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 * For the slow switching platforms, the kthread is always scheduled on
86 * the right set of CPUs and any CPU can find the next frequency and
87 * schedule the kthread.
89 if (sg_policy->policy->fast_switch_enabled &&
90 !cpufreq_this_cpu_can_update(sg_policy->policy))
93 if (unlikely(sg_policy->limits_changed)) {
94 sg_policy->limits_changed = false;
95 sg_policy->need_freq_update = true;
99 delta_ns = time - sg_policy->last_freq_update_time;
101 return delta_ns >= sg_policy->freq_update_delay_ns;
104 static bool sugov_update_next_freq(struct sugov_policy *sg_policy, u64 time,
105 unsigned int next_freq)
107 if (sg_policy->next_freq == next_freq)
110 sg_policy->next_freq = next_freq;
111 sg_policy->last_freq_update_time = time;
116 static void sugov_fast_switch(struct sugov_policy *sg_policy, u64 time,
117 unsigned int next_freq)
119 struct cpufreq_policy *policy = sg_policy->policy;
121 if (!sugov_update_next_freq(sg_policy, time, next_freq))
124 next_freq = cpufreq_driver_fast_switch(policy, next_freq);
128 policy->cur = next_freq;
129 trace_cpu_frequency(next_freq, smp_processor_id());
132 static void sugov_deferred_update(struct sugov_policy *sg_policy, u64 time,
133 unsigned int next_freq)
135 if (!sugov_update_next_freq(sg_policy, time, next_freq))
138 if (!sg_policy->work_in_progress) {
139 sg_policy->work_in_progress = true;
140 irq_work_queue(&sg_policy->irq_work);
145 * get_next_freq - Compute a new frequency for a given cpufreq policy.
146 * @sg_policy: schedutil policy object to compute the new frequency for.
147 * @util: Current CPU utilization.
148 * @max: CPU capacity.
150 * If the utilization is frequency-invariant, choose the new frequency to be
151 * proportional to it, that is
153 * next_freq = C * max_freq * util / max
155 * Otherwise, approximate the would-be frequency-invariant utilization by
156 * util_raw * (curr_freq / max_freq) which leads to
158 * next_freq = C * curr_freq * util_raw / max
160 * Take C = 1.25 for the frequency tipping point at (util / max) = 0.8.
162 * The lowest driver-supported frequency which is equal or greater than the raw
163 * next_freq (as calculated above) is returned, subject to policy min/max and
164 * cpufreq driver limitations.
166 static unsigned int get_next_freq(struct sugov_policy *sg_policy,
167 unsigned long util, unsigned long max)
169 struct cpufreq_policy *policy = sg_policy->policy;
170 unsigned int freq = arch_scale_freq_invariant() ?
171 policy->cpuinfo.max_freq : policy->cur;
173 freq = map_util_freq(util, freq, max);
175 if (freq == sg_policy->cached_raw_freq && !sg_policy->need_freq_update)
176 return sg_policy->next_freq;
178 sg_policy->need_freq_update = false;
179 sg_policy->cached_raw_freq = freq;
180 return cpufreq_driver_resolve_freq(policy, freq);
184 * This function computes an effective utilization for the given CPU, to be
185 * used for frequency selection given the linear relation: f = u * f_max.
187 * The scheduler tracks the following metrics:
189 * cpu_util_{cfs,rt,dl,irq}()
192 * Where the cfs,rt and dl util numbers are tracked with the same metric and
193 * synchronized windows and are thus directly comparable.
195 * The cfs,rt,dl utilization are the running times measured with rq->clock_task
196 * which excludes things like IRQ and steal-time. These latter are then accrued
197 * in the irq utilization.
199 * The DL bandwidth number otoh is not a measured metric but a value computed
200 * based on the task model parameters and gives the minimal utilization
201 * required to meet deadlines.
203 unsigned long schedutil_cpu_util(int cpu, unsigned long util_cfs,
204 unsigned long max, enum schedutil_type type,
205 struct task_struct *p)
207 unsigned long dl_util, util, irq;
208 struct rq *rq = cpu_rq(cpu);
210 if (!IS_BUILTIN(CONFIG_UCLAMP_TASK) &&
211 type == FREQUENCY_UTIL && rt_rq_is_runnable(&rq->rt)) {
216 * Early check to see if IRQ/steal time saturates the CPU, can be
217 * because of inaccuracies in how we track these -- see
218 * update_irq_load_avg().
