Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751257AbZLRFSO (ORCPT ); Fri, 18 Dec 2009 00:18:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751200AbZLRFSN (ORCPT ); Fri, 18 Dec 2009 00:18:13 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:58115 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751060AbZLRFSL (ORCPT ); Fri, 18 Dec 2009 00:18:11 -0500 Date: Fri, 18 Dec 2009 06:17:54 +0100 From: Ingo Molnar To: Christoph Lameter Cc: Peter Zijlstra , Andi Kleen , "Paul E. McKenney" , KAMEZAWA Hiroyuki , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "akpm@linux-foundation.org" , minchan.kim@gmail.com Subject: Re: [mm][RFC][PATCH 0/11] mm accessor updates. Message-ID: <20091218051754.GC417@elte.hu> References: <20091217084046.GA9804@basil.fritz.box> <1261039534.27920.67.camel@laptop> <20091217085430.GG9804@basil.fritz.box> <20091217144551.GA6819@linux.vnet.ibm.com> <20091217175338.GL9804@basil.fritz.box> <20091217190804.GB6788@linux.vnet.ibm.com> <20091217195530.GM9804@basil.fritz.box> <1261080855.27920.807.camel@laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -2.0 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 Content-Length: 1029 Lines: 26 * Christoph Lameter wrote: > On Thu, 17 Dec 2009, Peter Zijlstra wrote: > > > > That is why I think that the accessors are a good first step. > > > > They're not, they're daft, they operate on a global resource mm_struct, > > that's the whole problem, giving it a different name isn't going to solve > > anything. > > It is not about naming. The accessors hide the locking mechanism for > mmap_sem. Then you can change the locking in a central place. > > The locking may even become configurable later. Maybe an embedded solution > will want the existing scheme but dual quad socket may want a distributed > reference counter to avoid bouncing cachelines on faults. Hiding the locking is pretty much the worst design decision one can make. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/