mirror of https://gitee.com/openkylin/linux.git
577 lines
15 KiB
C
577 lines
15 KiB
C
/*
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* CPUFreq governor based on scheduler-provided CPU utilization data.
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*
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* Copyright (C) 2016, Intel Corporation
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* Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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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/cpufreq.h>
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#include <linux/slab.h>
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#include <trace/events/power.h>
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#include "sched.h"
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struct sugov_tunables {
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struct gov_attr_set attr_set;
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unsigned int rate_limit_us;
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};
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struct sugov_policy {
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struct cpufreq_policy *policy;
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struct sugov_tunables *tunables;
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struct list_head tunables_hook;
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raw_spinlock_t update_lock; /* For shared policies */
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u64 last_freq_update_time;
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s64 freq_update_delay_ns;
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unsigned int next_freq;
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/* The next fields are only needed if fast switch cannot be used. */
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struct irq_work irq_work;
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struct work_struct work;
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struct mutex work_lock;
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bool work_in_progress;
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bool need_freq_update;
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};
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struct sugov_cpu {
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struct update_util_data update_util;
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struct sugov_policy *sg_policy;
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unsigned int cached_raw_freq;
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unsigned long iowait_boost;
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unsigned long iowait_boost_max;
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u64 last_update;
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/* The fields below are only needed when sharing a policy. */
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unsigned long util;
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unsigned long max;
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unsigned int flags;
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};
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static DEFINE_PER_CPU(struct sugov_cpu, sugov_cpu);
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/************************ Governor internals ***********************/
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static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time)
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{
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s64 delta_ns;
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if (sg_policy->work_in_progress)
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return false;
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if (unlikely(sg_policy->need_freq_update)) {
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sg_policy->need_freq_update = false;
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/*
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* This happens when limits change, so forget the previous
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* next_freq value and force an update.
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*/
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sg_policy->next_freq = UINT_MAX;
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return true;
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}
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delta_ns = time - sg_policy->last_freq_update_time;
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return delta_ns >= sg_policy->freq_update_delay_ns;
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}
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static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time,
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unsigned int next_freq)
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{
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struct cpufreq_policy *policy = sg_policy->policy;
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sg_policy->last_freq_update_time = time;
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if (policy->fast_switch_enabled) {
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if (sg_policy->next_freq == next_freq) {
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trace_cpu_frequency(policy->cur, smp_processor_id());
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return;
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}
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sg_policy->next_freq = next_freq;
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next_freq = cpufreq_driver_fast_switch(policy, next_freq);
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if (next_freq == CPUFREQ_ENTRY_INVALID)
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return;
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policy->cur = next_freq;
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trace_cpu_frequency(next_freq, smp_processor_id());
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} else if (sg_policy->next_freq != next_freq) {
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sg_policy->next_freq = next_freq;
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sg_policy->work_in_progress = true;
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irq_work_queue(&sg_policy->irq_work);
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}
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}
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/**
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* get_next_freq - Compute a new frequency for a given cpufreq policy.
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* @sg_cpu: schedutil cpu object to compute the new frequency for.
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* @util: Current CPU utilization.
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* @max: CPU capacity.
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*
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* If the utilization is frequency-invariant, choose the new frequency to be
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* proportional to it, that is
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*
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* next_freq = C * max_freq * util / max
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*
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* Otherwise, approximate the would-be frequency-invariant utilization by
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* util_raw * (curr_freq / max_freq) which leads to
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*
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* next_freq = C * curr_freq * util_raw / max
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*
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* Take C = 1.25 for the frequency tipping point at (util / max) = 0.8.
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*
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* The lowest driver-supported frequency which is equal or greater than the raw
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* next_freq (as calculated above) is returned, subject to policy min/max and
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* cpufreq driver limitations.
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*/
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static unsigned int get_next_freq(struct sugov_cpu *sg_cpu, unsigned long util,
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unsigned long max)
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{
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struct sugov_policy *sg_policy = sg_cpu->sg_policy;
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struct cpufreq_policy *policy = sg_policy->policy;
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unsigned int freq = arch_scale_freq_invariant() ?
