diff options
author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-03-04 05:58:22 +0300 |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-03-09 17:07:58 +0300 |
commit | 08f511fd41c3afe303eb9b41bff0570f7c1b6937 (patch) | |
tree | 719b4b878711f8c4312fccb9d479151a817fcbaf /drivers/cpufreq/cpufreq_governor.c | |
parent | e6f036571e1f65021a442ec7aad087a6a239ecfb (diff) |
cpufreq: Reduce cpufreq_update_util() overhead a bit
Use the observation that cpufreq_update_util() is only called
by the scheduler with rq->lock held, so the callers of
cpufreq_set_update_util_data() can use synchronize_sched()
instead of synchronize_rcu() to wait for cpufreq_update_util()
to complete. Moreover, if they are updated to do that,
rcu_read_(un)lock() calls in cpufreq_update_util() might be
replaced with rcu_read_(un)lock_sched(), respectively, but
those aren't really necessary, because the scheduler calls
that function from RCU-sched read-side critical sections
already.
In addition to that, if cpufreq_set_update_util_data() checks
the func field in the struct update_util_data before setting
the per-CPU pointer to it, the data->func check may be dropped
from cpufreq_update_util() as well.
Make the above changes to reduce the overhead from
cpufreq_update_util() in the scheduler paths invoking it
and to make the cleanup after removing its callbacks less
heavy-weight somewhat.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Diffstat (limited to 'drivers/cpufreq/cpufreq_governor.c')
-rw-r--r-- | drivers/cpufreq/cpufreq_governor.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c index 70079e21fa2d..db46190bb246 100644 --- a/drivers/cpufreq/cpufreq_governor.c +++ b/drivers/cpufreq/cpufreq_governor.c @@ -280,7 +280,7 @@ static inline void gov_clear_update_util(struct cpufreq_policy *policy) for_each_cpu(i, policy->cpus) cpufreq_set_update_util_data(i, NULL); - synchronize_rcu(); + synchronize_sched(); } static void gov_cancel_work(struct cpufreq_policy *policy) |