On Wed, Feb 24, 2021 at 6:44 AM Yue Hu <zbest...@gmail.com> wrote:
>
> From: Yue Hu <huy...@yulong.com>
>
> Note that sugov_update_next_freq() may return false, that means the
> caller sugov_fast_switch() will do nothing except fast switch check.
>
> Similarly, sugov_deferred_update() also has unnecessary operations
> of raw_spin_{lock,unlock} in sugov_update_single_freq() for that case.
>
> So, let's call sugov_update_next_freq() before the fast switch check
> to avoid unnecessary behaviors above. Update the related interface
> definitions accordingly.
>
> Signed-off-by: Yue Hu <huy...@yulong.com>
> ---
> kernel/sched/cpufreq_schedutil.c | 28 ++++++++++++++--------------
> 1 file changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/kernel/sched/cpufreq_schedutil.c
> b/kernel/sched/cpufreq_schedutil.c
> index 41e498b..d23e5be 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -114,19 +114,13 @@ static bool sugov_update_next_freq(struct sugov_policy
> *sg_policy, u64 time,
> return true;
> }
>
> -static void sugov_fast_switch(struct sugov_policy *sg_policy, u64 time,
> - unsigned int next_freq)
> +static void sugov_fast_switch(struct sugov_policy *sg_policy, unsigned int
> next_freq)
> {
> - if (sugov_update_next_freq(sg_policy, time, next_freq))
> - cpufreq_driver_fast_switch(sg_policy->policy, next_freq);
> + cpufreq_driver_fast_switch(sg_policy->policy, next_freq);
> }
>
> -static void sugov_deferred_update(struct sugov_policy *sg_policy, u64 time,
> - unsigned int next_freq)
> +static void sugov_deferred_update(struct sugov_policy *sg_policy)
> {
> - if (!sugov_update_next_freq(sg_policy, time, next_freq))
> - return;
> -
> if (!sg_policy->work_in_progress) {
> sg_policy->work_in_progress = true;
> irq_work_queue(&sg_policy->irq_work);
> @@ -368,16 +362,19 @@ static void sugov_update_single_freq(struct
> update_util_data *hook, u64 time,
> sg_policy->cached_raw_freq = cached_freq;
> }
>
> + if (!sugov_update_next_freq(sg_policy, time, next_f))
> + return;
> +
> /*
> * This code runs under rq->lock for the target CPU, so it won't run
> * concurrently on two different CPUs for the same target and it is
> not
> * necessary to acquire the lock in the fast switch case.
> */
> if (sg_policy->policy->fast_switch_enabled) {
> - sugov_fast_switch(sg_policy, time, next_f);
> + sugov_fast_switch(sg_policy, next_f);
> } else {
> raw_spin_lock(&sg_policy->update_lock);
> - sugov_deferred_update(sg_policy, time, next_f);
> + sugov_deferred_update(sg_policy);
> raw_spin_unlock(&sg_policy->update_lock);
> }
> }
> @@ -456,12 +453,15 @@ static unsigned int sugov_next_freq_shared(struct
> sugov_cpu *sg_cpu, u64 time)
> if (sugov_should_update_freq(sg_policy, time)) {
> next_f = sugov_next_freq_shared(sg_cpu, time);
>
> + if (!sugov_update_next_freq(sg_policy, time, next_f))
> + goto unlock;
> +
> if (sg_policy->policy->fast_switch_enabled)
> - sugov_fast_switch(sg_policy, time, next_f);
> + sugov_fast_switch(sg_policy, next_f);
> else
> - sugov_deferred_update(sg_policy, time, next_f);
> + sugov_deferred_update(sg_policy);
> }
> -
> +unlock:
> raw_spin_unlock(&sg_policy->update_lock);
> }
>
> --
Applied as 5.13 material, thanks!
