linux-kernel - [PATCH 70/70] cpufreq: interactive: Round up timer

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Date:	Tue, 27 Oct 2015 18:30:58 +0100
From:	Bálint Czobor <czoborbalint@...il.com>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	Junjie Wu <junjiew@...eaurora.org>,
	Bálint Czobor <czoborbalint@...il.com>
Subject: [PATCH 70/70] cpufreq: interactive: Round up timer_rate to match jiffy

From: Junjie Wu <junjiew@...eaurora.org>

Timers are scheduled in unit of jiffies. Round up timer_rate so that
it matches the actual sampling period.

Change-Id: I88386a5a448e40333f9a9b9f0cf72af58cb54656
Signed-off-by: Junjie Wu <junjiew@...eaurora.org>
Signed-off-by: Bálint Czobor <czoborbalint@...il.com>
---
 drivers/cpufreq/cpufreq_interactive.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index 95525b3..a2fc98a 100644
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -852,12 +852,18 @@ static ssize_t store_timer_rate(struct cpufreq_interactive_tunables *tunables,
 		const char *buf, size_t count)
 {
 	int ret;
-	unsigned long val;
+	unsigned long val, val_round;
 
 	ret = kstrtoul(buf, 0, &val);
 	if (ret < 0)
 		return ret;
-	tunables->timer_rate = val;
+
+	val_round = jiffies_to_usecs(usecs_to_jiffies(val));
+	if (val != val_round)
+		pr_warn("timer_rate not aligned to jiffy. Rounded up to %lu\n",
+			val_round);
+
+	tunables->timer_rate = val_round;
 	return count;
 }
 
-- 
1.7.9.5

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