From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760338AbXGEMWR (ORCPT ); Thu, 5 Jul 2007 08:22:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756550AbXGEMWG (ORCPT ); Thu, 5 Jul 2007 08:22:06 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:53205 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755742AbXGEMWF (ORCPT ); Thu, 5 Jul 2007 08:22:05 -0400 From: "Rafael J. Wysocki" To: Paul Mackerras Subject: Re: [linux-pm] [PATCH] Remove process freezer from suspend to RAM pathway Date: Thu, 5 Jul 2007 14:29:06 +0200 User-Agent: KMail/1.9.5 Cc: Oliver Neukum , Miklos Szeredi , mjg59@srcf.ucam.org, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <20070703211227.GA28758@srcf.ucam.org> <200707041717.05149.rjw@sisk.pl> <18060.15209.274437.471074@cargo.ozlabs.ibm.com> In-Reply-To: <18060.15209.274437.471074@cargo.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200707051429.07535.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thursday, 5 July 2007 02:29, Paul Mackerras wrote: > Rafael J. Wysocki writes: > > > They will not trigger 100% of the time, but sporadically and generally at > > random. > > > > At least the freezer problems are reproducible. ;-) > > Our experience with powermacs has been that it isn't actually all that > hard to get it right for the drivers you care about. Well, I'm a bit suspicious about that. ;-) Namely, if you run your suspend code on one CPU and (do I remeber correctly that?) with kernel preemption disabled, then you practically prevent user land processes from being scheduled when your suspend code is running. If that is the case (of which I'm not sure), the freezer is obviously unnecessary, because you've taken processes out of the equation in a different way ... Greetings, Rafael -- "Premature optimization is the root of all evil." - Donald Knuth