From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932835AbXCUQN7 (ORCPT ); Wed, 21 Mar 2007 12:13:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932873AbXCUQNq (ORCPT ); Wed, 21 Mar 2007 12:13:46 -0400 Received: from mx1.redhat.com ([66.187.233.31]:36605 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932835AbXCUQNh (ORCPT ); Wed, 21 Mar 2007 12:13:37 -0400 Message-ID: <4601598A.7060904@redhat.com> Date: Wed, 21 Mar 2007 12:12:58 -0400 From: Chuck Ebbert Organization: Red Hat User-Agent: Thunderbird 1.5.0.10 (X11/20070302) MIME-Version: 1.0 To: Rik van Riel CC: Nikita Danilov , Linux Kernel Mailing List , linux-mm Subject: Re: [RFC][PATCH] split file and anonymous page queues #3 References: <46005B4A.6050307@redhat.com> <17920.61568.770999.626623@gargle.gargle.HOWL> <460115D9.7030806@redhat.com> <17921.7074.900919.784218@gargle.gargle.HOWL> <46011E8F.2000109@redhat.com> In-Reply-To: <46011E8F.2000109@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Rik van Riel wrote: > Nikita Danilov wrote: > >> Probably I am missing something, but I don't see how that can help. For >> example, suppose (for simplicity) that we have swappiness of 100%, and >> that fraction of referenced anon pages gets slightly less than of file >> pages. get_scan_ratio() increases anon_percent, and shrink_zone() starts >> scanning anon queue more aggressively. As a result, pages spend less >> time there, and have less chance of ever being accessed, reducing >> fraction of referenced anon pages further, and triggering further >> increase in the amount of scanning, etc. Doesn't this introduce positive >> feed-back loop? > > It's a possibility, but I don't think it will be much of an > issue in practice. > > If it is, we can always use refaults as a correcting > mechanism - which would have the added benefit of being > able to do streaming IO without putting any pressure on > the active list, essentially clock-pro replacement with > just some tweaks to shrink_list()... > I think you're going to have to use refault rates. AIX 3.5 had to add that. Something like: if refault_rate(anonymous/mmap) > refault_rate(pagecache) drop a pagecache page else drop either You do have anonymous memory and mmapped executables in the same queue, right?