Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756673AbZFDNVU (ORCPT ); Thu, 4 Jun 2009 09:21:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753151AbZFDNVK (ORCPT ); Thu, 4 Jun 2009 09:21:10 -0400 Received: from smtp.eu.citrix.com ([62.200.22.115]:18329 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751928AbZFDNVK (ORCPT ); Thu, 4 Jun 2009 09:21:10 -0400 X-IronPort-AV: E=Sophos;i="4.41,305,1241395200"; d="scan'208";a="5584469" Message-ID: <4A27CA44.3060604@eu.citrix.com> Date: Thu, 04 Jun 2009 14:21:08 +0100 From: George Dunlap User-Agent: Thunderbird 2.0.0.21 (X11/20090409) MIME-Version: 1.0 To: Frans Pop CC: Bill Davidsen , "tglx@linutronix.de" , "davem@davemloft.net" , "jeremy@goop.org" , "mingo@elte.hu" , Dan Magenheimer , "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" Subject: Re: Xen is a feature References: <162f4c90-6431-4a2a-b337-6d7451d7b11e@default> <20090528001350.GD26820@elte.hu> <4A1F302E.8030501@goop.org> <20090528.210559.137121893.davem@davemloft.net> <4A1FCE8E.2060604@eu.citrix.com> <4A26D3D8.6080002@tmr.com> <4A26FB3B.6010205@tmr.com> <200906040129.07852.elendil@planet.nl> In-Reply-To: <200906040129.07852.elendil@planet.nl> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 04 Jun 2009 13:21:10.0830 (UTC) FILETIME=[53B74CE0:01C9E517] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2185 Lines: 42 Frans Pop wrote: > ! The kernel policy always was and still is to accept only those > ! features which have a technical benefit **to the code base**. > Yes, I think I understood him better after I responded to his e-mail (unfortunately). When people say things like "dom0 adds all these hooks but doesn't add anything to Linux", they mean something like this (please correct me anyone, if I'm wrong). Kernel developers want Linux, as a project, to have cool things in it. They want it to be cool. Adding new features, new capabilities, new technical code, makes it cooler. Sometimes adding new features to make it cooler has some cost in terms of adding things to other parts of the code, possibly making it a little less clean or a little more convoluted. But if the coolness is cool enough, it's worth the cost. The feeling is that adding a bunch of these dom0 hooks (especially of the type, "if(xen) { foo; }"), are a cost to Linux. They make the code ugly. They do allow a new kind of coolness, a (linux-dom0 + Xen) coolness. But none of the coolness actually happens in Linux; it all happens in Xen. So coolness may happen, and world happiness might increase marginally, but Linux itself doesn't seem any cooler, it just has the cost of all these ugly hooks. Thus the "Linux is Xen's sex slave" analogy. :-) If (hypothetically) we merged Xen into Linux, then (people are suggesting) the coolness of Xen would actually contribute to the coolness of Linux ("add technical benefit to the code base"). People would feel like working on the interface between linux-xen and the rest of linux would be making their own piece of software, Linux, work better, rather than feeling like they have to work with some foreign project that doesn't make their code any cooler. Is that a pretty accurate representation of the "adding features which have a technical benefit to the code base" argument? -George -- 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/