LordMixy
commented
1 week ago // SPDX-License-Identifier: GPL-2.0
/*
* CPUFreq governor based on scheduler-provided CPU utilization data.
*
* Copyright (C) 2016, Intel Corporation
* Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
*/
#define 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_min;
/* 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_deferred_update(struct sugov_policy *sg_policy)
{
if (!sg_policy->work_in_progress) {
sg_policy->work_in_progress = true;
irq_work_queue(&sg_policy->irq_work);
}
}
/**
* get_capacity_ref_freq - get the reference frequency that has been used to
* correlate frequency and compute capacity for a given cpufreq policy. We use
* the CPU managing it for the arch_scale_freq_ref() call in the function.
* @policy: the cpufreq policy of the CPU in question.
*
* Return: the reference CPU frequency to compute a capacity.
*/
static __always_inline
unsigned long get_capacity_ref_freq(struct cpufreq_policy *policy)
{
unsigned int freq = arch_scale_freq_ref(policy->cpu);
if (freq)
return freq;
if (arch_scale_freq_invariant())
return policy->cpuinfo.max_freq;
/*
* Apply a 25% margin so that we select a higher frequency than
* the current one before the CPU is fully busy:
*/
return policy->cur + (policy->cur >> 2);
}
/**
* 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;
freq = get_capacity_ref_freq(policy);
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);
}
unsigned long sugov_effective_cpu_perf(int cpu, unsigned long actual,
unsigned long min,
unsigned long max)
{
/* Add dvfs headroom to actual utilization */
actual = map_util_perf(actual);
/* Actually we don't need to target the max performance */
if (actual < max)
max = actual;
/*
* Ensure at least minimum performance while providing more compute
* capacity when possible.
*/
return max(min, max);
}
static void sugov_get_util(struct sugov_cpu *sg_cpu, unsigned long boost)
{
unsigned long min, max, util = scx_cpuperf_target(sg_cpu->cpu);
if (!scx_switched_all())
util += cpu_util_cfs_boost(sg_cpu->cpu);
util = effective_cpu_util(sg_cpu->cpu, util, &min, &max);
util = max(util, boost);
sg_cpu->bw_min = min;
sg_cpu->util = sugov_effective_cpu_perf(sg_cpu->cpu, util, min, max);
}
/**
* 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
* @max_cap: the max CPU capacity
*
* A CPU running a task which woken up after an IO operation can have its
* utilization boosted to speed up the completion of those IO operations.
* The IO boost value is increased each time a task wakes up from IO, in
* sugov_iowait_apply(), and it's instead decreased by this function,
* each time an increase has not been requested (!iowait_boost_pending).
*
* A CPU which also appears to have been idle for at least one tick has also
* its IO boost utilization reset.
*
* This mechanism is designed to boost high frequently IO waiting tasks, while
* being more conservative on tasks which does sporadic IO operations.
*/
static unsigned long sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time,
unsigned long max_cap)
{
/* No boost currently required */
if (!sg_cpu->iowait_boost)
return 0;
/* Reset boost if the CPU appears to have been idle enough */
if (sugov_iowait_reset(sg_cpu, time, false))
return 0;
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 0;
}
}
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.
*/
return (sg_cpu->iowait_boost * max_cap) >> SCHED_CAPACITY_SHIFT;
}
#ifdef CONFIG_NO_HZ_COMMON
static bool sugov_hold_freq(struct sugov_cpu *sg_cpu)
{
unsigned long idle_calls;
bool ret;
/*
* The heuristics in this function is for the fair class. For SCX, the
* performance target comes directly from the BPF scheduler. Let's just
* follow it.
*/
if (scx_switched_all())
return false;
/* if capped by uclamp_max, always update to be in compliance */
if (uclamp_rq_is_capped(cpu_rq(sg_cpu->cpu)))
return false;
/*
* Maintain the frequency if the CPU has not been idle recently, as
* reduction is likely to be premature.
