[PATCH 5/7] cpufreq: Do not update related_cpus on every policy activation

From: Rafael J. Wysocki
Date: Mon Jul 27 2015 - 09:44:51 EST


From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

The related_cpus mask includes CPUs whose cpufreq_cpu_data per-CPU
pointers have been set to the given policy. Since those pointers
are only set at the policy creation time and unset when the policy
is deleted, the related_cpus should not be updated between those
two operations.

For this reason, avoid updating it whenever the first of the
"related" CPUs goes online.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
drivers/cpufreq/cpufreq.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

Index: linux-pm/drivers/cpufreq/cpufreq.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq.c
+++ linux-pm/drivers/cpufreq/cpufreq.c
@@ -1251,12 +1251,12 @@ static int cpufreq_add_dev(struct device

down_write(&policy->rwsem);

- /* related cpus should atleast have policy->cpus */
- cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
-
- /* Remember which CPUs have been present at the policy creation time. */
- if (!recover_policy)
+ if (!recover_policy) {
+ /* related_cpus should at least include policy->cpus. */
+ cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
+ /* Remember CPUs present at the policy creation time. */
cpumask_and(policy->real_cpus, policy->cpus, cpu_present_mask);
+ }

/*
* affected cpus must always be the one, which are online. We aren't

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