![Rafael J. Wysocki](/assets/img/avatar_default.png)
This change was made by commit8636fd2
(cpufreq: fix jiffies/cputime mixup in conservative/ondemand governors) before, but then it has been reverted inadvertently by commit4471a34
(cpufreq: governors: remove redundant code). The changelog of commit 8636fd2's says: The function get_cpu_idle_time_jiffy in both the conservative and ondemand governors use jiffies_to_usecs to convert a cputime value to usecs which gives the wrong value on architectures where cputime and jiffies use different units. Only matters if NO_HZ is disabled, since otherwise get_cpu_idle_time_us should already return a valid value, and get_cpu_idle_time_jiffy isn't actually called. Since now we have only one common get_cpu_idle_time_jiffy() used by both governors in question, modify it along the lines of commit8636fd2
to restore the correct behavior. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
319 lines
8.7 KiB
C
319 lines
8.7 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 <asm/cputime.h>
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#include <linux/cpufreq.h>
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#include <linux/cpumask.h>
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#include <linux/export.h>
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#include <linux/kernel_stat.h>
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#include <linux/mutex.h>
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#include <linux/tick.h>
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#include <linux/types.h>
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#include <linux/workqueue.h>
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#include "cpufreq_governor.h"
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static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
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{
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u64 idle_time;
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u64 cur_wall_time;
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u64 busy_time;
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cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
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busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
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busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
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busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
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busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
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busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
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busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
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idle_time = cur_wall_time - busy_time;
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if (wall)
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*wall = cputime_to_usecs(cur_wall_time);
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return cputime_to_usecs(idle_time);
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}
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u64 get_cpu_idle_time(unsigned int cpu, u64 *wall)
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{
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u64 idle_time = get_cpu_idle_time_us(cpu, NULL);
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if (idle_time == -1ULL)
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return get_cpu_idle_time_jiffy(cpu, wall);
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else
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idle_time += get_cpu_iowait_time_us(cpu, wall);
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return idle_time;
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}
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EXPORT_SYMBOL_GPL(get_cpu_idle_time);
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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->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 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->governor == GOV_ONDEMAND)
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ignore_nice = od_tuners->ignore_nice;
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else
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ignore_nice = cs_tuners->ignore_nice;
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policy = cdbs->cur_policy;
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/* Get Absolute Load (in terms of freq for ondemand gov) */
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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, cur_iowait_time;
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unsigned int idle_time, wall_time, iowait_time;
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unsigned int load;
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j_cdbs = dbs_data->get_cpu_cdbs(j);
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cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);
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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 (dbs_data->governor == GOV_ONDEMAND) {
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struct od_cpu_dbs_info_s *od_j_dbs_info =
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dbs_data->get_cpu_dbs_info_s(cpu);
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cur_iowait_time = get_cpu_iowait_time_us(j,
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&cur_wall_time);
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if (cur_iowait_time == -1ULL)
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cur_iowait_time = 0;
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iowait_time = (unsigned int) (cur_iowait_time -
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od_j_dbs_info->prev_cpu_iowait);
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od_j_dbs_info->prev_cpu_iowait = cur_iowait_time;
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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 subtract the
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* iowait time from the cpu idle time.
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*/
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if (od_tuners->io_is_busy && idle_time >= iowait_time)
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idle_time -= iowait_time;
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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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load = 100 * (wall_time - idle_time) / wall_time;
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if (dbs_data->governor == GOV_ONDEMAND) {
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int freq_avg = __cpufreq_driver_getavg(policy, j);
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if (freq_avg <= 0)
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freq_avg = policy->cur;
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load *= freq_avg;
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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->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 dbs_timer_init(struct dbs_data *dbs_data,
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struct cpu_dbs_common_info *cdbs, unsigned int sampling_rate)
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{
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int delay = delay_for_sampling_rate(sampling_rate);
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INIT_DEFERRABLE_WORK(&cdbs->work, dbs_data->gov_dbs_timer);
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schedule_delayed_work_on(cdbs->cpu, &cdbs->work, delay);
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}
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static inline void dbs_timer_exit(struct cpu_dbs_common_info *cdbs)
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{
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cancel_delayed_work_sync(&cdbs->work);
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}
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int cpufreq_governor_dbs(struct dbs_data *dbs_data,
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struct cpufreq_policy *policy, unsigned int event)
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{
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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_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 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 rc;
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cpu_cdbs = dbs_data->get_cpu_cdbs(cpu);
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if (dbs_data->governor == GOV_CONSERVATIVE) {
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cs_dbs_info = dbs_data->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;
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} else {
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od_dbs_info = dbs_data->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;
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}
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switch (event) {
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case CPUFREQ_GOV_START:
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if ((!cpu_online(cpu)) || (!policy->cur))
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return -EINVAL;
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mutex_lock(&dbs_data->mutex);
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dbs_data->enable++;
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cpu_cdbs->cpu = cpu;
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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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j_cdbs = dbs_data->get_cpu_cdbs(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);
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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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}
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/*
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* Start the timerschedule work, when this governor is used for
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* first time
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*/
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if (dbs_data->enable != 1)
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goto second_time;
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rc = sysfs_create_group(cpufreq_global_kobject,
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dbs_data->attr_group);
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if (rc) {
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mutex_unlock(&dbs_data->mutex);
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return rc;
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}
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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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/*
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* conservative does not implement micro like ondemand
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* governor, thus we are bound to jiffes/HZ
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*/
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if (dbs_data->governor == GOV_CONSERVATIVE) {
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struct cs_ops *ops = dbs_data->gov_ops;
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cpufreq_register_notifier(ops->notifier_block,
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CPUFREQ_TRANSITION_NOTIFIER);
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dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
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jiffies_to_usecs(10);
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} else {
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struct od_ops *ops = dbs_data->gov_ops;
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od_tuners->io_is_busy = ops->io_busy();
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}
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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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*sampling_rate = max(dbs_data->min_sampling_rate, latency *
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LATENCY_MULTIPLIER);
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second_time:
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if (dbs_data->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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struct od_ops *ops = dbs_data->gov_ops;
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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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ops->powersave_bias_init_cpu(cpu);
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}
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mutex_unlock(&dbs_data->mutex);
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mutex_init(&cpu_cdbs->timer_mutex);
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dbs_timer_init(dbs_data, cpu_cdbs, *sampling_rate);
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break;
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case CPUFREQ_GOV_STOP:
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if (dbs_data->governor == GOV_CONSERVATIVE)
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cs_dbs_info->enable = 0;
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dbs_timer_exit(cpu_cdbs);
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mutex_lock(&dbs_data->mutex);
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mutex_destroy(&cpu_cdbs->timer_mutex);
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dbs_data->enable--;
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if (!dbs_data->enable) {
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struct cs_ops *ops = dbs_data->gov_ops;
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sysfs_remove_group(cpufreq_global_kobject,
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dbs_data->attr_group);
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if (dbs_data->governor == GOV_CONSERVATIVE)
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cpufreq_unregister_notifier(ops->notifier_block,
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CPUFREQ_TRANSITION_NOTIFIER);
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}
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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(&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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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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