Re: [RFC 0/9] mce recovery for Sandy Bridge server

From: Ingo Molnar
Date: Tue May 24 2011 - 17:42:10 EST



* Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:

> On Tue, 2011-05-24 at 14:30 -0700, Linus Torvalds wrote:
> > On Tue, May 24, 2011 at 2:24 PM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
> > >
> > > Right, so you can't do things like that from NMI context, but what perf
> > > can do is raise a self-IPI and continue from IRQ context (question for
> > > the HW folks, can there be cycles between the NMI iret and IRQ assert
> > > from whatever context was before the NMI hit?)
> >
> > Of course there can be - the code where the NMI hit may have
> > interrupts disabled.
>
> D'0h yes of course!..
>
> Then I can't immediately see a way to stop a thread dead in its tracks.
> Userspace yes, but not kernel-space.

It's a best-effort thing: run proper kernel code (hardirq context) as soon as
possible - but obviously not sooner than that! :-)

Thanks,

Ingo
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