1 // SPDX-License-Identifier: GPL-2.0
3 * CPUFreq governor based on scheduler-provided CPU utilization data.
5 * Copyright (C) 2016, Intel Corporation
6 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/sched/cpufreq.h>
14 #include <trace/events/power.h>
16 #define IOWAIT_BOOST_MIN (SCHED_CAPACITY_SCALE / 8)
18 struct sugov_tunables {
19 struct gov_attr_set attr_set;
20 unsigned int rate_limit_us;
24 struct cpufreq_policy *policy;
26 struct sugov_tunables *tunables;
27 struct list_head tunables_hook;
29 raw_spinlock_t update_lock; /* For shared policies */
30 u64 last_freq_update_time;
31 s64 freq_update_delay_ns;
32 unsigned int next_freq;
33 unsigned int cached_raw_freq;
35 /* The next fields are only needed if fast switch cannot be used: */
36 struct irq_work irq_work;
37 struct kthread_work work;
38 struct mutex work_lock;
39 struct kthread_worker worker;
40 struct task_struct *thread;
41 bool work_in_progress;
44 bool need_freq_update;
48 struct update_util_data update_util;
49 struct sugov_policy *sg_policy;
52 bool iowait_boost_pending;
53 unsigned int iowait_boost;
59 /* The field below is for single-CPU policies only: */
60 #ifdef CONFIG_NO_HZ_COMMON
61 unsigned long saved_idle_calls;
65 static DEFINE_PER_CPU(struct sugov_cpu, sugov_cpu);
67 /************************ Governor internals ***********************/
69 static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time)
74 * Since cpufreq_update_util() is called with rq->lock held for
75 * the @target_cpu, our per-CPU data is fully serialized.
77 * However, drivers cannot in general deal with cross-CPU
78 * requests, so while get_next_freq() will work, our
79 * sugov_update_commit() call may not for the fast switching platforms.
81 * Hence stop here for remote requests if they aren't supported
82 * by the hardware, as calculating the frequency is pointless if
83 * we cannot in fact act on it.
85 * This is needed on the slow switching platforms too to prevent CPUs
86 * going offline from leaving stale IRQ work items behind.
88 if (!cpufreq_this_cpu_can_update(sg_policy->policy))
91 if (unlikely(sg_policy->limits_changed)) {
92 sg_policy->limits_changed = false;
93 sg_policy->need_freq_update = true;
97 delta_ns = time - sg_policy->last_freq_update_time;
99 return delta_ns >= sg_policy->freq_update_delay_ns;
102 static bool sugov_update_next_freq(struct sugov_policy *sg_policy, u64 time,
103 unsigned int next_freq)
105 if (sg_policy->next_freq == next_freq)
108 sg_policy->next_freq = next_freq;
109 sg_policy->last_freq_update_time = time;
114 static void sugov_fast_switch(struct sugov_policy *sg_policy, u64 time,
115 unsigned int next_freq)
117 struct cpufreq_policy *policy = sg_policy->policy;
120 if (!sugov_update_next_freq(sg_policy, time, next_freq))
123 next_freq = cpufreq_driver_fast_switch(policy, next_freq);
127 policy->cur = next_freq;
129 if (trace_cpu_frequency_enabled()) {
130 for_each_cpu(cpu, policy->cpus)
131 trace_cpu_frequency(next_freq, cpu);
135 static void sugov_deferred_update(struct sugov_policy *sg_policy, u64 time,
136 unsigned int next_freq)
138 if (!sugov_update_next_freq(sg_policy, time, next_freq))
141 if (!sg_policy->work_in_progress) {
142 sg_policy->work_in_progress = true;
143 irq_work_queue(&sg_policy->irq_work);
148 * get_next_freq - Compute a new frequency for a given cpufreq policy.
149 * @sg_policy: schedutil policy object to compute the new frequency for.
150 * @util: Current CPU utilization.
151 * @max: CPU capacity.
