From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030387AbXCFWZK (ORCPT ); Tue, 6 Mar 2007 17:25:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030391AbXCFWZK (ORCPT ); Tue, 6 Mar 2007 17:25:10 -0500 Received: from nigel.suspend2.net ([203.171.70.205]:59002 "EHLO nigel.suspend2.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030387AbXCFWZI (ORCPT ); Tue, 6 Mar 2007 17:25:08 -0500 Subject: Re: Problem with freezable workqueues From: Nigel Cunningham Reply-To: nigel@nigel.suspend2.net To: "Rafael J. Wysocki" Cc: Johannes Berg , Pavel Machek , Gautham R Shenoy , LKML , Oleg Nesterov , Srivatsa Vaddagiri In-Reply-To: <200703062131.23465.rjw@sisk.pl> References: <200702272251.28844.rjw@sisk.pl> <1173141019.15891.39.camel@johannes.berg> <200703062131.23465.rjw@sisk.pl> Content-Type: text/plain Date: Wed, 07 Mar 2007 09:25:07 +1100 Message-Id: <1173219907.3219.37.camel@nigel.suspend2.net> Mime-Version: 1.0 X-Mailer: Evolution 2.9.92 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi. On Tue, 2007-03-06 at 21:31 +0100, Rafael J. Wysocki wrote: > Hi, > > On Tuesday, 6 March 2007 01:30, Johannes Berg wrote: > > On Tue, 2007-02-27 at 22:51 +0100, Rafael J. Wysocki wrote: > > > > > For 2.6.21-rc1 I've invented the appended workaround (works for me, waiting for > > > Johannes to confirm it works for him too), but I think we need something better > > > for -mm and future kernels. > > > > Finally I could get back to this but after reading the thread I figured > > it might not be necessary to test this. Please let me know ASAP if you > > want this patch tested as well or it'll take quite a long time (going > > skiing for a week on Saturday) > > I think it won't be necessary. > > For now, we have decided to make the workqueues nonfreezable (the patch for > that has already been merged, AFAICT). > > > In any case, I made the two xfs workqueues non-freezable and everything > > on my quad powermac works again, I also couldn't detect any filesystem > > correction. > > Good, thanks for the confirmation. > > > I wanted to adapt the BUG_ON(block IO not from suspend code) > > patch from suspend2 but haven't gotten around to it yet. > > That might be a good idea for other reasons too, but I'd prefer WARN_ON() > instead of BUG_ON() when you're at it. ;-) I made it BUG_ON() because if Suspend2 is running any I/O coming from another source besides Suspend2 may be I/O on a page that's been used for the atomic copy, and in that case it would definitely be bad to write it to disk. If swsusp is running, the BUG_ON() won't trigger IIRC. Regards, Nigel