Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755642AbXJ1Sd1 (ORCPT ); Sun, 28 Oct 2007 14:33:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751850AbXJ1SdT (ORCPT ); Sun, 28 Oct 2007 14:33:19 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:48538 "EHLO ebiederm.dsl.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750952AbXJ1SdS (ORCPT ); Sun, 28 Oct 2007 14:33:18 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Adrian Bunk Cc: Jeremy Fitzhardinge , Kir Kolyshkin , containers@lists.osdl.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, kir@openvz.org Subject: Re: [Devel] [PATCH] pidns: Place under CONFIG_EXPERIMENTAL (take 2) References: <20071027002448.GH30533@stusta.de> <4724B4F2.7070500@goop.org> <20071028170008.GD7227@stusta.de> Date: Sun, 28 Oct 2007 12:31:30 -0600 In-Reply-To: <20071028170008.GD7227@stusta.de> (Adrian Bunk's message of "Sun, 28 Oct 2007 18:00:08 +0100") 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 Content-Length: 2106 Lines: 46 Adrian Bunk writes: > On Sun, Oct 28, 2007 at 09:12:34AM -0700, Jeremy Fitzhardinge wrote: >> Eric W. Biederman wrote: >> > Roughly that sounds like CONFIG_EXPERIMENTAL to me. But I would >> > be happy to hear if someone has a better idea. >> >> Rather than overload an existing config option, why not add one with the >> specific semantics you want: CONFIG_UNSTABLE_UABI. The problem seems >> like one which which may occur again, though one hopes not too often. I >> guess the risk is that people will leave their subsystems depending on >> it permanently (sysfs?), so it ends up being set all the time and >> becomes as useless as EXPERIMENTAL... > > Then let SYSFS depend on UNSTABLE_UABI for the next 10 years and we have > an excuse for breaking the ABI with each new kernel... > > Either the ABI is stable or it should not be exposed to users at all. If we need a new config for it. CONFIG_IMMATURE is the closest I can think of. Horrible ABI damage like reassigning magic numbers won't happen. Argument passing won't change (unless it is simply impossible). However there are little details which might change. Things like error codes or the behavior in unlikely circumstances. Bugs are expected to exist and so we bug compatibility isn't expect to be maintained. The bottom line is that when things are new they are immature and very rarely do they come out of the gate perfect. That is something we need to recognize and deal with. We need to communicate this to our users (distros and other developers) and we need to work quickly to get the kinks out so that the code really is mature. I'm not looking for excuses to mess up or do the wrong thing. I just know that as an engineer getting it perfect out of the gate isn't going to happen. So I'm doing what I can to ask people to ease into using something new. Eric - 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/