| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * CPUFreq governor based on scheduler-provided CPU utilization data. |
| * |
| * Copyright (C) 2016, Intel Corporation |
| * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include "sched.h" |
| |
| #include <linux/sched/cpufreq.h> |
| #include <trace/events/power.h> |
| |
| #define IOWAIT_BOOST_MIN (SCHED_CAPACITY_SCALE / 8) |
| |
| struct sugov_tunables { |
| struct gov_attr_set attr_set; |
| unsigned int rate_limit_us; |
| }; |
| |
| struct sugov_policy { |
| struct cpufreq_policy *policy; |
| |
| struct sugov_tunables *tunables; |
| struct list_head tunables_hook; |
| |
| raw_spinlock_t update_lock; /* For shared policies */ |
| u64 last_freq_update_time; |
| s64 freq_update_delay_ns; |
| unsigned int next_freq; |
| unsigned int cached_raw_freq; |
| |
| /* The next fields are only needed if fast switch cannot be used: */ |
| struct irq_work irq_work; |
| struct kthread_work work; |
| struct mutex work_lock; |
| struct kthread_worker worker; |
| struct task_struct *thread; |
| bool work_in_progress; |
| |
| bool limits_changed; |
| bool need_freq_update; |
| }; |
| |
| struct sugov_cpu { |
| struct update_util_data update_util; |
| struct sugov_policy *sg_policy; |
| unsigned int cpu; |
| |
| bool iowait_boost_pending; |
| unsigned int iowait_boost; |
| u64 last_update; |
| |
| unsigned long bw_dl; |
| unsigned long max; |
| |
| /* The field below is for single-CPU policies only: */ |
| #ifdef CONFIG_NO_HZ_COMMON |
| unsigned long saved_idle_calls; |
| #endif |
| }; |
| |
| static DEFINE_PER_CPU(struct sugov_cpu, sugov_cpu); |
| |
| /************************ Governor internals ***********************/ |
| |
| static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time) |
| { |
| s64 delta_ns; |
| |
| /* |
| * Since cpufreq_update_util() is called with rq->lock held for |
| * the @target_cpu, our per-CPU data is fully serialized. |
| * |
| * However, drivers cannot in general deal with cross-CPU |
| * requests, so while get_next_freq() will work, our |
| * sugov_update_commit() call may not for the fast switching platforms. |
| * |
| * Hence stop here for remote requests if they aren't supported |
| * by the hardware, as calculating the frequency is pointless if |
| * we cannot in fact act on it. |
| * |
| * This is needed on the slow switching platforms too to prevent CPUs |
| * going offline from leaving stale IRQ work items behind. |
| */ |
| if (!cpufreq_this_cpu_can_update(sg_policy->policy)) |
| return false; |
| |
| if (unlikely(sg_policy->limits_changed)) { |
| sg_policy->limits_changed = false; |
| sg_policy->need_freq_update = true; |
| return true; |
| } |
| |
| delta_ns = time - sg_policy->last_freq_update_time; |
| |
| return delta_ns >= sg_policy->freq_update_delay_ns; |
| } |
| |
| static bool sugov_update_next_freq(struct sugov_policy *sg_policy, u64 time, |
| unsigned int next_freq) |
| { |
| if (sg_policy->next_freq == next_freq) |
| return false; |
| |
| sg_policy->next_freq = next_freq; |
| sg_policy->last_freq_update_time = time; |
| |
| return true; |
| } |
| |
| static void sugov_fast_switch(struct sugov_policy *sg_policy, u64 time, |
| unsigned int next_freq) |
| { |
| struct cpufreq_policy *policy = sg_policy->policy; |
| int cpu; |
| |
| if (!sugov_update_next_freq(sg_policy, time, next_freq)) |
| return; |
| |
| next_freq = cpufreq_driver_fast_switch(policy, next_freq); |
| if (!next_freq) |
| return; |
| |
| policy->cur = next_freq; |
| |
| if (trace_cpu_frequency_enabled()) { |
| for_each_cpu(cpu, policy->cpus) |
| trace_cpu_frequency(next_freq, cpu); |
| } |
| } |
| |
