Re: [PATCH/RFC] sched: Remove SYSTEM_RUNNING checks fromcond_resched*()

From: Peter Zijlstra
Date: Wed Jul 08 2009 - 08:12:44 EST


On Wed, 2009-07-08 at 16:03 +0400, Anton Vorontsov wrote:
> On Wed, Jul 08, 2009 at 08:24:23AM +0200, Peter Zijlstra wrote:
> > On Wed, 2009-07-08 at 02:50 +0200, Oleg Nesterov wrote:
> >
> > > /*
> > > * It is valid to assume CPU-locality during early bootup:
> > > */
> > > if (system_state != SYSTEM_RUNNING)
> > > goto out;
> > >
> > > this doesn't look right, smp_init() is called before we set
> > > SYSTEM_RUNNING.
> >
> > The thing is, there's also ton's of code that might end up calling
> > cond_resched() and co before the scheduler is fully initialized.
>
> Hm. Speaking of cond_resched*() only, then it should be pretty
> safe to convert the SYSTEM_RUNNING checks to scheduler_running,
> no? scheduler_running is set after sched_init().

Hmm, that might work, I'd have to audit sched_init_smp() as it seems to
do way too much...


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