// SPDX-License-Identifier: GPL-2.0 /* * CPUFreq governor based on scheduler-provided CPU utilization data. * * Copyright (C) 2016, Intel Corporation * Author: Rafael J. Wysocki */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include "sched.h" #include #include #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; 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 util; 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->need_freq_update) sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS); else 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) { if (sugov_update_next_freq(sg_policy, time, next_freq)) cpufreq_driver_fast_switch(sg_policy->policy, next_freq); } 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->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 (!uclamp_is_used() && 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_rq_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 void sugov_get_util(struct sugov_cpu *sg_cpu) { struct rq *rq = cpu_rq(sg_cpu->cpu); unsigned long max = arch_scale_cpu_capacity(sg_cpu->cpu); sg_cpu->max = max; sg_cpu->bw_dl = cpu_bw_dl(rq); sg_cpu->util = schedutil_cpu_util(sg_cpu->cpu, cpu_util_cfs(rq), 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 * * 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 void sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time) { unsigned long boost; /* No boost currently required */ if (!sg_cpu->iowait_boost) return; /* Reset boost if the CPU appears to have been idle enough */ if (sugov_iowait_reset(sg_cpu, time, false)) return; 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; } } sg_cpu->iowait_boost_pending = false; /* * sg_cpu->util is already in capacity scale; convert iowait_boost * into the same scale so we can compare. */ boost = (sg_cpu->iowait_boost * sg_cpu->max) >> SCHED_CAPACITY_SHIFT; if (sg_cpu->util < boost) sg_cpu->util = boost; } #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) { if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_dl) sg_cpu->sg_policy->limits_changed = true; } static inline bool sugov_update_single_common(struct sugov_cpu *sg_cpu, u64 time, unsigned int flags) { sugov_iowait_boost(sg_cpu, time, flags); sg_cpu->last_update = time; ignore_dl_rate_limit(sg_cpu); if (!sugov_should_update_freq(sg_cpu->sg_policy, time)) return false; sugov_get_util(sg_cpu); sugov_iowait_apply(sg_cpu, time); return true; } static void sugov_update_single_freq(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 cached_freq = sg_policy->cached_raw_freq; unsigned int next_f; if (!sugov_update_single_common(sg_cpu, time, flags)) return; next_f = get_next_freq(sg_policy, sg_cpu->util, sg_cpu->max); /* * Do not reduce the frequency if the CPU has not been idle * recently, as the reduction is likely to be premature then. */ if (sugov_cpu_is_busy(sg_cpu) && next_f < sg_policy->next_freq) { next_f = sg_policy->next_freq; /* Restore cached freq as next_freq has changed */ sg_policy->cached_raw_freq = cached_freq; } /* * 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 void sugov_update_single_perf(struct update_util_data *hook, u64 time, unsigned int flags) { struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util); unsigned long prev_util = sg_cpu->util; /* * Fall back to the "frequency" path if frequency invariance is not * supported, because the direct mapping between the utilization and * the performance levels depends on the frequency invariance. */ if (!arch_scale_freq_invariant()) { sugov_update_single_freq(hook, time, flags); return; } if (!sugov_update_single_common(sg_cpu, time, flags)) return; /* * Do not reduce the target performance level if the CPU has not been * idle recently, as the reduction is likely to be premature then. */ if (sugov_cpu_is_busy(sg_cpu) && sg_cpu->util < prev_util) sg_cpu->util = prev_util; cpufreq_driver_adjust_perf(sg_cpu->cpu, map_util_perf(sg_cpu->bw_dl), map_util_perf(sg_cpu->util), sg_cpu->max); sg_cpu->sg_policy->last_freq_update_time = time; } 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; sugov_get_util(j_sg_cpu); sugov_iowait_apply(j_sg_cpu, time); j_util = j_sg_cpu->util; j_max = j_sg_cpu->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); 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; void (*uu)(struct update_util_data *data, u64 time, unsigned int flags); 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->cached_raw_freq = 0; sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS); 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; } if (policy_is_shared(policy)) uu = sugov_update_shared; else if (policy->fast_switch_enabled && cpufreq_driver_has_adjust_perf()) uu = sugov_update_single_perf; else uu = sugov_update_single_freq; 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, uu); } 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, .flags = CPUFREQ_GOV_DYNAMIC_SWITCHING, .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 cpufreq_governor_init(schedutil_gov); #ifdef CONFIG_ENERGY_MODEL static void rebuild_sd_workfn(struct work_struct *work) { rebuild_sched_domains_energy(); } 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