcu_dereference(per_cpu(sd_llc, target)); |
Suresh Siddha | 77e8136 | 2011-11-17 11:08:23 -0800 | [diff] [blame] | 4957 | for_each_lower_domain(sd) { |
Linus Torvalds | 37407ea | 2012-09-16 12:29:43 -0700 | [diff] [blame] | 4958 | sg = sd->groups; |
| 4959 | do { |
| 4960 | if (!cpumask_intersects(sched_group_cpus(sg), |
| 4961 | tsk_cpus_allowed(p))) |
| 4962 | goto next; |
Mike Galbraith | 970e178 | 2012-06-12 05:18:32 +0200 | [diff] [blame] | 4963 | |
Linus Torvalds | 37407ea | 2012-09-16 12:29:43 -0700 | [diff] [blame] | 4964 | for_each_cpu(i, sched_group_cpus(sg)) { |
Mike Galbraith | e0a79f5 | 2013-01-28 12:19:25 +0100 | [diff] [blame] | 4965 | if (i == target || !idle_cpu(i)) |
Linus Torvalds | 37407ea | 2012-09-16 12:29:43 -0700 | [diff] [blame] | 4966 | goto next; |
| 4967 | } |
| 4968 | |
| 4969 | target = cpumask_first_and(sched_group_cpus(sg), |
| 4970 | tsk_cpus_allowed(p)); |
| 4971 | goto done; |
| 4972 | next: |
| 4973 | sg = sg->next; |
| 4974 | } while (sg != sd->groups); |
| 4975 | } |
| 4976 | done: |
Peter Zijlstra | a50bde5 | 2009-11-12 15:55:28 +0100 | [diff] [blame] | 4977 | return target; |
| 4978 | } |
Vincent Guittot | 8bb5b00 | 2015-03-04 08:48:47 +0100 | [diff] [blame] | 4979 | /* |
| 4980 | * get_cpu_usage returns the amount of capacity of a CPU that is used by CFS |
| 4981 | * tasks. The unit of the return value must be the one of capacity so we can |
| 4982 | * compare the usage with the capacity of the CPU that is available for CFS |
| 4983 | * task (ie cpu_capacity). |
| 4984 | * cfs.utilization_load_avg is the sum of running time of runnable tasks on a |
| 4985 | * CPU. It represents the amount of utilization of a CPU in the range |
| 4986 | * [0..SCHED_LOAD_SCALE]. The usage of a CPU can't be higher than the full |
| 4987 | * capacity of the CPU because it's about the running time on this CPU. |
| 4988 | * Nevertheless, cfs.utilization_load_avg can be higher than SCHED_LOAD_SCALE |
| 4989 | * because of unfortunate rounding in avg_period and running_load_avg or just |
| 4990 | * after migrating tasks until the average stabilizes with the new running |
| 4991 | * time. So we need to check that the usage stays into the range |
| 4992 | * [0..cpu_capacity_orig] and cap if necessary. |
| 4993 | * Without capping the usage, a group could be seen as overloaded (CPU0 usage |
| 4994 | * at 121% + CPU1 usage at 80%) whereas CPU1 has 20% of available capacity |
| 4995 | */ |
| 4996 | static int get_cpu_usage(int cpu) |
| 4997 | { |
| 4998 | unsigned long usage = cpu_rq(cpu)->cfs.utilization_load_avg; |
| 4999 | unsigned long capacity = capacity_orig_of(cpu); |
| 5000 | |
| 5001 | if (usage >= SCHED_LOAD_SCALE) |
| 5002 | return capacity; |
| 5003 | |
| 5004 | return (usage * capacity) >> SCHED_LOAD_SHIFT; |
| 5005 | } |
Peter Zijlstra | a50bde5 | 2009-11-12 15:55:28 +0100 | [diff] [blame] | 5006 | |
| 5007 | /* |
Morten Rasmussen | de91b9c | 2014-02-18 14:14:24 +0000 | [diff] [blame] | 5008 | * select_task_rq_fair: Select target runqueue for the waking task in domains |
| 5009 | * that have the 'sd_flag' flag set. In practice, this is SD_BALANCE_WAKE, |
| 5010 | * SD_BALANCE_FORK, or SD_BALANCE_EXEC. |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5011 | * |
Morten Rasmussen | de91b9c | 2014-02-18 14:14:24 +0000 | [diff] [blame] | 5012 | * Balances load by selecting the idlest cpu in the idlest group, or under |
| 5013 | * certain conditions an idle sibling cpu if the domain has SD_WAKE_AFFINE set. |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5014 | * |
Morten Rasmussen | de91b9c | 2014-02-18 14:14:24 +0000 | [diff] [blame] | 5015 | * Returns the target cpu number. |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5016 | * |
| 5017 | * preempt must be disabled. |
| 5018 | */ |
Peter Zijlstra | 0017d73 | 2010-03-24 18:34:10 +0100 | [diff] [blame] | 5019 | static int |
Peter Zijlstra | ac66f54 | 2013-10-07 11:29:16 +0100 | [diff] [blame] | 5020 | select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_flags) |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5021 | { |
Peter Zijlstra | 29cd8ba | 2009-09-17 09:01:14 +0200 | [diff] [blame] | 5022 | struct sched_domain *tmp, *affine_sd = NULL, *sd = NULL; |
Peter Zijlstra | c88d591 | 2009-09-10 13:50:02 +0200 | [diff] [blame] | 5023 | int cpu = smp_processor_id(); |
Peter Zijlstra | c88d591 | 2009-09-10 13:50:02 +0200 | [diff] [blame] | 5024 | int new_cpu = cpu; |
Suresh Siddha | 99bd5e2f | 2010-03-31 16:47:45 -0700 | [diff] [blame] | 5025 | int want_affine = 0; |
Peter Zijlstra | 5158f4e | 2009-09-16 13:46:59 +0200 | [diff] [blame] | 5026 | int sync = wake_flags & WF_SYNC; |
Gregory Haskins | e7693a3 | 2008-01-25 21:08:09 +0100 | [diff] [blame] | 5027 | |
Kirill Tkhai | a8edd07 | 2014-09-12 17:41:16 +0400 | [diff] [blame] | 5028 | if (sd_flag & SD_BALANCE_WAKE) |
| 5029 | want_affine = cpumask_test_cpu(cpu, tsk_cpus_allowed(p)); |
Gregory Haskins | e7693a3 | 2008-01-25 21:08:09 +0100 | [diff] [blame] | 5030 | |
Peter Zijlstra | dce840a | 2011-04-07 14:09:50 +0200 | [diff] [blame] | 5031 | rcu_read_lock(); |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5032 | for_each_domain(cpu, tmp) { |
Peter Zijlstra | e4f4288 | 2009-12-16 18:04:34 +0100 | [diff] [blame] | 5033 | if (!(tmp->flags & SD_LOAD_BALANCE)) |
| 5034 | continue; |
| 5035 | |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5036 | /* |
Suresh Siddha | 99bd5e2f | 2010-03-31 16:47:45 -0700 | [diff] [blame] | 5037 | * If both cpu and prev_cpu are part of this domain, |
| 5038 | * cpu is a valid SD_WAKE_AFFINE target. |
Peter Zijlstra | fe3bcfe | 2009-11-12 15:55:29 +0100 | [diff] [blame] | 5039 | */ |
Suresh Siddha | 99bd5e2f | 2010-03-31 16:47:45 -0700 | [diff] [blame] | 5040 | if (want_affine && (tmp->flags & SD_WAKE_AFFINE) && |
| 5041 | cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) { |
| 5042 | affine_sd = tmp; |
Alex Shi | f03542a | 2012-07-26 08:55:34 +0800 | [diff] [blame] | 5043 | break; |
Peter Zijlstra | c88d591 | 2009-09-10 13:50:02 +0200 | [diff] [blame] | 5044 | } |
| 5045 | |
Alex Shi | f03542a | 2012-07-26 08:55:34 +0800 | [diff] [blame] | 5046 | if (tmp->flags & sd_flag) |
Peter Zijlstra | 29cd8ba | 2009-09-17 09:01:14 +0200 | [diff] [blame] | 5047 | sd = tmp; |
Peter Zijlstra | c88d591 | 2009-09-10 13:50:02 +0200 | [diff] [blame] | 5048 | } |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5049 | |
Rik van Riel | 8bf2143 | 2014-05-14 11:40:37 -0400 | [diff] [blame] | 5050 | if (affine_sd && cpu != prev_cpu && wake_affine(affine_sd, p, sync)) |
| 5051 | prev_cpu = cpu; |
Peter Zijlstra | dce840a | 2011-04-07 14:09:50 +0200 | [diff] [blame] | 5052 | |
Rik van Riel | 8bf2143 | 2014-05-14 11:40:37 -0400 | [diff] [blame] | 5053 | if (sd_flag & SD_BALANCE_WAKE) { |
Peter Zijlstra | dce840a | 2011-04-07 14:09:50 +0200 | [diff] [blame] | 5054 | new_cpu = select_idle_sibling(p, prev_cpu); |
| 5055 | goto unlock; |
Mike Galbraith | 8b911ac | 2010-03-11 17:17:16 +0100 | [diff] [blame] | 5056 | } |
Peter Zijlstra | 3b64089 | 2009-09-16 13:44:33 +0200 | [diff] [blame] | 5057 | |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5058 | while (sd) { |
| 5059 | struct sched_group *group; |
Peter Zijlstra | c88d591 | 2009-09-10 13:50:02 +0200 | [diff] [blame] | 5060 | int weight; |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5061 | |
Peter Zijlstra | 0763a66 | 2009-09-14 19:37:39 +0200 | [diff] [blame] | 5062 | if (!(sd->flags & sd_flag)) { |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5063 | sd = sd->child; |
| 5064 | continue; |
| 5065 | } |
| 5066 | |
Vincent Guittot | c44f2a0 | 2013-10-18 13:52:21 +0200 | [diff] [blame] | 5067 | group = find_idlest_group(sd, p, cpu, sd_flag); |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5068 | if (!group) { |
| 5069 | sd = sd->child; |
| 5070 | continue; |
| 5071 | } |
| 5072 | |
Peter Zijlstra | d7c33c4 | 2009-09-11 12:45:38 +0200 | [diff] [blame] | 5073 | new_cpu = find_idlest_cpu(group, p, cpu); |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5074 | if (new_cpu == -1 || new_cpu == cpu) { |
| 5075 | /* Now try balancing at a lower domain level of cpu */ |
| 5076 | sd = sd->child; |
| 5077 | continue; |
| 5078 | } |
| 5079 | |
| 5080 | /* Now try balancing at a lower domain level of new_cpu */ |
| 5081 | cpu = new_cpu; |
Peter Zijlstra | 669c55e | 2010-04-16 14:59:29 +0200 | [diff] [blame] | 5082 | weight = sd->span_weight; |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5083 | sd = NULL; |
| 5084 | for_each_domain(cpu, tmp) { |
Peter Zijlstra | 669c55e | 2010-04-16 14:59:29 +0200 | [diff] [blame] | 5085 | if (weight <= tmp->span_weight) |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5086 | break; |
Peter Zijlstra | 0763a66 | 2009-09-14 19:37:39 +0200 | [diff] [blame] | 5087 | if (tmp->flags & sd_flag) |
Peter Zijlstra | aaee120 | 2009-09-10 13:36:25 +0200 | [diff] [blame] | 5088 | sd = tmp; |
| 5089 | } |
| 5090 | /* while loop will break here if sd == NULL */ |
Gregory Haskins | e7693a3 | 2008-01-25 21:08:09 +0100 | [diff] [blame] | 5091 | } |
Peter Zijlstra | dce840a | 2011-04-07 14:09:50 +0200 | [diff] [blame] | 5092 | unlock: |
| 5093 | rcu_read_unlock(); |
Gregory Haskins | e7693a3 | 2008-01-25 21:08:09 +0100 | [diff] [blame] | 5094 | |
Peter Zijlstra | c88d591 | 2009-09-10 13:50:02 +0200 | [diff] [blame] | 5095 | return new_cpu; |
Gregory Haskins | e7693a3 | 2008-01-25 21:08:09 +0100 | [diff] [blame] | 5096 | } |
Paul Turner | 0a74bef | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 5097 | |
| 5098 | /* |
| 5099 | * Called immediately before a task is migrated to a new cpu; task_cpu(p) and |
| 5100 | * cfs_rq_of(p) references at time of call are still valid and identify the |
| 5101 | * previous cpu. However, the caller only guarantees p->pi_lock is held; no |
| 5102 | * other assumptions, including the state of rq->lock, should be made. |
| 5103 | */ |
| 5104 | static void |
| 5105 | migrate_task_rq_fair(struct task_struct *p, int next_cpu) |
| 5106 | { |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 5107 | struct sched_entity *se = &p->se; |
| 5108 | struct cfs_rq *cfs_rq = cfs_rq_of(se); |
| 5109 | |
| 5110 | /* |
| 5111 | * Load tracking: accumulate removed load so that it can be processed |
| 5112 | * when we next update owning cfs_rq under rq->lock. Tasks contribute |
| 5113 | * to blocked load iff they have a positive decay-count. It can never |
| 5114 | * be negative here since on-rq tasks have decay-count == 0. |
| 5115 | */ |
| 5116 | if (se->avg.decay_count) { |
| 5117 | se->avg.decay_count = -__synchronize_entity_decay(se); |
Alex Shi | 2509940 | 2013-06-20 10:18:55 +0800 | [diff] [blame] | 5118 | atomic_long_add(se->avg.load_avg_contrib, |
| 5119 | &cfs_rq->removed_load); |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 5120 | } |
Ben Segall | 3944a92 | 2014-05-15 15:59:20 -0700 | [diff] [blame] | 5121 | |
| 5122 | /* We have migrated, no longer consider this task hot */ |
| 5123 | se->exec_start = 0; |
Paul Turner | 0a74bef | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 5124 | } |
Gregory Haskins | e7693a3 | 2008-01-25 21:08:09 +0100 | [diff] [blame] | 5125 | #endif /* CONFIG_SMP */ |
| 5126 | |
Peter Zijlstra | e52fb7c | 2009-01-14 12:39:19 +0100 | [diff] [blame] | 5127 | static unsigned long |
| 5128 | wakeup_gran(struct sched_entity *curr, struct sched_entity *se) |
Peter Zijlstra | 0bbd3336 | 2008-04-19 19:44:57 +0200 | [diff] [blame] | 5129 | { |
| 5130 | unsigned long gran = sysctl_sched_wakeup_granularity; |
| 5131 | |
| 5132 | /* |
Peter Zijlstra | e52fb7c | 2009-01-14 12:39:19 +0100 | [diff] [blame] | 5133 | * Since its curr running now, convert the gran from real-time |
| 5134 | * to virtual-time in his units. |
Mike Galbraith | 13814d4 | 2010-03-11 17:17:04 +0100 | [diff] [blame] | 5135 | * |
| 5136 | * By using 'se' instead of 'curr' we penalize light tasks, so |
| 5137 | * they get preempted easier. That is, if 'se' < 'curr' then |
| 5138 | * the resulting gran will be larger, therefore penalizing the |
| 5139 | * lighter, if otoh 'se' > 'curr' then the resulting gran will |
| 5140 | * be smaller, again penalizing the lighter task. |
| 5141 | * |
| 5142 | * This is especially important for buddies when the leftmost |
| 5143 | * task is higher priority than the buddy. |
Peter Zijlstra | 0bbd3336 | 2008-04-19 19:44:57 +0200 | [diff] [blame] | 5144 | */ |
Shaohua Li | f4ad9bd | 2011-04-08 12:53:09 +0800 | [diff] [blame] | 5145 | return calc_delta_fair(gran, se); |
Peter Zijlstra | 0bbd3336 | 2008-04-19 19:44:57 +0200 | [diff] [blame] | 5146 | } |
| 5147 | |
| 5148 | /* |
Peter Zijlstra | 464b752 | 2008-10-24 11:06:15 +0200 | [diff] [blame] | 5149 | * Should 'se' preempt 'curr'. |
| 5150 | * |
| 5151 | * |s1 |
| 5152 | * |s2 |
| 5153 | * |s3 |
| 5154 | * g |
| 5155 | * |<--->|c |
| 5156 | * |
| 5157 | * w(c, s1) = -1 |
| 5158 | * w(c, s2) = 0 |
| 5159 | * w(c, s3) = 1 |
| 5160 | * |
| 5161 | */ |
| 5162 | static int |
| 5163 | wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se) |
| 5164 | { |
| 5165 | s64 gran, vdiff = curr->vruntime - se->vruntime; |
| 5166 | |
| 5167 | if (vdiff <= 0) |
| 5168 | return -1; |
| 5169 | |
Peter Zijlstra | e52fb7c | 2009-01-14 12:39:19 +0100 | [diff] [blame] | 5170 | gran = wakeup_gran(curr, se); |
Peter Zijlstra | 464b752 | 2008-10-24 11:06:15 +0200 | [diff] [blame] | 5171 | if (vdiff > gran) |
| 5172 | return 1; |
| 5173 | |
| 5174 | return 0; |
| 5175 | } |
| 5176 | |
Peter Zijlstra | 0247909 | 2008-11-04 21:25:10 +0100 | [diff] [blame] | 5177 | static void set_last_buddy(struct sched_entity *se) |
| 5178 | { |
Venkatesh Pallipadi | 69c80f3 | 2011-04-13 18:21:09 -0700 | [diff] [blame] | 5179 | if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE)) |
| 5180 | return; |
| 5181 | |
| 5182 | for_each_sched_entity(se) |
| 5183 | cfs_rq_of(se)->last = se; |
Peter Zijlstra | 0247909 | 2008-11-04 21:25:10 +0100 | [diff] [blame] | 5184 | } |
| 5185 | |
| 5186 | static void set_next_buddy(struct sched_entity *se) |
| 5187 | { |
Venkatesh Pallipadi | 69c80f3 | 2011-04-13 18:21:09 -0700 | [diff] [blame] | 5188 | if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE)) |
| 5189 | return; |
| 5190 | |
| 5191 | for_each_sched_entity(se) |
| 5192 | cfs_rq_of(se)->next = se; |
Peter Zijlstra | 0247909 | 2008-11-04 21:25:10 +0100 | [diff] [blame] | 5193 | } |
| 5194 | |
Rik van Riel | ac53db5 | 2011-02-01 09:51:03 -0500 | [diff] [blame] | 5195 | static void set_skip_buddy(struct sched_entity *se) |
| 5196 | { |
Venkatesh Pallipadi | 69c80f3 | 2011-04-13 18:21:09 -0700 | [diff] [blame] | 5197 | for_each_sched_entity(se) |
| 5198 | cfs_rq_of(se)->skip = se; |
Rik van Riel | ac53db5 | 2011-02-01 09:51:03 -0500 | [diff] [blame] | 5199 | } |
| 5200 | |
Peter Zijlstra | 464b752 | 2008-10-24 11:06:15 +0200 | [diff] [blame] | 5201 | /* |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 5202 | * Preempt the current task with a newly woken task if needed: |
| 5203 | */ |
Peter Zijlstra | 5a9b86f | 2009-09-16 13:47:58 +0200 | [diff] [blame] | 5204 | static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 5205 | { |
| 5206 | struct task_struct *curr = rq->curr; |
Srivatsa Vaddagiri | 8651a86 | 2007-10-15 17:00:12 +0200 | [diff] [blame] | 5207 | struct sched_entity *se = &curr->se, *pse = &p->se; |
Mike Galbraith | 03e89e4 | 2008-12-16 08:45:30 +0100 | [diff] [blame] | 5208 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); |
Mike Galbraith | f685cea | 2009-10-23 23:09:22 +0200 | [diff] [blame] | 5209 | int scale = cfs_rq->nr_running >= sched_nr_latency; |
Venkatesh Pallipadi | 2f36825 | 2011-04-14 10:30:53 -0700 | [diff] [blame] | 5210 | int next_buddy_marked = 0; |
Mike Galbraith | 03e89e4 | 2008-12-16 08:45:30 +0100 | [diff] [blame] | 5211 | |
Ingo Molnar | 4ae7d5c | 2008-03-19 01:42:00 +0100 | [diff] [blame] | 5212 | if (unlikely(se == pse)) |
| 5213 | return; |
| 5214 | |
Paul Turner | 5238cdd | 2011-07-21 09:43:37 -0700 | [diff] [blame] | 5215 | /* |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5216 | * This is possible from callers such as attach_tasks(), in which we |
Paul Turner | 5238cdd | 2011-07-21 09:43:37 -0700 | [diff] [blame] | 5217 | * unconditionally check_prempt_curr() after an enqueue (which may have |
| 5218 | * lead to a throttle). This both saves work and prevents false |
| 5219 | * next-buddy nomination below. |
| 5220 | */ |
| 5221 | if (unlikely(throttled_hierarchy(cfs_rq_of(pse)))) |
| 5222 | return; |
| 5223 | |
Venkatesh Pallipadi | 2f36825 | 2011-04-14 10:30:53 -0700 | [diff] [blame] | 5224 | if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) { |
Mike Galbraith | 3cb63d5 | 2009-09-11 12:01:17 +0200 | [diff] [blame] | 5225 | set_next_buddy(pse); |
Venkatesh Pallipadi | 2f36825 | 2011-04-14 10:30:53 -0700 | [diff] [blame] | 5226 | next_buddy_marked = 1; |
| 5227 | } |
Peter Zijlstra | 57fdc26 | 2008-09-23 15:33:45 +0200 | [diff] [blame] | 5228 | |
Bharata B Rao | aec0a514 | 2008-08-28 14:42:49 +0530 | [diff] [blame] | 5229 | /* |
| 5230 | * We can come here with TIF_NEED_RESCHED already set from new task |
| 5231 | * wake up path. |
Paul Turner | 5238cdd | 2011-07-21 09:43:37 -0700 | [diff] [blame] | 5232 | * |
| 5233 | * Note: this also catches the edge-case of curr being in a throttled |
| 5234 | * group (e.g. via set_curr_task), since update_curr() (in the |
| 5235 | * enqueue of curr) will have resulted in resched being set. This |
| 5236 | * prevents us from potentially nominating it as a false LAST_BUDDY |
| 5237 | * below. |
Bharata B Rao | aec0a514 | 2008-08-28 14:42:49 +0530 | [diff] [blame] | 5238 | */ |
| 5239 | if (test_tsk_need_resched(curr)) |
| 5240 | return; |
| 5241 | |
Darren Hart | a2f5c9a | 2011-02-22 13:04:33 -0800 | [diff] [blame] | 5242 | /* Idle tasks are by definition preempted by non-idle tasks. */ |
| 5243 | if (unlikely(curr->policy == SCHED_IDLE) && |
| 5244 | likely(p->policy != SCHED_IDLE)) |
| 5245 | goto preempt; |
| 5246 | |
Ingo Molnar | 91c234b | 2007-10-15 17:00:18 +0200 | [diff] [blame] | 5247 | /* |
Darren Hart | a2f5c9a | 2011-02-22 13:04:33 -0800 | [diff] [blame] | 5248 | * Batch and idle tasks do not preempt non-idle tasks (their preemption |
| 5249 | * is driven by the tick): |
Ingo Molnar | 91c234b | 2007-10-15 17:00:18 +0200 | [diff] [blame] | 5250 | */ |
Ingo Molnar | 8ed92e5 | 2012-10-14 14:28:50 +0200 | [diff] [blame] | 5251 | if (unlikely(p->policy != SCHED_NORMAL) || !sched_feat(WAKEUP_PREEMPTION)) |
Ingo Molnar | 91c234b | 2007-10-15 17:00:18 +0200 | [diff] [blame] | 5252 | return; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 5253 | |
Peter Zijlstra | 3a7e73a | 2009-11-28 18:51:02 +0100 | [diff] [blame] | 5254 | find_matching_se(&se, &pse); |
Paul Turner | 9bbd737 | 2011-07-05 19:07:21 -0700 | [diff] [blame] | 5255 | update_curr(cfs_rq_of(se)); |
Peter Zijlstra | 3a7e73a | 2009-11-28 18:51:02 +0100 | [diff] [blame] | 5256 | BUG_ON(!pse); |
Venkatesh Pallipadi | 2f36825 | 2011-04-14 10:30:53 -0700 | [diff] [blame] | 5257 | if (wakeup_preempt_entity(se, pse) == 1) { |
| 5258 | /* |
| 5259 | * Bias pick_next to pick the sched entity that is |
| 5260 | * triggering this preemption. |
| 5261 | */ |
| 5262 | if (!next_buddy_marked) |
| 5263 | set_next_buddy(pse); |
Peter Zijlstra | 3a7e73a | 2009-11-28 18:51:02 +0100 | [diff] [blame] | 5264 | goto preempt; |
Venkatesh Pallipadi | 2f36825 | 2011-04-14 10:30:53 -0700 | [diff] [blame] | 5265 | } |
Jupyung Lee | a65ac745 | 2009-11-17 18:51:40 +0900 | [diff] [blame] | 5266 | |
Peter Zijlstra | 3a7e73a | 2009-11-28 18:51:02 +0100 | [diff] [blame] | 5267 | return; |
| 5268 | |
| 5269 | preempt: |
Kirill Tkhai | 8875125 | 2014-06-29 00:03:57 +0400 | [diff] [blame] | 5270 | resched_curr(rq); |
Peter Zijlstra | 3a7e73a | 2009-11-28 18:51:02 +0100 | [diff] [blame] | 5271 | /* |
| 5272 | * Only set the backward buddy when the current task is still |
| 5273 | * on the rq. This can happen when a wakeup gets interleaved |
| 5274 | * with schedule on the ->pre_schedule() or idle_balance() |
| 5275 | * point, either of which can * drop the rq lock. |
| 5276 | * |
| 5277 | * Also, during early boot the idle thread is in the fair class, |
| 5278 | * for obvious reasons its a bad idea to schedule back to it. |
| 5279 | */ |
| 5280 | if (unlikely(!se->on_rq || curr == rq->idle)) |
| 5281 | return; |
| 5282 | |
| 5283 | if (sched_feat(LAST_BUDDY) && scale && entity_is_task(se)) |
| 5284 | set_last_buddy(se); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 5285 | } |
| 5286 | |
Peter Zijlstra | 606dba2 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 5287 | static struct task_struct * |
| 5288 | pick_next_task_fair(struct rq *rq, struct task_struct *prev) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 5289 | { |
| 5290 | struct cfs_rq *cfs_rq = &rq->cfs; |
| 5291 | struct sched_entity *se; |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 5292 | struct task_struct *p; |
Peter Zijlstra | 37e117c | 2014-02-14 12:25:08 +0100 | [diff] [blame] | 5293 | int new_tasks; |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 5294 | |
Peter Zijlstra | 6e83125 | 2014-02-11 16:11:48 +0100 | [diff] [blame] | 5295 | again: |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 5296 | #ifdef CONFIG_FAIR_GROUP_SCHED |
| 5297 | if (!cfs_rq->nr_running) |
Peter Zijlstra | 38033c3 | 2014-01-23 20:32:21 +0100 | [diff] [blame] | 5298 | goto idle; |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 5299 | |
Peter Zijlstra | 3f1d2a3 | 2014-02-12 10:49:30 +0100 | [diff] [blame] | 5300 | if (prev->sched_class != &fair_sched_class) |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 5301 | goto simple; |
| 5302 | |
| 5303 | /* |
| 5304 | * Because of the set_next_buddy() in dequeue_task_fair() it is rather |
| 5305 | * likely that a next task is from the same cgroup as the current. |
| 5306 | * |
| 5307 | * Therefore attempt to avoid putting and setting the entire cgroup |
| 5308 | * hierarchy, only change the part that actually changes. |
| 5309 | */ |
| 5310 | |
| 5311 | do { |
| 5312 | struct sched_entity *curr = cfs_rq->curr; |
| 5313 | |
| 5314 | /* |
| 5315 | * Since we got here without doing put_prev_entity() we also |
| 5316 | * have to consider cfs_rq->curr. If it is still a runnable |
| 5317 | * entity, update_curr() will update its vruntime, otherwise |
| 5318 | * forget we've ever seen it. |
| 5319 | */ |
Ben Segall | 54d2736 | 2015-04-06 15:28:10 -0700 | [diff] [blame] | 5320 | if (curr) { |
| 5321 | if (curr->on_rq) |
| 5322 | update_curr(cfs_rq); |
| 5323 | else |
| 5324 | curr = NULL; |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 5325 | |
Ben Segall | 54d2736 | 2015-04-06 15:28:10 -0700 | [diff] [blame] | 5326 | /* |
| 5327 | * This call to check_cfs_rq_runtime() will do the |
| 5328 | * throttle and dequeue its entity in the parent(s). |
| 5329 | * Therefore the 'simple' nr_running test will indeed |
| 5330 | * be correct. |
| 5331 | */ |
| 5332 | if (unlikely(check_cfs_rq_runtime(cfs_rq))) |
| 5333 | goto simple; |
| 5334 | } |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 5335 | |
| 5336 | se = pick_next_entity(cfs_rq, curr); |
| 5337 | cfs_rq = group_cfs_rq(se); |
| 5338 | } while (cfs_rq); |
| 5339 | |
| 5340 | p = task_of(se); |
| 5341 | |
| 5342 | /* |
| 5343 | * Since we haven't yet done put_prev_entity and if the selected task |
| 5344 | * is a different task than we started out with, try and touch the |
| 5345 | * least amount of cfs_rqs. |
| 5346 | */ |
| 5347 | if (prev != p) { |
| 5348 | struct sched_entity *pse = &prev->se; |
| 5349 | |
| 5350 | while (!(cfs_rq = is_same_group(se, pse))) { |
| 5351 | int se_depth = se->depth; |
| 5352 | int pse_depth = pse->depth; |
| 5353 | |
| 5354 | if (se_depth <= pse_depth) { |
| 5355 | put_prev_entity(cfs_rq_of(pse), pse); |
| 5356 | pse = parent_entity(pse); |
| 5357 | } |
| 5358 | if (se_depth >= pse_depth) { |
| 5359 | set_next_entity(cfs_rq_of(se), se); |
| 5360 | se = parent_entity(se); |
| 5361 | } |
| 5362 | } |
| 5363 | |
| 5364 | put_prev_entity(cfs_rq, pse); |
| 5365 | set_next_entity(cfs_rq, se); |
| 5366 | } |
| 5367 | |
| 5368 | if (hrtick_enabled(rq)) |
| 5369 | hrtick_start_fair(rq, p); |
| 5370 | |
| 5371 | return p; |
| 5372 | simple: |
| 5373 | cfs_rq = &rq->cfs; |
| 5374 | #endif |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 5375 | |
Tim Blechmann | 36ace27 | 2009-11-24 11:55:45 +0100 | [diff] [blame] | 5376 | if (!cfs_rq->nr_running) |
Peter Zijlstra | 38033c3 | 2014-01-23 20:32:21 +0100 | [diff] [blame] | 5377 | goto idle; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 5378 | |
Peter Zijlstra | 3f1d2a3 | 2014-02-12 10:49:30 +0100 | [diff] [blame] | 5379 | put_prev_task(rq, prev); |
Peter Zijlstra | 606dba2 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 5380 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 5381 | do { |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 5382 | se = pick_next_entity(cfs_rq, NULL); |
Peter Zijlstra | f4b6755 | 2008-11-04 21:25:07 +0100 | [diff] [blame] | 5383 | set_next_entity(cfs_rq, se); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 5384 | cfs_rq = group_cfs_rq(se); |
| 5385 | } while (cfs_rq); |
| 5386 | |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 5387 | p = task_of(se); |
Peter Zijlstra | 678d571 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 5388 | |
Mike Galbraith | b39e66e | 2011-11-22 15:20:07 +0100 | [diff] [blame] | 5389 | if (hrtick_enabled(rq)) |
| 5390 | hrtick_start_fair(rq, p); |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 5391 | |
| 5392 | return p; |
Peter Zijlstra | 38033c3 | 2014-01-23 20:32:21 +0100 | [diff] [blame] | 5393 | |
| 5394 | idle: |
Peter Zijlstra | cbce1a6 | 2015-06-11 14:46:54 +0200 | [diff] [blame] | 5395 | /* |
| 5396 | * This is OK, because current is on_cpu, which avoids it being picked |
| 5397 | * for load-balance and preemption/IRQs are still disabled avoiding |
| 5398 | * further scheduler activity on it and we're being very careful to |
| 5399 | * re-start the picking loop. |
| 5400 | */ |
| 5401 | lockdep_unpin_lock(&rq->lock); |
Kirill Tkhai | e4aa358 | 2014-03-06 13:31:55 +0400 | [diff] [blame] | 5402 | new_tasks = idle_balance(rq); |
Peter Zijlstra | cbce1a6 | 2015-06-11 14:46:54 +0200 | [diff] [blame] | 5403 | lockdep_pin_lock(&rq->lock); |
Peter Zijlstra | 37e117c | 2014-02-14 12:25:08 +0100 | [diff] [blame] | 5404 | /* |
| 5405 | * Because idle_balance() releases (and re-acquires) rq->lock, it is |
| 5406 | * possible for any higher priority task to appear. In that case we |
| 5407 | * must re-start the pick_next_entity() loop. |
| 5408 | */ |
Kirill Tkhai | e4aa358 | 2014-03-06 13:31:55 +0400 | [diff] [blame] | 5409 | if (new_tasks < 0) |
Peter Zijlstra | 37e117c | 2014-02-14 12:25:08 +0100 | [diff] [blame] | 5410 | return RETRY_TASK; |
| 5411 | |
