From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759085AbZBYENT (ORCPT ); Tue, 24 Feb 2009 23:13:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753854AbZBYENE (ORCPT ); Tue, 24 Feb 2009 23:13:04 -0500 Received: from mx2.suse.de ([195.135.220.15]:47622 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753821AbZBYEND (ORCPT ); Tue, 24 Feb 2009 23:13:03 -0500 Date: Wed, 25 Feb 2009 05:12:59 +0100 From: Nick Piggin To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, vegard.nossum@gmail.com, mingo@elte.hu, stable@kernel.org, akpm@linux-foundation.org, penberg@cs.helsinki.fi Subject: Re: [PATCH] v3 Teach RCU that idle task is not quiscent state at boot Message-ID: <20090225041259.GA14149@wotan.suse.de> References: <20090223161611.GA9563@linux.vnet.ibm.com> <20090223204332.GA19861@linux.vnet.ibm.com> <20090225002937.GA23733@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090225002937.GA23733@linux.vnet.ibm.com> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Looks OK to me. It's a bit "theoretically" displeasing that you still treat synchronize_rcu as a gp even after we spawn some kernel threads. ... but it probably isn't worth trying to rearrange the boot code just to make this look better. I can't see any actual problems that could arise, as the threads should not have had a chance to run yet. I wonder if you couldn't put in a WARN_ON(nr_context_switches() > 0) in rcu_idle_now_means_idle() just in case? On Tue, Feb 24, 2009 at 04:29:37PM -0800, Paul E. McKenney wrote: > This patch fixes a bug located by Vegard Nossum with the aid of > kmemcheck, updated based on review comments from Nick Piggin, > Ingo Molnar, and Andrew Morton.