| /* |
| * Read-Copy Update mechanism for mutual exclusion (tree-based version) |
| * Internal non-public definitions. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, you can access it online at |
| * http://www.gnu.org/licenses/gpl-2.0.html. |
| * |
| * Copyright IBM Corporation, 2008 |
| * |
| * Author: Ingo Molnar <mingo@elte.hu> |
| * Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
| */ |
| |
| #include <linux/cache.h> |
| #include <linux/spinlock.h> |
| #include <linux/threads.h> |
| #include <linux/cpumask.h> |
| #include <linux/seqlock.h> |
| #include <linux/stop_machine.h> |
| |
| /* |
| * Define shape of hierarchy based on NR_CPUS, CONFIG_RCU_FANOUT, and |
| * CONFIG_RCU_FANOUT_LEAF. |
| * In theory, it should be possible to add more levels straightforwardly. |
| * In practice, this did work well going from three levels to four. |
| * Of course, your mileage may vary. |
| */ |
| |
| #ifdef CONFIG_RCU_FANOUT |
| #define RCU_FANOUT CONFIG_RCU_FANOUT |
| #else /* #ifdef CONFIG_RCU_FANOUT */ |
| # ifdef CONFIG_64BIT |
| # define RCU_FANOUT 64 |
| # else |
| # define RCU_FANOUT 32 |
| # endif |
| #endif /* #else #ifdef CONFIG_RCU_FANOUT */ |
| |
| #ifdef CONFIG_RCU_FANOUT_LEAF |
| #define RCU_FANOUT_LEAF CONFIG_RCU_FANOUT_LEAF |
| #else /* #ifdef CONFIG_RCU_FANOUT_LEAF */ |
| # ifdef CONFIG_64BIT |
| # define RCU_FANOUT_LEAF 64 |
| # else |
| # define RCU_FANOUT_LEAF 32 |
| # endif |
| #endif /* #else #ifdef CONFIG_RCU_FANOUT_LEAF */ |
| |
| #define RCU_FANOUT_1 (RCU_FANOUT_LEAF) |
| #define RCU_FANOUT_2 (RCU_FANOUT_1 * RCU_FANOUT) |
| #define RCU_FANOUT_3 (RCU_FANOUT_2 * RCU_FANOUT) |
| #define RCU_FANOUT_4 (RCU_FANOUT_3 * RCU_FANOUT) |
| |
| #if NR_CPUS <= RCU_FANOUT_1 |
| # define RCU_NUM_LVLS 1 |
| # define NUM_RCU_LVL_0 1 |
| # define NUM_RCU_NODES NUM_RCU_LVL_0 |
| # define NUM_RCU_LVL_INIT { NUM_RCU_LVL_0 } |
| # define RCU_NODE_NAME_INIT { "rcu_node_0" } |
| # define RCU_FQS_NAME_INIT { "rcu_node_fqs_0" } |
| # define RCU_EXP_NAME_INIT { "rcu_node_exp_0" } |
| #elif NR_CPUS <= RCU_FANOUT_2 |
| # define RCU_NUM_LVLS 2 |
| # define NUM_RCU_LVL_0 1 |
| # define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1) |
| # define NUM_RCU_NODES (NUM_RCU_LVL_0 + NUM_RCU_LVL_1) |
| # define NUM_RCU_LVL_INIT { NUM_RCU_LVL_0, NUM_RCU_LVL_1 } |
| # define RCU_NODE_NAME_INIT { "rcu_node_0", "rcu_node_1" } |
| # define RCU_FQS_NAME_INIT { "rcu_node_fqs_0", "rcu_node_fqs_1" } |
| # define RCU_EXP_NAME_INIT { "rcu_node_exp_0", "rcu_node_exp_1" } |
| #elif NR_CPUS <= RCU_FANOUT_3 |
| # define RCU_NUM_LVLS 3 |
| # define NUM_RCU_LVL_0 1 |
| # define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2) |
| # define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1) |
| # define NUM_RCU_NODES (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2) |
| # define NUM_RCU_LVL_INIT { NUM_RCU_LVL_0, NUM_RCU_LVL_1, NUM_RCU_LVL_2 } |
| # define RCU_NODE_NAME_INIT { "rcu_node_0", "rcu_node_1", "rcu_node_2" } |
| # define RCU_FQS_NAME_INIT { "rcu_node_fqs_0", "rcu_node_fqs_1", "rcu_node_fqs_2" } |
| # define RCU_EXP_NAME_INIT { "rcu_node_exp_0", "rcu_node_exp_1", "rcu_node_exp_2" } |
| #elif NR_CPUS <= RCU_FANOUT_4 |
| # define RCU_NUM_LVLS 4 |
| # define NUM_RCU_LVL_0 1 |
| # define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_3) |
| # define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2) |
| # define NUM_RCU_LVL_3 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1) |
