From: Christoph Lameter <cl@linux-foundation.org>
To: gerald.schaefer@de.ibm.com
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linuxppc-dev@ozlabs.org, Robert Jennings <rcj@linux.vnet.ibm.com>,
Mel Gorman <mel@csn.ul.ie>, Ingo Molnar <mingo@elte.hu>,
Badari Pulavarty <pbadari@us.ibm.com>,
Brian King <brking@linux.vnet.ibm.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Nick Piggin <npiggin@suse.de>
Subject: Re: [PATCH 2/2][v2] powerpc: Make the CMM memory hotplug aware
Date: Fri, 16 Oct 2009 12:48:34 -0400 (EDT) [thread overview]
Message-ID: <alpine.DEB.1.10.0910161246010.6120@gentwo.org> (raw)
In-Reply-To: <4AD7681C.7060800@linux.vnet.ibm.com>
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).
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next prev parent reply other threads:[~2009-10-16 16:56 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-02 18:44 [PATCH 1/2][v2] mm: add notifier in pageblock isolation for balloon drivers Robert Jennings
2009-10-02 18:52 ` [PATCH 2/2][v2] powerpc: Make the CMM memory hotplug aware Robert Jennings
2009-10-08 12:12 ` Gerald Schaefer
2009-10-08 13:13 ` Robert Jennings
2009-10-15 18:21 ` Gerald Schaefer
2009-10-16 16:48 ` Christoph Lameter [this message]
2009-10-08 23:34 ` [PATCH 1/2][v2] mm: add notifier in pageblock isolation for balloon drivers Andrew Morton
2009-10-09 20:23 ` Robert Jennings
2009-10-09 20:43 ` Mel Gorman
2009-10-13 15:48 ` Robert Jennings
2009-10-09 0:47 ` KAMEZAWA Hiroyuki
2009-10-09 14:33 ` Robert Jennings
2009-10-09 11:21 ` Mel Gorman
2009-10-09 14:43 ` Robert Jennings
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