Use bitmap_weight() instead of doing hweight32() for each u32 element in
the page.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Anton Altaparmakov <aia21@cantab.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>