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.p...@lge.com>
> Reviewed-by: Steven Rostedt (VMware) <rost...@goodmis.org>
> Reviewed-by: Juri Lelli <juri.le...@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
