Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964854AbVJUDca (ORCPT ); Thu, 20 Oct 2005 23:32:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964855AbVJUDca (ORCPT ); Thu, 20 Oct 2005 23:32:30 -0400 Received: from e33.co.us.ibm.com ([32.97.110.151]:25307 "EHLO e33.co.us.ibm.com") by vger.kernel.org with ESMTP id S964854AbVJUDca (ORCPT ); Thu, 20 Oct 2005 23:32:30 -0400 Date: Thu, 20 Oct 2005 20:32:23 -0700 From: mike kravetz To: KAMEZAWA Hiroyuki Cc: Andrew Morton , Christoph Lameter , linux-kernel@vger.kernel.org, linux-mm@kvack.org, magnus.damm@gmail.com, marcelo.tosatti@cyclades.com Subject: Re: [PATCH 0/4] Swap migration V3: Overview Message-ID: <20051021033223.GC6846@w-mikek2.ibm.com> References: <20051020225935.19761.57434.sendpatchset@schroedinger.engr.sgi.com> <20051020160638.58b4d08d.akpm@osdl.org> <20051020234621.GL5490@w-mikek2.ibm.com> <43585EDE.3090704@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43585EDE.3090704@jp.fujitsu.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1205 Lines: 27 On Fri, Oct 21, 2005 at 12:22:06PM +0900, KAMEZAWA Hiroyuki wrote: > mike kravetz wrote: > >On Thu, Oct 20, 2005 at 04:06:38PM -0700, Andrew Morton wrote: > > >Just to be clear, there are at least two distinct requirements for hotplug. > >One only wants to remove a quantity of memory (location unimportant). The > >other wants to remove a specific section of memory (location specific). I > >think the first is easier to address. > > > > The only difficulty to remove a quantity of memory is how to find > where is easy to be removed. If this is fixed, I think it is > easier to address. We have been using Mel's fragmentation patches. One of the data structures created by these patches is a 'usemap' thats tracks how 'blocks' of memory are used. I exposed the usemaps via sysfs along with other hotplug memory section attributes. So, you can then have a user space program scan the usemaps looking for sections that can be easily offlined. -- Mike - 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/