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 --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;