swapfile/vmscan: update comments related to vmscan functions

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 6beb625..bb7f796 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -656,8 +656,8 @@
 
 	if (!down_read_trylock(&mm->mmap_sem)) {
 		/*
-		 * Activate page so shrink_cache is unlikely to unmap its
-		 * ptes while lock is dropped, so swapoff can make progress.
+		 * Activate page so shrink_inactive_list is unlikely to unmap
+		 * its ptes while lock is dropped, so swapoff can make progress.
 		 */
 		activate_page(page);
 		unlock_page(page);