From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756581AbXGKENT (ORCPT ); Wed, 11 Jul 2007 00:13:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751637AbXGKENK (ORCPT ); Wed, 11 Jul 2007 00:13:10 -0400 Received: from [212.12.190.99] ([212.12.190.99]:32826 "EHLO raad.intranet" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751598AbXGKENJ (ORCPT ); Wed, 11 Jul 2007 00:13:09 -0400 From: Al Boldi To: Jeremy Fitzhardinge , Jeremy Maitin-Shepard Subject: Re: Hibernation Redesign Date: Wed, 11 Jul 2007 07:11:26 +0300 User-Agent: KMail/1.5 Cc: Pavel Machek , Nick Piggin , linux-kernel@vger.kernel.org, Andrew Morton References: <200707081737.21932.a1426z@gawab.com> <871wfguq5g.fsf@jbms.ath.cx> <46940F45.3090005@goop.org> In-Reply-To: <46940F45.3090005@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200707110711.26767.a1426z@gawab.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jeremy Fitzhardinge wrote: > Jeremy Maitin-Shepard wrote: > > In > > addition, I recall that the Linux boot procedure on x86 and on some > > other platforms necessarily uses certain low-address memory, like the > > first 640K, which must be backed up regardless. > > Well, the traditional framebuffer/ISA space between 640k and 1M probably > needs to be identity mapped, but I don't think there's anything in there > which specifically needs to be save/restored (except framebuffer > contents, maybe?). > > > For these reasons, it seems that it would be easiest to simply backup > > the first e.g. 16 or 64 MB of memory, and not have to worry about > > loading the kernel at a non-standard address and specifying a > > complicated exact memmap. Someone might prove me wrong, though. > > Yes, I suppose. You're certain the old kernel's devices are completely > quiescent at that point? That's exactly the problem; trying to save a state from within the kernel would probably necessitate a freezer hack, which we are trying so dearly to avoid. The only way the kexec approach may be successful, is by completely relying on the kexec'd hibernate-mode kernel to save state, otherwise we would be back to square one. And if that required a special boot procedure for the kexec'd hibernate-mode kernel, then why not? Thanks! -- Al