From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753097AbZCHQAd (ORCPT ); Sun, 8 Mar 2009 12:00:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752636AbZCHQAY (ORCPT ); Sun, 8 Mar 2009 12:00:24 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:57153 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752479AbZCHQAX (ORCPT ); Sun, 8 Mar 2009 12:00:23 -0400 Date: Sun, 8 Mar 2009 17:00:05 +0100 From: Ingo Molnar To: Lai Jiangshan Cc: "Paul E. McKenney" , Peter Zijlstra , LKML Subject: Re: [PATCH] rcu_barrier VS cpu_hotplug: Ensure callbacks in dead cpu are migrated to online cpu Message-ID: <20090308160005.GE19658@elte.hu> References: <49B2526E.40106@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49B2526E.40106@cn.fujitsu.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Lai Jiangshan wrote: > [RFC] > I don't like this patch, but I thought for some days and I can't > thought out a better one. Interesting find. Found via code review or via testing? If via testing, what is the symptom of the bug when it hits - did you see CPU hotplug stress-tests hanging? Crashing too perhaps? How frequently did it occur? It also appears we introduced this bug at around 2.6.26 (when the CPU hotplug code was rewritten) - or had it before that as well. We are late in -rc's so i'm trying to scope whether it's a 2.6.29 must-have or can wait for 2.6.30. Ingo