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[V2,14/14] cpufreq: stats: call cpufreq_stats_update() with locks held

Message ID 98184387b402a80ba58e9b727c4dacd95abdd8d4.1420177186.git.viresh.kumar@linaro.org
State New
Headers show

Commit Message

Viresh Kumar Jan. 2, 2015, 5:46 a.m. UTC 
cpufreq_stats_update() has only two callers, one of them is already taking locks
and other one don't.

To make locking efficient for cpufreq_stat_notifier_trans(), lets call
cpufreq_stats_update() from within locks. Also update show_time_in_state() to
call cpufreq_stats_update() after taking locks.

Reviewed-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/cpufreq/cpufreq_stats.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)
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Patch

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index 95867985ea02..f1b234a09f66 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -40,12 +40,10 @@  static int cpufreq_stats_update(struct cpufreq_stats *stat)
 {
 	unsigned long long cur_time = get_jiffies_64();
 
-	mutex_lock(&cpufreq_stats_lock);
 	if (stat->time_in_state)
 		stat->time_in_state[stat->last_index] +=
 			cur_time - stat->last_time;
 	stat->last_time = cur_time;
-	mutex_unlock(&cpufreq_stats_lock);
 	return 0;
 }
 
@@ -62,7 +60,10 @@  static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
 	ssize_t len = 0;
 	int i;
 
+	mutex_lock(&cpufreq_stats_lock);
 	cpufreq_stats_update(stat);
+	mutex_unlock(&cpufreq_stats_lock);
+
 	for (i = 0; i < stat->state_num; i++) {
 		len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
 			(unsigned long long)
@@ -303,9 +304,9 @@  static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
 	if (old_index == new_index)
 		return 0;
 
+	mutex_lock(&cpufreq_stats_lock);
 	cpufreq_stats_update(stat);
 
-	mutex_lock(&cpufreq_stats_lock);
 	stat->last_index = new_index;
 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 	stat->trans_table[old_index * stat->max_state + new_index]++;