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SubjectRe: [PATCH v2] cpufreq: stats: Use lock by stat to replace global spin lock
On 09-04-19, 16:43, Kyle Lin wrote:
> 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);
> }

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

--
viresh

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