Messages in this thread Patch in this message | | | Date | Tue, 23 May 2017 01:45:24 -0700 | From | tip-bot for Byungchul Park <> | Subject | [tip:sched/core] sched/deadline: Remove unnecessary condition in push_dl_task() |
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Commit-ID: a776b968e52895a350d636e6e7fdcb3b10846fa4 Gitweb: http://git.kernel.org/tip/a776b968e52895a350d636e6e7fdcb3b10846fa4 Author: Byungchul Park <byungchul.park@lge.com> AuthorDate: Fri, 12 May 2017 10:05:59 +0900 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Tue, 23 May 2017 10:01:33 +0200
sched/deadline: Remove unnecessary condition in push_dl_task()
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 the code simpler.
This way one unnecessary branch and two LOAD operations can be avoided.
Signed-off-by: Byungchul Park <byungchul.park@lge.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Juri Lelli <juri.lelli@arm.com> Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: <kernel-team@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1494551159-22367-1-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- 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 a2ce590..df6c291 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1533,7 +1533,7 @@ retry: * 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.
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