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authorRafael J. Wysocki2016-04-28 15:19:31 +0200
committerRafael J. Wysocki2016-04-28 15:19:31 +0200
commit29c5e7b2bc875c4ad5d3fd9e3c4ed2702e705bba (patch)
treed3586c1f6a89150fcf24702b24aa21dcd7745f7b /kernel/sched
parent6f707daa3833761110a03478cba5cc4b708ec77d (diff)
parentb4f4b4b37133340befa354fbaa54d8e84ea86103 (diff)
Merge back earlier cpufreq material for v4.7.
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/Makefile1
-rw-r--r--kernel/sched/cpufreq.c48
-rw-r--r--kernel/sched/cpufreq_schedutil.c530
-rw-r--r--kernel/sched/sched.h8
4 files changed, 576 insertions, 11 deletions
diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
index 414d9c16da42..5e59b832ae2b 100644
--- a/kernel/sched/Makefile
+++ b/kernel/sched/Makefile
@@ -24,3 +24,4 @@ obj-$(CONFIG_SCHEDSTATS) += stats.o
obj-$(CONFIG_SCHED_DEBUG) += debug.o
obj-$(CONFIG_CGROUP_CPUACCT) += cpuacct.o
obj-$(CONFIG_CPU_FREQ) += cpufreq.o
+obj-$(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) += cpufreq_schedutil.o
diff --git a/kernel/sched/cpufreq.c b/kernel/sched/cpufreq.c
index 928c4ba32f68..1141954e73b4 100644
--- a/kernel/sched/cpufreq.c
+++ b/kernel/sched/cpufreq.c
@@ -14,24 +14,50 @@
DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data);
/**
- * cpufreq_set_update_util_data - Populate the CPU's update_util_data pointer.
+ * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer.
* @cpu: The CPU to set the pointer for.
* @data: New pointer value.
+ * @func: Callback function to set for the CPU.
*
- * Set and publish the update_util_data pointer for the given CPU. That pointer
- * points to a struct update_util_data object containing a callback function
- * to call from cpufreq_update_util(). That function will be called from an RCU
- * read-side critical section, so it must not sleep.
+ * Set and publish the update_util_data pointer for the given CPU.
*
- * Callers must use RCU-sched callbacks to free any memory that might be
- * accessed via the old update_util_data pointer or invoke synchronize_sched()
- * right after this function to avoid use-after-free.
+ * The update_util_data pointer of @cpu is set to @data and the callback
+ * function pointer in the target struct update_util_data is set to @func.
+ * That function will be called by cpufreq_update_util() from RCU-sched
+ * read-side critical sections, so it must not sleep. @data will always be
+ * passed to it as the first argument which allows the function to get to the
+ * target update_util_data structure and its container.
+ *
+ * The update_util_data pointer of @cpu must be NULL when this function is
+ * called or it will WARN() and return with no effect.
*/
-void cpufreq_set_update_util_data(int cpu, struct update_util_data *data)
+void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data,
+ void (*func)(struct update_util_data *data, u64 time,
+ unsigned long util, unsigned long max))
{
- if (WARN_ON(data && !data->func))
+ if (WARN_ON(!data || !func))
return;
+ if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu)))
+ return;
+
+ data->func = func;
rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data);
}
-EXPORT_SYMBOL_GPL(cpufreq_set_update_util_data);
+EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook);
+
+/**
+ * cpufreq_remove_update_util_hook - Clear the CPU's update_util_data pointer.
+ * @cpu: The CPU to clear the pointer for.
+ *
+ * Clear the update_util_data pointer for the given CPU.
+ *
+ * Callers must use RCU-sched callbacks to free any memory that might be
+ * accessed via the old update_util_data pointer or invoke synchronize_sched()
+ * right after this function to avoid use-after-free.
