From: David Rientjes <rientjes@google.com>
Date: Fri, 20 May 2016 23:59:05 +0000 (-0700)
Subject: mm, migrate: increment fail count on ENOMEM
X-Git-Tag: v4.9.8~2047^2~107
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=dfef2ef4027b1304149a65dc33794eab65e8a3bf;p=platform%2Fkernel%2Flinux-rpi3.git

mm, migrate: increment fail count on ENOMEM

If page migration fails due to -ENOMEM, nr_failed should still be
incremented for proper statistics.

This was encountered recently when all page migration vmstats showed 0,
and inferred that migrate_pages() was never called, although in reality
the first page migration failed because compaction_alloc() failed to
find a migration target.

This patch increments nr_failed so the vmstat is properly accounted on
ENOMEM.

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1605191510230.32658@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/migrate.c b/mm/migrate.c
index 53ab639..9baf41c 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1171,6 +1171,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
 
 			switch(rc) {
 			case -ENOMEM:
+				nr_failed++;
 				goto out;
 			case -EAGAIN:
 				retry++;