From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by wproxy.gmail.com with SMTP id 36so1394361wra for ; Sun, 12 Mar 2006 18:28:45 -0800 (PST) Message-ID: Date: Mon, 13 Mar 2006 11:28:45 +0900 From: "Magnus Damm" Subject: Re: [PATCH 00/03] Unmapped: Separate unmapped and mapped pages In-Reply-To: <1142110694.2928.6.camel@lappy> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Content-Disposition: inline References: <20060310034412.8340.90939.sendpatchset@cherry.local> <1141977139.2876.15.camel@laptopd505.fenrus.org> <1142110694.2928.6.camel@lappy> Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: Arjan van de Ven , Magnus Damm , Linux Kernel , linux-mm@kvack.org List-ID: 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, 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