* [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl_task()
@ 2017-02-16 2:34 Byungchul Park
2017-02-16 2:34 ` [PATCH v3 2/2] sched/rt: Remove unnecessary condition in push_rt_task() Byungchul Park
` (3 more replies)
0 siblings, 4 replies; 11+ messages in thread
From: Byungchul Park @ 2017-02-16 2:34 UTC (permalink / raw)
To: peterz, mingo; +Cc: linux-kernel, juri.lelli, rostedt, kernel-team
pick_next_pushable_dl_task(rq) has BUG_ON(rq->cpu != task_cpu(task))
when it returns a task other than NULL, which means that task_cpu(task)
must be rq->cpu. So if task == next_task, then task_cpu(next_task) must
be rq->cpu as well. Remove the redundant condition and make code simpler.
By this patch, unnecessary one branch and two LOAD operations in 'if'
statement can be avoided.
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Juri Lelli <juri.lelli@arm.com>
---
kernel/sched/deadline.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 27737f3..ad8d577 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1483,7 +1483,7 @@ static int push_dl_task(struct rq *rq)
* then possible that next_task has migrated.
*/
task = pick_next_pushable_dl_task(rq);
- if (task_cpu(next_task) == rq->cpu && task == next_task) {
+ if (task == next_task) {
/*
* The task is still there. We don't try
* again, some other cpu will pull it when ready.
--
1.9.1
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH v3 2/2] sched/rt: Remove unnecessary condition in push_rt_task()
2017-02-16 2:34 [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl_task() Byungchul Park
@ 2017-02-16 2:34 ` Byungchul Park
2017-02-16 2:45 ` Steven Rostedt
2017-02-16 17:36 ` Daniel Bristot de Oliveira
2017-02-16 17:35 ` [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl_task() Daniel Bristot de Oliveira
` (2 subsequent siblings)
3 siblings, 2 replies; 11+ messages in thread
From: Byungchul Park @ 2017-02-16 2:34 UTC (permalink / raw)
To: peterz, mingo; +Cc: linux-kernel, juri.lelli, rostedt, kernel-team
pick_next_pushable_task(rq) has BUG_ON(rq_cpu != task_cpu(task)) when
it returns a task other than NULL, which means that task_cpu(task) must
be rq->cpu. So if task == next_task, then task_cpu(next_task) must be
rq->cpu as well. Remove the redundant condition and make code simpler.
By this patch, unnecessary one branch and two LOAD operations in 'if'
statement can be avoided.
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Juri Lelli <juri.lelli@arm.com>
---
kernel/sched/rt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 4101f9d..5abd9a52 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1820,7 +1820,7 @@ static int push_rt_task(struct rq *rq)
* pushing.
*/
task = pick_next_pushable_task(rq);
- if (task_cpu(next_task) == rq->cpu && task == next_task) {
+ if (task == next_task) {
/*
* The task hasn't migrated, and is still the next
* eligible task, but we failed to find a run-queue
--
1.9.1
^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH v3 2/2] sched/rt: Remove unnecessary condition in push_rt_task()
2017-02-16 2:34 ` [PATCH v3 2/2] sched/rt: Remove unnecessary condition in push_rt_task() Byungchul Park
@ 2017-02-16 2:45 ` Steven Rostedt
2017-02-16 3:03 ` Byungchul Park
2017-02-16 7:15 ` byungchul.park
2017-02-16 17:36 ` Daniel Bristot de Oliveira
1 sibling, 2 replies; 11+ messages in thread
From: Steven Rostedt @ 2017-02-16 2:45 UTC (permalink / raw)
To: Byungchul Park; +Cc: peterz, mingo, linux-kernel, juri.lelli, kernel-team
On Thu, 16 Feb 2017 11:34:17 +0900
Byungchul Park <byungchul.park@lge.com> wrote:
> pick_next_pushable_task(rq) has BUG_ON(rq_cpu != task_cpu(task)) when
> it returns a task other than NULL, which means that task_cpu(task) must
> be rq->cpu. So if task == next_task, then task_cpu(next_task) must be
> rq->cpu as well. Remove the redundant condition and make code simpler.
>
> By this patch, unnecessary one branch and two LOAD operations in 'if'
> statement can be avoided.
>
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> Reviewed-by: Juri Lelli <juri.lelli@arm.com>
> ---
This is a different patch, I don't believe Juri reviewed it yet.
