From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262073AbTEACJH (ORCPT ); Wed, 30 Apr 2003 22:09:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262090AbTEACJH (ORCPT ); Wed, 30 Apr 2003 22:09:07 -0400 Received: from [12.47.58.20] ([12.47.58.20]:22663 "EHLO pao-ex01.pao.digeo.com") by vger.kernel.org with ESMTP id S262073AbTEACJB (ORCPT ); Wed, 30 Apr 2003 22:09:01 -0400 Date: Wed, 30 Apr 2003 19:22:05 -0700 From: Andrew Morton To: Keith Mannthey Cc: linux-kernel@vger.kernel.org Subject: Re: [RFC] clustered apic irq affinity fix for i386 Message-Id: <20030430192205.13491d61.akpm@digeo.com> In-Reply-To: <1051751157.16886.91.camel@dyn9-47-17-180.beaverton.ibm.com> References: <1051744032.16886.80.camel@dyn9-47-17-180.beaverton.ibm.com> <20030430163637.04f06ba6.akpm@digeo.com> <1051751157.16886.91.camel@dyn9-47-17-180.beaverton.ibm.com> X-Mailer: Sylpheed version 0.8.11 (GTK+ 1.2.10; i586-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 01 May 2003 02:21:15.0921 (UTC) FILETIME=[57C82810:01C30F88] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Keith Mannthey wrote: > > This should be better. Thanks for the comments. Remind me again what the patch actually does? It seems to be purely adding debug checks? Won't it just go BUG if someone boots the kernel and then tries to manually set affinity? Seems a bit racy too. setup_ioapic_dest() does: pending_irq_balance_apicid[irq] = mask; ==> window here set_ioapic_affinity(irq, mask); ioapic_lock is not held, so there is a window where pending_irq_balance_apicid[irq] can be set to some other value and io_apic_write_affinity() will accidentally go BUG. Is it not possible to fix set_ioapic_affinity() for real for clustered APIC mode? What is involved in that?