Re: Balloon driver.

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Wed, Jul 07, 2010 at 01:57:30PM +0530, Cherry G. Mathew wrote:
> >
> > How would you stop the domU being able to increase its memory size (e.g. on
> > a hosted service, you wouldn't want the client taking more resources than
> > they've paid for)?
> >
> 
> There are no such limits by design at the moment. However at the
> moment a de-facto limit exists (ie; the amount specified in the domU
> config file), because we don't add more pages than we had to begin
> with. Fixing this will need looking at uvm(9).)

This is pretty bogus -- it seems like it allows a single domU to
effectively take over the entire virtualization environment.  I think
there really needs to be a hard cap enforced by the dom0 -- what's to
keep a misbehaving Linux domU, for instance, which starts up early, from
balooning away every last page on the machine and preventing later domUs
from starting?

I believe this should be disabled on the dom0 side by default until
this problem is addressed.

Thor