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->need_freq_update) {
106 if (sg_policy->next_freq == next_freq)
109 sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS);
112 sg_policy->next_freq = next_freq;
113 sg_policy->last_freq_update_time = time;
118 static void sugov_fast_switch(struct sugov_policy *sg_policy, u64 time,
119 unsigned int next_freq)
121 if (sugov_update_next_freq(sg_policy, time, next_freq))
122 cpufreq_driver_fast_switch(sg_policy->policy, next_freq);
125 static void sugov_deferred_update(struct sugov_policy *sg_policy, u64 time,
126 unsigned int next_freq)
128 if (!sugov_update_next_freq(sg_policy, time, next_freq))
131 if (!sg_policy->work_in_progress) {
132 sg_policy->work_in_progress = true;
133 irq_work_queue(&sg_policy->irq_work);
138 * get_next_freq - Compute a new frequency for a given cpufreq policy.
139 * @sg_policy: schedutil policy object to compute the new frequency for.
140 * @util: Current CPU utilization.
141 * @max: CPU capacity.
143 * If the utilization is frequency-invariant, choose the new frequency to be
144 * proportional to it, that is
146 * next_freq = C * max_freq * util / max
148 * Otherwise, approximate the would-be frequency-invariant utilization by
149 * util_raw * (curr_freq / max_freq) which leads to
151 * next_freq = C * curr_freq * util_raw / max
153 * Take C = 1.25 for the frequency tipping point at (util / max) = 0.8.
155 * The lowest driver-supported frequency which is equal or greater than the raw
156 * next_freq (as calculated above) is returned, subject to policy min/max and
157 * cpufreq driver limitations.
159 static unsigned int get_next_freq(struct sugov_policy *sg_policy,
160 unsigned long util, unsigned long max)
162 struct cpufreq_policy *policy = sg_policy->policy;
163 unsigned int freq = arch_scale_freq_invariant() ?
164 policy->cpuinfo.max_freq : policy->cur;
166 freq = map_util_freq(util, freq, max);
168 if (freq == sg_policy->cached_raw_freq && !sg_policy->need_freq_update)
169 return sg_policy->next_freq;
171 sg_policy->cached_raw_freq = freq;
172 return cpufreq_driver_resolve_freq(policy, freq);
176 * This function computes an effective utilization for the given CPU, to be
177 * used for frequency selection given the linear relation: f = u * f_max.
179 * The scheduler tracks the following metrics:
181 * cpu_util_{cfs,rt,dl,irq}()
184 * Where the cfs,rt and dl util numbers are tracked with the same metric and
185 * synchronized windows and are thus directly comparable.
187 * The cfs,rt,dl utilization are the running times measured with rq->clock_task
188 * which excludes things like IRQ and steal-time. These latter are then accrued
189 * in the irq utilization.
191 * The DL bandwidth number otoh is not a measured metric but a value computed
192 * based on the task model parameters and gives the minimal utilization
193 * required to meet deadlines.
195 unsigned long schedutil_cpu_util(int cpu, unsigned long util_cfs,
196 unsigned long max, enum schedutil_type type,
197 struct task_struct *p)
199 unsigned long dl_util, util, irq;
200 struct rq *rq = cpu_rq(cpu);
202 if (!uclamp_is_used() &&
203 type == FREQUENCY_UTIL && rt_rq_is_runnable(&rq->rt)) {
208 * Early check to see if IRQ/steal time saturates the CPU, can be
209 * because of inaccuracies in how we track these -- see
210 * update_irq_load_avg().
212 irq = cpu_util_irq(rq);
213 if (unlikely(irq >= max))
217 * Because the time spend on RT/DL tasks is visible as 'lost' time to
218 * CFS tasks and we use the same metric to track the effective
219 * utilization (PELT windows are synchronized) we can directly add them
220 * to obtain the CPU's actual utilization.
222 * CFS and RT utilization can be boosted or capped, depending on
223 * utilization clamp constraints requested by currently RUNNABLE
225 * When there are no CFS RUNNABLE tasks, clamps are released and
226 * frequency will be gracefully reduced with the utilization decay.
