Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750883AbWCMC2r (ORCPT ); Sun, 12 Mar 2006 21:28:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751119AbWCMC2q (ORCPT ); Sun, 12 Mar 2006 21:28:46 -0500 Received: from wproxy.gmail.com ([64.233.184.198]:61454 "EHLO wproxy.gmail.com") by vger.kernel.org with ESMTP id S1750883AbWCMC2q convert rfc822-to-8bit (ORCPT ); Sun, 12 Mar 2006 21:28:46 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=Vl1RbzO+Fkvot0wbygmSK/VU2rYyMeTMdYRXLuDspz7/7nb1mFLGaKU8Y4Dl1hJd3/61u5J5WZ33uknqEjGfsQqguPjH07boZ1yg72ni23aRKlpsca9osA6ZMjnEXV2sL7ee6mmq+1+o36a38wtXDqD46eWJVxd0iKyMFhWFNS8= Message-ID: Date: Mon, 13 Mar 2006 11:28:45 +0900 From: "Magnus Damm" To: "Peter Zijlstra" Subject: Re: [PATCH 00/03] Unmapped: Separate unmapped and mapped pages Cc: "Arjan van de Ven" , "Magnus Damm" , "Linux Kernel" , linux-mm@kvack.org In-Reply-To: <1142110694.2928.6.camel@lappy> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Content-Disposition: inline References: <20060310034412.8340.90939.sendpatchset@cherry.local> <1141977139.2876.15.camel@laptopd505.fenrus.org> <1142110694.2928.6.camel@lappy> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1497 Lines: 35 On 3/12/06, Peter Zijlstra wrote: > On Fri, 2006-03-10 at 14:19 +0100, Magnus Damm wrote: > > On 3/10/06, Arjan van de Ven wrote: > > > > Apply on top of 2.6.16-rc5. > > > > > > > > Comments? > > > > > > > > > my big worry with a split LRU is: how do you keep fairness and balance > > > between those LRUs? This is one of the things that made the 2.4 VM suck > > > really badly, so I really wouldn't want this bad... > > > > Yeah, I agree this is important. I think linux-2.4 tried to keep the > > LRU list lengths in a certain way (maybe 2/3 of all pages active, 1/3 > > inactive). In 2.6 there is no such thing, instead the number of pages > > scanned is related to the current scanning priority. > > This sounds wrong, the active and inactive lists are balanced to a 1:1 > ratio. This is happens because the scan speed is directly proportional > to the size of the list. Hence the largest list will shrink fastest - > this gives a natural balance to equal sizes. Yes, you are explaining the current 2.6 behaviour much better. Also, some balancing logic with nr_scan_active/nr_scan_inactive is present in the code today. I'm not entirely sure about the purpose of that code. Thanks, / magnus - 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/