| static void sugov_deferred_update(struct sugov_policy *sg_policy, u64 time, |
| unsigned int next_freq) |
| { |
| if (!sugov_update_next_freq(sg_policy, time, next_freq)) |
| return; |
| |
| if (!sg_policy->work_in_progress) { |
| sg_policy->work_in_progress = true; |
| irq_work_queue(&sg_policy->irq_work); |
| } |
| } |
| |
| /** |
| * get_next_freq - Compute a new frequency for a given cpufreq policy. |
| * @sg_policy: schedutil policy object to compute the new frequency for. |
| * @util: Current CPU utilization. |
| * @max: CPU capacity. |
| * |
| * If the utilization is frequency-invariant, choose the new frequency to be |
| * proportional to it, that is |
| * |
| * next_freq = C * max_freq * util / max |
| * |
| * Otherwise, approximate the would-be frequency-invariant utilization by |
| * util_raw * (curr_freq / max_freq) which leads to |
| * |
| * next_freq = C * curr_freq * util_raw / max |
| * |
| * Take C = 1.25 for the frequency tipping point at (util / max) = 0.8. |
| * |
| * The lowest driver-supported frequency which is equal or greater than the raw |
| * next_freq (as calculated above) is returned, subject to policy min/max and |
| * cpufreq driver limitations. |
| */ |
| static unsigned int get_next_freq(struct sugov_policy *sg_policy, |
| unsigned long util, unsigned long max) |
| { |
| struct cpufreq_policy *policy = sg_policy->policy; |
| unsigned int freq = arch_scale_freq_invariant() ? |
| policy->cpuinfo.max_freq : policy->cur; |
| |
| freq = map_util_freq(util, freq, max); |
| |
| if (freq == sg_policy->cached_raw_freq && !sg_policy->need_freq_update) |
| return sg_policy->next_freq; |
| |
| sg_policy->need_freq_update = false; |
| sg_policy->cached_raw_freq = freq; |
| return cpufreq_driver_resolve_freq(policy, freq); |
| } |
| |
| /* |
| * This function computes an effective utilization for the given CPU, to be |
| * used for frequency selection given the linear relation: f = u * f_max. |
| * |
| * The scheduler tracks the following metrics: |
| * |
| * cpu_util_{cfs,rt,dl,irq}() |
| * cpu_bw_dl() |
| * |
| * Where the cfs,rt and dl util numbers are tracked with the same metric and |
| * synchronized windows and are thus directly comparable. |
| * |
| * The cfs,rt,dl utilization are the running times measured with rq->clock_task |
| * which excludes things like IRQ and steal-time. These latter are then accrued |
| * in the irq utilization. |
| * |
| * The DL bandwidth number otoh is not a measured metric but a value computed |
| * based on the task model parameters and gives the minimal utilization |
| * required to meet deadlines. |
| */ |
| unsigned long schedutil_cpu_util(int cpu, unsigned long util_cfs, |
| unsigned long max, enum schedutil_type type, |
| struct task_struct *p) |
| { |
| unsigned long dl_util, util, irq; |
| struct rq *rq = cpu_rq(cpu); |
| |
| if (!IS_BUILTIN(CONFIG_UCLAMP_TASK) && |
| type == FREQUENCY_UTIL && rt_rq_is_runnable(&rq->rt)) { |
| return max; |
| } |
| |
| /* |
| * Early check to see if IRQ/steal time saturates the CPU, can be |
| * because of inaccuracies in how we track these -- see |
| * update_irq_load_avg(). |
| */ |
| irq = cpu_util_irq(rq); |
| if (unlikely(irq >= max)) |
| return max; |
| |
| /* |
| * Because the time spend on RT/DL tasks is visible as 'lost' time to |
| * CFS tasks and we use the same metric to track the effective |
| * utilization (PELT windows are synchronized) we can directly add them |
| * to obtain the CPU's actual utilization. |
| * |
| * CFS and RT utilization can be boosted or capped, depending on |
| * utilization clamp constraints requested by currently RUNNABLE |