-- Steve
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v3 2/2] sched/rt: Remove unnecessary condition in push_rt_task()
2017-02-16 2:45 ` Steven Rostedt
@ 2017-02-16 3:03 ` Byungchul Park
2017-02-16 7:15 ` byungchul.park
1 sibling, 0 replies; 11+ messages in thread
From: Byungchul Park @ 2017-02-16 3:03 UTC (permalink / raw)
To: Steven Rostedt; +Cc: peterz, mingo, linux-kernel, juri.lelli, kernel-team
On Wed, Feb 15, 2017 at 09:45:37PM -0500, Steven Rostedt wrote:
> On Thu, 16 Feb 2017 11:34:17 +0900
> Byungchul Park <byungchul.park@lge.com> wrote:
>
> > pick_next_pushable_task(rq) has BUG_ON(rq_cpu != task_cpu(task)) when
> > it returns a task other than NULL, which means that task_cpu(task) must
> > be rq->cpu. So if task == next_task, then task_cpu(next_task) must be
> > rq->cpu as well. Remove the redundant condition and make code simpler.
> >
> > By this patch, unnecessary one branch and two LOAD operations in 'if'
> > statement can be avoided.
> >
> > Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> > Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > Reviewed-by: Juri Lelli <juri.lelli@arm.com>
> > ---
>
> This is a different patch, I don't believe Juri reviewed it yet.
I will take care not to make this kind of mistake next time.
Thank you very much.
>
> -- Steve
^ permalink raw reply [flat|nested] 11+ messages in thread
* RE: [PATCH v3 2/2] sched/rt: Remove unnecessary condition in push_rt_task()
2017-02-16 2:45 ` Steven Rostedt
2017-02-16 3:03 ` Byungchul Park
@ 2017-02-16 7:15 ` byungchul.park
2017-02-16 8:43 ` Juri Lelli
1 sibling, 1 reply; 11+ messages in thread
From: byungchul.park @ 2017-02-16 7:15 UTC (permalink / raw)
To: juri.lelli
Cc: peterz, mingo, linux-kernel, kernel-team, 'Steven Rostedt'
> -----Original Message-----
> From: Steven Rostedt [mailto:rostedt@goodmis.org]
> Sent: Thursday, February 16, 2017 11:46 AM
> To: Byungchul Park
> Cc: peterz@infradead.org; mingo@kernel.org; linux-kernel@vger.kernel.org;
> juri.lelli@gmail.com; kernel-team@lge.com
> Subject: Re: [PATCH v3 2/2] sched/rt: Remove unnecessary condition in
> push_rt_task()
>
> On Thu, 16 Feb 2017 11:34:17 +0900
> Byungchul Park <byungchul.park@lge.com> wrote:
>
> > pick_next_pushable_task(rq) has BUG_ON(rq_cpu != task_cpu(task)) when
> > it returns a task other than NULL, which means that task_cpu(task) must
> > be rq->cpu. So if task == next_task, then task_cpu(next_task) must be
> > rq->cpu as well. Remove the redundant condition and make code simpler.
> >
> > By this patch, unnecessary one branch and two LOAD operations in 'if'
> > statement can be avoided.
> >
> > Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> > Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > Reviewed-by: Juri Lelli <juri.lelli@arm.com>
> > ---
>
> This is a different patch, I don't believe Juri reviewed it yet.
Hello juri,
I should have asked you first and been more careful before I added
'reviewed-by'. Can I ask you for your opinion about the additional one?
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v3 2/2] sched/rt: Remove unnecessary condition in push_rt_task()
2017-02-16 7:15 ` byungchul.park
@ 2017-02-16 8:43 ` Juri Lelli
0 siblings, 0 replies; 11+ messages in thread
From: Juri Lelli @ 2017-02-16 8:43 UTC (permalink / raw)
To: byungchul.park
Cc: juri.lelli, peterz, mingo, linux-kernel, kernel-team,
'Steven Rostedt'
Hi,
On 16/02/17 16:15, byungchul.park wrote:
> > -----Original Message-----
> > From: Steven Rostedt [mailto:rostedt@goodmis.org]
> > Sent: Thursday, February 16, 2017 11:46 AM
> > To: Byungchul Park
> > Cc: peterz@infradead.org; mingo@kernel.org; linux-kernel@vger.kernel.org;
> > juri.lelli@gmail.com; kernel-team@lge.com
> > Subject: Re: [PATCH v3 2/2] sched/rt: Remove unnecessary condition in
> > push_rt_task()
> >
> > On Thu, 16 Feb 2017 11:34:17 +0900
> > Byungchul Park <byungchul.park@lge.com> wrote:
> >
> > > pick_next_pushable_task(rq) has BUG_ON(rq_cpu != task_cpu(task)) when
> > > it returns a task other than NULL, which means that task_cpu(task) must
> > > be rq->cpu. So if task == next_task, then task_cpu(next_task) must be
> > > rq->cpu as well. Remove the redundant condition and make code simpler.
