RE: [Xen-devel] One question on alloc_bitmap

Jiang, Yunhong
Fri, 19 Sep 2008 09:17:13 -0000

Keir Fraser <mailto:keir.fraser@eu.citrix.com>
wrote:
> 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.

Thanks for your clarification. We ask this because we are considering memory
online.

Yunhong Jiang

>
> -- Keir