From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 24 Sep 2001 14:29:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 24 Sep 2001 14:29:29 -0400 Received: from humbolt.nl.linux.org ([131.211.28.48]:19217 "EHLO humbolt.nl.linux.org") by vger.kernel.org with ESMTP id ; Mon, 24 Sep 2001 14:29:22 -0400 Content-Type: text/plain; charset=US-ASCII From: Daniel Phillips To: VDA , Andrea Arcangeli , Rik van Riel , Alexander Viro Subject: Re: Linux VM design Date: Mon, 24 Sep 2001 20:37:17 +0200 X-Mailer: KMail [version 1.3.1] Cc: linux-kernel@vger.kernel.org In-Reply-To: <20010916204528.6fd48f5b.skraw@ithnet.com> <20010922105332Z16449-2757+1233@humbolt.nl.linux.org> <6514162334.20010924123631@port.imtp.ilyichevsk.odessa.ua> In-Reply-To: <6514162334.20010924123631@port.imtp.ilyichevsk.odessa.ua> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Message-Id: <20010924182948Z16175-2757+1593@humbolt.nl.linux.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On September 24, 2001 11:36 am, VDA wrote: > Daniel Phillips wrote: > DP> The arguments in support of aging over LRU that I'm aware of are: > > DP> - incrementing an age is more efficient than resetting several LRU > DP> list links > DP> - also captures some frequency-of-use information > > Of what use this info can be? If one page is accessed 100 times/second > and other one once in 10 seconds, they both have to stay in RAM. > VM should take 'time since last access' into account whan deciding > which page to swap out, not how often it was referenced. You might want to have a look at this: http://archi.snu.ac.kr/jhkim/seminar/96-004.ps (lrfu algorithm) To tell the truth, I don't really see why the frequency information is all that useful either. Rik suggested it's good for streaming IO but we already have effective means of dealing with that that don't rely on any frequency information. So the list of reasons why aging is good is looking really short. -- Daniel