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[5.10,099/593] thermal/cpufreq_cooling: Update offline CPUs per-cpu thermal_pressure

Message ID 20210712060854.110003059@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman July 12, 2021, 6:04 a.m. UTC 
From: Lukasz Luba <lukasz.luba@arm.com>

[ Upstream commit 2ad8ccc17d1e4270cf65a3f2a07a7534aa23e3fb ]

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: f12e4f66ab6a3 ("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
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/thermal/cpufreq_cooling.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c
index 3f6a69ccc173..6e1d6a31ee4f 100644
--- a/drivers/thermal/cpufreq_cooling.c
+++ b/drivers/thermal/cpufreq_cooling.c
@@ -443,7 +443,7 @@  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;