153 * If the utilization is frequency-invariant, choose the new frequency to be
154 * proportional to it, that is
156 * next_freq = C * max_freq * util / max
158 * Otherwise, approximate the would-be frequency-invariant utilization by
159 * util_raw * (curr_freq / max_freq) which leads to
161 * next_freq = C * curr_freq * util_raw / max
163 * Take C = 1.25 for the frequency tipping point at (util / max) = 0.8.
165 * The lowest driver-supported frequency which is equal or greater than the raw
166 * next_freq (as calculated above) is returned, subject to policy min/max and
167 * cpufreq driver limitations.
169 static unsigned int get_next_freq(struct sugov_policy *sg_policy,
170 unsigned long util, unsigned long max)
172 struct cpufreq_policy *policy = sg_policy->policy;
173 unsigned int freq = arch_scale_freq_invariant() ?
174 policy->cpuinfo.max_freq : policy->cur;
176 freq = map_util_freq(util, freq, max);
178 if (freq == sg_policy->cached_raw_freq && !sg_policy->need_freq_update)
179 return sg_policy->next_freq;
181 sg_policy->need_freq_update = false;
182 sg_policy->cached_raw_freq = freq;
183 return cpufreq_driver_resolve_freq(policy, freq);
187 * This function computes an effective utilization for the given CPU, to be
188 * used for frequency selection given the linear relation: f = u * f_max.
190 * The scheduler tracks the following metrics:
192 * cpu_util_{cfs,rt,dl,irq}()
195 * Where the cfs,rt and dl util numbers are tracked with the same metric and
196 * synchronized windows and are thus directly comparable.
198 * The cfs,rt,dl utilization are the running times measured with rq->clock_task
199 * which excludes things like IRQ and steal-time. These latter are then accrued
200 * in the irq utilization.
202 * The DL bandwidth number otoh is not a measured metric but a value computed
203 * based on the task model parameters and gives the minimal utilization
204 * required to meet deadlines.
206 unsigned long schedutil_cpu_util(int cpu, unsigned long util_cfs,
207 unsigned long max, enum schedutil_type type,
208 struct task_struct *p)
210 unsigned long dl_util, util, irq;
211 struct rq *rq = cpu_rq(cpu);
213 if (!uclamp_is_used() &&
214 type == FREQUENCY_UTIL && rt_rq_is_runnable(&rq->rt)) {
219 * Early check to see if IRQ/steal time saturates the CPU, can be
220 * because of inaccuracies in how we track these -- see
221 * update_irq_load_avg().
223 irq = cpu_util_irq(rq);
224 if (unlikely(irq >= max))
228 * Because the time spend on RT/DL tasks is visible as 'lost' time to
229 * CFS tasks and we use the same metric to track the effective
230 * utilization (PELT windows are synchronized) we can directly add them
231 * to obtain the CPU's actual utilization.
233 * CFS and RT utilization can be boosted or capped, depending on
234 * utilization clamp constraints requested by currently RUNNABLE
236 * When there are no CFS RUNNABLE tasks, clamps are released and
237 * frequency will be gracefully reduced with the utilization decay.
239 util = util_cfs + cpu_util_rt(rq);
240 if (type == FREQUENCY_UTIL)
241 util = uclamp_util_with(rq, util, p);
243 dl_util = cpu_util_dl(rq);
246 * For frequency selection we do not make cpu_util_dl() a permanent part
247 * of this sum because we want to use cpu_bw_dl() later on, but we need
248 * to check if the CFS+RT+DL sum is saturated (ie. no idle time) such
249 * that we select f_max when there is no idle time.
251 * NOTE: numerical errors or stop class might cause us to not quite hit
252 * saturation when we should -- something for later.
254 if (util + dl_util >= max)
258 * OTOH, for energy computation we need the estimated running time, so
259 * include util_dl and ignore dl_bw.
