From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755911AbYKKJ5P (ORCPT ); Tue, 11 Nov 2008 04:57:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755172AbYKKJ47 (ORCPT ); Tue, 11 Nov 2008 04:56:59 -0500 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:48565 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754749AbYKKJ46 (ORCPT ); Tue, 11 Nov 2008 04:56:58 -0500 From: KOSAKI Motohiro To: Peter Zijlstra Subject: Re: How kernel applies LRU to swap out physical pages? Cc: kosaki.motohiro@jp.fujitsu.com, Pan ruochen , linux-kernel@vger.kernel.org In-Reply-To: <1226393845.7685.1294.camel@twins> References: <1226393845.7685.1294.camel@twins> Message-Id: <20081111180233.8B38.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.42 [ja] Date: Tue, 11 Nov 2008 18:56:55 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Tue, 2008-11-11 at 16:22 +0800, Pan ruochen wrote: > > Hi All, > > I'm reading the linux kernel 2.6.14. But can't understand how LRU algorithm > > is applied to page swapping. what is the 'USED' of LRU referred to? The > > reference counter which the page is mapped by processes, or the frequency that > > CPU reads/writes in the page. In common sense, the LRU algorithm will be more > > optimal for the second case. But it depends on CPU capability. > > I will be very appreciated if somebody can explain that in details. > > We don't actually use LRU but something like CLOCK. Yup. However, VM replace algorithm folks commonly call it to "LRU" because MACH call so. IOW, it is historical reason word, shouldn't imazine strict "Least Recently Used" algorithm.