From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andi Kleen <andi@firstfloor.org>
Subject: Re: [PATCH 08/13] xen/pvticketlock: disable interrupts while blocking
Date: Tue, 13 Sep 2011 21:03:20 +0200
Message-ID: <20110913190320.GR7761@one.firstfloor.org>
References: <4E66615E.8070806@goop.org> <20110906182758.GR5795@redhat.com> <4E66EF86.9070200@redhat.com> <20110907134411.GV5795@redhat.com> <4E678992.5050709@redhat.com> <20110907155657.GX5795@redhat.com> <4E679AF4.50209@redhat.com> <20110907165203.GQ6838@redhat.com> <4E67A551.4000502@redhat.com> <20110913184044.GN5795@redhat.com>
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To: Don Zickus <dzickus@redhat.com>
Cc: Avi Kivity <avi@redhat.com>, Jeremy Fitzhardinge <jeremy@goop.org>, Peter Zijlstra <peterz@infradead.org>, "H. Peter Anvin" <hpa@zytor.com>, Linus Torvalds <torvalds@linux-foundation.org>, Ingo Molnar <mingo@elte.hu>, the arch/x86 maintainers <x86@kernel.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Nick Piggin <npiggin@kernel.dk>, Marcelo Tosatti <mtosatti@redhat.com>, KVM <kvm@vger.kernel.org>, Andi Kleen <andi@firstfloor.org>, Xen Devel <xen-devel@lists.xensource.com>, Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>
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> 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.

-Andi