From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id 8A7CD6B004D for ; Fri, 16 Oct 2009 12:56:54 -0400 (EDT) Received: from localhost (smtp.ultrahosting.com [127.0.0.1]) by smtp.ultrahosting.com (Postfix) with ESMTP id 7A4C982C2BE for ; Fri, 16 Oct 2009 13:01:34 -0400 (EDT) Received: from smtp.ultrahosting.com ([74.213.174.253]) by localhost (smtp.ultrahosting.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Ta8k8PfxrI9V for ; Fri, 16 Oct 2009 13:01:29 -0400 (EDT) Received: from gentwo.org (unknown [74.213.171.31]) by smtp.ultrahosting.com (Postfix) with ESMTP id B2FFA82C6D5 for ; Fri, 16 Oct 2009 13:01:25 -0400 (EDT) Date: Fri, 16 Oct 2009 12:48:34 -0400 (EDT) From: Christoph Lameter Subject: Re: [PATCH 2/2][v2] powerpc: Make the CMM memory hotplug aware In-Reply-To: <4AD7681C.7060800@linux.vnet.ibm.com> Message-ID: References: <20091002184458.GC4908@austin.ibm.com> <20091002185248.GD4908@austin.ibm.com> <4ACDD71D.30809@linux.vnet.ibm.com> <20091008131355.GA22118@austin.ibm.com> <4AD7681C.7060800@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: gerald.schaefer@de.ibm.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@ozlabs.org, Robert Jennings , Mel Gorman , Ingo Molnar , Badari Pulavarty , Brian King , Benjamin Herrenschmidt , Paul Mackerras , Martin Schwidefsky , KAMEZAWA Hiroyuki , Nick Piggin List-ID: On Thu, 15 Oct 2009, Gerald Schaefer wrote: > > The pages allocated as __GFP_MOVABLE are used to store the list of pages > > allocated by the balloon. They reference virtual addresses and it would > > be fine for the kernel to migrate the physical pages for those, the > > balloon would not notice this. > > Does page migration really work for kernel pages that were allocated > with __get_free_page()? I was wondering if we can do this on s390, where > we have a 1:1 mapping of kernel virtual to physical addresses, but > looking at migrate_pages() and friends, it seems that kernel pages > w/o mapping and rmap should not be migrateable at all. Any thoughts from > the memory migration experts? page migration only works for pages where we have some way of accounting for all the references to a page. This usually mean using reverse mappings (anon list, radix trees and page tables). -- 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