--- /dev/null
+/*
+ * drivers/cpufreq/cpufreq_governor.c
+ *
+ * CPUFREQ governors common code
+ *
+ * Copyright (C) 2001 Russell King
+ * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
+ * (C) 2003 Jun Nakajima <jun.nakajima@intel.com>
+ * (C) 2009 Alexander Clouter <alex@digriz.org.uk>
+ * (c) 2012 Viresh Kumar <viresh.kumar@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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/export.h>
+#include <linux/kernel_stat.h>
+#include <linux/slab.h>
+
+#include "cpufreq_governor.h"
+
+static struct attribute_group *get_sysfs_attr(struct dbs_data *dbs_data)
+{
+ if (have_governor_per_policy())
+ return dbs_data->cdata->attr_group_gov_pol;
+ else
+ return dbs_data->cdata->attr_group_gov_sys;
+}
+
+void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
+{
+ struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
+ struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+ struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
+ struct cpufreq_policy *policy;
+ unsigned int sampling_rate;
+ unsigned int max_load = 0;
+ unsigned int ignore_nice;
+ unsigned int j;
+
+ if (dbs_data->cdata->governor == GOV_ONDEMAND) {
+ struct od_cpu_dbs_info_s *od_dbs_info =
+ dbs_data->cdata->get_cpu_dbs_info_s(cpu);
+
+ /*
+ * Sometimes, the ondemand governor uses an additional
+ * multiplier to give long delays. So apply this multiplier to
+ * the 'sampling_rate', so as to keep the wake-up-from-idle
+ * detection logic a bit conservative.
+ */
+ sampling_rate = od_tuners->sampling_rate;
+ sampling_rate *= od_dbs_info->rate_mult;
+
+ ignore_nice = od_tuners->ignore_nice_load;
+ } else {
+ sampling_rate = cs_tuners->sampling_rate;
+ ignore_nice = cs_tuners->ignore_nice_load;
+ }
+
+ policy = cdbs->cur_policy;
+
+ /* Get Absolute Load */
+ for_each_cpu(j, policy->cpus) {
+ struct cpu_dbs_common_info *j_cdbs;
+ u64 cur_wall_time, cur_idle_time;
+ unsigned int idle_time, wall_time;
+ unsigned int load;
+ int io_busy = 0;
+
+ j_cdbs = dbs_data->cdata->get_cpu_cdbs(j);
+
+ /*
+ * For the purpose of ondemand, waiting for disk IO is
+ * an indication that you're performance critical, and
+ * not that the system is actually idle. So do not add
+ * the iowait time to the cpu idle time.
+ */
+ if (dbs_data->cdata->governor == GOV_ONDEMAND)
+ io_busy = od_tuners->io_is_busy;
+ cur_idle_time = get_cpu_idle_time(j, &cur_wall_time, io_busy);
+
+ wall_time = (unsigned int)
+ (cur_wall_time - j_cdbs->prev_cpu_wall);
+ j_cdbs->prev_cpu_wall = cur_wall_time;
+
+ idle_time = (unsigned int)
+ (cur_idle_time - j_cdbs->prev_cpu_idle);
+ j_cdbs->prev_cpu_idle = cur_idle_time;
+
+ if (ignore_nice) {
+ u64 cur_nice;
+ unsigned long cur_nice_jiffies;
+
+ cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] -
+ cdbs->prev_cpu_nice;
+ /*
+ * Assumption: nice time between sampling periods will
+ * be less than 2^32 jiffies for 32 bit sys
+ */
+ cur_nice_jiffies = (unsigned long)
+ cputime64_to_jiffies64(cur_nice);
+
+ cdbs->prev_cpu_nice =
+ kcpustat_cpu(j).cpustat[CPUTIME_NICE];
+ idle_time += jiffies_to_usecs(cur_nice_jiffies);
+ }
+
+ if (unlikely(!wall_time || wall_time < idle_time))
+ continue;
+
+ /*
+ * If the CPU had gone completely idle, and a task just woke up
+ * on this CPU now, it would be unfair to calculate 'load' the
+ * usual way for this elapsed time-window, because it will show
+ * near-zero load, irrespective of how CPU intensive that task
+ * actually is. This is undesirable for latency-sensitive bursty
+ * workloads.