220 irq = cpu_util_irq(rq);
221 if (unlikely(irq >= max))
225 * Because the time spend on RT/DL tasks is visible as 'lost' time to
226 * CFS tasks and we use the same metric to track the effective
227 * utilization (PELT windows are synchronized) we can directly add them
228 * to obtain the CPU's actual utilization.
230 * CFS and RT utilization can be boosted or capped, depending on
231 * utilization clamp constraints requested by currently RUNNABLE
233 * When there are no CFS RUNNABLE tasks, clamps are released and
234 * frequency will be gracefully reduced with the utilization decay.
236 util = util_cfs + cpu_util_rt(rq);
237 if (type == FREQUENCY_UTIL)
238 util = uclamp_util_with(rq, util, p);
240 dl_util = cpu_util_dl(rq);
243 * For frequency selection we do not make cpu_util_dl() a permanent part
244 * of this sum because we want to use cpu_bw_dl() later on, but we need
245 * to check if the CFS+RT+DL sum is saturated (ie. no idle time) such
246 * that we select f_max when there is no idle time.
248 * NOTE: numerical errors or stop class might cause us to not quite hit
249 * saturation when we should -- something for later.
251 if (util + dl_util >= max)
255 * OTOH, for energy computation we need the estimated running time, so
256 * include util_dl and ignore dl_bw.
258 if (type == ENERGY_UTIL)
262 * There is still idle time; further improve the number by using the
263 * irq metric. Because IRQ/steal time is hidden from the task clock we
264 * need to scale the task numbers:
267 * U' = irq + ------- * U
270 util = scale_irq_capacity(util, irq, max);
274 * Bandwidth required by DEADLINE must always be granted while, for
275 * FAIR and RT, we use blocked utilization of IDLE CPUs as a mechanism
276 * to gracefully reduce the frequency when no tasks show up for longer
279 * Ideally we would like to set bw_dl as min/guaranteed freq and util +
280 * bw_dl as requested freq. However, cpufreq is not yet ready for such
281 * an interface. So, we only do the latter for now.
283 if (type == FREQUENCY_UTIL)
284 util += cpu_bw_dl(rq);
286 return min(max, util);
289 static unsigned long sugov_get_util(struct sugov_cpu *sg_cpu)
291 struct rq *rq = cpu_rq(sg_cpu->cpu);
292 unsigned long util = cpu_util_cfs(rq);
293 unsigned long max = arch_scale_cpu_capacity(sg_cpu->cpu);
296 sg_cpu->bw_dl = cpu_bw_dl(rq);
298 return schedutil_cpu_util(sg_cpu->cpu, util, max, FREQUENCY_UTIL, NULL);
302 * sugov_iowait_reset() - Reset the IO boost status of a CPU.
303 * @sg_cpu: the sugov data for the CPU to boost
304 * @time: the update time from the caller
305 * @set_iowait_boost: true if an IO boost has been requested
307 * The IO wait boost of a task is disabled after a tick since the last update
308 * of a CPU. If a new IO wait boost is requested after more then a tick, then
309 * we enable the boost starting from IOWAIT_BOOST_MIN, which improves energy
310 * efficiency by ignoring sporadic wakeups from IO.
312 static bool sugov_iowait_reset(struct sugov_cpu *sg_cpu, u64 time,
313 bool set_iowait_boost)
315 s64 delta_ns = time - sg_cpu->last_update;
317 /* Reset boost only if a tick has elapsed since last request */
318 if (delta_ns <= TICK_NSEC)
321 sg_cpu->iowait_boost = set_iowait_boost ? IOWAIT_BOOST_MIN : 0;
322 sg_cpu->iowait_boost_pending = set_iowait_boost;
328 * sugov_iowait_boost() - Updates the IO boost status of a CPU.
329 * @sg_cpu: the sugov data for the CPU to boost
330 * @time: the update time from the caller
331 * @flags: SCHED_CPUFREQ_IOWAIT if the task is waking up after an IO wait
333 * Each time a task wakes up after an IO operation, the CPU utilization can be
334 * boosted to a certain utilization which doubles at each "frequent and
335 * successive" wakeup from IO, ranging from IOWAIT_BOOST_MIN to the utilization
336 * of the maximum OPP.
