Re: [PATCH 08/13] xen/pvticketlock: disable interrupts while blocking

From: Don Zickus
Date: Tue Sep 13 2011 - 15:27:42 EST


On Tue, Sep 13, 2011 at 09:03:20PM +0200, Andi Kleen wrote:
> > So I got around to implementing this and it seems to work great. The back
> > to back NMIs are detected properly using the %rip and that info is passed to
> > the NMI notifier. That info is used to determine if only the first
> > handler to report 'handled' is executed or _all_ the handlers are
> > executed.
> >
> > I think all the 'unknown' NMIs I generated with various perf runs have
> > disappeared. I'll post a new version of my nmi notifier rewrite soon.
>
> This will fail when the system is idle.

Oh one other thing I forgot to mention is that an NMI handler has to
return a value greater than 1, meaning that it handle multiple NMI events
during this NMI to even enable the 'NMI swallowing' algorithm.

Cheers,
Don
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