| # define NUM_RCU_NODES (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3) |
| # define NUM_RCU_LVL_INIT { NUM_RCU_LVL_0, NUM_RCU_LVL_1, NUM_RCU_LVL_2, NUM_RCU_LVL_3 } |
| # define RCU_NODE_NAME_INIT { "rcu_node_0", "rcu_node_1", "rcu_node_2", "rcu_node_3" } |
| # define RCU_FQS_NAME_INIT { "rcu_node_fqs_0", "rcu_node_fqs_1", "rcu_node_fqs_2", "rcu_node_fqs_3" } |
| # define RCU_EXP_NAME_INIT { "rcu_node_exp_0", "rcu_node_exp_1", "rcu_node_exp_2", "rcu_node_exp_3" } |
| #else |
| # error "CONFIG_RCU_FANOUT insufficient for NR_CPUS" |
| #endif /* #if (NR_CPUS) <= RCU_FANOUT_1 */ |
| |
| extern int rcu_num_lvls; |
| extern int rcu_num_nodes; |
| |
| /* |
| * Dynticks per-CPU state. |
| */ |
| struct rcu_dynticks { |
| long long dynticks_nesting; /* Track irq/process nesting level. */ |
| /* Process level is worth LLONG_MAX/2. */ |
| int dynticks_nmi_nesting; /* Track NMI nesting level. */ |
| atomic_t dynticks; /* Even value for idle, else odd. */ |
| #ifdef CONFIG_NO_HZ_FULL_SYSIDLE |
| long long dynticks_idle_nesting; |
| /* irq/process nesting level from idle. */ |
| atomic_t dynticks_idle; /* Even value for idle, else odd. */ |
| /* "Idle" excludes userspace execution. */ |
| unsigned long dynticks_idle_jiffies; |
| /* End of last non-NMI non-idle period. */ |
| #endif /* #ifdef CONFIG_NO_HZ_FULL_SYSIDLE */ |
| #ifdef CONFIG_RCU_FAST_NO_HZ |
| bool all_lazy; /* Are all CPU's CBs lazy? */ |
| unsigned long nonlazy_posted; |
| /* # times non-lazy CBs posted to CPU. */ |
| unsigned long nonlazy_posted_snap; |
| /* idle-period nonlazy_posted snapshot. */ |
| unsigned long last_accelerate; |
| /* Last jiffy CBs were accelerated. */ |
| unsigned long last_advance_all; |
| /* Last jiffy CBs were all advanced. */ |
| int tick_nohz_enabled_snap; /* Previously seen value from sysfs. */ |
| #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */ |
| }; |
| |
| /* RCU's kthread states for tracing. */ |
| #define RCU_KTHREAD_STOPPED 0 |
| #define RCU_KTHREAD_RUNNING 1 |
| #define RCU_KTHREAD_WAITING 2 |
| #define RCU_KTHREAD_OFFCPU 3 |
| #define RCU_KTHREAD_YIELDING 4 |
| #define RCU_KTHREAD_MAX 4 |
| |
| /* |
| * Definition for node within the RCU grace-period-detection hierarchy. |
| */ |
| struct rcu_node { |
| raw_spinlock_t lock; /* Root rcu_node's lock protects some */ |
| /* rcu_state fields as well as following. */ |
| unsigned long gpnum; /* Current grace period for this node. */ |
| /* This will either be equal to or one */ |
| /* behind the root rcu_node's gpnum. */ |
| unsigned long completed; /* Last GP completed for this node. */ |
| /* This will either be equal to or one */ |
| /* behind the root rcu_node's gpnum. */ |
| unsigned long qsmask; /* CPUs or groups that need to switch in */ |
| /* order for current grace period to proceed.*/ |
| /* In leaf rcu_node, each bit corresponds to */ |
| /* an rcu_data structure, otherwise, each */ |
| /* bit corresponds to a child rcu_node */ |
| /* structure. */ |
| unsigned long expmask; /* Groups that have ->blkd_tasks */ |
| /* elements that need to drain to allow the */ |
| /* current expedited grace period to */ |
| /* complete (only for PREEMPT_RCU). */ |
| unsigned long qsmaskinit; |
| /* Per-GP initial value for qsmask & expmask. */ |
| /* Initialized from ->qsmaskinitnext at the */ |
| /* beginning of each grace period. */ |
| unsigned long qsmaskinitnext; |
| /* Online CPUs for next grace period. */ |
| unsigned long grpmask; /* Mask to apply to parent qsmask. */ |