338 * To keep doubling, an IO boost has to be requested at least once per tick,
339 * otherwise we restart from the utilization of the minimum OPP.
341 static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
344 bool set_iowait_boost = flags & SCHED_CPUFREQ_IOWAIT;
346 /* Reset boost if the CPU appears to have been idle enough */
347 if (sg_cpu->iowait_boost &&
348 sugov_iowait_reset(sg_cpu, time, set_iowait_boost))
351 /* Boost only tasks waking up after IO */
352 if (!set_iowait_boost)
355 /* Ensure boost doubles only one time at each request */
356 if (sg_cpu->iowait_boost_pending)
358 sg_cpu->iowait_boost_pending = true;
360 /* Double the boost at each request */
361 if (sg_cpu->iowait_boost) {
362 sg_cpu->iowait_boost =
363 min_t(unsigned int, sg_cpu->iowait_boost << 1, SCHED_CAPACITY_SCALE);
367 /* First wakeup after IO: start with minimum boost */
368 sg_cpu->iowait_boost = IOWAIT_BOOST_MIN;
372 * sugov_iowait_apply() - Apply the IO boost to a CPU.
373 * @sg_cpu: the sugov data for the cpu to boost
374 * @time: the update time from the caller
375 * @util: the utilization to (eventually) boost
376 * @max: the maximum value the utilization can be boosted to
378 * A CPU running a task which woken up after an IO operation can have its
379 * utilization boosted to speed up the completion of those IO operations.
380 * The IO boost value is increased each time a task wakes up from IO, in
381 * sugov_iowait_apply(), and it's instead decreased by this function,
382 * each time an increase has not been requested (!iowait_boost_pending).
384 * A CPU which also appears to have been idle for at least one tick has also
385 * its IO boost utilization reset.
387 * This mechanism is designed to boost high frequently IO waiting tasks, while
388 * being more conservative on tasks which does sporadic IO operations.
390 static unsigned long sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time,
391 unsigned long util, unsigned long max)
395 /* No boost currently required */
396 if (!sg_cpu->iowait_boost)
399 /* Reset boost if the CPU appears to have been idle enough */
400 if (sugov_iowait_reset(sg_cpu, time, false))
403 if (!sg_cpu->iowait_boost_pending) {
405 * No boost pending; reduce the boost value.
407 sg_cpu->iowait_boost >>= 1;
408 if (sg_cpu->iowait_boost < IOWAIT_BOOST_MIN) {
409 sg_cpu->iowait_boost = 0;
414 sg_cpu->iowait_boost_pending = false;
417 * @util is already in capacity scale; convert iowait_boost
418 * into the same scale so we can compare.
420 boost = (sg_cpu->iowait_boost * max) >> SCHED_CAPACITY_SHIFT;
421 return max(boost, util);
424 #ifdef CONFIG_NO_HZ_COMMON
425 static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu)
427 unsigned long idle_calls = tick_nohz_get_idle_calls_cpu(sg_cpu->cpu);
428 bool ret = idle_calls == sg_cpu->saved_idle_calls;
430 sg_cpu->saved_idle_calls = idle_calls;
434 static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
435 #endif /* CONFIG_NO_HZ_COMMON */
438 * Make sugov_should_update_freq() ignore the rate limit when DL
439 * has increased the utilization.
441 static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu, struct sugov_policy *sg_policy)
443 if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_dl)
444 sg_policy->limits_changed = true;
447 static void sugov_update_single(struct update_util_data *hook, u64 time,
450 struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
451 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
452 unsigned long util, max;
456 sugov_iowait_boost(sg_cpu, time, flags);
457 sg_cpu->last_update = time;
459 ignore_dl_rate_limit(sg_cpu, sg_policy);
461 if (!sugov_should_update_freq(sg_policy, time))
464 /* Limits may have changed, don't skip frequency update */
465 busy = !sg_policy->need_freq_update && sugov_cpu_is_busy(sg_cpu);
467 util = sugov_get_util(sg_cpu);
469 util = sugov_iowait_apply(sg_cpu, time, util, max);
470 next_f = get_next_freq(sg_policy, util, max);
472 * Do not reduce the frequency if the CPU has not been idle
473 * recently, as the reduction is likely to be premature then.
