mirror of
https://github.com/torvalds/linux
synced 2024-09-06 18:01:05 +00:00
![Vincent Guittot](/assets/img/avatar_default.png)
Linus reported a ~50% performance regression on single-threaded workloads on his AMD Ryzen system, and bisected it to:9c0b4bb7f6
("sched/cpufreq: Rework schedutil governor performance estimation") When frequency invariance is not enabled, get_capacity_ref_freq(policy) is supposed to return the current frequency and the performance margin applied by map_util_perf(), enabling the utilization to go above the maximum compute capacity and to select a higher frequency than the current one. After the changes in9c0b4bb7f6
, the performance margin was applied earlier in the path to take into account utilization clampings and we couldn't get a utilization higher than the maximum compute capacity, and the CPU remained 'stuck' at lower frequencies. To fix this, we must use a frequency above the current frequency to get a chance to select a higher OPP when the current one becomes fully used. Apply the same margin and return a frequency 25% higher than the current one in order to switch to the next OPP before we fully use the CPU at the current one. [ mingo: Clarified the changelog. ] Fixes:9c0b4bb7f6
("sched/cpufreq: Rework schedutil governor performance estimation") Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Bisected-by: Linus Torvalds <torvalds@linux-foundation.org> Reported-by: Wyes Karny <wkarny@gmail.com> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Wyes Karny <wkarny@gmail.com> Link: https://lore.kernel.org/r/20240114183600.135316-1-vincent.guittot@linaro.org
906 lines
24 KiB
C
906 lines
24 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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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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#define IOWAIT_BOOST_MIN (SCHED_CAPACITY_SCALE / 8)
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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;
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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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unsigned int cached_raw_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 kthread_work work;
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struct mutex work_lock;
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struct kthread_worker worker;
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struct task_struct *thread;
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bool work_in_progress;
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bool limits_changed;
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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 cpu;
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bool iowait_boost_pending;
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unsigned int iowait_boost;
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u64 last_update;
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unsigned long util;
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unsigned long bw_min;
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/* The field below is for single-CPU policies only: */
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#ifdef CONFIG_NO_HZ_COMMON
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unsigned long saved_idle_calls;
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#endif
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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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/*
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* Since cpufreq_update_util() is called with rq->lock held for
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* the @target_cpu, our per-CPU data is fully serialized.
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*
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* However, drivers cannot in general deal with cross-CPU
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* requests, so while get_next_freq() will work, our
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* sugov_update_commit() call may not for the fast switching platforms.
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*
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* Hence stop here for remote requests if they aren't supported
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* by the hardware, as calculating the frequency is pointless if
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* we cannot in fact act on it.
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*
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* This is needed on the slow switching platforms too to prevent CPUs
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* going offline from leaving stale IRQ work items behind.
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*/
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if (!cpufreq_this_cpu_can_update(sg_policy->policy))
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return false;
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if (unlikely(sg_policy->limits_changed)) {
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sg_policy->limits_changed = false;
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sg_policy->need_freq_update = true;
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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 bool sugov_update_next_freq(struct sugov_policy *sg_policy, u64 time,
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unsigned int next_freq)
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{
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if (sg_policy->need_freq_update)
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sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS);
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else if (sg_policy->next_freq == next_freq)
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return false;
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sg_policy->next_freq = next_freq;
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sg_policy->last_freq_update_time = time;
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return true;
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}
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static void sugov_deferred_update(struct sugov_policy *sg_policy)
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{
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if (!sg_policy->work_in_progress) {
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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_capacity_ref_freq - get the reference frequency that has been used to
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* correlate frequency and compute capacity for a given cpufreq policy. We use
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* the CPU managing it for the arch_scale_freq_ref() call in the function.
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* @policy: the cpufreq policy of the CPU in question.
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*
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* Return: the reference CPU frequency to compute a capacity.