| /* Only one bit will be set in this mask. */ |
| int grplo; /* lowest-numbered CPU or group here. */ |
| int grphi; /* highest-numbered CPU or group here. */ |
| u8 grpnum; /* CPU/group number for next level up. */ |
| u8 level; /* root is at level 0. */ |
| bool wait_blkd_tasks;/* Necessary to wait for blocked tasks to */ |
| /* exit RCU read-side critical sections */ |
| /* before propagating offline up the */ |
| /* rcu_node tree? */ |
| struct rcu_node *parent; |
| struct list_head blkd_tasks; |
| /* Tasks blocked in RCU read-side critical */ |
| /* section. Tasks are placed at the head */ |
| /* of this list and age towards the tail. */ |
| struct list_head *gp_tasks; |
| /* Pointer to the first task blocking the */ |
| /* current grace period, or NULL if there */ |
| /* is no such task. */ |
| struct list_head *exp_tasks; |
| /* Pointer to the first task blocking the */ |
| /* current expedited grace period, or NULL */ |
| /* if there is no such task. If there */ |
| /* is no current expedited grace period, */ |
| /* then there can cannot be any such task. */ |
| struct list_head *boost_tasks; |
| /* Pointer to first task that needs to be */ |
| /* priority boosted, or NULL if no priority */ |
| /* boosting is needed for this rcu_node */ |
| /* structure. If there are no tasks */ |
| /* queued on this rcu_node structure that */ |
| /* are blocking the current grace period, */ |
| /* there can be no such task. */ |
| struct rt_mutex boost_mtx; |
| /* Used only for the priority-boosting */ |
| /* side effect, not as a lock. */ |
| unsigned long boost_time; |
| /* When to start boosting (jiffies). */ |
| struct task_struct *boost_kthread_task; |
| /* kthread that takes care of priority */ |
| /* boosting for this rcu_node structure. */ |
| unsigned int boost_kthread_status; |
| /* State of boost_kthread_task for tracing. */ |
| unsigned long n_tasks_boosted; |
| /* Total number of tasks boosted. */ |
| unsigned long n_exp_boosts; |
| /* Number of tasks boosted for expedited GP. */ |
| unsigned long n_normal_boosts; |
| /* Number of tasks boosted for normal GP. */ |
| unsigned long n_balk_blkd_tasks; |
| /* Refused to boost: no blocked tasks. */ |
| unsigned long n_balk_exp_gp_tasks; |
| /* Refused to boost: nothing blocking GP. */ |
| unsigned long n_balk_boost_tasks; |
| /* Refused to boost: already boosting. */ |
| unsigned long n_balk_notblocked; |
| /* Refused to boost: RCU RS CS still running. */ |
| unsigned long n_balk_notyet; |
| /* Refused to boost: not yet time. */ |
| unsigned long n_balk_nos; |
| /* Refused to boost: not sure why, though. */ |
| /* This can happen due to race conditions. */ |
| #ifdef CONFIG_RCU_NOCB_CPU |
| wait_queue_head_t nocb_gp_wq[2]; |
| /* Place for rcu_nocb_kthread() to wait GP. */ |
| #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ |
| int need_future_gp[2]; |
| /* Counts of upcoming no-CB GP requests. */ |
| raw_spinlock_t fqslock ____cacheline_internodealigned_in_smp; |
| |
| struct mutex exp_funnel_mutex ____cacheline_internodealigned_in_smp; |
| } ____cacheline_internodealigned_in_smp; |
| |
| /* |
| * Do a full breadth-first scan of the rcu_node structures for the |
| * specified rcu_state structure. |
| */ |
| #define rcu_for_each_node_breadth_first(rsp, rnp) \ |
| for ((rnp) = &(rsp)->node[0]; \ |
| (rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++) |
| |
| /* |
| * Do a breadth-first scan of the non-leaf rcu_node structures for the |
