Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758655AbYHUNRb (ORCPT ); Thu, 21 Aug 2008 09:17:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752857AbYHUNRY (ORCPT ); Thu, 21 Aug 2008 09:17:24 -0400 Received: from outbound-wa4.frontbridge.com ([216.32.181.16]:4183 "EHLO WA4EHSOBE005.bigfish.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753486AbYHUNRX (ORCPT ); Thu, 21 Aug 2008 09:17:23 -0400 X-BigFish: VPS-45(zz1432R98dR936eQ62a3L1805M936fQzz10d3izzz32i6bh62h) X-Spam-TCS-SCL: 1:0 X-FB-SS: 5, X-WSS-ID: 0K5YCWM-02-FU3-01 Date: Thu, 21 Aug 2008 15:16:52 +0200 From: Robert Richter To: Ingo Molnar CC: Jan Beulich , linux-kernel@vger.kernel.org Subject: Re: patch "x86: MOVE PCI IO ECS code to x86/pci" breaks CPU hotplug Message-ID: <20080821131652.GC13011@erda.amd.com> References: <48AD7F80.76E4.0078.0@novell.com> <20080821130259.GA22887@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20080821130259.GA22887@elte.hu> User-Agent: Mutt/1.5.16 (2007-06-09) X-OriginalArrivalTime: 21 Aug 2008 13:17:14.0006 (UTC) FILETIME=[3A009360:01C90390] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1988 Lines: 58 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. -Robert -- Advanced Micro Devices, Inc. Operating System Research Center email: robert.richter@amd.com -- 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/