--- /dev/null
+/*
+ * Copyright (C) 2015 Michael Turquette <mturquette@linaro.org>
+ *
+ * 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/kthread.h>
+#include <linux/percpu.h>
+#include <linux/irq_work.h>
+#include <linux/delay.h>
+#include <linux/string.h>
+
+#include "sched.h"
+
+#define THROTTLE_NSEC 50000000 /* 50ms default */
+
+struct static_key __read_mostly __sched_freq = STATIC_KEY_INIT_FALSE;
+static bool __read_mostly cpufreq_driver_slow;
+
+#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHED
+static struct cpufreq_governor cpufreq_gov_sched;
+#endif
+
+static DEFINE_PER_CPU(unsigned long, enabled);
+DEFINE_PER_CPU(struct sched_capacity_reqs, cpu_sched_capacity_reqs);
+
+/**
+ * gov_data - per-policy data internal to the governor
+ * @throttle: next throttling period expiry. Derived from throttle_nsec
+ * @throttle_nsec: throttle period length in nanoseconds
+ * @task: worker thread for dvfs transition that may block/sleep
+ * @irq_work: callback used to wake up worker thread
+ * @requested_freq: last frequency requested by the sched governor
+ *
+ * struct gov_data is the per-policy cpufreq_sched-specific data structure. A
+ * per-policy instance of it is created when the cpufreq_sched governor receives
+ * the CPUFREQ_GOV_START condition and a pointer to it exists in the gov_data
+ * member of struct cpufreq_policy.
+ *
+ * Readers of this data must call down_read(policy->rwsem). Writers must
+ * call down_write(policy->rwsem).
+ */
+struct gov_data {
+ ktime_t throttle;
+ unsigned int throttle_nsec;
+ struct task_struct *task;
+ struct irq_work irq_work;
+ unsigned int requested_freq;
+};
+
+static void cpufreq_sched_try_driver_target(struct cpufreq_policy *policy,
+ unsigned int freq)
+{
+ struct gov_data *gd = policy->governor_data;
+
+ /* avoid race with cpufreq_sched_stop */
+ if (!down_write_trylock(&policy->rwsem))
+ return;
+
+ __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
+
+ gd->throttle = ktime_add_ns(ktime_get(), gd->throttle_nsec);
+ up_write(&policy->rwsem);
+}
+
+static bool finish_last_request(struct gov_data *gd)
+{
+ ktime_t now = ktime_get();
+
+ if (ktime_after(now, gd->throttle))
+ return false;
+
+ while (1) {
+ int usec_left = ktime_to_ns(ktime_sub(gd->throttle, now));
+
+ usec_left /= NSEC_PER_USEC;
+ usleep_range(usec_left, usec_left + 100);
+ now = ktime_get();
+ if (ktime_after(now, gd->throttle))
+ return true;
+ }
+}
+
+/*
+ * we pass in struct cpufreq_policy. This is safe because changing out the
+ * policy requires a call to __cpufreq_governor(policy, CPUFREQ_GOV_STOP),
+ * which tears down all of the data structures and __cpufreq_governor(policy,
+ * CPUFREQ_GOV_START) will do a full rebuild, including this kthread with the
+ * new policy pointer
+ */
+static int cpufreq_sched_thread(void *data)
+{
+ struct sched_param param;
+ struct cpufreq_policy *policy;
+ struct gov_data *gd;
+ unsigned int new_request = 0;
+ unsigned int last_request = 0;
+ int ret;
+
+ policy = (struct cpufreq_policy *) data;
+ gd = policy->governor_data;
+
+ param.sched_priority = 50;
+ ret = sched_setscheduler_nocheck(gd->task, SCHED_FIFO, ¶m);
+ if (ret) {
+ pr_warn("%s: failed to set SCHED_FIFO\n", __func__);
+ do_exit(-EINVAL);
+ } else {
+ pr_debug("%s: kthread (%d) set to SCHED_FIFO\n",
+ __func__, gd->task->pid);
+ }
+
+ do {
+ set_current_state(TASK_INTERRUPTIBLE);
+ new_request = gd->requested_freq;
+ if (new_request == last_request) {
+ schedule();
+ } else {
+ /*
+ * if the frequency thread sleeps while waiting to be
+ * unthrottled, start over to check for a newer request
+ */
+ if (finish_last_request(gd))
+ continue;
+ last_request = new_request;
+ cpufreq_sched_try_driver_target(policy, new_request);
+ }
+ } while (!kthread_should_stop());
+
+ return 0;
+}
+
+static void cpufreq_sched_irq_work(struct irq_work *irq_work)
+{
+ struct gov_data *gd;
+
+ gd = container_of(irq_work, struct gov_data, irq_work);
+ if (!gd)
+ return;
+
+ wake_up_process(gd->task);
+}
+
+static void update_fdomain_capacity_request(int cpu)
+{
+ unsigned int freq_new, index_new, cpu_tmp;
+ struct cpufreq_policy *policy;
+ struct gov_data *gd;
+ unsigned long capacity = 0;
+
+ /*
+ * Avoid grabbing the policy if possible. A test is still
+ * required after locking the CPU's policy to avoid racing
+ * with the governor changing.