Kirill Tkhai | e4aa358 | 2014-03-06 13:31:55 +0400 | [diff] [blame] | 5412 | if (new_tasks > 0) |
Peter Zijlstra | 38033c3 | 2014-01-23 20:32:21 +0100 | [diff] [blame] | 5413 | goto again; |
Peter Zijlstra | 38033c3 | 2014-01-23 20:32:21 +0100 | [diff] [blame] | 5414 | |
| 5415 | return NULL; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 5416 | } |
| 5417 | |
| 5418 | /* |
| 5419 | * Account for a descheduled task: |
| 5420 | */ |
Ingo Molnar | 31ee529 | 2007-08-09 11:16:49 +0200 | [diff] [blame] | 5421 | static void put_prev_task_fair(struct rq *rq, struct task_struct *prev) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 5422 | { |
| 5423 | struct sched_entity *se = &prev->se; |
| 5424 | struct cfs_rq *cfs_rq; |
| 5425 | |
| 5426 | for_each_sched_entity(se) { |
| 5427 | cfs_rq = cfs_rq_of(se); |
Ingo Molnar | ab6cde2 | 2007-08-09 11:16:48 +0200 | [diff] [blame] | 5428 | put_prev_entity(cfs_rq, se); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 5429 | } |
| 5430 | } |
| 5431 | |
Rik van Riel | ac53db5 | 2011-02-01 09:51:03 -0500 | [diff] [blame] | 5432 | /* |
| 5433 | * sched_yield() is very simple |
| 5434 | * |
| 5435 | * The magic of dealing with the ->skip buddy is in pick_next_entity. |
| 5436 | */ |
| 5437 | static void yield_task_fair(struct rq *rq) |
| 5438 | { |
| 5439 | struct task_struct *curr = rq->curr; |
| 5440 | struct cfs_rq *cfs_rq = task_cfs_rq(curr); |
| 5441 | struct sched_entity *se = &curr->se; |
| 5442 | |
| 5443 | /* |
| 5444 | * Are we the only task in the tree? |
| 5445 | */ |
| 5446 | if (unlikely(rq->nr_running == 1)) |
| 5447 | return; |
| 5448 | |
| 5449 | clear_buddies(cfs_rq, se); |
| 5450 | |
| 5451 | if (curr->policy != SCHED_BATCH) { |
| 5452 | update_rq_clock(rq); |
| 5453 | /* |
| 5454 | * Update run-time statistics of the 'current'. |
| 5455 | */ |
| 5456 | update_curr(cfs_rq); |
Mike Galbraith | 916671c | 2011-11-22 15:21:26 +0100 | [diff] [blame] | 5457 | /* |
| 5458 | * Tell update_rq_clock() that we've just updated, |
| 5459 | * so we don't do microscopic update in schedule() |
| 5460 | * and double the fastpath cost. |
| 5461 | */ |
Peter Zijlstra | 9edfbfe | 2015-01-05 11:18:11 +0100 | [diff] [blame] | 5462 | rq_clock_skip_update(rq, true); |
Rik van Riel | ac53db5 | 2011-02-01 09:51:03 -0500 | [diff] [blame] | 5463 | } |
| 5464 | |
| 5465 | set_skip_buddy(se); |
| 5466 | } |
| 5467 | |
Mike Galbraith | d95f412 | 2011-02-01 09:50:51 -0500 | [diff] [blame] | 5468 | static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preempt) |
| 5469 | { |
| 5470 | struct sched_entity *se = &p->se; |
| 5471 | |
Paul Turner | 5238cdd | 2011-07-21 09:43:37 -0700 | [diff] [blame] | 5472 | /* throttled hierarchies are not runnable */ |
| 5473 | if (!se->on_rq || throttled_hierarchy(cfs_rq_of(se))) |
Mike Galbraith | d95f412 | 2011-02-01 09:50:51 -0500 | [diff] [blame] | 5474 | return false; |
| 5475 | |
| 5476 | /* Tell the scheduler that we'd really like pse to run next. */ |
| 5477 | set_next_buddy(se); |
| 5478 | |
Mike Galbraith | d95f412 | 2011-02-01 09:50:51 -0500 | [diff] [blame] | 5479 | yield_task_fair(rq); |
| 5480 | |
| 5481 | return true; |
| 5482 | } |
| 5483 | |
Peter Williams | 681f3e6 | 2007-10-24 18:23:51 +0200 | [diff] [blame] | 5484 | #ifdef CONFIG_SMP |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 5485 | /************************************************** |
Peter Zijlstra | e9c84cb | 2012-07-03 13:53:26 +0200 | [diff] [blame] | 5486 | * Fair scheduling class load-balancing methods. |
| 5487 | * |
| 5488 | * BASICS |
| 5489 | * |
| 5490 | * The purpose of load-balancing is to achieve the same basic fairness the |
| 5491 | * per-cpu scheduler provides, namely provide a proportional amount of compute |
| 5492 | * time to each task. This is expressed in the following equation: |
| 5493 | * |
| 5494 | * W_i,n/P_i == W_j,n/P_j for all i,j (1) |
| 5495 | * |
| 5496 | * Where W_i,n is the n-th weight average for cpu i. The instantaneous weight |
| 5497 | * W_i,0 is defined as: |
| 5498 | * |
| 5499 | * W_i,0 = \Sum_j w_i,j (2) |
| 5500 | * |
| 5501 | * Where w_i,j is the weight of the j-th runnable task on cpu i. This weight |
| 5502 | * is derived from the nice value as per prio_to_weight[]. |
| 5503 | * |
| 5504 | * The weight average is an exponential decay average of the instantaneous |
| 5505 | * weight: |
| 5506 | * |
| 5507 | * W'_i,n = (2^n - 1) / 2^n * W_i,n + 1 / 2^n * W_i,0 (3) |
| 5508 | * |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 5509 | * C_i is the compute capacity of cpu i, typically it is the |
Peter Zijlstra | e9c84cb | 2012-07-03 13:53:26 +0200 | [diff] [blame] | 5510 | * fraction of 'recent' time available for SCHED_OTHER task execution. But it |
| 5511 | * can also include other factors [XXX]. |
| 5512 | * |
| 5513 | * To achieve this balance we define a measure of imbalance which follows |
| 5514 | * directly from (1): |
| 5515 | * |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 5516 | * imb_i,j = max{ avg(W/C), W_i/C_i } - min{ avg(W/C), W_j/C_j } (4) |
Peter Zijlstra | e9c84cb | 2012-07-03 13:53:26 +0200 | [diff] [blame] | 5517 | * |
| 5518 | * We them move tasks around to minimize the imbalance. In the continuous |
| 5519 | * function space it is obvious this converges, in the discrete case we get |
| 5520 | * a few fun cases generally called infeasible weight scenarios. |
| 5521 | * |
| 5522 | * [XXX expand on: |
| 5523 | * - infeasible weights; |
| 5524 | * - local vs global optima in the discrete case. ] |
| 5525 | * |
| 5526 | * |
| 5527 | * SCHED DOMAINS |
| 5528 | * |
| 5529 | * In order to solve the imbalance equation (4), and avoid the obvious O(n^2) |
| 5530 | * for all i,j solution, we create a tree of cpus that follows the hardware |
| 5531 | * topology where each level pairs two lower groups (or better). This results |
| 5532 | * in O(log n) layers. Furthermore we reduce the number of cpus going up the |
| 5533 | * tree to only the first of the previous level and we decrease the frequency |
| 5534 | * of load-balance at each level inv. proportional to the number of cpus in |
| 5535 | * the groups. |
| 5536 | * |
| 5537 | * This yields: |
| 5538 | * |
| 5539 | * log_2 n 1 n |
| 5540 | * \Sum { --- * --- * 2^i } = O(n) (5) |
| 5541 | * i = 0 2^i 2^i |
| 5542 | * `- size of each group |
| 5543 | * | | `- number of cpus doing load-balance |
| 5544 | * | `- freq |
| 5545 | * `- sum over all levels |
| 5546 | * |
| 5547 | * Coupled with a limit on how many tasks we can migrate every balance pass, |
| 5548 | * this makes (5) the runtime complexity of the balancer. |
| 5549 | * |
| 5550 | * An important property here is that each CPU is still (indirectly) connected |
| 5551 | * to every other cpu in at most O(log n) steps: |
| 5552 | * |
| 5553 | * The adjacency matrix of the resulting graph is given by: |
| 5554 | * |
| 5555 | * log_2 n |
| 5556 | * A_i,j = \Union (i % 2^k == 0) && i / 2^(k+1) == j / 2^(k+1) (6) |
| 5557 | * k = 0 |
| 5558 | * |
| 5559 | * And you'll find that: |
| 5560 | * |
| 5561 | * A^(log_2 n)_i,j != 0 for all i,j (7) |
| 5562 | * |
| 5563 | * Showing there's indeed a path between every cpu in at most O(log n) steps. |
| 5564 | * The task movement gives a factor of O(m), giving a convergence complexity |
| 5565 | * of: |
| 5566 | * |
| 5567 | * O(nm log n), n := nr_cpus, m := nr_tasks (8) |
| 5568 | * |
| 5569 | * |
| 5570 | * WORK CONSERVING |
| 5571 | * |
| 5572 | * In order to avoid CPUs going idle while there's still work to do, new idle |
| 5573 | * balancing is more aggressive and has the newly idle cpu iterate up the domain |
| 5574 | * tree itself instead of relying on other CPUs to bring it work. |
| 5575 | * |
| 5576 | * This adds some complexity to both (5) and (8) but it reduces the total idle |
| 5577 | * time. |
| 5578 | * |
| 5579 | * [XXX more?] |
| 5580 | * |
| 5581 | * |
| 5582 | * CGROUPS |
| 5583 | * |
| 5584 | * Cgroups make a horror show out of (2), instead of a simple sum we get: |
| 5585 | * |
| 5586 | * s_k,i |
| 5587 | * W_i,0 = \Sum_j \Prod_k w_k * ----- (9) |
| 5588 | * S_k |
| 5589 | * |
| 5590 | * Where |
| 5591 | * |
| 5592 | * s_k,i = \Sum_j w_i,j,k and S_k = \Sum_i s_k,i (10) |
| 5593 | * |
| 5594 | * w_i,j,k is the weight of the j-th runnable task in the k-th cgroup on cpu i. |
| 5595 | * |
| 5596 | * The big problem is S_k, its a global sum needed to compute a local (W_i) |
| 5597 | * property. |
| 5598 | * |
| 5599 | * [XXX write more on how we solve this.. _after_ merging pjt's patches that |
| 5600 | * rewrite all of this once again.] |
| 5601 | */ |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 5602 | |
Hiroshi Shimamoto | ed387b7 | 2012-01-31 11:40:32 +0900 | [diff] [blame] | 5603 | static unsigned long __read_mostly max_load_balance_interval = HZ/10; |
| 5604 | |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 5605 | enum fbq_type { regular, remote, all }; |
| 5606 | |
Peter Zijlstra | ddcdf6e | 2012-02-22 19:27:40 +0100 | [diff] [blame] | 5607 | #define LBF_ALL_PINNED 0x01 |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5608 | #define LBF_NEED_BREAK 0x02 |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 5609 | #define LBF_DST_PINNED 0x04 |
| 5610 | #define LBF_SOME_PINNED 0x08 |
Peter Zijlstra | ddcdf6e | 2012-02-22 19:27:40 +0100 | [diff] [blame] | 5611 | |
| 5612 | struct lb_env { |
| 5613 | struct sched_domain *sd; |
| 5614 | |
Peter Zijlstra | ddcdf6e | 2012-02-22 19:27:40 +0100 | [diff] [blame] | 5615 | struct rq *src_rq; |
Prashanth Nageshappa | 85c1e7d | 2012-06-19 17:47:34 +0530 | [diff] [blame] | 5616 | int src_cpu; |
Peter Zijlstra | ddcdf6e | 2012-02-22 19:27:40 +0100 | [diff] [blame] | 5617 | |
| 5618 | int dst_cpu; |
| 5619 | struct rq *dst_rq; |
| 5620 | |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 5621 | struct cpumask *dst_grpmask; |
| 5622 | int new_dst_cpu; |
Peter Zijlstra | ddcdf6e | 2012-02-22 19:27:40 +0100 | [diff] [blame] | 5623 | enum cpu_idle_type idle; |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 5624 | long imbalance; |
Michael Wang | b9403130 | 2012-07-12 16:10:13 +0800 | [diff] [blame] | 5625 | /* The set of CPUs under consideration for load-balancing */ |
| 5626 | struct cpumask *cpus; |
| 5627 | |
Peter Zijlstra | ddcdf6e | 2012-02-22 19:27:40 +0100 | [diff] [blame] | 5628 | unsigned int flags; |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5629 | |
| 5630 | unsigned int loop; |
| 5631 | unsigned int loop_break; |
| 5632 | unsigned int loop_max; |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 5633 | |
| 5634 | enum fbq_type fbq_type; |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5635 | struct list_head tasks; |
Peter Zijlstra | ddcdf6e | 2012-02-22 19:27:40 +0100 | [diff] [blame] | 5636 | }; |
| 5637 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5638 | /* |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 5639 | * Is this task likely cache-hot: |
| 5640 | */ |
Hillf Danton | 5d5e2b1 | 2014-06-10 10:58:43 +0200 | [diff] [blame] | 5641 | static int task_hot(struct task_struct *p, struct lb_env *env) |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 5642 | { |
| 5643 | s64 delta; |
| 5644 | |
Kirill Tkhai | e5673f2 | 2014-08-20 13:48:01 +0400 | [diff] [blame] | 5645 | lockdep_assert_held(&env->src_rq->lock); |
| 5646 | |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 5647 | if (p->sched_class != &fair_sched_class) |
| 5648 | return 0; |
| 5649 | |
| 5650 | if (unlikely(p->policy == SCHED_IDLE)) |
| 5651 | return 0; |
| 5652 | |
| 5653 | /* |
| 5654 | * Buddy candidates are cache hot: |
| 5655 | */ |
Hillf Danton | 5d5e2b1 | 2014-06-10 10:58:43 +0200 | [diff] [blame] | 5656 | if (sched_feat(CACHE_HOT_BUDDY) && env->dst_rq->nr_running && |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 5657 | (&p->se == cfs_rq_of(&p->se)->next || |
| 5658 | &p->se == cfs_rq_of(&p->se)->last)) |
| 5659 | return 1; |
| 5660 | |
| 5661 | if (sysctl_sched_migration_cost == -1) |
| 5662 | return 1; |
| 5663 | if (sysctl_sched_migration_cost == 0) |
| 5664 | return 0; |
| 5665 | |
Hillf Danton | 5d5e2b1 | 2014-06-10 10:58:43 +0200 | [diff] [blame] | 5666 | delta = rq_clock_task(env->src_rq) - p->se.exec_start; |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 5667 | |
| 5668 | return delta < (s64)sysctl_sched_migration_cost; |
| 5669 | } |
| 5670 | |
Mel Gorman | 3a7053b | 2013-10-07 11:29:00 +0100 | [diff] [blame] | 5671 | #ifdef CONFIG_NUMA_BALANCING |
Rik van Riel | c1ceac6 | 2015-05-14 22:59:36 -0400 | [diff] [blame] | 5672 | /* |
| 5673 | * Returns true if the destination node is the preferred node. |
| 5674 | * Needs to match fbq_classify_rq(): if there is a runnable task |
| 5675 | * that is not on its preferred node, we should identify it. |
| 5676 | */ |
Mel Gorman | 3a7053b | 2013-10-07 11:29:00 +0100 | [diff] [blame] | 5677 | static bool migrate_improves_locality(struct task_struct *p, struct lb_env *env) |
| 5678 | { |
Rik van Riel | b1ad065 | 2014-05-15 13:03:06 -0400 | [diff] [blame] | 5679 | struct numa_group *numa_group = rcu_dereference(p->numa_group); |
Rik van Riel | c1ceac6 | 2015-05-14 22:59:36 -0400 | [diff] [blame] | 5680 | unsigned long src_faults, dst_faults; |
Mel Gorman | 3a7053b | 2013-10-07 11:29:00 +0100 | [diff] [blame] | 5681 | int src_nid, dst_nid; |
| 5682 | |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 5683 | if (!sched_feat(NUMA_FAVOUR_HIGHER) || !p->numa_faults || |
Mel Gorman | 3a7053b | 2013-10-07 11:29:00 +0100 | [diff] [blame] | 5684 | !(env->sd->flags & SD_NUMA)) { |
| 5685 | return false; |
| 5686 | } |
| 5687 | |
| 5688 | src_nid = cpu_to_node(env->src_cpu); |
| 5689 | dst_nid = cpu_to_node(env->dst_cpu); |
| 5690 | |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 5691 | if (src_nid == dst_nid) |
Mel Gorman | 3a7053b | 2013-10-07 11:29:00 +0100 | [diff] [blame] | 5692 | return false; |
| 5693 | |
Rik van Riel | b1ad065 | 2014-05-15 13:03:06 -0400 | [diff] [blame] | 5694 | /* Encourage migration to the preferred node. */ |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 5695 | if (dst_nid == p->numa_preferred_nid) |
| 5696 | return true; |
| 5697 | |
Rik van Riel | c1ceac6 | 2015-05-14 22:59:36 -0400 | [diff] [blame] | 5698 | /* Migrating away from the preferred node is bad. */ |
| 5699 | if (src_nid == p->numa_preferred_nid) |
| 5700 | return false; |
| 5701 | |
| 5702 | if (numa_group) { |
| 5703 | src_faults = group_faults(p, src_nid); |
| 5704 | dst_faults = group_faults(p, dst_nid); |
| 5705 | } else { |
| 5706 | src_faults = task_faults(p, src_nid); |
| 5707 | dst_faults = task_faults(p, dst_nid); |
| 5708 | } |
| 5709 | |
| 5710 | return dst_faults > src_faults; |
Mel Gorman | 3a7053b | 2013-10-07 11:29:00 +0100 | [diff] [blame] | 5711 | } |
Mel Gorman | 7a0f308 | 2013-10-07 11:29:01 +0100 | [diff] [blame] | 5712 | |
| 5713 | |
| 5714 | static bool migrate_degrades_locality(struct task_struct *p, struct lb_env *env) |
| 5715 | { |
Rik van Riel | b1ad065 | 2014-05-15 13:03:06 -0400 | [diff] [blame] | 5716 | struct numa_group *numa_group = rcu_dereference(p->numa_group); |
Rik van Riel | c1ceac6 | 2015-05-14 22:59:36 -0400 | [diff] [blame] | 5717 | unsigned long src_faults, dst_faults; |
Mel Gorman | 7a0f308 | 2013-10-07 11:29:01 +0100 | [diff] [blame] | 5718 | int src_nid, dst_nid; |
| 5719 | |
| 5720 | if (!sched_feat(NUMA) || !sched_feat(NUMA_RESIST_LOWER)) |
| 5721 | return false; |
| 5722 | |
Iulia Manda | 44dba3d | 2014-10-31 02:13:31 +0200 | [diff] [blame] | 5723 | if (!p->numa_faults || !(env->sd->flags & SD_NUMA)) |
Mel Gorman | 7a0f308 | 2013-10-07 11:29:01 +0100 | [diff] [blame] | 5724 | return false; |
| 5725 | |
| 5726 | src_nid = cpu_to_node(env->src_cpu); |
| 5727 | dst_nid = cpu_to_node(env->dst_cpu); |
| 5728 | |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 5729 | if (src_nid == dst_nid) |
Mel Gorman | 7a0f308 | 2013-10-07 11:29:01 +0100 | [diff] [blame] | 5730 | return false; |
| 5731 | |
Rik van Riel | c1ceac6 | 2015-05-14 22:59:36 -0400 | [diff] [blame] | 5732 | /* Migrating away from the preferred node is bad. */ |
Mel Gorman | 83e1d2c | 2013-10-07 11:29:27 +0100 | [diff] [blame] | 5733 | if (src_nid == p->numa_preferred_nid) |
| 5734 | return true; |
| 5735 | |
Rik van Riel | c1ceac6 | 2015-05-14 22:59:36 -0400 | [diff] [blame] | 5736 | /* Encourage migration to the preferred node. */ |
| 5737 | if (dst_nid == p->numa_preferred_nid) |
| 5738 | return false; |
| 5739 | |
| 5740 | if (numa_group) { |
| 5741 | src_faults = group_faults(p, src_nid); |
| 5742 | dst_faults = group_faults(p, dst_nid); |
| 5743 | } else { |
| 5744 | src_faults = task_faults(p, src_nid); |
| 5745 | dst_faults = task_faults(p, dst_nid); |
| 5746 | } |
| 5747 | |
| 5748 | return dst_faults < src_faults; |
Mel Gorman | 7a0f308 | 2013-10-07 11:29:01 +0100 | [diff] [blame] | 5749 | } |
| 5750 | |
Mel Gorman | 3a7053b | 2013-10-07 11:29:00 +0100 | [diff] [blame] | 5751 | #else |
| 5752 | static inline bool migrate_improves_locality(struct task_struct *p, |
| 5753 | struct lb_env *env) |
| 5754 | { |
| 5755 | return false; |
| 5756 | } |
Mel Gorman | 7a0f308 | 2013-10-07 11:29:01 +0100 | [diff] [blame] | 5757 | |
| 5758 | static inline bool migrate_degrades_locality(struct task_struct *p, |
| 5759 | struct lb_env *env) |
| 5760 | { |
| 5761 | return false; |
| 5762 | } |
Mel Gorman | 3a7053b | 2013-10-07 11:29:00 +0100 | [diff] [blame] | 5763 | #endif |
| 5764 | |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 5765 | /* |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5766 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? |
| 5767 | */ |
| 5768 | static |
Peter Zijlstra | 8e45cb5 | 2012-02-22 12:47:19 +0100 | [diff] [blame] | 5769 | int can_migrate_task(struct task_struct *p, struct lb_env *env) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5770 | { |
| 5771 | int tsk_cache_hot = 0; |
Kirill Tkhai | e5673f2 | 2014-08-20 13:48:01 +0400 | [diff] [blame] | 5772 | |
| 5773 | lockdep_assert_held(&env->src_rq->lock); |
| 5774 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5775 | /* |
| 5776 | * We do not migrate tasks that are: |
Joonsoo Kim | d319808 | 2013-04-23 17:27:40 +0900 | [diff] [blame] | 5777 | * 1) throttled_lb_pair, or |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5778 | * 2) cannot be migrated to this CPU due to cpus_allowed, or |
Joonsoo Kim | d319808 | 2013-04-23 17:27:40 +0900 | [diff] [blame] | 5779 | * 3) running (obviously), or |
| 5780 | * 4) are cache-hot on their current CPU. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5781 | */ |
Joonsoo Kim | d319808 | 2013-04-23 17:27:40 +0900 | [diff] [blame] | 5782 | if (throttled_lb_pair(task_group(p), env->src_cpu, env->dst_cpu)) |
| 5783 | return 0; |
| 5784 | |
Peter Zijlstra | ddcdf6e | 2012-02-22 19:27:40 +0100 | [diff] [blame] | 5785 | if (!cpumask_test_cpu(env->dst_cpu, tsk_cpus_allowed(p))) { |
Joonsoo Kim | e02e60c | 2013-04-23 17:27:42 +0900 | [diff] [blame] | 5786 | int cpu; |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 5787 | |
Lucas De Marchi | 41acab8 | 2010-03-10 23:37:45 -0300 | [diff] [blame] | 5788 | schedstat_inc(p, se.statistics.nr_failed_migrations_affine); |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 5789 | |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 5790 | env->flags |= LBF_SOME_PINNED; |
| 5791 | |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 5792 | /* |
| 5793 | * Remember if this task can be migrated to any other cpu in |
| 5794 | * our sched_group. We may want to revisit it if we couldn't |
| 5795 | * meet load balance goals by pulling other tasks on src_cpu. |
| 5796 | * |
| 5797 | * Also avoid computing new_dst_cpu if we have already computed |
| 5798 | * one in current iteration. |
| 5799 | */ |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 5800 | if (!env->dst_grpmask || (env->flags & LBF_DST_PINNED)) |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 5801 | return 0; |
| 5802 | |
Joonsoo Kim | e02e60c | 2013-04-23 17:27:42 +0900 | [diff] [blame] | 5803 | /* Prevent to re-select dst_cpu via env's cpus */ |
| 5804 | for_each_cpu_and(cpu, env->dst_grpmask, env->cpus) { |
| 5805 | if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) { |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 5806 | env->flags |= LBF_DST_PINNED; |
Joonsoo Kim | e02e60c | 2013-04-23 17:27:42 +0900 | [diff] [blame] | 5807 | env->new_dst_cpu = cpu; |
| 5808 | break; |
| 5809 | } |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 5810 | } |
Joonsoo Kim | e02e60c | 2013-04-23 17:27:42 +0900 | [diff] [blame] | 5811 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5812 | return 0; |
| 5813 | } |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 5814 | |
| 5815 | /* Record that we found atleast one task that could run on dst_cpu */ |
Peter Zijlstra | 8e45cb5 | 2012-02-22 12:47:19 +0100 | [diff] [blame] | 5816 | env->flags &= ~LBF_ALL_PINNED; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5817 | |
Peter Zijlstra | ddcdf6e | 2012-02-22 19:27:40 +0100 | [diff] [blame] | 5818 | if (task_running(env->src_rq, p)) { |
Lucas De Marchi | 41acab8 | 2010-03-10 23:37:45 -0300 | [diff] [blame] | 5819 | schedstat_inc(p, se.statistics.nr_failed_migrations_running); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5820 | return 0; |
| 5821 | } |
| 5822 | |
| 5823 | /* |
| 5824 | * Aggressive migration if: |
Mel Gorman | 3a7053b | 2013-10-07 11:29:00 +0100 | [diff] [blame] | 5825 | * 1) destination numa is preferred |
| 5826 | * 2) task is cache cold, or |
| 5827 | * 3) too many balance attempts have failed. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5828 | */ |
Hillf Danton | 5d5e2b1 | 2014-06-10 10:58:43 +0200 | [diff] [blame] | 5829 | tsk_cache_hot = task_hot(p, env); |
Mel Gorman | 7a0f308 | 2013-10-07 11:29:01 +0100 | [diff] [blame] | 5830 | if (!tsk_cache_hot) |
| 5831 | tsk_cache_hot = migrate_degrades_locality(p, env); |
Mel Gorman | 3a7053b | 2013-10-07 11:29:00 +0100 | [diff] [blame] | 5832 | |
Kirill Tkhai | 7a96c23 | 2014-09-22 22:36:12 +0400 | [diff] [blame] | 5833 | if (migrate_improves_locality(p, env) || !tsk_cache_hot || |
| 5834 | env->sd->nr_balance_failed > env->sd->cache_nice_tries) { |
Mel Gorman | 3a7053b | 2013-10-07 11:29:00 +0100 | [diff] [blame] | 5835 | if (tsk_cache_hot) { |
| 5836 | schedstat_inc(env->sd, lb_hot_gained[env->idle]); |
| 5837 | schedstat_inc(p, se.statistics.nr_forced_migrations); |
| 5838 | } |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5839 | return 1; |
| 5840 | } |
| 5841 | |
Zhang Hang | 4e2dcb7 | 2013-04-10 14:04:55 +0800 | [diff] [blame] | 5842 | schedstat_inc(p, se.statistics.nr_failed_migrations_hot); |
| 5843 | return 0; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5844 | } |
| 5845 | |
Peter Zijlstra | 897c395 | 2009-12-17 17:45:42 +0100 | [diff] [blame] | 5846 | /* |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5847 | * detach_task() -- detach the task for the migration specified in env |
Peter Zijlstra | 897c395 | 2009-12-17 17:45:42 +0100 | [diff] [blame] | 5848 | */ |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5849 | static void detach_task(struct task_struct *p, struct lb_env *env) |
| 5850 | { |
| 5851 | lockdep_assert_held(&env->src_rq->lock); |
| 5852 | |
| 5853 | deactivate_task(env->src_rq, p, 0); |
| 5854 | p->on_rq = TASK_ON_RQ_MIGRATING; |
| 5855 | set_task_cpu(p, env->dst_cpu); |
| 5856 | } |
| 5857 | |
| 5858 | /* |
Kirill Tkhai | e5673f2 | 2014-08-20 13:48:01 +0400 | [diff] [blame] | 5859 | * detach_one_task() -- tries to dequeue exactly one task from env->src_rq, as |
Peter Zijlstra | 897c395 | 2009-12-17 17:45:42 +0100 | [diff] [blame] | 5860 | * part of active balancing operations within "domain". |
Peter Zijlstra | 897c395 | 2009-12-17 17:45:42 +0100 | [diff] [blame] | 5861 | * |
Kirill Tkhai | e5673f2 | 2014-08-20 13:48:01 +0400 | [diff] [blame] | 5862 | * Returns a task if successful and NULL otherwise. |
Peter Zijlstra | 897c395 | 2009-12-17 17:45:42 +0100 | [diff] [blame] | 5863 | */ |
Kirill Tkhai | e5673f2 | 2014-08-20 13:48:01 +0400 | [diff] [blame] | 5864 | static struct task_struct *detach_one_task(struct lb_env *env) |
Peter Zijlstra | 897c395 | 2009-12-17 17:45:42 +0100 | [diff] [blame] | 5865 | { |
| 5866 | struct task_struct *p, *n; |
Peter Zijlstra | 897c395 | 2009-12-17 17:45:42 +0100 | [diff] [blame] | 5867 | |
Kirill Tkhai | e5673f2 | 2014-08-20 13:48:01 +0400 | [diff] [blame] | 5868 | lockdep_assert_held(&env->src_rq->lock); |
| 5869 | |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5870 | list_for_each_entry_safe(p, n, &env->src_rq->cfs_tasks, se.group_node) { |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5871 | if (!can_migrate_task(p, env)) |
| 5872 | continue; |
Peter Zijlstra | 897c395 | 2009-12-17 17:45:42 +0100 | [diff] [blame] | 5873 | |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5874 | detach_task(p, env); |
Kirill Tkhai | e5673f2 | 2014-08-20 13:48:01 +0400 | [diff] [blame] | 5875 | |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5876 | /* |
Kirill Tkhai | e5673f2 | 2014-08-20 13:48:01 +0400 | [diff] [blame] | 5877 | * Right now, this is only the second place where |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5878 | * lb_gained[env->idle] is updated (other is detach_tasks) |
Kirill Tkhai | e5673f2 | 2014-08-20 13:48:01 +0400 | [diff] [blame] | 5879 | * so we can safely collect stats here rather than |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5880 | * inside detach_tasks(). |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5881 | */ |
| 5882 | schedstat_inc(env->sd, lb_gained[env->idle]); |
Kirill Tkhai | e5673f2 | 2014-08-20 13:48:01 +0400 | [diff] [blame] | 5883 | return p; |
Peter Zijlstra | 897c395 | 2009-12-17 17:45:42 +0100 | [diff] [blame] | 5884 | } |
Kirill Tkhai | e5673f2 | 2014-08-20 13:48:01 +0400 | [diff] [blame] | 5885 | return NULL; |
Peter Zijlstra | 897c395 | 2009-12-17 17:45:42 +0100 | [diff] [blame] | 5886 | } |
| 5887 | |
Peter Zijlstra | eb95308 | 2012-04-17 13:38:40 +0200 | [diff] [blame] | 5888 | static const unsigned int sched_nr_migrate_break = 32; |
| 5889 | |
Peter Zijlstra | 5d6523e | 2012-03-10 00:07:36 +0100 | [diff] [blame] | 5890 | /* |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5891 | * detach_tasks() -- tries to detach up to imbalance weighted load from |
| 5892 | * busiest_rq, as part of a balancing operation within domain "sd". |
Peter Zijlstra | 5d6523e | 2012-03-10 00:07:36 +0100 | [diff] [blame] | 5893 | * |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5894 | * Returns number of detached tasks if successful and 0 otherwise. |
Peter Zijlstra | 5d6523e | 2012-03-10 00:07:36 +0100 | [diff] [blame] | 5895 | */ |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5896 | static int detach_tasks(struct lb_env *env) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5897 | { |
