From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937576Ab0CPIZe (ORCPT ); Tue, 16 Mar 2010 04:25:34 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:34454 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936515Ab0CPIZc (ORCPT ); Tue, 16 Mar 2010 04:25:32 -0400 Date: Tue, 16 Mar 2010 09:25:07 +0100 From: Ingo Molnar To: Pekka Enberg Cc: Alexey Dobriyan , Tejun Heo , Linus Torvalds , Andrew Morton , lkml , Lee Schermerhorn , Christoph Lameter Subject: Re: [RFC] remove implicit slab.h inclusion from percpu.h Message-ID: <20100316082507.GG18448@elte.hu> References: <4B990496.4020002@kernel.org> <4B9F08AC.9030904@kernel.org> <20100316061718.GA22651@elte.hu> <84144f021003152358r41a79ccaxb18cf6368911266@mail.gmail.com> <4B9F39BE.40502@cs.helsinki.fi> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4B9F39BE.40502@cs.helsinki.fi> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: 0.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=0.0 required=5.9 tests=none autolearn=no SpamAssassin version=3.2.5 _SUMMARY_ Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Pekka Enberg wrote: > Alexey Dobriyan kirjoitti: > >On Tue, Mar 16, 2010 at 8:58 AM, Pekka Enberg wrote: > >> We should avoid creating tree-wide breakage for this kind of cleanups. > > > > This is done by compile testing, not by being smartass. > > I don't think compile testing is going to scale here because slab is used is > so many places of the kernel. Yes. In large-scale conversions i typically used (rather extensive) build-testing as a tool to check a script's correctness - distinctly _not_ to create the actual patch itself. I.e. it's an adaptive feedback loop in essence: the script gets perfected by repeated build tests, and the end result is that we have a scripted conversion that covers more code than build testing is able to reach (it covers not just x86, covers rare config combos, etc.), _plus_ we also have the final proof of the pudding via the actual build tests. In the end it all converges nicely and the build breakage exported is minimal. That is the mechanism i suggested. Alexey calls it 'smartass', i call it a defensive approach to large-scale changes, that we should practice more, not less. [ Or, sometimes, for visibly trivial matters i just take the gamble, go into cowboy mode and say 'to the heck, let others find those bugs' and do a change based on a sed -i oneliner and build a few configs, fix up the breakages it finds and hope for the best. I dont complain when i get slapped for that though ;-) ] Ingo