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8e0484d2b3
Notifiers are required only for conservative governor and the common governor code is unnecessarily polluted with that. Handle that from cs_init/exit() instead of cpufreq_governor_dbs(). Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
434 lines
12 KiB
C
434 lines
12 KiB
C
/*
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* drivers/cpufreq/cpufreq_governor.c
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*
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* CPUFREQ governors common code
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*
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* Copyright (C) 2001 Russell King
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* (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
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* (C) 2003 Jun Nakajima <jun.nakajima@intel.com>
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* (C) 2009 Alexander Clouter <alex@digriz.org.uk>
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* (c) 2012 Viresh Kumar <viresh.kumar@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/export.h>
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#include <linux/kernel_stat.h>
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#include <linux/slab.h>
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#include "cpufreq_governor.h"
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static struct attribute_group *get_sysfs_attr(struct dbs_data *dbs_data)
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{
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if (have_governor_per_policy())
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return dbs_data->cdata->attr_group_gov_pol;
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else
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return dbs_data->cdata->attr_group_gov_sys;
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}
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void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
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{
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struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
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struct od_dbs_tuners *od_tuners = dbs_data->tuners;
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struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
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struct cpufreq_policy *policy;
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unsigned int sampling_rate;
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unsigned int max_load = 0;
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unsigned int ignore_nice;
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unsigned int j;
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if (dbs_data->cdata->governor == GOV_ONDEMAND) {
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struct od_cpu_dbs_info_s *od_dbs_info =
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dbs_data->cdata->get_cpu_dbs_info_s(cpu);
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/*
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* Sometimes, the ondemand governor uses an additional
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* multiplier to give long delays. So apply this multiplier to
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* the 'sampling_rate', so as to keep the wake-up-from-idle
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* detection logic a bit conservative.
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*/
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sampling_rate = od_tuners->sampling_rate;
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sampling_rate *= od_dbs_info->rate_mult;
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ignore_nice = od_tuners->ignore_nice_load;
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} else {
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sampling_rate = cs_tuners->sampling_rate;
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ignore_nice = cs_tuners->ignore_nice_load;
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}
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policy = cdbs->cur_policy;
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/* Get Absolute Load */
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for_each_cpu(j, policy->cpus) {
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struct cpu_dbs_common_info *j_cdbs;
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u64 cur_wall_time, cur_idle_time;
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unsigned int idle_time, wall_time;
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unsigned int load;
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int io_busy = 0;
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j_cdbs = dbs_data->cdata->get_cpu_cdbs(j);
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/*
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* For the purpose of ondemand, waiting for disk IO is
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* an indication that you're performance critical, and
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* not that the system is actually idle. So do not add
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* the iowait time to the cpu idle time.
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*/
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if (dbs_data->cdata->governor == GOV_ONDEMAND)
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io_busy = od_tuners->io_is_busy;
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cur_idle_time = get_cpu_idle_time(j, &cur_wall_time, io_busy);
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wall_time = (unsigned int)
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(cur_wall_time - j_cdbs->prev_cpu_wall);
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j_cdbs->prev_cpu_wall = cur_wall_time;
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idle_time = (unsigned int)
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(cur_idle_time - j_cdbs->prev_cpu_idle);
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j_cdbs->prev_cpu_idle = cur_idle_time;
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if (ignore_nice) {
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u64 cur_nice;
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unsigned long cur_nice_jiffies;
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cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] -
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cdbs->prev_cpu_nice;
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/*
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* Assumption: nice time between sampling periods will
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* be less than 2^32 jiffies for 32 bit sys
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*/
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cur_nice_jiffies = (unsigned long)
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cputime64_to_jiffies64(cur_nice);
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cdbs->prev_cpu_nice =
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kcpustat_cpu(j).cpustat[CPUTIME_NICE];
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idle_time += jiffies_to_usecs(cur_nice_jiffies);
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}
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if (unlikely(!wall_time || wall_time < idle_time))
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continue;
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/*
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* If the CPU had gone completely idle, and a task just woke up
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* on this CPU now, it would be unfair to calculate 'load' the
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* usual way for this elapsed time-window, because it will show
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* near-zero load, irrespective of how CPU intensive that task
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* actually is. This is undesirable for latency-sensitive bursty
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* workloads.
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*
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* To avoid this, we reuse the 'load' from the previous
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* time-window and give this task a chance to start with a
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* reasonably high CPU frequency. (However, we shouldn't over-do
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* this copy, lest we get stuck at a high load (high frequency)
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* for too long, even when the current system load has actually
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* dropped down. So we perform the copy only once, upon the
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* first wake-up from idle.)
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*
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* Detecting this situation is easy: the governor's deferrable
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* timer would not have fired during CPU-idle periods. Hence
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* an unusually large 'wall_time' (as compared to the sampling
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* rate) indicates this scenario.
