From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <435866E0.8080305@jp.fujitsu.com> Date: Fri, 21 Oct 2005 12:56:16 +0900 From: KAMEZAWA Hiroyuki MIME-Version: 1.0 Subject: Re: [PATCH 0/4] Swap migration V3: Overview 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> <20051021033223.GC6846@w-mikek2.ibm.com> In-Reply-To: <20051021033223.GC6846@w-mikek2.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: mike kravetz Cc: Andrew Morton , Christoph Lameter , linux-kernel@vger.kernel.org, linux-mm@kvack.org, magnus.damm@gmail.com, marcelo.tosatti@cyclades.com List-ID: mike kravetz 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. > yea, looks nice :) But such pages are already shown as hotpluggable, I think. ACPI/SRAT will define the range, in ia64. The difficulty is how to find hard-to-migrate pages, as Andrew pointed out. Thanks, -- Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org