| * specified rcu_state structure. Note that if there is a singleton |
| * rcu_node tree with but one rcu_node structure, this loop is a no-op. |
| */ |
| #define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \ |
| for ((rnp) = &(rsp)->node[0]; \ |
| (rnp) < (rsp)->level[rcu_num_lvls - 1]; (rnp)++) |
| |
| /* |
| * Scan the leaves of the rcu_node hierarchy for the specified rcu_state |
| * structure. Note that if there is a singleton rcu_node tree with but |
| * one rcu_node structure, this loop -will- visit the rcu_node structure. |
| * It is still a leaf node, even if it is also the root node. |
| */ |
| #define rcu_for_each_leaf_node(rsp, rnp) \ |
| for ((rnp) = (rsp)->level[rcu_num_lvls - 1]; \ |
| (rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++) |
| |
| /* Index values for nxttail array in struct rcu_data. */ |
| #define RCU_DONE_TAIL 0 /* Also RCU_WAIT head. */ |
| #define RCU_WAIT_TAIL 1 /* Also RCU_NEXT_READY head. */ |
| #define RCU_NEXT_READY_TAIL 2 /* Also RCU_NEXT head. */ |
| #define RCU_NEXT_TAIL 3 |
| #define RCU_NEXT_SIZE 4 |
| |
| /* Per-CPU data for read-copy update. */ |
| struct rcu_data { |
| /* 1) quiescent-state and grace-period handling : */ |
| unsigned long completed; /* Track rsp->completed gp number */ |
| /* in order to detect GP end. */ |
| unsigned long gpnum; /* Highest gp number that this CPU */ |
| /* is aware of having started. */ |
| unsigned long rcu_qs_ctr_snap;/* Snapshot of rcu_qs_ctr to check */ |
| /* for rcu_all_qs() invocations. */ |
| bool passed_quiesce; /* User-mode/idle loop etc. */ |
| bool qs_pending; /* Core waits for quiesc state. */ |
| bool beenonline; /* CPU online at least once. */ |
| bool gpwrap; /* Possible gpnum/completed wrap. */ |
| struct rcu_node *mynode; /* This CPU's leaf of hierarchy */ |
| unsigned long grpmask; /* Mask to apply to leaf qsmask. */ |
| unsigned long ticks_this_gp; /* The number of scheduling-clock */ |
| /* ticks this CPU has handled */ |
| /* during and after the last grace */ |
| /* period it is aware of. */ |
| struct cpu_stop_work exp_stop_work; |
| /* Expedited grace-period control */ |
| /* for CPU stopping. */ |
| |
| /* 2) batch handling */ |
| /* |
| * If nxtlist is not NULL, it is partitioned as follows. |
| * Any of the partitions might be empty, in which case the |
| * pointer to that partition will be equal to the pointer for |
| * the following partition. When the list is empty, all of |
| * the nxttail elements point to the ->nxtlist pointer itself, |
| * which in that case is NULL. |
| * |
| * [nxtlist, *nxttail[RCU_DONE_TAIL]): |
| * Entries that batch # <= ->completed |
| * The grace period for these entries has completed, and |
| * the other grace-period-completed entries may be moved |
| * here temporarily in rcu_process_callbacks(). |
| * [*nxttail[RCU_DONE_TAIL], *nxttail[RCU_WAIT_TAIL]): |
| * Entries that batch # <= ->completed - 1: waiting for current GP |
| * [*nxttail[RCU_WAIT_TAIL], *nxttail[RCU_NEXT_READY_TAIL]): |
| * Entries known to have arrived before current GP ended |
| * [*nxttail[RCU_NEXT_READY_TAIL], *nxttail[RCU_NEXT_TAIL]): |
| * Entries that might have arrived after current GP ended |
| * Note that the value of *nxttail[RCU_NEXT_TAIL] will |
| * always be NULL, as this is the end of the list. |
| */ |
| struct rcu_head *nxtlist; |
| struct rcu_head **nxttail[RCU_NEXT_SIZE]; |
| unsigned long nxtcompleted[RCU_NEXT_SIZE]; |
| /* grace periods for sublists. */ |
| long qlen_lazy; /* # of lazy queued callbacks */ |
