From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933094AbXEDPVh (ORCPT ); Fri, 4 May 2007 11:21:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933100AbXEDPVh (ORCPT ); Fri, 4 May 2007 11:21:37 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:43775 "EHLO ebiederm.dsl.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933094AbXEDPVg (ORCPT ); Fri, 4 May 2007 11:21:36 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Jeremy Fitzhardinge Cc: Rusty Russell , Andi Kleen , Chris Wright , Zachary Amsden , Andrew Morton , Linus Torvalds , "H. Peter Anvin" , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Revert "[PATCH] paravirt: Add startup infrastructure for paravirtualization" References: <1178280770.23670.61.camel@localhost.localdomain> <463B4A69.6020203@goop.org> Date: Fri, 04 May 2007 09:20:24 -0600 In-Reply-To: <463B4A69.6020203@goop.org> (Jeremy Fitzhardinge's message of "Fri, 04 May 2007 07:59:53 -0700") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jeremy Fitzhardinge writes: > Eric W. Biederman wrote: >> It's not theatrical. It makes this code path extremely brittle and >> very hard to change, which over the long term means that it is >> impossible to maintain. Quickly resulting in a state where any little >> change will break something. > > Removing the code now is premature. I'm presuming you're proposing this > as a .23 change, since we're planning on changing the paravirt boot to > make use of bzImage and the boot protocol then anyway. .22 and possibly -stable. -stable doesn't really matter because it is dead code. > The world isn't going to fall apart if its in there for a couple of months. As long as the code remains dead and unused I don't really care when we purge it. That code should NEVER EVER be used. That code is UNMAINTAINABLE. The code encourages random ABIs so we don't even know what we are supporting. Once used in a production environment (i.e. where we have to support it) it makes further changes to head.S essentially impossible. Despite the lack of Documentation we not counting the paravirt mess in head.S we have a well defined ABI for starting a linux-kernel. Given the generally difficulty of changing bootloaders I have no interesting is messing up a good thing. Eric