[PATCH 0/1] sched/rt: code cleanup, remove a redundant function call

[PATCH 0/1] sched/rt: code cleanup, remove a redundant function call

[Shan Hai]

Calls the sched_rt_runtime twice in the sched_rt_runtime_exceeded, and the
second time call is not necessary, because the value of the rt_runtime was
alreay read and rt_runtimer itself was protected by the rt_runtime_lock.

---
 kernel/sched_rt.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

[PATCH 1/1] sched/rt: code cleanup, remove a redundant function call

[Shan Hai]

The second time call to sched_rt_period is redundant, because the value of the
rt_runtime was already read and it was protected by the rurt_runtime_lock.

Signed-off-by: Shan Hai <haishan.bai@gmail.com>
---
 kernel/sched_rt.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 056cbd2..2171ac8 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -645,7 +645,7 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
 	if (rt_rq->rt_throttled)
 		return rt_rq_throttled(rt_rq);
 
-	if (sched_rt_runtime(rt_rq) >= sched_rt_period(rt_rq))
+	if (runtime >= sched_rt_period(rt_rq))
 		return 0;
 
 	balance_runtime(rt_rq);
-- 
1.7.4.1

Re: [PATCH 1/1] sched/rt: code cleanup, remove a redundant function call

[Kamalesh Babulal]

* Shan Hai <haishan.bai@gmail.com> [2011-11-29 11:03:56]:

> The second time call to sched_rt_period is redundant, because the value of the
> rt_runtime was already read and it was protected by the rurt_runtime_lock.
> 
> Signed-off-by: Shan Hai <haishan.bai@gmail.com>

Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>

> ---
>  kernel/sched_rt.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
> index 056cbd2..2171ac8 100644
> --- a/kernel/sched_rt.c
> +++ b/kernel/sched_rt.c
> @@ -645,7 +645,7 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
>  	if (rt_rq->rt_throttled)
>  		return rt_rq_throttled(rt_rq);
> 
> -	if (sched_rt_runtime(rt_rq) >= sched_rt_period(rt_rq))
> +	if (runtime >= sched_rt_period(rt_rq))
>  		return 0;
> 
>  	balance_runtime(rt_rq);
> -- 
> 1.7.4.1

Re: [PATCH 1/1] sched/rt: code cleanup, remove a redundant function call

[Peter Zijlstra]

On Tue, 2011-11-29 at 11:03 +0800, Shan Hai wrote:
> The second time call to sched_rt_period is redundant, because the value of the
> rt_runtime was already read and it was protected by the rurt_runtime_lock.
> 
> Signed-off-by: Shan Hai <haishan.bai@gmail.com>
> ---
>  kernel/sched_rt.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)

Note that that file doesn't exist anymore, scheduler patches should be
posted against tip/master.

Anyway, fixed that up and applied it. Thanks!

Re: [PATCH 1/1] sched/rt: code cleanup, remove a redundant function call

[Shan Hai]

On Tue, Nov 29, 2011 at 02:17:02PM +0100, Peter Zijlstra wrote:
> On Tue, 2011-11-29 at 11:03 +0800, Shan Hai wrote:
> > The second time call to sched_rt_period is redundant, because the value of the
> > rt_runtime was already read and it was protected by the rurt_runtime_lock.
> > 
> > Signed-off-by: Shan Hai <haishan.bai@gmail.com>
> > ---
> >  kernel/sched_rt.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> Note that that file doesn't exist anymore, scheduler patches should be
> posted against tip/master.
>

Got it, thanks.

Cheers
Shan Hai
 
> Anyway, fixed that up and applied it. Thanks!

[tip:sched/core] sched/rt: Code cleanup, remove a redundant function call

[tip-bot for Shan Hai]

Commit-ID:  5b680fd61388abb9059fbc8e7a2f60f602bfce15
Gitweb:     http://git.kernel.org/tip/5b680fd61388abb9059fbc8e7a2f60f602bfce15
Author:     Shan Hai <haishan.bai@gmail.com>
AuthorDate: Tue, 29 Nov 2011 11:03:56 +0800
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 6 Dec 2011 09:06:28 +0100

sched/rt: Code cleanup, remove a redundant function call

The second call to sched_rt_period() is redundant, because the value of the
rt_runtime was already read and it was protected by the ->rt_runtime_lock.

Signed-off-by: Shan Hai <haishan.bai@gmail.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1322535836-13590-2-git-send-email-haishan.bai@gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/sched/rt.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 58a4844..3640ebb 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -846,7 +846,7 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
 	if (rt_rq->rt_throttled)
 		return rt_rq_throttled(rt_rq);
 
-	if (sched_rt_runtime(rt_rq) >= sched_rt_period(rt_rq))
+	if (runtime >= sched_rt_period(rt_rq))
 		return 0;
 
 	balance_runtime(rt_rq);