+ */
+void cpufreq_remove_update_util_hook(int cpu)
+{
+ rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL);
+}
+EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook);
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
new file mode 100644
index 000000000000..154ae3a51e86
--- /dev/null
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -0,0 +1,530 @@
+/*
+ * CPUFreq governor based on scheduler-provided CPU utilization data.
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/cpufreq.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <trace/events/power.h>
+
+#include "sched.h"
+
+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; /* For shared policies */
+ u64 last_freq_update_time;
+ s64 freq_update_delay_ns;
+ unsigned int next_freq;
+
+ /* The next fields are only needed if fast switch cannot be used. */
+ struct irq_work irq_work;
+ struct work_struct work;
+ struct mutex work_lock;
+ bool work_in_progress;
+
+ bool need_freq_update;
+};
+
+struct sugov_cpu {
+ struct update_util_data update_util;
+ struct sugov_policy *sg_policy;
+
+ /* The fields below are only needed when sharing a policy. */
+ unsigned long util;
+ unsigned long max;
+ u64 last_update;
+};
+
+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;
+
+ if (sg_policy->work_in_progress)
+ return false;
+
+ if (unlikely(sg_policy->need_freq_update)) {
+ sg_policy->need_freq_update = false;
+ /*
+ * This happens when limits change, so forget the previous
+ * next_freq value and force an update.
+ */
+ sg_policy->next_freq = UINT_MAX;
+ return true;
+ }
+
+ delta_ns = time - sg_policy->last_freq_update_time;
+ return delta_ns >= sg_policy->freq_update_delay_ns;
+}
+
+static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time,
+ unsigned int next_freq)
+{
+ struct cpufreq_policy *policy = sg_policy->policy;
+
+ sg_policy->last_freq_update_time = time;
+
+ if (policy->fast_switch_enabled) {
+ if (sg_policy->next_freq == next_freq) {
+ trace_cpu_frequency(policy->cur, smp_processor_id());
+ return;
+ }
+ sg_policy->next_freq = next_freq;
+ next_freq = cpufreq_driver_fast_switch(policy, next_freq);
+ if (next_freq == CPUFREQ_ENTRY_INVALID)
+ return;
+
+ policy->cur = next_freq;
+ trace_cpu_frequency(next_freq, smp_processor_id());
+ } else if (sg_policy->next_freq != next_freq) {
+ sg_policy->next_freq = next_freq;
+ 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.
+ * @policy: cpufreq 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.
+ */
+static unsigned int get_next_freq(struct cpufreq_policy *policy,
+ unsigned long util, unsigned long max)
+{
+ unsigned int freq = arch_scale_freq_invariant() ?
+ policy->cpuinfo.max_freq : policy->cur;
+
+ return (freq + (freq >> 2)) * util / max;
+}
+
+static void sugov_update_single(struct update_util_data *hook, u64 time,
+ unsigned long util, unsigned long max)
+{
+ struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
+ struct sugov_policy *sg_policy = sg_cpu->sg_policy;
+ struct cpufreq_policy *policy = sg_policy->policy;
+ unsigned int next_f;
+
+ if (!sugov_should_update_freq(sg_policy, time))
+ return;
+
+ next_f = util == ULONG_MAX ? policy->cpuinfo.max_freq :
+ get_next_freq(policy, util, max);
+ sugov_update_commit(sg_policy, time, next_f);
+}
+
+static unsigned int sugov_next_freq_shared(struct sugov_policy *sg_policy,
+ unsigned long util, unsigned long max)
+{
+ struct cpufreq_policy *policy = sg_policy->policy;
+ unsigned int max_f = policy->cpuinfo.max_freq;
+ u64 last_freq_update_time = sg_policy->last_freq_update_time;
+ unsigned int j;
+
+ if (util == ULONG_MAX)
+ return max_f;
+
+ for_each_cpu(j, policy->cpus) {
+ struct sugov_cpu *j_sg_cpu;
+ unsigned long j_util, j_max;
+ s64 delta_ns;
+
+ if (j == smp_processor_id())
+ continue;
+
+ j_sg_cpu = &per_cpu(sugov_cpu, j);
+ /*
+ * If the CPU utilization was last updated before the previous
+ * frequency update and the time elapsed between the last update
+ * of the CPU utilization and the last frequency update is long
+ * enough, don't take the CPU into account as it probably is
+ * idle now.
