From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934133AbXGKXNe (ORCPT ); Wed, 11 Jul 2007 19:13:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763942AbXGKXN1 (ORCPT ); Wed, 11 Jul 2007 19:13:27 -0400 Received: from [212.12.190.228] ([212.12.190.228]:33052 "EHLO raad.intranet" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1763656AbXGKXN0 (ORCPT ); Wed, 11 Jul 2007 19:13:26 -0400 From: Al Boldi To: "Rafael J. Wysocki" Subject: Re: Hibernation Redesign Date: Thu, 12 Jul 2007 02:12:24 +0300 User-Agent: KMail/1.5 Cc: Mark Lord , Jeremy Maitin-Shepard , Nigel Cunningham , Miklos Szeredi , jeremy@goop.org, pavel@ucw.cz, nickpiggin@yahoo.com.au, linux-kernel@vger.kernel.org, akpm@linux-foundation.org References: <200707081737.21932.a1426z@gawab.com> <200707120117.24549.a1426z@gawab.com> <200707120034.14201.rjw@sisk.pl> In-Reply-To: <200707120034.14201.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200707120212.24072.a1426z@gawab.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Rafael J. Wysocki wrote: > On Thursday, 12 July 2007 00:17, Al Boldi wrote: > > Mark Lord wrote: > > > Jeremy Maitin-Shepard wrote: > > > > I'll certainly admit the kexec idea is vaporware currently, > > > > Your idea is starting to become a reality with this thread: > > "[PATCH 0/2] Kexec jump: The first step to kexec base hibernation" > > > > > > 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. > > > > > > I really doubt that kexec(a special kernel) is going to solve anything > > > here. The new kernel will have to initialize, probe for devices, etc. > > > Which will take time. > > > Which will slow down hibernate to an unacceptable degree. > > > Right now, it (TuxOnIce) is *very* fast. > > > Adding 10 seconds or so for reprobing/resetting/reiniting devices > > > is not going to be useful. > > > And modifying all of the drivers to *not* do their usual probe > > > sequence sounds rather intrusive and is likely also a non-starter > > > here. > > > > > > Or is it? > > > > Well, it's definitely less intrusive than readying drivers for the > > freezer. > > There's nothing like this! Are you sure? # grep -i freeze drivers/*/* | wc -l gives: 297 Maybe you can clarify? Thanks! -- Al