475 if (busy && next_f < sg_policy->next_freq) {
476 next_f = sg_policy->next_freq;
478 /* Reset cached freq as next_freq has changed */
479 sg_policy->cached_raw_freq = 0;
483 * This code runs under rq->lock for the target CPU, so it won't run
484 * concurrently on two different CPUs for the same target and it is not
485 * necessary to acquire the lock in the fast switch case.
487 if (sg_policy->policy->fast_switch_enabled) {
488 sugov_fast_switch(sg_policy, time, next_f);
490 raw_spin_lock(&sg_policy->update_lock);
491 sugov_deferred_update(sg_policy, time, next_f);
492 raw_spin_unlock(&sg_policy->update_lock);
496 static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
498 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
499 struct cpufreq_policy *policy = sg_policy->policy;
500 unsigned long util = 0, max = 1;
503 for_each_cpu(j, policy->cpus) {
504 struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
505 unsigned long j_util, j_max;
507 j_util = sugov_get_util(j_sg_cpu);
508 j_max = j_sg_cpu->max;
509 j_util = sugov_iowait_apply(j_sg_cpu, time, j_util, j_max);
511 if (j_util * max > j_max * util) {
517 return get_next_freq(sg_policy, util, max);
521 sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int flags)
523 struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
524 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
527 raw_spin_lock(&sg_policy->update_lock);
529 sugov_iowait_boost(sg_cpu, time, flags);
530 sg_cpu->last_update = time;
532 ignore_dl_rate_limit(sg_cpu, sg_policy);
534 if (sugov_should_update_freq(sg_policy, time)) {
535 next_f = sugov_next_freq_shared(sg_cpu, time);
537 if (sg_policy->policy->fast_switch_enabled)
538 sugov_fast_switch(sg_policy, time, next_f);
540 sugov_deferred_update(sg_policy, time, next_f);
543 raw_spin_unlock(&sg_policy->update_lock);
546 static void sugov_work(struct kthread_work *work)
548 struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work);
553 * Hold sg_policy->update_lock shortly to handle the case where:
554 * incase sg_policy->next_freq is read here, and then updated by
555 * sugov_deferred_update() just before work_in_progress is set to false
556 * here, we may miss queueing the new update.
558 * Note: If a work was queued after the update_lock is released,
559 * sugov_work() will just be called again by kthread_work code; and the
560 * request will be proceed before the sugov thread sleeps.
562 raw_spin_lock_irqsave(&sg_policy->update_lock, flags);
563 freq = sg_policy->next_freq;
564 sg_policy->work_in_progress = false;
565 raw_spin_unlock_irqrestore(&sg_policy->update_lock, flags);
567 mutex_lock(&sg_policy->work_lock);
568 __cpufreq_driver_target(sg_policy->policy, freq, CPUFREQ_RELATION_L);
569 mutex_unlock(&sg_policy->work_lock);
572 static void sugov_irq_work(struct irq_work *irq_work)
574 struct sugov_policy *sg_policy;
576 sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
578 kthread_queue_work(&sg_policy->worker, &sg_policy->work);
581 /************************** sysfs interface ************************/
583 static struct sugov_tunables *global_tunables;
584 static DEFINE_MUTEX(global_tunables_lock);
586 static inline struct sugov_tunables *to_sugov_tunables(struct gov_attr_set *attr_set)
588 return container_of(attr_set, struct sugov_tunables, attr_set);
591 static ssize_t rate_limit_us_show(struct gov_attr_set *attr_set, char *buf)
593 struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
595 return sprintf(buf, "%u\n", tunables->rate_limit_us);
599 rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf, size_t count)
601 struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
602 struct sugov_policy *sg_policy;
603 unsigned int rate_limit_us;
605 if (kstrtouint(buf, 10, &rate_limit_us))
608 tunables->rate_limit_us = rate_limit_us;
610 list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook)
611 sg_policy->freq_update_delay_ns = rate_limit_us * NSEC_PER_USEC;
616 static struct governor_attr rate_limit_us = __ATTR_RW(rate_limit_us);
618 static struct attribute *sugov_attrs[] = {
622 ATTRIBUTE_GROUPS(sugov);
624 static struct kobj_type sugov_tunables_ktype = {
625 .default_groups = sugov_groups,
626 .sysfs_ops = &governor_sysfs_ops,
629 /********************** cpufreq governor interface *********************/
631 struct cpufreq_governor schedutil_gov;
633 static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy)
635 struct sugov_policy *sg_policy;
637 sg_policy = kzalloc(sizeof(*sg_policy), GFP_KERNEL);
641 sg_policy->policy = policy;
642 raw_spin_lock_init(&sg_policy->update_lock);
646 static void sugov_policy_free(struct sugov_policy *sg_policy)
651 static int sugov_kthread_create(struct sugov_policy *sg_policy)
653 struct task_struct *thread;
654 struct sched_attr attr = {
655 .size = sizeof(struct sched_attr),
656 .sched_policy = SCHED_DEADLINE,
657 .sched_flags = SCHED_FLAG_SUGOV,
661 * Fake (unused) bandwidth; workaround to "fix"
662 * priority inheritance.