Peter Zijlstra | 5d6523e | 2012-03-10 00:07:36 +0100 | [diff] [blame] | 5898 | struct list_head *tasks = &env->src_rq->cfs_tasks; |
| 5899 | struct task_struct *p; |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5900 | unsigned long load; |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5901 | int detached = 0; |
| 5902 | |
| 5903 | lockdep_assert_held(&env->src_rq->lock); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5904 | |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 5905 | if (env->imbalance <= 0) |
Peter Zijlstra | 5d6523e | 2012-03-10 00:07:36 +0100 | [diff] [blame] | 5906 | return 0; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5907 | |
Peter Zijlstra | 5d6523e | 2012-03-10 00:07:36 +0100 | [diff] [blame] | 5908 | while (!list_empty(tasks)) { |
| 5909 | p = list_first_entry(tasks, struct task_struct, se.group_node); |
| 5910 | |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5911 | env->loop++; |
| 5912 | /* We've more or less seen every task there is, call it quits */ |
Peter Zijlstra | 5d6523e | 2012-03-10 00:07:36 +0100 | [diff] [blame] | 5913 | if (env->loop > env->loop_max) |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5914 | break; |
Peter Zijlstra | 5d6523e | 2012-03-10 00:07:36 +0100 | [diff] [blame] | 5915 | |
| 5916 | /* take a breather every nr_migrate tasks */ |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5917 | if (env->loop > env->loop_break) { |
Peter Zijlstra | eb95308 | 2012-04-17 13:38:40 +0200 | [diff] [blame] | 5918 | env->loop_break += sched_nr_migrate_break; |
Peter Zijlstra | 8e45cb5 | 2012-02-22 12:47:19 +0100 | [diff] [blame] | 5919 | env->flags |= LBF_NEED_BREAK; |
Peter Zijlstra | ee00e66 | 2009-12-17 17:25:20 +0100 | [diff] [blame] | 5920 | break; |
Peter Zijlstra | a195f00 | 2011-09-22 15:30:18 +0200 | [diff] [blame] | 5921 | } |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5922 | |
Joonsoo Kim | d319808 | 2013-04-23 17:27:40 +0900 | [diff] [blame] | 5923 | if (!can_migrate_task(p, env)) |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5924 | goto next; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5925 | |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5926 | load = task_h_load(p); |
Peter Zijlstra | 5d6523e | 2012-03-10 00:07:36 +0100 | [diff] [blame] | 5927 | |
Peter Zijlstra | eb95308 | 2012-04-17 13:38:40 +0200 | [diff] [blame] | 5928 | if (sched_feat(LB_MIN) && load < 16 && !env->sd->nr_balance_failed) |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5929 | goto next; |
| 5930 | |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 5931 | if ((load / 2) > env->imbalance) |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5932 | goto next; |
| 5933 | |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5934 | detach_task(p, env); |
| 5935 | list_add(&p->se.group_node, &env->tasks); |
| 5936 | |
| 5937 | detached++; |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 5938 | env->imbalance -= load; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5939 | |
| 5940 | #ifdef CONFIG_PREEMPT |
Peter Zijlstra | ee00e66 | 2009-12-17 17:25:20 +0100 | [diff] [blame] | 5941 | /* |
| 5942 | * NEWIDLE balancing is a source of latency, so preemptible |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5943 | * kernels will stop after the first task is detached to minimize |
Peter Zijlstra | ee00e66 | 2009-12-17 17:25:20 +0100 | [diff] [blame] | 5944 | * the critical section. |
| 5945 | */ |
Peter Zijlstra | 5d6523e | 2012-03-10 00:07:36 +0100 | [diff] [blame] | 5946 | if (env->idle == CPU_NEWLY_IDLE) |
Peter Zijlstra | ee00e66 | 2009-12-17 17:25:20 +0100 | [diff] [blame] | 5947 | break; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5948 | #endif |
| 5949 | |
Peter Zijlstra | ee00e66 | 2009-12-17 17:25:20 +0100 | [diff] [blame] | 5950 | /* |
| 5951 | * We only want to steal up to the prescribed amount of |
| 5952 | * weighted load. |
| 5953 | */ |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 5954 | if (env->imbalance <= 0) |
Peter Zijlstra | ee00e66 | 2009-12-17 17:25:20 +0100 | [diff] [blame] | 5955 | break; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5956 | |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 5957 | continue; |
| 5958 | next: |
Peter Zijlstra | 5d6523e | 2012-03-10 00:07:36 +0100 | [diff] [blame] | 5959 | list_move_tail(&p->se.group_node, tasks); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5960 | } |
Peter Zijlstra | 5d6523e | 2012-03-10 00:07:36 +0100 | [diff] [blame] | 5961 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5962 | /* |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5963 | * Right now, this is one of only two places we collect this stat |
| 5964 | * so we can safely collect detach_one_task() stats here rather |
| 5965 | * than inside detach_one_task(). |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5966 | */ |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5967 | schedstat_add(env->sd, lb_gained[env->idle], detached); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 5968 | |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 5969 | return detached; |
| 5970 | } |
| 5971 | |
| 5972 | /* |
| 5973 | * attach_task() -- attach the task detached by detach_task() to its new rq. |
| 5974 | */ |
| 5975 | static void attach_task(struct rq *rq, struct task_struct *p) |
| 5976 | { |
| 5977 | lockdep_assert_held(&rq->lock); |
| 5978 | |
| 5979 | BUG_ON(task_rq(p) != rq); |
| 5980 | p->on_rq = TASK_ON_RQ_QUEUED; |
| 5981 | activate_task(rq, p, 0); |
| 5982 | check_preempt_curr(rq, p, 0); |
| 5983 | } |
| 5984 | |
| 5985 | /* |
| 5986 | * attach_one_task() -- attaches the task returned from detach_one_task() to |
| 5987 | * its new rq. |
| 5988 | */ |
| 5989 | static void attach_one_task(struct rq *rq, struct task_struct *p) |
| 5990 | { |
| 5991 | raw_spin_lock(&rq->lock); |
| 5992 | attach_task(rq, p); |
| 5993 | raw_spin_unlock(&rq->lock); |
| 5994 | } |
| 5995 | |
| 5996 | /* |
| 5997 | * attach_tasks() -- attaches all tasks detached by detach_tasks() to their |
| 5998 | * new rq. |
| 5999 | */ |
| 6000 | static void attach_tasks(struct lb_env *env) |
| 6001 | { |
| 6002 | struct list_head *tasks = &env->tasks; |
| 6003 | struct task_struct *p; |
| 6004 | |
| 6005 | raw_spin_lock(&env->dst_rq->lock); |
| 6006 | |
| 6007 | while (!list_empty(tasks)) { |
| 6008 | p = list_first_entry(tasks, struct task_struct, se.group_node); |
| 6009 | list_del_init(&p->se.group_node); |
| 6010 | |
| 6011 | attach_task(env->dst_rq, p); |
| 6012 | } |
| 6013 | |
| 6014 | raw_spin_unlock(&env->dst_rq->lock); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6015 | } |
| 6016 | |
Peter Zijlstra | 230059de | 2009-12-17 17:47:12 +0100 | [diff] [blame] | 6017 | #ifdef CONFIG_FAIR_GROUP_SCHED |
Peter Zijlstra | 9e3081c | 2010-11-15 15:47:02 -0800 | [diff] [blame] | 6018 | /* |
| 6019 | * update tg->load_weight by folding this cpu's load_avg |
| 6020 | */ |
Paul Turner | 48a1675 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 6021 | static void __update_blocked_averages_cpu(struct task_group *tg, int cpu) |
Peter Zijlstra | 9e3081c | 2010-11-15 15:47:02 -0800 | [diff] [blame] | 6022 | { |
Paul Turner | 48a1675 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 6023 | struct sched_entity *se = tg->se[cpu]; |
| 6024 | struct cfs_rq *cfs_rq = tg->cfs_rq[cpu]; |
Peter Zijlstra | 9e3081c | 2010-11-15 15:47:02 -0800 | [diff] [blame] | 6025 | |
Paul Turner | 48a1675 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 6026 | /* throttled entities do not contribute to load */ |
| 6027 | if (throttled_hierarchy(cfs_rq)) |
| 6028 | return; |
Peter Zijlstra | 9e3081c | 2010-11-15 15:47:02 -0800 | [diff] [blame] | 6029 | |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 6030 | update_cfs_rq_blocked_load(cfs_rq, 1); |
Peter Zijlstra | 9e3081c | 2010-11-15 15:47:02 -0800 | [diff] [blame] | 6031 | |
Paul Turner | 8295836 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 6032 | if (se) { |
| 6033 | update_entity_load_avg(se, 1); |
| 6034 | /* |
| 6035 | * We pivot on our runnable average having decayed to zero for |
| 6036 | * list removal. This generally implies that all our children |
| 6037 | * have also been removed (modulo rounding error or bandwidth |
| 6038 | * control); however, such cases are rare and we can fix these |
| 6039 | * at enqueue. |
| 6040 | * |
| 6041 | * TODO: fix up out-of-order children on enqueue. |
| 6042 | */ |
| 6043 | if (!se->avg.runnable_avg_sum && !cfs_rq->nr_running) |
| 6044 | list_del_leaf_cfs_rq(cfs_rq); |
| 6045 | } else { |
Paul Turner | 48a1675 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 6046 | struct rq *rq = rq_of(cfs_rq); |
Paul Turner | 8295836 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 6047 | update_rq_runnable_avg(rq, rq->nr_running); |
| 6048 | } |
Peter Zijlstra | 9e3081c | 2010-11-15 15:47:02 -0800 | [diff] [blame] | 6049 | } |
| 6050 | |
Paul Turner | 48a1675 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 6051 | static void update_blocked_averages(int cpu) |
Peter Zijlstra | 9e3081c | 2010-11-15 15:47:02 -0800 | [diff] [blame] | 6052 | { |
Peter Zijlstra | 9e3081c | 2010-11-15 15:47:02 -0800 | [diff] [blame] | 6053 | struct rq *rq = cpu_rq(cpu); |
Paul Turner | 48a1675 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 6054 | struct cfs_rq *cfs_rq; |
| 6055 | unsigned long flags; |
Peter Zijlstra | 9e3081c | 2010-11-15 15:47:02 -0800 | [diff] [blame] | 6056 | |
Paul Turner | 48a1675 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 6057 | raw_spin_lock_irqsave(&rq->lock, flags); |
| 6058 | update_rq_clock(rq); |
Peter Zijlstra | 9763b67 | 2011-07-13 13:09:25 +0200 | [diff] [blame] | 6059 | /* |
| 6060 | * Iterates the task_group tree in a bottom up fashion, see |
| 6061 | * list_add_leaf_cfs_rq() for details. |
| 6062 | */ |
Paul Turner | 64660c8 | 2011-07-21 09:43:36 -0700 | [diff] [blame] | 6063 | for_each_leaf_cfs_rq(rq, cfs_rq) { |
Paul Turner | 48a1675 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 6064 | /* |
| 6065 | * Note: We may want to consider periodically releasing |
| 6066 | * rq->lock about these updates so that creating many task |
| 6067 | * groups does not result in continually extending hold time. |
| 6068 | */ |
| 6069 | __update_blocked_averages_cpu(cfs_rq->tg, rq->cpu); |
Paul Turner | 64660c8 | 2011-07-21 09:43:36 -0700 | [diff] [blame] | 6070 | } |
Paul Turner | 48a1675 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 6071 | |
| 6072 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
Peter Zijlstra | 9e3081c | 2010-11-15 15:47:02 -0800 | [diff] [blame] | 6073 | } |
| 6074 | |
Peter Zijlstra | 9763b67 | 2011-07-13 13:09:25 +0200 | [diff] [blame] | 6075 | /* |
Vladimir Davydov | 6852079 | 2013-07-15 17:49:19 +0400 | [diff] [blame] | 6076 | * Compute the hierarchical load factor for cfs_rq and all its ascendants. |
Peter Zijlstra | 9763b67 | 2011-07-13 13:09:25 +0200 | [diff] [blame] | 6077 | * This needs to be done in a top-down fashion because the load of a child |
| 6078 | * group is a fraction of its parents load. |
| 6079 | */ |
Vladimir Davydov | 6852079 | 2013-07-15 17:49:19 +0400 | [diff] [blame] | 6080 | static void update_cfs_rq_h_load(struct cfs_rq *cfs_rq) |
Peter Zijlstra | 9763b67 | 2011-07-13 13:09:25 +0200 | [diff] [blame] | 6081 | { |
Vladimir Davydov | 6852079 | 2013-07-15 17:49:19 +0400 | [diff] [blame] | 6082 | struct rq *rq = rq_of(cfs_rq); |
| 6083 | struct sched_entity *se = cfs_rq->tg->se[cpu_of(rq)]; |
Peter Zijlstra | a35b646 | 2012-08-08 21:46:40 +0200 | [diff] [blame] | 6084 | unsigned long now = jiffies; |
Vladimir Davydov | 6852079 | 2013-07-15 17:49:19 +0400 | [diff] [blame] | 6085 | unsigned long load; |
Peter Zijlstra | a35b646 | 2012-08-08 21:46:40 +0200 | [diff] [blame] | 6086 | |
Vladimir Davydov | 6852079 | 2013-07-15 17:49:19 +0400 | [diff] [blame] | 6087 | if (cfs_rq->last_h_load_update == now) |
Peter Zijlstra | a35b646 | 2012-08-08 21:46:40 +0200 | [diff] [blame] | 6088 | return; |
| 6089 | |
Vladimir Davydov | 6852079 | 2013-07-15 17:49:19 +0400 | [diff] [blame] | 6090 | cfs_rq->h_load_next = NULL; |
| 6091 | for_each_sched_entity(se) { |
| 6092 | cfs_rq = cfs_rq_of(se); |
| 6093 | cfs_rq->h_load_next = se; |
| 6094 | if (cfs_rq->last_h_load_update == now) |
| 6095 | break; |
| 6096 | } |
Peter Zijlstra | a35b646 | 2012-08-08 21:46:40 +0200 | [diff] [blame] | 6097 | |
Vladimir Davydov | 6852079 | 2013-07-15 17:49:19 +0400 | [diff] [blame] | 6098 | if (!se) { |
Vladimir Davydov | 7e3115e | 2013-09-14 19:39:46 +0400 | [diff] [blame] | 6099 | cfs_rq->h_load = cfs_rq->runnable_load_avg; |
Vladimir Davydov | 6852079 | 2013-07-15 17:49:19 +0400 | [diff] [blame] | 6100 | cfs_rq->last_h_load_update = now; |
| 6101 | } |
| 6102 | |
| 6103 | while ((se = cfs_rq->h_load_next) != NULL) { |
| 6104 | load = cfs_rq->h_load; |
| 6105 | load = div64_ul(load * se->avg.load_avg_contrib, |
| 6106 | cfs_rq->runnable_load_avg + 1); |
| 6107 | cfs_rq = group_cfs_rq(se); |
| 6108 | cfs_rq->h_load = load; |
| 6109 | cfs_rq->last_h_load_update = now; |
| 6110 | } |
Peter Zijlstra | 9763b67 | 2011-07-13 13:09:25 +0200 | [diff] [blame] | 6111 | } |
| 6112 | |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 6113 | static unsigned long task_h_load(struct task_struct *p) |
Peter Zijlstra | 230059de | 2009-12-17 17:47:12 +0100 | [diff] [blame] | 6114 | { |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 6115 | struct cfs_rq *cfs_rq = task_cfs_rq(p); |
Peter Zijlstra | 230059de | 2009-12-17 17:47:12 +0100 | [diff] [blame] | 6116 | |
Vladimir Davydov | 6852079 | 2013-07-15 17:49:19 +0400 | [diff] [blame] | 6117 | update_cfs_rq_h_load(cfs_rq); |
Alex Shi | a003a25 | 2013-06-20 10:18:51 +0800 | [diff] [blame] | 6118 | return div64_ul(p->se.avg.load_avg_contrib * cfs_rq->h_load, |
| 6119 | cfs_rq->runnable_load_avg + 1); |
Peter Zijlstra | 230059de | 2009-12-17 17:47:12 +0100 | [diff] [blame] | 6120 | } |
| 6121 | #else |
Paul Turner | 48a1675 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 6122 | static inline void update_blocked_averages(int cpu) |
Peter Zijlstra | 9e3081c | 2010-11-15 15:47:02 -0800 | [diff] [blame] | 6123 | { |
| 6124 | } |
| 6125 | |
Peter Zijlstra | 367456c | 2012-02-20 21:49:09 +0100 | [diff] [blame] | 6126 | static unsigned long task_h_load(struct task_struct *p) |
| 6127 | { |
Alex Shi | a003a25 | 2013-06-20 10:18:51 +0800 | [diff] [blame] | 6128 | return p->se.avg.load_avg_contrib; |
Peter Zijlstra | 230059de | 2009-12-17 17:47:12 +0100 | [diff] [blame] | 6129 | } |
| 6130 | #endif |
| 6131 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6132 | /********** Helpers for find_busiest_group ************************/ |
Rik van Riel | caeb178 | 2014-07-28 14:16:28 -0400 | [diff] [blame] | 6133 | |
| 6134 | enum group_type { |
| 6135 | group_other = 0, |
| 6136 | group_imbalanced, |
| 6137 | group_overloaded, |
| 6138 | }; |
| 6139 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6140 | /* |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6141 | * sg_lb_stats - stats of a sched_group required for load_balancing |
| 6142 | */ |
| 6143 | struct sg_lb_stats { |
| 6144 | unsigned long avg_load; /*Avg load across the CPUs of the group */ |
| 6145 | unsigned long group_load; /* Total load over the CPUs of the group */ |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6146 | unsigned long sum_weighted_load; /* Weighted load of group's tasks */ |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6147 | unsigned long load_per_task; |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6148 | unsigned long group_capacity; |
Vincent Guittot | 8bb5b00 | 2015-03-04 08:48:47 +0100 | [diff] [blame] | 6149 | unsigned long group_usage; /* Total usage of the group */ |
Peter Zijlstra | 147c5fc2 | 2013-08-19 15:22:57 +0200 | [diff] [blame] | 6150 | unsigned int sum_nr_running; /* Nr tasks running in the group */ |
Peter Zijlstra | 147c5fc2 | 2013-08-19 15:22:57 +0200 | [diff] [blame] | 6151 | unsigned int idle_cpus; |
| 6152 | unsigned int group_weight; |
Rik van Riel | caeb178 | 2014-07-28 14:16:28 -0400 | [diff] [blame] | 6153 | enum group_type group_type; |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6154 | int group_no_capacity; |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 6155 | #ifdef CONFIG_NUMA_BALANCING |
| 6156 | unsigned int nr_numa_running; |
| 6157 | unsigned int nr_preferred_running; |
| 6158 | #endif |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6159 | }; |
| 6160 | |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6161 | /* |
| 6162 | * sd_lb_stats - Structure to store the statistics of a sched_domain |
| 6163 | * during load balancing. |
| 6164 | */ |
| 6165 | struct sd_lb_stats { |
| 6166 | struct sched_group *busiest; /* Busiest group in this sd */ |
| 6167 | struct sched_group *local; /* Local group in this sd */ |
| 6168 | unsigned long total_load; /* Total load of all groups in sd */ |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6169 | unsigned long total_capacity; /* Total capacity of all groups in sd */ |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6170 | unsigned long avg_load; /* Average load across all groups in sd */ |
| 6171 | |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6172 | struct sg_lb_stats busiest_stat;/* Statistics of the busiest group */ |
Peter Zijlstra | 147c5fc2 | 2013-08-19 15:22:57 +0200 | [diff] [blame] | 6173 | struct sg_lb_stats local_stat; /* Statistics of the local group */ |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6174 | }; |
| 6175 | |
Peter Zijlstra | 147c5fc2 | 2013-08-19 15:22:57 +0200 | [diff] [blame] | 6176 | static inline void init_sd_lb_stats(struct sd_lb_stats *sds) |
| 6177 | { |
| 6178 | /* |
| 6179 | * Skimp on the clearing to avoid duplicate work. We can avoid clearing |
| 6180 | * local_stat because update_sg_lb_stats() does a full clear/assignment. |
| 6181 | * We must however clear busiest_stat::avg_load because |
| 6182 | * update_sd_pick_busiest() reads this before assignment. |
| 6183 | */ |
| 6184 | *sds = (struct sd_lb_stats){ |
| 6185 | .busiest = NULL, |
| 6186 | .local = NULL, |
| 6187 | .total_load = 0UL, |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6188 | .total_capacity = 0UL, |
Peter Zijlstra | 147c5fc2 | 2013-08-19 15:22:57 +0200 | [diff] [blame] | 6189 | .busiest_stat = { |
| 6190 | .avg_load = 0UL, |
Rik van Riel | caeb178 | 2014-07-28 14:16:28 -0400 | [diff] [blame] | 6191 | .sum_nr_running = 0, |
| 6192 | .group_type = group_other, |
Peter Zijlstra | 147c5fc2 | 2013-08-19 15:22:57 +0200 | [diff] [blame] | 6193 | }, |
| 6194 | }; |
| 6195 | } |
| 6196 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6197 | /** |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6198 | * get_sd_load_idx - Obtain the load index for a given sched domain. |
| 6199 | * @sd: The sched_domain whose load_idx is to be obtained. |
Kamalesh Babulal | ed1b773 | 2013-10-13 23:06:15 +0530 | [diff] [blame] | 6200 | * @idle: The idle status of the CPU for whose sd load_idx is obtained. |
Yacine Belkadi | e69f618 | 2013-07-12 20:45:47 +0200 | [diff] [blame] | 6201 | * |
| 6202 | * Return: The load index. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6203 | */ |
| 6204 | static inline int get_sd_load_idx(struct sched_domain *sd, |
| 6205 | enum cpu_idle_type idle) |
| 6206 | { |
| 6207 | int load_idx; |
| 6208 | |
| 6209 | switch (idle) { |
| 6210 | case CPU_NOT_IDLE: |
| 6211 | load_idx = sd->busy_idx; |
| 6212 | break; |
| 6213 | |
| 6214 | case CPU_NEWLY_IDLE: |
| 6215 | load_idx = sd->newidle_idx; |
| 6216 | break; |
| 6217 | default: |
| 6218 | load_idx = sd->idle_idx; |
| 6219 | break; |
| 6220 | } |
| 6221 | |
| 6222 | return load_idx; |
| 6223 | } |
| 6224 | |
Vincent Guittot | 26bc3c5 | 2014-08-26 13:06:47 +0200 | [diff] [blame] | 6225 | static unsigned long default_scale_cpu_capacity(struct sched_domain *sd, int cpu) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6226 | { |
Vincent Guittot | 26bc3c5 | 2014-08-26 13:06:47 +0200 | [diff] [blame] | 6227 | if ((sd->flags & SD_SHARE_CPUCAPACITY) && (sd->span_weight > 1)) |
| 6228 | return sd->smt_gain / sd->span_weight; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6229 | |
Vincent Guittot | 26bc3c5 | 2014-08-26 13:06:47 +0200 | [diff] [blame] | 6230 | return SCHED_CAPACITY_SCALE; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6231 | } |
| 6232 | |
Vincent Guittot | 26bc3c5 | 2014-08-26 13:06:47 +0200 | [diff] [blame] | 6233 | unsigned long __weak arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6234 | { |
Vincent Guittot | 26bc3c5 | 2014-08-26 13:06:47 +0200 | [diff] [blame] | 6235 | return default_scale_cpu_capacity(sd, cpu); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6236 | } |
| 6237 | |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 6238 | static unsigned long scale_rt_capacity(int cpu) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6239 | { |
| 6240 | struct rq *rq = cpu_rq(cpu); |
Vincent Guittot | b5b4860 | 2015-02-27 16:54:08 +0100 | [diff] [blame] | 6241 | u64 total, used, age_stamp, avg; |
Peter Zijlstra | cadefd3 | 2014-02-27 10:40:35 +0100 | [diff] [blame] | 6242 | s64 delta; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6243 | |
Peter Zijlstra | b654f7d | 2012-05-22 14:04:28 +0200 | [diff] [blame] | 6244 | /* |
| 6245 | * Since we're reading these variables without serialization make sure |
| 6246 | * we read them once before doing sanity checks on them. |
| 6247 | */ |
Jason Low | 316c1608d | 2015-04-28 13:00:20 -0700 | [diff] [blame] | 6248 | age_stamp = READ_ONCE(rq->age_stamp); |
| 6249 | avg = READ_ONCE(rq->rt_avg); |
Peter Zijlstra | cebde6d | 2015-01-05 11:18:10 +0100 | [diff] [blame] | 6250 | delta = __rq_clock_broken(rq) - age_stamp; |
Venkatesh Pallipadi | aa48380 | 2010-10-04 17:03:22 -0700 | [diff] [blame] | 6251 | |
Peter Zijlstra | cadefd3 | 2014-02-27 10:40:35 +0100 | [diff] [blame] | 6252 | if (unlikely(delta < 0)) |
| 6253 | delta = 0; |
| 6254 | |
| 6255 | total = sched_avg_period() + delta; |
Peter Zijlstra | b654f7d | 2012-05-22 14:04:28 +0200 | [diff] [blame] | 6256 | |
Vincent Guittot | b5b4860 | 2015-02-27 16:54:08 +0100 | [diff] [blame] | 6257 | used = div_u64(avg, total); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6258 | |
Vincent Guittot | b5b4860 | 2015-02-27 16:54:08 +0100 | [diff] [blame] | 6259 | if (likely(used < SCHED_CAPACITY_SCALE)) |
| 6260 | return SCHED_CAPACITY_SCALE - used; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6261 | |
Vincent Guittot | b5b4860 | 2015-02-27 16:54:08 +0100 | [diff] [blame] | 6262 | return 1; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6263 | } |
| 6264 | |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 6265 | static void update_cpu_capacity(struct sched_domain *sd, int cpu) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6266 | { |
Nicolas Pitre | ca8ce3d | 2014-05-26 18:19:39 -0400 | [diff] [blame] | 6267 | unsigned long capacity = SCHED_CAPACITY_SCALE; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6268 | struct sched_group *sdg = sd->groups; |
| 6269 | |
Vincent Guittot | 26bc3c5 | 2014-08-26 13:06:47 +0200 | [diff] [blame] | 6270 | if (sched_feat(ARCH_CAPACITY)) |
| 6271 | capacity *= arch_scale_cpu_capacity(sd, cpu); |
| 6272 | else |
| 6273 | capacity *= default_scale_cpu_capacity(sd, cpu); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6274 | |
Vincent Guittot | 26bc3c5 | 2014-08-26 13:06:47 +0200 | [diff] [blame] | 6275 | capacity >>= SCHED_CAPACITY_SHIFT; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6276 | |
Vincent Guittot | ca6d75e | 2015-02-27 16:54:09 +0100 | [diff] [blame] | 6277 | cpu_rq(cpu)->cpu_capacity_orig = capacity; |
Srivatsa Vaddagiri | 9d5efe0 | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6278 | |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 6279 | capacity *= scale_rt_capacity(cpu); |
Nicolas Pitre | ca8ce3d | 2014-05-26 18:19:39 -0400 | [diff] [blame] | 6280 | capacity >>= SCHED_CAPACITY_SHIFT; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6281 | |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 6282 | if (!capacity) |
| 6283 | capacity = 1; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6284 | |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 6285 | cpu_rq(cpu)->cpu_capacity = capacity; |
| 6286 | sdg->sgc->capacity = capacity; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6287 | } |
| 6288 | |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6289 | void update_group_capacity(struct sched_domain *sd, int cpu) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6290 | { |
| 6291 | struct sched_domain *child = sd->child; |
| 6292 | struct sched_group *group, *sdg = sd->groups; |
Vincent Guittot | dc7ff76 | 2015-03-03 11:35:03 +0100 | [diff] [blame] | 6293 | unsigned long capacity; |
Vincent Guittot | 4ec4412 | 2011-12-12 20:21:08 +0100 | [diff] [blame] | 6294 | unsigned long interval; |
| 6295 | |
| 6296 | interval = msecs_to_jiffies(sd->balance_interval); |
| 6297 | interval = clamp(interval, 1UL, max_load_balance_interval); |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6298 | sdg->sgc->next_update = jiffies + interval; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6299 | |
| 6300 | if (!child) { |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 6301 | update_cpu_capacity(sd, cpu); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6302 | return; |
| 6303 | } |
| 6304 | |
Vincent Guittot | dc7ff76 | 2015-03-03 11:35:03 +0100 | [diff] [blame] | 6305 | capacity = 0; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6306 | |
Peter Zijlstra | 74a5ce2 | 2012-05-23 18:00:43 +0200 | [diff] [blame] | 6307 | if (child->flags & SD_OVERLAP) { |
| 6308 | /* |
| 6309 | * SD_OVERLAP domains cannot assume that child groups |
| 6310 | * span the current group. |
| 6311 | */ |
| 6312 | |
Peter Zijlstra | 863bffc | 2013-08-28 11:44:39 +0200 | [diff] [blame] | 6313 | for_each_cpu(cpu, sched_group_cpus(sdg)) { |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6314 | struct sched_group_capacity *sgc; |
Srikar Dronamraju | 9abf24d | 2013-11-12 22:11:26 +0530 | [diff] [blame] | 6315 | struct rq *rq = cpu_rq(cpu); |
Peter Zijlstra | 863bffc | 2013-08-28 11:44:39 +0200 | [diff] [blame] | 6316 | |
Srikar Dronamraju | 9abf24d | 2013-11-12 22:11:26 +0530 | [diff] [blame] | 6317 | /* |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6318 | * build_sched_domains() -> init_sched_groups_capacity() |
Srikar Dronamraju | 9abf24d | 2013-11-12 22:11:26 +0530 | [diff] [blame] | 6319 | * gets here before we've attached the domains to the |
| 6320 | * runqueues. |
| 6321 | * |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 6322 | * Use capacity_of(), which is set irrespective of domains |
