From mboxrd@z Thu Jan 1 00:00:00 1970 From: Apoorva Kulkarni Subject: Re: HVM and free_memory query Date: Fri, 10 Jul 2009 11:33:56 -0700 Message-ID: <4A578994.3040806@3tera.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org 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 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.