[PATCH 3.11 209/233] mm/mempolicy.c: fix mempolicy printing in numa_maps

[Luis Henriques]

3.11.10.4 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Rientjes <rientjes at google.com>

commit 8790c71a18e5d2d93532ae250bcf5eddbba729cd upstream.

As a result of commit 5606e3877ad8 ("mm: numa: Migrate on reference
policy"), /proc/<pid>/numa_maps prints the mempolicy for any <pid> as
"prefer:N" for the local node, N, of the process reading the file.

This should only be printed when the mempolicy of <pid> is
MPOL_PREFERRED for node N.

If the process is actually only using the default mempolicy for local
node allocation, make sure "default" is printed as expected.

Signed-off-by: David Rientjes <rientjes at google.com>
Reported-by: Robert Lippert <rlippert at google.com>
Cc: Peter Zijlstra <peterz at infradead.org>
Acked-by: Mel Gorman <mgorman at suse.de>
Cc: Ingo Molnar <mingo at kernel.org>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
[ luis: backported to 3.11: used David Rientjes's backport to 3.10 and
  3.12 stable trees. ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 mm/mempolicy.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index bfa95cf..bfb3238 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2806,7 +2806,7 @@ int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
 	 */
 	VM_BUG_ON(maxlen < strlen("interleave") + strlen("relative") + 16);
 
-	if (!pol || pol == &default_policy)
+	if (!pol || pol == &default_policy || (pol->flags & MPOL_F_MORON))
 		mode = MPOL_DEFAULT;
 	else
 		mode = pol->mode;
-- 
1.8.3.2