From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Vrabel <david.vrabel@citrix.com>
Subject: Re: Linux Xen Balloon Driver Improvement (Draft 2)
Date: Mon, 15 Dec 2014 10:52:40 +0000
Message-ID: <548EBD78.8080904@citrix.com>
References: <20141027123328.GA9067@zion.uk.xensource.com>
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To: Wei Liu <wei.liu2@citrix.com>, xen-devel@lists.xen.org
Cc: Ian Campbell <ian.campbell@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Andrew Cooper <andrew.cooper3@citrix.com>, Dario Faggioli <dario.faggioli@citrix.com>, David Vrabel <david.vrabel@citrix.com>, Boris Ostrovsky <boris.ostrovsky@oracle.com>
List-Id: xen-devel@lists.xenproject.org

On 27/10/14 12:33, Wei Liu wrote:
> 
> ### Periodically exchange normal size pages with huge pages
> 
> Worker thread wakes up periodically to check if there are enough pages
> in normal size page queue to coalesce into a huge page. If so, it will
> try to exchange that huge page into a number of normal size pages with
> XENMEM\_exchange hypercall.

As Andrew recently pointed out[1], changes to a guest's p2m are not
properly handled during migration.  This would have to be fixed before
we can have any sort of background memory exchange process.

David

[1] http://lists.xen.org/archives/html/xen-devel/2014-11/msg01954.html