261 if (type == ENERGY_UTIL)
265 * There is still idle time; further improve the number by using the
266 * irq metric. Because IRQ/steal time is hidden from the task clock we
267 * need to scale the task numbers:
270 * U' = irq + --------- * U
273 util = scale_irq_capacity(util, irq, max);
277 * Bandwidth required by DEADLINE must always be granted while, for
278 * FAIR and RT, we use blocked utilization of IDLE CPUs as a mechanism
279 * to gracefully reduce the frequency when no tasks show up for longer
282 * Ideally we would like to set bw_dl as min/guaranteed freq and util +
283 * bw_dl as requested freq. However, cpufreq is not yet ready for such
284 * an interface. So, we only do the latter for now.
286 if (type == FREQUENCY_UTIL)
287 util += cpu_bw_dl(rq);
289 return min(max, util);
292 static unsigned long sugov_get_util(struct sugov_cpu *sg_cpu)
294 struct rq *rq = cpu_rq(sg_cpu->cpu);
295 unsigned long util = cpu_util_cfs(rq);
296 unsigned long max = arch_scale_cpu_capacity(sg_cpu->cpu);
299 sg_cpu->bw_dl = cpu_bw_dl(rq);
301 return schedutil_cpu_util(sg_cpu->cpu, util, max, FREQUENCY_UTIL, NULL);
305 * sugov_iowait_reset() - Reset the IO boost status of a CPU.
306 * @sg_cpu: the sugov data for the CPU to boost
307 * @time: the update time from the caller
308 * @set_iowait_boost: true if an IO boost has been requested
310 * The IO wait boost of a task is disabled after a tick since the last update
311 * of a CPU. If a new IO wait boost is requested after more then a tick, then
312 * we enable the boost starting from IOWAIT_BOOST_MIN, which improves energy
313 * efficiency by ignoring sporadic wakeups from IO.
315 static bool sugov_iowait_reset(struct sugov_cpu *sg_cpu, u64 time,
316 bool set_iowait_boost)
318 s64 delta_ns = time - sg_cpu->last_update;
320 /* Reset boost only if a tick has elapsed since last request */
321 if (delta_ns <= TICK_NSEC)
324 sg_cpu->iowait_boost = set_iowait_boost ? IOWAIT_BOOST_MIN : 0;
325 sg_cpu->iowait_boost_pending = set_iowait_boost;
331 * sugov_iowait_boost() - Updates the IO boost status of a CPU.
332 * @sg_cpu: the sugov data for the CPU to boost
333 * @time: the update time from the caller
334 * @flags: SCHED_CPUFREQ_IOWAIT if the task is waking up after an IO wait
336 * Each time a task wakes up after an IO operation, the CPU utilization can be
337 * boosted to a certain utilization which doubles at each "frequent and
338 * successive" wakeup from IO, ranging from IOWAIT_BOOST_MIN to the utilization
339 * of the maximum OPP.
341 * To keep doubling, an IO boost has to be requested at least once per tick,
342 * otherwise we restart from the utilization of the minimum OPP.
344 static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
347 bool set_iowait_boost = flags & SCHED_CPUFREQ_IOWAIT;
349 /* Reset boost if the CPU appears to have been idle enough */
350 if (sg_cpu->iowait_boost &&
351 sugov_iowait_reset(sg_cpu, time, set_iowait_boost))
354 /* Boost only tasks waking up after IO */
355 if (!set_iowait_boost)
358 /* Ensure boost doubles only one time at each request */
359 if (sg_cpu->iowait_boost_pending)
361 sg_cpu->iowait_boost_pending = true;
363 /* Double the boost at each request */
364 if (sg_cpu->iowait_boost) {
365 sg_cpu->iowait_boost =
366 min_t(unsigned int, sg_cpu->iowait_boost << 1, SCHED_CAPACITY_SCALE);
370 /* First wakeup after IO: start with minimum boost */
371 sg_cpu->iowait_boost = IOWAIT_BOOST_MIN;
375 * sugov_iowait_apply() - Apply the IO boost to a CPU.
