From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753773AbbAUOao (ORCPT ); Wed, 21 Jan 2015 09:30:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:23866 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753131AbbAUOai (ORCPT ); Wed, 21 Jan 2015 09:30:38 -0500 Date: Wed, 21 Jan 2015 09:30:28 -0500 From: Don Zickus To: Andrew Jones Cc: Anton Blanchard , uobergfe@redhat.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, Michael Ellerman Subject: Re: Confusing behaviour with /proc/sys/kernel/nmi_watchdog Message-ID: <20150121143028.GD116159@redhat.com> References: <20141105093420.1c7500d8@kryten> <20141105102645.GA3046@hawk.usersys.redhat.com> <20150121143942.1549e9c9@kryten> <20150121105251.GA3040@hawk.usersys.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150121105251.GA3040@hawk.usersys.redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 21, 2015 at 11:52:51AM +0100, Andrew Jones wrote: > On Wed, Jan 21, 2015 at 02:39:42PM +1100, Anton Blanchard wrote: > > Hi Andrew, > > > > > On Wed, Nov 05, 2014 at 09:34:20AM +1100, Anton Blanchard wrote: > > > > commit 9919e39a1738 ("kvm: ensure hard lockup detection is disabled > > > > by default") provided a way for the kernel to disable the hard > > > > lockup detector at runtime. > > > > > > > > I'm using it on ppc64 but notice some weird behaviour with the > > > > nmi_watchdog procfs variable. At boot, that the hard lockup > > > > detector appears to be enabled even when we disable it via > > > > watchdog_enable_hardlockup_detector(false): > > > > > > > > # cat /proc/sys/kernel/nmi_watchdog > > > > 1 > > > > > > > > I have to echo 0 to it then echo 1 again to enable it. > > > > > > > > Anton > > > > > > Hi Anton, > > > > > > Yes, the nmi watchdog proc variables are currently a bit > > > confusing. Uli has posted a series to clear all that up > > > though. Please see > > > > > > https://lkml.org/lkml/2014/10/17/340 > > > > Any progress on this? I'm rebasing our hardware NMI patch for ppc64 and > > notice the strange behaviour is still in mainline. > > > > Hi Anton, > > I'm not aware of anything blocking this series, but maybe I missed > something. Andrew Morton and Don Zickus are the ones to ask. Andrew? > Don? Hi Drew, I poked Andrew again. I believe he is the person who usually takes my patches in. Cheers, Don