| long qlen; /* # of queued callbacks, incl lazy */ |
| long qlen_last_fqs_check; |
| /* qlen at last check for QS forcing */ |
| unsigned long n_cbs_invoked; /* count of RCU cbs invoked. */ |
| unsigned long n_nocbs_invoked; /* count of no-CBs RCU cbs invoked. */ |
| unsigned long n_cbs_orphaned; /* RCU cbs orphaned by dying CPU */ |
| unsigned long n_cbs_adopted; /* RCU cbs adopted from dying CPU */ |
| unsigned long n_force_qs_snap; |
| /* did other CPU force QS recently? */ |
| long blimit; /* Upper limit on a processed batch */ |
| |
| /* 3) dynticks interface. */ |
| struct rcu_dynticks *dynticks; /* Shared per-CPU dynticks state. */ |
| int dynticks_snap; /* Per-GP tracking for dynticks. */ |
| |
| /* 4) reasons this CPU needed to be kicked by force_quiescent_state */ |
| unsigned long dynticks_fqs; /* Kicked due to dynticks idle. */ |
| unsigned long offline_fqs; /* Kicked due to being offline. */ |
| unsigned long cond_resched_completed; |
| /* Grace period that needs help */ |
| /* from cond_resched(). */ |
| |
| /* 5) __rcu_pending() statistics. */ |
| unsigned long n_rcu_pending; /* rcu_pending() calls since boot. */ |
| unsigned long n_rp_qs_pending; |
| unsigned long n_rp_report_qs; |
| unsigned long n_rp_cb_ready; |
| unsigned long n_rp_cpu_needs_gp; |
| unsigned long n_rp_gp_completed; |
| unsigned long n_rp_gp_started; |
| unsigned long n_rp_nocb_defer_wakeup; |
| unsigned long n_rp_need_nothing; |
| |
| /* 6) _rcu_barrier(), OOM callbacks, and expediting. */ |
| struct rcu_head barrier_head; |
| #ifdef CONFIG_RCU_FAST_NO_HZ |
| struct rcu_head oom_head; |
| #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */ |
| struct mutex exp_funnel_mutex; |
| bool exp_done; /* Expedited QS for this CPU? */ |
| |
| /* 7) Callback offloading. */ |
| #ifdef CONFIG_RCU_NOCB_CPU |
| struct rcu_head *nocb_head; /* CBs waiting for kthread. */ |
| struct rcu_head **nocb_tail; |
| atomic_long_t nocb_q_count; /* # CBs waiting for nocb */ |
| atomic_long_t nocb_q_count_lazy; /* invocation (all stages). */ |
| struct rcu_head *nocb_follower_head; /* CBs ready to invoke. */ |
| struct rcu_head **nocb_follower_tail; |
| wait_queue_head_t nocb_wq; /* For nocb kthreads to sleep on. */ |
| struct task_struct *nocb_kthread; |
| int nocb_defer_wakeup; /* Defer wakeup of nocb_kthread. */ |
| |
| /* The following fields are used by the leader, hence own cacheline. */ |
| struct rcu_head *nocb_gp_head ____cacheline_internodealigned_in_smp; |
| /* CBs waiting for GP. */ |
| struct rcu_head **nocb_gp_tail; |
| bool nocb_leader_sleep; /* Is the nocb leader thread asleep? */ |
| struct rcu_data *nocb_next_follower; |
| /* Next follower in wakeup chain. */ |
| |
| /* The following fields are used by the follower, hence new cachline. */ |
| struct rcu_data *nocb_leader ____cacheline_internodealigned_in_smp; |
| /* Leader CPU takes GP-end wakeups. */ |
| #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ |
| |
| /* 8) RCU CPU stall data. */ |
| unsigned int softirq_snap; /* Snapshot of softirq activity. */ |
| |
| int cpu; |
| struct rcu_state *rsp; |
| }; |
| |
| /* Values for fqs_state field in struct rcu_state. */ |
| #define RCU_GP_IDLE 0 /* No grace period in progress. */ |
| #define RCU_GP_INIT 1 /* Grace period being initialized. */ |
| #define RCU_SAVE_DYNTICK 2 /* Need to scan dyntick state. */ |
| #define RCU_FORCE_QS 3 /* Need to force quiescent state. */ |
| #define RCU_SIGNAL_INIT RCU_SAVE_DYNTICK |
| |