664 .sched_runtime = 1000000,
665 .sched_deadline = 10000000,
666 .sched_period = 10000000,
668 struct cpufreq_policy *policy = sg_policy->policy;
671 /* kthread only required for slow path */
672 if (policy->fast_switch_enabled)
675 kthread_init_work(&sg_policy->work, sugov_work);
676 kthread_init_worker(&sg_policy->worker);
677 thread = kthread_create(kthread_worker_fn, &sg_policy->worker,
679 cpumask_first(policy->related_cpus));
680 if (IS_ERR(thread)) {
681 pr_err("failed to create sugov thread: %ld\n", PTR_ERR(thread));
682 return PTR_ERR(thread);
685 ret = sched_setattr_nocheck(thread, &attr);
687 kthread_stop(thread);
688 pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
692 sg_policy->thread = thread;
693 kthread_bind_mask(thread, policy->related_cpus);
694 init_irq_work(&sg_policy->irq_work, sugov_irq_work);
695 mutex_init(&sg_policy->work_lock);
697 wake_up_process(thread);
702 static void sugov_kthread_stop(struct sugov_policy *sg_policy)
704 /* kthread only required for slow path */
705 if (sg_policy->policy->fast_switch_enabled)
708 kthread_flush_worker(&sg_policy->worker);
709 kthread_stop(sg_policy->thread);
710 mutex_destroy(&sg_policy->work_lock);
713 static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_policy)
715 struct sugov_tunables *tunables;
717 tunables = kzalloc(sizeof(*tunables), GFP_KERNEL);
719 gov_attr_set_init(&tunables->attr_set, &sg_policy->tunables_hook);
720 if (!have_governor_per_policy())
721 global_tunables = tunables;
726 static void sugov_tunables_free(struct sugov_tunables *tunables)
728 if (!have_governor_per_policy())
729 global_tunables = NULL;
734 static int sugov_init(struct cpufreq_policy *policy)
736 struct sugov_policy *sg_policy;
737 struct sugov_tunables *tunables;
740 /* State should be equivalent to EXIT */
741 if (policy->governor_data)
744 cpufreq_enable_fast_switch(policy);
746 sg_policy = sugov_policy_alloc(policy);
749 goto disable_fast_switch;
752 ret = sugov_kthread_create(sg_policy);
756 mutex_lock(&global_tunables_lock);
758 if (global_tunables) {
759 if (WARN_ON(have_governor_per_policy())) {
763 policy->governor_data = sg_policy;
764 sg_policy->tunables = global_tunables;
766 gov_attr_set_get(&global_tunables->attr_set, &sg_policy->tunables_hook);
770 tunables = sugov_tunables_alloc(sg_policy);
776 tunables->rate_limit_us = cpufreq_policy_transition_delay_us(policy);
778 policy->governor_data = sg_policy;
779 sg_policy->tunables = tunables;
781 ret = kobject_init_and_add(&tunables->attr_set.kobj, &sugov_tunables_ktype,
782 get_governor_parent_kobj(policy), "%s",
788 mutex_unlock(&global_tunables_lock);
792 kobject_put(&tunables->attr_set.kobj);
793 policy->governor_data = NULL;
794 sugov_tunables_free(tunables);
797 sugov_kthread_stop(sg_policy);
798 mutex_unlock(&global_tunables_lock);
801 sugov_policy_free(sg_policy);
804 cpufreq_disable_fast_switch(policy);
806 pr_err("initialization failed (error %d)\n", ret);
810 static void sugov_exit(struct cpufreq_policy *policy)
812 struct sugov_policy *sg_policy = policy->governor_data;
813 struct sugov_tunables *tunables = sg_policy->tunables;
816 mutex_lock(&global_tunables_lock);