| 6323 | * in update_cpu_capacity(). |
Srikar Dronamraju | 9abf24d | 2013-11-12 22:11:26 +0530 | [diff] [blame] | 6324 | * |
Vincent Guittot | dc7ff76 | 2015-03-03 11:35:03 +0100 | [diff] [blame] | 6325 | * This avoids capacity from being 0 and |
Srikar Dronamraju | 9abf24d | 2013-11-12 22:11:26 +0530 | [diff] [blame] | 6326 | * causing divide-by-zero issues on boot. |
Srikar Dronamraju | 9abf24d | 2013-11-12 22:11:26 +0530 | [diff] [blame] | 6327 | */ |
| 6328 | if (unlikely(!rq->sd)) { |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 6329 | capacity += capacity_of(cpu); |
Srikar Dronamraju | 9abf24d | 2013-11-12 22:11:26 +0530 | [diff] [blame] | 6330 | continue; |
| 6331 | } |
| 6332 | |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6333 | sgc = rq->sd->groups->sgc; |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6334 | capacity += sgc->capacity; |
Peter Zijlstra | 863bffc | 2013-08-28 11:44:39 +0200 | [diff] [blame] | 6335 | } |
Peter Zijlstra | 74a5ce2 | 2012-05-23 18:00:43 +0200 | [diff] [blame] | 6336 | } else { |
| 6337 | /* |
| 6338 | * !SD_OVERLAP domains can assume that child groups |
| 6339 | * span the current group. |
| 6340 | */ |
| 6341 | |
| 6342 | group = child->groups; |
| 6343 | do { |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6344 | capacity += group->sgc->capacity; |
Peter Zijlstra | 74a5ce2 | 2012-05-23 18:00:43 +0200 | [diff] [blame] | 6345 | group = group->next; |
| 6346 | } while (group != child->groups); |
| 6347 | } |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6348 | |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6349 | sdg->sgc->capacity = capacity; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6350 | } |
| 6351 | |
Srivatsa Vaddagiri | 9d5efe0 | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6352 | /* |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6353 | * Check whether the capacity of the rq has been noticeably reduced by side |
| 6354 | * activity. The imbalance_pct is used for the threshold. |
| 6355 | * Return true is the capacity is reduced |
Srivatsa Vaddagiri | 9d5efe0 | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6356 | */ |
| 6357 | static inline int |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6358 | check_cpu_capacity(struct rq *rq, struct sched_domain *sd) |
Srivatsa Vaddagiri | 9d5efe0 | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6359 | { |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6360 | return ((rq->cpu_capacity * sd->imbalance_pct) < |
| 6361 | (rq->cpu_capacity_orig * 100)); |
Srivatsa Vaddagiri | 9d5efe0 | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6362 | } |
| 6363 | |
Peter Zijlstra | 30ce5da | 2013-08-15 20:29:29 +0200 | [diff] [blame] | 6364 | /* |
| 6365 | * Group imbalance indicates (and tries to solve) the problem where balancing |
| 6366 | * groups is inadequate due to tsk_cpus_allowed() constraints. |
| 6367 | * |
| 6368 | * Imagine a situation of two groups of 4 cpus each and 4 tasks each with a |
| 6369 | * cpumask covering 1 cpu of the first group and 3 cpus of the second group. |
| 6370 | * Something like: |
| 6371 | * |
| 6372 | * { 0 1 2 3 } { 4 5 6 7 } |
| 6373 | * * * * * |
| 6374 | * |
| 6375 | * If we were to balance group-wise we'd place two tasks in the first group and |
| 6376 | * two tasks in the second group. Clearly this is undesired as it will overload |
| 6377 | * cpu 3 and leave one of the cpus in the second group unused. |
| 6378 | * |
| 6379 | * The current solution to this issue is detecting the skew in the first group |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 6380 | * by noticing the lower domain failed to reach balance and had difficulty |
| 6381 | * moving tasks due to affinity constraints. |
Peter Zijlstra | 30ce5da | 2013-08-15 20:29:29 +0200 | [diff] [blame] | 6382 | * |
| 6383 | * When this is so detected; this group becomes a candidate for busiest; see |
Kamalesh Babulal | ed1b773 | 2013-10-13 23:06:15 +0530 | [diff] [blame] | 6384 | * update_sd_pick_busiest(). And calculate_imbalance() and |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 6385 | * find_busiest_group() avoid some of the usual balance conditions to allow it |
Peter Zijlstra | 30ce5da | 2013-08-15 20:29:29 +0200 | [diff] [blame] | 6386 | * to create an effective group imbalance. |
| 6387 | * |
| 6388 | * This is a somewhat tricky proposition since the next run might not find the |
| 6389 | * group imbalance and decide the groups need to be balanced again. A most |
| 6390 | * subtle and fragile situation. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6391 | */ |
Peter Zijlstra | 30ce5da | 2013-08-15 20:29:29 +0200 | [diff] [blame] | 6392 | |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 6393 | static inline int sg_imbalanced(struct sched_group *group) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6394 | { |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6395 | return group->sgc->imbalance; |
Peter Zijlstra | 30ce5da | 2013-08-15 20:29:29 +0200 | [diff] [blame] | 6396 | } |
| 6397 | |
Peter Zijlstra | b37d931 | 2013-08-28 11:50:34 +0200 | [diff] [blame] | 6398 | /* |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6399 | * group_has_capacity returns true if the group has spare capacity that could |
| 6400 | * be used by some tasks. |
| 6401 | * We consider that a group has spare capacity if the * number of task is |
| 6402 | * smaller than the number of CPUs or if the usage is lower than the available |
| 6403 | * capacity for CFS tasks. |
| 6404 | * For the latter, we use a threshold to stabilize the state, to take into |
| 6405 | * account the variance of the tasks' load and to return true if the available |
| 6406 | * capacity in meaningful for the load balancer. |
| 6407 | * As an example, an available capacity of 1% can appear but it doesn't make |
| 6408 | * any benefit for the load balance. |
Peter Zijlstra | b37d931 | 2013-08-28 11:50:34 +0200 | [diff] [blame] | 6409 | */ |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6410 | static inline bool |
| 6411 | group_has_capacity(struct lb_env *env, struct sg_lb_stats *sgs) |
Peter Zijlstra | b37d931 | 2013-08-28 11:50:34 +0200 | [diff] [blame] | 6412 | { |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6413 | if (sgs->sum_nr_running < sgs->group_weight) |
| 6414 | return true; |
Peter Zijlstra | b37d931 | 2013-08-28 11:50:34 +0200 | [diff] [blame] | 6415 | |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6416 | if ((sgs->group_capacity * 100) > |
| 6417 | (sgs->group_usage * env->sd->imbalance_pct)) |
| 6418 | return true; |
Peter Zijlstra | b37d931 | 2013-08-28 11:50:34 +0200 | [diff] [blame] | 6419 | |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6420 | return false; |
Peter Zijlstra | b37d931 | 2013-08-28 11:50:34 +0200 | [diff] [blame] | 6421 | } |
| 6422 | |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6423 | /* |
| 6424 | * group_is_overloaded returns true if the group has more tasks than it can |
| 6425 | * handle. |
| 6426 | * group_is_overloaded is not equals to !group_has_capacity because a group |
| 6427 | * with the exact right number of tasks, has no more spare capacity but is not |
| 6428 | * overloaded so both group_has_capacity and group_is_overloaded return |
| 6429 | * false. |
| 6430 | */ |
| 6431 | static inline bool |
| 6432 | group_is_overloaded(struct lb_env *env, struct sg_lb_stats *sgs) |
Rik van Riel | caeb178 | 2014-07-28 14:16:28 -0400 | [diff] [blame] | 6433 | { |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6434 | if (sgs->sum_nr_running <= sgs->group_weight) |
| 6435 | return false; |
| 6436 | |
| 6437 | if ((sgs->group_capacity * 100) < |
| 6438 | (sgs->group_usage * env->sd->imbalance_pct)) |
| 6439 | return true; |
| 6440 | |
| 6441 | return false; |
| 6442 | } |
| 6443 | |
| 6444 | static enum group_type group_classify(struct lb_env *env, |
| 6445 | struct sched_group *group, |
| 6446 | struct sg_lb_stats *sgs) |
| 6447 | { |
| 6448 | if (sgs->group_no_capacity) |
Rik van Riel | caeb178 | 2014-07-28 14:16:28 -0400 | [diff] [blame] | 6449 | return group_overloaded; |
| 6450 | |
| 6451 | if (sg_imbalanced(group)) |
| 6452 | return group_imbalanced; |
| 6453 | |
| 6454 | return group_other; |
| 6455 | } |
| 6456 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6457 | /** |
| 6458 | * update_sg_lb_stats - Update sched_group's statistics for load balancing. |
| 6459 | * @env: The load balancing environment. |
| 6460 | * @group: sched_group whose statistics are to be updated. |
| 6461 | * @load_idx: Load index of sched_domain of this_cpu for load calc. |
| 6462 | * @local_group: Does group contain this_cpu. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6463 | * @sgs: variable to hold the statistics for this group. |
Masanari Iida | cd3bd4e | 2014-07-28 12:38:06 +0900 | [diff] [blame] | 6464 | * @overload: Indicate more than one runnable task for any CPU. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6465 | */ |
| 6466 | static inline void update_sg_lb_stats(struct lb_env *env, |
| 6467 | struct sched_group *group, int load_idx, |
Tim Chen | 4486edd | 2014-06-23 12:16:49 -0700 | [diff] [blame] | 6468 | int local_group, struct sg_lb_stats *sgs, |
| 6469 | bool *overload) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6470 | { |
Peter Zijlstra | 30ce5da | 2013-08-15 20:29:29 +0200 | [diff] [blame] | 6471 | unsigned long load; |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6472 | int i; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6473 | |
Peter Zijlstra | b72ff13 | 2013-08-28 10:32:32 +0200 | [diff] [blame] | 6474 | memset(sgs, 0, sizeof(*sgs)); |
| 6475 | |
Michael Wang | b9403130 | 2012-07-12 16:10:13 +0800 | [diff] [blame] | 6476 | for_each_cpu_and(i, sched_group_cpus(group), env->cpus) { |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6477 | struct rq *rq = cpu_rq(i); |
| 6478 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6479 | /* Bias balancing toward cpus of our domain */ |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 6480 | if (local_group) |
Peter Zijlstra | 04f733b | 2012-05-11 00:12:02 +0200 | [diff] [blame] | 6481 | load = target_load(i, load_idx); |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 6482 | else |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6483 | load = source_load(i, load_idx); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6484 | |
| 6485 | sgs->group_load += load; |
Vincent Guittot | 8bb5b00 | 2015-03-04 08:48:47 +0100 | [diff] [blame] | 6486 | sgs->group_usage += get_cpu_usage(i); |
Vincent Guittot | 65fdac0 | 2014-08-26 13:06:46 +0200 | [diff] [blame] | 6487 | sgs->sum_nr_running += rq->cfs.h_nr_running; |
Tim Chen | 4486edd | 2014-06-23 12:16:49 -0700 | [diff] [blame] | 6488 | |
| 6489 | if (rq->nr_running > 1) |
| 6490 | *overload = true; |
| 6491 | |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 6492 | #ifdef CONFIG_NUMA_BALANCING |
| 6493 | sgs->nr_numa_running += rq->nr_numa_running; |
| 6494 | sgs->nr_preferred_running += rq->nr_preferred_running; |
| 6495 | #endif |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6496 | sgs->sum_weighted_load += weighted_cpuload(i); |
Suresh Siddha | aae6d3d | 2010-09-17 15:02:32 -0700 | [diff] [blame] | 6497 | if (idle_cpu(i)) |
| 6498 | sgs->idle_cpus++; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6499 | } |
| 6500 | |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6501 | /* Adjust by relative CPU capacity of the group */ |
| 6502 | sgs->group_capacity = group->sgc->capacity; |
Nicolas Pitre | ca8ce3d | 2014-05-26 18:19:39 -0400 | [diff] [blame] | 6503 | sgs->avg_load = (sgs->group_load*SCHED_CAPACITY_SCALE) / sgs->group_capacity; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6504 | |
Suresh Siddha | dd5feea | 2010-02-23 16:13:52 -0800 | [diff] [blame] | 6505 | if (sgs->sum_nr_running) |
Peter Zijlstra | 38d0f77 | 2013-08-15 19:47:56 +0200 | [diff] [blame] | 6506 | sgs->load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6507 | |
Suresh Siddha | aae6d3d | 2010-09-17 15:02:32 -0700 | [diff] [blame] | 6508 | sgs->group_weight = group->group_weight; |
Peter Zijlstra | b37d931 | 2013-08-28 11:50:34 +0200 | [diff] [blame] | 6509 | |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6510 | sgs->group_no_capacity = group_is_overloaded(env, sgs); |
| 6511 | sgs->group_type = group_classify(env, group, sgs); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6512 | } |
| 6513 | |
| 6514 | /** |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6515 | * update_sd_pick_busiest - return 1 on busiest group |
Randy Dunlap | cd96891 | 2012-06-08 13:18:33 -0700 | [diff] [blame] | 6516 | * @env: The load balancing environment. |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6517 | * @sds: sched_domain statistics |
| 6518 | * @sg: sched_group candidate to be checked for being the busiest |
Michael Neuling | b6b1229 | 2010-06-10 12:06:21 +1000 | [diff] [blame] | 6519 | * @sgs: sched_group statistics |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6520 | * |
| 6521 | * Determine if @sg is a busier group than the previously selected |
| 6522 | * busiest group. |
Yacine Belkadi | e69f618 | 2013-07-12 20:45:47 +0200 | [diff] [blame] | 6523 | * |
| 6524 | * Return: %true if @sg is a busier group than the previously selected |
| 6525 | * busiest group. %false otherwise. |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6526 | */ |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6527 | static bool update_sd_pick_busiest(struct lb_env *env, |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6528 | struct sd_lb_stats *sds, |
| 6529 | struct sched_group *sg, |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6530 | struct sg_lb_stats *sgs) |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6531 | { |
Rik van Riel | caeb178 | 2014-07-28 14:16:28 -0400 | [diff] [blame] | 6532 | struct sg_lb_stats *busiest = &sds->busiest_stat; |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6533 | |
Rik van Riel | caeb178 | 2014-07-28 14:16:28 -0400 | [diff] [blame] | 6534 | if (sgs->group_type > busiest->group_type) |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6535 | return true; |
| 6536 | |
Rik van Riel | caeb178 | 2014-07-28 14:16:28 -0400 | [diff] [blame] | 6537 | if (sgs->group_type < busiest->group_type) |
| 6538 | return false; |
| 6539 | |
| 6540 | if (sgs->avg_load <= busiest->avg_load) |
| 6541 | return false; |
| 6542 | |
| 6543 | /* This is the busiest node in its class. */ |
| 6544 | if (!(env->sd->flags & SD_ASYM_PACKING)) |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6545 | return true; |
| 6546 | |
| 6547 | /* |
| 6548 | * ASYM_PACKING needs to move all the work to the lowest |
| 6549 | * numbered CPUs in the group, therefore mark all groups |
| 6550 | * higher than ourself as busy. |
| 6551 | */ |
Rik van Riel | caeb178 | 2014-07-28 14:16:28 -0400 | [diff] [blame] | 6552 | if (sgs->sum_nr_running && env->dst_cpu < group_first_cpu(sg)) { |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6553 | if (!sds->busiest) |
| 6554 | return true; |
| 6555 | |
| 6556 | if (group_first_cpu(sds->busiest) > group_first_cpu(sg)) |
| 6557 | return true; |
| 6558 | } |
| 6559 | |
| 6560 | return false; |
| 6561 | } |
| 6562 | |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 6563 | #ifdef CONFIG_NUMA_BALANCING |
| 6564 | static inline enum fbq_type fbq_classify_group(struct sg_lb_stats *sgs) |
| 6565 | { |
| 6566 | if (sgs->sum_nr_running > sgs->nr_numa_running) |
| 6567 | return regular; |
| 6568 | if (sgs->sum_nr_running > sgs->nr_preferred_running) |
| 6569 | return remote; |
| 6570 | return all; |
| 6571 | } |
| 6572 | |
| 6573 | static inline enum fbq_type fbq_classify_rq(struct rq *rq) |
| 6574 | { |
| 6575 | if (rq->nr_running > rq->nr_numa_running) |
| 6576 | return regular; |
| 6577 | if (rq->nr_running > rq->nr_preferred_running) |
| 6578 | return remote; |
| 6579 | return all; |
| 6580 | } |
| 6581 | #else |
| 6582 | static inline enum fbq_type fbq_classify_group(struct sg_lb_stats *sgs) |
| 6583 | { |
| 6584 | return all; |
| 6585 | } |
| 6586 | |
| 6587 | static inline enum fbq_type fbq_classify_rq(struct rq *rq) |
| 6588 | { |
| 6589 | return regular; |
| 6590 | } |
| 6591 | #endif /* CONFIG_NUMA_BALANCING */ |
| 6592 | |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6593 | /** |
Hui Kang | 461819a | 2011-10-11 23:00:59 -0400 | [diff] [blame] | 6594 | * update_sd_lb_stats - Update sched_domain's statistics for load balancing. |
Randy Dunlap | cd96891 | 2012-06-08 13:18:33 -0700 | [diff] [blame] | 6595 | * @env: The load balancing environment. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6596 | * @sds: variable to hold the statistics for this sched_domain. |
| 6597 | */ |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 6598 | static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sds) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6599 | { |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6600 | struct sched_domain *child = env->sd->child; |
| 6601 | struct sched_group *sg = env->sd->groups; |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6602 | struct sg_lb_stats tmp_sgs; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6603 | int load_idx, prefer_sibling = 0; |
Tim Chen | 4486edd | 2014-06-23 12:16:49 -0700 | [diff] [blame] | 6604 | bool overload = false; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6605 | |
| 6606 | if (child && child->flags & SD_PREFER_SIBLING) |
| 6607 | prefer_sibling = 1; |
| 6608 | |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6609 | load_idx = get_sd_load_idx(env->sd, env->idle); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6610 | |
| 6611 | do { |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6612 | struct sg_lb_stats *sgs = &tmp_sgs; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6613 | int local_group; |
| 6614 | |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6615 | local_group = cpumask_test_cpu(env->dst_cpu, sched_group_cpus(sg)); |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6616 | if (local_group) { |
| 6617 | sds->local = sg; |
| 6618 | sgs = &sds->local_stat; |
Peter Zijlstra | b72ff13 | 2013-08-28 10:32:32 +0200 | [diff] [blame] | 6619 | |
| 6620 | if (env->idle != CPU_NEWLY_IDLE || |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6621 | time_after_eq(jiffies, sg->sgc->next_update)) |
| 6622 | update_group_capacity(env->sd, env->dst_cpu); |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6623 | } |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6624 | |
Tim Chen | 4486edd | 2014-06-23 12:16:49 -0700 | [diff] [blame] | 6625 | update_sg_lb_stats(env, sg, load_idx, local_group, sgs, |
| 6626 | &overload); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6627 | |
Peter Zijlstra | b72ff13 | 2013-08-28 10:32:32 +0200 | [diff] [blame] | 6628 | if (local_group) |
| 6629 | goto next_group; |
| 6630 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6631 | /* |
| 6632 | * In case the child domain prefers tasks go to siblings |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6633 | * first, lower the sg capacity so that we'll try |
Nikhil Rao | 75dd321 | 2010-10-15 13:12:30 -0700 | [diff] [blame] | 6634 | * and move all the excess tasks away. We lower the capacity |
| 6635 | * of a group only if the local group has the capacity to fit |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6636 | * these excess tasks. The extra check prevents the case where |
| 6637 | * you always pull from the heaviest group when it is already |
| 6638 | * under-utilized (possible with a large weight task outweighs |
| 6639 | * the tasks on the system). |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6640 | */ |
Peter Zijlstra | b72ff13 | 2013-08-28 10:32:32 +0200 | [diff] [blame] | 6641 | if (prefer_sibling && sds->local && |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6642 | group_has_capacity(env, &sds->local_stat) && |
| 6643 | (sgs->sum_nr_running > 1)) { |
| 6644 | sgs->group_no_capacity = 1; |
| 6645 | sgs->group_type = group_overloaded; |
Wanpeng Li | cb0b9f2 | 2014-11-05 07:44:50 +0800 | [diff] [blame] | 6646 | } |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6647 | |
Peter Zijlstra | b72ff13 | 2013-08-28 10:32:32 +0200 | [diff] [blame] | 6648 | if (update_sd_pick_busiest(env, sds, sg, sgs)) { |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6649 | sds->busiest = sg; |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6650 | sds->busiest_stat = *sgs; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6651 | } |
| 6652 | |
Peter Zijlstra | b72ff13 | 2013-08-28 10:32:32 +0200 | [diff] [blame] | 6653 | next_group: |
| 6654 | /* Now, start updating sd_lb_stats */ |
| 6655 | sds->total_load += sgs->group_load; |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6656 | sds->total_capacity += sgs->group_capacity; |
Peter Zijlstra | b72ff13 | 2013-08-28 10:32:32 +0200 | [diff] [blame] | 6657 | |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6658 | sg = sg->next; |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6659 | } while (sg != env->sd->groups); |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 6660 | |
| 6661 | if (env->sd->flags & SD_NUMA) |
| 6662 | env->fbq_type = fbq_classify_group(&sds->busiest_stat); |
Tim Chen | 4486edd | 2014-06-23 12:16:49 -0700 | [diff] [blame] | 6663 | |
| 6664 | if (!env->sd->parent) { |
| 6665 | /* update overload indicator if we are at root domain */ |
| 6666 | if (env->dst_rq->rd->overload != overload) |
| 6667 | env->dst_rq->rd->overload = overload; |
| 6668 | } |
| 6669 | |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6670 | } |
| 6671 | |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6672 | /** |
| 6673 | * check_asym_packing - Check to see if the group is packed into the |
| 6674 | * sched doman. |
| 6675 | * |
| 6676 | * This is primarily intended to used at the sibling level. Some |
| 6677 | * cores like POWER7 prefer to use lower numbered SMT threads. In the |
| 6678 | * case of POWER7, it can move to lower SMT modes only when higher |
| 6679 | * threads are idle. When in lower SMT modes, the threads will |
| 6680 | * perform better since they share less core resources. Hence when we |
| 6681 | * have idle threads, we want them to be the higher ones. |
| 6682 | * |
| 6683 | * This packing function is run on idle threads. It checks to see if |
| 6684 | * the busiest CPU in this domain (core in the P7 case) has a higher |
| 6685 | * CPU number than the packing function is being run on. Here we are |
| 6686 | * assuming lower CPU number will be equivalent to lower a SMT thread |
| 6687 | * number. |
| 6688 | * |
Yacine Belkadi | e69f618 | 2013-07-12 20:45:47 +0200 | [diff] [blame] | 6689 | * Return: 1 when packing is required and a task should be moved to |
Michael Neuling | b6b1229 | 2010-06-10 12:06:21 +1000 | [diff] [blame] | 6690 | * this CPU. The amount of the imbalance is returned in *imbalance. |
| 6691 | * |
Randy Dunlap | cd96891 | 2012-06-08 13:18:33 -0700 | [diff] [blame] | 6692 | * @env: The load balancing environment. |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6693 | * @sds: Statistics of the sched_domain which is to be packed |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6694 | */ |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6695 | static int check_asym_packing(struct lb_env *env, struct sd_lb_stats *sds) |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6696 | { |
| 6697 | int busiest_cpu; |
| 6698 | |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6699 | if (!(env->sd->flags & SD_ASYM_PACKING)) |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6700 | return 0; |
| 6701 | |
| 6702 | if (!sds->busiest) |
| 6703 | return 0; |
| 6704 | |
| 6705 | busiest_cpu = group_first_cpu(sds->busiest); |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6706 | if (env->dst_cpu > busiest_cpu) |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6707 | return 0; |
| 6708 | |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6709 | env->imbalance = DIV_ROUND_CLOSEST( |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6710 | sds->busiest_stat.avg_load * sds->busiest_stat.group_capacity, |
Nicolas Pitre | ca8ce3d | 2014-05-26 18:19:39 -0400 | [diff] [blame] | 6711 | SCHED_CAPACITY_SCALE); |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6712 | |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6713 | return 1; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6714 | } |
| 6715 | |
| 6716 | /** |
| 6717 | * fix_small_imbalance - Calculate the minor imbalance that exists |
| 6718 | * amongst the groups of a sched_domain, during |
| 6719 | * load balancing. |
Randy Dunlap | cd96891 | 2012-06-08 13:18:33 -0700 | [diff] [blame] | 6720 | * @env: The load balancing environment. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6721 | * @sds: Statistics of the sched_domain whose imbalance is to be calculated. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6722 | */ |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6723 | static inline |
| 6724 | void fix_small_imbalance(struct lb_env *env, struct sd_lb_stats *sds) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6725 | { |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6726 | unsigned long tmp, capa_now = 0, capa_move = 0; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6727 | unsigned int imbn = 2; |
Suresh Siddha | dd5feea | 2010-02-23 16:13:52 -0800 | [diff] [blame] | 6728 | unsigned long scaled_busy_load_per_task; |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6729 | struct sg_lb_stats *local, *busiest; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6730 | |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6731 | local = &sds->local_stat; |
| 6732 | busiest = &sds->busiest_stat; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6733 | |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6734 | if (!local->sum_nr_running) |
| 6735 | local->load_per_task = cpu_avg_load_per_task(env->dst_cpu); |
| 6736 | else if (busiest->load_per_task > local->load_per_task) |
| 6737 | imbn = 1; |
Suresh Siddha | dd5feea | 2010-02-23 16:13:52 -0800 | [diff] [blame] | 6738 | |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6739 | scaled_busy_load_per_task = |
Nicolas Pitre | ca8ce3d | 2014-05-26 18:19:39 -0400 | [diff] [blame] | 6740 | (busiest->load_per_task * SCHED_CAPACITY_SCALE) / |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6741 | busiest->group_capacity; |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6742 | |
Vladimir Davydov | 3029ede | 2013-09-15 17:49:14 +0400 | [diff] [blame] | 6743 | if (busiest->avg_load + scaled_busy_load_per_task >= |
