From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755463AbYFRRXs (ORCPT ); Wed, 18 Jun 2008 13:23:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752503AbYFRRXk (ORCPT ); Wed, 18 Jun 2008 13:23:40 -0400 Received: from ug-out-1314.google.com ([66.249.92.170]:13206 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752360AbYFRRXj (ORCPT ); Wed, 18 Jun 2008 13:23:39 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=dU+D7pjbbv1zPsDopr7xmMhMWMBUaX8FxIDRJSP92lWhHsarIad17c8DIBsarngGl+ WUOLsgn33iQLCVku/yZaIN5IHkDn/aZmPRnPchRp9BzoLsO4JzkP52jwmGC5aZWlCEXc 5i1bd6WvalVwGcbLvq5ev3KtHTovz7ogzxlqY= Date: Wed, 18 Jun 2008 21:23:16 +0400 From: Cyrill Gorcunov To: "Maciej W. Rozycki" Cc: Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , LKML Subject: Re: nmi_watchdog suspicious Message-ID: <20080618172316.GA10431@cvg> References: <20080610185759.GA7353@cvg> <20080616170000.GC7273@cvg> <20080617155120.GA9440@cvg> <20080618163905.GB7117@cvg> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Maciej W. Rozycki - Wed, Jun 18, 2008 at 05:54:32PM +0100] | On Wed, 18 Jun 2008, Cyrill Gorcunov wrote: | | > Maciej, it seems we are talking about different code snippets ;) | > I'm talking only about touch_nmi_watchdog(). By now (in -tip tree | > we have) | > | > void touch_nmi_watchdog(void) | > { | > if (nmi_watchdog == NMI_LOCAL_APIC || | > nmi_watchdog == NMI_IO_APIC) { | > unsigned cpu; | > ... | > | > so we check explicitly the values (so if touch_nmi_watchdog | > was called when nmi_watchdog = 0 or -1U this code will not | > be executed anyway). So I think I'm a bit lost, Maciej... I just | > can't figure out what is wrong with this code, so please help | > me ;). If you're talking about apic code in _general_ design | > then...well, I think I need some time to _understand_ the code | > say byte-by-byte first. | | The value of nmi_watchdog being NMI_IO_APIC or NMI_LOCAL_APIC does not | mean the watchdog has been set up already. This observation applies both | here and elsewhere, e.g. to nmi_watchdog_tick(). | | Maciej | If you mean the case we get NMI physical line assetred while configuring APIC (ie nmi watchdog is not properly configured yet) then I wonder why we has this checking at all... - Cyrill -