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policy->cpuinfo.max_freq : policy->cur;
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freq = (freq + (freq >> 2)) * util / max;
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if (freq == sg_cpu->cached_raw_freq && sg_policy->next_freq != UINT_MAX)
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return sg_policy->next_freq;
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sg_cpu->cached_raw_freq = freq;
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return cpufreq_driver_resolve_freq(policy, freq);
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}
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static void sugov_get_util(unsigned long *util, unsigned long *max)
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{
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struct rq *rq = this_rq();
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unsigned long cfs_max;
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cfs_max = arch_scale_cpu_capacity(NULL, smp_processor_id());
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*util = min(rq->cfs.avg.util_avg, cfs_max);
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*max = cfs_max;
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}
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static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
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unsigned int flags)
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{
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if (flags & SCHED_CPUFREQ_IOWAIT) {
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sg_cpu->iowait_boost = sg_cpu->iowait_boost_max;
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} else if (sg_cpu->iowait_boost) {
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s64 delta_ns = time - sg_cpu->last_update;
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/* Clear iowait_boost if the CPU apprears to have been idle. */
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if (delta_ns > TICK_NSEC)
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sg_cpu->iowait_boost = 0;
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}
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}
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static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, unsigned long *util,
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unsigned long *max)
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{
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unsigned long boost_util = sg_cpu->iowait_boost;
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unsigned long boost_max = sg_cpu->iowait_boost_max;
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if (!boost_util)
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return;
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if (*util * boost_max < *max * boost_util) {
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*util = boost_util;
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*max = boost_max;
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}
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sg_cpu->iowait_boost >>= 1;
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}
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static void sugov_update_single(struct update_util_data *hook, u64 time,
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unsigned int flags)
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{
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struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
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struct sugov_policy *sg_policy = sg_cpu->sg_policy;
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struct cpufreq_policy *policy = sg_policy->policy;
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unsigned long util, max;
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unsigned int next_f;
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sugov_set_iowait_boost(sg_cpu, time, flags);
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sg_cpu->last_update = time;
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if (!sugov_should_update_freq(sg_policy, time))
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return;
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if (flags & SCHED_CPUFREQ_RT_DL) {
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next_f = policy->cpuinfo.max_freq;
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} else {
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sugov_get_util(&util, &max);
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sugov_iowait_boost(sg_cpu, &util, &max);
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next_f = get_next_freq(sg_cpu, util, max);
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}
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sugov_update_commit(sg_policy, time, next_f);
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}
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static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu,
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unsigned long util, unsigned long max,
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unsigned int flags)
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{
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struct sugov_policy *sg_policy = sg_cpu->sg_policy;
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struct cpufreq_policy *policy = sg_policy->policy;
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unsigned int max_f = policy->cpuinfo.max_freq;
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u64 last_freq_update_time = sg_policy->last_freq_update_time;
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unsigned int j;
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if (flags & SCHED_CPUFREQ_RT_DL)
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return max_f;
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sugov_iowait_boost(sg_cpu, &util, &max);
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for_each_cpu(j, policy->cpus) {
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struct sugov_cpu *j_sg_cpu;
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unsigned long j_util, j_max;
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s64 delta_ns;
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if (j == smp_processor_id())
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continue;
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j_sg_cpu = &per_cpu(sugov_cpu, j);
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/*
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* If the CPU utilization was last updated before the previous
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* frequency update and the time elapsed between the last update
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* of the CPU utilization and the last frequency update is long
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* enough, don't take the CPU into account as it probably is
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* idle now (and clear iowait_boost for it).
