From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992535AbXCWVYb (ORCPT ); Fri, 23 Mar 2007 17:24:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992573AbXCWVYb (ORCPT ); Fri, 23 Mar 2007 17:24:31 -0400 Received: from mail.kroah.org ([69.55.234.183]:40862 "EHLO perch.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992535AbXCWVYa (ORCPT ); Fri, 23 Mar 2007 17:24:30 -0400 Date: Fri, 23 Mar 2007 14:07:29 -0700 From: Greg KH To: Mitch Williams Cc: linux-kernel@vger.kernel.org, mingo@redhat.com, auke-jan.h.kok@intel.com, john.ronciak@intel.com, jesse.brandeburg@intel.com Subject: Re: [PATCH 2.6.20.3] Flush writes to MSI-X table Message-ID: <20070323210729.GC12182@suse.de> References: <1174597699.24177.32.camel@strongmad> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1174597699.24177.32.camel@strongmad> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 22, 2007 at 02:08:19PM -0700, Mitch Williams wrote: > Because both MSI-X interrupt messages and MSI-X table writes are posted, > it's possible for them to cross while in-flight. This results in > interrupts being received long after the kernel thinks they're disabled, > and in interrupts being sent to stale vectors after rebalancing. > > This patch performs a read flush after writes to the MSI-X table for > enable/disable and rebalancing operations. Because this is an expensive > operation, we do not perform the read flush after mask/unmask > operations. Hardware which supports MSI-X typically also supports some > sort of interrupt moderation, so a read-flush is not necessary for > mask/unmask operations. > > This patch has been validated with (unreleased) network hardware which > uses MSI-X. Is this needed for any hardware that is public today? Also, it seems a bit too big of a patch for -stable right now, especially as the mainline patch will not make it into 2.6.22 at the earliest. thanks, greg k-h