cpufreq: schedutil: Call sugov_update_next_freq() before check to fast_switch_enabled

Message ID 20210224054232.1222-1-zbestahu@gmail.com
State New
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  • cpufreq: schedutil: Call sugov_update_next_freq() before check to fast_switch_enabled
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Commit Message

Yue Hu Feb. 24, 2021, 5:42 a.m.
From: Yue Hu <huyue2@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 <huyue2@yulong.com>
---
 kernel/sched/cpufreq_schedutil.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

Comments

Yue Hu Feb. 24, 2021, 6:07 a.m. | #1
On Wed, 24 Feb 2021 11:32:36 +0530
Viresh Kumar <viresh.kumar@linaro.org> wrote:

> On 24-02-21, 13:42, Yue Hu wrote:
> > From: Yue Hu <huyue2@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 <huyue2@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);  
> 
> I will call this directly instead, no need of the wrapper anymore.

To fix it in next version.

Thank you.

> 
> >  }
> >  
> > -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);
> >  }  
>
Rafael J. Wysocki March 18, 2021, 6:50 p.m. | #2
On Wed, Feb 24, 2021 at 6:44 AM Yue Hu <zbestahu@gmail.com> wrote:
>

> From: Yue Hu <huyue2@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 <huyue2@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!

Patch

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);
 }