Hi,
I guess it''s possible but the effect might be not obvious. When you
shrink
the reservation by one page (4K), you just save one entry.
And currently, ballooning works as a kernel module which, from kernel''s
perspective, just simple allocates / frees pages. It makes the code simple
and easier. Resizing the mapping table complicates it. And you''d better
keep
the table contiguous. It''s nasty.
Just my 2 cents. Correct me if I''m wrong.
Thanks,
Weiming
On Tue, Apr 8, 2008 at 8:39 PM, Michael R. Hines
<mhines@cs.binghamton.edu>
wrote:
> Greetings,
>
> Currently, as I understand PV memory allocation,
> the Guest''s pfn -> mfn physmap will get populated
> on-demand as the guest uses more an more of its
> memory reservation.
>
> Is it possible to also make this go in the reverse direction?
>
> For example: let''s say we have a guest that is mostly idle
> and has a great deal of free memory and we decide to balloon
> down the domain. In addition to decreasing the domain''s
> reservation, is it also possible to remove the physmap entries
> in an on-demand fashion as memory is freed up?
>
> --
> /*
> Michael R. Hines
>
http://www.cs.binghamton.edu/~mhines/<http://www.cs.binghamton.edu/%7Emhines/>
> Live long and prosper...
> */
>
>
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