mm, tracing: make show_gfp_flags() up to date

mm, tracing: make show_gfp_flags() up to date

The show_gfp_flags() macro provides human-friendly printing of gfp flags
in tracepoints.  However, it is somewhat out of date and missing several
flags.  This patches fills in the missing flags, and distinguishes
properly between GFP_ATOMIC and __GFP_ATOMIC which were both translated
to "GFP_ATOMIC".  More generally, all __GFP_X flags which were
previously printed as GFP_X, are now printed as __GFP_X, since ommiting
the underscores results in output that doesn't actually match the source
code, and can only lead to confusion.  Where both variants are defined
equal (e.g.  _DMA and _DMA32), the variant without underscores are
preferred.

Also add a note in gfp.h so hopefully future changes will be synced
better.

__GFP_MOVABLE is defined twice in include/linux/gfp.h with different
comments.  Leave just the newer one, which was intended to replace the
old one.

Signed-off-by: Vlastimil Babka <[email protected]>
Reviewed-by: Michal Hocko <[email protected]>
Acked-by: David Rientjes <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Sasha Levin <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>