*/
idle_calls = tick_nohz_get_idle_calls_cpu(sg_cpu->cpu);
ret = idle_calls == sg_cpu->saved_idle_calls;
sg_cpu->saved_idle_calls = idle_calls;
return ret;
}
#else
static inline bool sugov_hold_freq(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_min)
sg_cpu->sg_policy->limits_changed = true;
}
static inline bool sugov_update_single_common(struct sugov_cpu *sg_cpu,
u64 time, unsigned long max_cap,
unsigned int flags)
{
unsigned long boost;
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;
boost = sugov_iowait_apply(sg_cpu, time, max_cap);
sugov_get_util(sg_cpu, boost);
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 long max_cap;
unsigned int next_f;
max_cap = arch_scale_cpu_capacity(sg_cpu->cpu);
if (!sugov_update_single_common(sg_cpu, time, max_cap, flags))
return;
next_f = get_next_freq(sg_policy, sg_cpu->util, max_cap);
if (sugov_hold_freq(sg_cpu) && next_f < sg_policy->next_freq &&
!sg_policy->need_freq_update) {
next_f = sg_policy->next_freq;
/* Restore cached freq as next_freq has changed */
sg_policy->cached_raw_freq = cached_freq;
}
if (!sugov_update_next_freq(sg_policy, time, next_f))
return;
/*
* 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) {
cpufreq_driver_fast_switch(sg_policy->policy, next_f);
} else {
raw_spin_lock(&sg_policy->update_lock);
sugov_deferred_update(sg_policy);
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;
unsigned long max_cap;
/*
* 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;
}
max_cap = arch_scale_cpu_capacity(sg_cpu->cpu);
if (!sugov_update_single_common(sg_cpu, time, max_cap, flags))
return;
if (sugov_hold_freq(sg_cpu) && sg_cpu->util < prev_util)
sg_cpu->util = prev_util;
cpufreq_driver_adjust_perf(sg_cpu->cpu, sg_cpu->bw_min,
sg_cpu->util, max_cap);
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_cap;
unsigned int j;
max_cap = arch_scale_cpu_capacity(sg_cpu->cpu);
for_each_cpu(j, policy->cpus) {
struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
unsigned long boost;
boost = sugov_iowait_apply(j_sg_cpu, time, max_cap);
sugov_get_util(j_sg_cpu, boost);
util = max(j_sg_cpu->util, util);
}
return get_next_freq(sg_policy, util, max_cap);
}
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 (!sugov_update_next_freq(sg_policy, time, next_f))
goto unlock;
if (sg_policy->policy->fast_switch_enabled)
cpufreq_driver_fast_switch(sg_policy->policy, next_f);
else
sugov_deferred_update(sg_policy);
}
unlock:
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:
* in case 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 void sugov_tunables_free(struct kobject *kobj)
{
struct gov_attr_set *attr_set = to_gov_attr_set(kobj);
kfree(to_sugov_tunables(attr_set));
}
static const struct kobj_type sugov_tunables_ktype = {
.default_groups = sugov_groups,
.sysfs_ops = &governor_sysfs_ops,
.release = &sugov_tunables_free,
};
/********************** cpufreq governor interface *********************/
#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.
*/
static void sugov_eas_rebuild_sd(void)
{
/*
* 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);
}
#else
static inline void sugov_eas_rebuild_sd(void) { };
#endif
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 = NSEC_PER_MSEC,
.sched_deadline = 10 * NSEC_PER_MSEC,
.sched_period = 10 * NSEC_PER_MSEC,
};
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_clear_global_tunables(void)
{
if (!have_governor_per_policy())
global_tunables = NULL;
}
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;
sugov_eas_rebuild_sd();
out:
mutex_unlock(&global_tunables_lock);
return 0;
fail:
kobject_put(&tunables->attr_set.kobj);
policy->governor_data = NULL;
sugov_clear_global_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_clear_global_tunables();
mutex_unlock(&global_tunables_lock);
sugov_kthread_stop(sg_policy);
sugov_policy_free(sg_policy);
cpufreq_disable_fast_switch(policy);
sugov_eas_rebuild_sd();
}
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);
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);
memset(sg_cpu, 0, sizeof(*sg_cpu));
sg_cpu->cpu = cpu;
sg_cpu->sg_policy = sg_policy;
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);
Acceptance criteria: create the executable and launch the game when doubleclicking it