| 6744 | local->avg_load + (scaled_busy_load_per_task * imbn)) { |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6745 | env->imbalance = busiest->load_per_task; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6746 | return; |
| 6747 | } |
| 6748 | |
| 6749 | /* |
| 6750 | * OK, we don't have enough imbalance to justify moving tasks, |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 6751 | * however we may be able to increase total CPU capacity used by |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6752 | * moving them. |
| 6753 | */ |
| 6754 | |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6755 | capa_now += busiest->group_capacity * |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6756 | min(busiest->load_per_task, busiest->avg_load); |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6757 | capa_now += local->group_capacity * |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6758 | min(local->load_per_task, local->avg_load); |
Nicolas Pitre | ca8ce3d | 2014-05-26 18:19:39 -0400 | [diff] [blame] | 6759 | capa_now /= SCHED_CAPACITY_SCALE; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6760 | |
| 6761 | /* Amount of load we'd subtract */ |
Vincent Guittot | a2cd426 | 2014-03-11 17:26:06 +0100 | [diff] [blame] | 6762 | if (busiest->avg_load > scaled_busy_load_per_task) { |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6763 | capa_move += busiest->group_capacity * |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6764 | min(busiest->load_per_task, |
Vincent Guittot | a2cd426 | 2014-03-11 17:26:06 +0100 | [diff] [blame] | 6765 | busiest->avg_load - scaled_busy_load_per_task); |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6766 | } |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6767 | |
| 6768 | /* Amount of load we'd add */ |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6769 | if (busiest->avg_load * busiest->group_capacity < |
Nicolas Pitre | ca8ce3d | 2014-05-26 18:19:39 -0400 | [diff] [blame] | 6770 | busiest->load_per_task * SCHED_CAPACITY_SCALE) { |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6771 | tmp = (busiest->avg_load * busiest->group_capacity) / |
| 6772 | local->group_capacity; |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6773 | } else { |
Nicolas Pitre | ca8ce3d | 2014-05-26 18:19:39 -0400 | [diff] [blame] | 6774 | tmp = (busiest->load_per_task * SCHED_CAPACITY_SCALE) / |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6775 | local->group_capacity; |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6776 | } |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6777 | capa_move += local->group_capacity * |
Peter Zijlstra | 3ae11c9 | 2013-08-15 20:37:48 +0200 | [diff] [blame] | 6778 | min(local->load_per_task, local->avg_load + tmp); |
Nicolas Pitre | ca8ce3d | 2014-05-26 18:19:39 -0400 | [diff] [blame] | 6779 | capa_move /= SCHED_CAPACITY_SCALE; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6780 | |
| 6781 | /* Move if we gain throughput */ |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6782 | if (capa_move > capa_now) |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6783 | env->imbalance = busiest->load_per_task; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6784 | } |
| 6785 | |
| 6786 | /** |
| 6787 | * calculate_imbalance - Calculate the amount of imbalance present within the |
| 6788 | * groups of a given sched_domain during load balance. |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6789 | * @env: load balance environment |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6790 | * @sds: statistics of the sched_domain whose imbalance is to be calculated. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6791 | */ |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6792 | static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *sds) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6793 | { |
Suresh Siddha | dd5feea | 2010-02-23 16:13:52 -0800 | [diff] [blame] | 6794 | unsigned long max_pull, load_above_capacity = ~0UL; |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6795 | struct sg_lb_stats *local, *busiest; |
Suresh Siddha | dd5feea | 2010-02-23 16:13:52 -0800 | [diff] [blame] | 6796 | |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6797 | local = &sds->local_stat; |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6798 | busiest = &sds->busiest_stat; |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6799 | |
Rik van Riel | caeb178 | 2014-07-28 14:16:28 -0400 | [diff] [blame] | 6800 | if (busiest->group_type == group_imbalanced) { |
Peter Zijlstra | 30ce5da | 2013-08-15 20:29:29 +0200 | [diff] [blame] | 6801 | /* |
| 6802 | * In the group_imb case we cannot rely on group-wide averages |
| 6803 | * to ensure cpu-load equilibrium, look at wider averages. XXX |
| 6804 | */ |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6805 | busiest->load_per_task = |
| 6806 | min(busiest->load_per_task, sds->avg_load); |
Suresh Siddha | dd5feea | 2010-02-23 16:13:52 -0800 | [diff] [blame] | 6807 | } |
| 6808 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6809 | /* |
| 6810 | * In the presence of smp nice balancing, certain scenarios can have |
| 6811 | * max load less than avg load(as we skip the groups at or below |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 6812 | * its cpu_capacity, while calculating max_load..) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6813 | */ |
Vladimir Davydov | b188555 | 2013-09-15 17:49:13 +0400 | [diff] [blame] | 6814 | if (busiest->avg_load <= sds->avg_load || |
| 6815 | local->avg_load >= sds->avg_load) { |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6816 | env->imbalance = 0; |
| 6817 | return fix_small_imbalance(env, sds); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6818 | } |
| 6819 | |
Peter Zijlstra | 9a5d9ba | 2014-07-29 17:15:11 +0200 | [diff] [blame] | 6820 | /* |
| 6821 | * If there aren't any idle cpus, avoid creating some. |
| 6822 | */ |
| 6823 | if (busiest->group_type == group_overloaded && |
| 6824 | local->group_type == group_overloaded) { |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6825 | load_above_capacity = busiest->sum_nr_running * |
| 6826 | SCHED_LOAD_SCALE; |
| 6827 | if (load_above_capacity > busiest->group_capacity) |
| 6828 | load_above_capacity -= busiest->group_capacity; |
| 6829 | else |
| 6830 | load_above_capacity = ~0UL; |
Suresh Siddha | dd5feea | 2010-02-23 16:13:52 -0800 | [diff] [blame] | 6831 | } |
| 6832 | |
| 6833 | /* |
| 6834 | * We're trying to get all the cpus to the average_load, so we don't |
| 6835 | * want to push ourselves above the average load, nor do we wish to |
| 6836 | * reduce the max loaded cpu below the average load. At the same time, |
| 6837 | * we also don't want to reduce the group load below the group capacity |
| 6838 | * (so that we can implement power-savings policies etc). Thus we look |
| 6839 | * for the minimum possible imbalance. |
Suresh Siddha | dd5feea | 2010-02-23 16:13:52 -0800 | [diff] [blame] | 6840 | */ |
Peter Zijlstra | 30ce5da | 2013-08-15 20:29:29 +0200 | [diff] [blame] | 6841 | max_pull = min(busiest->avg_load - sds->avg_load, load_above_capacity); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6842 | |
| 6843 | /* How much load to actually move to equalise the imbalance */ |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6844 | env->imbalance = min( |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 6845 | max_pull * busiest->group_capacity, |
| 6846 | (sds->avg_load - local->avg_load) * local->group_capacity |
Nicolas Pitre | ca8ce3d | 2014-05-26 18:19:39 -0400 | [diff] [blame] | 6847 | ) / SCHED_CAPACITY_SCALE; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6848 | |
| 6849 | /* |
| 6850 | * if *imbalance is less than the average load per runnable task |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 6851 | * there is no guarantee that any tasks will be moved so we'll have |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6852 | * a think about bumping its value to force at least one task to be |
| 6853 | * moved |
| 6854 | */ |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6855 | if (env->imbalance < busiest->load_per_task) |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6856 | return fix_small_imbalance(env, sds); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6857 | } |
Nikhil Rao | fab4762 | 2010-10-15 13:12:29 -0700 | [diff] [blame] | 6858 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6859 | /******* find_busiest_group() helpers end here *********************/ |
| 6860 | |
| 6861 | /** |
| 6862 | * find_busiest_group - Returns the busiest group within the sched_domain |
| 6863 | * if there is an imbalance. If there isn't an imbalance, and |
| 6864 | * the user has opted for power-savings, it returns a group whose |
| 6865 | * CPUs can be put to idle by rebalancing those tasks elsewhere, if |
| 6866 | * such a group exists. |
| 6867 | * |
| 6868 | * Also calculates the amount of weighted load which should be moved |
| 6869 | * to restore balance. |
| 6870 | * |
Randy Dunlap | cd96891 | 2012-06-08 13:18:33 -0700 | [diff] [blame] | 6871 | * @env: The load balancing environment. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6872 | * |
Yacine Belkadi | e69f618 | 2013-07-12 20:45:47 +0200 | [diff] [blame] | 6873 | * Return: - The busiest group if imbalance exists. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6874 | * - If no imbalance and user has opted for power-savings balance, |
| 6875 | * return the least loaded group whose CPUs can be |
| 6876 | * put to idle by rebalancing its tasks onto our group. |
| 6877 | */ |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6878 | static struct sched_group *find_busiest_group(struct lb_env *env) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6879 | { |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6880 | struct sg_lb_stats *local, *busiest; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6881 | struct sd_lb_stats sds; |
| 6882 | |
Peter Zijlstra | 147c5fc2 | 2013-08-19 15:22:57 +0200 | [diff] [blame] | 6883 | init_sd_lb_stats(&sds); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6884 | |
| 6885 | /* |
| 6886 | * Compute the various statistics relavent for load balancing at |
| 6887 | * this level. |
| 6888 | */ |
Joonsoo Kim | 23f0d20 | 2013-08-06 17:36:42 +0900 | [diff] [blame] | 6889 | update_sd_lb_stats(env, &sds); |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6890 | local = &sds.local_stat; |
| 6891 | busiest = &sds.busiest_stat; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6892 | |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6893 | /* ASYM feature bypasses nice load balance check */ |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6894 | if ((env->idle == CPU_IDLE || env->idle == CPU_NEWLY_IDLE) && |
| 6895 | check_asym_packing(env, &sds)) |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 6896 | return sds.busiest; |
| 6897 | |
Peter Zijlstra | cc57aa8 | 2011-02-21 18:55:32 +0100 | [diff] [blame] | 6898 | /* There is no busy sibling group to pull tasks from */ |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6899 | if (!sds.busiest || busiest->sum_nr_running == 0) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6900 | goto out_balanced; |
| 6901 | |
Nicolas Pitre | ca8ce3d | 2014-05-26 18:19:39 -0400 | [diff] [blame] | 6902 | sds.avg_load = (SCHED_CAPACITY_SCALE * sds.total_load) |
| 6903 | / sds.total_capacity; |
Ken Chen | b0432d8 | 2011-04-07 17:23:22 -0700 | [diff] [blame] | 6904 | |
Peter Zijlstra | 866ab43 | 2011-02-21 18:56:47 +0100 | [diff] [blame] | 6905 | /* |
| 6906 | * If the busiest group is imbalanced the below checks don't |
Peter Zijlstra | 30ce5da | 2013-08-15 20:29:29 +0200 | [diff] [blame] | 6907 | * work because they assume all things are equal, which typically |
Peter Zijlstra | 866ab43 | 2011-02-21 18:56:47 +0100 | [diff] [blame] | 6908 | * isn't true due to cpus_allowed constraints and the like. |
| 6909 | */ |
Rik van Riel | caeb178 | 2014-07-28 14:16:28 -0400 | [diff] [blame] | 6910 | if (busiest->group_type == group_imbalanced) |
Peter Zijlstra | 866ab43 | 2011-02-21 18:56:47 +0100 | [diff] [blame] | 6911 | goto force_balance; |
| 6912 | |
Peter Zijlstra | cc57aa8 | 2011-02-21 18:55:32 +0100 | [diff] [blame] | 6913 | /* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */ |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6914 | if (env->idle == CPU_NEWLY_IDLE && group_has_capacity(env, local) && |
| 6915 | busiest->group_no_capacity) |
Nikhil Rao | fab4762 | 2010-10-15 13:12:29 -0700 | [diff] [blame] | 6916 | goto force_balance; |
| 6917 | |
Peter Zijlstra | cc57aa8 | 2011-02-21 18:55:32 +0100 | [diff] [blame] | 6918 | /* |
Zhihui Zhang | 9c58c79 | 2014-09-20 21:24:36 -0400 | [diff] [blame] | 6919 | * If the local group is busier than the selected busiest group |
Peter Zijlstra | cc57aa8 | 2011-02-21 18:55:32 +0100 | [diff] [blame] | 6920 | * don't try and pull any tasks. |
| 6921 | */ |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6922 | if (local->avg_load >= busiest->avg_load) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6923 | goto out_balanced; |
| 6924 | |
Peter Zijlstra | cc57aa8 | 2011-02-21 18:55:32 +0100 | [diff] [blame] | 6925 | /* |
| 6926 | * Don't pull any tasks if this group is already above the domain |
| 6927 | * average load. |
| 6928 | */ |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6929 | if (local->avg_load >= sds.avg_load) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6930 | goto out_balanced; |
| 6931 | |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6932 | if (env->idle == CPU_IDLE) { |
Suresh Siddha | aae6d3d | 2010-09-17 15:02:32 -0700 | [diff] [blame] | 6933 | /* |
Vincent Guittot | 43f4d66 | 2014-10-01 15:38:55 +0200 | [diff] [blame] | 6934 | * This cpu is idle. If the busiest group is not overloaded |
| 6935 | * and there is no imbalance between this and busiest group |
| 6936 | * wrt idle cpus, it is balanced. The imbalance becomes |
| 6937 | * significant if the diff is greater than 1 otherwise we |
| 6938 | * might end up to just move the imbalance on another group |
Suresh Siddha | aae6d3d | 2010-09-17 15:02:32 -0700 | [diff] [blame] | 6939 | */ |
Vincent Guittot | 43f4d66 | 2014-10-01 15:38:55 +0200 | [diff] [blame] | 6940 | if ((busiest->group_type != group_overloaded) && |
| 6941 | (local->idle_cpus <= (busiest->idle_cpus + 1))) |
Suresh Siddha | aae6d3d | 2010-09-17 15:02:32 -0700 | [diff] [blame] | 6942 | goto out_balanced; |
Peter Zijlstra | c186faf | 2011-02-21 18:52:53 +0100 | [diff] [blame] | 6943 | } else { |
| 6944 | /* |
| 6945 | * In the CPU_NEWLY_IDLE, CPU_NOT_IDLE cases, use |
| 6946 | * imbalance_pct to be conservative. |
| 6947 | */ |
Joonsoo Kim | 56cf515 | 2013-08-06 17:36:43 +0900 | [diff] [blame] | 6948 | if (100 * busiest->avg_load <= |
| 6949 | env->sd->imbalance_pct * local->avg_load) |
Peter Zijlstra | c186faf | 2011-02-21 18:52:53 +0100 | [diff] [blame] | 6950 | goto out_balanced; |
Suresh Siddha | aae6d3d | 2010-09-17 15:02:32 -0700 | [diff] [blame] | 6951 | } |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6952 | |
Nikhil Rao | fab4762 | 2010-10-15 13:12:29 -0700 | [diff] [blame] | 6953 | force_balance: |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6954 | /* Looks like there is an imbalance. Compute it */ |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6955 | calculate_imbalance(env, &sds); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6956 | return sds.busiest; |
| 6957 | |
| 6958 | out_balanced: |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6959 | env->imbalance = 0; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6960 | return NULL; |
| 6961 | } |
| 6962 | |
| 6963 | /* |
| 6964 | * find_busiest_queue - find the busiest runqueue among the cpus in group. |
| 6965 | */ |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 6966 | static struct rq *find_busiest_queue(struct lb_env *env, |
Michael Wang | b9403130 | 2012-07-12 16:10:13 +0800 | [diff] [blame] | 6967 | struct sched_group *group) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6968 | { |
| 6969 | struct rq *busiest = NULL, *rq; |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 6970 | unsigned long busiest_load = 0, busiest_capacity = 1; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6971 | int i; |
| 6972 | |
Peter Zijlstra | 6906a40 | 2013-08-19 15:20:21 +0200 | [diff] [blame] | 6973 | for_each_cpu_and(i, sched_group_cpus(group), env->cpus) { |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 6974 | unsigned long capacity, wl; |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 6975 | enum fbq_type rt; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 6976 | |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 6977 | rq = cpu_rq(i); |
| 6978 | rt = fbq_classify_rq(rq); |
| 6979 | |
| 6980 | /* |
| 6981 | * We classify groups/runqueues into three groups: |
| 6982 | * - regular: there are !numa tasks |
| 6983 | * - remote: there are numa tasks that run on the 'wrong' node |
| 6984 | * - all: there is no distinction |
| 6985 | * |
| 6986 | * In order to avoid migrating ideally placed numa tasks, |
| 6987 | * ignore those when there's better options. |
| 6988 | * |
| 6989 | * If we ignore the actual busiest queue to migrate another |
| 6990 | * task, the next balance pass can still reduce the busiest |
| 6991 | * queue by moving tasks around inside the node. |
| 6992 | * |
| 6993 | * If we cannot move enough load due to this classification |
| 6994 | * the next pass will adjust the group classification and |
| 6995 | * allow migration of more tasks. |
| 6996 | * |
| 6997 | * Both cases only affect the total convergence complexity. |
| 6998 | */ |
| 6999 | if (rt > env->fbq_type) |
| 7000 | continue; |
| 7001 | |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 7002 | capacity = capacity_of(i); |
Srivatsa Vaddagiri | 9d5efe0 | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 7003 | |
Thomas Gleixner | 6e40f5b | 2010-02-16 16:48:56 +0100 | [diff] [blame] | 7004 | wl = weighted_cpuload(i); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7005 | |
Thomas Gleixner | 6e40f5b | 2010-02-16 16:48:56 +0100 | [diff] [blame] | 7006 | /* |
| 7007 | * When comparing with imbalance, use weighted_cpuload() |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 7008 | * which is not scaled with the cpu capacity. |
Thomas Gleixner | 6e40f5b | 2010-02-16 16:48:56 +0100 | [diff] [blame] | 7009 | */ |
Vincent Guittot | ea67821 | 2015-02-27 16:54:11 +0100 | [diff] [blame] | 7010 | |
| 7011 | if (rq->nr_running == 1 && wl > env->imbalance && |
| 7012 | !check_cpu_capacity(rq, env->sd)) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7013 | continue; |
| 7014 | |
Thomas Gleixner | 6e40f5b | 2010-02-16 16:48:56 +0100 | [diff] [blame] | 7015 | /* |
| 7016 | * For the load comparisons with the other cpu's, consider |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 7017 | * the weighted_cpuload() scaled with the cpu capacity, so |
| 7018 | * that the load can be moved away from the cpu that is |
| 7019 | * potentially running at a lower capacity. |
Joonsoo Kim | 95a79b8 | 2013-08-06 17:36:41 +0900 | [diff] [blame] | 7020 | * |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 7021 | * Thus we're looking for max(wl_i / capacity_i), crosswise |
Joonsoo Kim | 95a79b8 | 2013-08-06 17:36:41 +0900 | [diff] [blame] | 7022 | * multiplication to rid ourselves of the division works out |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 7023 | * to: wl_i * capacity_j > wl_j * capacity_i; where j is |
| 7024 | * our previous maximum. |
Thomas Gleixner | 6e40f5b | 2010-02-16 16:48:56 +0100 | [diff] [blame] | 7025 | */ |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 7026 | if (wl * busiest_capacity > busiest_load * capacity) { |
Joonsoo Kim | 95a79b8 | 2013-08-06 17:36:41 +0900 | [diff] [blame] | 7027 | busiest_load = wl; |
Nicolas Pitre | ced549f | 2014-05-26 18:19:38 -0400 | [diff] [blame] | 7028 | busiest_capacity = capacity; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7029 | busiest = rq; |
| 7030 | } |
| 7031 | } |
| 7032 | |
| 7033 | return busiest; |
| 7034 | } |
| 7035 | |
| 7036 | /* |
| 7037 | * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but |
| 7038 | * so long as it is large enough. |
| 7039 | */ |
| 7040 | #define MAX_PINNED_INTERVAL 512 |
| 7041 | |
| 7042 | /* Working cpumask for load_balance and load_balance_newidle. */ |
Joonsoo Kim | e6252c3 | 2013-04-23 17:27:41 +0900 | [diff] [blame] | 7043 | DEFINE_PER_CPU(cpumask_var_t, load_balance_mask); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7044 | |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 7045 | static int need_active_balance(struct lb_env *env) |
Peter Zijlstra | 1af3ed3 | 2009-12-23 15:10:31 +0100 | [diff] [blame] | 7046 | { |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 7047 | struct sched_domain *sd = env->sd; |
| 7048 | |
| 7049 | if (env->idle == CPU_NEWLY_IDLE) { |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 7050 | |
| 7051 | /* |
| 7052 | * ASYM_PACKING needs to force migrate tasks from busy but |
| 7053 | * higher numbered CPUs in order to pack all tasks in the |
| 7054 | * lowest numbered CPUs. |
| 7055 | */ |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 7056 | if ((sd->flags & SD_ASYM_PACKING) && env->src_cpu > env->dst_cpu) |
Michael Neuling | 532cb4c | 2010-06-08 14:57:02 +1000 | [diff] [blame] | 7057 | return 1; |
Peter Zijlstra | 1af3ed3 | 2009-12-23 15:10:31 +0100 | [diff] [blame] | 7058 | } |
| 7059 | |
Vincent Guittot | 1aaf90a | 2015-02-27 16:54:14 +0100 | [diff] [blame] | 7060 | /* |
| 7061 | * The dst_cpu is idle and the src_cpu CPU has only 1 CFS task. |
| 7062 | * It's worth migrating the task if the src_cpu's capacity is reduced |
| 7063 | * because of other sched_class or IRQs if more capacity stays |
| 7064 | * available on dst_cpu. |
| 7065 | */ |
| 7066 | if ((env->idle != CPU_NOT_IDLE) && |
| 7067 | (env->src_rq->cfs.h_nr_running == 1)) { |
| 7068 | if ((check_cpu_capacity(env->src_rq, sd)) && |
| 7069 | (capacity_of(env->src_cpu)*sd->imbalance_pct < capacity_of(env->dst_cpu)*100)) |
| 7070 | return 1; |
| 7071 | } |
| 7072 | |
Peter Zijlstra | 1af3ed3 | 2009-12-23 15:10:31 +0100 | [diff] [blame] | 7073 | return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2); |
| 7074 | } |
| 7075 | |
Tejun Heo | 969c792 | 2010-05-06 18:49:21 +0200 | [diff] [blame] | 7076 | static int active_load_balance_cpu_stop(void *data); |
| 7077 | |
Joonsoo Kim | 23f0d20 | 2013-08-06 17:36:42 +0900 | [diff] [blame] | 7078 | static int should_we_balance(struct lb_env *env) |
| 7079 | { |
| 7080 | struct sched_group *sg = env->sd->groups; |
| 7081 | struct cpumask *sg_cpus, *sg_mask; |
| 7082 | int cpu, balance_cpu = -1; |
| 7083 | |
| 7084 | /* |
| 7085 | * In the newly idle case, we will allow all the cpu's |
| 7086 | * to do the newly idle load balance. |
| 7087 | */ |
| 7088 | if (env->idle == CPU_NEWLY_IDLE) |
| 7089 | return 1; |
| 7090 | |
| 7091 | sg_cpus = sched_group_cpus(sg); |
| 7092 | sg_mask = sched_group_mask(sg); |
| 7093 | /* Try to find first idle cpu */ |
| 7094 | for_each_cpu_and(cpu, sg_cpus, env->cpus) { |
| 7095 | if (!cpumask_test_cpu(cpu, sg_mask) || !idle_cpu(cpu)) |
| 7096 | continue; |
| 7097 | |
| 7098 | balance_cpu = cpu; |
| 7099 | break; |
| 7100 | } |
| 7101 | |
| 7102 | if (balance_cpu == -1) |
| 7103 | balance_cpu = group_balance_cpu(sg); |
| 7104 | |
| 7105 | /* |
| 7106 | * First idle cpu or the first cpu(busiest) in this sched group |
| 7107 | * is eligible for doing load balancing at this and above domains. |
| 7108 | */ |
Joonsoo Kim | b0cff9d | 2013-09-10 15:54:49 +0900 | [diff] [blame] | 7109 | return balance_cpu == env->dst_cpu; |
Joonsoo Kim | 23f0d20 | 2013-08-06 17:36:42 +0900 | [diff] [blame] | 7110 | } |
| 7111 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7112 | /* |
| 7113 | * Check this_cpu to ensure it is balanced within domain. Attempt to move |
| 7114 | * tasks if there is an imbalance. |
| 7115 | */ |
| 7116 | static int load_balance(int this_cpu, struct rq *this_rq, |
| 7117 | struct sched_domain *sd, enum cpu_idle_type idle, |
Joonsoo Kim | 23f0d20 | 2013-08-06 17:36:42 +0900 | [diff] [blame] | 7118 | int *continue_balancing) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7119 | { |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 7120 | int ld_moved, cur_ld_moved, active_balance = 0; |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 7121 | struct sched_domain *sd_parent = sd->parent; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7122 | struct sched_group *group; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7123 | struct rq *busiest; |
| 7124 | unsigned long flags; |
Christoph Lameter | 4ba2968 | 2014-08-26 19:12:21 -0500 | [diff] [blame] | 7125 | struct cpumask *cpus = this_cpu_cpumask_var_ptr(load_balance_mask); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7126 | |
Peter Zijlstra | 8e45cb5 | 2012-02-22 12:47:19 +0100 | [diff] [blame] | 7127 | struct lb_env env = { |
| 7128 | .sd = sd, |
Peter Zijlstra | ddcdf6e | 2012-02-22 19:27:40 +0100 | [diff] [blame] | 7129 | .dst_cpu = this_cpu, |
| 7130 | .dst_rq = this_rq, |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 7131 | .dst_grpmask = sched_group_cpus(sd->groups), |
Peter Zijlstra | 8e45cb5 | 2012-02-22 12:47:19 +0100 | [diff] [blame] | 7132 | .idle = idle, |
Peter Zijlstra | eb95308 | 2012-04-17 13:38:40 +0200 | [diff] [blame] | 7133 | .loop_break = sched_nr_migrate_break, |
Michael Wang | b9403130 | 2012-07-12 16:10:13 +0800 | [diff] [blame] | 7134 | .cpus = cpus, |
Peter Zijlstra | 0ec8aa0 | 2013-10-07 11:29:33 +0100 | [diff] [blame] | 7135 | .fbq_type = all, |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 7136 | .tasks = LIST_HEAD_INIT(env.tasks), |
Peter Zijlstra | 8e45cb5 | 2012-02-22 12:47:19 +0100 | [diff] [blame] | 7137 | }; |
| 7138 | |
Joonsoo Kim | cfc0311 | 2013-04-23 17:27:39 +0900 | [diff] [blame] | 7139 | /* |
| 7140 | * For NEWLY_IDLE load_balancing, we don't need to consider |
| 7141 | * other cpus in our group |
| 7142 | */ |
Joonsoo Kim | e02e60c | 2013-04-23 17:27:42 +0900 | [diff] [blame] | 7143 | if (idle == CPU_NEWLY_IDLE) |
Joonsoo Kim | cfc0311 | 2013-04-23 17:27:39 +0900 | [diff] [blame] | 7144 | env.dst_grpmask = NULL; |
Joonsoo Kim | cfc0311 | 2013-04-23 17:27:39 +0900 | [diff] [blame] | 7145 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7146 | cpumask_copy(cpus, cpu_active_mask); |
| 7147 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7148 | schedstat_inc(sd, lb_count[idle]); |
| 7149 | |
| 7150 | redo: |
Joonsoo Kim | 23f0d20 | 2013-08-06 17:36:42 +0900 | [diff] [blame] | 7151 | if (!should_we_balance(&env)) { |
