vmscan: fix get_scan_ratio() comment

[linux-2.6-omap-h63xx.git] / mm / vmscan.c

diff --git a/mm/vmscan.c b/mm/vmscan.c
index c141b3e780719d314a5010f702190d8a9c56c23b..7ea1440b53db23350112cb1a46c592542807e4ac 100644 (file)
--- 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;