| * tasks. |
| * When there are no CFS RUNNABLE tasks, clamps are released and |
| * frequency will be gracefully reduced with the utilization decay. |
| */ |
| util = util_cfs + cpu_util_rt(rq); |
| if (type == FREQUENCY_UTIL) |
| util = uclamp_util_with(rq, util, p); |
| |
| dl_util = cpu_util_dl(rq); |
| |
| /* |
| * For frequency selection we do not make cpu_util_dl() a permanent part |
| * of this sum because we want to use cpu_bw_dl() later on, but we need |
| * to check if the CFS+RT+DL sum is saturated (ie. no idle time) such |
| * that we select f_max when there is no idle time. |
| * |
| * NOTE: numerical errors or stop class might cause us to not quite hit |
| * saturation when we should -- something for later. |
| */ |
| if (util + dl_util >= max) |
| return max; |
| |
| /* |
| * OTOH, for energy computation we need the estimated running time, so |
| * include util_dl and ignore dl_bw. |
| */ |
| if (type == ENERGY_UTIL) |
| util += dl_util; |
| |
| /* |
| * There is still idle time; further improve the number by using the |
| * irq metric. Because IRQ/steal time is hidden from the task clock we |
| * need to scale the task numbers: |
| * |
| * max - irq |
| * U' = irq + --------- * U |
| * max |
| */ |
| util = scale_irq_capacity(util, irq, max); |
| util += irq; |
| |
| /* |
| * Bandwidth required by DEADLINE must always be granted while, for |
| * FAIR and RT, we use blocked utilization of IDLE CPUs as a mechanism |
| * to gracefully reduce the frequency when no tasks show up for longer |
| * periods of time. |
| * |
| * Ideally we would like to set bw_dl as min/guaranteed freq and util + |
| * bw_dl as requested freq. However, cpufreq is not yet ready for such |
| * an interface. So, we only do the latter for now. |
| */ |
| if (type == FREQUENCY_UTIL) |
| util += cpu_bw_dl(rq); |
| |
| return min(max, util); |
| } |
| |
| static unsigned long sugov_get_util(struct sugov_cpu *sg_cpu) |
| { |
| struct rq *rq = cpu_rq(sg_cpu->cpu); |
| unsigned long util = cpu_util_cfs(rq); |
| unsigned long max = arch_scale_cpu_capacity(sg_cpu->cpu); |
| |
| sg_cpu->max = max; |
| sg_cpu->bw_dl = cpu_bw_dl(rq); |
| |
| return schedutil_cpu_util(sg_cpu->cpu, util, max, FREQUENCY_UTIL, NULL); |
| } |
| |
| /** |
| * sugov_iowait_reset() - Reset the IO boost status of a CPU. |
| * @sg_cpu: the sugov data for the CPU to boost |
| * @time: the update time from the caller |
| * @set_iowait_boost: true if an IO boost has been requested |
| * |
| * The IO wait boost of a task is disabled after a tick since the last update |
| * of a CPU. If a new IO wait boost is requested after more then a tick, then |
| * we enable the boost starting from IOWAIT_BOOST_MIN, which improves energy |
| * efficiency by ignoring sporadic wakeups from IO. |
| */ |
| static bool sugov_iowait_reset(struct sugov_cpu *sg_cpu, u64 time, |
| bool set_iowait_boost) |
| { |
| s64 delta_ns = time - sg_cpu->last_update; |
| |
| /* Reset boost only if a tick has elapsed since last request */ |
| if (delta_ns <= TICK_NSEC) |
| return false; |
| |
| sg_cpu->iowait_boost = set_iowait_boost ? IOWAIT_BOOST_MIN : 0; |
| sg_cpu->iowait_boost_pending = set_iowait_boost; |
| |
| return true; |
| } |
| |
| /** |
| * sugov_iowait_boost() - Updates the IO boost status of a CPU. |
| * @sg_cpu: the sugov data for the CPU to boost |
| * @time: the update time from the caller |
| * @flags: SCHED_CPUFREQ_IOWAIT if the task is waking up after an IO wait |
| * |
| * Each time a task wakes up after an IO operation, the CPU utilization can be |
| * boosted to a certain utilization which doubles at each "frequent and |
