From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:60084)
	by lists.gnu.org with esmtp (Exim 4.71) (envelope-from <pl@kamp.de>)
	id 1UjwhX-0006YA-0Y
	for qemu-devel@nongnu.org; Tue, 04 Jun 2013 15:15:27 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <pl@kamp.de>) id 1UjwhU-00075S-Gh
	for qemu-devel@nongnu.org; Tue, 04 Jun 2013 15:15:22 -0400
Content-Type: text/plain; charset=iso-8859-1
Mime-Version: 1.0 (Mac OS X Mail 6.3 \(1503\))
From: Peter Lieven <pl@kamp.de>
In-Reply-To: <51AE04ED.9030108@redhat.com>
Date: Tue, 4 Jun 2013 21:15:20 +0200
Content-Transfer-Encoding: quoted-printable
Message-Id: <E1D18498-EF65-470A-BAAF-BCE53866D314@kamp.de>
References: <51A7036A.3050407@ozlabs.ru> <51A7049F.6040207@redhat.com>
	<51A70B3D.90609@ozlabs.ru> <51A71705.6060009@kamp.de>
	<51A74D79.7040204@redhat.com>
	<2765FDFA-8050-4AA3-8621-7E9EA2C89F9C@kamp.de>
	<51A764FC.7080705@redhat.com> <51ADF122.70307@kamp.de>
	<51ADF637.7060804@redhat.com> <51ADFBCE.3080200@kamp.de>
	<51ADFC7A.7030009@redhat.com> <51ADFE4C.6050504@kamp.de>
	<51AE04ED.9030108@redhat.com>
Subject: Re: [Qemu-devel] broken incoming migration
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>, "qemu-ppc@nongnu.org" <qemu-ppc@nongnu.org>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, David Gibson <david@gibson.dropbear.id.au>


Am 04.06.2013 um 17:17 schrieb Paolo Bonzini <pbonzini@redhat.com>:

> Il 04/06/2013 16:48, Peter Lieven ha scritto:
>> Still using 3.2, but strange enough the above example is also not
>> increasing RSS size for me.
>>=20
>> Can you try the following:
>> qemu git master with 1G of memory (hanging in bios with no boot =
device)
>> and migrate it. Before migration RSS Size os somewhat
>> around 16MB. After migration its RSS size is in the order of 1G.
>=20
> That may be a kernel bug.  The kernel did not do the copy-on-write =
trick
> on huge zero pages.  It was fixed last year, maybe 3.2 is not enough.
> Try adding a MADV_HUGEPAGE madvise to the testcase and see if it =
reproduces.

that's it. thanks for the pointer. the huge zero page was introduced in =
3.8.

paolo, alexey: can you please verify the following works for you:
https://github.com/plieven/qemu/tree/fix-migration

thanks
peter


>=20
> Paolo
>=20