376 * @sg_cpu: the sugov data for the cpu to boost
377 * @time: the update time from the caller
378 * @util: the utilization to (eventually) boost
379 * @max: the maximum value the utilization can be boosted to
381 * A CPU running a task which woken up after an IO operation can have its
382 * utilization boosted to speed up the completion of those IO operations.
383 * The IO boost value is increased each time a task wakes up from IO, in
384 * sugov_iowait_apply(), and it's instead decreased by this function,
385 * each time an increase has not been requested (!iowait_boost_pending).
387 * A CPU which also appears to have been idle for at least one tick has also
388 * its IO boost utilization reset.
390 * This mechanism is designed to boost high frequently IO waiting tasks, while
391 * being more conservative on tasks which does sporadic IO operations.
393 static unsigned long sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time,
394 unsigned long util, unsigned long max)
398 /* No boost currently required */
399 if (!sg_cpu->iowait_boost)
402 /* Reset boost if the CPU appears to have been idle enough */
403 if (sugov_iowait_reset(sg_cpu, time, false))
406 if (!sg_cpu->iowait_boost_pending) {
408 * No boost pending; reduce the boost value.
410 sg_cpu->iowait_boost >>= 1;
411 if (sg_cpu->iowait_boost < IOWAIT_BOOST_MIN) {
412 sg_cpu->iowait_boost = 0;
417 sg_cpu->iowait_boost_pending = false;
420 * @util is already in capacity scale; convert iowait_boost
421 * into the same scale so we can compare.
423 boost = (sg_cpu->iowait_boost * max) >> SCHED_CAPACITY_SHIFT;
424 return max(boost, util);
427 #ifdef CONFIG_NO_HZ_COMMON
428 static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu)
430 unsigned long idle_calls = tick_nohz_get_idle_calls_cpu(sg_cpu->cpu);
431 bool ret = idle_calls == sg_cpu->saved_idle_calls;
433 sg_cpu->saved_idle_calls = idle_calls;
437 static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
438 #endif /* CONFIG_NO_HZ_COMMON */
441 * Make sugov_should_update_freq() ignore the rate limit when DL
442 * has increased the utilization.
444 static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu, struct sugov_policy *sg_policy)
446 if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_dl)
447 sg_policy->limits_changed = true;
450 static void sugov_update_single(struct update_util_data *hook, u64 time,
453 struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
454 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
455 unsigned long util, max;
459 sugov_iowait_boost(sg_cpu, time, flags);
460 sg_cpu->last_update = time;
462 ignore_dl_rate_limit(sg_cpu, sg_policy);
464 if (!sugov_should_update_freq(sg_policy, time))
467 /* Limits may have changed, don't skip frequency update */
468 busy = !sg_policy->need_freq_update && sugov_cpu_is_busy(sg_cpu);
470 util = sugov_get_util(sg_cpu);
472 util = sugov_iowait_apply(sg_cpu, time, util, max);
473 next_f = get_next_freq(sg_policy, util, max);
475 * Do not reduce the frequency if the CPU has not been idle
476 * recently, as the reduction is likely to be premature then.
478 if (busy && next_f < sg_policy->next_freq) {
479 next_f = sg_policy->next_freq;
481 /* Reset cached freq as next_freq has changed */
482 sg_policy->cached_raw_freq = 0;
486 * This code runs under rq->lock for the target CPU, so it won't run
487 * concurrently on two different CPUs for the same target and it is not
488 * necessary to acquire the lock in the fast switch case.