| * successive" wakeup from IO, ranging from IOWAIT_BOOST_MIN to the utilization |
| * of the maximum OPP. |
| * |
| * To keep doubling, an IO boost has to be requested at least once per tick, |
| * otherwise we restart from the utilization of the minimum OPP. |
| */ |
| static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, u64 time, |
| unsigned int flags) |
| { |
| bool set_iowait_boost = flags & SCHED_CPUFREQ_IOWAIT; |
| |
| /* Reset boost if the CPU appears to have been idle enough */ |
| if (sg_cpu->iowait_boost && |
| sugov_iowait_reset(sg_cpu, time, set_iowait_boost)) |
| return; |
| |
| /* Boost only tasks waking up after IO */ |
| if (!set_iowait_boost) |
| return; |
| |
| /* Ensure boost doubles only one time at each request */ |
| if (sg_cpu->iowait_boost_pending) |
| return; |
| sg_cpu->iowait_boost_pending = true; |
| |
| /* Double the boost at each request */ |
| if (sg_cpu->iowait_boost) { |
| sg_cpu->iowait_boost = |
| min_t(unsigned int, sg_cpu->iowait_boost << 1, SCHED_CAPACITY_SCALE); |
| return; |
| } |
| |
| /* First wakeup after IO: start with minimum boost */ |
| sg_cpu->iowait_boost = IOWAIT_BOOST_MIN; |
| } |
| |
| /** |
| * sugov_iowait_apply() - Apply the IO boost to a CPU. |
| * @sg_cpu: the sugov data for the cpu to boost |
| * @time: the update time from the caller |
| * @util: the utilization to (eventually) boost |
| * @max: the maximum value the utilization can be boosted to |
| * |
| * A CPU running a task which woken up after an IO operation can have its |
| * utilization boosted to speed up the completion of those IO operations. |
| * The IO boost value is increased each time a task wakes up from IO, in |
| * sugov_iowait_apply(), and it's instead decreased by this function, |
| * each time an increase has not been requested (!iowait_boost_pending). |
| * |
| * A CPU which also appears to have been idle for at least one tick has also |
| * its IO boost utilization reset. |
| * |
| * This mechanism is designed to boost high frequently IO waiting tasks, while |
| * being more conservative on tasks which does sporadic IO operations. |
| */ |
| static unsigned long sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time, |
| unsigned long util, unsigned long max) |
| { |
| unsigned long boost; |
| |
| /* No boost currently required */ |
| if (!sg_cpu->iowait_boost) |
| return util; |
| |
| /* Reset boost if the CPU appears to have been idle enough */ |
| if (sugov_iowait_reset(sg_cpu, time, false)) |
| return util; |
| |
| if (!sg_cpu->iowait_boost_pending) { |
| /* |
| * No boost pending; reduce the boost value. |
| */ |
| sg_cpu->iowait_boost >>= 1; |
| if (sg_cpu->iowait_boost < IOWAIT_BOOST_MIN) { |
| sg_cpu->iowait_boost = 0; |
| return util; |
| } |
| } |
| |
| sg_cpu->iowait_boost_pending = false; |
| |
| /* |
| * @util is already in capacity scale; convert iowait_boost |
| * into the same scale so we can compare. |
| */ |
| boost = (sg_cpu->iowait_boost * max) >> SCHED_CAPACITY_SHIFT; |
| return max(boost, util); |
| } |
| |
| #ifdef CONFIG_NO_HZ_COMMON |
| static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) |
| { |
| unsigned long idle_calls = tick_nohz_get_idle_calls_cpu(sg_cpu->cpu); |
| bool ret = idle_calls == sg_cpu->saved_idle_calls; |
| |
| sg_cpu->saved_idle_calls = idle_calls; |
| return ret; |
| } |
| #else |
| static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; } |
| #endif /* CONFIG_NO_HZ_COMMON */ |
| |
| /* |
| * Make sugov_should_update_freq() ignore the rate limit when DL |
| * has increased the utilization. |
| */ |
| static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu, struct sugov_policy *sg_policy) |