228 util = util_cfs + cpu_util_rt(rq);
229 if (type == FREQUENCY_UTIL)
230 util = uclamp_rq_util_with(rq, util, p);
232 dl_util = cpu_util_dl(rq);
235 * For frequency selection we do not make cpu_util_dl() a permanent part
236 * of this sum because we want to use cpu_bw_dl() later on, but we need
237 * to check if the CFS+RT+DL sum is saturated (ie. no idle time) such
238 * that we select f_max when there is no idle time.
240 * NOTE: numerical errors or stop class might cause us to not quite hit
241 * saturation when we should -- something for later.
243 if (util + dl_util >= max)
247 * OTOH, for energy computation we need the estimated running time, so
248 * include util_dl and ignore dl_bw.
250 if (type == ENERGY_UTIL)
254 * There is still idle time; further improve the number by using the
255 * irq metric. Because IRQ/steal time is hidden from the task clock we
256 * need to scale the task numbers:
259 * U' = irq + --------- * U
262 util = scale_irq_capacity(util, irq, max);
266 * Bandwidth required by DEADLINE must always be granted while, for
267 * FAIR and RT, we use blocked utilization of IDLE CPUs as a mechanism
268 * to gracefully reduce the frequency when no tasks show up for longer
271 * Ideally we would like to set bw_dl as min/guaranteed freq and util +
272 * bw_dl as requested freq. However, cpufreq is not yet ready for such
273 * an interface. So, we only do the latter for now.
275 if (type == FREQUENCY_UTIL)
276 util += cpu_bw_dl(rq);
278 return min(max, util);
281 static unsigned long sugov_get_util(struct sugov_cpu *sg_cpu)
283 struct rq *rq = cpu_rq(sg_cpu->cpu);
284 unsigned long util = cpu_util_cfs(rq);
285 unsigned long max = arch_scale_cpu_capacity(sg_cpu->cpu);
288 sg_cpu->bw_dl = cpu_bw_dl(rq);
290 return schedutil_cpu_util(sg_cpu->cpu, util, max, FREQUENCY_UTIL, NULL);
294 * sugov_iowait_reset() - Reset the IO boost status of a CPU.
295 * @sg_cpu: the sugov data for the CPU to boost
296 * @time: the update time from the caller
297 * @set_iowait_boost: true if an IO boost has been requested
299 * The IO wait boost of a task is disabled after a tick since the last update
300 * of a CPU. If a new IO wait boost is requested after more then a tick, then
301 * we enable the boost starting from IOWAIT_BOOST_MIN, which improves energy
302 * efficiency by ignoring sporadic wakeups from IO.
304 static bool sugov_iowait_reset(struct sugov_cpu *sg_cpu, u64 time,
305 bool set_iowait_boost)
307 s64 delta_ns = time - sg_cpu->last_update;
309 /* Reset boost only if a tick has elapsed since last request */
310 if (delta_ns <= TICK_NSEC)
313 sg_cpu->iowait_boost = set_iowait_boost ? IOWAIT_BOOST_MIN : 0;
314 sg_cpu->iowait_boost_pending = set_iowait_boost;
320 * sugov_iowait_boost() - Updates the IO boost status of a CPU.
321 * @sg_cpu: the sugov data for the CPU to boost
322 * @time: the update time from the caller
323 * @flags: SCHED_CPUFREQ_IOWAIT if the task is waking up after an IO wait
325 * Each time a task wakes up after an IO operation, the CPU utilization can be
326 * boosted to a certain utilization which doubles at each "frequent and
327 * successive" wakeup from IO, ranging from IOWAIT_BOOST_MIN to the utilization
328 * of the maximum OPP.
330 * To keep doubling, an IO boost has to be requested at least once per tick,
331 * otherwise we restart from the utilization of the minimum OPP.
