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Re: [Xen-devel] memory size inside domU less than memory in domU config

To: Vasiliy G Tolstov <v.tolstov@xxxxxxxxx>
Subject: Re: [Xen-devel] memory size inside domU less than memory in domU config
From: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Date: Thu, 16 Jun 2011 15:25:15 -0400
Cc: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
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On Thu, Jun 16, 2011 at 11:18:58PM +0400, Vasiliy G Tolstov wrote:
> On Thu, 2011-06-16 at 12:12 -0700, Dan Magenheimer wrote:
> > I'm not sure, but I think Vasiliy's question is:
> > 
> > Why/where is 78MB of memory being "wasted"?  If one specifies
> > 2048MB (4096MB) of memory for the guest, why doesn't the guest
> > kernel report 2048MB (4096MB)?
> > 
> > Using Vasiliy's /proc/meminfo output from below:
> > 2048MB = 2097152KB; - 2016564KB = 80588KB = 78MB
> > 4096MB = 4194304KB; - 4113716KB = 80588KB = 78MB
> > 
> > Dan
> > 
> > Thanks... for the memory!
> > I really could use more / my throughput's on the floor
> > The balloon is flat / my swap disk's fat / I've OOM's in store
> > Overcommitted so much
> > (with apologies to Bob Hope)
> =) Thanks Dan. May be this happening because i check dom0 support. I'm
> try to rebuild kernel to use Daniel's memory hotplug and disable dom0
> support.

Ah, that is what you meant. You are probably hitting a bug introduced
by 24bdb0b62cc82120924762ae6bc85afc8c3f2b26. Can you try the attached patch 

It might not apply cleanly - if so you will have to manually fix it up.

Or you can merge stable/bug.fixes from


and that will take care of that.

Attachment: xen_extra_mem_start.patch
Description: Text Data

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