Re: [PATCH 04/10] nohz: Remove useless argument on tick_nohz_task_switch()

From: Peter Zijlstra
Date: Mon Aug 03 2015 - 09:05:00 EST


On Mon, Aug 03, 2015 at 02:49:54PM +0200, Frederic Weisbecker wrote:
> On Mon, Aug 03, 2015 at 02:39:59PM +0200, Peter Zijlstra wrote:
> > On Thu, Jul 23, 2015 at 06:42:09PM +0200, Frederic Weisbecker wrote:
> > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> > > index 78b4bad10..4d34035 100644
> > > --- a/kernel/sched/core.c
> > > +++ b/kernel/sched/core.c
> > > @@ -2489,7 +2489,7 @@ static struct rq *finish_task_switch(struct task_struct *prev)
> > > put_task_struct(prev);
> > > }
> > >
> > > - tick_nohz_task_switch(current);
> > > + tick_nohz_task_switch();
> > > return rq;
> > > }
> >
> > OK, so I just noticed this one. Please explain? WTF does it make sense
> > to have per task tick state?
> >
> > If we have >1 tasks, we need the tick. If we have 1 task, per-task ==
> > per-cpu.
> >
> > So what gives?
>
> tick_nohz_task_switch() is removed in the end of the patchset. There is no
> more per task dependency after this specific set.

OK, I'll keep reading ;-)
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