+ */
+ delta_ns = last_freq_update_time - j_sg_cpu->last_update;
+ if (delta_ns > TICK_NSEC)
+ continue;
+
+ j_util = j_sg_cpu->util;
+ if (j_util == ULONG_MAX)
+ return max_f;
+
+ j_max = j_sg_cpu->max;
+ if (j_util * max > j_max * util) {
+ util = j_util;
+ max = j_max;
+ }
+ }
+
+ return get_next_freq(policy, util, max);
+}
+
+static void sugov_update_shared(struct update_util_data *hook, u64 time,
+ unsigned long util, unsigned long max)
+{
+ 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);
+
+ sg_cpu->util = util;
+ sg_cpu->max = max;
+ sg_cpu->last_update = time;
+
+ if (sugov_should_update_freq(sg_policy, time)) {
+ next_f = sugov_next_freq_shared(sg_policy, util, max);
+ sugov_update_commit(sg_policy, time, next_f);
+ }
+
+ raw_spin_unlock(&sg_policy->update_lock);
+}
+
+static void sugov_work(struct work_struct *work)
+{
+ struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work);
+
+ mutex_lock(&sg_policy->work_lock);
+ __cpufreq_driver_target(sg_policy->policy, sg_policy->next_freq,
+ CPUFREQ_RELATION_L);
+ mutex_unlock(&sg_policy->work_lock);
+
+ sg_policy->work_in_progress = false;
+}
+
+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);
+ schedule_work_on(smp_processor_id(), &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_attributes[] = {
+ &rate_limit_us.attr,
+ NULL
+};
+
+static struct kobj_type sugov_tunables_ktype = {
+ .default_attrs = sugov_attributes,
+ .sysfs_ops = &governor_sysfs_ops,
+};
+
+/********************** cpufreq governor interface *********************/
+
+static 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;
+ init_irq_work(&sg_policy->irq_work, sugov_irq_work);
+ INIT_WORK(&sg_policy->work, sugov_work);
+ mutex_init(&sg_policy->work_lock);
+ raw_spin_lock_init(&sg_policy->update_lock);
+ return sg_policy;
+}
+
+static void sugov_policy_free(struct sugov_policy *sg_policy)
+{
+ mutex_destroy(&sg_policy->work_lock);
+ kfree(sg_policy);
+}
+
+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;
+ unsigned int lat;
+ int ret = 0;
+
+ /* State should be equivalent to EXIT */
+ if (policy->governor_data)
+ return -EBUSY;
+
+ sg_policy = sugov_policy_alloc(policy);
+ if (!sg_policy)
+ return -ENOMEM;
+
+ mutex_lock(&global_tunables_lock);
+
+ if (global_tunables) {
+ if (WARN_ON(have_governor_per_policy())) {
+ ret = -EINVAL;
+ goto free_sg_policy;
+ }
+ 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 free_sg_policy;
+ }
+
+ tunables->rate_limit_us = LATENCY_MULTIPLIER;
+ lat = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
+ if (lat)
+ tunables->rate_limit_us *= lat;
+
+ 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);
+
+ cpufreq_enable_fast_switch(policy);
+ return 0;
+
+ fail:
+ policy->governor_data = NULL;
+ sugov_tunables_free(tunables);
+
+ free_sg_policy:
+ mutex_unlock(&global_tunables_lock);
+
+ sugov_policy_free(sg_policy);
+ pr_err("cpufreq: schedutil governor initialization failed (error %d)\n", ret);
+ return ret;
+}
+
+static int sugov_exit(struct cpufreq_policy *policy)
+{
+ struct sugov_policy *sg_policy = policy->governor_data;
+ struct sugov_tunables *tunables = sg_policy->tunables;
+ unsigned int count;
+
+ cpufreq_disable_fast_switch(policy);
