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Re: [Xen-devel] What actually destroys a domain?

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>, Jimi Xenidis <jimix@xxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] What actually destroys a domain?
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Wed, 13 Sep 2006 13:15:13 +0100
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On 13/9/06 10:23, "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx> wrote:

>>> Xenconsoled's mapping of the console page should keep the domain
>>> alive.
>> hmm, I'm having trouble associating the "mapping" and a refcount of
>> some sort somewhere, any pointers?
> See share_xen_page_with_guest() in arch/x86/mm.c. The refcnt is dropped when
> xenheap_pages field reduces to zero in
> common/page_alloc.c:free_domheap_pages().

Sorry, I'm talking rubbish here. As you say, the relevant code is actually
in the foreign mapping paths (e.g., in arch/x86/mm.c). Those paths do a
get_page() on the foreign page. This stops it being removed from the domU
page list. A non-empty page list holds a reference on the domU. So the domU
will not die until that foreign mapping is destroyed.

 -- Keir

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