| { |
| if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_dl) |
| sg_policy->limits_changed = true; |
| } |
| |
| static void sugov_update_single(struct update_util_data *hook, u64 time, |
| unsigned int flags) |
| { |
| struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util); |
| struct sugov_policy *sg_policy = sg_cpu->sg_policy; |
| unsigned long util, max; |
| unsigned int next_f; |
| bool busy; |
| |
| sugov_iowait_boost(sg_cpu, time, flags); |
| sg_cpu->last_update = time; |
| |
| ignore_dl_rate_limit(sg_cpu, sg_policy); |
| |
| if (!sugov_should_update_freq(sg_policy, time)) |
| return; |
| |
| /* Limits may have changed, don't skip frequency update */ |
| busy = !sg_policy->need_freq_update && sugov_cpu_is_busy(sg_cpu); |
| |
| util = sugov_get_util(sg_cpu); |
| max = sg_cpu->max; |
| util = sugov_iowait_apply(sg_cpu, time, util, max); |
| next_f = get_next_freq(sg_policy, util, max); |
| /* |
| * Do not reduce the frequency if the CPU has not been idle |
| * recently, as the reduction is likely to be premature then. |
| */ |
| if (busy && next_f < sg_policy->next_freq) { |
| next_f = sg_policy->next_freq; |
| |
| /* Reset cached freq as next_freq has changed */ |
| sg_policy->cached_raw_freq = 0; |
| } |
| |
| /* |
| * This code runs under rq->lock for the target CPU, so it won't run |
| * concurrently on two different CPUs for the same target and it is not |
| * necessary to acquire the lock in the fast switch case. |
| */ |
| if (sg_policy->policy->fast_switch_enabled) { |
| sugov_fast_switch(sg_policy, time, next_f); |
| } else { |
| raw_spin_lock(&sg_policy->update_lock); |
| sugov_deferred_update(sg_policy, time, next_f); |
| raw_spin_unlock(&sg_policy->update_lock); |
| } |
| } |
| |
| static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time) |
| { |
| struct sugov_policy *sg_policy = sg_cpu->sg_policy; |
| struct cpufreq_policy *policy = sg_policy->policy; |
| unsigned long util = 0, max = 1; |
| unsigned int j; |
| |
| for_each_cpu(j, policy->cpus) { |
| struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j); |
| unsigned long j_util, j_max; |
| |
| j_util = sugov_get_util(j_sg_cpu); |
| j_max = j_sg_cpu->max; |
| j_util = sugov_iowait_apply(j_sg_cpu, time, j_util, j_max); |
| |
| if (j_util * max > j_max * util) { |
| util = j_util; |
| max = j_max; |
| } |
| } |
| |
| return get_next_freq(sg_policy, util, max); |
| } |
| |
| static void |
| sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int flags) |
| { |
| struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util); |
| struct sugov_policy *sg_policy = sg_cpu->sg_policy; |
| unsigned int next_f; |
| |
| raw_spin_lock(&sg_policy->update_lock); |
| |
| sugov_iowait_boost(sg_cpu, time, flags); |
| sg_cpu->last_update = time; |
| |
| ignore_dl_rate_limit(sg_cpu, sg_policy); |
| |
| if (sugov_should_update_freq(sg_policy, time)) { |
| next_f = sugov_next_freq_shared(sg_cpu, time); |
| |
| if (sg_policy->policy->fast_switch_enabled) |
| sugov_fast_switch(sg_policy, time, next_f); |
| else |
| sugov_deferred_update(sg_policy, time, next_f); |
| } |
| |
| raw_spin_unlock(&sg_policy->update_lock); |
| } |
| |
| static void sugov_work(struct kthread_work *work) |
| { |
| struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work); |
| unsigned int freq; |
| unsigned long flags; |
| |
| /* |
| * Hold sg_policy->update_lock shortly to handle the case where: |
| * incase sg_policy->next_freq is read here, and then updated by |
| * sugov_deferred_update() just before work_in_progress is set to false |
| * here, we may miss queueing the new update. |
