From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761485Ab2COOgb (ORCPT ); Thu, 15 Mar 2012 10:36:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43664 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761209Ab2COOg3 (ORCPT ); Thu, 15 Mar 2012 10:36:29 -0400 Date: Thu, 15 Mar 2012 10:35:49 -0400 From: Don Zickus To: Peter Zijlstra Cc: Ingo Molnar , Mandeep Singh Baines , Andrew Morton , LKML , Michal Hocko Subject: Re: [PATCH] watchdog: Make sure the watchdog thread gets CPU on loaded system Message-ID: <20120315143549.GC3941@redhat.com> References: <1331757525-5755-1-git-send-email-dzickus@redhat.com> <20120314161906.e53359d3.akpm@linux-foundation.org> <20120315014511.GT27051@google.com> <1331809239.18960.168.camel@twins> <1331809597.18960.171.camel@twins> <20120315124228.GA5318@elte.hu> <1331820051.18960.187.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1331820051.18960.187.camel@twins> 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 Thu, Mar 15, 2012 at 03:00:51PM +0100, Peter Zijlstra wrote: > On Thu, 2012-03-15 at 13:42 +0100, Ingo Molnar wrote: > > So unless there's concensus to remove everything but the hard > > lockup detection facilities, lets solve the technical problem at > > hand, ok? > > Well, at least make it possible to disable the silly soft thing. > > And I really wouldn't know how the soft thing could possible help, > except when not actually having a NMI watchdog. What case does it > trigger where the NMI one doesn't? I think softlockup really boils down to a pre-emption disabled detector much like how the hardlockup really is a interrupts disabled detector. The amount of code preventing the scheduler from running is most likely a lot lower than the code the prevents interrrupts from happening. Cheers, Don