Hey Mulyadi,

On Mon, Jun 20, 2011 at 10:15 PM, Mulyadi Santosa
[off-list ref] wrote:
...snip...

looking at how page_count implemented, it checks whether the related
page is gonna be reclaimed or a compound page (not sure what it is).
If so, returns the first page of that "page".

On the ARM, you can setup the MMU to map 1Mb regions or 4Kb regions. A
1 Mb region only goes through the top level of the MMU, whereas a 4K
page has to go through 2 levesl, so accessing pages through the 1 Mb
mapping is faster.

I believe (I'm not 100% sure) that the 256 x 4K pages that make up the
1Mb region are a compound page.

-- 
Dave Hylands
Shuswap, BC, Canada
http://www.davehylands.com