From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:46796) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ROPO3-0001Sz-Jn for qemu-devel@nongnu.org; Thu, 10 Nov 2011 02:49:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ROPO2-0003cy-GI for qemu-devel@nongnu.org; Thu, 10 Nov 2011 02:49:27 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:54464) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ROPO2-0003cl-69 for qemu-devel@nongnu.org; Thu, 10 Nov 2011 02:49:26 -0500 Date: Thu, 10 Nov 2011 08:47:28 +0100 From: Ingo Molnar Message-ID: <20111110074728.GA12768@elte.hu> References: <20111106231953.GD4500@thunk.org> <20111107203255.GF24234@thunk.org> <4EB85969.2010108@codemonkey.ws> <12F471C8-2CF3-4CD7-B417-C8CC898669E6@mit.edu> <20111108093225.GB32533@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Subject: Re: [Qemu-devel] [F.A.Q.] the advantages of a shared tool/kernel Git repository, tools/perf/ and tools/kvm/ List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?iso-8859-1?Q?Am=E9rico?= Wang Cc: Alexander Graf , Theodore Tso , Peter Zijlstra , "kvm@vger.kernel.org list" , qemu-devel Developers , Vince Weaver , "linux-kernel@vger.kernel.org List" , Pekka Enberg , Blue Swirl , Arnaldo Carvalho de Melo , Avi Kivity , Thomas Gleixner , Linus Torvalds * Américo Wang wrote: > On Tue, Nov 8, 2011 at 5:32 PM, Ingo Molnar wrote: > > > > So i think you should seriously consider moving your projects > > *into* tools/ instead of trying to get other projects to move out > > ... > > > > You should at least *try* the unified model before criticising it > > - because currently you guys are preaching about sex while having > > sworn a life long celibacy ;-) > > Ingo, this is making Linux another BSD... manage everything in a > single tree... It's not an all-or-nothing prospect. Linux user-space consists of well in excess of 200 MLOC code. The kernel is 15 MLOC. I think the system-bound utilities that 'obviously' qualify for kernel inclusion are around 1 MLOC in total size, i.e. less than 0.5% of all user-space. > Also, what is your criteria for merging a user-space project into > kernel tree? Well, my criteria go roughly along these lines: 1) The developers use that model and are productive that way and produce a tool that has a significant upside. 2) There's significant Linux-specific interactions between the user-space project and the kernel. 3) The code is clean, well designed and follows the various principles laid out in Documentation/CodingStyle and Documentation/ManagementStyle so that it can be merged into a prominent spot in the kernel tree and the project is ready to live with the (non-trivial!) consequences of all that: - the project does -stable kernel backports of serious bugs - the project follows a strict "no regressions" policy - the project follows the kernel release cycle of 'Winter', 'Spring', 'Summer' and 'Autumn' releases and follows the merge window requirements and implements the post-rc1 stabilization cycle. These are not easy requirements and i can well imagine that many projects, even if they qualified on all other counts, would prefer to stay out of tree than be subject to such strict release engineering constraints. Also, the requirements can be made stricter with time, based on positive and negative experiences. Projects can 'die' and move out of the kernel as well if the kernel repo did not work out for them. As long as it's all done gradually and on a case by case basis Linux can only benefit from this. Thanks, Ingo