Re: [PATCH] sched: remove useless code in yield_to

From: Mike Galbraith
Date: Thu Jul 12 2012 - 14:44:59 EST


On Thu, 2012-07-12 at 16:07 +0200, Peter Zijlstra wrote:
> On Tue, 2012-07-03 at 14:34 +0800, Michael Wang wrote:
> > From: Michael Wang <wangyun@xxxxxxxxxxxxxxxxxx>
> >
> > it's impossible to enter else branch if we have set skip_clock_update
> > in task_yield_fair(), as yield_to_task_fair() will directly return
> > true after invoke task_yield_fair().
>
> It helps if you CC the guy who wrote the code.. I think you're right,
> although getting that skip_clock_update crap wrong is annoying.

Getting that crap wrong is ease, so Michael is probably right.

> Mike?

If it looks right to you too, it likely is. When I have time to look
for nanoseconds again, I can squeak if/when I find some. In any case,
for normal scheduler citizens, it's chump change, so nuke it.
> > Signed-off-by: Michael Wang <wangyun@xxxxxxxxxxxxxxxxxx>
> > ---
> > kernel/sched/core.c | 7 -------
> > 1 files changed, 0 insertions(+), 7 deletions(-)
> >
> > diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> > index 9bb7d28..77c14aa 100644
> > --- a/kernel/sched/core.c
> > +++ b/kernel/sched/core.c
> > @@ -4737,13 +4737,6 @@ again:
> > */
> > if (preempt && rq != p_rq)
> > resched_task(p_rq->curr);
> > - } else {
> > - /*
> > - * We might have set it in task_yield_fair(), but are
> > - * not going to schedule(), so don't want to skip
> > - * the next update.
> > - */
> > - rq->skip_clock_update = 0;
> > }
> >
> > out:
>
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