From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758674AbXGCRVR (ORCPT ); Tue, 3 Jul 2007 13:21:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754871AbXGCRVD (ORCPT ); Tue, 3 Jul 2007 13:21:03 -0400 Received: from smtp-out001.kontent.com ([81.88.40.215]:45189 "EHLO smtp-out.kontent.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754366AbXGCRVB (ORCPT ); Tue, 3 Jul 2007 13:21:01 -0400 From: Oliver Neukum To: "Rafael J. Wysocki" Subject: Re: [PATCH] Remove process freezer from suspend to RAM pathway Date: Tue, 3 Jul 2007 19:20:59 +0200 User-Agent: KMail/1.9.7 Cc: Benjamin Herrenschmidt , Matthew Garrett , linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org, Pavel Machek , Nigel Cunningham References: <20070703042916.GA17240@srcf.ucam.org> <200707031508.45595.rjw@sisk.pl> <200707031709.29968.rjw@sisk.pl> In-Reply-To: <200707031709.29968.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200707031920.59940.oliver@neukum.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Am Dienstag, 3. Juli 2007 schrieb Rafael J. Wysocki: > On Tuesday, 3 July 2007 15:08, Rafael J. Wysocki wrote: > > On Tuesday, 3 July 2007 07:51, Benjamin Herrenschmidt wrote: > > > On Tue, 2007-07-03 at 05:29 +0100, Matthew Garrett wrote: > > > > Suspend to RAM on a machine with / on a fuse filesystem turns out to be > > > > a screaming nightmare - either the suspend fails because syslog (for > > > > instance) can't be frozen, or the machine deadlocks for some other > > > > reason I haven't tracked down. We could "fix" fuse, or alternatively we > > > > could do what we do for suspend to RAM on other platforms (PPC and APM) > > > > and just not use the freezer. > > > > > > The main reason for deadlocks is because we do a sys_sync() after the > > > freeze, which we shouldn't do. > > > > So why don't we remove the sys_sync() from freeze_processes() instead? > > The patch follows (untested). > > Greetings, > Rafael > > > --- > From: Rafael J. Wysocki > > We shouldn't sync filesystems from within the freezer, because it's not needed > for suspend to RAM and leads to problems with FUSE. This seems fishy. Swsusp needs enough clean memory to make enough room for the image. If you sync before you freeze, the running tasks can redirty memory. What makes you sure that you don't die as shrink_all_memory() writes out pages? Regards Oliver