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*/
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static __always_inline
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unsigned long get_capacity_ref_freq(struct cpufreq_policy *policy)
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{
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unsigned int freq = arch_scale_freq_ref(policy->cpu);
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if (freq)
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return freq;
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if (arch_scale_freq_invariant())
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return policy->cpuinfo.max_freq;
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/*
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* Apply a 25% margin so that we select a higher frequency than
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* the current one before the CPU is fully busy:
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*/
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return policy->cur + (policy->cur >> 2);
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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_policy: schedutil policy 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_policy *sg_policy,
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unsigned long util, unsigned long max)
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{
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struct cpufreq_policy *policy = sg_policy->policy;
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unsigned int freq;
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freq = get_capacity_ref_freq(policy);
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freq = map_util_freq(util, freq, max);
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if (freq == sg_policy->cached_raw_freq && !sg_policy->need_freq_update)
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return sg_policy->next_freq;
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sg_policy->cached_raw_freq = freq;
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return cpufreq_driver_resolve_freq(policy, freq);
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}
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unsigned long sugov_effective_cpu_perf(int cpu, unsigned long actual,
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unsigned long min,
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unsigned long max)
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{
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/* Add dvfs headroom to actual utilization */
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actual = map_util_perf(actual);
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/* Actually we don't need to target the max performance */
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if (actual < max)
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max = actual;
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/*
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* Ensure at least minimum performance while providing more compute
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* capacity when possible.
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*/
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return max(min, max);
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}
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static void sugov_get_util(struct sugov_cpu *sg_cpu, unsigned long boost)
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{
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unsigned long min, max, util = cpu_util_cfs_boost(sg_cpu->cpu);
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util = effective_cpu_util(sg_cpu->cpu, util, &min, &max);
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util = max(util, boost);
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sg_cpu->bw_min = min;
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sg_cpu->util = sugov_effective_cpu_perf(sg_cpu->cpu, util, min, max);
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}
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/**
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* sugov_iowait_reset() - Reset the IO boost status of a CPU.
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* @sg_cpu: the sugov data for the CPU to boost
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* @time: the update time from the caller
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* @set_iowait_boost: true if an IO boost has been requested
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*
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* The IO wait boost of a task is disabled after a tick since the last update
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* of a CPU. If a new IO wait boost is requested after more then a tick, then
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* we enable the boost starting from IOWAIT_BOOST_MIN, which improves energy
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* efficiency by ignoring sporadic wakeups from IO.
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*/
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static bool sugov_iowait_reset(struct sugov_cpu *sg_cpu, u64 time,
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bool set_iowait_boost)
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{
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s64 delta_ns = time - sg_cpu->last_update;
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/* Reset boost only if a tick has elapsed since last request */
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if (delta_ns <= TICK_NSEC)
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return false;
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sg_cpu->iowait_boost = set_iowait_boost ? IOWAIT_BOOST_MIN : 0;
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sg_cpu->iowait_boost_pending = set_iowait_boost;
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return true;
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}
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/**
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* sugov_iowait_boost() - Updates the IO boost status of a CPU.
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* @sg_cpu: the sugov data for the CPU to boost
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* @time: the update time from the caller
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* @flags: SCHED_CPUFREQ_IOWAIT if the task is waking up after an IO wait
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*
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* Each time a task wakes up after an IO operation, the CPU utilization can be
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* boosted to a certain utilization which doubles at each "frequent and
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* successive" wakeup from IO, ranging from IOWAIT_BOOST_MIN to the utilization
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* of the maximum OPP.
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*
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* To keep doubling, an IO boost has to be requested at least once per tick,
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* otherwise we restart from the utilization of the minimum OPP.
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*/
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static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
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unsigned int flags)
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{
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bool set_iowait_boost = flags & SCHED_CPUFREQ_IOWAIT;
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/* Reset boost if the CPU appears to have been idle enough */
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if (sg_cpu->iowait_boost &&
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sugov_iowait_reset(sg_cpu, time, set_iowait_boost))
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return;
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/* Boost only tasks waking up after IO */
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if (!set_iowait_boost)
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return;
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/* Ensure boost doubles only one time at each request */
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if (sg_cpu->iowait_boost_pending)
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return;
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sg_cpu->iowait_boost_pending = true;
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/* Double the boost at each request */
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if (sg_cpu->iowait_boost) {
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sg_cpu->iowait_boost =
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min_t(unsigned int, sg_cpu->iowait_boost << 1, SCHED_CAPACITY_SCALE);
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return;
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}
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/* First wakeup after IO: start with minimum boost */
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sg_cpu->iowait_boost = IOWAIT_BOOST_MIN;
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}
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/**
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* sugov_iowait_apply() - Apply the IO boost to a CPU.
