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Subject: Re: [RFC][PATCH 06/22] sched: SCHED_DEADLINE handles spacial
 kthreads
From: Dario Faggioli <faggioli@gandalf.sssup.it>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
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On Thu, 2010-11-11 at 15:31 +0100, Peter Zijlstra wrote:
> > Since SCHED_DEADLINE is now the highest priority scheduling class
> > these tasks have to be handled therein, but it is not obvious how
> > to choose a runtime and a deadline that guarantee what explained
> > above. Therefore, we need a mean of recognizing system tasks inside
> > the -deadline class and always run them as soon as possible, without
> > any kind of runtime and bandwidth limitation.
>=20
> Yet in the previous patch you had this hunk:
>=20
> > +++ b/kernel/sched_stoptask.c
> > @@ -81,7 +81,7 @@ get_rr_interval_stop(struct rq *rq, struct
> > task_struct *task)
> >   * Simple, special scheduling class for the per-CPU stop tasks:
> >   */
> >  static const struct sched_class stop_sched_class =3D {
> > -       .next                   =3D &rt_sched_class,
> > +       .next                   =3D &dl_sched_class,
> > =20
> >         .enqueue_task           =3D enqueue_task_stop,
> >         .dequeue_task           =3D dequeue_task_stop,
>=20
Yep. And (as said on IRC) this needs serious cleanup, in favour of
stop_task!

I'll completely drop patch 06 for next releases.

Thanks,
Dario

--=20
<<This happens because I choose it to happen!>> (Raistlin Majere)
----------------------------------------------------------------------
Dario Faggioli, ReTiS Lab, Scuola Superiore Sant'Anna, Pisa  (Italy)

http://blog.linux.it/raistlin / raistlin@ekiga.net /
dario.faggioli@jabber.org

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