Teach kswapd to free memory on behalf of higher order allocators.  This
could be important for higher order atomic allocations because they
otherwise have no means to free the memory themselves.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>