| 7152 | *continue_balancing = 0; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7153 | goto out_balanced; |
Joonsoo Kim | 23f0d20 | 2013-08-06 17:36:42 +0900 | [diff] [blame] | 7154 | } |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7155 | |
Joonsoo Kim | 23f0d20 | 2013-08-06 17:36:42 +0900 | [diff] [blame] | 7156 | group = find_busiest_group(&env); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7157 | if (!group) { |
| 7158 | schedstat_inc(sd, lb_nobusyg[idle]); |
| 7159 | goto out_balanced; |
| 7160 | } |
| 7161 | |
Michael Wang | b9403130 | 2012-07-12 16:10:13 +0800 | [diff] [blame] | 7162 | busiest = find_busiest_queue(&env, group); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7163 | if (!busiest) { |
| 7164 | schedstat_inc(sd, lb_nobusyq[idle]); |
| 7165 | goto out_balanced; |
| 7166 | } |
| 7167 | |
Michael Wang | 78feefc | 2012-08-06 16:41:59 +0800 | [diff] [blame] | 7168 | BUG_ON(busiest == env.dst_rq); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7169 | |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 7170 | schedstat_add(sd, lb_imbalance[idle], env.imbalance); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7171 | |
Vincent Guittot | 1aaf90a | 2015-02-27 16:54:14 +0100 | [diff] [blame] | 7172 | env.src_cpu = busiest->cpu; |
| 7173 | env.src_rq = busiest; |
| 7174 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7175 | ld_moved = 0; |
| 7176 | if (busiest->nr_running > 1) { |
| 7177 | /* |
| 7178 | * Attempt to move tasks. If find_busiest_group has found |
| 7179 | * an imbalance but busiest->nr_running <= 1, the group is |
| 7180 | * still unbalanced. ld_moved simply stays zero, so it is |
| 7181 | * correctly treated as an imbalance. |
| 7182 | */ |
Peter Zijlstra | 8e45cb5 | 2012-02-22 12:47:19 +0100 | [diff] [blame] | 7183 | env.flags |= LBF_ALL_PINNED; |
Peter Zijlstra | c82513e | 2012-04-26 13:12:27 +0200 | [diff] [blame] | 7184 | env.loop_max = min(sysctl_sched_nr_migrate, busiest->nr_running); |
Peter Zijlstra | 8e45cb5 | 2012-02-22 12:47:19 +0100 | [diff] [blame] | 7185 | |
Peter Zijlstra | 5d6523e | 2012-03-10 00:07:36 +0100 | [diff] [blame] | 7186 | more_balance: |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 7187 | raw_spin_lock_irqsave(&busiest->lock, flags); |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 7188 | |
| 7189 | /* |
| 7190 | * cur_ld_moved - load moved in current iteration |
| 7191 | * ld_moved - cumulative load moved across iterations |
| 7192 | */ |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 7193 | cur_ld_moved = detach_tasks(&env); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7194 | |
| 7195 | /* |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 7196 | * We've detached some tasks from busiest_rq. Every |
| 7197 | * task is masked "TASK_ON_RQ_MIGRATING", so we can safely |
| 7198 | * unlock busiest->lock, and we are able to be sure |
| 7199 | * that nobody can manipulate the tasks in parallel. |
| 7200 | * See task_rq_lock() family for the details. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7201 | */ |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 7202 | |
| 7203 | raw_spin_unlock(&busiest->lock); |
| 7204 | |
| 7205 | if (cur_ld_moved) { |
| 7206 | attach_tasks(&env); |
| 7207 | ld_moved += cur_ld_moved; |
| 7208 | } |
| 7209 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7210 | local_irq_restore(flags); |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 7211 | |
Joonsoo Kim | f1cd085 | 2013-04-23 17:27:37 +0900 | [diff] [blame] | 7212 | if (env.flags & LBF_NEED_BREAK) { |
| 7213 | env.flags &= ~LBF_NEED_BREAK; |
| 7214 | goto more_balance; |
| 7215 | } |
| 7216 | |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 7217 | /* |
| 7218 | * Revisit (affine) tasks on src_cpu that couldn't be moved to |
| 7219 | * us and move them to an alternate dst_cpu in our sched_group |
| 7220 | * where they can run. The upper limit on how many times we |
| 7221 | * iterate on same src_cpu is dependent on number of cpus in our |
| 7222 | * sched_group. |
| 7223 | * |
| 7224 | * This changes load balance semantics a bit on who can move |
| 7225 | * load to a given_cpu. In addition to the given_cpu itself |
| 7226 | * (or a ilb_cpu acting on its behalf where given_cpu is |
| 7227 | * nohz-idle), we now have balance_cpu in a position to move |
| 7228 | * load to given_cpu. In rare situations, this may cause |
| 7229 | * conflicts (balance_cpu and given_cpu/ilb_cpu deciding |
| 7230 | * _independently_ and at _same_ time to move some load to |
| 7231 | * given_cpu) causing exceess load to be moved to given_cpu. |
| 7232 | * This however should not happen so much in practice and |
| 7233 | * moreover subsequent load balance cycles should correct the |
| 7234 | * excess load moved. |
| 7235 | */ |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 7236 | if ((env.flags & LBF_DST_PINNED) && env.imbalance > 0) { |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 7237 | |
Vladimir Davydov | 7aff2e3 | 2013-09-15 21:30:13 +0400 | [diff] [blame] | 7238 | /* Prevent to re-select dst_cpu via env's cpus */ |
| 7239 | cpumask_clear_cpu(env.dst_cpu, env.cpus); |
| 7240 | |
Michael Wang | 78feefc | 2012-08-06 16:41:59 +0800 | [diff] [blame] | 7241 | env.dst_rq = cpu_rq(env.new_dst_cpu); |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 7242 | env.dst_cpu = env.new_dst_cpu; |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 7243 | env.flags &= ~LBF_DST_PINNED; |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 7244 | env.loop = 0; |
| 7245 | env.loop_break = sched_nr_migrate_break; |
Joonsoo Kim | e02e60c | 2013-04-23 17:27:42 +0900 | [diff] [blame] | 7246 | |
Srivatsa Vaddagiri | 88b8dac | 2012-06-19 17:43:15 +0530 | [diff] [blame] | 7247 | /* |
| 7248 | * Go back to "more_balance" rather than "redo" since we |
| 7249 | * need to continue with same src_cpu. |
| 7250 | */ |
| 7251 | goto more_balance; |
| 7252 | } |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7253 | |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 7254 | /* |
| 7255 | * We failed to reach balance because of affinity. |
| 7256 | */ |
| 7257 | if (sd_parent) { |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 7258 | int *group_imbalance = &sd_parent->groups->sgc->imbalance; |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 7259 | |
Vincent Guittot | afdeee0 | 2014-08-26 13:06:44 +0200 | [diff] [blame] | 7260 | if ((env.flags & LBF_SOME_PINNED) && env.imbalance > 0) |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 7261 | *group_imbalance = 1; |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 7262 | } |
| 7263 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7264 | /* All tasks on this runqueue were pinned by CPU affinity */ |
Peter Zijlstra | 8e45cb5 | 2012-02-22 12:47:19 +0100 | [diff] [blame] | 7265 | if (unlikely(env.flags & LBF_ALL_PINNED)) { |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7266 | cpumask_clear_cpu(cpu_of(busiest), cpus); |
Prashanth Nageshappa | bbf18b1 | 2012-06-19 17:52:07 +0530 | [diff] [blame] | 7267 | if (!cpumask_empty(cpus)) { |
| 7268 | env.loop = 0; |
| 7269 | env.loop_break = sched_nr_migrate_break; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7270 | goto redo; |
Prashanth Nageshappa | bbf18b1 | 2012-06-19 17:52:07 +0530 | [diff] [blame] | 7271 | } |
Vincent Guittot | afdeee0 | 2014-08-26 13:06:44 +0200 | [diff] [blame] | 7272 | goto out_all_pinned; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7273 | } |
| 7274 | } |
| 7275 | |
| 7276 | if (!ld_moved) { |
| 7277 | schedstat_inc(sd, lb_failed[idle]); |
Venkatesh Pallipadi | 58b26c4 | 2010-09-10 18:19:17 -0700 | [diff] [blame] | 7278 | /* |
| 7279 | * Increment the failure counter only on periodic balance. |
| 7280 | * We do not want newidle balance, which can be very |
| 7281 | * frequent, pollute the failure counter causing |
| 7282 | * excessive cache_hot migrations and active balances. |
| 7283 | */ |
| 7284 | if (idle != CPU_NEWLY_IDLE) |
| 7285 | sd->nr_balance_failed++; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7286 | |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 7287 | if (need_active_balance(&env)) { |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7288 | raw_spin_lock_irqsave(&busiest->lock, flags); |
| 7289 | |
Tejun Heo | 969c792 | 2010-05-06 18:49:21 +0200 | [diff] [blame] | 7290 | /* don't kick the active_load_balance_cpu_stop, |
| 7291 | * if the curr task on busiest cpu can't be |
| 7292 | * moved to this_cpu |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7293 | */ |
| 7294 | if (!cpumask_test_cpu(this_cpu, |
Peter Zijlstra | fa17b50 | 2011-06-16 12:23:22 +0200 | [diff] [blame] | 7295 | tsk_cpus_allowed(busiest->curr))) { |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7296 | raw_spin_unlock_irqrestore(&busiest->lock, |
| 7297 | flags); |
Peter Zijlstra | 8e45cb5 | 2012-02-22 12:47:19 +0100 | [diff] [blame] | 7298 | env.flags |= LBF_ALL_PINNED; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7299 | goto out_one_pinned; |
| 7300 | } |
| 7301 | |
Tejun Heo | 969c792 | 2010-05-06 18:49:21 +0200 | [diff] [blame] | 7302 | /* |
| 7303 | * ->active_balance synchronizes accesses to |
| 7304 | * ->active_balance_work. Once set, it's cleared |
| 7305 | * only after active load balance is finished. |
| 7306 | */ |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7307 | if (!busiest->active_balance) { |
| 7308 | busiest->active_balance = 1; |
| 7309 | busiest->push_cpu = this_cpu; |
| 7310 | active_balance = 1; |
| 7311 | } |
| 7312 | raw_spin_unlock_irqrestore(&busiest->lock, flags); |
Tejun Heo | 969c792 | 2010-05-06 18:49:21 +0200 | [diff] [blame] | 7313 | |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 7314 | if (active_balance) { |
Tejun Heo | 969c792 | 2010-05-06 18:49:21 +0200 | [diff] [blame] | 7315 | stop_one_cpu_nowait(cpu_of(busiest), |
| 7316 | active_load_balance_cpu_stop, busiest, |
| 7317 | &busiest->active_balance_work); |
Peter Zijlstra | bd939f4 | 2012-05-02 14:20:37 +0200 | [diff] [blame] | 7318 | } |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7319 | |
| 7320 | /* |
| 7321 | * We've kicked active balancing, reset the failure |
| 7322 | * counter. |
| 7323 | */ |
| 7324 | sd->nr_balance_failed = sd->cache_nice_tries+1; |
| 7325 | } |
| 7326 | } else |
| 7327 | sd->nr_balance_failed = 0; |
| 7328 | |
| 7329 | if (likely(!active_balance)) { |
| 7330 | /* We were unbalanced, so reset the balancing interval */ |
| 7331 | sd->balance_interval = sd->min_interval; |
| 7332 | } else { |
| 7333 | /* |
| 7334 | * If we've begun active balancing, start to back off. This |
| 7335 | * case may not be covered by the all_pinned logic if there |
| 7336 | * is only 1 task on the busy runqueue (because we don't call |
Kirill Tkhai | 163122b | 2014-08-20 13:48:29 +0400 | [diff] [blame] | 7337 | * detach_tasks). |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7338 | */ |
| 7339 | if (sd->balance_interval < sd->max_interval) |
| 7340 | sd->balance_interval *= 2; |
| 7341 | } |
| 7342 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7343 | goto out; |
| 7344 | |
| 7345 | out_balanced: |
Vincent Guittot | afdeee0 | 2014-08-26 13:06:44 +0200 | [diff] [blame] | 7346 | /* |
| 7347 | * We reach balance although we may have faced some affinity |
| 7348 | * constraints. Clear the imbalance flag if it was set. |
| 7349 | */ |
| 7350 | if (sd_parent) { |
| 7351 | int *group_imbalance = &sd_parent->groups->sgc->imbalance; |
| 7352 | |
| 7353 | if (*group_imbalance) |
| 7354 | *group_imbalance = 0; |
| 7355 | } |
| 7356 | |
| 7357 | out_all_pinned: |
| 7358 | /* |
| 7359 | * We reach balance because all tasks are pinned at this level so |
| 7360 | * we can't migrate them. Let the imbalance flag set so parent level |
| 7361 | * can try to migrate them. |
| 7362 | */ |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7363 | schedstat_inc(sd, lb_balanced[idle]); |
| 7364 | |
| 7365 | sd->nr_balance_failed = 0; |
| 7366 | |
| 7367 | out_one_pinned: |
| 7368 | /* tune up the balancing interval */ |
Peter Zijlstra | 8e45cb5 | 2012-02-22 12:47:19 +0100 | [diff] [blame] | 7369 | if (((env.flags & LBF_ALL_PINNED) && |
Peter Zijlstra | 5b54b56 | 2011-09-22 15:23:13 +0200 | [diff] [blame] | 7370 | sd->balance_interval < MAX_PINNED_INTERVAL) || |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7371 | (sd->balance_interval < sd->max_interval)) |
| 7372 | sd->balance_interval *= 2; |
| 7373 | |
Venkatesh Pallipadi | 46e49b3 | 2011-02-14 14:38:50 -0800 | [diff] [blame] | 7374 | ld_moved = 0; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7375 | out: |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7376 | return ld_moved; |
| 7377 | } |
| 7378 | |
Jason Low | 52a08ef | 2014-05-08 17:49:22 -0700 | [diff] [blame] | 7379 | static inline unsigned long |
| 7380 | get_sd_balance_interval(struct sched_domain *sd, int cpu_busy) |
| 7381 | { |
| 7382 | unsigned long interval = sd->balance_interval; |
| 7383 | |
| 7384 | if (cpu_busy) |
| 7385 | interval *= sd->busy_factor; |
| 7386 | |
| 7387 | /* scale ms to jiffies */ |
| 7388 | interval = msecs_to_jiffies(interval); |
| 7389 | interval = clamp(interval, 1UL, max_load_balance_interval); |
| 7390 | |
| 7391 | return interval; |
| 7392 | } |
| 7393 | |
| 7394 | static inline void |
| 7395 | update_next_balance(struct sched_domain *sd, int cpu_busy, unsigned long *next_balance) |
| 7396 | { |
| 7397 | unsigned long interval, next; |
| 7398 | |
| 7399 | interval = get_sd_balance_interval(sd, cpu_busy); |
| 7400 | next = sd->last_balance + interval; |
| 7401 | |
| 7402 | if (time_after(*next_balance, next)) |
| 7403 | *next_balance = next; |
| 7404 | } |
| 7405 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7406 | /* |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7407 | * idle_balance is called by schedule() if this_cpu is about to become |
| 7408 | * idle. Attempts to pull tasks from other CPUs. |
| 7409 | */ |
Peter Zijlstra | 6e83125 | 2014-02-11 16:11:48 +0100 | [diff] [blame] | 7410 | static int idle_balance(struct rq *this_rq) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7411 | { |
Jason Low | 52a08ef | 2014-05-08 17:49:22 -0700 | [diff] [blame] | 7412 | unsigned long next_balance = jiffies + HZ; |
| 7413 | int this_cpu = this_rq->cpu; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7414 | struct sched_domain *sd; |
| 7415 | int pulled_task = 0; |
Jason Low | 9bd721c | 2013-09-13 11:26:52 -0700 | [diff] [blame] | 7416 | u64 curr_cost = 0; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7417 | |
Peter Zijlstra | 6e83125 | 2014-02-11 16:11:48 +0100 | [diff] [blame] | 7418 | idle_enter_fair(this_rq); |
Jason Low | 0e5b533 | 2014-04-28 15:45:54 -0700 | [diff] [blame] | 7419 | |
Peter Zijlstra | 6e83125 | 2014-02-11 16:11:48 +0100 | [diff] [blame] | 7420 | /* |
| 7421 | * We must set idle_stamp _before_ calling idle_balance(), such that we |
| 7422 | * measure the duration of idle_balance() as idle time. |
| 7423 | */ |
| 7424 | this_rq->idle_stamp = rq_clock(this_rq); |
| 7425 | |
Tim Chen | 4486edd | 2014-06-23 12:16:49 -0700 | [diff] [blame] | 7426 | if (this_rq->avg_idle < sysctl_sched_migration_cost || |
| 7427 | !this_rq->rd->overload) { |
Jason Low | 52a08ef | 2014-05-08 17:49:22 -0700 | [diff] [blame] | 7428 | rcu_read_lock(); |
| 7429 | sd = rcu_dereference_check_sched_domain(this_rq->sd); |
| 7430 | if (sd) |
| 7431 | update_next_balance(sd, 0, &next_balance); |
| 7432 | rcu_read_unlock(); |
| 7433 | |
Peter Zijlstra | 6e83125 | 2014-02-11 16:11:48 +0100 | [diff] [blame] | 7434 | goto out; |
Jason Low | 52a08ef | 2014-05-08 17:49:22 -0700 | [diff] [blame] | 7435 | } |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7436 | |
Peter Zijlstra | f492e12 | 2009-12-23 15:29:42 +0100 | [diff] [blame] | 7437 | raw_spin_unlock(&this_rq->lock); |
| 7438 | |
Paul Turner | 48a1675 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 7439 | update_blocked_averages(this_cpu); |
Peter Zijlstra | dce840a | 2011-04-07 14:09:50 +0200 | [diff] [blame] | 7440 | rcu_read_lock(); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7441 | for_each_domain(this_cpu, sd) { |
Joonsoo Kim | 23f0d20 | 2013-08-06 17:36:42 +0900 | [diff] [blame] | 7442 | int continue_balancing = 1; |
Jason Low | 9bd721c | 2013-09-13 11:26:52 -0700 | [diff] [blame] | 7443 | u64 t0, domain_cost; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7444 | |
| 7445 | if (!(sd->flags & SD_LOAD_BALANCE)) |
| 7446 | continue; |
| 7447 | |
Jason Low | 52a08ef | 2014-05-08 17:49:22 -0700 | [diff] [blame] | 7448 | if (this_rq->avg_idle < curr_cost + sd->max_newidle_lb_cost) { |
| 7449 | update_next_balance(sd, 0, &next_balance); |
Jason Low | 9bd721c | 2013-09-13 11:26:52 -0700 | [diff] [blame] | 7450 | break; |
Jason Low | 52a08ef | 2014-05-08 17:49:22 -0700 | [diff] [blame] | 7451 | } |
Jason Low | 9bd721c | 2013-09-13 11:26:52 -0700 | [diff] [blame] | 7452 | |
Peter Zijlstra | f492e12 | 2009-12-23 15:29:42 +0100 | [diff] [blame] | 7453 | if (sd->flags & SD_BALANCE_NEWIDLE) { |
Jason Low | 9bd721c | 2013-09-13 11:26:52 -0700 | [diff] [blame] | 7454 | t0 = sched_clock_cpu(this_cpu); |
| 7455 | |
Peter Zijlstra | f492e12 | 2009-12-23 15:29:42 +0100 | [diff] [blame] | 7456 | pulled_task = load_balance(this_cpu, this_rq, |
Joonsoo Kim | 23f0d20 | 2013-08-06 17:36:42 +0900 | [diff] [blame] | 7457 | sd, CPU_NEWLY_IDLE, |
| 7458 | &continue_balancing); |
Jason Low | 9bd721c | 2013-09-13 11:26:52 -0700 | [diff] [blame] | 7459 | |
| 7460 | domain_cost = sched_clock_cpu(this_cpu) - t0; |
| 7461 | if (domain_cost > sd->max_newidle_lb_cost) |
| 7462 | sd->max_newidle_lb_cost = domain_cost; |
| 7463 | |
| 7464 | curr_cost += domain_cost; |
Peter Zijlstra | f492e12 | 2009-12-23 15:29:42 +0100 | [diff] [blame] | 7465 | } |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7466 | |
Jason Low | 52a08ef | 2014-05-08 17:49:22 -0700 | [diff] [blame] | 7467 | update_next_balance(sd, 0, &next_balance); |
Jason Low | 39a4d9c | 2014-04-23 18:30:35 -0700 | [diff] [blame] | 7468 | |
| 7469 | /* |
| 7470 | * Stop searching for tasks to pull if there are |
| 7471 | * now runnable tasks on this rq. |
| 7472 | */ |
| 7473 | if (pulled_task || this_rq->nr_running > 0) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7474 | break; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7475 | } |
Peter Zijlstra | dce840a | 2011-04-07 14:09:50 +0200 | [diff] [blame] | 7476 | rcu_read_unlock(); |
Peter Zijlstra | f492e12 | 2009-12-23 15:29:42 +0100 | [diff] [blame] | 7477 | |
| 7478 | raw_spin_lock(&this_rq->lock); |
| 7479 | |
Jason Low | 0e5b533 | 2014-04-28 15:45:54 -0700 | [diff] [blame] | 7480 | if (curr_cost > this_rq->max_idle_balance_cost) |
| 7481 | this_rq->max_idle_balance_cost = curr_cost; |
| 7482 | |
Daniel Lezcano | e5fc661 | 2014-01-17 10:04:02 +0100 | [diff] [blame] | 7483 | /* |
Jason Low | 0e5b533 | 2014-04-28 15:45:54 -0700 | [diff] [blame] | 7484 | * While browsing the domains, we released the rq lock, a task could |
| 7485 | * have been enqueued in the meantime. Since we're not going idle, |
| 7486 | * pretend we pulled a task. |
Daniel Lezcano | e5fc661 | 2014-01-17 10:04:02 +0100 | [diff] [blame] | 7487 | */ |
Jason Low | 0e5b533 | 2014-04-28 15:45:54 -0700 | [diff] [blame] | 7488 | if (this_rq->cfs.h_nr_running && !pulled_task) |
Peter Zijlstra | 6e83125 | 2014-02-11 16:11:48 +0100 | [diff] [blame] | 7489 | pulled_task = 1; |
Daniel Lezcano | e5fc661 | 2014-01-17 10:04:02 +0100 | [diff] [blame] | 7490 | |
Peter Zijlstra | 6e83125 | 2014-02-11 16:11:48 +0100 | [diff] [blame] | 7491 | out: |
Jason Low | 52a08ef | 2014-05-08 17:49:22 -0700 | [diff] [blame] | 7492 | /* Move the next balance forward */ |
| 7493 | if (time_after(this_rq->next_balance, next_balance)) |
| 7494 | this_rq->next_balance = next_balance; |
| 7495 | |
Kirill Tkhai | e4aa358 | 2014-03-06 13:31:55 +0400 | [diff] [blame] | 7496 | /* Is there a task of a high priority class? */ |
Kirill Tkhai | 4638364 | 2014-03-15 02:15:07 +0400 | [diff] [blame] | 7497 | if (this_rq->nr_running != this_rq->cfs.h_nr_running) |
Kirill Tkhai | e4aa358 | 2014-03-06 13:31:55 +0400 | [diff] [blame] | 7498 | pulled_task = -1; |
| 7499 | |
| 7500 | if (pulled_task) { |
| 7501 | idle_exit_fair(this_rq); |
Peter Zijlstra | 6e83125 | 2014-02-11 16:11:48 +0100 | [diff] [blame] | 7502 | this_rq->idle_stamp = 0; |
Kirill Tkhai | e4aa358 | 2014-03-06 13:31:55 +0400 | [diff] [blame] | 7503 | } |
Peter Zijlstra | 6e83125 | 2014-02-11 16:11:48 +0100 | [diff] [blame] | 7504 | |
Daniel Lezcano | 3c4017c | 2014-01-17 10:04:03 +0100 | [diff] [blame] | 7505 | return pulled_task; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7506 | } |
| 7507 | |
| 7508 | /* |
Tejun Heo | 969c792 | 2010-05-06 18:49:21 +0200 | [diff] [blame] | 7509 | * active_load_balance_cpu_stop is run by cpu stopper. It pushes |
| 7510 | * running tasks off the busiest CPU onto idle CPUs. It requires at |
| 7511 | * least 1 task to be running on each physical CPU where possible, and |
| 7512 | * avoids physical / logical imbalances. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7513 | */ |
Tejun Heo | 969c792 | 2010-05-06 18:49:21 +0200 | [diff] [blame] | 7514 | static int active_load_balance_cpu_stop(void *data) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7515 | { |
Tejun Heo | 969c792 | 2010-05-06 18:49:21 +0200 | [diff] [blame] | 7516 | struct rq *busiest_rq = data; |
| 7517 | int busiest_cpu = cpu_of(busiest_rq); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7518 | int target_cpu = busiest_rq->push_cpu; |
Tejun Heo | 969c792 | 2010-05-06 18:49:21 +0200 | [diff] [blame] | 7519 | struct rq *target_rq = cpu_rq(target_cpu); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7520 | struct sched_domain *sd; |
Kirill Tkhai | e5673f2 | 2014-08-20 13:48:01 +0400 | [diff] [blame] | 7521 | struct task_struct *p = NULL; |
Tejun Heo | 969c792 | 2010-05-06 18:49:21 +0200 | [diff] [blame] | 7522 | |
| 7523 | raw_spin_lock_irq(&busiest_rq->lock); |
| 7524 | |
| 7525 | /* make sure the requested cpu hasn't gone down in the meantime */ |
| 7526 | if (unlikely(busiest_cpu != smp_processor_id() || |
| 7527 | !busiest_rq->active_balance)) |
| 7528 | goto out_unlock; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7529 | |
| 7530 | /* Is there any task to move? */ |
| 7531 | if (busiest_rq->nr_running <= 1) |
Tejun Heo | 969c792 | 2010-05-06 18:49:21 +0200 | [diff] [blame] | 7532 | goto out_unlock; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7533 | |
| 7534 | /* |
| 7535 | * This condition is "impossible", if it occurs |
| 7536 | * we need to fix it. Originally reported by |
| 7537 | * Bjorn Helgaas on a 128-cpu setup. |
| 7538 | */ |
| 7539 | BUG_ON(busiest_rq == target_rq); |
| 7540 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7541 | /* Search for an sd spanning us and the target CPU. */ |
Peter Zijlstra | dce840a | 2011-04-07 14:09:50 +0200 | [diff] [blame] | 7542 | rcu_read_lock(); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7543 | for_each_domain(target_cpu, sd) { |
| 7544 | if ((sd->flags & SD_LOAD_BALANCE) && |
| 7545 | cpumask_test_cpu(busiest_cpu, sched_domain_span(sd))) |
| 7546 | break; |
| 7547 | } |
| 7548 | |
| 7549 | if (likely(sd)) { |
Peter Zijlstra | 8e45cb5 | 2012-02-22 12:47:19 +0100 | [diff] [blame] | 7550 | struct lb_env env = { |
| 7551 | .sd = sd, |
Peter Zijlstra | ddcdf6e | 2012-02-22 19:27:40 +0100 | [diff] [blame] | 7552 | .dst_cpu = target_cpu, |
| 7553 | .dst_rq = target_rq, |
| 7554 | .src_cpu = busiest_rq->cpu, |
| 7555 | .src_rq = busiest_rq, |
Peter Zijlstra | 8e45cb5 | 2012-02-22 12:47:19 +0100 | [diff] [blame] | 7556 | .idle = CPU_IDLE, |
| 7557 | }; |
| 7558 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7559 | schedstat_inc(sd, alb_count); |
| 7560 | |
Kirill Tkhai | e5673f2 | 2014-08-20 13:48:01 +0400 | [diff] [blame] | 7561 | p = detach_one_task(&env); |
| 7562 | if (p) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7563 | schedstat_inc(sd, alb_pushed); |
| 7564 | else |
| 7565 | schedstat_inc(sd, alb_failed); |
| 7566 | } |
Peter Zijlstra | dce840a | 2011-04-07 14:09:50 +0200 | [diff] [blame] | 7567 | rcu_read_unlock(); |
Tejun Heo | 969c792 | 2010-05-06 18:49:21 +0200 | [diff] [blame] | 7568 | out_unlock: |
| 7569 | busiest_rq->active_balance = 0; |
Kirill Tkhai | e5673f2 | 2014-08-20 13:48:01 +0400 | [diff] [blame] | 7570 | raw_spin_unlock(&busiest_rq->lock); |
| 7571 | |
| 7572 | if (p) |
| 7573 | attach_one_task(target_rq, p); |
| 7574 | |
| 7575 | local_irq_enable(); |
| 7576 | |
Tejun Heo | 969c792 | 2010-05-06 18:49:21 +0200 | [diff] [blame] | 7577 | return 0; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7578 | } |
| 7579 | |
Mike Galbraith | d987fc7 | 2011-12-05 10:01:47 +0100 | [diff] [blame] | 7580 | static inline int on_null_domain(struct rq *rq) |
| 7581 | { |
| 7582 | return unlikely(!rcu_dereference_sched(rq->sd)); |
| 7583 | } |
| 7584 | |
Frederic Weisbecker | 3451d02 | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 7585 | #ifdef CONFIG_NO_HZ_COMMON |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7586 | /* |
| 7587 | * idle load balancing details |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7588 | * - When one of the busy CPUs notice that there may be an idle rebalancing |
| 7589 | * needed, they will kick the idle load balancer, which then does idle |
| 7590 | * load balancing for all the idle CPUs. |
| 7591 | */ |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7592 | static struct { |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7593 | cpumask_var_t idle_cpus_mask; |
Suresh Siddha | 0b005cf | 2011-12-01 17:07:34 -0800 | [diff] [blame] | 7594 | atomic_t nr_cpus; |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7595 | unsigned long next_balance; /* in jiffy units */ |
| 7596 | } nohz ____cacheline_aligned; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7597 | |
Daniel Lezcano | 3dd0337 | 2014-01-06 12:34:41 +0100 | [diff] [blame] | 7598 | static inline int find_new_ilb(void) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7599 | { |
Suresh Siddha | 0b005cf | 2011-12-01 17:07:34 -0800 | [diff] [blame] | 7600 | int ilb = cpumask_first(nohz.idle_cpus_mask); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7601 | |
Suresh Siddha | 786d6dc | 2011-12-01 17:07:35 -0800 | [diff] [blame] | 7602 | if (ilb < nr_cpu_ids && idle_cpu(ilb)) |
| 7603 | return ilb; |
| 7604 | |
| 7605 | return nr_cpu_ids; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7606 | } |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7607 | |
| 7608 | /* |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7609 | * Kick a CPU to do the nohz balancing, if it is time for it. We pick the |
