Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755860AbYJ3RIU (ORCPT ); Thu, 30 Oct 2008 13:08:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754917AbYJ3RIG (ORCPT ); Thu, 30 Oct 2008 13:08:06 -0400 Received: from mx2.redhat.com ([66.187.237.31]:42944 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754219AbYJ3RID (ORCPT ); Thu, 30 Oct 2008 13:08:03 -0400 Date: Thu, 30 Oct 2008 13:08:50 -0400 From: Aristeu Rozanski To: Randy Dunlap Cc: "Maciej W. Rozycki" , linux-kernel@vger.kernel.org, Ingo Molnar Subject: [PATCH] nmi_watchdog: update procfs nmi_watchdog file documentation v2 Message-ID: <20081030170850.GQ771@redhat.com> References: <20081030151712.GO771@redhat.com> <20081030091921.79c04ec6.randy.dunlap@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081030091921.79c04ec6.randy.dunlap@oracle.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2191 Lines: 49 This patch updates the /proc/sys/kernel/nmi_watchdog documentation. Updated: included Randy Dunlap's corrections. Signed-off-by: Aristeu Rozanski --- Documentation/filesystems/proc.txt | 11 +++++++---- Documentation/nmi_watchdog.txt | 5 +++++ 2 files changed, 12 insertions(+), 4 deletions(-) --- linus-2.6.orig/Documentation/nmi_watchdog.txt 2008-10-24 11:41:30.000000000 -0400 +++ linus-2.6/Documentation/nmi_watchdog.txt 2008-10-30 13:05:46.000000000 -0400 @@ -69,6 +69,11 @@ to the overall system performance. On x86 nmi_watchdog is disabled by default so you have to enable it with a boot time parameter. +It's possible to disable the NMI watchdog in run-time by writing "0" to +/proc/sys/kernel/nmi_watchdog. Writing "1" to the same file will re-enable +the NMI watchdog. Notice that you still need to use "nmi_watchdog=" parameter +at boot time. + NOTE: In kernels prior to 2.4.2-ac18 the NMI-oopser is enabled unconditionally on x86 SMP boxes. --- linus-2.6.orig/Documentation/filesystems/proc.txt 2008-10-24 11:41:28.000000000 -0400 +++ linus-2.6/Documentation/filesystems/proc.txt 2008-10-30 13:05:31.000000000 -0400 @@ -1338,10 +1338,13 @@ nmi_watchdog Enables/Disables the NMI watchdog on x86 systems. When the value is non-zero the NMI watchdog is enabled and will continuously test all online cpus to -determine whether or not they are still functioning properly. - -Because the NMI watchdog shares registers with oprofile, by disabling the NMI -watchdog, oprofile may have more registers to utilize. +determine whether or not they are still functioning properly. Currently, +passing "nmi_watchdog=" parameter at boot time is required for this function +to work. + +If LAPIC NMI watchdog method is in use (nmi_watchdog=2 kernel parameter), the +NMI watchdog shares registers with oprofile. By disabling the NMI watchdog, +oprofile may have more registers to utilize. msgmni ------ -- 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/