Re: [PATCH] sched: deduplicate mm checks in normalize_rt_tasks()

From: Yong Zhang
Date: Thu Apr 21 2011 - 09:43:26 EST


On Thu, Apr 21, 2011 at 09:29:04PM +0800, Yong Zhang wrote:
> On Thu, Apr 21, 2011 at 09:15:56PM +0800, Hillf Danton wrote:
> > When normalizing realtime tasks, only user tasks are concerned by
> > checking their ->mm.
> > If the task is not realtime, the -mm is checked again, thus the
> > overwork could be removed.
> >
> > Signed-off-by: Hillf Danton <dhillf@xxxxxxxxx>
> > ---
> >
> > --- a/kernel/sched.c 2011-03-30 03:09:48.000000000 +0800
> > +++ b/kernel/sched.c 2011-04-21 20:59:28.000000000 +0800
> > @@ -8364,7 +8364,7 @@ void normalize_rt_tasks(void)
> > * Renice negative nice level userspace
> > * tasks back to 0:
> > */
> > - if (TASK_NICE(p) < 0 && p->mm)
> > + if (TASK_NICE(p) < 0)
>
> This looks good.
>
> And we can also move TASK_NICE(p) < 0 to the upper if(),
> like:
> if (!rt_task(p) && TASK_NICE(p) < 0) {
> set_user_nice(p, 0);
> continue;
> }
>
> to reduce one level if() to make code cleaner :)

Damm, I'm wrong here, just ignore it.

Yours is good.

Reviewed-by: Yong Zhang <yong.zhang0@xxxxxxxxx>

>
> Thanks,
> Yong
>
> > set_user_nice(p, 0);
> > continue;
> > }
> > --
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