linux-kernel - [PATCH v3 3/5] cpufreq: qcom-cpufreq-hw: Update offline CPUs per-cpu thermal pressure

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Message-Id: <20211103161020.26714-4-lukasz.luba@arm.com>
Date:   Wed,  3 Nov 2021 16:10:18 +0000
From:   Lukasz Luba <lukasz.luba@....com>
To:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Cc:     linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, lukasz.luba@....com,
        sudeep.holla@....com, will@...nel.org, catalin.marinas@....com,
        linux@...linux.org.uk, gregkh@...uxfoundation.org,
        rafael@...nel.org, viresh.kumar@...aro.org, amitk@...nel.org,
        daniel.lezcano@...aro.org, amit.kachhap@...il.com,
        thara.gopinath@...aro.org, bjorn.andersson@...aro.org,
        agross@...nel.org
Subject: [PATCH v3 3/5] cpufreq: qcom-cpufreq-hw: Update offline CPUs per-cpu thermal pressure

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 there is throttling
or throttling is removed.

Fixes: 275157b367f479 ("cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support")
Reviewed-by: Thara Gopinath <thara.gopinath@...aro.org>
Signed-off-by: Lukasz Luba <lukasz.luba@....com>
---
 drivers/cpufreq/qcom-cpufreq-hw.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
index a2be0df7e174..0138b2ec406d 100644
--- a/drivers/cpufreq/qcom-cpufreq-hw.c
+++ b/drivers/cpufreq/qcom-cpufreq-hw.c
@@ -304,7 +304,8 @@ static void qcom_lmh_dcvs_notify(struct qcom_cpufreq_data *data)
 	if (capacity > max_capacity)
 		capacity = max_capacity;
 
-	arch_set_thermal_pressure(policy->cpus, max_capacity - capacity);
+	arch_set_thermal_pressure(policy->related_cpus,
+				  max_capacity - capacity);
 
 	/*
 	 * In the unlikely case policy is unregistered do not enable
-- 
2.17.1