From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35358) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1chDAN-0001hi-Pg for qemu-devel@nongnu.org; Fri, 24 Feb 2017 05:32:00 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1chDAK-0002Cl-Ma for qemu-devel@nongnu.org; Fri, 24 Feb 2017 05:31:59 -0500 Received: from mx1.redhat.com ([209.132.183.28]:49474) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1chDAK-0002C1-GY for qemu-devel@nongnu.org; Fri, 24 Feb 2017 05:31:56 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9F5E580484 for ; Fri, 24 Feb 2017 10:31:56 +0000 (UTC) References: <20170206173306.20603-1-dgilbert@redhat.com> <20170206173306.20603-3-dgilbert@redhat.com> From: Laurent Vivier Message-ID: <2d0b399e-3ebe-620c-f845-5f61fc55e170@redhat.com> Date: Fri, 24 Feb 2017 11:31:48 +0100 MIME-Version: 1.0 In-Reply-To: <20170206173306.20603-3-dgilbert@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 02/16] postcopy: Transmit and compare individual page sizes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert (git)" , qemu-devel@nongnu.org, quintela@redhat.com Cc: aarcange@redhat.com On 06/02/2017 18:32, Dr. David Alan Gilbert (git) wrote: > From: "Dr. David Alan Gilbert" > > When using postcopy with hugepages, we require the source > and destination page sizes for any RAMBlock to match; note > that different RAMBlocks in the same VM can have different > page sizes. > > Transmit them as part of the RAM information header and > fail if there's a difference. > > Signed-off-by: Dr. David Alan Gilbert > --- > migration/ram.c | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/migration/ram.c b/migration/ram.c > index b405e4a..5726563 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -1979,6 +1979,9 @@ static int ram_save_setup(QEMUFile *f, void *opaque) > qemu_put_byte(f, strlen(block->idstr)); > qemu_put_buffer(f, (uint8_t *)block->idstr, strlen(block->idstr)); > qemu_put_be64(f, block->used_length); > + if (migrate_postcopy_ram() && block->page_size != qemu_host_page_size) { > + qemu_put_be64(f, block->page_size); > + } I understand we don't break migration to previous machine type by adding data in the migration stream because migration is already broken when block->page_size != qemu_host_page_size. Am I correct? Laurent