From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id A25306B007B for ; Fri, 18 Dec 2009 12:01:14 -0500 (EST) Message-ID: <4B2BB52A.7050103@redhat.com> Date: Fri, 18 Dec 2009 19:00:26 +0200 From: Avi Kivity MIME-Version: 1.0 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: owner-linux-mm@kvack.org 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 List-ID: 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org