From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764477AbXGKNQy (ORCPT ); Wed, 11 Jul 2007 09:16:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761371AbXGKNQq (ORCPT ); Wed, 11 Jul 2007 09:16:46 -0400 Received: from rwcrmhc13.comcast.net ([204.127.192.83]:38147 "EHLO rwcrmhc13.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760344AbXGKNQq (ORCPT ); Wed, 11 Jul 2007 09:16:46 -0400 From: Jeremy Maitin-Shepard To: Nigel Cunningham Cc: Miklos Szeredi , rjw@sisk.pl, a1426z@gawab.com, jeremy@goop.org, pavel@ucw.cz, nickpiggin@yahoo.com.au, linux-kernel@vger.kernel.org, akpm@linux-foundation.org Subject: Re: Hibernation Redesign In-Reply-To: <200707112211.23420.nigel@nigel.suspend2.net> (Nigel Cunningham's message of "Wed\, 11 Jul 2007 22\:11\:22 +1000") References: <200707081737.21932.a1426z@gawab.com> <200707111304.40504.rjw@sisk.pl> <200707112211.23420.nigel@nigel.suspend2.net> User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/22.0.990 (gnu/linux) X-Habeas-SWE-9: mark in spam to . X-Habeas-SWE-8: Message (HCM) and not spam. Please report use of this X-Habeas-SWE-7: warrant mark warrants that this is a Habeas Compliant X-Habeas-SWE-6: email in exchange for a license for this Habeas X-Habeas-SWE-5: Sender Warranted Email (SWE) (tm). The sender of this X-Habeas-SWE-4: Copyright 2002 Habeas (tm) X-Habeas-SWE-3: like Habeas SWE (tm) X-Habeas-SWE-2: brightly anticipated X-Habeas-SWE-1: winter into spring Date: Wed, 11 Jul 2007 09:16:41 -0400 Message-ID: <87644rcc7a.fsf@jbms.ath.cx> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Nigel Cunningham writes: [snip] > No other _proper_ solutions have been proposed. Everyone who suggests removing > the freezer also suggests implementing it all over again. It might be sending > SIGSTOP to everything. It might be shifting the desk chairs around and > creating a completely new kernel context, but they always have the same > goal - stopping the existing activity, and they all come with their own > issues (even if they're not obvious yet because the alternatives are > currently vapourware to one extent or another). I'll certainly admit the kexec idea is vaporware currently, but it does differ in a significant way from freezer-based approaches, such that I don't think it should be referred to as just another implementation of a freezer. Specifically, it doesn't require that the "old kernel" be in a "consistent" state to a greater extent than suspend to ram; it is the case that all of the devices must be quiesced or shut down to some extent, but doing this without races and deadlocks (and without the freezer) is certainly very, very similar to what needs to be done for suspend to ram, which will need to be solved anyway. Unlike the existing hibernate approaches, however, it will not be necessary to use any of the driver infrastructure once switched to the "save image" kernel, and thus it will not matter what locks are held, for instance. [snip] -- Jeremy Maitin-Shepard