+
+ 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_policy_free(sg_policy);
+ return 0;
+}
+
+static int sugov_start(struct cpufreq_policy *policy)
+{
+ struct sugov_policy *sg_policy = policy->governor_data;
+ 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 = UINT_MAX;
+ sg_policy->work_in_progress = false;
+ sg_policy->need_freq_update = false;
+
+ for_each_cpu(cpu, policy->cpus) {
+ struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
+
+ sg_cpu->sg_policy = sg_policy;
+ if (policy_is_shared(policy)) {
+ sg_cpu->util = ULONG_MAX;
+ sg_cpu->max = 0;
+ sg_cpu->last_update = 0;
+ cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util,
+ sugov_update_shared);
+ } else {
+ cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util,
+ sugov_update_single);
+ }
+ }
+ return 0;
+}
+
+static int 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_sched();
+
+ irq_work_sync(&sg_policy->irq_work);
+ cancel_work_sync(&sg_policy->work);
+ return 0;
+}
+
+static int 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);
+
+ if (policy->max < policy->cur)
+ __cpufreq_driver_target(policy, policy->max,
+ CPUFREQ_RELATION_H);
+ else if (policy->min > policy->cur)
+ __cpufreq_driver_target(policy, policy->min,
+ CPUFREQ_RELATION_L);
+
+ mutex_unlock(&sg_policy->work_lock);
+ }
+
+ sg_policy->need_freq_update = true;
+ return 0;
+}
+
+int sugov_governor(struct cpufreq_policy *policy, unsigned int event)
+{
+ if (event == CPUFREQ_GOV_POLICY_INIT) {
+ return sugov_init(policy);
+ } else if (policy->governor_data) {
+ switch (event) {
+ case CPUFREQ_GOV_POLICY_EXIT:
+ return sugov_exit(policy);
+ case CPUFREQ_GOV_START:
+ return sugov_start(policy);
+ case CPUFREQ_GOV_STOP:
+ return sugov_stop(policy);
+ case CPUFREQ_GOV_LIMITS:
+ return sugov_limits(policy);
+ }
+ }
+ return -EINVAL;
+}
+
+static struct cpufreq_governor schedutil_gov = {
+ .name = "schedutil",
+ .governor = sugov_governor,
+ .owner = THIS_MODULE,
+};
+
+static int __init sugov_module_init(void)
+{
+ return cpufreq_register_governor(&schedutil_gov);
+}
+
+static void __exit sugov_module_exit(void)
+{
+ cpufreq_unregister_governor(&schedutil_gov);
+}
+
+MODULE_AUTHOR("Rafael J. Wysocki <rafael.j.wysocki@intel.com>");
+MODULE_DESCRIPTION("Utilization-based CPU frequency selection");
+MODULE_LICENSE("GPL");
+
+#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
+struct cpufreq_governor *cpufreq_default_governor(void)
+{
+ return &schedutil_gov;
+}
+
+fs_initcall(sugov_module_init);
+#else
+module_init(sugov_module_init);
+#endif
+module_exit(sugov_module_exit);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index ec2e8d23527e..921d6e5d33b7 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1842,6 +1842,14 @@ static inline void cpufreq_update_util(u64 time, unsigned long util, unsigned lo
static inline void cpufreq_trigger_update(u64 time) {}
#endif /* CONFIG_CPU_FREQ */
+#ifdef arch_scale_freq_capacity
+#ifndef arch_scale_freq_invariant
+#define arch_scale_freq_invariant() (true)
+#endif
+#else /* arch_scale_freq_capacity */
+#define arch_scale_freq_invariant() (false)
+#endif
+
static inline void account_reset_rq(struct rq *rq)
{
#ifdef CONFIG_IRQ_TIME_ACCOUNTING