mm: vmscan: fix documentation for page_check_references()

Commit b518154e ("mm/vmscan: protect the workingset on anonymous
LRU") requires to look twice for both mapped anon/file pages are used
more than once to take the decission of reclaim or activation.  Correct
the documentation accordingly.

Link: https://lkml.kernel.org/r/1646925640-21324-1-git-send-email-quic_charante@quicinc.comSigned-off-by: Charan Teja Kalla <quic_charante@quicinc.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmscan.c

@@ -1385,7 +1385,7 @@ static enum page_references page_check_references(struct page *page,
 		/*
 		 * All mapped pages start out with page table
 		 * references from the instantiating fault, so we need
-		 * to look twice if a mapped file page is used more
+		 * to look twice if a mapped file/anon page is used more
 		 * than once.
 		 *
 		 * Mark it and spare it for another trip around the