From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750720AbVKGOl4 (ORCPT ); Mon, 7 Nov 2005 09:41:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750718AbVKGOl4 (ORCPT ); Mon, 7 Nov 2005 09:41:56 -0500 Received: from omx3-ext.sgi.com ([192.48.171.20]:7070 "EHLO omx3.sgi.com") by vger.kernel.org with ESMTP id S1750726AbVKGOlz (ORCPT ); Mon, 7 Nov 2005 09:41:55 -0500 Date: Mon, 7 Nov 2005 06:41:41 -0800 From: Paul Jackson To: Nick Piggin Cc: ak@suse.de, akpm@osdl.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH]: Clean up of __alloc_pages Message-Id: <20051107064141.7be80c49.pj@sgi.com> In-Reply-To: <436F29BF.3010804@yahoo.com.au> References: <20051028183326.A28611@unix-os.sc.intel.com> <20051106124944.0b2ccca1.pj@sgi.com> <436EC2AF.4020202@yahoo.com.au> <200511070442.58876.ak@suse.de> <20051106203717.58c3eed0.pj@sgi.com> <436EEF43.2050403@yahoo.com.au> <20051107014659.14c2631b.pj@sgi.com> <436F29BF.3010804@yahoo.com.au> Organization: SGI X-Mailer: Sylpheed version 2.0.0beta5 (GTK+ 2.4.9; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ok ... so a spinlock (task_lock) costs one barrier and one atomic more than an rcu_read_lock (on a preempt kernel where both spinlock and rcu_read_lock cost a preempt), or something like that. Thanks, Nick. -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.925.600.0401