Messages in this thread | | | Subject | Re: [RFC][PATCH 06/22] sched: SCHED_DEADLINE handles spacial kthreads | From | Peter Zijlstra <> | Date | Thu, 11 Nov 2010 16:43:22 +0100 |
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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.
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