Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263082AbTKTWxL (ORCPT ); Thu, 20 Nov 2003 17:53:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263060AbTKTWxK (ORCPT ); Thu, 20 Nov 2003 17:53:10 -0500 Received: from smtp2.clear.net.nz ([203.97.37.27]:14292 "EHLO smtp2.clear.net.nz") by vger.kernel.org with ESMTP id S263082AbTKTWxH (ORCPT ); Thu, 20 Nov 2003 17:53:07 -0500 Date: Fri, 21 Nov 2003 11:41:23 +1300 From: Nigel Cunningham Subject: Re: Patrick's Test9 suspend code. In-reply-to: <200311202233.09609.srhaque@iee.org> To: Shaheed Cc: rob@landley.net, Linux Kernel Mailing List Message-id: <1069368082.2239.66.camel@laptop-linux> MIME-version: 1.0 X-Mailer: Ximian Evolution 1.4.4-8mdk Content-type: text/plain Content-transfer-encoding: 7bit References: <200311201726.48097.srhaque@iee.org> <200311201339.45461.rob@landley.net> <200311202233.09609.srhaque@iee.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1575 Lines: 38 Hi. On Fri, 2003-11-21 at 11:33, Shaheed wrote: > Understood. But by definition, there must be at least one page of data on the > filesystem whose location we know in order to do the resume. Why can't we > simply use one extra page to store this data? Your reading of how the image is stored is correct, but it's not the real issue, I'm afraid. The question is more, why would you want this data. It doesn't make sense to boot from one kernel, suspend, boot from another kernel, suspend and then boot from the original kernel _unless_ in all of these cases, all filesystems are mounted read-only. If they're not mounted read-only, you'll get the cross linking and corruption Rob spoke of. Whenever I switch from testing a 2.4 kernel to testing 2.6, I do a clean boot for precisely this reason. I'd love it if I could just suspend 2.4, boot the new 2.6 kernel, see if it suspends properly (to a different swap, of course) and then resume the original 2.4 kernel. But doing so would only work if I mounted 2.6 entirely read only, which is not what you seem to be planning. Regards, Nigel -- Nigel Cunningham 495 St Georges Road South, Hastings 4201, New Zealand Evolution (n): A hypothetical process whereby infinitely improbable events occur with alarming frequency, order arises from chaos, and no one is given credit. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/