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* @sg_cpu: the sugov data for the cpu to boost
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* @time: the update time from the caller
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* @max_cap: the max CPU capacity
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*
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* A CPU running a task which woken up after an IO operation can have its
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* utilization boosted to speed up the completion of those IO operations.
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* The IO boost value is increased each time a task wakes up from IO, in
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* sugov_iowait_apply(), and it's instead decreased by this function,
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* each time an increase has not been requested (!iowait_boost_pending).
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*
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* A CPU which also appears to have been idle for at least one tick has also
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* its IO boost utilization reset.
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*
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* This mechanism is designed to boost high frequently IO waiting tasks, while
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* being more conservative on tasks which does sporadic IO operations.
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*/
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static unsigned long sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time,
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unsigned long max_cap)
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{
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/* No boost currently required */
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if (!sg_cpu->iowait_boost)
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return 0;
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/* Reset boost if the CPU appears to have been idle enough */
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if (sugov_iowait_reset(sg_cpu, time, false))
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return 0;
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if (!sg_cpu->iowait_boost_pending) {
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/*
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* No boost pending; reduce the boost value.
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*/
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sg_cpu->iowait_boost >>= 1;
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if (sg_cpu->iowait_boost < IOWAIT_BOOST_MIN) {
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sg_cpu->iowait_boost = 0;
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return 0;
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}
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}
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sg_cpu->iowait_boost_pending = false;
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/*
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* sg_cpu->util is already in capacity scale; convert iowait_boost
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* into the same scale so we can compare.
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*/
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return (sg_cpu->iowait_boost * max_cap) >> SCHED_CAPACITY_SHIFT;
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}
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#ifdef CONFIG_NO_HZ_COMMON
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static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu)
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{
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unsigned long idle_calls = tick_nohz_get_idle_calls_cpu(sg_cpu->cpu);
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bool ret = idle_calls == sg_cpu->saved_idle_calls;
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sg_cpu->saved_idle_calls = idle_calls;
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return ret;
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}
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#else
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static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
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#endif /* CONFIG_NO_HZ_COMMON */
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/*
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* Make sugov_should_update_freq() ignore the rate limit when DL
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* has increased the utilization.
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*/
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static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu)
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{
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if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_min)
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sg_cpu->sg_policy->limits_changed = true;
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}
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static inline bool sugov_update_single_common(struct sugov_cpu *sg_cpu,
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u64 time, unsigned long max_cap,
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unsigned int flags)
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{
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unsigned long boost;
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sugov_iowait_boost(sg_cpu, time, flags);
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sg_cpu->last_update = time;
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ignore_dl_rate_limit(sg_cpu);
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if (!sugov_should_update_freq(sg_cpu->sg_policy, time))
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return false;
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boost = sugov_iowait_apply(sg_cpu, time, max_cap);
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sugov_get_util(sg_cpu, boost);
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return true;
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}
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static void sugov_update_single_freq(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 int cached_freq = sg_policy->cached_raw_freq;
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unsigned long max_cap;
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unsigned int next_f;
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max_cap = arch_scale_cpu_capacity(sg_cpu->cpu);
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if (!sugov_update_single_common(sg_cpu, time, max_cap, flags))
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return;
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next_f = get_next_freq(sg_policy, sg_cpu->util, max_cap);
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/*
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* Do not reduce the frequency if the CPU has not been idle
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* recently, as the reduction is likely to be premature then.
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*
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* Except when the rq is capped by uclamp_max.
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*/
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if (!uclamp_rq_is_capped(cpu_rq(sg_cpu->cpu)) &&
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sugov_cpu_is_busy(sg_cpu) && next_f < sg_policy->next_freq &&
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!sg_policy->need_freq_update) {
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next_f = sg_policy->next_freq;
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/* Restore cached freq as next_freq has changed */
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sg_policy->cached_raw_freq = cached_freq;
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}
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if (!sugov_update_next_freq(sg_policy, time, next_f))
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return;
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/*
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* This code runs under rq->lock for the target CPU, so it won't run
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* concurrently on two different CPUs for the same target and it is not
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* necessary to acquire the lock in the fast switch case.