| * |
| * Note: If a work was queued after the update_lock is released, |
| * sugov_work() will just be called again by kthread_work code; and the |
| * request will be proceed before the sugov thread sleeps. |
| */ |
| raw_spin_lock_irqsave(&sg_policy->update_lock, flags); |
| freq = sg_policy->next_freq; |
| sg_policy->work_in_progress = false; |
| raw_spin_unlock_irqrestore(&sg_policy->update_lock, flags); |
| |
| mutex_lock(&sg_policy->work_lock); |
| __cpufreq_driver_target(sg_policy->policy, freq, CPUFREQ_RELATION_L); |
| mutex_unlock(&sg_policy->work_lock); |
| } |
| |
| static void sugov_irq_work(struct irq_work *irq_work) |
| { |
| struct sugov_policy *sg_policy; |
| |
| sg_policy = container_of(irq_work, struct sugov_policy, irq_work); |
| |
| kthread_queue_work(&sg_policy->worker, &sg_policy->work); |
| } |
| |
| /************************** sysfs interface ************************/ |
| |
| static struct sugov_tunables *global_tunables; |
| static DEFINE_MUTEX(global_tunables_lock); |
| |
| static inline struct sugov_tunables *to_sugov_tunables(struct gov_attr_set *attr_set) |
| { |
| return container_of(attr_set, struct sugov_tunables, attr_set); |
| } |
| |
| static ssize_t rate_limit_us_show(struct gov_attr_set *attr_set, char *buf) |
| { |
| struct sugov_tunables *tunables = to_sugov_tunables(attr_set); |
| |
| return sprintf(buf, "%u\n", tunables->rate_limit_us); |
| } |
| |
| static ssize_t |
| rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf, size_t count) |
| { |
| struct sugov_tunables *tunables = to_sugov_tunables(attr_set); |
| struct sugov_policy *sg_policy; |
| unsigned int rate_limit_us; |
| |
| if (kstrtouint(buf, 10, &rate_limit_us)) |
| return -EINVAL; |
| |
| tunables->rate_limit_us = rate_limit_us; |
| |
| list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook) |
| sg_policy->freq_update_delay_ns = rate_limit_us * NSEC_PER_USEC; |
| |
| return count; |
| } |
| |
| static struct governor_attr rate_limit_us = __ATTR_RW(rate_limit_us); |
| |
| static struct attribute *sugov_attrs[] = { |
| &rate_limit_us.attr, |
| NULL |
| }; |
| ATTRIBUTE_GROUPS(sugov); |
| |
| static struct kobj_type sugov_tunables_ktype = { |
| .default_groups = sugov_groups, |
| .sysfs_ops = &governor_sysfs_ops, |
| }; |
| |
| /********************** cpufreq governor interface *********************/ |
| |
| struct cpufreq_governor schedutil_gov; |
| |
| static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy) |
| { |
| struct sugov_policy *sg_policy; |
| |
| sg_policy = kzalloc(sizeof(*sg_policy), GFP_KERNEL); |
| if (!sg_policy) |
| return NULL; |
| |
| sg_policy->policy = policy; |
| raw_spin_lock_init(&sg_policy->update_lock); |
| return sg_policy; |
| } |
| |
| static void sugov_policy_free(struct sugov_policy *sg_policy) |
| { |
| kfree(sg_policy); |
| } |
| |
| static int sugov_kthread_create(struct sugov_policy *sg_policy) |
| { |
| struct task_struct *thread; |
| struct sched_attr attr = { |
| .size = sizeof(struct sched_attr), |
| .sched_policy = SCHED_DEADLINE, |
| .sched_flags = SCHED_FLAG_SUGOV, |
| .sched_nice = 0, |
| .sched_priority = 0, |
| /* |
| * Fake (unused) bandwidth; workaround to "fix" |
| * priority inheritance. |
| */ |
| .sched_runtime = 1000000, |
| .sched_deadline = 10000000, |
| .sched_period = 10000000, |
| }; |
| struct cpufreq_policy *policy = sg_policy->policy; |
| int ret; |
| |
| /* kthread only required for slow path */ |
| if (policy->fast_switch_enabled) |
| return 0; |
| |
| kthread_init_work(&sg_policy->work, sugov_work); |
| kthread_init_worker(&sg_policy->worker); |
