From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751952AbYHKE0s (ORCPT ); Mon, 11 Aug 2008 00:26:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750856AbYHKE0l (ORCPT ); Mon, 11 Aug 2008 00:26:41 -0400 Received: from gw.goop.org ([64.81.55.164]:33597 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750826AbYHKE0k (ORCPT ); Mon, 11 Aug 2008 00:26:40 -0400 Message-ID: <489FBF6A.40402@goop.org> Date: Sun, 10 Aug 2008 21:26:18 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.16 (X11/20080723) MIME-Version: 1.0 To: Nick Piggin CC: Venki Pallipadi , Jens Axboe , Ingo Molnar , npiggin@suse.de, linux-kernel , suresh.b.siddha@intel.com Subject: Re: [PATCH] stack and rcu interaction bug in smp_call_function_mask() References: <20080808193753.GA21964@linux-os.sc.intel.com> <200808101624.15112.nickpiggin@yahoo.com.au> In-Reply-To: <200808101624.15112.nickpiggin@yahoo.com.au> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Nick Piggin wrote: > Nice debugging work. > > I'd suggest something like the attached (untested) patch as the simple > fix for now. > > I expect the benefits from the less synchronized, multiple-in-flight-data > global queue will still outweigh the costs of dynamic allocations. But > if worst comes to worst then we just go back to a globally synchronous > one-at-a-time implementation, but that would be pretty sad! > What if we went the other way and strictly used queue-per-cpu? It means multicast would require multiple enqueueing operations, which is a bit heavy, but it does make dequeuing and lifetime management very simple... J