From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758064AbYG3Le4 (ORCPT ); Wed, 30 Jul 2008 07:34:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752756AbYG3Let (ORCPT ); Wed, 30 Jul 2008 07:34:49 -0400 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:56127 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752753AbYG3Les (ORCPT ); Wed, 30 Jul 2008 07:34:48 -0400 Date: Wed, 30 Jul 2008 04:34:48 -0700 (PDT) Message-Id: <20080730.043448.217891740.davem@davemloft.net> To: peterz@infradead.org Cc: mingo@elte.hu, linux-kernel@vger.kernel.org Subject: Re: [PATCH] lockdep: change scheduler annotation From: David Miller In-Reply-To: <1217417217.8157.23.camel@twins> References: <20080728.174415.154327359.davem@davemloft.net> <20080729.214503.126934382.davem@davemloft.net> <1217417217.8157.23.camel@twins> X-Mailer: Mew version 5.2 on Emacs 22.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra Date: Wed, 30 Jul 2008 13:26:57 +0200 > While thinking about David's patch it _finally_ dawned on me that there > is no reason we have a lock class per cpu.. > > Sorry for being dense :-/ > > The below changes the annotation from a lock class per cpu, to a single > nested lock, as the scheduler never holds more that 2 rq locks at a time > anyway. > > If there was code requiring holding all rq locks this would not work and > the original annotation would be the only option, but that not being the > case, this is a much lighter one. > > Compiles and boots on a 2-way x86_64. > > Signed-off-by: Peter Zijlstra I had been wondering this entire debugging session why the per-rq lock classes were even there, thanks for getting rid of them :)