From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754910AbZHYKfx (ORCPT ); Tue, 25 Aug 2009 06:35:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754697AbZHYKfw (ORCPT ); Tue, 25 Aug 2009 06:35:52 -0400 Received: from casper.infradead.org ([85.118.1.10]:39815 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752547AbZHYKfv (ORCPT ); Tue, 25 Aug 2009 06:35:51 -0400 Subject: Re: [PATCH 15/15] x86: Fix cpu_coregroup_mask to return correct cpumask on multi-node processors From: Peter Zijlstra To: Andreas Herrmann Cc: Ingo Molnar , linux-kernel@vger.kernel.org In-Reply-To: <20090825102409.GK20811@alberich.amd.com> References: <20090820131243.GO29327@alberich.amd.com> <20090820134604.GD29327@alberich.amd.com> <1251128176.7538.301.camel@twins> <20090825093101.GJ20811@alberich.amd.com> <1251194143.7538.1128.camel@twins> <20090825102409.GK20811@alberich.amd.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Tue, 25 Aug 2009 12:35:02 +0200 Message-Id: <1251196502.7538.1136.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2009-08-25 at 12:24 +0200, Andreas Herrmann wrote: > On Tue, Aug 25, 2009 at 11:55:43AM +0200, Peter Zijlstra wrote: > > On Tue, 2009-08-25 at 11:31 +0200, Andreas Herrmann wrote: > > > On Mon, Aug 24, 2009 at 05:36:16PM +0200, Peter Zijlstra wrote: > > > > On Thu, 2009-08-20 at 15:46 +0200, Andreas Herrmann wrote: > > > > > The correct mask that describes core-siblings of an processor > > > > > is topology_core_cpumask. See topology adapation patches, especially > > > > > http://marc.info/?l=linux-kernel&m=124964999608179 > > > > > > > > > > > > argh, violence, murder kill.. this is the worst possible hack and you're > > > > extending it :/ > > > > > > So this is the third code area > > > (besides sched_*_power_savings sysfs interface, and the __cpu_power fiddling) > > > that is crap, mess, a hack. > > > > > > Didn't know that I'd enter such a minefield when touching this code. ;-( > > > > Yeah, you're lucky that way ;-) Its been creaking for a while, and I've > > been making noises to the IBM people (who so far have been the main > > source of power saving patches) to clean this up, but now you trod onto > > all of it at once.. > > > > > What would be your perferred solution for the > > > core_cpumask/llc_shared_map stuff? Another domain level to get rid of > > > this function? > > > > Right, I'd like to see everything exposed as domain levels. > > > > > > numa-cluster > > numa > > socket > > in-socket-numa > > multi-core > > shared-cache > > core > > threads > > > > We currently have a fixed order of these things, but I think we should > > simply provide helpers for building the sd tree and let the arch code do > > that instead of exporting all these masks in a fixed order. > > > > Once we get the arch domain tree, we do degenerate stuff to cull all the > > trivial domains and fold SD flags. > > So any in-socket-numa is only going to haeppen with the arch-defined > domain tree. Well, we could see what it takes to make this work without that. I mean, this is just how I'd like to see it end up, doesn't mean we cannot work on it from multiple angles at the same time. > Now that this is settled you should throw away the > __build_sched_domains cleanup patches that are in tip. They won't be > of use when domain creation code is basically changed. I'm not sure that's needed, we can continue work on refactoring that. Small steps towards something better seems a better plan than a single large step.