From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 16 Sep 2001 15:44:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 16 Sep 2001 15:44:03 -0400 Received: from neon-gw-l3.transmeta.com ([63.209.4.196]:48133 "EHLO neon-gw.transmeta.com") by vger.kernel.org with ESMTP id ; Sun, 16 Sep 2001 15:43:55 -0400 To: linux-kernel@vger.kernel.org From: torvalds@transmeta.com (Linus Torvalds) Subject: Re: broken VM in 2.4.10-pre9 Date: Sun, 16 Sep 2001 19:43:25 +0000 (UTC) Organization: Transmeta Corporation Message-ID: <9o2vct$889$1@penguin.transmeta.com> In-Reply-To: <1000653836.2440.0.camel@gromit.house> X-Trace: palladium.transmeta.com 1000669453 4793 127.0.0.1 (16 Sep 2001 19:44:13 GMT) X-Complaints-To: news@transmeta.com NNTP-Posting-Date: 16 Sep 2001 19:44:13 GMT Cache-Post-Path: palladium.transmeta.com!unknown@penguin.transmeta.com X-Cache: nntpcache 2.4.0b5 (see http://www.nntpcache.org/) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org In article , Rik van Riel wrote: >On 16 Sep 2001, Michael Rothwell wrote: > >> Is there a way to tell the VM to prune its cache? Or a way to limit >> the amount of cache it uses? > >Not yet, I'll make a quick hack for this when I get back next >week. It's pretty obvious now that the 2.4 kernel cannot get >enough information to select the right pages to evict from >memory. Don't be stupid. The desribed behaviour has nothing to do with limiting the cache or anything else "cannot get enough information", except for the fact that the kernel obviously cannot know what will happen in the future. The kernel _correctly_ swapped out tons of pages that weren't touched in a long long time. That's what you want to happen - the fact that they then all became active on logout is sad. The fact that the "use-once" logic didn't kick in is the problem. It's hard to tell _why_ it didn't kick in, possibly because the MP3 player read small chunks of the pages (touching them multiple times). THAT is worth looking into. But blathering about "reverse mappings will help this" is just incredibly stupid. You seem to think that they are a panacea for all problems, ranging from MP3 playback to world peace and re-building the WTC. Linus