From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266309AbUBDHSG (ORCPT ); Wed, 4 Feb 2004 02:18:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266311AbUBDHSG (ORCPT ); Wed, 4 Feb 2004 02:18:06 -0500 Received: from citrine.spiritone.com ([216.99.193.133]:26826 "EHLO citrine.spiritone.com") by vger.kernel.org with ESMTP id S266309AbUBDHSE (ORCPT ); Wed, 4 Feb 2004 02:18:04 -0500 Date: Tue, 03 Feb 2004 23:17:57 -0800 From: "Martin J. Bligh" To: Dave Hansen cc: Alok Mooley , Linux Kernel Mailing List , linux-mm Subject: Re: Active Memory Defragmentation: Our implementation & problems Message-ID: <1180000.1075879076@[10.10.2.4]> In-Reply-To: <1075876826.14166.314.camel@nighthawk> References: <20040204050915.59866.qmail@web9704.mail.yahoo.com> <1075874074.14153.159.camel@nighthawk> <35380000.1075874735@[10.10.2.4]> <1075875756.14153.251.camel@nighthawk> <38540000.1075876171@[10.10.2.4]> <1075876826.14166.314.camel@nighthawk> X-Mailer: Mulberry/2.2.1 (Linux/x86) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org >> There are a couple of special cases that might be feasible without making >> an ungodly mess. PTE pages spring to mind (particularly as they can be >> in highmem too). They should be reasonably easy to move (assuming we can >> use rmap to track them back to the process they belong to to lock them ... >> hmmm ....) > > We don't do any pte page reclaim at any time other than process exit and > there are plenty of pte pages we can just plain free anyway. Anthing > that's completely mapping page cache, for instance. > > In the replacement case, taking mm->page_table_lock, doing the copy, and > replacing the pointer from the pmd should be all that it takes. But, I > wonder if we could miss any sets of the pte dirty bit this way... As long as we make sure the process doesn't run during the move, I don't see why it'd be a problem. But I am less than convinced that rmap will lead us back from the PTE page to the mm, at least w/o modification. M.