linux-kernel - [PATCH V2 6/9] cpufreq: ondemand: queue work for policy->cpus together

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Message-Id: <d2760eca0b3fd5e427d004120bdb82c1aed215ca.1437999691.git.viresh.kumar@linaro.org>
Date:	Mon, 27 Jul 2015 17:58:11 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Rafael Wysocki <rjw@...ysocki.net>
Cc:	linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
	preeti.lkml@...il.com, Viresh Kumar <viresh.kumar@...aro.org>,
	linux-kernel@...r.kernel.org (open list)
Subject: [PATCH V2 6/9] cpufreq: ondemand: queue work for policy->cpus together

Currently update_sampling_rate() runs over each online CPU and
cancels/queues work on it. Its very inefficient for the case where a
single policy manages multiple CPUs, as they can be processed together.

Also drop the unnecessary cancel_delayed_work_sync() as we are doing a
mod_delayed_work_on() in gov_queue_work(), which will take care of
pending works for us.

Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 drivers/cpufreq/cpufreq_ondemand.c | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index f1551fc7b4fd..a6f579e40ce2 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -247,40 +247,45 @@ static void update_sampling_rate(struct dbs_data *dbs_data,
 		unsigned int new_rate)
 {
 	struct od_dbs_tuners *od_tuners = dbs_data->tuners;
+	struct cpufreq_policy *policy;
+	struct od_cpu_dbs_info_s *dbs_info;
+	unsigned long next_sampling, appointed_at;
+	struct cpumask cpumask;
 	int cpu;
 
+	cpumask_copy(&cpumask, cpu_online_mask);
+
 	od_tuners->sampling_rate = new_rate = max(new_rate,
 			dbs_data->min_sampling_rate);
 
-	for_each_online_cpu(cpu) {
-		struct cpufreq_policy *policy;
-		struct od_cpu_dbs_info_s *dbs_info;
-		unsigned long next_sampling, appointed_at;
-
+	for_each_cpu(cpu, &cpumask) {
 		policy = cpufreq_cpu_get(cpu);
 		if (!policy)
 			continue;
+
+		/* clear all CPUs of this policy */
+		cpumask_andnot(&cpumask, &cpumask, policy->cpus);
+
 		if (policy->governor != &cpufreq_gov_ondemand) {
 			cpufreq_cpu_put(policy);
 			continue;
 		}
+
 		dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
 		cpufreq_cpu_put(policy);
 
-		if (!delayed_work_pending(&dbs_info->cdbs.dwork))
+		/* Make sure the work is not canceled on policy->cpus */
+		if (!dbs_info->cdbs.shared->policy)
 			continue;
 
 		next_sampling = jiffies + usecs_to_jiffies(new_rate);
 		appointed_at = dbs_info->cdbs.dwork.timer.expires;
 
-		if (time_before(next_sampling, appointed_at)) {
-			cancel_delayed_work_sync(&dbs_info->cdbs.dwork);
-
-			gov_queue_work(dbs_data, policy,
-				       usecs_to_jiffies(new_rate),
-				       cpumask_of(cpu));
+		if (!time_before(next_sampling, appointed_at))
+			continue;
 
-		}
+		gov_queue_work(dbs_data, policy, usecs_to_jiffies(new_rate),
+			       policy->cpus);
 	}
 }
 
-- 
2.4.0

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