| 7610 | * nohz_load_balancer CPU (if there is one) otherwise fallback to any idle |
| 7611 | * CPU (if there is one). |
| 7612 | */ |
Daniel Lezcano | 0aeeeeb | 2014-01-06 12:34:42 +0100 | [diff] [blame] | 7613 | static void nohz_balancer_kick(void) |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7614 | { |
| 7615 | int ilb_cpu; |
| 7616 | |
| 7617 | nohz.next_balance++; |
| 7618 | |
Daniel Lezcano | 3dd0337 | 2014-01-06 12:34:41 +0100 | [diff] [blame] | 7619 | ilb_cpu = find_new_ilb(); |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7620 | |
Suresh Siddha | 0b005cf | 2011-12-01 17:07:34 -0800 | [diff] [blame] | 7621 | if (ilb_cpu >= nr_cpu_ids) |
| 7622 | return; |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7623 | |
Suresh Siddha | cd490c5 | 2011-12-06 11:26:34 -0800 | [diff] [blame] | 7624 | if (test_and_set_bit(NOHZ_BALANCE_KICK, nohz_flags(ilb_cpu))) |
Suresh Siddha | 1c792db | 2011-12-01 17:07:32 -0800 | [diff] [blame] | 7625 | return; |
| 7626 | /* |
| 7627 | * Use smp_send_reschedule() instead of resched_cpu(). |
| 7628 | * This way we generate a sched IPI on the target cpu which |
| 7629 | * is idle. And the softirq performing nohz idle load balance |
| 7630 | * will be run before returning from the IPI. |
| 7631 | */ |
| 7632 | smp_send_reschedule(ilb_cpu); |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7633 | return; |
| 7634 | } |
| 7635 | |
Alex Shi | c1cc017 | 2012-09-10 15:10:58 +0800 | [diff] [blame] | 7636 | static inline void nohz_balance_exit_idle(int cpu) |
Suresh Siddha | 7132596 | 2012-01-19 18:28:57 -0800 | [diff] [blame] | 7637 | { |
| 7638 | if (unlikely(test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))) { |
Mike Galbraith | d987fc7 | 2011-12-05 10:01:47 +0100 | [diff] [blame] | 7639 | /* |
| 7640 | * Completely isolated CPUs don't ever set, so we must test. |
| 7641 | */ |
| 7642 | if (likely(cpumask_test_cpu(cpu, nohz.idle_cpus_mask))) { |
| 7643 | cpumask_clear_cpu(cpu, nohz.idle_cpus_mask); |
| 7644 | atomic_dec(&nohz.nr_cpus); |
| 7645 | } |
Suresh Siddha | 7132596 | 2012-01-19 18:28:57 -0800 | [diff] [blame] | 7646 | clear_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)); |
| 7647 | } |
| 7648 | } |
| 7649 | |
Suresh Siddha | 69e1e81 | 2011-12-01 17:07:33 -0800 | [diff] [blame] | 7650 | static inline void set_cpu_sd_state_busy(void) |
| 7651 | { |
| 7652 | struct sched_domain *sd; |
Preeti U Murthy | 37dc6b5 | 2013-10-30 08:42:52 +0530 | [diff] [blame] | 7653 | int cpu = smp_processor_id(); |
Suresh Siddha | 69e1e81 | 2011-12-01 17:07:33 -0800 | [diff] [blame] | 7654 | |
Suresh Siddha | 69e1e81 | 2011-12-01 17:07:33 -0800 | [diff] [blame] | 7655 | rcu_read_lock(); |
Preeti U Murthy | 37dc6b5 | 2013-10-30 08:42:52 +0530 | [diff] [blame] | 7656 | sd = rcu_dereference(per_cpu(sd_busy, cpu)); |
Vincent Guittot | 25f55d9 | 2013-04-23 16:59:02 +0200 | [diff] [blame] | 7657 | |
| 7658 | if (!sd || !sd->nohz_idle) |
| 7659 | goto unlock; |
| 7660 | sd->nohz_idle = 0; |
| 7661 | |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 7662 | atomic_inc(&sd->groups->sgc->nr_busy_cpus); |
Vincent Guittot | 25f55d9 | 2013-04-23 16:59:02 +0200 | [diff] [blame] | 7663 | unlock: |
Suresh Siddha | 69e1e81 | 2011-12-01 17:07:33 -0800 | [diff] [blame] | 7664 | rcu_read_unlock(); |
| 7665 | } |
| 7666 | |
| 7667 | void set_cpu_sd_state_idle(void) |
| 7668 | { |
| 7669 | struct sched_domain *sd; |
Preeti U Murthy | 37dc6b5 | 2013-10-30 08:42:52 +0530 | [diff] [blame] | 7670 | int cpu = smp_processor_id(); |
Suresh Siddha | 69e1e81 | 2011-12-01 17:07:33 -0800 | [diff] [blame] | 7671 | |
Suresh Siddha | 69e1e81 | 2011-12-01 17:07:33 -0800 | [diff] [blame] | 7672 | rcu_read_lock(); |
Preeti U Murthy | 37dc6b5 | 2013-10-30 08:42:52 +0530 | [diff] [blame] | 7673 | sd = rcu_dereference(per_cpu(sd_busy, cpu)); |
Vincent Guittot | 25f55d9 | 2013-04-23 16:59:02 +0200 | [diff] [blame] | 7674 | |
| 7675 | if (!sd || sd->nohz_idle) |
| 7676 | goto unlock; |
| 7677 | sd->nohz_idle = 1; |
| 7678 | |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 7679 | atomic_dec(&sd->groups->sgc->nr_busy_cpus); |
Vincent Guittot | 25f55d9 | 2013-04-23 16:59:02 +0200 | [diff] [blame] | 7680 | unlock: |
Suresh Siddha | 69e1e81 | 2011-12-01 17:07:33 -0800 | [diff] [blame] | 7681 | rcu_read_unlock(); |
| 7682 | } |
| 7683 | |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7684 | /* |
Alex Shi | c1cc017 | 2012-09-10 15:10:58 +0800 | [diff] [blame] | 7685 | * This routine will record that the cpu is going idle with tick stopped. |
Suresh Siddha | 0b005cf | 2011-12-01 17:07:34 -0800 | [diff] [blame] | 7686 | * This info will be used in performing idle load balancing in the future. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7687 | */ |
Alex Shi | c1cc017 | 2012-09-10 15:10:58 +0800 | [diff] [blame] | 7688 | void nohz_balance_enter_idle(int cpu) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7689 | { |
Suresh Siddha | 7132596 | 2012-01-19 18:28:57 -0800 | [diff] [blame] | 7690 | /* |
| 7691 | * If this cpu is going down, then nothing needs to be done. |
| 7692 | */ |
| 7693 | if (!cpu_active(cpu)) |
| 7694 | return; |
| 7695 | |
Alex Shi | c1cc017 | 2012-09-10 15:10:58 +0800 | [diff] [blame] | 7696 | if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu))) |
| 7697 | return; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7698 | |
Mike Galbraith | d987fc7 | 2011-12-05 10:01:47 +0100 | [diff] [blame] | 7699 | /* |
| 7700 | * If we're a completely isolated CPU, we don't play. |
| 7701 | */ |
| 7702 | if (on_null_domain(cpu_rq(cpu))) |
| 7703 | return; |
| 7704 | |
Alex Shi | c1cc017 | 2012-09-10 15:10:58 +0800 | [diff] [blame] | 7705 | cpumask_set_cpu(cpu, nohz.idle_cpus_mask); |
| 7706 | atomic_inc(&nohz.nr_cpus); |
| 7707 | set_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7708 | } |
Suresh Siddha | 7132596 | 2012-01-19 18:28:57 -0800 | [diff] [blame] | 7709 | |
Paul Gortmaker | 0db0628 | 2013-06-19 14:53:51 -0400 | [diff] [blame] | 7710 | static int sched_ilb_notifier(struct notifier_block *nfb, |
Suresh Siddha | 7132596 | 2012-01-19 18:28:57 -0800 | [diff] [blame] | 7711 | unsigned long action, void *hcpu) |
| 7712 | { |
| 7713 | switch (action & ~CPU_TASKS_FROZEN) { |
| 7714 | case CPU_DYING: |
Alex Shi | c1cc017 | 2012-09-10 15:10:58 +0800 | [diff] [blame] | 7715 | nohz_balance_exit_idle(smp_processor_id()); |
Suresh Siddha | 7132596 | 2012-01-19 18:28:57 -0800 | [diff] [blame] | 7716 | return NOTIFY_OK; |
| 7717 | default: |
| 7718 | return NOTIFY_DONE; |
| 7719 | } |
| 7720 | } |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7721 | #endif |
| 7722 | |
| 7723 | static DEFINE_SPINLOCK(balancing); |
| 7724 | |
Peter Zijlstra | 49c022e | 2011-04-05 10:14:25 +0200 | [diff] [blame] | 7725 | /* |
| 7726 | * Scale the max load_balance interval with the number of CPUs in the system. |
| 7727 | * This trades load-balance latency on larger machines for less cross talk. |
| 7728 | */ |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 7729 | void update_max_interval(void) |
Peter Zijlstra | 49c022e | 2011-04-05 10:14:25 +0200 | [diff] [blame] | 7730 | { |
| 7731 | max_load_balance_interval = HZ*num_online_cpus()/10; |
| 7732 | } |
| 7733 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7734 | /* |
| 7735 | * It checks each scheduling domain to see if it is due to be balanced, |
| 7736 | * and initiates a balancing operation if so. |
| 7737 | * |
Libin | b9b0853 | 2013-04-01 19:14:01 +0800 | [diff] [blame] | 7738 | * Balancing parameters are set up in init_sched_domains. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7739 | */ |
Daniel Lezcano | f7ed0a8 | 2014-01-06 12:34:43 +0100 | [diff] [blame] | 7740 | static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7741 | { |
Joonsoo Kim | 23f0d20 | 2013-08-06 17:36:42 +0900 | [diff] [blame] | 7742 | int continue_balancing = 1; |
Daniel Lezcano | f7ed0a8 | 2014-01-06 12:34:43 +0100 | [diff] [blame] | 7743 | int cpu = rq->cpu; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7744 | unsigned long interval; |
Peter Zijlstra | 04f733b | 2012-05-11 00:12:02 +0200 | [diff] [blame] | 7745 | struct sched_domain *sd; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7746 | /* Earliest time when we have to do rebalance again */ |
| 7747 | unsigned long next_balance = jiffies + 60*HZ; |
| 7748 | int update_next_balance = 0; |
Jason Low | f48627e | 2013-09-13 11:26:53 -0700 | [diff] [blame] | 7749 | int need_serialize, need_decay = 0; |
| 7750 | u64 max_cost = 0; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7751 | |
Paul Turner | 48a1675 | 2012-10-04 13:18:31 +0200 | [diff] [blame] | 7752 | update_blocked_averages(cpu); |
Peter Zijlstra | 2069dd7 | 2010-11-15 15:47:00 -0800 | [diff] [blame] | 7753 | |
Peter Zijlstra | dce840a | 2011-04-07 14:09:50 +0200 | [diff] [blame] | 7754 | rcu_read_lock(); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7755 | for_each_domain(cpu, sd) { |
Jason Low | f48627e | 2013-09-13 11:26:53 -0700 | [diff] [blame] | 7756 | /* |
| 7757 | * Decay the newidle max times here because this is a regular |
| 7758 | * visit to all the domains. Decay ~1% per second. |
| 7759 | */ |
| 7760 | if (time_after(jiffies, sd->next_decay_max_lb_cost)) { |
| 7761 | sd->max_newidle_lb_cost = |
| 7762 | (sd->max_newidle_lb_cost * 253) / 256; |
| 7763 | sd->next_decay_max_lb_cost = jiffies + HZ; |
| 7764 | need_decay = 1; |
| 7765 | } |
| 7766 | max_cost += sd->max_newidle_lb_cost; |
| 7767 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7768 | if (!(sd->flags & SD_LOAD_BALANCE)) |
| 7769 | continue; |
| 7770 | |
Jason Low | f48627e | 2013-09-13 11:26:53 -0700 | [diff] [blame] | 7771 | /* |
| 7772 | * Stop the load balance at this level. There is another |
| 7773 | * CPU in our sched group which is doing load balancing more |
| 7774 | * actively. |
| 7775 | */ |
| 7776 | if (!continue_balancing) { |
| 7777 | if (need_decay) |
| 7778 | continue; |
| 7779 | break; |
| 7780 | } |
| 7781 | |
Jason Low | 52a08ef | 2014-05-08 17:49:22 -0700 | [diff] [blame] | 7782 | interval = get_sd_balance_interval(sd, idle != CPU_IDLE); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7783 | |
| 7784 | need_serialize = sd->flags & SD_SERIALIZE; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7785 | if (need_serialize) { |
| 7786 | if (!spin_trylock(&balancing)) |
| 7787 | goto out; |
| 7788 | } |
| 7789 | |
| 7790 | if (time_after_eq(jiffies, sd->last_balance + interval)) { |
Joonsoo Kim | 23f0d20 | 2013-08-06 17:36:42 +0900 | [diff] [blame] | 7791 | if (load_balance(cpu, rq, sd, idle, &continue_balancing)) { |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7792 | /* |
Peter Zijlstra | 6263322 | 2013-08-19 12:41:09 +0200 | [diff] [blame] | 7793 | * The LBF_DST_PINNED logic could have changed |
Joonsoo Kim | de5eb2d | 2013-04-23 17:27:38 +0900 | [diff] [blame] | 7794 | * env->dst_cpu, so we can't know our idle |
| 7795 | * state even if we migrated tasks. Update it. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7796 | */ |
Joonsoo Kim | de5eb2d | 2013-04-23 17:27:38 +0900 | [diff] [blame] | 7797 | idle = idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE; |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7798 | } |
| 7799 | sd->last_balance = jiffies; |
Jason Low | 52a08ef | 2014-05-08 17:49:22 -0700 | [diff] [blame] | 7800 | interval = get_sd_balance_interval(sd, idle != CPU_IDLE); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7801 | } |
| 7802 | if (need_serialize) |
| 7803 | spin_unlock(&balancing); |
| 7804 | out: |
| 7805 | if (time_after(next_balance, sd->last_balance + interval)) { |
| 7806 | next_balance = sd->last_balance + interval; |
| 7807 | update_next_balance = 1; |
| 7808 | } |
Jason Low | f48627e | 2013-09-13 11:26:53 -0700 | [diff] [blame] | 7809 | } |
| 7810 | if (need_decay) { |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7811 | /* |
Jason Low | f48627e | 2013-09-13 11:26:53 -0700 | [diff] [blame] | 7812 | * Ensure the rq-wide value also decays but keep it at a |
| 7813 | * reasonable floor to avoid funnies with rq->avg_idle. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7814 | */ |
Jason Low | f48627e | 2013-09-13 11:26:53 -0700 | [diff] [blame] | 7815 | rq->max_idle_balance_cost = |
| 7816 | max((u64)sysctl_sched_migration_cost, max_cost); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7817 | } |
Peter Zijlstra | dce840a | 2011-04-07 14:09:50 +0200 | [diff] [blame] | 7818 | rcu_read_unlock(); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7819 | |
| 7820 | /* |
| 7821 | * next_balance will be updated only when there is a need. |
| 7822 | * When the cpu is attached to null domain for ex, it will not be |
| 7823 | * updated. |
| 7824 | */ |
| 7825 | if (likely(update_next_balance)) |
| 7826 | rq->next_balance = next_balance; |
| 7827 | } |
| 7828 | |
Frederic Weisbecker | 3451d02 | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 7829 | #ifdef CONFIG_NO_HZ_COMMON |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7830 | /* |
Frederic Weisbecker | 3451d02 | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 7831 | * In CONFIG_NO_HZ_COMMON case, the idle balance kickee will do the |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7832 | * rebalancing for all the cpus for whom scheduler ticks are stopped. |
| 7833 | */ |
Daniel Lezcano | 208cb16 | 2014-01-06 12:34:44 +0100 | [diff] [blame] | 7834 | static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7835 | { |
Daniel Lezcano | 208cb16 | 2014-01-06 12:34:44 +0100 | [diff] [blame] | 7836 | int this_cpu = this_rq->cpu; |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7837 | struct rq *rq; |
| 7838 | int balance_cpu; |
| 7839 | |
Suresh Siddha | 1c792db | 2011-12-01 17:07:32 -0800 | [diff] [blame] | 7840 | if (idle != CPU_IDLE || |
| 7841 | !test_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu))) |
| 7842 | goto end; |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7843 | |
| 7844 | for_each_cpu(balance_cpu, nohz.idle_cpus_mask) { |
Suresh Siddha | 8a6d42d | 2011-12-06 11:19:37 -0800 | [diff] [blame] | 7845 | if (balance_cpu == this_cpu || !idle_cpu(balance_cpu)) |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7846 | continue; |
| 7847 | |
| 7848 | /* |
| 7849 | * If this cpu gets work to do, stop the load balancing |
| 7850 | * work being done for other cpus. Next load |
| 7851 | * balancing owner will pick it up. |
| 7852 | */ |
Suresh Siddha | 1c792db | 2011-12-01 17:07:32 -0800 | [diff] [blame] | 7853 | if (need_resched()) |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7854 | break; |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7855 | |
Vincent Guittot | 5ed4f1d | 2012-09-13 06:11:26 +0200 | [diff] [blame] | 7856 | rq = cpu_rq(balance_cpu); |
| 7857 | |
Tim Chen | ed61bbc | 2014-05-20 14:39:27 -0700 | [diff] [blame] | 7858 | /* |
| 7859 | * If time for next balance is due, |
| 7860 | * do the balance. |
| 7861 | */ |
| 7862 | if (time_after_eq(jiffies, rq->next_balance)) { |
| 7863 | raw_spin_lock_irq(&rq->lock); |
| 7864 | update_rq_clock(rq); |
| 7865 | update_idle_cpu_load(rq); |
| 7866 | raw_spin_unlock_irq(&rq->lock); |
| 7867 | rebalance_domains(rq, CPU_IDLE); |
| 7868 | } |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7869 | |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7870 | if (time_after(this_rq->next_balance, rq->next_balance)) |
| 7871 | this_rq->next_balance = rq->next_balance; |
| 7872 | } |
| 7873 | nohz.next_balance = this_rq->next_balance; |
Suresh Siddha | 1c792db | 2011-12-01 17:07:32 -0800 | [diff] [blame] | 7874 | end: |
| 7875 | clear_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu)); |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7876 | } |
| 7877 | |
| 7878 | /* |
Suresh Siddha | 0b005cf | 2011-12-01 17:07:34 -0800 | [diff] [blame] | 7879 | * Current heuristic for kicking the idle load balancer in the presence |
Vincent Guittot | 1aaf90a | 2015-02-27 16:54:14 +0100 | [diff] [blame] | 7880 | * of an idle cpu in the system. |
Suresh Siddha | 0b005cf | 2011-12-01 17:07:34 -0800 | [diff] [blame] | 7881 | * - This rq has more than one task. |
Vincent Guittot | 1aaf90a | 2015-02-27 16:54:14 +0100 | [diff] [blame] | 7882 | * - This rq has at least one CFS task and the capacity of the CPU is |
| 7883 | * significantly reduced because of RT tasks or IRQs. |
| 7884 | * - At parent of LLC scheduler domain level, this cpu's scheduler group has |
| 7885 | * multiple busy cpu. |
Suresh Siddha | 0b005cf | 2011-12-01 17:07:34 -0800 | [diff] [blame] | 7886 | * - For SD_ASYM_PACKING, if the lower numbered cpu's in the scheduler |
| 7887 | * domain span are idle. |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7888 | */ |
Vincent Guittot | 1aaf90a | 2015-02-27 16:54:14 +0100 | [diff] [blame] | 7889 | static inline bool nohz_kick_needed(struct rq *rq) |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7890 | { |
| 7891 | unsigned long now = jiffies; |
Suresh Siddha | 0b005cf | 2011-12-01 17:07:34 -0800 | [diff] [blame] | 7892 | struct sched_domain *sd; |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 7893 | struct sched_group_capacity *sgc; |
Daniel Lezcano | 4a72562 | 2014-01-06 12:34:39 +0100 | [diff] [blame] | 7894 | int nr_busy, cpu = rq->cpu; |
Vincent Guittot | 1aaf90a | 2015-02-27 16:54:14 +0100 | [diff] [blame] | 7895 | bool kick = false; |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7896 | |
Daniel Lezcano | 4a72562 | 2014-01-06 12:34:39 +0100 | [diff] [blame] | 7897 | if (unlikely(rq->idle_balance)) |
Vincent Guittot | 1aaf90a | 2015-02-27 16:54:14 +0100 | [diff] [blame] | 7898 | return false; |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7899 | |
Suresh Siddha | 1c792db | 2011-12-01 17:07:32 -0800 | [diff] [blame] | 7900 | /* |
| 7901 | * We may be recently in ticked or tickless idle mode. At the first |
| 7902 | * busy tick after returning from idle, we will update the busy stats. |
| 7903 | */ |
Suresh Siddha | 69e1e81 | 2011-12-01 17:07:33 -0800 | [diff] [blame] | 7904 | set_cpu_sd_state_busy(); |
Alex Shi | c1cc017 | 2012-09-10 15:10:58 +0800 | [diff] [blame] | 7905 | nohz_balance_exit_idle(cpu); |
Suresh Siddha | 0b005cf | 2011-12-01 17:07:34 -0800 | [diff] [blame] | 7906 | |
| 7907 | /* |
| 7908 | * None are in tickless mode and hence no need for NOHZ idle load |
| 7909 | * balancing. |
| 7910 | */ |
| 7911 | if (likely(!atomic_read(&nohz.nr_cpus))) |
Vincent Guittot | 1aaf90a | 2015-02-27 16:54:14 +0100 | [diff] [blame] | 7912 | return false; |
Suresh Siddha | 1c792db | 2011-12-01 17:07:32 -0800 | [diff] [blame] | 7913 | |
| 7914 | if (time_before(now, nohz.next_balance)) |
Vincent Guittot | 1aaf90a | 2015-02-27 16:54:14 +0100 | [diff] [blame] | 7915 | return false; |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7916 | |
Suresh Siddha | 0b005cf | 2011-12-01 17:07:34 -0800 | [diff] [blame] | 7917 | if (rq->nr_running >= 2) |
Vincent Guittot | 1aaf90a | 2015-02-27 16:54:14 +0100 | [diff] [blame] | 7918 | return true; |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7919 | |
Peter Zijlstra | 067491b | 2011-12-07 14:32:08 +0100 | [diff] [blame] | 7920 | rcu_read_lock(); |
Preeti U Murthy | 37dc6b5 | 2013-10-30 08:42:52 +0530 | [diff] [blame] | 7921 | sd = rcu_dereference(per_cpu(sd_busy, cpu)); |
Preeti U Murthy | 37dc6b5 | 2013-10-30 08:42:52 +0530 | [diff] [blame] | 7922 | if (sd) { |
Nicolas Pitre | 63b2ca3 | 2014-05-26 18:19:37 -0400 | [diff] [blame] | 7923 | sgc = sd->groups->sgc; |
| 7924 | nr_busy = atomic_read(&sgc->nr_busy_cpus); |
Preeti U Murthy | 37dc6b5 | 2013-10-30 08:42:52 +0530 | [diff] [blame] | 7925 | |
Vincent Guittot | 1aaf90a | 2015-02-27 16:54:14 +0100 | [diff] [blame] | 7926 | if (nr_busy > 1) { |
| 7927 | kick = true; |
| 7928 | goto unlock; |
| 7929 | } |
| 7930 | |
| 7931 | } |
| 7932 | |
| 7933 | sd = rcu_dereference(rq->sd); |
| 7934 | if (sd) { |
| 7935 | if ((rq->cfs.h_nr_running >= 1) && |
| 7936 | check_cpu_capacity(rq, sd)) { |
| 7937 | kick = true; |
| 7938 | goto unlock; |
| 7939 | } |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7940 | } |
Preeti U Murthy | 37dc6b5 | 2013-10-30 08:42:52 +0530 | [diff] [blame] | 7941 | |
| 7942 | sd = rcu_dereference(per_cpu(sd_asym, cpu)); |
Preeti U Murthy | 37dc6b5 | 2013-10-30 08:42:52 +0530 | [diff] [blame] | 7943 | if (sd && (cpumask_first_and(nohz.idle_cpus_mask, |
Vincent Guittot | 1aaf90a | 2015-02-27 16:54:14 +0100 | [diff] [blame] | 7944 | sched_domain_span(sd)) < cpu)) { |
| 7945 | kick = true; |
| 7946 | goto unlock; |
| 7947 | } |
Preeti U Murthy | 37dc6b5 | 2013-10-30 08:42:52 +0530 | [diff] [blame] | 7948 | |
Vincent Guittot | 1aaf90a | 2015-02-27 16:54:14 +0100 | [diff] [blame] | 7949 | unlock: |
Peter Zijlstra | 067491b | 2011-12-07 14:32:08 +0100 | [diff] [blame] | 7950 | rcu_read_unlock(); |
Vincent Guittot | 1aaf90a | 2015-02-27 16:54:14 +0100 | [diff] [blame] | 7951 | return kick; |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7952 | } |
| 7953 | #else |
Daniel Lezcano | 208cb16 | 2014-01-06 12:34:44 +0100 | [diff] [blame] | 7954 | static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) { } |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7955 | #endif |
| 7956 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7957 | /* |
| 7958 | * run_rebalance_domains is triggered when needed from the scheduler tick. |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7959 | * Also triggered for nohz idle balancing (with nohz_balancing_kick set). |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7960 | */ |
| 7961 | static void run_rebalance_domains(struct softirq_action *h) |
| 7962 | { |
Daniel Lezcano | 208cb16 | 2014-01-06 12:34:44 +0100 | [diff] [blame] | 7963 | struct rq *this_rq = this_rq(); |
Suresh Siddha | 6eb57e0 | 2011-10-03 15:09:01 -0700 | [diff] [blame] | 7964 | enum cpu_idle_type idle = this_rq->idle_balance ? |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7965 | CPU_IDLE : CPU_NOT_IDLE; |
| 7966 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7967 | /* |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7968 | * If this cpu has a pending nohz_balance_kick, then do the |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7969 | * balancing on behalf of the other idle cpus whose ticks are |
Preeti U Murthy | d4573c3 | 2015-03-26 18:32:44 +0530 | [diff] [blame] | 7970 | * stopped. Do nohz_idle_balance *before* rebalance_domains to |
| 7971 | * give the idle cpus a chance to load balance. Else we may |
| 7972 | * load balance only within the local sched_domain hierarchy |
| 7973 | * and abort nohz_idle_balance altogether if we pull some load. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7974 | */ |
Daniel Lezcano | 208cb16 | 2014-01-06 12:34:44 +0100 | [diff] [blame] | 7975 | nohz_idle_balance(this_rq, idle); |
Preeti U Murthy | d4573c3 | 2015-03-26 18:32:44 +0530 | [diff] [blame] | 7976 | rebalance_domains(this_rq, idle); |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7977 | } |
| 7978 | |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7979 | /* |
| 7980 | * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7981 | */ |
Daniel Lezcano | 7caff66 | 2014-01-06 12:34:38 +0100 | [diff] [blame] | 7982 | void trigger_load_balance(struct rq *rq) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7983 | { |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7984 | /* Don't need to rebalance while attached to NULL domain */ |
Daniel Lezcano | c726099 | 2014-01-06 12:34:45 +0100 | [diff] [blame] | 7985 | if (unlikely(on_null_domain(rq))) |
| 7986 | return; |
| 7987 | |
| 7988 | if (time_after_eq(jiffies, rq->next_balance)) |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7989 | raise_softirq(SCHED_SOFTIRQ); |
Frederic Weisbecker | 3451d02 | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 7990 | #ifdef CONFIG_NO_HZ_COMMON |
Daniel Lezcano | c726099 | 2014-01-06 12:34:45 +0100 | [diff] [blame] | 7991 | if (nohz_kick_needed(rq)) |
Daniel Lezcano | 0aeeeeb | 2014-01-06 12:34:42 +0100 | [diff] [blame] | 7992 | nohz_balancer_kick(); |
Venkatesh Pallipadi | 83cd4fe | 2010-05-21 17:09:41 -0700 | [diff] [blame] | 7993 | #endif |
Peter Zijlstra | 1e3c88b | 2009-12-17 17:00:43 +0100 | [diff] [blame] | 7994 | } |
| 7995 | |
Christian Ehrhardt | 0bcdcf2 | 2009-11-30 12:16:46 +0100 | [diff] [blame] | 7996 | static void rq_online_fair(struct rq *rq) |
| 7997 | { |
| 7998 | update_sysctl(); |
Kirill Tkhai | 0e59bda | 2014-06-25 12:19:42 +0400 | [diff] [blame] | 7999 | |
| 8000 | update_runtime_enabled(rq); |
Christian Ehrhardt | 0bcdcf2 | 2009-11-30 12:16:46 +0100 | [diff] [blame] | 8001 | } |
| 8002 | |
| 8003 | static void rq_offline_fair(struct rq *rq) |
| 8004 | { |
| 8005 | update_sysctl(); |
Peter Boonstoppel | a4c96ae | 2012-08-09 15:34:47 -0700 | [diff] [blame] | 8006 | |
| 8007 | /* Ensure any throttled groups are reachable by pick_next_task */ |
| 8008 | unthrottle_offline_cfs_rqs(rq); |
Christian Ehrhardt | 0bcdcf2 | 2009-11-30 12:16:46 +0100 | [diff] [blame] | 8009 | } |
| 8010 | |
Dhaval Giani | 55e12e5 | 2008-06-24 23:39:43 +0530 | [diff] [blame] | 8011 | #endif /* CONFIG_SMP */ |
Peter Williams | e1d1484 | 2007-10-24 18:23:51 +0200 | [diff] [blame] | 8012 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8013 | /* |
| 8014 | * scheduler tick hitting a task of our scheduling class: |
| 8015 | */ |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 8016 | static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8017 | { |
| 8018 | struct cfs_rq *cfs_rq; |
| 8019 | struct sched_entity *se = &curr->se; |
| 8020 | |
| 8021 | for_each_sched_entity(se) { |
| 8022 | cfs_rq = cfs_rq_of(se); |
Peter Zijlstra | 8f4d37e | 2008-01-25 21:08:29 +0100 | [diff] [blame] | 8023 | entity_tick(cfs_rq, se, queued); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8024 | } |
Ben Segall | 18bf280 | 2012-10-04 12:51:20 +0200 | [diff] [blame] | 8025 | |
Dave Kleikamp | 10e84b9 | 2013-07-31 13:53:35 -0700 | [diff] [blame] | 8026 | if (numabalancing_enabled) |
Peter Zijlstra | cbee9f8 | 2012-10-25 14:16:43 +0200 | [diff] [blame] | 8027 | task_tick_numa(rq, curr); |
Linus Torvalds | 3d59eeb | 2012-12-16 14:33:25 -0800 | [diff] [blame] | 8028 | |
Ben Segall | 18bf280 | 2012-10-04 12:51:20 +0200 | [diff] [blame] | 8029 | update_rq_runnable_avg(rq, 1); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8030 | } |
| 8031 | |
| 8032 | /* |
Peter Zijlstra | cd29fe6 | 2009-11-27 17:32:46 +0100 | [diff] [blame] | 8033 | * called on fork with the child task as argument from the parent's context |
| 8034 | * - child not yet on the tasklist |
| 8035 | * - preemption disabled |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8036 | */ |
Peter Zijlstra | cd29fe6 | 2009-11-27 17:32:46 +0100 | [diff] [blame] | 8037 | static void task_fork_fair(struct task_struct *p) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8038 | { |
