From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758012AbZBXPPz (ORCPT ); Tue, 24 Feb 2009 10:15:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754154AbZBXPPr (ORCPT ); Tue, 24 Feb 2009 10:15:47 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:41796 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753860AbZBXPPq (ORCPT ); Tue, 24 Feb 2009 10:15:46 -0500 Date: Tue, 24 Feb 2009 16:15:12 +0100 From: Ingo Molnar To: Tejun Heo Cc: rusty@rustcorp.com.au, tglx@linutronix.de, x86@kernel.org, linux-kernel@vger.kernel.org, hpa@zytor.com, jeremy@goop.org, cpw@sgi.com, nickpiggin@yahoo.com.au, ink@jurassic.park.msu.ru Subject: Re: [PATCHSET x86/core/percpu] improve the first percpu chunk allocation Message-ID: <20090224151512.GA12438@elte.hu> References: <1235445101-7882-1-git-send-email-tj@kernel.org> <20090224095708.GA20739@elte.hu> <49A3DE76.5010606@kernel.org> <20090224124042.GA31295@elte.hu> <49A3F5C5.4060107@kernel.org> <20090224141217.GA17287@elte.hu> <49A40624.4000100@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49A40624.4000100@kernel.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Tejun Heo wrote: > > It's still about this restriction: > > > > + /* > > + * If large page isn't supported, there's no benefit in doing > > + * this. Also, embedding allocation doesn't play well with > > + * NUMA. > > + */ > > + if (!cpu_has_pse || pcpu_need_numa()) > > + return -EINVAL; > > > > This is what makes no sense (why force the static percpu area > > into 4K mappings on NUMA). > > No, the first allocator tried is remap allocator which will do > the 2MB remapping thing if NUMA. If not, it gives its way to > embedding allocator which only kicks in for pse && !numa. The > 4k thing is just the last resort. We might as well kill it > and make it > > if (numa) > do remap > else > do embed > panic if failed > > The 4k thing is the final fallback for cases where pse isn't > supported. ah, ok :-) Then i was confused by that and wanted to see something implemented that ... was already there :) Ingo