| /* Values for nocb_defer_wakeup field in struct rcu_data. */ |
| #define RCU_NOGP_WAKE_NOT 0 |
| #define RCU_NOGP_WAKE 1 |
| #define RCU_NOGP_WAKE_FORCE 2 |
| |
| #define RCU_JIFFIES_TILL_FORCE_QS (1 + (HZ > 250) + (HZ > 500)) |
| /* For jiffies_till_first_fqs and */ |
| /* and jiffies_till_next_fqs. */ |
| |
| #define RCU_JIFFIES_FQS_DIV 256 /* Very large systems need more */ |
| /* delay between bouts of */ |
| /* quiescent-state forcing. */ |
| |
| #define RCU_STALL_RAT_DELAY 2 /* Allow other CPUs time to take */ |
| /* at least one scheduling clock */ |
| /* irq before ratting on them. */ |
| |
| #define rcu_wait(cond) \ |
| do { \ |
| for (;;) { \ |
| set_current_state(TASK_INTERRUPTIBLE); \ |
| if (cond) \ |
| break; \ |
| schedule(); \ |
| } \ |
| __set_current_state(TASK_RUNNING); \ |
| } while (0) |
| |
| /* |
| * RCU global state, including node hierarchy. This hierarchy is |
| * represented in "heap" form in a dense array. The root (first level) |
| * of the hierarchy is in ->node[0] (referenced by ->level[0]), the second |
| * level in ->node[1] through ->node[m] (->node[1] referenced by ->level[1]), |
| * and the third level in ->node[m+1] and following (->node[m+1] referenced |
| * by ->level[2]). The number of levels is determined by the number of |
| * CPUs and by CONFIG_RCU_FANOUT. Small systems will have a "hierarchy" |
| * consisting of a single rcu_node. |
| */ |
| struct rcu_state { |
| struct rcu_node node[NUM_RCU_NODES]; /* Hierarchy. */ |
| struct rcu_node *level[RCU_NUM_LVLS + 1]; |
| /* Hierarchy levels (+1 to */ |
| /* shut bogus gcc warning) */ |
| u8 flavor_mask; /* bit in flavor mask. */ |
| struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */ |
| void (*call)(struct rcu_head *head, /* call_rcu() flavor. */ |
| void (*func)(struct rcu_head *head)); |
| |
| /* The following fields are guarded by the root rcu_node's lock. */ |
| |
| u8 fqs_state ____cacheline_internodealigned_in_smp; |
| /* Force QS state. */ |
| u8 boost; /* Subject to priority boost. */ |
| unsigned long gpnum; /* Current gp number. */ |
| unsigned long completed; /* # of last completed gp. */ |
| struct task_struct *gp_kthread; /* Task for grace periods. */ |
| wait_queue_head_t gp_wq; /* Where GP task waits. */ |
| short gp_flags; /* Commands for GP task. */ |
| short gp_state; /* GP kthread sleep state. */ |
| |
| /* End of fields guarded by root rcu_node's lock. */ |
| |
| raw_spinlock_t orphan_lock ____cacheline_internodealigned_in_smp; |
| /* Protect following fields. */ |
| struct rcu_head *orphan_nxtlist; /* Orphaned callbacks that */ |
| /* need a grace period. */ |
| struct rcu_head **orphan_nxttail; /* Tail of above. */ |
| struct rcu_head *orphan_donelist; /* Orphaned callbacks that */ |
| /* are ready to invoke. */ |
| struct rcu_head **orphan_donetail; /* Tail of above. */ |
| long qlen_lazy; /* Number of lazy callbacks. */ |
| long qlen; /* Total number of callbacks. */ |
| /* End of fields guarded by orphan_lock. */ |
| |
| struct mutex barrier_mutex; /* Guards barrier fields. */ |
| atomic_t barrier_cpu_count; /* # CPUs waiting on. */ |
| struct completion barrier_completion; /* Wake at barrier end. */ |
| unsigned long barrier_sequence; /* ++ at start and end of */ |
| /* _rcu_barrier(). */ |
| /* End of fields guarded by barrier_mutex. */ |
| |
| unsigned long expedited_sequence; /* Take a ticket. */ |
| atomic_long_t expedited_tryfail; /* # acquisition failures. */ |
