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SubjectRe: [PATCH] sched: remove an unnecessary memory access, rq->cpu in __schedule()

* Byungchul Park <byungchul.park@lge.com> wrote:

> Is there any reason keeping this statement on the code?
>
> -----8<-----
> From d8a387efb8199b69b6464970d6f9fc57cbcf0ab0 Mon Sep 17 00:00:00 2001
> From: Byungchul Park <byungchul.park@lge.com>
> Date: Thu, 11 Feb 2016 11:50:53 +0900
> Subject: [PATCH] sched: remove an unnecessary memory access, rq->cpu in
> __schedule()
>
> Remove an unnecessary assignment of variable not used any more.
>
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> ---
> kernel/sched/core.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 1315cec..501f5d9 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3193,7 +3193,6 @@ static void __sched notrace __schedule(bool preempt)
>
> trace_sched_switch(preempt, prev, next);
> rq = context_switch(rq, prev, next); /* unlocks the rq */
> - cpu = cpu_of(rq);
> } else {
> lockdep_unpin_lock(&rq->lock);
> raw_spin_unlock_irq(&rq->lock);

There's no memory access that I can see - GCC will optimize it out.

Having said that, it is a dead statement so can be removed. I fixed the title
accordingly.

Thanks,

Ingo

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