333 static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
336 bool set_iowait_boost = flags & SCHED_CPUFREQ_IOWAIT;
338 /* Reset boost if the CPU appears to have been idle enough */
339 if (sg_cpu->iowait_boost &&
340 sugov_iowait_reset(sg_cpu, time, set_iowait_boost))
343 /* Boost only tasks waking up after IO */
344 if (!set_iowait_boost)
347 /* Ensure boost doubles only one time at each request */
348 if (sg_cpu->iowait_boost_pending)
350 sg_cpu->iowait_boost_pending = true;
352 /* Double the boost at each request */
353 if (sg_cpu->iowait_boost) {
354 sg_cpu->iowait_boost =
355 min_t(unsigned int, sg_cpu->iowait_boost << 1, SCHED_CAPACITY_SCALE);
359 /* First wakeup after IO: start with minimum boost */
360 sg_cpu->iowait_boost = IOWAIT_BOOST_MIN;
364 * sugov_iowait_apply() - Apply the IO boost to a CPU.
365 * @sg_cpu: the sugov data for the cpu to boost
366 * @time: the update time from the caller
367 * @util: the utilization to (eventually) boost
368 * @max: the maximum value the utilization can be boosted to
370 * A CPU running a task which woken up after an IO operation can have its
371 * utilization boosted to speed up the completion of those IO operations.
372 * The IO boost value is increased each time a task wakes up from IO, in
373 * sugov_iowait_apply(), and it's instead decreased by this function,
374 * each time an increase has not been requested (!iowait_boost_pending).
376 * A CPU which also appears to have been idle for at least one tick has also
377 * its IO boost utilization reset.
379 * This mechanism is designed to boost high frequently IO waiting tasks, while
380 * being more conservative on tasks which does sporadic IO operations.
382 static unsigned long sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time,
383 unsigned long util, unsigned long max)
387 /* No boost currently required */
388 if (!sg_cpu->iowait_boost)
391 /* Reset boost if the CPU appears to have been idle enough */
392 if (sugov_iowait_reset(sg_cpu, time, false))
395 if (!sg_cpu->iowait_boost_pending) {
397 * No boost pending; reduce the boost value.
399 sg_cpu->iowait_boost >>= 1;
400 if (sg_cpu->iowait_boost < IOWAIT_BOOST_MIN) {
401 sg_cpu->iowait_boost = 0;
406 sg_cpu->iowait_boost_pending = false;
409 * @util is already in capacity scale; convert iowait_boost
410 * into the same scale so we can compare.
412 boost = (sg_cpu->iowait_boost * max) >> SCHED_CAPACITY_SHIFT;
413 return max(boost, util);
416 #ifdef CONFIG_NO_HZ_COMMON
417 static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu)
419 unsigned long idle_calls = tick_nohz_get_idle_calls_cpu(sg_cpu->cpu);
420 bool ret = idle_calls == sg_cpu->saved_idle_calls;
422 sg_cpu->saved_idle_calls = idle_calls;
426 static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
427 #endif /* CONFIG_NO_HZ_COMMON */
430 * Make sugov_should_update_freq() ignore the rate limit when DL
431 * has increased the utilization.
433 static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu, struct sugov_policy *sg_policy)
435 if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_dl)
436 sg_policy->limits_changed = true;
439 static void sugov_update_single(struct update_util_data *hook, u64 time,
442 struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
443 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
444 unsigned long util, max;
446 unsigned int cached_freq = sg_policy->cached_raw_freq;
448 sugov_iowait_boost(sg_cpu, time, flags);
449 sg_cpu->last_update = time;
451 ignore_dl_rate_limit(sg_cpu, sg_policy);
453 if (!sugov_should_update_freq(sg_policy, time))
456 util = sugov_get_util(sg_cpu);
458 util = sugov_iowait_apply(sg_cpu, time, util, max);
459 next_f = get_next_freq(sg_policy, util, max);
461 * Do not reduce the frequency if the CPU has not been idle
462 * recently, as the reduction is likely to be premature then.
464 if (sugov_cpu_is_busy(sg_cpu) && next_f < sg_policy->next_freq) {
465 next_f = sg_policy->next_freq;
467 /* Restore cached freq as next_freq has changed */
468 sg_policy->cached_raw_freq = cached_freq;
472 * This code runs under rq->lock for the target CPU, so it won't run
473 * concurrently on two different CPUs for the same target and it is not
474 * necessary to acquire the lock in the fast switch case.
