1 files changed, 6 insertions, 3 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index c141b3e78071..7ea1440b53db 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -623,6 +623,8 @@ static unsigned long shrink_page_list(struct list_head *page_list,
                  * Try to allocate it some swap space here.
                  */
                 if (PageAnon(page) && !PageSwapCache(page)) {
+                        if (!(sc->gfp_mask & __GFP_IO))
+                                goto keep_locked;
                         switch (try_to_munlock(page)) {
                         case SWAP_FAIL:         /* shouldn't happen */
                         case SWAP_AGAIN:
@@ -634,6 +636,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
                         }
                         if (!add_to_swap(page, GFP_ATOMIC))
                                 goto activate_locked;
+                        may_enter_fs = 1;
                 }
 #endif /* CONFIG_SWAP */
 
@@ -1386,9 +1389,9 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc,
         file_prio = 200 - sc->swappiness;
 
         /*
-         *                  anon       recent_rotated[0]
-         * %anon = 100 * ----------- / ----------------- * IO cost
-         *               anon + file      rotate_sum
+         * The amount of pressure on anon vs file pages is inversely
+         * proportional to the fraction of recently scanned pages on
+         * each list that were recently referenced and in active use.
          */
         ap = (anon_prio + 1) * (zone->recent_scanned[0] + 1);
         ap /= zone->recent_rotated[0] + 1;