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Re: [Xen-devel] Live migration fails under heavy network use

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] Live migration fails under heavy network use
From: John Levon <levon@xxxxxxxxxxxxxxxxx>
Date: Thu, 22 Feb 2007 21:11:21 +0000
Cc: Ian Pratt <m+Ian.Pratt@xxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
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On Thu, Feb 22, 2007 at 08:55:39PM +0000, Keir Fraser wrote:

> Yes, it's because of the extra dom0 mapping. The count is 2 because one
> reference is held at this point by the freeing function in Xen.
> 
> The comment above that warning in the Xen source is a bit strong. I don't
> think we can change the semantics of the existing command but we may add a
> new one to let the caller know whether the page(s) could immediately be
> freed.

Hmm. This debug message has caught one real bug in our balloon code
recently. I presume it's not trivial to distinguish between that case
(where the domain really did have its own mapping) and the
live-migration one though.

regards
john

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