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*/
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delta_ns = last_freq_update_time - j_sg_cpu->last_update;
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if (delta_ns > TICK_NSEC) {
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j_sg_cpu->iowait_boost = 0;
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continue;
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}
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if (j_sg_cpu->flags & SCHED_CPUFREQ_RT_DL)
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return max_f;
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j_util = j_sg_cpu->util;
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j_max = j_sg_cpu->max;
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if (j_util * max > j_max * util) {
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util = j_util;
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max = j_max;
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}
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sugov_iowait_boost(j_sg_cpu, &util, &max);
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}
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return get_next_freq(sg_cpu, util, max);
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}
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static void sugov_update_shared(struct update_util_data *hook, u64 time,
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unsigned int flags)
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{
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struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
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struct sugov_policy *sg_policy = sg_cpu->sg_policy;
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unsigned long util, max;
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unsigned int next_f;
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sugov_get_util(&util, &max);
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raw_spin_lock(&sg_policy->update_lock);
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sg_cpu->util = util;
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sg_cpu->max = max;
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sg_cpu->flags = flags;
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sugov_set_iowait_boost(sg_cpu, time, flags);
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sg_cpu->last_update = time;
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if (sugov_should_update_freq(sg_policy, time)) {
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next_f = sugov_next_freq_shared(sg_cpu, util, max, flags);
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sugov_update_commit(sg_policy, time, next_f);
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}
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raw_spin_unlock(&sg_policy->update_lock);
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}
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static void sugov_work(struct work_struct *work)
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{
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struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work);
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mutex_lock(&sg_policy->work_lock);
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__cpufreq_driver_target(sg_policy->policy, sg_policy->next_freq,
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CPUFREQ_RELATION_L);
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mutex_unlock(&sg_policy->work_lock);
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sg_policy->work_in_progress = false;
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}
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static void sugov_irq_work(struct irq_work *irq_work)
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{
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struct sugov_policy *sg_policy;
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sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
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schedule_work_on(smp_processor_id(), &sg_policy->work);
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}
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/************************** sysfs interface ************************/
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static struct sugov_tunables *global_tunables;
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static DEFINE_MUTEX(global_tunables_lock);
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static inline struct sugov_tunables *to_sugov_tunables(struct gov_attr_set *attr_set)
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{
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return container_of(attr_set, struct sugov_tunables, attr_set);
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}
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static ssize_t rate_limit_us_show(struct gov_attr_set *attr_set, char *buf)
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{
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struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
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return sprintf(buf, "%u\n", tunables->rate_limit_us);
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}
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static ssize_t rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf,
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size_t count)
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{
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struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
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struct sugov_policy *sg_policy;
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unsigned int rate_limit_us;
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if (kstrtouint(buf, 10, &rate_limit_us))
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return -EINVAL;
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tunables->rate_limit_us = rate_limit_us;
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list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook)
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sg_policy->freq_update_delay_ns = rate_limit_us * NSEC_PER_USEC;
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return count;
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}
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static struct governor_attr rate_limit_us = __ATTR_RW(rate_limit_us);
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static struct attribute *sugov_attributes[] = {
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&rate_limit_us.attr,
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NULL
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};
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static struct kobj_type sugov_tunables_ktype = {
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.default_attrs = sugov_attributes,
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.sysfs_ops = &governor_sysfs_ops,
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};
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/********************** cpufreq governor interface *********************/
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static struct cpufreq_governor schedutil_gov;
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static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy)
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{
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struct sugov_policy *sg_policy;
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sg_policy = kzalloc(sizeof(*sg_policy), GFP_KERNEL);
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if (!sg_policy)
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return NULL;
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sg_policy->policy = policy;
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init_irq_work(&sg_policy->irq_work, sugov_irq_work);
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INIT_WORK(&sg_policy->work, sugov_work);
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mutex_init(&sg_policy->work_lock);
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raw_spin_lock_init(&sg_policy->update_lock);
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return sg_policy;
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}
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static void sugov_policy_free(struct sugov_policy *sg_policy)
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{
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mutex_destroy(&sg_policy->work_lock);
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kfree(sg_policy);
