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Re: [Xen-devel] HVM and free_memory query

To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] HVM and free_memory query
From: Apoorva Kulkarni <apoorva@xxxxxxxxx>
Date: Fri, 10 Jul 2009 11:33:56 -0700
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Keir Fraser wrote:
It's used for shadow pagetables and other memory book-keeping structures.
This reservation is sized as a fraction of the domain's configured memory
allocation -- the fraction is just under 0.8%. And 0.8% of 30720MB is 245MB,
so that works out just about right.

This is one of those cases where a small fraction of a very big number is
still a big number. ;-)

 -- Keir


Thank you for your quick response. That helps a lot.

In our case we need to know precisely how much overhead memory is required by xen per domain. So is it okay for us to assume that it will always be under 0.8% or could there be exceptions to this (e.g. different fractions for a Solaris 10 HVM vs Windows HVM) ?

Thanks again.

Apoorva Kulkarni
3Tera, Inc.

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