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Subject[PATCH v2] cpufreq: stats: Use lock by stat to replace global spin lock
Date
Stats is updated by each policy, using the lock by stat can
reduce the contention.

Signed-off-by: Kyle Lin <linkyle0915@gmail.com>
---
Changes in v2:
- Drop the comment of the lock.

drivers/cpufreq/cpufreq_stats.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index e2db5581489a..08b192eb22c6 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -14,7 +14,6 @@
#include <linux/module.h>
#include <linux/slab.h>

-static DEFINE_SPINLOCK(cpufreq_stats_lock);

struct cpufreq_stats {
unsigned int total_trans;
@@ -23,6 +22,7 @@ struct cpufreq_stats {
unsigned int state_num;
unsigned int last_index;
u64 *time_in_state;
+ spinlock_t lock;
unsigned int *freq_table;
unsigned int *trans_table;
};
@@ -39,12 +39,12 @@ static void cpufreq_stats_clear_table(struct cpufreq_stats *stats)
{
unsigned int count = stats->max_state;

- spin_lock(&cpufreq_stats_lock);
+ spin_lock(&stats->lock);
memset(stats->time_in_state, 0, count * sizeof(u64));
memset(stats->trans_table, 0, count * count * sizeof(int));
stats->last_time = get_jiffies_64();
stats->total_trans = 0;
- spin_unlock(&cpufreq_stats_lock);
+ spin_unlock(&stats->lock);
}

static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
@@ -62,9 +62,9 @@ static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
if (policy->fast_switch_enabled)
return 0;

- spin_lock(&cpufreq_stats_lock);
+ spin_lock(&stats->lock);
cpufreq_stats_update(stats);
- spin_unlock(&cpufreq_stats_lock);
+ spin_unlock(&stats->lock);

for (i = 0; i < stats->state_num; i++) {
len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
@@ -211,6 +211,7 @@ void cpufreq_stats_create_table(struct cpufreq_policy *policy)
stats->state_num = i;
stats->last_time = get_jiffies_64();
stats->last_index = freq_table_get_index(stats, policy->cur);
+ spin_lock_init(&stats->lock);

policy->stats = stats;
ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
@@ -242,11 +243,11 @@ void cpufreq_stats_record_transition(struct cpufreq_policy *policy,
if (old_index == -1 || new_index == -1 || old_index == new_index)
return;

- spin_lock(&cpufreq_stats_lock);
+ spin_lock(&stats->lock);
cpufreq_stats_update(stats);

stats->last_index = new_index;
stats->trans_table[old_index * stats->max_state + new_index]++;
stats->total_trans++;
- spin_unlock(&cpufreq_stats_lock);
+ spin_unlock(&stats->lock);
}
--
2.21.0.392.gf8f6787159e-goog
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