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*
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* prev_load can be zero in two cases and we must recalculate it
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* for both cases:
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* - during long idle intervals
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* - explicitly set to zero
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*/
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if (unlikely(wall_time > (2 * sampling_rate) &&
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j_cdbs->prev_load)) {
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load = j_cdbs->prev_load;
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/*
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* Perform a destructive copy, to ensure that we copy
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* the previous load only once, upon the first wake-up
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* from idle.
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*/
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j_cdbs->prev_load = 0;
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} else {
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load = 100 * (wall_time - idle_time) / wall_time;
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j_cdbs->prev_load = load;
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}
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if (load > max_load)
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max_load = load;
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}
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dbs_data->cdata->gov_check_cpu(cpu, max_load);
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}
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EXPORT_SYMBOL_GPL(dbs_check_cpu);
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static inline void __gov_queue_work(int cpu, struct dbs_data *dbs_data,
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unsigned int delay)
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{
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struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
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mod_delayed_work_on(cpu, system_wq, &cdbs->work, delay);
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}
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void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
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unsigned int delay, bool all_cpus)
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{
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int i;
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mutex_lock(&cpufreq_governor_lock);
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if (!policy->governor_enabled)
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goto out_unlock;
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if (!all_cpus) {
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/*
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* Use raw_smp_processor_id() to avoid preemptible warnings.
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* We know that this is only called with all_cpus == false from
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* works that have been queued with *_work_on() functions and
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* those works are canceled during CPU_DOWN_PREPARE so they
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* can't possibly run on any other CPU.
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*/
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__gov_queue_work(raw_smp_processor_id(), dbs_data, delay);
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} else {
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for_each_cpu(i, policy->cpus)
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__gov_queue_work(i, dbs_data, delay);
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}
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out_unlock:
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mutex_unlock(&cpufreq_governor_lock);
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}
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EXPORT_SYMBOL_GPL(gov_queue_work);
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static inline void gov_cancel_work(struct dbs_data *dbs_data,
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struct cpufreq_policy *policy)
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{
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struct cpu_dbs_common_info *cdbs;
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int i;
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for_each_cpu(i, policy->cpus) {
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cdbs = dbs_data->cdata->get_cpu_cdbs(i);
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cancel_delayed_work_sync(&cdbs->work);
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}
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}
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/* Will return if we need to evaluate cpu load again or not */
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bool need_load_eval(struct cpu_dbs_common_info *cdbs,
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unsigned int sampling_rate)
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{
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if (policy_is_shared(cdbs->cur_policy)) {
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ktime_t time_now = ktime_get();
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s64 delta_us = ktime_us_delta(time_now, cdbs->time_stamp);
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/* Do nothing if we recently have sampled */
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if (delta_us < (s64)(sampling_rate / 2))
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return false;
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else
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cdbs->time_stamp = time_now;
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}
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return true;
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}
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EXPORT_SYMBOL_GPL(need_load_eval);
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static void set_sampling_rate(struct dbs_data *dbs_data,
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unsigned int sampling_rate)
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{
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if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
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struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
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cs_tuners->sampling_rate = sampling_rate;
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} else {
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struct od_dbs_tuners *od_tuners = dbs_data->tuners;
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od_tuners->sampling_rate = sampling_rate;
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}
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}
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int cpufreq_governor_dbs(struct cpufreq_policy *policy,
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struct common_dbs_data *cdata, unsigned int event)
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{
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struct dbs_data *dbs_data;
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struct od_cpu_dbs_info_s *od_dbs_info = NULL;
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struct cs_cpu_dbs_info_s *cs_dbs_info = NULL;
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struct od_ops *od_ops = NULL;
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struct od_dbs_tuners *od_tuners = NULL;
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struct cs_dbs_tuners *cs_tuners = NULL;
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struct cpu_dbs_common_info *cpu_cdbs;
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unsigned int sampling_rate, latency, ignore_nice, j, cpu = policy->cpu;
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int io_busy = 0;
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int rc;
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if (have_governor_per_policy())
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dbs_data = policy->governor_data;
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else
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dbs_data = cdata->gdbs_data;
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WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT));
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switch (event) {
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case CPUFREQ_GOV_POLICY_INIT:
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if (have_governor_per_policy()) {
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WARN_ON(dbs_data);
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} else if (dbs_data) {
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dbs_data->usage_count++;
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policy->governor_data = dbs_data;
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return 0;
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}
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dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL);
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if (!dbs_data) {
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pr_err("%s: POLICY_INIT: kzalloc failed\n", __func__);
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return -ENOMEM;
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}
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dbs_data->cdata = cdata;
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dbs_data->usage_count = 1;