490 if (sg_policy->policy->fast_switch_enabled) {
491 sugov_fast_switch(sg_policy, time, next_f);
493 raw_spin_lock(&sg_policy->update_lock);
494 sugov_deferred_update(sg_policy, time, next_f);
495 raw_spin_unlock(&sg_policy->update_lock);
499 static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
501 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
502 struct cpufreq_policy *policy = sg_policy->policy;
503 unsigned long util = 0, max = 1;
506 for_each_cpu(j, policy->cpus) {
507 struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
508 unsigned long j_util, j_max;
510 j_util = sugov_get_util(j_sg_cpu);
511 j_max = j_sg_cpu->max;
512 j_util = sugov_iowait_apply(j_sg_cpu, time, j_util, j_max);
514 if (j_util * max > j_max * util) {
520 return get_next_freq(sg_policy, util, max);
524 sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int flags)
526 struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
527 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
530 raw_spin_lock(&sg_policy->update_lock);
532 sugov_iowait_boost(sg_cpu, time, flags);
533 sg_cpu->last_update = time;
535 ignore_dl_rate_limit(sg_cpu, sg_policy);
537 if (sugov_should_update_freq(sg_policy, time)) {
538 next_f = sugov_next_freq_shared(sg_cpu, time);
540 if (sg_policy->policy->fast_switch_enabled)
541 sugov_fast_switch(sg_policy, time, next_f);
543 sugov_deferred_update(sg_policy, time, next_f);
546 raw_spin_unlock(&sg_policy->update_lock);
549 static void sugov_work(struct kthread_work *work)
551 struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work);
556 * Hold sg_policy->update_lock shortly to handle the case where:
557 * incase sg_policy->next_freq is read here, and then updated by
558 * sugov_deferred_update() just before work_in_progress is set to false
559 * here, we may miss queueing the new update.
561 * Note: If a work was queued after the update_lock is released,
562 * sugov_work() will just be called again by kthread_work code; and the
563 * request will be proceed before the sugov thread sleeps.
565 raw_spin_lock_irqsave(&sg_policy->update_lock, flags);
566 freq = sg_policy->next_freq;
567 sg_policy->work_in_progress = false;
568 raw_spin_unlock_irqrestore(&sg_policy->update_lock, flags);
570 mutex_lock(&sg_policy->work_lock);
571 __cpufreq_driver_target(sg_policy->policy, freq, CPUFREQ_RELATION_L);
572 mutex_unlock(&sg_policy->work_lock);
575 static void sugov_irq_work(struct irq_work *irq_work)
577 struct sugov_policy *sg_policy;
579 sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
581 kthread_queue_work(&sg_policy->worker, &sg_policy->work);
584 /************************** sysfs interface ************************/
586 static struct sugov_tunables *global_tunables;
587 static DEFINE_MUTEX(global_tunables_lock);
589 static inline struct sugov_tunables *to_sugov_tunables(struct gov_attr_set *attr_set)
591 return container_of(attr_set, struct sugov_tunables, attr_set);
594 static ssize_t rate_limit_us_show(struct gov_attr_set *attr_set, char *buf)
596 struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
598 return sprintf(buf, "%u\n", tunables->rate_limit_us);
602 rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf, size_t count)
604 struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
605 struct sugov_policy *sg_policy;
606 unsigned int rate_limit_us;
608 if (kstrtouint(buf, 10, &rate_limit_us))
611 tunables->rate_limit_us = rate_limit_us;
613 list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook)
614 sg_policy->freq_update_delay_ns = rate_limit_us * NSEC_PER_USEC;
619 static struct governor_attr rate_limit_us = __ATTR_RW(rate_limit_us);
621 static struct attribute *sugov_attrs[] = {
625 ATTRIBUTE_GROUPS(sugov);
627 static void sugov_tunables_free(struct kobject *kobj)
629 struct gov_attr_set *attr_set = container_of(kobj, struct gov_attr_set, kobj);
631 kfree(to_sugov_tunables(attr_set));
634 static struct kobj_type sugov_tunables_ktype = {
635 .default_groups = sugov_groups,
636 .sysfs_ops = &governor_sysfs_ops,
637 .release = &sugov_tunables_free,
640 /********************** cpufreq governor interface *********************/
642 struct cpufreq_governor schedutil_gov;
644 static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy)
646 struct sugov_policy *sg_policy;
648 sg_policy = kzalloc(sizeof(*sg_policy), GFP_KERNEL);
652 sg_policy->policy = policy;
653 raw_spin_lock_init(&sg_policy->update_lock);
657 static void sugov_policy_free(struct sugov_policy *sg_policy)
662 static int sugov_kthread_create(struct sugov_policy *sg_policy)
664 struct task_struct *thread;
665 struct sched_attr attr = {
666 .size = sizeof(struct sched_attr),
667 .sched_policy = SCHED_DEADLINE,
668 .sched_flags = SCHED_FLAG_SUGOV,
672 * Fake (unused) bandwidth; workaround to "fix"
673 * priority inheritance.
