From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758212AbXGHWNd (ORCPT ); Sun, 8 Jul 2007 18:13:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757544AbXGHWN0 (ORCPT ); Sun, 8 Jul 2007 18:13:26 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:33479 "EHLO amd.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757309AbXGHWNZ (ORCPT ); Sun, 8 Jul 2007 18:13:25 -0400 Date: Mon, 9 Jul 2007 00:13:15 +0200 From: Pavel Machek To: Benjamin Herrenschmidt Cc: "Rafael J. Wysocki" , Alan Stern , Kyle Moffett , Nigel Cunningham , Matthew Garrett , linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org Subject: hibernation/snapshot design [was Re: [PATCH] Remove process freezer from suspend to RAM pathway] Message-ID: <20070708221315.GF5401@elf.ucw.cz> References: <200707082115.27363.rjw@sisk.pl> <1183928612.3388.289.camel@localhost.localdomain> <200707082345.27859.rjw@sisk.pl> <1183931688.3388.316.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1183931688.3388.316.camel@localhost.localdomain> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > Actaully, I'm perfectly fine with that, as long as each task blocked by the > > driver due to suspend has PF_FROZEN (or something similar) set. Then, at > > least theoretically, we'll be able to drop the freezer from the suspend code > > path and move it after device_suspend() (or the hibernation-specific > > equivalent) for hibernation (in that case there shouldn't be a problem with > > any task waiting on I/O while the freezer is running ;-)). > > I don't see the need for a freezer for snapshot but that's a different > issue. (stop_machine looks good enough to me). Freezer is not needed for snapshot -- it is needed so that we can write out the snapshot to disk without the need for special drivers/block/simple-ide-for-suspend.c. (We are doing snapshot, then write to disk from userland code in uswsusp). Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html