Re: [Xen-devel] One question on alloc_bitmap

Keir Fraser
Thu, 18 Sep 2008 15:20:52 -0000

On 18/9/08 16:16, "Jiang, Yunhong" <yunhong.jiang@intel.com>
wrote:

> I have a question to the alloc_bitmap. Currently it is allocated in
> init_page_allocator() and is continous physical memory mapped in direct map
> (1:1 map) range. Would it be possible to support un-continous like
what''s done
> for frame table?
> Several reason I can think out that can be improved is: a) if memory
sparsed
> arranged, like large hole in the memory, it may cost some memory b) if we
want
> to support memory hot add, we can''t increase this bitmap. c) this
map is not
> NUMA aware, I''m not sure if it has any performance impact,
although it is not
> accessed frequently.
>
> Any idea on it?

Yes, it could be sparsely allocated in future. No reason why not.

 -- Keir