From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752778AbbBWVTt (ORCPT ); Mon, 23 Feb 2015 16:19:49 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:44955 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751861AbbBWVTs (ORCPT ); Mon, 23 Feb 2015 16:19:48 -0500 Date: Mon, 23 Feb 2015 13:19:46 -0800 From: Andrew Morton To: Don Zickus Cc: LKML , Ulrich Obergfell , Ingo Molnar Subject: Re: [PATCH 7/9] watchdog: enable the new user interface of the watchdog mechanism Message-Id: <20150223131946.599d3af2a361b4fd70df0edf@linux-foundation.org> In-Reply-To: <1423168825-156238-8-git-send-email-dzickus@redhat.com> References: <1423168825-156238-1-git-send-email-dzickus@redhat.com> <1423168825-156238-8-git-send-email-dzickus@redhat.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 5 Feb 2015 15:40:23 -0500 Don Zickus wrote: > From: Ulrich Obergfell > > With the current user interface of the watchdog mechanism it is only > possible to disable or enable both lockup detectors at the same time. > This series introduces new kernel parameters and changes the semantics > of some existing kernel parameters, so that the hard lockup detector > and the soft lockup detector can be disabled or enabled individually. > With this series applied, the user interface is as follows. > > - parameters in /proc/sys/kernel > > . soft_watchdog > This is a new parameter to control and examine the run state of > the soft lockup detector. > > . nmi_watchdog > The semantics of this parameter have changed. It can now be used > to control and examine the run state of the hard lockup detector. > > . watchdog > This parameter is still available to control the run state of both > lockup detectors at the same time. If this parameter is examined, > it shows the logical OR of soft_watchdog and nmi_watchdog. > > . watchdog_thresh > The semantics of this parameter are not affected by the patch. > > - kernel command line parameters > > . nosoftlockup > The semantics of this parameter have changed. It can now be used > to disable the soft lockup detector at boot time. > > . nmi_watchdog=0 or nmi_watchdog=1 > Disable or enable the hard lockup detector at boot time. The patch > introduces '=1' as a new option. > > . nowatchdog > The semantics of this parameter are not affected by the patch. It > is still available to disable both lockup detectors at boot time. So we need a whole bunch of updates and additions to Documentation/? Are all these changes back-compatible with previous kernel versions?