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*/
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if (sg_policy->policy->fast_switch_enabled) {
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cpufreq_driver_fast_switch(sg_policy->policy, next_f);
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} else {
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raw_spin_lock(&sg_policy->update_lock);
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sugov_deferred_update(sg_policy);
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raw_spin_unlock(&sg_policy->update_lock);
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}
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}
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static void sugov_update_single_perf(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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unsigned long prev_util = sg_cpu->util;
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unsigned long max_cap;
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/*
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* Fall back to the "frequency" path if frequency invariance is not
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* supported, because the direct mapping between the utilization and
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* the performance levels depends on the frequency invariance.
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*/
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if (!arch_scale_freq_invariant()) {
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sugov_update_single_freq(hook, time, flags);
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return;
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}
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max_cap = arch_scale_cpu_capacity(sg_cpu->cpu);
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if (!sugov_update_single_common(sg_cpu, time, max_cap, flags))
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return;
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/*
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* Do not reduce the target performance level if the CPU has not been
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* idle recently, as the reduction is likely to be premature then.
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*
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* Except when the rq is capped by uclamp_max.
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*/
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if (!uclamp_rq_is_capped(cpu_rq(sg_cpu->cpu)) &&
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sugov_cpu_is_busy(sg_cpu) && sg_cpu->util < prev_util)
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sg_cpu->util = prev_util;
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cpufreq_driver_adjust_perf(sg_cpu->cpu, sg_cpu->bw_min,
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sg_cpu->util, max_cap);
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sg_cpu->sg_policy->last_freq_update_time = time;
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}
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static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
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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 long util = 0, max_cap;
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unsigned int j;
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max_cap = arch_scale_cpu_capacity(sg_cpu->cpu);
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for_each_cpu(j, policy->cpus) {
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struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
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unsigned long boost;
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boost = sugov_iowait_apply(j_sg_cpu, time, max_cap);
|
|
sugov_get_util(j_sg_cpu, boost);
|
|
|
|
util = max(j_sg_cpu->util, util);
|
|
}
|
|
|
|
return get_next_freq(sg_policy, util, max_cap);
|
|
}
|
|
|
|
static void
|
|
sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int flags)
|
|
{
|
|
struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
|
|
struct sugov_policy *sg_policy = sg_cpu->sg_policy;
|
|
unsigned int next_f;
|
|
|
|
raw_spin_lock(&sg_policy->update_lock);
|
|
|
|
sugov_iowait_boost(sg_cpu, time, flags);
|
|
sg_cpu->last_update = time;
|
|
|
|
ignore_dl_rate_limit(sg_cpu);
|
|
|
|
if (sugov_should_update_freq(sg_policy, time)) {
|
|
next_f = sugov_next_freq_shared(sg_cpu, time);
|
|
|
|
if (!sugov_update_next_freq(sg_policy, time, next_f))
|
|
goto unlock;
|
|
|
|
if (sg_policy->policy->fast_switch_enabled)
|
|
cpufreq_driver_fast_switch(sg_policy->policy, next_f);
|
|
else
|
|
sugov_deferred_update(sg_policy);
|
|
}
|
|
unlock:
|
|
raw_spin_unlock(&sg_policy->update_lock);
|
|
}
|
|
|
|
static void sugov_work(struct kthread_work *work)
|
|
{
|
|
struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work);
|
|
unsigned int freq;
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* Hold sg_policy->update_lock shortly to handle the case where:
|
|
* in case sg_policy->next_freq is read here, and then updated by
|
|
* sugov_deferred_update() just before work_in_progress is set to false
|
|
* here, we may miss queueing the new update.
|
|
*
|
|
* Note: If a work was queued after the update_lock is released,
|
|
* sugov_work() will just be called again by kthread_work code; and the
|
|
* request will be proceed before the sugov thread sleeps.
