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thermal/cpufreq_cooling: Update offline CPUs per-cpu thermal_pressure

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The thermal pressure signal gives information to the scheduler about
reduced CPU capacity due to thermal. It is based on a value stored in
a per-cpu 'thermal_pressure' variable. The online CPUs will get the
new value there, while the offline won't. Unfortunately, when the CPU
is back online, the value read from per-cpu variable might be wrong
(stale data).  This might affect the scheduler decisions, since it
sees the CPU capacity differently than what is actually available.

Fix it by making sure that all online+offline CPUs would get the
proper value in their per-cpu variable when thermal framework sets
capping.

Fixes: f12e4f66ab ("thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping")
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20210614191030.22241-1-lukasz.luba@arm.com
This commit is contained in:
Lukasz Luba 2021-06-14 20:10:30 +01:00 committed by Peter Zijlstra
parent 83c5e9d573
commit 2ad8ccc17d
1 changed files with 1 additions and 1 deletions
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2
drivers/thermal/cpufreq_cooling.c
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@ -478,7 +478,7 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
ret = freq_qos_update_request(&cpufreq_cdev->qos_req, frequency);
if (ret >= 0) {
cpufreq_cdev->cpufreq_state = state;
cpus = cpufreq_cdev->policy->cpus;
cpus = cpufreq_cdev->policy->related_cpus;
max_capacity = arch_scale_cpu_capacity(cpumask_first(cpus));
capacity = frequency * max_capacity;
capacity /= cpufreq_cdev->policy->cpuinfo.max_freq;