lkml.org 
[lkml]   [2010]   [Nov]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [RFC][PATCH 06/22] sched: SCHED_DEADLINE handles spacial kthreads
From
Date
On Thu, 2010-11-11 at 16:27 +0100, Oleg Nesterov wrote:
> On 11/11, Peter Zijlstra wrote:
> >
> > On Fri, 2010-10-29 at 08:31 +0200, Raistlin wrote:
> > > @@ -6071,7 +6104,7 @@ void sched_idle_next(void)
> > > */
> > > raw_spin_lock_irqsave(&rq->lock, flags);
> > >
> > > - __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
> > > + __setscheduler_dl_special(rq, p);
> > >
> > > activate_task(rq, p, 0);
> > >
> >
> > Ingo, happen to know if this is really needed these days? hotplug should
> > have migrated all other tasks away, leaving only the idle task to run.
>
> This is called before CPU_DEAD stage which migrates all tasks away.
>
>
> Sorry, can't resist, off-topic quiestion. Do we really need
> migration_call()->migrate_live_tasks() ?
>
> With the recent changes, try_to_wake_up() can never choose
> the dead (!cpu_online) cpu if the task was deactivated.
>
> Looks like we should only worry about the running tasks, and
> migrate_dead_tasks()->pick_next_task() loop seems to all work
> we need.
>
> (Of course, we can't just remove migrate_live_tasks(), at leat
> migrate_dead() needs simple changes).
>
> What do you think?

Yes, I think we can make that work, we could even move that
migrate_live_tasks() into CPU_DYING, which is before this point.


\
 
 \ /
  Last update: 2010-11-11 16:45    [W:0.129 / U:0.188 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site