| thread = kthread_create(kthread_worker_fn, &sg_policy->worker, |
| "sugov:%d", |
| cpumask_first(policy->related_cpus)); |
| if (IS_ERR(thread)) { |
| pr_err("failed to create sugov thread: %ld\n", PTR_ERR(thread)); |
| return PTR_ERR(thread); |
| } |
| |
| ret = sched_setattr_nocheck(thread, &attr); |
| if (ret) { |
| kthread_stop(thread); |
| pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__); |
| return ret; |
| } |
| |
| sg_policy->thread = thread; |
| kthread_bind_mask(thread, policy->related_cpus); |
| init_irq_work(&sg_policy->irq_work, sugov_irq_work); |
| mutex_init(&sg_policy->work_lock); |
| |
| wake_up_process(thread); |
| |
| return 0; |
| } |
| |
| static void sugov_kthread_stop(struct sugov_policy *sg_policy) |
| { |
| /* kthread only required for slow path */ |
| if (sg_policy->policy->fast_switch_enabled) |
| return; |
| |
| kthread_flush_worker(&sg_policy->worker); |
| kthread_stop(sg_policy->thread); |
| mutex_destroy(&sg_policy->work_lock); |
| } |
| |
| static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_policy) |
| { |
| struct sugov_tunables *tunables; |
| |
| tunables = kzalloc(sizeof(*tunables), GFP_KERNEL); |
| if (tunables) { |
| gov_attr_set_init(&tunables->attr_set, &sg_policy->tunables_hook); |
| if (!have_governor_per_policy()) |
| global_tunables = tunables; |
| } |
| return tunables; |
| } |
| |
| static void sugov_tunables_free(struct sugov_tunables *tunables) |
| { |
| if (!have_governor_per_policy()) |
| global_tunables = NULL; |
| |
| kfree(tunables); |
| } |
| |
| static int sugov_init(struct cpufreq_policy *policy) |
| { |
| struct sugov_policy *sg_policy; |
| struct sugov_tunables *tunables; |
| int ret = 0; |
| |
| /* State should be equivalent to EXIT */ |
| if (policy->governor_data) |
| return -EBUSY; |
| |
| cpufreq_enable_fast_switch(policy); |
| |
| sg_policy = sugov_policy_alloc(policy); |
| if (!sg_policy) { |
| ret = -ENOMEM; |
| goto disable_fast_switch; |
| } |
| |
| ret = sugov_kthread_create(sg_policy); |
| if (ret) |
| goto free_sg_policy; |
| |
| mutex_lock(&global_tunables_lock); |
| |
| if (global_tunables) { |
| if (WARN_ON(have_governor_per_policy())) { |
| ret = -EINVAL; |
| goto stop_kthread; |
| } |
| policy->governor_data = sg_policy; |
| sg_policy->tunables = global_tunables; |
| |
| gov_attr_set_get(&global_tunables->attr_set, &sg_policy->tunables_hook); |
| goto out; |
| } |
| |
| tunables = sugov_tunables_alloc(sg_policy); |
| if (!tunables) { |
| ret = -ENOMEM; |
| goto stop_kthread; |
| } |
| |
| tunables->rate_limit_us = cpufreq_policy_transition_delay_us(policy); |
| |
| policy->governor_data = sg_policy; |
| sg_policy->tunables = tunables; |
| |
| ret = kobject_init_and_add(&tunables->attr_set.kobj, &sugov_tunables_ktype, |
| get_governor_parent_kobj(policy), "%s", |
| schedutil_gov.name); |
| if (ret) |
| goto fail; |
| |
| out: |
| mutex_unlock(&global_tunables_lock); |
| return 0; |
| |
| fail: |
| kobject_put(&tunables->attr_set.kobj); |
| policy->governor_data = NULL; |
| sugov_tunables_free(tunables); |
| |
| stop_kthread: |
| sugov_kthread_stop(sg_policy); |
| mutex_unlock(&global_tunables_lock); |
| |
| free_sg_policy: |
| sugov_policy_free(sg_policy); |
| |
| disable_fast_switch: |
| cpufreq_disable_fast_switch(policy); |
| |
| pr_err("initialization failed (error %d)\n", ret); |
| return ret; |
| } |
| |
| static void sugov_exit(struct cpufreq_policy *policy) |
| { |
| struct sugov_policy *sg_policy = policy->governor_data; |
| struct sugov_tunables *tunables = sg_policy->tunables; |
| unsigned int count; |
| |
| mutex_lock(&global_tunables_lock); |
| |
| count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook); |
