Re: Design question for PV superpage support

[Jeremy Fitzhardinge <jeremy@goop.org>]

Dan Magenheimer wrote:
> BTW, thinking ahead to ballooning with 2MB pages, are we prepared
> to assume that a relinquished 2MB page can't be fragmented?
> While this may be appealing for systems where nearly all
> guests are using 2MB pages, systems where the 2MB guest is
> an odd duck might suffer substantially by making that
> assumption.
>   

Well, I still think that 4k pages are a ludicrously tiny unit of memory 
for Xen to be dealing with, and it shouldn't bother to get out of bed 
for less than 2M.  If we treat 4k pages as the special case then keeping 
the Xen heap unfragmented at the 2M level should be fairly easy, no?

    J