|
|
*/
|
|
raw_spin_lock_irqsave(&sg_policy->update_lock, flags);
|
|
freq = sg_policy->next_freq;
|
|
sg_policy->work_in_progress = false;
|
|
raw_spin_unlock_irqrestore(&sg_policy->update_lock, flags);
|
|
|
|
mutex_lock(&sg_policy->work_lock);
|
|
__cpufreq_driver_target(sg_policy->policy, freq, CPUFREQ_RELATION_L);
|
|
mutex_unlock(&sg_policy->work_lock);
|
|
}
|
|
|
|
static void sugov_irq_work(struct irq_work *irq_work)
|
|
{
|
|
struct sugov_policy *sg_policy;
|
|
|
|
sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
|
|
|
|
kthread_queue_work(&sg_policy->worker, &sg_policy->work);
|
|
}
|
|
|
|
/************************** sysfs interface ************************/
|
|
|
|
static struct sugov_tunables *global_tunables;
|
|
static DEFINE_MUTEX(global_tunables_lock);
|
|
|
|
static inline struct sugov_tunables *to_sugov_tunables(struct gov_attr_set *attr_set)
|
|
{
|
|
return container_of(attr_set, struct sugov_tunables, attr_set);
|
|
}
|
|
|
|
static ssize_t rate_limit_us_show(struct gov_attr_set *attr_set, char *buf)
|
|
{
|
|
struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
|
|
|
|
return sprintf(buf, "%u\n", tunables->rate_limit_us);
|
|
}
|
|
|
|
static ssize_t
|
|
rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf, size_t count)
|
|
{
|
|
struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
|
|
struct sugov_policy *sg_policy;
|
|
unsigned int rate_limit_us;
|
|
|
|
if (kstrtouint(buf, 10, &rate_limit_us))
|
|
return -EINVAL;
|
|
|
|
tunables->rate_limit_us = rate_limit_us;
|
|
|
|
list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook)
|
|
sg_policy->freq_update_delay_ns = rate_limit_us * NSEC_PER_USEC;
|
|
|
|
return count;
|
|
}
|
|
|
|
static struct governor_attr rate_limit_us = __ATTR_RW(rate_limit_us);
|
|
|
|
static struct attribute *sugov_attrs[] = {
|
|
&rate_limit_us.attr,
|
|
NULL
|
|
};
|
|
ATTRIBUTE_GROUPS(sugov);
|
|
|
|
static void sugov_tunables_free(struct kobject *kobj)
|
|
{
|
|
struct gov_attr_set *attr_set = to_gov_attr_set(kobj);
|
|
|
|
kfree(to_sugov_tunables(attr_set));
|
|
}
|
|
|
|
static const struct kobj_type sugov_tunables_ktype = {
|
|
.default_groups = sugov_groups,
|
|
.sysfs_ops = &governor_sysfs_ops,
|
|
.release = &sugov_tunables_free,
|
|
};
|
|
|
|
/********************** cpufreq governor interface *********************/
|
|
|
|
#ifdef CONFIG_ENERGY_MODEL
|
|
static void rebuild_sd_workfn(struct work_struct *work)
|
|
{
|
|
rebuild_sched_domains_energy();
|
|
}
|
|
|
|
static DECLARE_WORK(rebuild_sd_work, rebuild_sd_workfn);
|
|
|
|
/*
|
|
* EAS shouldn't be attempted without sugov, so rebuild the sched_domains
|
|
* on governor changes to make sure the scheduler knows about it.
|
|
*/
|
|
static void sugov_eas_rebuild_sd(void)
|
|
{
|
|
/*
|
|
* When called from the cpufreq_register_driver() path, the
|
|
* cpu_hotplug_lock is already held, so use a work item to
|
|
* avoid nested locking in rebuild_sched_domains().
|
|
*/
|
|
schedule_work(&rebuild_sd_work);
|
|
}
|
|
#else
|
|
static inline void sugov_eas_rebuild_sd(void) { };
|
|
#endif
|
|
|
|
struct cpufreq_governor schedutil_gov;
|
|
|
|
static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy)
|
|
{
|
|
struct sugov_policy *sg_policy;
|
|
|
|
sg_policy = kzalloc(sizeof(*sg_policy), GFP_KERNEL);
|
|
if (!sg_policy)
|
|
return NULL;
|
|
|
|
sg_policy->policy = policy;
|
|
raw_spin_lock_init(&sg_policy->update_lock);
|
|
return sg_policy;
|
|
}
|
|
|
|
static void sugov_policy_free(struct sugov_policy *sg_policy)
|
|
{
|
|
kfree(sg_policy);
|
|
}
|
|
|
|
static int sugov_kthread_create(struct sugov_policy *sg_policy)
|
|
{
|
|
struct task_struct *thread;
|
|
struct sched_attr attr = {
|
|
.size = sizeof(struct sched_attr),
|
|
.sched_policy = SCHED_DEADLINE,
|
|
.sched_flags = SCHED_FLAG_SUGOV,
|
|
.sched_nice = 0,
|
|
.sched_priority = 0,
|
|
/*
|
|
* Fake (unused) bandwidth; workaround to "fix"
|
|
* priority inheritance.
