mm, migrate: increment fail count on ENOMEM

rientjes · torvalds · commit dfef2ef4027b · 2016-05-20T17:58:30.000-07:00
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
@@ -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++;
