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    SubjectRe: [RFC 0/12][PATCH] SCHED_DEADLINE: fork and terminate task logic
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    On Wed, 2010-01-13 at 17:15 +0100, Peter Zijlstra wrote:
    > On Wed, 2010-01-13 at 12:11 +0100, Raistlin wrote:
    >
    > > > > + } else if (rt_prio(p->prio))
    > > > > + p->sched_class = &rt_sched_class;
    > > > > + else
    > > > > p->sched_class = &fair_sched_class;
    > > > >
    > > > > #ifdef CONFIG_SMP
    > > > > @@ -2744,6 +2756,10 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
    > > > > if (mm)
    > > > > mmdrop(mm);
    > > > > if (unlikely(prev_state == TASK_DEAD)) {
    > > > > + /* a deadline task is dying: stop the bandwidth timer */
    > > > > + if (deadline_task(prev))
    > > > > + hrtimer_cancel(&prev->dl.dl_timer);
    > > > > +
    > > > > /*
    > > > > * Remove function-return probe instances associated with this
    > > > > * task and put them back on the free list.
    > > >
    > > > Shouldn't this be done in the ->dequeue_task() callback?
    > > >
    > > Not sure of this snippet... Actually, it is one of the most disturbing
    > > piece of code of this whole scheduler. :-(
    > >
    > > The reason why it is here is that I think it is needed to call
    > > hrtimer_cancel() _without_ holding the rq->lock, is that correct?
    >
    > I think we can nest the hrtimer base lock inside the rq->lock these
    > days, so it should be safe to call while holding it, anyway, lockdep
    > will quickly tell you if you try ;-)
    >
    Nice, I'll try this soon, thanks.

    > > It is
    >
    > Is that a stmt or an unfinished sentence?
    >
    No, this is nothing, sorry! :-P

    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@ekiga.net /
    dario.faggioli@jabber.org
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