Re: CoW memory and Parallax questions.

[Jacob Faber Kloster <jk@cs.aau.dk>]

That certainly sounds like an interesting approach. Our immediate
approach was something along the lines of making a separate service, on
the hypervisor level of privilege, with complete overview and control of
the memory. Doing the content based sharing scheme will, as you also
noted, open up the possibility of overcommitment of memory. Some kind of
scheduling will be needed to handle this. One solution could be to
suspend a VM to disk or introduce a swapping..

But at this point in time we are not focusing on any specific solution,
we are just investigating whether it is possible and feasible to share
memory.

Best regards
Jacob Faber Kloster (group email d515a@cs.aau.dk)


On Tue, 2005-10-04 at 10:53 +0200, Jacob Gorm Hansen wrote:
> My take on that would be to introduce read-only pages and a context
> index (tree or hashtable) in Xen, and then handle the CoW part in the
> guest OSes. That removes the need for any policy on how to handle
> overcommits in Xen or Dom0, in the case where all domUs decide to fill
> up their pages with random data.
> 
> Jacob