Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754516AbZFCTGE (ORCPT ); Wed, 3 Jun 2009 15:06:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753837AbZFCTFy (ORCPT ); Wed, 3 Jun 2009 15:05:54 -0400 Received: from THUNK.ORG ([69.25.196.29]:50857 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753626AbZFCTFy (ORCPT ); Wed, 3 Jun 2009 15:05:54 -0400 Date: Wed, 3 Jun 2009 15:05:21 -0400 From: Theodore Tso To: George Dunlap Cc: Steven Rostedt , Dan Magenheimer , Ingo Molnar , David Miller , "jeremy@goop.org" , "avi@redhat.com" , "xen-devel@lists.xensource.com" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , Keir Fraser , "torvalds@linux-foundation.org" , "gregkh@suse.de" , "kurt.hackel@oracle.com" , Ian Pratt , "xen-users@lists.xensource.com" , ksrinivasan , "EAnderson@novell.com" , "wimcoekaerts@wimmekes.net" , Stephen Spector , "jens.axboe@oracle.com" , "npiggin@suse.de" Subject: Re: Merge Xen (the hypervisor) into Linux Message-ID: <20090603190521.GJ31943@mit.edu> Mail-Followup-To: Theodore Tso , George Dunlap , Steven Rostedt , Dan Magenheimer , Ingo Molnar , David Miller , "jeremy@goop.org" , "avi@redhat.com" , "xen-devel@lists.xensource.com" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , Keir Fraser , "torvalds@linux-foundation.org" , "gregkh@suse.de" , "kurt.hackel@oracle.com" , Ian Pratt , "xen-users@lists.xensource.com" , ksrinivasan , "EAnderson@novell.com" , "wimcoekaerts@wimmekes.net" , Stephen Spector , "jens.axboe@oracle.com" , "npiggin@suse.de" References: <3ab07e3b-a601-48d5-b350-29cbaf111892@default> <4A2666A7.4060603@eu.citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A2666A7.4060603@eu.citrix.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@mit.edu X-SA-Exim-Scanned: No (on thunker.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1888 Lines: 34 On Wed, Jun 03, 2009 at 01:03:51PM +0100, George Dunlap wrote: > It is a very interesting idea, but it would still be basically a > completely new project. If someone started such a project, they could > probably cannibalize a lot of Xen's existing code (a funny boomerang, > since Xen cannibalized Linux's code when it started), but it would still > require a lot of work and re-writing, and the result would be a lot > different than Xen is now. It would be years before it was ready to be > used in a production system. You might be surprised; if we started with a working dom0/xen pair, and there were people working on it to clean up dom0/xen interface, treating it as an internal Linux interface with an eye towards minimizing contamination of core kernel code, the Linux model of development can go pretty fast. Compare and contrast it with the ***years*** of calendar time and decades of wasted man-years of engineering effort needed to port and backport and maintain dom0 support with Linux. Given that experience, I could easily see how some might assume that it would take years to significantly improve things, but I suspect if xen were merged into mainline with the assumption that it could be arbitrarily changed to make things sane, with the primary interface that needed backwards compatibility care being the xen/domU interface, I expect things would go pretty fast. What would be lost is dom0 support for other OS's, but really, is that such a major loss? Linux has far better device driver support than Solaris or FreeBSD, so there is really that much gain in using some other OS for dom0? - Ted -- 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/