|
|
*/
|
|
.sched_runtime = 1000000,
|
|
.sched_deadline = 10000000,
|
|
.sched_period = 10000000,
|
|
};
|
|
struct cpufreq_policy *policy = sg_policy->policy;
|
|
int ret;
|
|
|
|
/* kthread only required for slow path */
|
|
if (policy->fast_switch_enabled)
|
|
return 0;
|
|
|
|
kthread_init_work(&sg_policy->work, sugov_work);
|
|
kthread_init_worker(&sg_policy->worker);
|
|
thread = kthread_create(kthread_worker_fn, &sg_policy->worker,
|
|
"sugov:%d",
|
|
cpumask_first(policy->related_cpus));
|
|
if (IS_ERR(thread)) {
|
|
pr_err("failed to create sugov thread: %ld\n", PTR_ERR(thread));
|
|
return PTR_ERR(thread);
|
|
}
|
|
|
|
ret = sched_setattr_nocheck(thread, &attr);
|
|
if (ret) {
|
|
kthread_stop(thread);
|
|
pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
|
|
return ret;
|
|
}
|
|
|
|
sg_policy->thread = thread;
|
|
kthread_bind_mask(thread, policy->related_cpus);
|
|
init_irq_work(&sg_policy->irq_work, sugov_irq_work);
|
|
mutex_init(&sg_policy->work_lock);
|
|
|
|
wake_up_process(thread);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void sugov_kthread_stop(struct sugov_policy *sg_policy)
|
|
{
|
|
/* kthread only required for slow path */
|
|
if (sg_policy->policy->fast_switch_enabled)
|
|
return;
|
|
|
|
kthread_flush_worker(&sg_policy->worker);
|
|
kthread_stop(sg_policy->thread);
|
|
mutex_destroy(&sg_policy->work_lock);
|
|
}
|
|
|
|
static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_policy)
|
|
{
|
|
struct sugov_tunables *tunables;
|
|
|
|
tunables = kzalloc(sizeof(*tunables), GFP_KERNEL);
|
|
if (tunables) {
|
|
gov_attr_set_init(&tunables->attr_set, &sg_policy->tunables_hook);
|
|
if (!have_governor_per_policy())
|
|
global_tunables = tunables;
|
|
}
|
|
return tunables;
|
|
}
|
|
|
|
static void sugov_clear_global_tunables(void)
|
|
{
|
|
if (!have_governor_per_policy())
|
|
global_tunables = NULL;
|
|
}
|
|
|
|
static int sugov_init(struct cpufreq_policy *policy)
|
|
{
|
|
struct sugov_policy *sg_policy;
|
|
struct sugov_tunables *tunables;
|
|
int ret = 0;
|
|
|
|
/* State should be equivalent to EXIT */
|
|
if (policy->governor_data)
|
|
return -EBUSY;
|
|
|
|
cpufreq_enable_fast_switch(policy);
|
|
|
|
sg_policy = sugov_policy_alloc(policy);
|
|
if (!sg_policy) {
|
|
ret = -ENOMEM;
|
|
goto disable_fast_switch;
|
|
}
|
|
|
|
ret = sugov_kthread_create(sg_policy);
|
|
if (ret)
|
|
goto free_sg_policy;
|
|
|
|
mutex_lock(&global_tunables_lock);
|
|
|
|
if (global_tunables) {
|
|
if (WARN_ON(have_governor_per_policy())) {
|
|
ret = -EINVAL;
|
|
goto stop_kthread;
|
|
}
|
|
policy->governor_data = sg_policy;
|
|
sg_policy->tunables = global_tunables;
|
|
|
|
gov_attr_set_get(&global_tunables->attr_set, &sg_policy->tunables_hook);
|
|
goto out;
|
|
}
|
|
|
|
tunables = sugov_tunables_alloc(sg_policy);
|
|
if (!tunables) {
|
|
ret = -ENOMEM;
|
|
goto stop_kthread;
|
|
}
|
|
|
|
tunables->rate_limit_us = cpufreq_policy_transition_delay_us(policy);
|
|
|
|
