Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755875AbYHVGFr (ORCPT ); Fri, 22 Aug 2008 02:05:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752783AbYHVGFj (ORCPT ); Fri, 22 Aug 2008 02:05:39 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:57386 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752675AbYHVGFj (ORCPT ); Fri, 22 Aug 2008 02:05:39 -0400 Date: Fri, 22 Aug 2008 08:05:20 +0200 From: Ingo Molnar To: Robert Richter Cc: Jan Beulich , linux-kernel@vger.kernel.org, Yinghai Lu Subject: Re: patch "x86: MOVE PCI IO ECS code to x86/pci" breaks CPU hotplug Message-ID: <20080822060520.GG14110@elte.hu> References: <48AD7F80.76E4.0078.0@novell.com> <20080821130259.GA22887@elte.hu> <20080821131652.GC13011@erda.amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080821131652.GC13011@erda.amd.com> 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 Content-Length: 2151 Lines: 58 * Robert Richter wrote: > On 21.08.08 15:02:59, Ingo Molnar wrote: > > > > * Jan Beulich wrote: > > > > > Converting __cpuinit functions called out of init_amd() (and similar > > > others) to __init (and making them subject of xxx_initcall() handling > > > isn't valid, as they would no longer be called for hot plugged CPUs. > > > > > > Further, since it's likely that in virtualized environments the MSR > > > write would at best be ignored, I'd also recommend using the > > > fault-safe accessors here *and* check that the bit actually got set > > > before setting PCI_HAS_IO_ECS (one would obviously have to BUG() when > > > hot-plugged CPUs fail to set the bit when those available at boot > > > successfully did so). > > > > hm, which patch is this exactly, and in what tree? It's not upstream nor > > in -tip. > > Probably this in the mainline kernel is meant: > > commit 3a27dd1ce5de08e21e0266ddf00e6f1f843bfe8b > Author: Robert Richter > Date: Thu Jun 12 20:19:23 2008 +0200 > > x86: Move PCI IO ECS code to x86/pci > > "Form follows function". Code is now where it belongs to. > > Signed-off-by: Robert Richter > Signed-off-by: Ingo Molnar > > The problem is code like this: > > +static int __init enable_pci_io_ecs(void) > +{ > + /* assume all cpus from fam10h have IO ECS */ > + if (boot_cpu_data.x86 < 0x10) > + return 0; > + on_each_cpu(enable_pci_io_ecs_per_cpu, NULL, 1, 1); > + pci_probe |= PCI_HAS_IO_ECS; > + return 0; > +} > > It is only called during the setup and if the cpu is enabled. I intend > to rewrite the cpu setup code using cpu notifiers. ok. Unfortunately the revert looks quite non-trivial for v2.6.27. Could we have some _really_ minimal fix for v2.6.27? Ingo -- 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/