[PATCH 4.9 038/310] mm, vmstat: Remove spurious WARN() during zoneinfo print

[Greg Kroah-Hartman]

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

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

From: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx>


[ Upstream commit 8d35bb310698c69d73073b26fc581f2e3f7f621d ]

After commit e2ecc8a79ed4 ("mm, vmstat: print non-populated zones in
zoneinfo"), /proc/zoneinfo will show unpopulated zones.

A memoryless node, having no populated zones at all, was previously
ignored, but will now trigger the WARN() in is_zone_first_populated().

Remove this warning, as its only purpose was to warn of a situation that
has since been enabled.

Aside: The "per-node stats" are still printed under the first populated
zone, but that's not necessarily the first stanza any more.  I'm not
sure which criteria is more important with regard to not breaking
parsers, but it looks a little weird to the eye.

Fixes:  e2ecc8a79ed4 ("mm, vmstat: print node-based stats in zoneinfo file")
Link: http://lkml.kernel.org/r/1493854905-10918-1-git-send-email-arbab@xxxxxxxxxxxxxxxxxx
Signed-off-by: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 mm/vmstat.c |    2 --
 1 file changed, 2 deletions(-)

--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1351,8 +1351,6 @@ static bool is_zone_first_populated(pg_d
 			return zone == compare;
 	}
 
-	/* The zone must be somewhere! */
-	WARN_ON_ONCE(1);
 	return false;
 }