Subject: Re: [RFC/RFT PATCH v3] sched: automated per tty task groups
From: Mike Galbraith <efault@gmx.de>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Markus Trippelsdorf <markus@trippelsdorf.de>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>
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Date: Tue, 16 Nov 2010 07:19:52 -0700
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On Tue, 2010-11-16 at 15:01 +0100, Peter Zijlstra wrote:
> On Mon, 2010-11-15 at 14:25 -0700, Mike Galbraith wrote:
> > > > +   if (p->flags & PF_EXITING)
> > > > +           return false;
> > > 
> > > Hmm, why? Perhaps PF_EXITING was needed in the previous version to
> > > avoid the race with release_task(). But now it is always safe to
> > > use signal->autogroup.
> > 
> > That came into existence when I stress tested previous version in
> > PREEMPT_RT (boom).  I see no good reason to bother an exiting task
> > though, so would prefer to leave it as is. 
> 
> PREEMPT_RT has a slightly different exit path IIRC. If that was the only
> thing you saw it explode on we could leave the check out for now and
> revisit it in the -rt patches when and if it pops up. Hmm?

Yeah, I'm going to whack it.  (and add your lockdep thingy)

	-Mike


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