linux-kernel - [PATCH 1/2] cpufreq: schedutil: Don't restrict kthread to related

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Message-Id: <8dd297a6ed05ed3f6c33aeb3059e71a1d270c530.1502338812.git.viresh.kumar@linaro.org>
Date:   Thu, 10 Aug 2017 09:50:55 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Rafael Wysocki <rjw@...ysocki.net>, Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Viresh Kumar <viresh.kumar@...aro.org>, linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Juri Lelli <Juri.Lelli@....com>, joelaf@...gle.com,
        Pavan Kondeti <pkondeti@...eaurora.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] cpufreq: schedutil: Don't restrict kthread to related_cpus unnecessarily

Utilization update callbacks are now processed remotely, even on the
CPUs that don't share cpufreq policy with the target CPU (if
dvfs_possible_from_any_cpu flag is set).

But in non-fast switch paths, the frequency is changed only from one of
policy->related_cpus. This happens because the kthread which does the
actual update is bound to a subset of CPUs (i.e. related_cpus).

Allow frequency to be remotely updated as well (i.e. call
__cpufreq_driver_target()) if dvfs_possible_from_any_cpu flag is set.

Reported-by: Pavan Kondeti <pkondeti@...eaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 kernel/sched/cpufreq_schedutil.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 2e74c49776be..504d0752f8f2 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -487,7 +487,11 @@ static int sugov_kthread_create(struct sugov_policy *sg_policy)
 	}
 
 	sg_policy->thread = thread;
-	kthread_bind_mask(thread, policy->related_cpus);
+
+	/* Kthread is bound to all CPUs by default */
+	if (!policy->dvfs_possible_from_any_cpu)
+		kthread_bind_mask(thread, policy->related_cpus);
+
 	init_irq_work(&sg_policy->irq_work, sugov_irq_work);
 	mutex_init(&sg_policy->work_lock);
 
-- 
2.13.0.71.gd7076ec9c9cb