675 .sched_runtime = 1000000,
676 .sched_deadline = 10000000,
677 .sched_period = 10000000,
679 struct cpufreq_policy *policy = sg_policy->policy;
682 /* kthread only required for slow path */
683 if (policy->fast_switch_enabled)
686 kthread_init_work(&sg_policy->work, sugov_work);
687 kthread_init_worker(&sg_policy->worker);
688 thread = kthread_create(kthread_worker_fn, &sg_policy->worker,
690 cpumask_first(policy->related_cpus));
691 if (IS_ERR(thread)) {
692 pr_err("failed to create sugov thread: %ld\n", PTR_ERR(thread));
693 return PTR_ERR(thread);
696 ret = sched_setattr_nocheck(thread, &attr);
698 kthread_stop(thread);
699 pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
703 sg_policy->thread = thread;
704 kthread_bind_mask(thread, policy->related_cpus);
705 init_irq_work(&sg_policy->irq_work, sugov_irq_work);
706 mutex_init(&sg_policy->work_lock);
708 wake_up_process(thread);
713 static void sugov_kthread_stop(struct sugov_policy *sg_policy)
715 /* kthread only required for slow path */
716 if (sg_policy->policy->fast_switch_enabled)
719 kthread_flush_worker(&sg_policy->worker);
720 kthread_stop(sg_policy->thread);
721 mutex_destroy(&sg_policy->work_lock);
724 static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_policy)
726 struct sugov_tunables *tunables;
728 tunables = kzalloc(sizeof(*tunables), GFP_KERNEL);
730 gov_attr_set_init(&tunables->attr_set, &sg_policy->tunables_hook);
731 if (!have_governor_per_policy())
732 global_tunables = tunables;
737 static void sugov_clear_global_tunables(void)
739 if (!have_governor_per_policy())
740 global_tunables = NULL;
743 static int sugov_init(struct cpufreq_policy *policy)
745 struct sugov_policy *sg_policy;
746 struct sugov_tunables *tunables;
749 /* State should be equivalent to EXIT */
750 if (policy->governor_data)
753 cpufreq_enable_fast_switch(policy);
755 sg_policy = sugov_policy_alloc(policy);
758 goto disable_fast_switch;
761 ret = sugov_kthread_create(sg_policy);
765 mutex_lock(&global_tunables_lock);
767 if (global_tunables) {
768 if (WARN_ON(have_governor_per_policy())) {
772 policy->governor_data = sg_policy;
773 sg_policy->tunables = global_tunables;
775 gov_attr_set_get(&global_tunables->attr_set, &sg_policy->tunables_hook);
779 tunables = sugov_tunables_alloc(sg_policy);
785 tunables->rate_limit_us = cpufreq_policy_transition_delay_us(policy);
787 policy->governor_data = sg_policy;
788 sg_policy->tunables = tunables;
790 ret = kobject_init_and_add(&tunables->attr_set.kobj, &sugov_tunables_ktype,
791 get_governor_parent_kobj(policy), "%s",
797 mutex_unlock(&global_tunables_lock);
801 kobject_put(&tunables->attr_set.kobj);
802 policy->governor_data = NULL;
803 sugov_clear_global_tunables();
806 sugov_kthread_stop(sg_policy);
807 mutex_unlock(&global_tunables_lock);
810 sugov_policy_free(sg_policy);
813 cpufreq_disable_fast_switch(policy);
815 pr_err("initialization failed (error %d)\n", ret);
819 static void sugov_exit(struct cpufreq_policy *policy)
821 struct sugov_policy *sg_policy = policy->governor_data;
822 struct sugov_tunables *tunables = sg_policy->tunables;
825 mutex_lock(&global_tunables_lock);
