From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752611AbZB1Gwh (ORCPT ); Sat, 28 Feb 2009 01:52:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751266AbZB1Gw2 (ORCPT ); Sat, 28 Feb 2009 01:52:28 -0500 Received: from gw.goop.org ([64.81.55.164]:34030 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750942AbZB1Gw1 (ORCPT ); Sat, 28 Feb 2009 01:52:27 -0500 Message-ID: <49A8DF28.4050301@goop.org> Date: Fri, 27 Feb 2009 22:52:24 -0800 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.19 (X11/20090105) MIME-Version: 1.0 To: Andrew Morton CC: "H. Peter Anvin" , the arch/x86 maintainers , Linux Kernel Mailing List , Xen-devel Subject: Re: [PATCH] xen: core dom0 support References: <1235786365-17744-1-git-send-email-jeremy@goop.org> <20090227212812.26d02f34.akpm@linux-foundation.org> In-Reply-To: <20090227212812.26d02f34.akpm@linux-foundation.org> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: > On Fri, 27 Feb 2009 17:59:06 -0800 Jeremy Fitzhardinge wrote: > > >> This series implements the core parts of Xen dom0 support; that is, just >> enough to get the kernel started when booted by Xen as a dom0 kernel. >> > > And what other patches can we expect to see to complete the xen dom0 > support? > There's a bit of a gradient. There's probably another 2-3 similarly sized series to get everything so that you can boot dom0 out of the box (core, apic, swiotlb/agp/drm, backend drivers, tools). And then a scattering of smaller things which may or may not be upstreamable. The vast majority of it is Xen-specific code, rather than changes to core kernel. I'm in no particular rush to get it all into the kernel, but I would like to get the core parts in for .30 so that its basically useful, and the delta to feature-complete isn't very large (a big reason is to keep the out-of-tree patch size down for distros). > I hate to be the one to say it, but we should sit down and work out > whether it is justifiable to merge any of this into Linux. I think > it's still the case that the Xen technology is the "old" way and that > the world is moving off in the "new" direction, KVM? > I don't think that's a particularly useful way to look at it. They're different approaches to the problem, and have different tradeoffs. The more important question is: are there real users for this stuff? Does not merging it cause more net disadvantage than merging it? Despite all the noise made about kvm in kernel circles, Xen has a large and growing installed base. At the moment its all running on massive out-of-tree patches, which doesn't make anyone happy. It's best that it be in the mainline kernel. You know, like we argue for everything else. > In three years time, will we regret having merged this? > Its a pretty minor amount of extra stuff on top of what's been added over the last 3 years, so I don't think it's going to tip the scales on its own. I wouldn't be comfortable in trying to merge something that's very intrusive. J