Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759177Ab0KRPi1 (ORCPT ); Thu, 18 Nov 2010 10:38:27 -0500 Received: from canuck.infradead.org ([134.117.69.58]:49988 "EHLO canuck.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753786Ab0KRPiZ convert rfc822-to-8bit (ORCPT ); Thu, 18 Nov 2010 10:38:25 -0500 Subject: Re: [V2 PATCH 0/6] x86, NMI: give NMI handler a face-lift From: Peter Zijlstra To: Jason Wessel Cc: Ingo Molnar , Don Zickus , Robert Richter , ying.huang@intel.com, Andi Kleen , LKML , Frederic Weisbecker In-Reply-To: <1290086232.2109.1507.camel@laptop> References: <1289573033-2889-1-git-send-email-dzickus@redhat.com> <4CDD579F.80009@windriver.com> <20101112154231.GN4823@redhat.com> <4CDD6389.2080206@windriver.com> <20101112161144.GP4823@redhat.com> <4CDD6CAD.30303@windriver.com> <20101112172755.GR4823@redhat.com> <20101116184325.GB4823@redhat.com> <4CE2E3C3.6060800@windriver.com> <20101118080516.GJ32621@elte.hu> <4CE52048.5080802@windriver.com> <1290086232.2109.1507.camel@laptop> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Thu, 18 Nov 2010 16:38:27 +0100 Message-ID: <1290094707.2109.1524.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 970 Lines: 23 On Thu, 2010-11-18 at 14:17 +0100, Peter Zijlstra wrote: > On Thu, 2010-11-18 at 06:47 -0600, Jason Wessel wrote: > > More specifically > > when another subsystem injects an NMI event the perf NMI code returns > > NOTIFY_STOP. > > Not unconditionally, right? We only do so when the previous NMI was from > the PMU and nobody claimed this one (NOTIFY_STOP from DIE_NMIUNKNOWN). > > Or are you hitting the other one, where !handled but pmu_nmi.handled > > 1 ? I'm just thinking here, shouldn't we do that (!handle && pmu_nmi.handle > 1) case from DIE_NMIUNKNOWN as well? and only ever return NOTIFY_STOP when handled != 0? That way all NMIs at least traverse the regular DIE_NMI chain once and we only kill redundant NMIs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/