From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755310AbXD0EwO (ORCPT ); Fri, 27 Apr 2007 00:52:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755312AbXD0EwO (ORCPT ); Fri, 27 Apr 2007 00:52:14 -0400 Received: from courier.cs.helsinki.fi ([128.214.9.1]:40816 "EHLO mail.cs.helsinki.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755310AbXD0EwN (ORCPT ); Fri, 27 Apr 2007 00:52:13 -0400 Date: Fri, 27 Apr 2007 07:52:11 +0300 (EEST) From: Pekka J Enberg To: Nigel Cunningham cc: Linus Torvalds , LKML Subject: Re: Back to the future. In-Reply-To: <1177617379.4737.29.camel@nigel.suspend2.net> Message-ID: References: <1177567481.5025.211.camel@nigel.suspend2.net> <84144f020704260028q190fc90fs8f9ea703e42e7910@mail.gmail.com> <1177573348.5025.224.camel@nigel.suspend2.net> <1177617379.4737.29.camel@nigel.suspend2.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2007-04-26 at 09:56 -0700, Linus Torvalds wrote: > > which will map in the snapshot, return the mapped address and the size > > (and if you want to support snapshots > 4GB, be my guest, but I suspect > > you're actually *better* off just admitting that if you cannot shrink > > the snapshot to less than 32 bits, it's not worth doing) On Fri, 27 Apr 2007, Nigel Cunningham wrote: > That inherently limits the image to half of available ram (you need > somewhere to store the snapshot), so you won't get the full image you > express interest in below. It doesn't. We can make the userspace mapped pages copy-on-write. As long as the userspace makes sure there's not much activity during snapshot/shutdown, we will be fine. What we probably do need to copy is kernel pages. Pekka