+ *
+ * To avoid this, we reuse the 'load' from the previous
+ * time-window and give this task a chance to start with a
+ * reasonably high CPU frequency. (However, we shouldn't over-do
+ * this copy, lest we get stuck at a high load (high frequency)
+ * for too long, even when the current system load has actually
+ * dropped down. So we perform the copy only once, upon the
+ * first wake-up from idle.)
+ *
+ * Detecting this situation is easy: the governor's deferrable
+ * timer would not have fired during CPU-idle periods. Hence
+ * an unusually large 'wall_time' (as compared to the sampling
+ * rate) indicates this scenario.
+ *
+ * prev_load can be zero in two cases and we must recalculate it
+ * for both cases:
+ * - during long idle intervals
+ * - explicitly set to zero
+ */
+ if (unlikely(wall_time > (2 * sampling_rate) &&
+ j_cdbs->prev_load)) {
+ load = j_cdbs->prev_load;
+
+ /*
+ * Perform a destructive copy, to ensure that we copy
+ * the previous load only once, upon the first wake-up
+ * from idle.
+ */
+ j_cdbs->prev_load = 0;
+ } else {
+ load = 100 * (wall_time - idle_time) / wall_time;
+ j_cdbs->prev_load = load;
+ }
+
+ if (load > max_load)
+ max_load = load;
+ }
+
+ dbs_data->cdata->gov_check_cpu(cpu, max_load);
+}
+EXPORT_SYMBOL_GPL(dbs_check_cpu);
+
+static inline void __gov_queue_work(int cpu, struct dbs_data *dbs_data,
+ unsigned int delay)
+{
+ struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
+
+ mod_delayed_work_on(cpu, system_wq, &cdbs->work, delay);
+}
+
+void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
+ unsigned int delay, bool all_cpus)
+{
+ int i;
+
+ mutex_lock(&cpufreq_governor_lock);
+ if (!policy->governor_enabled)
+ goto out_unlock;
+
+ if (!all_cpus) {
+ /*
+ * Use raw_smp_processor_id() to avoid preemptible warnings.
+ * We know that this is only called with all_cpus == false from
+ * works that have been queued with *_work_on() functions and
+ * those works are canceled during CPU_DOWN_PREPARE so they
+ * can't possibly run on any other CPU.
+ */
+ __gov_queue_work(raw_smp_processor_id(), dbs_data, delay);
+ } else {
+ for_each_cpu(i, policy->cpus)
+ __gov_queue_work(i, dbs_data, delay);
+ }
+
+out_unlock:
+ mutex_unlock(&cpufreq_governor_lock);
+}
+EXPORT_SYMBOL_GPL(gov_queue_work);
+
+static inline void gov_cancel_work(struct dbs_data *dbs_data,
+ struct cpufreq_policy *policy)
+{
+ struct cpu_dbs_common_info *cdbs;
+ int i;
+
+ for_each_cpu(i, policy->cpus) {
+ cdbs = dbs_data->cdata->get_cpu_cdbs(i);
+ cancel_delayed_work_sync(&cdbs->work);
+ }
+}
+
+/* Will return if we need to evaluate cpu load again or not */
+bool need_load_eval(struct cpu_dbs_common_info *cdbs,
+ unsigned int sampling_rate)
+{
+ if (policy_is_shared(cdbs->cur_policy)) {
+ ktime_t time_now = ktime_get();
+ s64 delta_us = ktime_us_delta(time_now, cdbs->time_stamp);
+
+ /* Do nothing if we recently have sampled */
+ if (delta_us < (s64)(sampling_rate / 2))
+ return false;
+ else
+ cdbs->time_stamp = time_now;
+ }
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(need_load_eval);
