There are a couple of places where we seem to go round the houses to get
the numa node id from a page.  We have a macro for this so it seems
sensible to use that.

Both lookup_node and enqueue_huge_page use page_zone() to locate the zone,
that to locate node pgdat_t and that to get the node_id.  Its more
efficient to use page_to_nid() which gets the nid from the page flags,
especially if we are not using the zone for anything else it.  Change these
to use page_to_nid().
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>