+ */
+ if (!per_cpu(enabled, cpu))
+ return;
+
+ policy = cpufreq_cpu_get(cpu);
+ if (IS_ERR_OR_NULL(policy))
+ return;
+
+ if (policy->governor != &cpufreq_gov_sched ||
+ !policy->governor_data)
+ goto out;
+
+ gd = policy->governor_data;
+
+ /* find max capacity requested by cpus in this policy */
+ for_each_cpu(cpu_tmp, policy->cpus) {
+ struct sched_capacity_reqs *scr;
+
+ scr = &per_cpu(cpu_sched_capacity_reqs, cpu_tmp);
+ capacity = max(capacity, scr->total);
+ }
+
+ /* Convert the new maximum capacity request into a cpu frequency */
+ freq_new = capacity * policy->max >> SCHED_CAPACITY_SHIFT;
+ if (cpufreq_frequency_table_target(policy, policy->freq_table,
+ freq_new, CPUFREQ_RELATION_L,
+ &index_new))
+ goto out;
+ freq_new = policy->freq_table[index_new].frequency;
+
+ if (freq_new == gd->requested_freq)
+ goto out;
+
+ gd->requested_freq = freq_new;
+
+ /*
+ * Throttling is not yet supported on platforms with fast cpufreq
+ * drivers.
+ */
+ if (cpufreq_driver_slow)
+ irq_work_queue_on(&gd->irq_work, cpu);
+ else
+ cpufreq_sched_try_driver_target(policy, freq_new);
+
+out:
+ cpufreq_cpu_put(policy);
+}
+
+void update_cpu_capacity_request(int cpu, bool request)
+{
+ unsigned long new_capacity;
+ struct sched_capacity_reqs *scr;
+
+ /* The rq lock serializes access to the CPU's sched_capacity_reqs. */
+ lockdep_assert_held(&cpu_rq(cpu)->lock);
+
+ scr = &per_cpu(cpu_sched_capacity_reqs, cpu);
+
+ new_capacity = scr->cfs + scr->rt;
+ new_capacity = new_capacity * capacity_margin
+ / SCHED_CAPACITY_SCALE;
+ new_capacity += scr->dl;
+
+ if (new_capacity == scr->total)
+ return;
+
+ scr->total = new_capacity;
+ if (request)
+ update_fdomain_capacity_request(cpu);
+}
+
+static inline void set_sched_freq(void)
+{
+ static_key_slow_inc(&__sched_freq);
+}
+
+static inline void clear_sched_freq(void)
+{
+ static_key_slow_dec(&__sched_freq);
+}
+
+static int cpufreq_sched_policy_init(struct cpufreq_policy *policy)
+{
+ struct gov_data *gd;
+ int cpu;
+
+ for_each_cpu(cpu, policy->cpus)
+ memset(&per_cpu(cpu_sched_capacity_reqs, cpu), 0,
+ sizeof(struct sched_capacity_reqs));
+
+ gd = kzalloc(sizeof(*gd), GFP_KERNEL);
+ if (!gd)
+ return -ENOMEM;
+
+ gd->throttle_nsec = policy->cpuinfo.transition_latency ?
