This patch adds 2 new GFP flags to correspond to the 3 allocation types.  The
third state is indicated by neither flag corresponding to the first two states
being set. It then modifies appropriate allocator calls to use these new flags.
The flags are:
__GFP_USER, which corresponds to easily reclaimable pages
__GFP_KERNRCLM, which corresponds to userspace pages

Also note that the __GFP_USER flag should be reusable by the HARDWALL folks as
well.

This patch was originally authored by Mel Gorman, and heavily modified by me.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Joel Schopp <jschopp@austin.ibm.com>