> > >
> > > By this patch, unnecessary one branch and two LOAD operations in 'if'
> > > statement can be avoided.
> > >
> > > Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> > > Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > > Reviewed-by: Juri Lelli <juri.lelli@arm.com>
> > > ---
> >
> > This is a different patch, I don't believe Juri reviewed it yet.
>
> Hello juri,
>
> I should have asked you first and been more careful before I added
> 'reviewed-by'. Can I ask you for your opinion about the additional one?
>
Looks good to me, you can leave my Reviewed-by.
Steve, thanks for pointing out that I didn't yet reviewed it. :)
Thanks,
- Juri
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl_task()
2017-02-16 2:34 [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl_task() Byungchul Park
2017-02-16 2:34 ` [PATCH v3 2/2] sched/rt: Remove unnecessary condition in push_rt_task() Byungchul Park
@ 2017-02-16 17:35 ` Daniel Bristot de Oliveira
2017-03-21 2:56 ` Byungchul Park
2017-02-22 5:00 ` Byungchul Park
2017-05-02 7:43 ` Byungchul Park
3 siblings, 1 reply; 11+ messages in thread
From: Daniel Bristot de Oliveira @ 2017-02-16 17:35 UTC (permalink / raw)
To: Byungchul Park, peterz, mingo
Cc: linux-kernel, juri.lelli, rostedt, kernel-team
On 02/16/2017 03:34 AM, Byungchul Park wrote:
> pick_next_pushable_dl_task(rq) has BUG_ON(rq->cpu != task_cpu(task))
> when it returns a task other than NULL, which means that task_cpu(task)
> must be rq->cpu. So if task == next_task, then task_cpu(next_task) must
> be rq->cpu as well. Remove the redundant condition and make code simpler.
>
> By this patch, unnecessary one branch and two LOAD operations in 'if'
> statement can be avoided.
>
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> Reviewed-by: Juri Lelli <juri.lelli@arm.com>
+1
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
-- Daniel
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v3 2/2] sched/rt: Remove unnecessary condition in push_rt_task()
2017-02-16 2:34 ` [PATCH v3 2/2] sched/rt: Remove unnecessary condition in push_rt_task() Byungchul Park
2017-02-16 2:45 ` Steven Rostedt
@ 2017-02-16 17:36 ` Daniel Bristot de Oliveira
1 sibling, 0 replies; 11+ messages in thread
From: Daniel Bristot de Oliveira @ 2017-02-16 17:36 UTC (permalink / raw)
To: Byungchul Park, peterz, mingo
Cc: linux-kernel, juri.lelli, rostedt, kernel-team
On 02/16/2017 03:34 AM, Byungchul Park wrote:
> pick_next_pushable_task(rq) has BUG_ON(rq_cpu != task_cpu(task)) when
> it returns a task other than NULL, which means that task_cpu(task) must
> be rq->cpu. So if task == next_task, then task_cpu(next_task) must be
> rq->cpu as well. Remove the redundant condition and make code simpler.
>
> By this patch, unnecessary one branch and two LOAD operations in 'if'
> statement can be avoided.
>
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> Reviewed-by: Juri Lelli <juri.lelli@arm.com>
+1
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
-- Daniel
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl_task()
2017-02-16 2:34 [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl_task() Byungchul Park
2017-02-16 2:34 ` [PATCH v3 2/2] sched/rt: Remove unnecessary condition in push_rt_task() Byungchul Park
2017-02-16 17:35 ` [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl_task() Daniel Bristot de Oliveira
@ 2017-02-22 5:00 ` Byungchul Park
2017-05-02 7:43 ` Byungchul Park
3 siblings, 0 replies; 11+ messages in thread
From: Byungchul Park @ 2017-02-22 5:00 UTC (permalink / raw)
To: peterz, mingo; +Cc: linux-kernel, juri.lelli, rostedt, kernel-team
On Thu, Feb 16, 2017 at 11:34:16AM +0900, Byungchul Park wrote:
> pick_next_pushable_dl_task(rq) has BUG_ON(rq->cpu != task_cpu(task))
> when it returns a task other than NULL, which means that task_cpu(task)
> must be rq->cpu. So if task == next_task, then task_cpu(next_task) must
> be rq->cpu as well. Remove the redundant condition and make code simpler.
