Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751744AbXAWDSw (ORCPT ); Mon, 22 Jan 2007 22:18:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751934AbXAWDSw (ORCPT ); Mon, 22 Jan 2007 22:18:52 -0500 Received: from ausmtp05.au.ibm.com ([202.81.18.154]:58183 "EHLO ausmtp05.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751744AbXAWDSw (ORCPT ); Mon, 22 Jan 2007 22:18:52 -0500 Message-ID: <45B57E73.3000307@in.ibm.com> Date: Tue, 23 Jan 2007 08:48:11 +0530 From: Balbir Singh Reply-To: balbir@in.ibm.com Organization: IBM User-Agent: Thunderbird 1.5.0.9 (X11/20070103) MIME-Version: 1.0 To: Christoph Lameter CC: Andrea Arcangeli , Niki Hammler , linux-kernel@vger.kernel.org, Vaidyanathan Srinivasan Subject: Re: Why active list and inactive list? References: <45B55286.5060909@nobaq.net> <20070123003939.GY13798@opteron.random> <45B56575.10807@in.ibm.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1639 Lines: 42 Christoph Lameter wrote: > On Tue, 23 Jan 2007, Balbir Singh wrote: > >> This makes me wonder if it makes sense to split up the LRU into page >> cache LRU and mapped pages LRU. I see two benefits >> >> 1. Currently based on swappiness, we might walk an entire list >> searching for page cache pages or mapped pages. With these >> lists separated, it should get easier and faster to implement >> this scheme >> 2. There is another parallel thread on implementing page cache >> limits. If the lists split out, we need not scan the entire >> list to find page cache pages to evict them. >> >> Of course I might be missing something (some piece of history) > > This means page cache = unmapped file backed page right? Otherwise this > would not work. I always thought that the page cache were all file backed > pages both mapped and unmapped. > Yes, unfortunately my terminology was not clear. I mean unmapped file backed pages. > With the proposed schemd you would have to move pages between lists if > they are mapped and unmapped by a process. Terminating a process could > lead to lots of pages moving to the unnmapped list. > When you unmap or map, you need to touch the pte entries and know the pages involved, so shouldn't be equivalent to a list_del and list_add for each page impacted by the map/unmap operation? -- Balbir Singh Linux Technology Center IBM, ISTL - 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/