From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vasiliy G Tolstov Subject: Re: memory size inside domU less than memory in domU config Date: Mon, 20 Jun 2011 18:55:04 +0400 Message-ID: <1308581704.13237.9.camel@vase> References: <1308248350.28653.5.camel@mobile> <4DFB3FD50200007800047F63@nat28.tlf.novell.com> <1308304996.524.0.camel@vase> <20110620143611.GA15251@dumpdata.com> Reply-To: v.tolstov@selfip.ru Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110620143611.GA15251@dumpdata.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Konrad Rzeszutek Wilk Cc: xen-devel@lists.xensource.com, Jan Beulich List-Id: xen-devel@lists.xenproject.org On Mon, 2011-06-20 at 10:36 -0400, Konrad Rzeszutek Wilk wrote: > So I tried the same experiment - a physical machine with 'mem=1G' provided > and an PV guest with 'mem=1G'. The same exact kernel in both cases and got: > > Machine with 'mem=1G' on the command line. > [ 0.000000] Memory: 1022756k/1048576k available (5851k kernel code, 452k absent, 25368k reserved, 2881k data, 688k init) > > PV guest: > [ 0.000000] Memory: 1018888k/1048576k available (5851k kernel code, 448k absent, 29240k reserved, 2881k data, 688k init) > > So a DomU guest "eats" an extra 4MB compared to running it under baremetal. > (Note, the DomU guest has no balloon space in this example). > > The memblock=debug does provide the info of what the "other" reserved regions are > and it looks to be the matter of just going through the numbers to figure out what > it is. > Can You provide pv kernel cmdline and config file ? -- Vasiliy G Tolstov Selfip.Ru