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Re: [Xen-devel] Re: GSoC 2010 - Migration from memory ballooning to memo

To: Andi Kleen <andi@xxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] Re: GSoC 2010 - Migration from memory ballooning to memory hotplug in Xen
From: Daniel Kiper <dkiper@xxxxxxxxxxxx>
Date: Fri, 9 Jul 2010 19:32:56 +0200
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, Daniel Kiper <dkiper@xxxxxxxxxxxx>
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On Fri, Jul 09, 2010 at 02:34:09AM +0200, Andi Kleen wrote:
> > > The only advantage of using memory hotadd is that the mem_map doesn't
> > > need to be pre-allocated, but that's only a few percent of the memory.
> > >
> > > So it would only help if you want to add gigantic amounts of memory
> > > to a VM (like >20-30x of what it already has).
> >
> > That's not wildly unreasonable on the face of it; consider a domain
> > which starts at 1GB but could go up to 32GB as demand requires.  But
> The programs which need 32GB will probably not even start in 1GB :)

I am able to run program which allocates 32GB on machine 1GB... :-)))
Do not underestimate memory overcommit...


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