476 if (sg_policy->policy->fast_switch_enabled) {
477 sugov_fast_switch(sg_policy, time, next_f);
479 raw_spin_lock(&sg_policy->update_lock);
480 sugov_deferred_update(sg_policy, time, next_f);
481 raw_spin_unlock(&sg_policy->update_lock);
485 static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
487 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
488 struct cpufreq_policy *policy = sg_policy->policy;
489 unsigned long util = 0, max = 1;
492 for_each_cpu(j, policy->cpus) {
493 struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
494 unsigned long j_util, j_max;
496 j_util = sugov_get_util(j_sg_cpu);
497 j_max = j_sg_cpu->max;
498 j_util = sugov_iowait_apply(j_sg_cpu, time, j_util, j_max);
500 if (j_util * max > j_max * util) {
506 return get_next_freq(sg_policy, util, max);
510 sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int flags)
512 struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
513 struct sugov_policy *sg_policy = sg_cpu->sg_policy;
516 raw_spin_lock(&sg_policy->update_lock);
518 sugov_iowait_boost(sg_cpu, time, flags);
519 sg_cpu->last_update = time;
521 ignore_dl_rate_limit(sg_cpu, sg_policy);
523 if (sugov_should_update_freq(sg_policy, time)) {
524 next_f = sugov_next_freq_shared(sg_cpu, time);
526 if (sg_policy->policy->fast_switch_enabled)
527 sugov_fast_switch(sg_policy, time, next_f);
529 sugov_deferred_update(sg_policy, time, next_f);
532 raw_spin_unlock(&sg_policy->update_lock);
535 static void sugov_work(struct kthread_work *work)
537 struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work);
542 * Hold sg_policy->update_lock shortly to handle the case where:
543 * incase sg_policy->next_freq is read here, and then updated by
544 * sugov_deferred_update() just before work_in_progress is set to false
545 * here, we may miss queueing the new update.
547 * Note: If a work was queued after the update_lock is released,
548 * sugov_work() will just be called again by kthread_work code; and the
549 * request will be proceed before the sugov thread sleeps.
551 raw_spin_lock_irqsave(&sg_policy->update_lock, flags);
552 freq = sg_policy->next_freq;
553 sg_policy->work_in_progress = false;
554 raw_spin_unlock_irqrestore(&sg_policy->update_lock, flags);
556 mutex_lock(&sg_policy->work_lock);
557 __cpufreq_driver_target(sg_policy->policy, freq, CPUFREQ_RELATION_L);
558 mutex_unlock(&sg_policy->work_lock);
561 static void sugov_irq_work(struct irq_work *irq_work)
563 struct sugov_policy *sg_policy;
565 sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
567 kthread_queue_work(&sg_policy->worker, &sg_policy->work);
570 /************************** sysfs interface ************************/
572 static struct sugov_tunables *global_tunables;
573 static DEFINE_MUTEX(global_tunables_lock);
575 static inline struct sugov_tunables *to_sugov_tunables(struct gov_attr_set *attr_set)
577 return container_of(attr_set, struct sugov_tunables, attr_set);
580 static ssize_t rate_limit_us_show(struct gov_attr_set *attr_set, char *buf)
582 struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
584 return sprintf(buf, "%u\n", tunables->rate_limit_us);
588 rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf, size_t count)
590 struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
591 struct sugov_policy *sg_policy;
592 unsigned int rate_limit_us;
594 if (kstrtouint(buf, 10, &rate_limit_us))
597 tunables->rate_limit_us = rate_limit_us;
599 list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook)
600 sg_policy->freq_update_delay_ns = rate_limit_us * NSEC_PER_USEC;
605 static struct governor_attr rate_limit_us = __ATTR_RW(rate_limit_us);
607 static struct attribute *sugov_attrs[] = {
611 ATTRIBUTE_GROUPS(sugov);
613 static void sugov_tunables_free(struct kobject *kobj)
615 struct gov_attr_set *attr_set = container_of(kobj, struct gov_attr_set, kobj);
617 kfree(to_sugov_tunables(attr_set));
620 static struct kobj_type sugov_tunables_ktype = {
621 .default_groups = sugov_groups,
622 .sysfs_ops = &governor_sysfs_ops,
623 .release = &sugov_tunables_free,
626 /********************** cpufreq governor interface *********************/
628 struct cpufreq_governor schedutil_gov;
630 static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy)
632 struct sugov_policy *sg_policy;
634 sg_policy = kzalloc(sizeof(*sg_policy), GFP_KERNEL);
638 sg_policy->policy = policy;
639 raw_spin_lock_init(&sg_policy->update_lock);
643 static void sugov_policy_free(struct sugov_policy *sg_policy)
648 static int sugov_kthread_create(struct sugov_policy *sg_policy)
650 struct task_struct *thread;
651 struct sched_attr attr = {
652 .size = sizeof(struct sched_attr),
653 .sched_policy = SCHED_DEADLINE,
654 .sched_flags = SCHED_FLAG_SUGOV,
658 * Fake (unused) bandwidth; workaround to "fix"
659 * priority inheritance.