+
+static void set_sampling_rate(struct dbs_data *dbs_data,
+ unsigned int sampling_rate)
+{
+ if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
+ struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
+ cs_tuners->sampling_rate = sampling_rate;
+ } else {
+ struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+ od_tuners->sampling_rate = sampling_rate;
+ }
+}
+
+int cpufreq_governor_dbs(struct cpufreq_policy *policy,
+ struct common_dbs_data *cdata, unsigned int event)
+{
+ struct dbs_data *dbs_data;
+ struct od_cpu_dbs_info_s *od_dbs_info = NULL;
+ struct cs_cpu_dbs_info_s *cs_dbs_info = NULL;
+ struct od_ops *od_ops = NULL;
+ struct od_dbs_tuners *od_tuners = NULL;
+ struct cs_dbs_tuners *cs_tuners = NULL;
+ struct cpu_dbs_common_info *cpu_cdbs;
+ unsigned int sampling_rate, latency, ignore_nice, j, cpu = policy->cpu;
+ int io_busy = 0;
+ int rc;
+
+ if (have_governor_per_policy())
+ dbs_data = policy->governor_data;
+ else
+ dbs_data = cdata->gdbs_data;
+
+ WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT));
+
+ switch (event) {
+ case CPUFREQ_GOV_POLICY_INIT:
+ if (have_governor_per_policy()) {
+ WARN_ON(dbs_data);
+ } else if (dbs_data) {
+ dbs_data->usage_count++;
+ policy->governor_data = dbs_data;
+ return 0;
+ }
+
+ dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL);
+ if (!dbs_data) {
+ pr_err("%s: POLICY_INIT: kzalloc failed\n", __func__);
+ return -ENOMEM;
+ }
+
+ dbs_data->cdata = cdata;
+ dbs_data->usage_count = 1;
+ rc = cdata->init(dbs_data);
+ if (rc) {
+ pr_err("%s: POLICY_INIT: init() failed\n", __func__);
+ kfree(dbs_data);
+ return rc;
+ }
+
+ if (!have_governor_per_policy())
+ WARN_ON(cpufreq_get_global_kobject());
+
+ rc = sysfs_create_group(get_governor_parent_kobj(policy),
+ get_sysfs_attr(dbs_data));
+ if (rc) {
+ cdata->exit(dbs_data);
+ kfree(dbs_data);
+ return rc;
+ }
+
+ policy->governor_data = dbs_data;
+
+ /* policy latency is in ns. Convert it to us first */
+ latency = policy->cpuinfo.transition_latency / 1000;
+ if (latency == 0)
+ latency = 1;
+
+ /* Bring kernel and HW constraints together */
+ dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate,
+ MIN_LATENCY_MULTIPLIER * latency);
+ set_sampling_rate(dbs_data, max(dbs_data->min_sampling_rate,
+ latency * LATENCY_MULTIPLIER));
+
+ if ((cdata->governor == GOV_CONSERVATIVE) &&
+ (!policy->governor->initialized)) {
+ struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
+
+ cpufreq_register_notifier(cs_ops->notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
+ }
+
+ if (!have_governor_per_policy())
+ cdata->gdbs_data = dbs_data;
+
+ return 0;
+ case CPUFREQ_GOV_POLICY_EXIT:
+ if (!--dbs_data->usage_count) {
+ sysfs_remove_group(get_governor_parent_kobj(policy),
+ get_sysfs_attr(dbs_data));
+
+ if (!have_governor_per_policy())
+ cpufreq_put_global_kobject();
+
+ if ((dbs_data->cdata->governor == GOV_CONSERVATIVE) &&
+ (policy->governor->initialized == 1)) {
+ struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
+
