Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753838AbZLRRBB (ORCPT ); Fri, 18 Dec 2009 12:01:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753538AbZLRRBA (ORCPT ); Fri, 18 Dec 2009 12:01:00 -0500 Received: from mx1.redhat.com ([209.132.183.28]:30142 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752156AbZLRRA7 (ORCPT ); Fri, 18 Dec 2009 12:00:59 -0500 Message-ID: <4B2BB52A.7050103@redhat.com> Date: Fri, 18 Dec 2009 19:00:26 +0200 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091209 Fedora/3.0-4.fc12 Thunderbird/3.0 MIME-Version: 1.0 To: Ingo Molnar CC: Christoph Lameter , 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. 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> <20091218051754.GC417@elte.hu> In-Reply-To: <20091218051754.GC417@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1071 Lines: 27 On 12/18/2009 07:17 AM, Ingo Molnar wrote: > >> 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. > > It does allow incremental updates. For example if we go with range locks, the accessor turns into a range lock of the entire address space; users can be converted one by one to use their true ranges in order of importance. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain. -- 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/