From mboxrd@z Thu Jan  1 00:00:00 1970
From: Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH v7 2/4] virtio_balloon: introduce migration primitives
	to balloon pages
Date: Wed, 15 Aug 2012 11:30:34 -0400
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-mm@kvack.org, Andi Kleen <andi@firstfloor.org>, Minchan Kim <minchan@kernel.org>, Andrew Morton <akpm@linux-foundation.org>
List-Id: virtualization@lists.linuxfoundation.org

On 08/14/2012 05:38 PM, Michael S. Tsirkin wrote:

> And even ignoring that, global pointer to a device
> is an ugly hack and ugly hacks tend to explode.
>
> And even ignoring estetics, and if we decide we are fine
> with a single balloon, it needs to fail gracefully not
> crash like it does now.

Fair enough.  That certainly seems easy enough to fix.

Each balloon driver can have its own struct address_space,
and simply point mapping->host (or any of the others) at
a global balloon thing somewhere.

if (page->mapping && page->mapping->host == balloon_magic)