Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760092AbXFBDtb (ORCPT ); Fri, 1 Jun 2007 23:49:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755861AbXFBDtX (ORCPT ); Fri, 1 Jun 2007 23:49:23 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:45358 "EHLO ebiederm.dsl.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755249AbXFBDtW (ORCPT ); Fri, 1 Jun 2007 23:49:22 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: "Darrick J. Wong" Cc: Emmanuel Fust? , linux-kernel Subject: Re: Device hang when offlining a CPU due to IRQ misrouting References: <20070602021906.GC13751@tree.beaverton.ibm.com> Date: Fri, 01 Jun 2007 21:48:25 -0600 In-Reply-To: <20070602021906.GC13751@tree.beaverton.ibm.com> (Darrick J. Wong's message of "Fri, 1 Jun 2007 19:19:07 -0700") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1400 Lines: 34 "Darrick J. Wong" writes: > On Fri, Jun 01, 2007 at 06:18:32PM -0600, Eric W. Biederman wrote: > >> I doubt it. The practical problem is that cpu_down does not >> and by design can not call the irq balancing part properly >> and I haven't yet seen anything to suggest that we don't migrate >> irq properly. >> >> So I'm guessing it was the decision part. > > I'm not using any IRQ balancer, afaik. As I recall, CONFIG_IRQBALANCE > is i386-only, and I'm not running the userland irqbalance program > either. Just messing around with /proc/irq/*/smp_affinity by hand. :) This is just getting confusing. Emmanuel Fust. Please play with /proc/irq/*/smp_affinity by hand and confirm that you can move your irqs. This will confirm it is the decision part. Darrick. The cpu hotplug architecture makes it impossible to properly call irq migration code that backs /proc/irq/*/smp_affinity. Therefore the cpu hotplug interface to irq migration is broken by design. There are some other bugs in the implementation of migrating irqs off of cpus as well. I'm pretty certain that some combination of those problems is biting you. Eric - 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/