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}
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static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_policy)
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{
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struct sugov_tunables *tunables;
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tunables = kzalloc(sizeof(*tunables), GFP_KERNEL);
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if (tunables) {
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gov_attr_set_init(&tunables->attr_set, &sg_policy->tunables_hook);
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if (!have_governor_per_policy())
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global_tunables = tunables;
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}
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return tunables;
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}
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static void sugov_tunables_free(struct sugov_tunables *tunables)
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{
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if (!have_governor_per_policy())
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global_tunables = NULL;
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kfree(tunables);
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}
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static int sugov_init(struct cpufreq_policy *policy)
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{
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struct sugov_policy *sg_policy;
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struct sugov_tunables *tunables;
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unsigned int lat;
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int ret = 0;
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/* State should be equivalent to EXIT */
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if (policy->governor_data)
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return -EBUSY;
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sg_policy = sugov_policy_alloc(policy);
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if (!sg_policy)
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return -ENOMEM;
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mutex_lock(&global_tunables_lock);
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if (global_tunables) {
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if (WARN_ON(have_governor_per_policy())) {
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ret = -EINVAL;
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goto free_sg_policy;
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}
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policy->governor_data = sg_policy;
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sg_policy->tunables = global_tunables;
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gov_attr_set_get(&global_tunables->attr_set, &sg_policy->tunables_hook);
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goto out;
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}
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tunables = sugov_tunables_alloc(sg_policy);
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if (!tunables) {
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ret = -ENOMEM;
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goto free_sg_policy;
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}
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tunables->rate_limit_us = LATENCY_MULTIPLIER;
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lat = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
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if (lat)
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tunables->rate_limit_us *= lat;
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policy->governor_data = sg_policy;
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sg_policy->tunables = tunables;
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ret = kobject_init_and_add(&tunables->attr_set.kobj, &sugov_tunables_ktype,
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get_governor_parent_kobj(policy), "%s",
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schedutil_gov.name);
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if (ret)
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goto fail;
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out:
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mutex_unlock(&global_tunables_lock);
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cpufreq_enable_fast_switch(policy);
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return 0;
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fail:
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policy->governor_data = NULL;
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sugov_tunables_free(tunables);
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free_sg_policy:
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mutex_unlock(&global_tunables_lock);
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sugov_policy_free(sg_policy);
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pr_err("initialization failed (error %d)\n", ret);
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return ret;
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}
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static void sugov_exit(struct cpufreq_policy *policy)
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{
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struct sugov_policy *sg_policy = policy->governor_data;
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struct sugov_tunables *tunables = sg_policy->tunables;
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unsigned int count;
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cpufreq_disable_fast_switch(policy);
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mutex_lock(&global_tunables_lock);
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count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);
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policy->governor_data = NULL;
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if (!count)
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sugov_tunables_free(tunables);
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mutex_unlock(&global_tunables_lock);
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sugov_policy_free(sg_policy);
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}
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static int sugov_start(struct cpufreq_policy *policy)
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{
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struct sugov_policy *sg_policy = policy->governor_data;
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unsigned int cpu;
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sg_policy->freq_update_delay_ns = sg_policy->tunables->rate_limit_us * NSEC_PER_USEC;
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sg_policy->last_freq_update_time = 0;
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sg_policy->next_freq = UINT_MAX;
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sg_policy->work_in_progress = false;
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sg_policy->need_freq_update = false;
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for_each_cpu(cpu, policy->cpus) {
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struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
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sg_cpu->sg_policy = sg_policy;
|
|
if (policy_is_shared(policy)) {
|
|
sg_cpu->util = 0;
|
|
sg_cpu->max = 0;
|
|
sg_cpu->flags = SCHED_CPUFREQ_RT;
|
|
sg_cpu->last_update = 0;
|
|
sg_cpu->cached_raw_freq = 0;
|
|
sg_cpu->iowait_boost = 0;
|
|
sg_cpu->iowait_boost_max = policy->cpuinfo.max_freq;
|
|
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 void 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);
|
|
}
|
|
|
|
static void 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);
|
|
cpufreq_policy_apply_limits(policy);
|
|
mutex_unlock(&sg_policy->work_lock);
|
|
}
|
|
|
|
sg_policy->need_freq_update = true;
|
|
}
|
|
|
|
static struct cpufreq_governor schedutil_gov = {
|
|
.name = "schedutil",
|
|
.owner = THIS_MODULE,
|
|
.init = sugov_init,
|
|
.exit = sugov_exit,
|
|
.start = sugov_start,
|
|
.stop = sugov_stop,
|
|
.limits = sugov_limits,
|
|
};
|
|
|
|
#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
|
|
struct cpufreq_governor *cpufreq_default_governor(void)
|
|
{
|
|
return &schedutil_gov;
|
|
}
|
|
#endif
|
|
|
|
static int __init sugov_register(void)
|
|
{
|
|
return cpufreq_register_governor(&schedutil_gov);
|
|
}
|
|
fs_initcall(sugov_register);
|