818 count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);
819 policy->governor_data = NULL;
821 sugov_tunables_free(tunables);
823 mutex_unlock(&global_tunables_lock);
825 sugov_kthread_stop(sg_policy);
826 sugov_policy_free(sg_policy);
827 cpufreq_disable_fast_switch(policy);
830 static int sugov_start(struct cpufreq_policy *policy)
832 struct sugov_policy *sg_policy = policy->governor_data;
835 sg_policy->freq_update_delay_ns = sg_policy->tunables->rate_limit_us * NSEC_PER_USEC;
836 sg_policy->last_freq_update_time = 0;
837 sg_policy->next_freq = 0;
838 sg_policy->work_in_progress = false;
839 sg_policy->limits_changed = false;
840 sg_policy->need_freq_update = false;
841 sg_policy->cached_raw_freq = 0;
843 for_each_cpu(cpu, policy->cpus) {
844 struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
846 memset(sg_cpu, 0, sizeof(*sg_cpu));
848 sg_cpu->sg_policy = sg_policy;
851 for_each_cpu(cpu, policy->cpus) {
852 struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
854 cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util,
855 policy_is_shared(policy) ?
856 sugov_update_shared :
857 sugov_update_single);
862 static void sugov_stop(struct cpufreq_policy *policy)
864 struct sugov_policy *sg_policy = policy->governor_data;
867 for_each_cpu(cpu, policy->cpus)
868 cpufreq_remove_update_util_hook(cpu);
872 if (!policy->fast_switch_enabled) {
873 irq_work_sync(&sg_policy->irq_work);
874 kthread_cancel_work_sync(&sg_policy->work);
878 static void sugov_limits(struct cpufreq_policy *policy)
880 struct sugov_policy *sg_policy = policy->governor_data;
882 if (!policy->fast_switch_enabled) {
883 mutex_lock(&sg_policy->work_lock);
884 cpufreq_policy_apply_limits(policy);
885 mutex_unlock(&sg_policy->work_lock);
888 sg_policy->limits_changed = true;
891 struct cpufreq_governor schedutil_gov = {
893 .owner = THIS_MODULE,
894 .dynamic_switching = true,
897 .start = sugov_start,
899 .limits = sugov_limits,
902 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
903 struct cpufreq_governor *cpufreq_default_governor(void)
905 return &schedutil_gov;
909 static int __init sugov_register(void)
911 return cpufreq_register_governor(&schedutil_gov);
913 fs_initcall(sugov_register);
915 #ifdef CONFIG_ENERGY_MODEL
916 extern bool sched_energy_update;
917 extern struct mutex sched_energy_mutex;
919 static void rebuild_sd_workfn(struct work_struct *work)
921 mutex_lock(&sched_energy_mutex);
922 sched_energy_update = true;
923 rebuild_sched_domains();
924 sched_energy_update = false;
925 mutex_unlock(&sched_energy_mutex);
927 static DECLARE_WORK(rebuild_sd_work, rebuild_sd_workfn);
930 * EAS shouldn't be attempted without sugov, so rebuild the sched_domains
931 * on governor changes to make sure the scheduler knows about it.
933 void sched_cpufreq_governor_change(struct cpufreq_policy *policy,
934 struct cpufreq_governor *old_gov)
936 if (old_gov == &schedutil_gov || policy->governor == &schedutil_gov) {
938 * When called from the cpufreq_register_driver() path, the
939 * cpu_hotplug_lock is already held, so use a work item to
940 * avoid nested locking in rebuild_sched_domains().
942 schedule_work(&rebuild_sd_work);