661 .sched_runtime = 1000000,
662 .sched_deadline = 10000000,
663 .sched_period = 10000000,
665 struct cpufreq_policy *policy = sg_policy->policy;
668 /* kthread only required for slow path */
669 if (policy->fast_switch_enabled)
672 kthread_init_work(&sg_policy->work, sugov_work);
673 kthread_init_worker(&sg_policy->worker);
674 thread = kthread_create(kthread_worker_fn, &sg_policy->worker,
676 cpumask_first(policy->related_cpus));
677 if (IS_ERR(thread)) {
678 pr_err("failed to create sugov thread: %ld\n", PTR_ERR(thread));
679 return PTR_ERR(thread);
682 ret = sched_setattr_nocheck(thread, &attr);
684 kthread_stop(thread);
685 pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
689 sg_policy->thread = thread;
690 kthread_bind_mask(thread, policy->related_cpus);
691 init_irq_work(&sg_policy->irq_work, sugov_irq_work);
692 mutex_init(&sg_policy->work_lock);
694 wake_up_process(thread);
699 static void sugov_kthread_stop(struct sugov_policy *sg_policy)
701 /* kthread only required for slow path */
702 if (sg_policy->policy->fast_switch_enabled)
705 kthread_flush_worker(&sg_policy->worker);
706 kthread_stop(sg_policy->thread);
707 mutex_destroy(&sg_policy->work_lock);
710 static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_policy)
712 struct sugov_tunables *tunables;
714 tunables = kzalloc(sizeof(*tunables), GFP_KERNEL);
716 gov_attr_set_init(&tunables->attr_set, &sg_policy->tunables_hook);
717 if (!have_governor_per_policy())
718 global_tunables = tunables;
723 static void sugov_clear_global_tunables(void)
725 if (!have_governor_per_policy())
726 global_tunables = NULL;
729 static int sugov_init(struct cpufreq_policy *policy)
731 struct sugov_policy *sg_policy;
732 struct sugov_tunables *tunables;
735 /* State should be equivalent to EXIT */
736 if (policy->governor_data)
739 cpufreq_enable_fast_switch(policy);
741 sg_policy = sugov_policy_alloc(policy);
744 goto disable_fast_switch;
747 ret = sugov_kthread_create(sg_policy);
751 mutex_lock(&global_tunables_lock);
753 if (global_tunables) {
754 if (WARN_ON(have_governor_per_policy())) {
758 policy->governor_data = sg_policy;
759 sg_policy->tunables = global_tunables;
761 gov_attr_set_get(&global_tunables->attr_set, &sg_policy->tunables_hook);
765 tunables = sugov_tunables_alloc(sg_policy);
771 tunables->rate_limit_us = cpufreq_policy_transition_delay_us(policy);
773 policy->governor_data = sg_policy;
774 sg_policy->tunables = tunables;
776 ret = kobject_init_and_add(&tunables->attr_set.kobj, &sugov_tunables_ktype,
777 get_governor_parent_kobj(policy), "%s",
783 mutex_unlock(&global_tunables_lock);
787 kobject_put(&tunables->attr_set.kobj);
788 policy->governor_data = NULL;
789 sugov_clear_global_tunables();
792 sugov_kthread_stop(sg_policy);
793 mutex_unlock(&global_tunables_lock);
796 sugov_policy_free(sg_policy);
799 cpufreq_disable_fast_switch(policy);
801 pr_err("initialization failed (error %d)\n", ret);
805 static void sugov_exit(struct cpufreq_policy *policy)
807 struct sugov_policy *sg_policy = policy->governor_data;
808 struct sugov_tunables *tunables = sg_policy->tunables;
811 mutex_lock(&global_tunables_lock);