+ cpufreq_unregister_notifier(cs_ops->notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
+ }
+
+ cdata->exit(dbs_data);
+ kfree(dbs_data);
+ cdata->gdbs_data = NULL;
+ }
+
+ policy->governor_data = NULL;
+ return 0;
+ }
+
+ cpu_cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
+
+ if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
+ cs_tuners = dbs_data->tuners;
+ cs_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
+ sampling_rate = cs_tuners->sampling_rate;
+ ignore_nice = cs_tuners->ignore_nice_load;
+ } else {
+ od_tuners = dbs_data->tuners;
+ od_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
+ sampling_rate = od_tuners->sampling_rate;
+ ignore_nice = od_tuners->ignore_nice_load;
+ od_ops = dbs_data->cdata->gov_ops;
+ io_busy = od_tuners->io_is_busy;
+ }
+
+ switch (event) {
+ case CPUFREQ_GOV_START:
+ if (!policy->cur)
+ return -EINVAL;
+
+ mutex_lock(&dbs_data->mutex);
+
+ for_each_cpu(j, policy->cpus) {
+ struct cpu_dbs_common_info *j_cdbs =
+ dbs_data->cdata->get_cpu_cdbs(j);
+ unsigned int prev_load;
+
+ j_cdbs->cpu = j;
+ j_cdbs->cur_policy = policy;
+ j_cdbs->prev_cpu_idle = get_cpu_idle_time(j,
+ &j_cdbs->prev_cpu_wall, io_busy);
+
+ prev_load = (unsigned int)
+ (j_cdbs->prev_cpu_wall - j_cdbs->prev_cpu_idle);
+ j_cdbs->prev_load = 100 * prev_load /
+ (unsigned int) j_cdbs->prev_cpu_wall;
+
+ if (ignore_nice)
+ j_cdbs->prev_cpu_nice =
+ kcpustat_cpu(j).cpustat[CPUTIME_NICE];
+
+ mutex_init(&j_cdbs->timer_mutex);
+ INIT_DEFERRABLE_WORK(&j_cdbs->work,
+ dbs_data->cdata->gov_dbs_timer);
+ }
+
+ if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
+ cs_dbs_info->down_skip = 0;
+ cs_dbs_info->enable = 1;
+ cs_dbs_info->requested_freq = policy->cur;
+ } else {
+ od_dbs_info->rate_mult = 1;
+ od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
+ od_ops->powersave_bias_init_cpu(cpu);
+ }
+
+ mutex_unlock(&dbs_data->mutex);
+
+ /* Initiate timer time stamp */
+ cpu_cdbs->time_stamp = ktime_get();
+
+ gov_queue_work(dbs_data, policy,
+ delay_for_sampling_rate(sampling_rate), true);
+ break;
+
+ case CPUFREQ_GOV_STOP:
+ if (dbs_data->cdata->governor == GOV_CONSERVATIVE)
+ cs_dbs_info->enable = 0;
+
+ gov_cancel_work(dbs_data, policy);
+
+ mutex_lock(&dbs_data->mutex);
+ mutex_destroy(&cpu_cdbs->timer_mutex);
+ cpu_cdbs->cur_policy = NULL;
+
+ mutex_unlock(&dbs_data->mutex);
+
+ break;
+
+ case CPUFREQ_GOV_LIMITS:
+ mutex_lock(&dbs_data->mutex);
+ if (!cpu_cdbs->cur_policy) {
+ mutex_unlock(&dbs_data->mutex);
+ break;
+ }
+ mutex_lock(&cpu_cdbs->timer_mutex);
+ if (policy->max < cpu_cdbs->cur_policy->cur)
+ __cpufreq_driver_target(cpu_cdbs->cur_policy,
+ policy->max, CPUFREQ_RELATION_H);
+ else if (policy->min > cpu_cdbs->cur_policy->cur)
+ __cpufreq_driver_target(cpu_cdbs->cur_policy,
+ policy->min, CPUFREQ_RELATION_L);
+ dbs_check_cpu(dbs_data, cpu);
+ mutex_unlock(&cpu_cdbs->timer_mutex);
+ mutex_unlock(&dbs_data->mutex);
+ break;
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(cpufreq_governor_dbs);
Code Review / kvmfornfv.git / blobdiff