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rc = cdata->init(dbs_data, !policy->governor->initialized);
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if (rc) {
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pr_err("%s: POLICY_INIT: init() failed\n", __func__);
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kfree(dbs_data);
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return rc;
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}
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if (!have_governor_per_policy())
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WARN_ON(cpufreq_get_global_kobject());
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rc = sysfs_create_group(get_governor_parent_kobj(policy),
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get_sysfs_attr(dbs_data));
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if (rc) {
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cdata->exit(dbs_data, !policy->governor->initialized);
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kfree(dbs_data);
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return rc;
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}
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policy->governor_data = dbs_data;
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/* policy latency is in ns. Convert it to us first */
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latency = policy->cpuinfo.transition_latency / 1000;
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if (latency == 0)
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latency = 1;
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/* Bring kernel and HW constraints together */
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dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate,
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MIN_LATENCY_MULTIPLIER * latency);
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set_sampling_rate(dbs_data, max(dbs_data->min_sampling_rate,
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latency * LATENCY_MULTIPLIER));
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if (!have_governor_per_policy())
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cdata->gdbs_data = dbs_data;
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return 0;
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case CPUFREQ_GOV_POLICY_EXIT:
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if (!--dbs_data->usage_count) {
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sysfs_remove_group(get_governor_parent_kobj(policy),
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get_sysfs_attr(dbs_data));
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if (!have_governor_per_policy())
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cpufreq_put_global_kobject();
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cdata->exit(dbs_data, policy->governor->initialized == 1);
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kfree(dbs_data);
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cdata->gdbs_data = NULL;
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}
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policy->governor_data = NULL;
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return 0;
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}
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cpu_cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
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if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
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cs_tuners = dbs_data->tuners;
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cs_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
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sampling_rate = cs_tuners->sampling_rate;
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ignore_nice = cs_tuners->ignore_nice_load;
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} else {
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od_tuners = dbs_data->tuners;
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od_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
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sampling_rate = od_tuners->sampling_rate;
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ignore_nice = od_tuners->ignore_nice_load;
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od_ops = dbs_data->cdata->gov_ops;
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io_busy = od_tuners->io_is_busy;
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}
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switch (event) {
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case CPUFREQ_GOV_START:
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if (!policy->cur)
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return -EINVAL;
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mutex_lock(&dbs_data->mutex);
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for_each_cpu(j, policy->cpus) {
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struct cpu_dbs_common_info *j_cdbs =
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dbs_data->cdata->get_cpu_cdbs(j);
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unsigned int prev_load;
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j_cdbs->cpu = j;
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j_cdbs->cur_policy = policy;
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j_cdbs->prev_cpu_idle = get_cpu_idle_time(j,
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&j_cdbs->prev_cpu_wall, io_busy);
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prev_load = (unsigned int)
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(j_cdbs->prev_cpu_wall - j_cdbs->prev_cpu_idle);
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j_cdbs->prev_load = 100 * prev_load /
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(unsigned int) j_cdbs->prev_cpu_wall;
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if (ignore_nice)
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j_cdbs->prev_cpu_nice =
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kcpustat_cpu(j).cpustat[CPUTIME_NICE];
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mutex_init(&j_cdbs->timer_mutex);
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INIT_DEFERRABLE_WORK(&j_cdbs->work,
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dbs_data->cdata->gov_dbs_timer);
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}
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if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
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cs_dbs_info->down_skip = 0;
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cs_dbs_info->enable = 1;
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cs_dbs_info->requested_freq = policy->cur;
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} else {
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od_dbs_info->rate_mult = 1;
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od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
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od_ops->powersave_bias_init_cpu(cpu);
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}
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mutex_unlock(&dbs_data->mutex);
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/* Initiate timer time stamp */
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cpu_cdbs->time_stamp = ktime_get();
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gov_queue_work(dbs_data, policy,
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delay_for_sampling_rate(sampling_rate), true);
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break;
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case CPUFREQ_GOV_STOP:
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if (dbs_data->cdata->governor == GOV_CONSERVATIVE)
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cs_dbs_info->enable = 0;
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gov_cancel_work(dbs_data, policy);
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mutex_lock(&dbs_data->mutex);
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mutex_destroy(&cpu_cdbs->timer_mutex);
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cpu_cdbs->cur_policy = NULL;
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mutex_unlock(&dbs_data->mutex);
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break;
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case CPUFREQ_GOV_LIMITS:
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mutex_lock(&dbs_data->mutex);
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if (!cpu_cdbs->cur_policy) {
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mutex_unlock(&dbs_data->mutex);
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break;
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}
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mutex_lock(&cpu_cdbs->timer_mutex);
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if (policy->max < cpu_cdbs->cur_policy->cur)
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__cpufreq_driver_target(cpu_cdbs->cur_policy,
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policy->max, CPUFREQ_RELATION_H);
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else if (policy->min > cpu_cdbs->cur_policy->cur)
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__cpufreq_driver_target(cpu_cdbs->cur_policy,
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policy->min, CPUFREQ_RELATION_L);
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dbs_check_cpu(dbs_data, cpu);
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mutex_unlock(&cpu_cdbs->timer_mutex);
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mutex_unlock(&dbs_data->mutex);
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break;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(cpufreq_governor_dbs);
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