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Re: [XenPPC] htab allocation

On Mon, 2006-08-14 at 19:17 -0400, Jimi Xenidis wrote:
> On Aug 14, 2006, at 6:50 PM, Hollis Blanchard wrote:
> >
> > I think it might make sense to allocate the HTAB from the domain heap
> > instead, but it's working for now...
> maybe, can't see why not. In fact I'd like to see the domain give up  
> their own non-RMA memory to "make" an htab.  This allows for a very  
> clean max_domains = (memory - 64M)/memory_per_domain.  Makes  
> configuration-management way easier.

That doesn't sound bad, but it would require some work in libxc and the
python bindings to inform Xen of the special properties of certain data
areas (e.g. the hash table). For example, Xen would have to know not to
allow the guest to map it, and not to try to balloon it. If we have the
python tools allocate the RMA we'll need to do something very similar
anyways. We already have our own arch-specific "dom0 op" hypercalls to
work with...

That reminds me, one of my recent changesets removed the domain=64MB
assumption from libxc. I did a quick grep and we may actually be mostly
free from that limitation. I still need to figure out the Right Way to
pass that memory allocation info from Xend to Xen, but it should be
getting pretty easy to have domains with >64MB of memory.

Hollis Blanchard
IBM Linux Technology Center

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