+ policy->cpuinfo.transition_latency :
+ THROTTLE_NSEC;
+ pr_debug("%s: throttle threshold = %u [ns]\n",
+ __func__, gd->throttle_nsec);
+
+ if (cpufreq_driver_is_slow()) {
+ cpufreq_driver_slow = true;
+ gd->task = kthread_create(cpufreq_sched_thread, policy,
+ "kschedfreq:%d",
+ cpumask_first(policy->related_cpus));
+ if (IS_ERR_OR_NULL(gd->task)) {
+ pr_err("%s: failed to create kschedfreq thread\n",
+ __func__);
+ goto err;
+ }
+ get_task_struct(gd->task);
+ kthread_bind_mask(gd->task, policy->related_cpus);
+ wake_up_process(gd->task);
+ init_irq_work(&gd->irq_work, cpufreq_sched_irq_work);
+ }
+
+ policy->governor_data = gd;
+ set_sched_freq();
+
+ return 0;
+
+err:
+ kfree(gd);
+ return -ENOMEM;
+}
+
+static int cpufreq_sched_policy_exit(struct cpufreq_policy *policy)
+{
+ struct gov_data *gd = policy->governor_data;
+
+ clear_sched_freq();
+ if (cpufreq_driver_slow) {
+ kthread_stop(gd->task);
+ put_task_struct(gd->task);
+ }
+
+ policy->governor_data = NULL;
+
+ kfree(gd);
+ return 0;
+}
+
+static int cpufreq_sched_start(struct cpufreq_policy *policy)
+{
+ int cpu;
+
+ for_each_cpu(cpu, policy->cpus)
+ per_cpu(enabled, cpu) = 1;
+
+ return 0;
+}
+
+static int cpufreq_sched_stop(struct cpufreq_policy *policy)
+{
+ int cpu;
+
+ for_each_cpu(cpu, policy->cpus)
+ per_cpu(enabled, cpu) = 0;
+
+ return 0;
+}
+
+static int cpufreq_sched_setup(struct cpufreq_policy *policy,
+ unsigned int event)
+{
+ switch (event) {
+ case CPUFREQ_GOV_POLICY_INIT:
+ return cpufreq_sched_policy_init(policy);
+ case CPUFREQ_GOV_POLICY_EXIT:
+ return cpufreq_sched_policy_exit(policy);
+ case CPUFREQ_GOV_START:
+ return cpufreq_sched_start(policy);
+ case CPUFREQ_GOV_STOP:
+ return cpufreq_sched_stop(policy);
+ case CPUFREQ_GOV_LIMITS:
+ break;
+ }
+ return 0;
+}
+
+#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHED
+static
+#endif
+struct cpufreq_governor cpufreq_gov_sched = {
+ .name = "sched",
+ .governor = cpufreq_sched_setup,
+ .owner = THIS_MODULE,
+};
+
+static int __init cpufreq_sched_init(void)
+{
+ int cpu;
+
+ for_each_cpu(cpu, cpu_possible_mask)
+ per_cpu(enabled, cpu) = 0;
+ return cpufreq_register_governor(&cpufreq_gov_sched);
+}
+
+/* Try to make this the default governor */
+fs_initcall(cpufreq_sched_init);
}
#endif
+#ifdef CONFIG_CPU_FREQ_GOV_SCHED
+extern unsigned int capacity_margin;
+extern struct static_key __sched_freq;
+
+static inline bool sched_freq(void)
+{
+ return static_key_false(&__sched_freq);
+}
+
+DECLARE_PER_CPU(struct sched_capacity_reqs, cpu_sched_capacity_reqs);
+void update_cpu_capacity_request(int cpu, bool request);
+
+static inline void set_cfs_cpu_capacity(int cpu, bool request,
+ unsigned long capacity)
+{
+ if (per_cpu(cpu_sched_capacity_reqs, cpu).cfs != capacity) {
+ per_cpu(cpu_sched_capacity_reqs, cpu).cfs = capacity;
+ update_cpu_capacity_request(cpu, request);
+ }
+}
+
+static inline void set_rt_cpu_capacity(int cpu, bool request,
+ unsigned long capacity)
+{
+ if (per_cpu(cpu_sched_capacity_reqs, cpu).rt != capacity) {
+ per_cpu(cpu_sched_capacity_reqs, cpu).rt = capacity;
+ update_cpu_capacity_request(cpu, request);
+ }
+}
+
+static inline void set_dl_cpu_capacity(int cpu, bool request,
+ unsigned long capacity)
+{
+ if (per_cpu(cpu_sched_capacity_reqs, cpu).dl != capacity) {
+ per_cpu(cpu_sched_capacity_reqs, cpu).dl = capacity;
+ update_cpu_capacity_request(cpu, request);
+ }
+}
+#else
+static inline bool sched_freq(void) { return false; }
+static inline void set_cfs_cpu_capacity(int cpu, bool request,
+ unsigned long capacity)
+{ }
+static inline void set_rt_cpu_capacity(int cpu, bool request,
+ unsigned long capacity)
+{ }
+static inline void set_dl_cpu_capacity(int cpu, bool request,
+ unsigned long capacity)
+{ }
+#endif
+
static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
{
rq->rt_avg += rt_delta * arch_scale_freq_capacity(NULL, cpu_of(rq));
projects / GitHub / exynos8895 / android_kernel_samsung_universal8895.git / commitdiff