From owner-freebsd-hackers@FreeBSD.ORG Mon Jan 24 20:30:04 2005 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9673916A4CF for ; Mon, 24 Jan 2005 20:30:04 +0000 (GMT) Received: from ferengi.borderworlds.dk (ferengi.borderworlds.dk [80.166.152.7]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1C12943D1D for ; Mon, 24 Jan 2005 20:30:04 +0000 (GMT) (envelope-from xi@borderworlds.dk) Received: from borg.borderworlds.dk (localhost [127.0.0.1]) by ferengi.borderworlds.dk (Postfix) with ESMTP id 6BAC6B810; Mon, 24 Jan 2005 21:30:02 +0100 (CET) Received: by borg.borderworlds.dk (Postfix, from userid 1001) id 5F9F911425; Mon, 24 Jan 2005 21:30:02 +0100 (CET) Sender: xi@borderworlds.dk To: Dominic Marks References: <86pszu639o.fsf@borg.borderworlds.dk> <41F54F98.6050908@helenmarks.co.uk> From: Christian Laursen Date: 24 Jan 2005 21:30:01 +0100 In-Reply-To: <41F54F98.6050908@helenmarks.co.uk> Message-ID: <86brbe6052.fsf@borg.borderworlds.dk> Lines: 33 User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii cc: hackers@freebsd.org Subject: Re: Resuming from a crashdump X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 24 Jan 2005 20:30:04 -0000 Dominic Marks writes: > Christian Laursen wrote: > > I was thinking about software suspend and got this crazy idea. > > I have no idea if this is possible or total madness but here > > goes anyway. > > The idea would be to force the system to "crash" and make a > > dump on a dedicated partition. On boot after initializing devices > > but before mounting /, the kernel would check that partition and > > if it found a dump there restore it to the machine's memory, > > reinitialize devices and continue where it left off. > > As I understand it, you choose to panic at a point where you > have reached an unrecoverable state. So unless you had special > code to fix this (thats going to be an interesting challenge as > a programmer) you'd end up looping through the panic again and > again. I'm not interested in resuming after a real crash. The idea is to get suspend/resume functionality without hardware support. So there would be no panic, but the system would be brought to a halt and the memory dumped. > Also the devices wouldn't be in the state they had been in at > the time of the panic, so if you could get as far as the > reloaded kernel actualy doing anything, you'd either crash again > or risk corrupting things horribly. That's why they would have to be reinitialized. -- Christian Laursen