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[Xen-devel] Re: [PATCH 3/7] libxenlight resend: 8mb physmap slack for pv

To: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>
Subject: [Xen-devel] Re: [PATCH 3/7] libxenlight resend: 8mb physmap slack for pv domains
From: Vincent Hanquez <vincent.hanquez@xxxxxxxxxxxxx>
Date: Thu, 3 Dec 2009 16:10:13 +0000
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Vincent Hanquez <Vincent.Hanquez@xxxxxxxxxxxxx>, Stefano Stabellini <Stefano.Stabellini@xxxxxxxxxxxxx>
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On Wed, Dec 02, 2009 at 06:00:31PM +0000, Andres Lagar-Cavilla wrote:
> Contemplate 8MB of slack for PV domains, since they
> do ballooning (or flipping network rx) and need
> some extra room in their pfn space.
> Note that this does not allocate any extra memory
> to the domain, it simply extends the physmap with
> some extra room for "bounce bufffering back" pfn's
> that are yielded to dom0.

but the memory is still going off from somewhere isn't it ?
all those random memory constants spread around in xend took us quite some time
to get things right in XCP and XenServer, and also for keeping the library as
dumb as possible, I'ld rather have the toolstack set the field in the structure
(even if it end up beeing 8M all the time) than starting adding those things.


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