>
> By this patch, unnecessary one branch and two LOAD operations in 'if'
> statement can be avoided.
Hello,
What do you think?
>
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> Reviewed-by: Juri Lelli <juri.lelli@arm.com>
> ---
> kernel/sched/deadline.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 27737f3..ad8d577 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -1483,7 +1483,7 @@ static int push_dl_task(struct rq *rq)
> * then possible that next_task has migrated.
> */
> task = pick_next_pushable_dl_task(rq);
> - if (task_cpu(next_task) == rq->cpu && task == next_task) {
> + if (task == next_task) {
> /*
> * The task is still there. We don't try
> * again, some other cpu will pull it when ready.
> --
> 1.9.1
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl_task()
2017-02-16 17:35 ` [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl_task() Daniel Bristot de Oliveira
@ 2017-03-21 2:56 ` Byungchul Park
0 siblings, 0 replies; 11+ messages in thread
From: Byungchul Park @ 2017-03-21 2:56 UTC (permalink / raw)
To: peterz, mingo
Cc: peterz, mingo, linux-kernel, juri.lelli, rostedt, kernel-team,
Daniel Bristot de Oliveira
On Thu, Feb 16, 2017 at 06:35:54PM +0100, Daniel Bristot de Oliveira wrote:
> On 02/16/2017 03:34 AM, Byungchul Park wrote:
> > pick_next_pushable_dl_task(rq) has BUG_ON(rq->cpu != task_cpu(task))
> > when it returns a task other than NULL, which means that task_cpu(task)
> > must be rq->cpu. So if task == next_task, then task_cpu(next_task) must
> > be rq->cpu as well. Remove the redundant condition and make code simpler.
> >
> > By this patch, unnecessary one branch and two LOAD operations in 'if'
> > statement can be avoided.
> >
> > Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> > Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > Reviewed-by: Juri Lelli <juri.lelli@arm.com>
>
> +1
>
> Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Hello,
Could you check this out?
>
> -- Daniel
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl_task()
2017-02-16 2:34 [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl_task() Byungchul Park
` (2 preceding siblings ...)
2017-02-22 5:00 ` Byungchul Park
@ 2017-05-02 7:43 ` Byungchul Park
3 siblings, 0 replies; 11+ messages in thread
From: Byungchul Park @ 2017-05-02 7:43 UTC (permalink / raw)
To: peterz, mingo; +Cc: linux-kernel, juri.lelli, rostedt, kernel-team
On Thu, Feb 16, 2017 at 11:34:16AM +0900, Byungchul Park wrote:
> pick_next_pushable_dl_task(rq) has BUG_ON(rq->cpu != task_cpu(task))
> when it returns a task other than NULL, which means that task_cpu(task)
> must be rq->cpu. So if task == next_task, then task_cpu(next_task) must
> be rq->cpu as well. Remove the redundant condition and make code simpler.
>
> By this patch, unnecessary one branch and two LOAD operations in 'if'
> statement can be avoided.
>
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> Reviewed-by: Juri Lelli <juri.lelli@arm.com>
Hello,
These two patches remove definitely unnecessary condition statements.
Please review it.
Thanks,
Byungchul
> ---
> kernel/sched/deadline.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 27737f3..ad8d577 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -1483,7 +1483,7 @@ static int push_dl_task(struct rq *rq)
> * then possible that next_task has migrated.
> */
> task = pick_next_pushable_dl_task(rq);
> - if (task_cpu(next_task) == rq->cpu && task == next_task) {
> + if (task == next_task) {
> /*
> * The task is still there. We don't try
> * again, some other cpu will pull it when ready.
> --
> 1.9.1
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2017-05-02 7:44 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-02-16 2:34 [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl_task() Byungchul Park
2017-02-16 2:34 ` [PATCH v3 2/2] sched/rt: Remove unnecessary condition in push_rt_task() Byungchul Park
2017-02-16 2:45 ` Steven Rostedt
2017-02-16 3:03 ` Byungchul Park
2017-02-16 7:15 ` byungchul.park
2017-02-16 8:43 ` Juri Lelli
2017-02-16 17:36 ` Daniel Bristot de Oliveira
2017-02-16 17:35 ` [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl_task() Daniel Bristot de Oliveira
2017-03-21 2:56 ` Byungchul Park
2017-02-22 5:00 ` Byungchul Park
2017-05-02 7:43 ` Byungchul Park
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.