| policy->governor_data = NULL; |
| if (!count) |
| sugov_tunables_free(tunables); |
| |
| mutex_unlock(&global_tunables_lock); |
| |
| sugov_kthread_stop(sg_policy); |
| sugov_policy_free(sg_policy); |
| cpufreq_disable_fast_switch(policy); |
| } |
| |
| static int sugov_start(struct cpufreq_policy *policy) |
| { |
| struct sugov_policy *sg_policy = policy->governor_data; |
| unsigned int cpu; |
| |
| sg_policy->freq_update_delay_ns = sg_policy->tunables->rate_limit_us * NSEC_PER_USEC; |
| sg_policy->last_freq_update_time = 0; |
| sg_policy->next_freq = 0; |
| sg_policy->work_in_progress = false; |
| sg_policy->limits_changed = false; |
| sg_policy->need_freq_update = false; |
| sg_policy->cached_raw_freq = 0; |
| |
| for_each_cpu(cpu, policy->cpus) { |
| struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu); |
| |
| memset(sg_cpu, 0, sizeof(*sg_cpu)); |
| sg_cpu->cpu = cpu; |
| sg_cpu->sg_policy = sg_policy; |
| } |
| |
| for_each_cpu(cpu, policy->cpus) { |
| struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu); |
| |
| cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util, |
| policy_is_shared(policy) ? |
| sugov_update_shared : |
| sugov_update_single); |
| } |
| return 0; |
| } |
| |
| static void sugov_stop(struct cpufreq_policy *policy) |
| { |
| struct sugov_policy *sg_policy = policy->governor_data; |
| unsigned int cpu; |
| |
| for_each_cpu(cpu, policy->cpus) |
| cpufreq_remove_update_util_hook(cpu); |
| |
| synchronize_rcu(); |
| |
| if (!policy->fast_switch_enabled) { |
| irq_work_sync(&sg_policy->irq_work); |
| kthread_cancel_work_sync(&sg_policy->work); |
| } |
| } |
| |
| static void sugov_limits(struct cpufreq_policy *policy) |
| { |
| struct sugov_policy *sg_policy = policy->governor_data; |
| |
| if (!policy->fast_switch_enabled) { |
| mutex_lock(&sg_policy->work_lock); |
| cpufreq_policy_apply_limits(policy); |
| mutex_unlock(&sg_policy->work_lock); |
| } |
| |
| sg_policy->limits_changed = true; |
| } |
| |
| struct cpufreq_governor schedutil_gov = { |
| .name = "schedutil", |
| .owner = THIS_MODULE, |
| .dynamic_switching = true, |
| .init = sugov_init, |
| .exit = sugov_exit, |
| .start = sugov_start, |
| .stop = sugov_stop, |
| .limits = sugov_limits, |
| }; |
| |
| #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL |
| struct cpufreq_governor *cpufreq_default_governor(void) |
| { |
| return &schedutil_gov; |
| } |
| #endif |
| |
| static int __init sugov_register(void) |
| { |
| return cpufreq_register_governor(&schedutil_gov); |
| } |
| core_initcall(sugov_register); |
| |
| #ifdef CONFIG_ENERGY_MODEL |
| extern bool sched_energy_update; |
| extern struct mutex sched_energy_mutex; |
| |
| static void rebuild_sd_workfn(struct work_struct *work) |
| { |
| mutex_lock(&sched_energy_mutex); |
| sched_energy_update = true; |
| rebuild_sched_domains(); |
| sched_energy_update = false; |
| mutex_unlock(&sched_energy_mutex); |
| } |
| static DECLARE_WORK(rebuild_sd_work, rebuild_sd_workfn); |
| |
| /* |
| * EAS shouldn't be attempted without sugov, so rebuild the sched_domains |
| * on governor changes to make sure the scheduler knows about it. |
| */ |
| void sched_cpufreq_governor_change(struct cpufreq_policy *policy, |
| struct cpufreq_governor *old_gov) |
| { |
| if (old_gov == &schedutil_gov || policy->governor == &schedutil_gov) { |
| /* |
| * When called from the cpufreq_register_driver() path, the |
| * cpu_hotplug_lock is already held, so use a work item to |
| * avoid nested locking in rebuild_sched_domains(). |
| */ |
| schedule_work(&rebuild_sd_work); |
| } |
| |
| } |
| #endif |