813 count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);
814 policy->governor_data = NULL;
816 sugov_clear_global_tunables();
818 mutex_unlock(&global_tunables_lock);
820 sugov_kthread_stop(sg_policy);
821 sugov_policy_free(sg_policy);
822 cpufreq_disable_fast_switch(policy);
825 static int sugov_start(struct cpufreq_policy *policy)
827 struct sugov_policy *sg_policy = policy->governor_data;
830 sg_policy->freq_update_delay_ns = sg_policy->tunables->rate_limit_us * NSEC_PER_USEC;
831 sg_policy->last_freq_update_time = 0;
832 sg_policy->next_freq = 0;
833 sg_policy->work_in_progress = false;
834 sg_policy->limits_changed = false;
835 sg_policy->cached_raw_freq = 0;
837 sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS);
839 for_each_cpu(cpu, policy->cpus) {
840 struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
842 memset(sg_cpu, 0, sizeof(*sg_cpu));
844 sg_cpu->sg_policy = sg_policy;
847 for_each_cpu(cpu, policy->cpus) {
848 struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
850 cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util,
851 policy_is_shared(policy) ?
852 sugov_update_shared :
853 sugov_update_single);
858 static void sugov_stop(struct cpufreq_policy *policy)
860 struct sugov_policy *sg_policy = policy->governor_data;
863 for_each_cpu(cpu, policy->cpus)
864 cpufreq_remove_update_util_hook(cpu);
868 if (!policy->fast_switch_enabled) {
869 irq_work_sync(&sg_policy->irq_work);
870 kthread_cancel_work_sync(&sg_policy->work);
874 static void sugov_limits(struct cpufreq_policy *policy)
876 struct sugov_policy *sg_policy = policy->governor_data;
878 if (!policy->fast_switch_enabled) {
879 mutex_lock(&sg_policy->work_lock);
880 cpufreq_policy_apply_limits(policy);
881 mutex_unlock(&sg_policy->work_lock);
884 sg_policy->limits_changed = true;
887 struct cpufreq_governor schedutil_gov = {
889 .owner = THIS_MODULE,
890 .flags = CPUFREQ_GOV_DYNAMIC_SWITCHING,
893 .start = sugov_start,
895 .limits = sugov_limits,
898 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
899 struct cpufreq_governor *cpufreq_default_governor(void)
901 return &schedutil_gov;
905 cpufreq_governor_init(schedutil_gov);
907 #ifdef CONFIG_ENERGY_MODEL
908 extern bool sched_energy_update;
909 extern struct mutex sched_energy_mutex;
911 static void rebuild_sd_workfn(struct work_struct *work)
913 mutex_lock(&sched_energy_mutex);
914 sched_energy_update = true;
915 rebuild_sched_domains();
916 sched_energy_update = false;
917 mutex_unlock(&sched_energy_mutex);
919 static DECLARE_WORK(rebuild_sd_work, rebuild_sd_workfn);
922 * EAS shouldn't be attempted without sugov, so rebuild the sched_domains
923 * on governor changes to make sure the scheduler knows about it.
925 void sched_cpufreq_governor_change(struct cpufreq_policy *policy,
926 struct cpufreq_governor *old_gov)
928 if (old_gov == &schedutil_gov || policy->governor == &schedutil_gov) {
930 * When called from the cpufreq_register_driver() path, the
931 * cpu_hotplug_lock is already held, so use a work item to
932 * avoid nested locking in rebuild_sched_domains().
934 schedule_work(&rebuild_sd_work);