Re: [RFC 0/12][PATCH] SCHED_DEADLINE: core of the scheduling class

[Dario Faggioli]

On Tue, 2009-12-29 at 13:25 +0100, Peter Zijlstra wrote:
> On Fri, 2009-10-16 at 17:40 +0200, Raistlin wrote:
> > @@ -5966,10 +5982,14 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
> >         if (running)
> >                 p->sched_class->put_prev_task(rq, p);
> >  
> > -       if (rt_prio(prio))
> > -               p->sched_class = &rt_sched_class;
> > -       else
> > -               p->sched_class = &fair_sched_class;
> > +       if (deadline_task(p))
> > +               p->sched_class = &deadline_sched_class;
> > +       else {
> > +               if (rt_prio(prio))
> > +                       p->sched_class = &rt_sched_class;
> > +               else
> > +                       p->sched_class = &fair_sched_class;
> > +       } 
> 
> This looks wrong.
> 
Completely agree! :-P

> This is PI code, so the effective class should be determined based on
> the 'priority' not on the 'policy'.
> 
Agree, but...

> I understand we don't yet have deadline inheritance like things in
> place, but this would be where we should make use of the simple ceiling
> protocol to boost things for now.
> 
... You got it! This is me having no idea of what solution would be
better since no deadline/bandwidth/whatever inheritance is in place
right now.

Now that you gave a direction, I'll follow right that path! :-)

Thanks and regards,
Dario

-- 
<<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@xxxxxxxxx /
dario.faggioli@xxxxxxxxxx

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