827 count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);
828 policy->governor_data = NULL;
830 sugov_clear_global_tunables();
832 mutex_unlock(&global_tunables_lock);
834 sugov_kthread_stop(sg_policy);
835 sugov_policy_free(sg_policy);
836 cpufreq_disable_fast_switch(policy);
839 static int sugov_start(struct cpufreq_policy *policy)
841 struct sugov_policy *sg_policy = policy->governor_data;
844 sg_policy->freq_update_delay_ns = sg_policy->tunables->rate_limit_us * NSEC_PER_USEC;
845 sg_policy->last_freq_update_time = 0;
846 sg_policy->next_freq = 0;
847 sg_policy->work_in_progress = false;
848 sg_policy->limits_changed = false;
849 sg_policy->need_freq_update = false;
850 sg_policy->cached_raw_freq = 0;
852 for_each_cpu(cpu, policy->cpus) {
853 struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
855 memset(sg_cpu, 0, sizeof(*sg_cpu));
857 sg_cpu->sg_policy = sg_policy;
860 for_each_cpu(cpu, policy->cpus) {
861 struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
863 cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util,
864 policy_is_shared(policy) ?
865 sugov_update_shared :
866 sugov_update_single);
871 static void sugov_stop(struct cpufreq_policy *policy)
873 struct sugov_policy *sg_policy = policy->governor_data;
876 for_each_cpu(cpu, policy->cpus)
877 cpufreq_remove_update_util_hook(cpu);
881 if (!policy->fast_switch_enabled) {
882 irq_work_sync(&sg_policy->irq_work);
883 kthread_cancel_work_sync(&sg_policy->work);
887 static void sugov_limits(struct cpufreq_policy *policy)
889 struct sugov_policy *sg_policy = policy->governor_data;
891 if (!policy->fast_switch_enabled) {
892 mutex_lock(&sg_policy->work_lock);
893 cpufreq_policy_apply_limits(policy);
894 mutex_unlock(&sg_policy->work_lock);
897 sg_policy->limits_changed = true;
900 struct cpufreq_governor schedutil_gov = {
902 .owner = THIS_MODULE,
903 .dynamic_switching = true,
906 .start = sugov_start,
908 .limits = sugov_limits,
911 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
912 struct cpufreq_governor *cpufreq_default_governor(void)
914 return &schedutil_gov;
918 static int __init sugov_register(void)
920 return cpufreq_register_governor(&schedutil_gov);
922 fs_initcall(sugov_register);
924 #ifdef CONFIG_ENERGY_MODEL
925 extern bool sched_energy_update;
926 extern struct mutex sched_energy_mutex;
928 static void rebuild_sd_workfn(struct work_struct *work)
930 mutex_lock(&sched_energy_mutex);
931 sched_energy_update = true;
932 rebuild_sched_domains();
933 sched_energy_update = false;
934 mutex_unlock(&sched_energy_mutex);
936 static DECLARE_WORK(rebuild_sd_work, rebuild_sd_workfn);
939 * EAS shouldn't be attempted without sugov, so rebuild the sched_domains
940 * on governor changes to make sure the scheduler knows about it.
942 void sched_cpufreq_governor_change(struct cpufreq_policy *policy,
943 struct cpufreq_governor *old_gov)
945 if (old_gov == &schedutil_gov || policy->governor == &schedutil_gov) {
947 * When called from the cpufreq_register_driver() path, the
948 * cpu_hotplug_lock is already held, so use a work item to
949 * avoid nested locking in rebuild_sched_domains().
951 schedule_work(&rebuild_sd_work);