1 files changed, 7 insertions, 4 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index c141b3e78071..62e7f62fb559 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 */
 
@@ -1245,6 +1248,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
                 list_add(&page->lru, &l_inactive);
         }
 
+        spin_lock_irq(&zone->lru_lock);
         /*
          * Count referenced pages from currently used mappings as
          * rotated, even though they are moved to the inactive list.
@@ -1260,7 +1264,6 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
 
         pgmoved = 0;
         lru = LRU_BASE + file * LRU_FILE;
-        spin_lock_irq(&zone->lru_lock);
         while (!list_empty(&l_inactive)) {
                 page = lru_to_page(&l_inactive);
                 prefetchw_prev_lru_page(page, &l_inactive, flags);
@@ -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;