Re: [hybrid] : mmap pfn space...

[Mukesh Rathor <mukesh.rathor@oracle.com>]

On Mon, 16 Apr 2012 17:22:14 +0100
Stefano Stabellini <stefano.stabellini@eu.citrix.com> wrote:

> On Mon, 16 Apr 2012, Ian Campbell wrote:
> > > In a nutshell, I am still trying to figure how to allocate rsvd
> > > pfn's for privcmd without writing a slab allocator.
> > 
> > Can't you just use the core get_page function (or
> > alloc_xenballooned_pages) and move the associated mfn aside
> > temporarily (or not if using alloc_xenballooned_pages)?
> 
> I think that is a good suggestion: if we are trying to get in
> something that works but might not be the best solution, then using
> alloc_xenballooned_pages to get some pages and then changing the p2m
> is the best option: it wastes a non-trivial amount of memory in dom0
> but at least it is known to work well and it wouldn't be an "hack".
> 
> Give a look at gntdev_alloc_map, gnttab_map_refs and m2p_add_override
> for an example.


Ok. I changed to using alloc_xenballooned_pages. In future, if we run
into problems, we can look into alternatives. In past we've had
problems with limits reached ballooing down. We run with small dom0.

thanks,
Mukesh