policy->governor_data = sg_policy;
|
|
sg_policy->tunables = tunables;
|
|
|
|
ret = kobject_init_and_add(&tunables->attr_set.kobj, &sugov_tunables_ktype,
|
|
get_governor_parent_kobj(policy), "%s",
|
|
schedutil_gov.name);
|
|
if (ret)
|
|
goto fail;
|
|
|
|
sugov_eas_rebuild_sd();
|
|
|
|
out:
|
|
mutex_unlock(&global_tunables_lock);
|
|
return 0;
|
|
|
|
fail:
|
|
kobject_put(&tunables->attr_set.kobj);
|
|
policy->governor_data = NULL;
|
|
sugov_clear_global_tunables();
|
|
|
|
stop_kthread:
|
|
sugov_kthread_stop(sg_policy);
|
|
mutex_unlock(&global_tunables_lock);
|
|
|
|
free_sg_policy:
|
|
sugov_policy_free(sg_policy);
|
|
|
|
disable_fast_switch:
|
|
cpufreq_disable_fast_switch(policy);
|
|
|
|
pr_err("initialization failed (error %d)\n", ret);
|
|
return ret;
|
|
}
|
|
|
|
static void sugov_exit(struct cpufreq_policy *policy)
|
|
{
|
|
struct sugov_policy *sg_policy = policy->governor_data;
|
|
struct sugov_tunables *tunables = sg_policy->tunables;
|
|
unsigned int count;
|
|
|
|
mutex_lock(&global_tunables_lock);
|
|
|
|
count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);
|
|
policy->governor_data = NULL;
|
|
if (!count)
|
|
sugov_clear_global_tunables();
|
|
|
|
mutex_unlock(&global_tunables_lock);
|
|
|
|
sugov_kthread_stop(sg_policy);
|
|
sugov_policy_free(sg_policy);
|
|
cpufreq_disable_fast_switch(policy);
|
|
|
|
sugov_eas_rebuild_sd();
|
|
}
|
|
|
|
static int sugov_start(struct cpufreq_policy *policy)
|
|
{
|
|
struct sugov_policy *sg_policy = policy->governor_data;
|
|
void (*uu)(struct update_util_data *data, u64 time, unsigned int flags);
|
|
unsigned int cpu;
|
|
|
|
sg_policy->freq_update_delay_ns = sg_policy->tunables->rate_limit_us * NSEC_PER_USEC;
|
|
sg_policy->last_freq_update_time = 0;
|
|
sg_policy->next_freq = 0;
|
|
sg_policy->work_in_progress = false;
|
|
sg_policy->limits_changed = false;
|
|
sg_policy->cached_raw_freq = 0;
|
|
|
|
sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS);
|
|
|
|
if (policy_is_shared(policy))
|
|
uu = sugov_update_shared;
|
|
else if (policy->fast_switch_enabled && cpufreq_driver_has_adjust_perf())
|
|
uu = sugov_update_single_perf;
|
|
else
|
|
uu = sugov_update_single_freq;
|
|
|
|
for_each_cpu(cpu, policy->cpus) {
|
|
struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
|
|
|
|
memset(sg_cpu, 0, sizeof(*sg_cpu));
|
|
sg_cpu->cpu = cpu;
|
|
sg_cpu->sg_policy = sg_policy;
|
|
cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util, uu);
|
|
}
|
|
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_rcu();
|
|
|
|
if (!policy->fast_switch_enabled) {
|
|
irq_work_sync(&sg_policy->irq_work);
|
|
kthread_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->limits_changed = true;
|
|
}
|
|
|
|
struct cpufreq_governor schedutil_gov = {
|
|
.name = "schedutil",
|
|
.owner = THIS_MODULE,
|
|
.flags = CPUFREQ_GOV_DYNAMIC_SWITCHING,
|
|
.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
|
|
|
|
cpufreq_governor_init(schedutil_gov);
|