| atomic_long_t expedited_workdone1; /* # done by others #1. */ |
| atomic_long_t expedited_workdone2; /* # done by others #2. */ |
| atomic_long_t expedited_workdone3; /* # done by others #3. */ |
| atomic_long_t expedited_normal; /* # fallbacks to normal. */ |
| atomic_t expedited_need_qs; /* # CPUs left to check in. */ |
| wait_queue_head_t expedited_wq; /* Wait for check-ins. */ |
| |
| unsigned long jiffies_force_qs; /* Time at which to invoke */ |
| /* force_quiescent_state(). */ |
| unsigned long n_force_qs; /* Number of calls to */ |
| /* force_quiescent_state(). */ |
| unsigned long n_force_qs_lh; /* ~Number of calls leaving */ |
| /* due to lock unavailable. */ |
| unsigned long n_force_qs_ngp; /* Number of calls leaving */ |
| /* due to no GP active. */ |
| unsigned long gp_start; /* Time at which GP started, */ |
| /* but in jiffies. */ |
| unsigned long gp_activity; /* Time of last GP kthread */ |
| /* activity in jiffies. */ |
| unsigned long jiffies_stall; /* Time at which to check */ |
| /* for CPU stalls. */ |
| unsigned long jiffies_resched; /* Time at which to resched */ |
| /* a reluctant CPU. */ |
| unsigned long n_force_qs_gpstart; /* Snapshot of n_force_qs at */ |
| /* GP start. */ |
| unsigned long gp_max; /* Maximum GP duration in */ |
| /* jiffies. */ |
| const char *name; /* Name of structure. */ |
| char abbr; /* Abbreviated name. */ |
| struct list_head flavors; /* List of RCU flavors. */ |
| }; |
| |
| /* Values for rcu_state structure's gp_flags field. */ |
| #define RCU_GP_FLAG_INIT 0x1 /* Need grace-period initialization. */ |
| #define RCU_GP_FLAG_FQS 0x2 /* Need grace-period quiescent-state forcing. */ |
| |
| /* Values for rcu_state structure's gp_flags field. */ |
| #define RCU_GP_WAIT_INIT 0 /* Initial state. */ |
| #define RCU_GP_WAIT_GPS 1 /* Wait for grace-period start. */ |
| #define RCU_GP_DONE_GPS 2 /* Wait done for grace-period start. */ |
| #define RCU_GP_WAIT_FQS 3 /* Wait for force-quiescent-state time. */ |
| #define RCU_GP_DONE_FQS 4 /* Wait done for force-quiescent-state time. */ |
| #define RCU_GP_CLEANUP 5 /* Grace-period cleanup started. */ |
| #define RCU_GP_CLEANED 6 /* Grace-period cleanup complete. */ |
| |
| extern struct list_head rcu_struct_flavors; |
| |
| /* Sequence through rcu_state structures for each RCU flavor. */ |
| #define for_each_rcu_flavor(rsp) \ |
| list_for_each_entry((rsp), &rcu_struct_flavors, flavors) |
| |
| /* |
| * RCU implementation internal declarations: |
| */ |
| extern struct rcu_state rcu_sched_state; |
| |
| extern struct rcu_state rcu_bh_state; |
| |
| #ifdef CONFIG_PREEMPT_RCU |
| extern struct rcu_state rcu_preempt_state; |
| #endif /* #ifdef CONFIG_PREEMPT_RCU */ |
| |
| #ifdef CONFIG_RCU_BOOST |
| DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status); |
| DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu); |
| DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops); |
| DECLARE_PER_CPU(char, rcu_cpu_has_work); |
| #endif /* #ifdef CONFIG_RCU_BOOST */ |
| |
| #ifndef RCU_TREE_NONCORE |
| |
| /* Forward declarations for rcutree_plugin.h */ |
| static void rcu_bootup_announce(void); |
| static void rcu_preempt_note_context_switch(void); |
| static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp); |
| #ifdef CONFIG_HOTPLUG_CPU |
| static bool rcu_preempt_has_tasks(struct rcu_node *rnp); |
| #endif /* #ifdef CONFIG_HOTPLUG_CPU */ |
| static void rcu_print_detail_task_stall(struct rcu_state *rsp); |
| static int rcu_print_task_stall(struct rcu_node *rnp); |