Daisuke Nishimura | 4fc420c | 2011-12-15 14:36:55 +0900 | [diff] [blame] | 8039 | struct cfs_rq *cfs_rq; |
| 8040 | struct sched_entity *se = &p->se, *curr; |
Ingo Molnar | 00bf7bf | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 8041 | int this_cpu = smp_processor_id(); |
Peter Zijlstra | cd29fe6 | 2009-11-27 17:32:46 +0100 | [diff] [blame] | 8042 | struct rq *rq = this_rq(); |
| 8043 | unsigned long flags; |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8044 | |
Thomas Gleixner | 05fa785 | 2009-11-17 14:28:38 +0100 | [diff] [blame] | 8045 | raw_spin_lock_irqsave(&rq->lock, flags); |
Peter Zijlstra | cd29fe6 | 2009-11-27 17:32:46 +0100 | [diff] [blame] | 8046 | |
Peter Zijlstra | 861d034 | 2010-08-19 13:31:43 +0200 | [diff] [blame] | 8047 | update_rq_clock(rq); |
| 8048 | |
Daisuke Nishimura | 4fc420c | 2011-12-15 14:36:55 +0900 | [diff] [blame] | 8049 | cfs_rq = task_cfs_rq(current); |
| 8050 | curr = cfs_rq->curr; |
| 8051 | |
Daisuke Nishimura | 6c9a27f | 2013-09-10 18:16:36 +0900 | [diff] [blame] | 8052 | /* |
| 8053 | * Not only the cpu but also the task_group of the parent might have |
| 8054 | * been changed after parent->se.parent,cfs_rq were copied to |
| 8055 | * child->se.parent,cfs_rq. So call __set_task_cpu() to make those |
| 8056 | * of child point to valid ones. |
| 8057 | */ |
| 8058 | rcu_read_lock(); |
| 8059 | __set_task_cpu(p, this_cpu); |
| 8060 | rcu_read_unlock(); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8061 | |
Ting Yang | 7109c442 | 2007-08-28 12:53:24 +0200 | [diff] [blame] | 8062 | update_curr(cfs_rq); |
Peter Zijlstra | cd29fe6 | 2009-11-27 17:32:46 +0100 | [diff] [blame] | 8063 | |
Mike Galbraith | b5d9d73 | 2009-09-08 11:12:28 +0200 | [diff] [blame] | 8064 | if (curr) |
| 8065 | se->vruntime = curr->vruntime; |
Peter Zijlstra | aeb73b0 | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 8066 | place_entity(cfs_rq, se, 1); |
Peter Zijlstra | 4d78e7b | 2007-10-15 17:00:04 +0200 | [diff] [blame] | 8067 | |
Peter Zijlstra | cd29fe6 | 2009-11-27 17:32:46 +0100 | [diff] [blame] | 8068 | if (sysctl_sched_child_runs_first && curr && entity_before(curr, se)) { |
Dmitry Adamushko | 87fefa3 | 2007-10-15 17:00:08 +0200 | [diff] [blame] | 8069 | /* |
Ingo Molnar | edcb60a | 2007-10-15 17:00:08 +0200 | [diff] [blame] | 8070 | * Upon rescheduling, sched_class::put_prev_task() will place |
| 8071 | * 'current' within the tree based on its new key value. |
| 8072 | */ |
Peter Zijlstra | 4d78e7b | 2007-10-15 17:00:04 +0200 | [diff] [blame] | 8073 | swap(curr->vruntime, se->vruntime); |
Kirill Tkhai | 8875125 | 2014-06-29 00:03:57 +0400 | [diff] [blame] | 8074 | resched_curr(rq); |
Peter Zijlstra | 4d78e7b | 2007-10-15 17:00:04 +0200 | [diff] [blame] | 8075 | } |
| 8076 | |
Peter Zijlstra | 88ec22d | 2009-12-16 18:04:41 +0100 | [diff] [blame] | 8077 | se->vruntime -= cfs_rq->min_vruntime; |
| 8078 | |
Thomas Gleixner | 05fa785 | 2009-11-17 14:28:38 +0100 | [diff] [blame] | 8079 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8080 | } |
| 8081 | |
Steven Rostedt | cb46984 | 2008-01-25 21:08:22 +0100 | [diff] [blame] | 8082 | /* |
| 8083 | * Priority of the task has changed. Check to see if we preempt |
| 8084 | * the current task. |
| 8085 | */ |
Peter Zijlstra | da7a735 | 2011-01-17 17:03:27 +0100 | [diff] [blame] | 8086 | static void |
| 8087 | prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio) |
Steven Rostedt | cb46984 | 2008-01-25 21:08:22 +0100 | [diff] [blame] | 8088 | { |
Kirill Tkhai | da0c1e6 | 2014-08-20 13:47:32 +0400 | [diff] [blame] | 8089 | if (!task_on_rq_queued(p)) |
Peter Zijlstra | da7a735 | 2011-01-17 17:03:27 +0100 | [diff] [blame] | 8090 | return; |
| 8091 | |
Steven Rostedt | cb46984 | 2008-01-25 21:08:22 +0100 | [diff] [blame] | 8092 | /* |
| 8093 | * Reschedule if we are currently running on this runqueue and |
| 8094 | * our priority decreased, or if we are not currently running on |
| 8095 | * this runqueue and our priority is higher than the current's |
| 8096 | */ |
Peter Zijlstra | da7a735 | 2011-01-17 17:03:27 +0100 | [diff] [blame] | 8097 | if (rq->curr == p) { |
Steven Rostedt | cb46984 | 2008-01-25 21:08:22 +0100 | [diff] [blame] | 8098 | if (p->prio > oldprio) |
Kirill Tkhai | 8875125 | 2014-06-29 00:03:57 +0400 | [diff] [blame] | 8099 | resched_curr(rq); |
Steven Rostedt | cb46984 | 2008-01-25 21:08:22 +0100 | [diff] [blame] | 8100 | } else |
Peter Zijlstra | 15afe09 | 2008-09-20 23:38:02 +0200 | [diff] [blame] | 8101 | check_preempt_curr(rq, p, 0); |
Steven Rostedt | cb46984 | 2008-01-25 21:08:22 +0100 | [diff] [blame] | 8102 | } |
| 8103 | |
Peter Zijlstra | da7a735 | 2011-01-17 17:03:27 +0100 | [diff] [blame] | 8104 | static void switched_from_fair(struct rq *rq, struct task_struct *p) |
| 8105 | { |
| 8106 | struct sched_entity *se = &p->se; |
| 8107 | struct cfs_rq *cfs_rq = cfs_rq_of(se); |
| 8108 | |
| 8109 | /* |
George McCollister | 791c9e0 | 2014-02-18 17:56:51 -0600 | [diff] [blame] | 8110 | * Ensure the task's vruntime is normalized, so that when it's |
Peter Zijlstra | da7a735 | 2011-01-17 17:03:27 +0100 | [diff] [blame] | 8111 | * switched back to the fair class the enqueue_entity(.flags=0) will |
| 8112 | * do the right thing. |
| 8113 | * |
Kirill Tkhai | da0c1e6 | 2014-08-20 13:47:32 +0400 | [diff] [blame] | 8114 | * If it's queued, then the dequeue_entity(.flags=0) will already |
| 8115 | * have normalized the vruntime, if it's !queued, then only when |
Peter Zijlstra | da7a735 | 2011-01-17 17:03:27 +0100 | [diff] [blame] | 8116 | * the task is sleeping will it still have non-normalized vruntime. |
| 8117 | */ |
Kirill Tkhai | da0c1e6 | 2014-08-20 13:47:32 +0400 | [diff] [blame] | 8118 | if (!task_on_rq_queued(p) && p->state != TASK_RUNNING) { |
Peter Zijlstra | da7a735 | 2011-01-17 17:03:27 +0100 | [diff] [blame] | 8119 | /* |
| 8120 | * Fix up our vruntime so that the current sleep doesn't |
| 8121 | * cause 'unlimited' sleep bonus. |
| 8122 | */ |
| 8123 | place_entity(cfs_rq, se, 0); |
| 8124 | se->vruntime -= cfs_rq->min_vruntime; |
| 8125 | } |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 8126 | |
Alex Shi | 141965c | 2013-06-26 13:05:39 +0800 | [diff] [blame] | 8127 | #ifdef CONFIG_SMP |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 8128 | /* |
| 8129 | * Remove our load from contribution when we leave sched_fair |
| 8130 | * and ensure we don't carry in an old decay_count if we |
| 8131 | * switch back. |
| 8132 | */ |
Kirill Tkhai | 87e3c8a | 2013-07-21 04:32:07 +0400 | [diff] [blame] | 8133 | if (se->avg.decay_count) { |
| 8134 | __synchronize_entity_decay(se); |
| 8135 | subtract_blocked_load_contrib(cfs_rq, se->avg.load_avg_contrib); |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 8136 | } |
| 8137 | #endif |
Peter Zijlstra | da7a735 | 2011-01-17 17:03:27 +0100 | [diff] [blame] | 8138 | } |
| 8139 | |
Steven Rostedt | cb46984 | 2008-01-25 21:08:22 +0100 | [diff] [blame] | 8140 | /* |
| 8141 | * We switched to the sched_fair class. |
| 8142 | */ |
Peter Zijlstra | da7a735 | 2011-01-17 17:03:27 +0100 | [diff] [blame] | 8143 | static void switched_to_fair(struct rq *rq, struct task_struct *p) |
Steven Rostedt | cb46984 | 2008-01-25 21:08:22 +0100 | [diff] [blame] | 8144 | { |
Michael wang | eb7a59b | 2014-02-20 11:14:53 +0800 | [diff] [blame] | 8145 | #ifdef CONFIG_FAIR_GROUP_SCHED |
Kirill Tkhai | f36c019 | 2014-08-06 12:06:01 +0400 | [diff] [blame] | 8146 | struct sched_entity *se = &p->se; |
Michael wang | eb7a59b | 2014-02-20 11:14:53 +0800 | [diff] [blame] | 8147 | /* |
| 8148 | * Since the real-depth could have been changed (only FAIR |
| 8149 | * class maintain depth value), reset depth properly. |
| 8150 | */ |
| 8151 | se->depth = se->parent ? se->parent->depth + 1 : 0; |
| 8152 | #endif |
Kirill Tkhai | da0c1e6 | 2014-08-20 13:47:32 +0400 | [diff] [blame] | 8153 | if (!task_on_rq_queued(p)) |
Peter Zijlstra | da7a735 | 2011-01-17 17:03:27 +0100 | [diff] [blame] | 8154 | return; |
| 8155 | |
Steven Rostedt | cb46984 | 2008-01-25 21:08:22 +0100 | [diff] [blame] | 8156 | /* |
| 8157 | * We were most likely switched from sched_rt, so |
| 8158 | * kick off the schedule if running, otherwise just see |
| 8159 | * if we can still preempt the current task. |
| 8160 | */ |
Peter Zijlstra | da7a735 | 2011-01-17 17:03:27 +0100 | [diff] [blame] | 8161 | if (rq->curr == p) |
Kirill Tkhai | 8875125 | 2014-06-29 00:03:57 +0400 | [diff] [blame] | 8162 | resched_curr(rq); |
Steven Rostedt | cb46984 | 2008-01-25 21:08:22 +0100 | [diff] [blame] | 8163 | else |
Peter Zijlstra | 15afe09 | 2008-09-20 23:38:02 +0200 | [diff] [blame] | 8164 | check_preempt_curr(rq, p, 0); |
Steven Rostedt | cb46984 | 2008-01-25 21:08:22 +0100 | [diff] [blame] | 8165 | } |
| 8166 | |
Srivatsa Vaddagiri | 83b699e | 2007-10-15 17:00:08 +0200 | [diff] [blame] | 8167 | /* Account for a task changing its policy or group. |
| 8168 | * |
| 8169 | * This routine is mostly called to set cfs_rq->curr field when a task |
| 8170 | * migrates between groups/classes. |
| 8171 | */ |
| 8172 | static void set_curr_task_fair(struct rq *rq) |
| 8173 | { |
| 8174 | struct sched_entity *se = &rq->curr->se; |
| 8175 | |
Paul Turner | ec12cb7 | 2011-07-21 09:43:30 -0700 | [diff] [blame] | 8176 | for_each_sched_entity(se) { |
| 8177 | struct cfs_rq *cfs_rq = cfs_rq_of(se); |
| 8178 | |
| 8179 | set_next_entity(cfs_rq, se); |
| 8180 | /* ensure bandwidth has been allocated on our new cfs_rq */ |
| 8181 | account_cfs_rq_runtime(cfs_rq, 0); |
| 8182 | } |
Srivatsa Vaddagiri | 83b699e | 2007-10-15 17:00:08 +0200 | [diff] [blame] | 8183 | } |
| 8184 | |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8185 | void init_cfs_rq(struct cfs_rq *cfs_rq) |
| 8186 | { |
| 8187 | cfs_rq->tasks_timeline = RB_ROOT; |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8188 | cfs_rq->min_vruntime = (u64)(-(1LL << 20)); |
| 8189 | #ifndef CONFIG_64BIT |
| 8190 | cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime; |
| 8191 | #endif |
Alex Shi | 141965c | 2013-06-26 13:05:39 +0800 | [diff] [blame] | 8192 | #ifdef CONFIG_SMP |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 8193 | atomic64_set(&cfs_rq->decay_counter, 1); |
Alex Shi | 2509940 | 2013-06-20 10:18:55 +0800 | [diff] [blame] | 8194 | atomic_long_set(&cfs_rq->removed_load, 0); |
Paul Turner | 9ee474f | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 8195 | #endif |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8196 | } |
| 8197 | |
Peter Zijlstra | 810b381 | 2008-02-29 15:21:01 -0500 | [diff] [blame] | 8198 | #ifdef CONFIG_FAIR_GROUP_SCHED |
Kirill Tkhai | da0c1e6 | 2014-08-20 13:47:32 +0400 | [diff] [blame] | 8199 | static void task_move_group_fair(struct task_struct *p, int queued) |
Peter Zijlstra | 810b381 | 2008-02-29 15:21:01 -0500 | [diff] [blame] | 8200 | { |
Peter Zijlstra | fed14d4 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 8201 | struct sched_entity *se = &p->se; |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 8202 | struct cfs_rq *cfs_rq; |
Peter Zijlstra | fed14d4 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 8203 | |
Peter Zijlstra | b2b5ce0 | 2010-10-15 15:24:15 +0200 | [diff] [blame] | 8204 | /* |
| 8205 | * If the task was not on the rq at the time of this cgroup movement |
| 8206 | * it must have been asleep, sleeping tasks keep their ->vruntime |
| 8207 | * absolute on their old rq until wakeup (needed for the fair sleeper |
| 8208 | * bonus in place_entity()). |
| 8209 | * |
| 8210 | * If it was on the rq, we've just 'preempted' it, which does convert |
| 8211 | * ->vruntime to a relative base. |
| 8212 | * |
| 8213 | * Make sure both cases convert their relative position when migrating |
| 8214 | * to another cgroup's rq. This does somewhat interfere with the |
| 8215 | * fair sleeper stuff for the first placement, but who cares. |
| 8216 | */ |
Daisuke Nishimura | 7ceff01 | 2011-12-15 14:36:07 +0900 | [diff] [blame] | 8217 | /* |
Kirill Tkhai | da0c1e6 | 2014-08-20 13:47:32 +0400 | [diff] [blame] | 8218 | * When !queued, vruntime of the task has usually NOT been normalized. |
Daisuke Nishimura | 7ceff01 | 2011-12-15 14:36:07 +0900 | [diff] [blame] | 8219 | * But there are some cases where it has already been normalized: |
| 8220 | * |
| 8221 | * - Moving a forked child which is waiting for being woken up by |
| 8222 | * wake_up_new_task(). |
Daisuke Nishimura | 62af378 | 2011-12-15 14:37:41 +0900 | [diff] [blame] | 8223 | * - Moving a task which has been woken up by try_to_wake_up() and |
| 8224 | * waiting for actually being woken up by sched_ttwu_pending(). |
Daisuke Nishimura | 7ceff01 | 2011-12-15 14:36:07 +0900 | [diff] [blame] | 8225 | * |
| 8226 | * To prevent boost or penalty in the new cfs_rq caused by delta |
| 8227 | * min_vruntime between the two cfs_rqs, we skip vruntime adjustment. |
| 8228 | */ |
Kirill Tkhai | da0c1e6 | 2014-08-20 13:47:32 +0400 | [diff] [blame] | 8229 | if (!queued && (!se->sum_exec_runtime || p->state == TASK_WAKING)) |
| 8230 | queued = 1; |
Daisuke Nishimura | 7ceff01 | 2011-12-15 14:36:07 +0900 | [diff] [blame] | 8231 | |
Kirill Tkhai | da0c1e6 | 2014-08-20 13:47:32 +0400 | [diff] [blame] | 8232 | if (!queued) |
Peter Zijlstra | fed14d4 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 8233 | se->vruntime -= cfs_rq_of(se)->min_vruntime; |
Peter Zijlstra | b2b5ce0 | 2010-10-15 15:24:15 +0200 | [diff] [blame] | 8234 | set_task_rq(p, task_cpu(p)); |
Peter Zijlstra | fed14d4 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 8235 | se->depth = se->parent ? se->parent->depth + 1 : 0; |
Kirill Tkhai | da0c1e6 | 2014-08-20 13:47:32 +0400 | [diff] [blame] | 8236 | if (!queued) { |
Peter Zijlstra | fed14d4 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 8237 | cfs_rq = cfs_rq_of(se); |
| 8238 | se->vruntime += cfs_rq->min_vruntime; |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 8239 | #ifdef CONFIG_SMP |
| 8240 | /* |
| 8241 | * migrate_task_rq_fair() will have removed our previous |
| 8242 | * contribution, but we must synchronize for ongoing future |
| 8243 | * decay. |
| 8244 | */ |
Peter Zijlstra | fed14d4 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 8245 | se->avg.decay_count = atomic64_read(&cfs_rq->decay_counter); |
| 8246 | cfs_rq->blocked_load_avg += se->avg.load_avg_contrib; |
Paul Turner | aff3e49 | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 8247 | #endif |
| 8248 | } |
Peter Zijlstra | 810b381 | 2008-02-29 15:21:01 -0500 | [diff] [blame] | 8249 | } |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8250 | |
| 8251 | void free_fair_sched_group(struct task_group *tg) |
| 8252 | { |
| 8253 | int i; |
| 8254 | |
| 8255 | destroy_cfs_bandwidth(tg_cfs_bandwidth(tg)); |
| 8256 | |
| 8257 | for_each_possible_cpu(i) { |
| 8258 | if (tg->cfs_rq) |
| 8259 | kfree(tg->cfs_rq[i]); |
| 8260 | if (tg->se) |
| 8261 | kfree(tg->se[i]); |
| 8262 | } |
| 8263 | |
| 8264 | kfree(tg->cfs_rq); |
| 8265 | kfree(tg->se); |
| 8266 | } |
| 8267 | |
| 8268 | int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) |
| 8269 | { |
| 8270 | struct cfs_rq *cfs_rq; |
| 8271 | struct sched_entity *se; |
| 8272 | int i; |
| 8273 | |
| 8274 | tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL); |
| 8275 | if (!tg->cfs_rq) |
| 8276 | goto err; |
| 8277 | tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL); |
| 8278 | if (!tg->se) |
| 8279 | goto err; |
| 8280 | |
| 8281 | tg->shares = NICE_0_LOAD; |
| 8282 | |
| 8283 | init_cfs_bandwidth(tg_cfs_bandwidth(tg)); |
| 8284 | |
| 8285 | for_each_possible_cpu(i) { |
| 8286 | cfs_rq = kzalloc_node(sizeof(struct cfs_rq), |
| 8287 | GFP_KERNEL, cpu_to_node(i)); |
| 8288 | if (!cfs_rq) |
| 8289 | goto err; |
| 8290 | |
| 8291 | se = kzalloc_node(sizeof(struct sched_entity), |
| 8292 | GFP_KERNEL, cpu_to_node(i)); |
| 8293 | if (!se) |
| 8294 | goto err_free_rq; |
| 8295 | |
| 8296 | init_cfs_rq(cfs_rq); |
| 8297 | init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]); |
| 8298 | } |
| 8299 | |
| 8300 | return 1; |
| 8301 | |
| 8302 | err_free_rq: |
| 8303 | kfree(cfs_rq); |
| 8304 | err: |
| 8305 | return 0; |
| 8306 | } |
| 8307 | |
| 8308 | void unregister_fair_sched_group(struct task_group *tg, int cpu) |
| 8309 | { |
| 8310 | struct rq *rq = cpu_rq(cpu); |
| 8311 | unsigned long flags; |
| 8312 | |
| 8313 | /* |
| 8314 | * Only empty task groups can be destroyed; so we can speculatively |
| 8315 | * check on_list without danger of it being re-added. |
| 8316 | */ |
| 8317 | if (!tg->cfs_rq[cpu]->on_list) |
| 8318 | return; |
| 8319 | |
| 8320 | raw_spin_lock_irqsave(&rq->lock, flags); |
| 8321 | list_del_leaf_cfs_rq(tg->cfs_rq[cpu]); |
| 8322 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
| 8323 | } |
| 8324 | |
| 8325 | void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq, |
| 8326 | struct sched_entity *se, int cpu, |
| 8327 | struct sched_entity *parent) |
| 8328 | { |
| 8329 | struct rq *rq = cpu_rq(cpu); |
| 8330 | |
| 8331 | cfs_rq->tg = tg; |
| 8332 | cfs_rq->rq = rq; |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8333 | init_cfs_rq_runtime(cfs_rq); |
| 8334 | |
| 8335 | tg->cfs_rq[cpu] = cfs_rq; |
| 8336 | tg->se[cpu] = se; |
| 8337 | |
| 8338 | /* se could be NULL for root_task_group */ |
| 8339 | if (!se) |
| 8340 | return; |
| 8341 | |
Peter Zijlstra | fed14d4 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 8342 | if (!parent) { |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8343 | se->cfs_rq = &rq->cfs; |
Peter Zijlstra | fed14d4 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 8344 | se->depth = 0; |
| 8345 | } else { |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8346 | se->cfs_rq = parent->my_q; |
Peter Zijlstra | fed14d4 | 2012-02-11 06:05:00 +0100 | [diff] [blame] | 8347 | se->depth = parent->depth + 1; |
| 8348 | } |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8349 | |
| 8350 | se->my_q = cfs_rq; |
Paul Turner | 0ac9b1c | 2013-10-16 11:16:27 -0700 | [diff] [blame] | 8351 | /* guarantee group entities always have weight */ |
| 8352 | update_load_set(&se->load, NICE_0_LOAD); |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8353 | se->parent = parent; |
| 8354 | } |
| 8355 | |
| 8356 | static DEFINE_MUTEX(shares_mutex); |
| 8357 | |
| 8358 | int sched_group_set_shares(struct task_group *tg, unsigned long shares) |
| 8359 | { |
| 8360 | int i; |
| 8361 | unsigned long flags; |
| 8362 | |
| 8363 | /* |
| 8364 | * We can't change the weight of the root cgroup. |
| 8365 | */ |
| 8366 | if (!tg->se[0]) |
| 8367 | return -EINVAL; |
| 8368 | |
| 8369 | shares = clamp(shares, scale_load(MIN_SHARES), scale_load(MAX_SHARES)); |
| 8370 | |
| 8371 | mutex_lock(&shares_mutex); |
| 8372 | if (tg->shares == shares) |
| 8373 | goto done; |
| 8374 | |
| 8375 | tg->shares = shares; |
| 8376 | for_each_possible_cpu(i) { |
| 8377 | struct rq *rq = cpu_rq(i); |
| 8378 | struct sched_entity *se; |
| 8379 | |
| 8380 | se = tg->se[i]; |
| 8381 | /* Propagate contribution to hierarchy */ |
| 8382 | raw_spin_lock_irqsave(&rq->lock, flags); |
Frederic Weisbecker | 71b1da4 | 2013-04-12 01:50:59 +0200 | [diff] [blame] | 8383 | |
| 8384 | /* Possible calls to update_curr() need rq clock */ |
| 8385 | update_rq_clock(rq); |
Linus Torvalds | 17bc14b | 2012-12-14 07:20:43 -0800 | [diff] [blame] | 8386 | for_each_sched_entity(se) |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8387 | update_cfs_shares(group_cfs_rq(se)); |
| 8388 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
| 8389 | } |
| 8390 | |
| 8391 | done: |
| 8392 | mutex_unlock(&shares_mutex); |
| 8393 | return 0; |
| 8394 | } |
| 8395 | #else /* CONFIG_FAIR_GROUP_SCHED */ |
| 8396 | |
| 8397 | void free_fair_sched_group(struct task_group *tg) { } |
| 8398 | |
| 8399 | int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) |
| 8400 | { |
| 8401 | return 1; |
| 8402 | } |
| 8403 | |
| 8404 | void unregister_fair_sched_group(struct task_group *tg, int cpu) { } |
| 8405 | |
| 8406 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
| 8407 | |
Peter Zijlstra | 810b381 | 2008-02-29 15:21:01 -0500 | [diff] [blame] | 8408 | |
H Hartley Sweeten | 6d686f4 | 2010-01-13 20:21:52 -0700 | [diff] [blame] | 8409 | static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task) |
Peter Williams | 0d721ce | 2009-09-21 01:31:53 +0000 | [diff] [blame] | 8410 | { |
| 8411 | struct sched_entity *se = &task->se; |
Peter Williams | 0d721ce | 2009-09-21 01:31:53 +0000 | [diff] [blame] | 8412 | unsigned int rr_interval = 0; |
| 8413 | |
| 8414 | /* |
| 8415 | * Time slice is 0 for SCHED_OTHER tasks that are on an otherwise |
| 8416 | * idle runqueue: |
| 8417 | */ |
Peter Williams | 0d721ce | 2009-09-21 01:31:53 +0000 | [diff] [blame] | 8418 | if (rq->cfs.load.weight) |
Zhu Yanhai | a59f4e0 | 2013-01-08 12:56:52 +0800 | [diff] [blame] | 8419 | rr_interval = NS_TO_JIFFIES(sched_slice(cfs_rq_of(se), se)); |
Peter Williams | 0d721ce | 2009-09-21 01:31:53 +0000 | [diff] [blame] | 8420 | |
| 8421 | return rr_interval; |
| 8422 | } |
| 8423 | |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8424 | /* |
| 8425 | * All the scheduling class methods: |
| 8426 | */ |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8427 | const struct sched_class fair_sched_class = { |
Ingo Molnar | 5522d5d | 2007-10-15 17:00:12 +0200 | [diff] [blame] | 8428 | .next = &idle_sched_class, |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8429 | .enqueue_task = enqueue_task_fair, |
| 8430 | .dequeue_task = dequeue_task_fair, |
| 8431 | .yield_task = yield_task_fair, |
Mike Galbraith | d95f412 | 2011-02-01 09:50:51 -0500 | [diff] [blame] | 8432 | .yield_to_task = yield_to_task_fair, |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8433 | |
Ingo Molnar | 2e09bf5 | 2007-10-15 17:00:05 +0200 | [diff] [blame] | 8434 | .check_preempt_curr = check_preempt_wakeup, |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8435 | |
| 8436 | .pick_next_task = pick_next_task_fair, |
| 8437 | .put_prev_task = put_prev_task_fair, |
| 8438 | |
Peter Williams | 681f3e6 | 2007-10-24 18:23:51 +0200 | [diff] [blame] | 8439 | #ifdef CONFIG_SMP |
Li Zefan | 4ce72a2 | 2008-10-22 15:25:26 +0800 | [diff] [blame] | 8440 | .select_task_rq = select_task_rq_fair, |
Paul Turner | 0a74bef | 2012-10-04 13:18:30 +0200 | [diff] [blame] | 8441 | .migrate_task_rq = migrate_task_rq_fair, |
Alex Shi | 141965c | 2013-06-26 13:05:39 +0800 | [diff] [blame] | 8442 | |
Christian Ehrhardt | 0bcdcf2 | 2009-11-30 12:16:46 +0100 | [diff] [blame] | 8443 | .rq_online = rq_online_fair, |
| 8444 | .rq_offline = rq_offline_fair, |
Peter Zijlstra | 88ec22d | 2009-12-16 18:04:41 +0100 | [diff] [blame] | 8445 | |
| 8446 | .task_waking = task_waking_fair, |
Peter Williams | 681f3e6 | 2007-10-24 18:23:51 +0200 | [diff] [blame] | 8447 | #endif |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8448 | |
Srivatsa Vaddagiri | 83b699e | 2007-10-15 17:00:08 +0200 | [diff] [blame] | 8449 | .set_curr_task = set_curr_task_fair, |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8450 | .task_tick = task_tick_fair, |
Peter Zijlstra | cd29fe6 | 2009-11-27 17:32:46 +0100 | [diff] [blame] | 8451 | .task_fork = task_fork_fair, |
Steven Rostedt | cb46984 | 2008-01-25 21:08:22 +0100 | [diff] [blame] | 8452 | |
| 8453 | .prio_changed = prio_changed_fair, |
Peter Zijlstra | da7a735 | 2011-01-17 17:03:27 +0100 | [diff] [blame] | 8454 | .switched_from = switched_from_fair, |
Steven Rostedt | cb46984 | 2008-01-25 21:08:22 +0100 | [diff] [blame] | 8455 | .switched_to = switched_to_fair, |
Peter Zijlstra | 810b381 | 2008-02-29 15:21:01 -0500 | [diff] [blame] | 8456 | |
Peter Williams | 0d721ce | 2009-09-21 01:31:53 +0000 | [diff] [blame] | 8457 | .get_rr_interval = get_rr_interval_fair, |
| 8458 | |
Stanislaw Gruszka | 6e99891 | 2014-11-12 16:58:44 +0100 | [diff] [blame] | 8459 | .update_curr = update_curr_fair, |
| 8460 | |
Peter Zijlstra | 810b381 | 2008-02-29 15:21:01 -0500 | [diff] [blame] | 8461 | #ifdef CONFIG_FAIR_GROUP_SCHED |
Peter Zijlstra | b2b5ce0 | 2010-10-15 15:24:15 +0200 | [diff] [blame] | 8462 | .task_move_group = task_move_group_fair, |
Peter Zijlstra | 810b381 | 2008-02-29 15:21:01 -0500 | [diff] [blame] | 8463 | #endif |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8464 | }; |
| 8465 | |
| 8466 | #ifdef CONFIG_SCHED_DEBUG |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8467 | void print_cfs_stats(struct seq_file *m, int cpu) |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8468 | { |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8469 | struct cfs_rq *cfs_rq; |
| 8470 | |
Peter Zijlstra | 5973e5b | 2008-01-25 21:08:34 +0100 | [diff] [blame] | 8471 | rcu_read_lock(); |
Ingo Molnar | c3b64f1 | 2007-08-09 11:16:51 +0200 | [diff] [blame] | 8472 | for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq) |
Ingo Molnar | 5cef9ec | 2007-08-09 11:16:47 +0200 | [diff] [blame] | 8473 | print_cfs_rq(m, cpu, cfs_rq); |
Peter Zijlstra | 5973e5b | 2008-01-25 21:08:34 +0100 | [diff] [blame] | 8474 | rcu_read_unlock(); |
Ingo Molnar | bf0f6f2 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 8475 | } |
Srikar Dronamraju | 397f237 | 2015-06-25 22:51:43 +0530 | [diff] [blame] | 8476 | |
| 8477 | #ifdef CONFIG_NUMA_BALANCING |
| 8478 | void show_numa_stats(struct task_struct *p, struct seq_file *m) |
| 8479 | { |
| 8480 | int node; |
| 8481 | unsigned long tsf = 0, tpf = 0, gsf = 0, gpf = 0; |
| 8482 | |
| 8483 | for_each_online_node(node) { |
| 8484 | if (p->numa_faults) { |
| 8485 | tsf = p->numa_faults[task_faults_idx(NUMA_MEM, node, 0)]; |
| 8486 | tpf = p->numa_faults[task_faults_idx(NUMA_MEM, node, 1)]; |
| 8487 | } |
| 8488 | if (p->numa_group) { |
| 8489 | gsf = p->numa_group->faults[task_faults_idx(NUMA_MEM, node, 0)], |
| 8490 | gpf = p->numa_group->faults[task_faults_idx(NUMA_MEM, node, 1)]; |
| 8491 | } |
| 8492 | print_numa_stats(m, node, tsf, tpf, gsf, gpf); |
| 8493 | } |
| 8494 | } |
| 8495 | #endif /* CONFIG_NUMA_BALANCING */ |
| 8496 | #endif /* CONFIG_SCHED_DEBUG */ |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8497 | |
| 8498 | __init void init_sched_fair_class(void) |
| 8499 | { |
| 8500 | #ifdef CONFIG_SMP |
| 8501 | open_softirq(SCHED_SOFTIRQ, run_rebalance_domains); |
| 8502 | |
Frederic Weisbecker | 3451d02 | 2011-08-10 23:21:01 +0200 | [diff] [blame] | 8503 | #ifdef CONFIG_NO_HZ_COMMON |
Diwakar Tundlam | 554ceca | 2012-03-07 14:44:26 -0800 | [diff] [blame] | 8504 | nohz.next_balance = jiffies; |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8505 | zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT); |
Suresh Siddha | 7132596 | 2012-01-19 18:28:57 -0800 | [diff] [blame] | 8506 | cpu_notifier(sched_ilb_notifier, 0); |
Peter Zijlstra | 029632f | 2011-10-25 10:00:11 +0200 | [diff] [blame] | 8507 | #endif |
| 8508 | #endif /* SMP */ |
| 8509 | |
| 8510 | } |