Re: mlockall triggred rcu_preempt stall.

From: Dave Jones
Date: Fri Jul 19 2013 - 20:32:33 EST


On Fri, Jul 19, 2013 at 03:15:39PM -0700, Paul E. McKenney wrote:
> On Fri, Jul 19, 2013 at 10:53:23AM -0400, Dave Jones wrote:
> > My fuzz tester keeps hitting this. Every instance shows the non-irq stack
> > came in from mlockall. I'm only seeing this on one box, but that has more
> > ram (8gb) than my other machines, which might explain it.
>
> Are you building CONFIG_PREEMPT=n? I don't see any preemption points in
> do_mlockall(), so a range containing enough vmas might well stall the
> CPU in that case.

That was with full preempt.

> Does the patch below help? If so, we probably need others, but let's
> first see if this one helps. ;-)

I'll try it on Monday.

Dave

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