From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758536Ab0DPQOT (ORCPT ); Fri, 16 Apr 2010 12:14:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55970 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758511Ab0DPQOR (ORCPT ); Fri, 16 Apr 2010 12:14:17 -0400 Date: Fri, 16 Apr 2010 12:14:01 -0400 From: Don Zickus To: Frederic Weisbecker Cc: mingo@elte.hu, peterz@infradead.org, gorcunov@gmail.com, aris@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] [watchdog] combine nmi_watchdog and softlockup Message-ID: <20100416161401.GI15159@redhat.com> References: <1271366710-17468-1-git-send-email-dzickus@redhat.com> <20100416014712.GC15570@nowhere> <20100416141213.GC15159@redhat.com> <20100416144302.GB5162@nowhere> <20100416150407.GH15159@redhat.com> <20100416153210.GG5162@nowhere> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100416153210.GG5162@nowhere> User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 16, 2010 at 05:32:12PM +0200, Frederic Weisbecker wrote: > > I'll try to implement this. Any objections if I combined hardlockup and > > softlockup with per cpu watchdog_warn and have bit masks for HARDLOCKUP > > and SOFTLOCKUP? I hate to just waste per cpu space for this. > > > > Hmm, a hardlockup can come in after a softlockup. Let me re-explain what I meant. It was meant to do double duty. The softlockup code only checks the SOFTLOCKUP bit and the hardlockup only ever checks the HARDLOCKUP bit. ie if get_cpu_var(watchdog_warn) && HARDLOCKUP { return; } > Don't worry too much about memory: usually the more you have cpu, > the more you have memory :) > Plus this is debugging code, not something supposed to be enabled > in production. Well depends on your POV. In RHEL we enable both NMI_WATCHDOG and SOFTLOCKUP on production systems (and we have customers that are thankful for that :-) ). Cheers, Don