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| author | Viresh Kumar <viresh.kumar@linaro.org> | 2019-02-01 11:45:45 +0530 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2019-02-01 11:52:11 +0100 |
| commit | 9795607dc41e7606e90e48bffe6927bee32cd336 (patch) | |
| tree | 5189380ea3c0ac3dfd6e39bce1dd92a09205c89c /drivers/cpufreq | |
| parent | 10b818211d04805da731087e596fc7c6ce199dea (diff) | |
| download | linux-9795607dc41e7606e90e48bffe6927bee32cd336.tar.bz2 | |
cpufreq: stats: Fix concurrency issues while resetting stats
It is possible for cpufreq_stats_clear_table() and
cpufreq_stats_record_transition() to get called concurrently and they
will try to update same variables simultaneously and may lead to
corruption of data.
Prevent that with the help of existing spinlock.
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 | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c index 941e63e3e652..e2db5581489a 100644 --- a/drivers/cpufreq/cpufreq_stats.c +++ b/drivers/cpufreq/cpufreq_stats.c @@ -31,20 +31,20 @@ static void cpufreq_stats_update(struct cpufreq_stats *stats) { unsigned long long cur_time = get_jiffies_64(); - spin_lock(&cpufreq_stats_lock); stats->time_in_state[stats->last_index] += cur_time - stats->last_time; stats->last_time = cur_time; - spin_unlock(&cpufreq_stats_lock); } static void cpufreq_stats_clear_table(struct cpufreq_stats *stats) { unsigned int count = stats->max_state; + spin_lock(&cpufreq_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); } static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf) @@ -62,7 +62,10 @@ 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); cpufreq_stats_update(stats); + spin_unlock(&cpufreq_stats_lock); + for (i = 0; i < stats->state_num; i++) { len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i], (unsigned long long) @@ -239,9 +242,11 @@ 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); 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); } |