diff options
| author | Viresh Kumar <viresh.kumar@linaro.org> | 2015-01-06 21:09:15 +0530 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2015-01-23 23:06:45 +0100 |
| commit | 490285c65e2398a533035dd9d75cb606a61ea39a (patch) | |
| tree | e18fa0f20423f9838e3bafe5e7f036fc4b75ae33 /drivers/cpufreq | |
| parent | e73476949c6d1e2edd04bbf7b5bae30afa370e33 (diff) | |
cpufreq: stats: drop unnecessary locking
There is no possibility of any race on updating last_index, trans_table or
total_trans as these are updated only by cpufreq_stat_notifier_trans() which
will be called sequentially.
The only place where locking is still relevant is: cpufreq_stats_update(), which
updates time_in_state and last_time. This can be called by two thread in
parallel, that may result in races.
The two threads being:
- sysfs read of time_in_state
- and frequency transition that calls cpufreq_stat_notifier_trans().
Remove locking from the first case mentioned above.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/cpufreq_stats.c | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c index c948086a332..5e370a30a96 100644 --- a/drivers/cpufreq/cpufreq_stats.c +++ b/drivers/cpufreq/cpufreq_stats.c @@ -207,12 +207,10 @@ static int __cpufreq_stats_create_table(struct cpufreq_policy *policy) cpufreq_for_each_valid_entry(pos, table) if (freq_table_get_index(stats, pos->frequency) == -1) stats->freq_table[i++] = pos->frequency; - stats->state_num = i; - spin_lock(&cpufreq_stats_lock); + stats->state_num = i; stats->last_time = get_jiffies_64(); stats->last_index = freq_table_get_index(stats, policy->cur); - spin_unlock(&cpufreq_stats_lock); policy->stats = stats; ret = sysfs_create_group(&policy->kobj, &stats_attr_group); @@ -294,13 +292,11 @@ static int cpufreq_stat_notifier_trans(struct notifier_block *nb, cpufreq_stats_update(stats); - spin_lock(&cpufreq_stats_lock); stats->last_index = new_index; #ifdef CONFIG_CPU_FREQ_STAT_DETAILS stats->trans_table[old_index * stats->max_state + new_index]++; #endif stats->total_trans++; - spin_unlock(&cpufreq_stats_lock); put_policy: cpufreq_cpu_put(policy); |