On 02-03-16, 03:04, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > > 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.wyso...@intel.com> > --- > > Supersedes https://patchwork.kernel.org/patch/8443191/
Acked-by: Viresh Kumar <viresh.ku...@linaro.org> -- viresh