| static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); |
| static void rcu_preempt_check_callbacks(void); |
| void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); |
| static void __init __rcu_init_preempt(void); |
| static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags); |
| static void rcu_preempt_boost_start_gp(struct rcu_node *rnp); |
| static void invoke_rcu_callbacks_kthread(void); |
| static bool rcu_is_callbacks_kthread(void); |
| #ifdef CONFIG_RCU_BOOST |
| static void rcu_preempt_do_callbacks(void); |
| static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp, |
| struct rcu_node *rnp); |
| #endif /* #ifdef CONFIG_RCU_BOOST */ |
| static void __init rcu_spawn_boost_kthreads(void); |
| static void rcu_prepare_kthreads(int cpu); |
| static void rcu_cleanup_after_idle(void); |
| static void rcu_prepare_for_idle(void); |
| static void rcu_idle_count_callbacks_posted(void); |
| static bool rcu_preempt_has_tasks(struct rcu_node *rnp); |
| static void print_cpu_stall_info_begin(void); |
| static void print_cpu_stall_info(struct rcu_state *rsp, int cpu); |
| static void print_cpu_stall_info_end(void); |
| static void zero_cpu_stall_ticks(struct rcu_data *rdp); |
| static void increment_cpu_stall_ticks(void); |
| static bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu); |
| static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq); |
| static void rcu_nocb_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp); |
| static void rcu_init_one_nocb(struct rcu_node *rnp); |
| static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp, |
| bool lazy, unsigned long flags); |
| static bool rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp, |
| struct rcu_data *rdp, |
| unsigned long flags); |
| static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp); |
| static void do_nocb_deferred_wakeup(struct rcu_data *rdp); |
| static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp); |
| static void rcu_spawn_all_nocb_kthreads(int cpu); |
| static void __init rcu_spawn_nocb_kthreads(void); |
| #ifdef CONFIG_RCU_NOCB_CPU |
| static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp); |
| #endif /* #ifdef CONFIG_RCU_NOCB_CPU */ |
| static void __maybe_unused rcu_kick_nohz_cpu(int cpu); |
| static bool init_nocb_callback_list(struct rcu_data *rdp); |
| static void rcu_sysidle_enter(int irq); |
| static void rcu_sysidle_exit(int irq); |
| static void rcu_sysidle_check_cpu(struct rcu_data *rdp, bool *isidle, |
| unsigned long *maxj); |
| static bool is_sysidle_rcu_state(struct rcu_state *rsp); |
| static void rcu_sysidle_report_gp(struct rcu_state *rsp, int isidle, |
| unsigned long maxj); |
| static void rcu_bind_gp_kthread(void); |
| static void rcu_sysidle_init_percpu_data(struct rcu_dynticks *rdtp); |
| static bool rcu_nohz_full_cpu(struct rcu_state *rsp); |
| static void rcu_dynticks_task_enter(void); |
| static void rcu_dynticks_task_exit(void); |
| |
| #endif /* #ifndef RCU_TREE_NONCORE */ |
| |
| #ifdef CONFIG_RCU_TRACE |
| /* Read out queue lengths for tracing. */ |
| static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll) |
| { |
| #ifdef CONFIG_RCU_NOCB_CPU |
| *ql = atomic_long_read(&rdp->nocb_q_count); |
| *qll = atomic_long_read(&rdp->nocb_q_count_lazy); |
| #else /* #ifdef CONFIG_RCU_NOCB_CPU */ |
| *ql = 0; |
| *qll = 0; |
| #endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */ |
| } |
| #endif /* #ifdef CONFIG_RCU_TRACE */ |
