From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264305AbUBDTSc (ORCPT ); Wed, 4 Feb 2004 14:18:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264321AbUBDTSc (ORCPT ); Wed, 4 Feb 2004 14:18:32 -0500 Received: from web9704.mail.yahoo.com ([216.136.129.140]:64310 "HELO web9704.mail.yahoo.com") by vger.kernel.org with SMTP id S264305AbUBDTSa (ORCPT ); Wed, 4 Feb 2004 14:18:30 -0500 Message-ID: <20040204191829.57468.qmail@web9704.mail.yahoo.com> Date: Wed, 4 Feb 2004 11:18:29 -0800 (PST) From: Alok Mooley Subject: Re: Active Memory Defragmentation: Our implementation & problems To: root@chaos.analogic.com Cc: linux-kernel , linux-mm , Dave Hansen In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --- "Richard B. Johnson" > If this is an Intel x86 machine, it is impossible > for pages > to get fragmented in the first place. The hardware > allows any > page, from anywhere in memory, to be concatenated > into linear > virtual address space. Even the kernel address space > is virtual. > The only time you need physically-adjacent pages is > if you > are doing DMA that is more than a page-length at a > time. The > kernel keeps a bunch of those pages around for just > that > purpose. > > So, if you are making a "memory defragmenter", it is > a CPU time-sink. > That's all. What if the external fragmentation increases so much that it is not possible to find a large sized block? Then, is it not better to defragment rather than swap or fail? -Alok __________________________________ Do you Yahoo!? Yahoo! SiteBuilder - Free web site building tool. Try it! http://webhosting.yahoo.com/ps/sb/