1 files changed, 55 insertions, 52 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 25b0202c60df..8e1d72333e8a 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1514,21 +1514,52 @@ static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
 }
 
 /*
+ * Smallish @nr_to_scan's are deposited in @nr_saved_scan,
+ * until we collected @swap_cluster_max pages to scan.
+ */
+static unsigned long nr_scan_try_batch(unsigned long nr_to_scan,
+                                       unsigned long *nr_saved_scan)
+{
+        unsigned long nr;
+
+        *nr_saved_scan += nr_to_scan;
+        nr = *nr_saved_scan;
+
+        if (nr >= SWAP_CLUSTER_MAX)
+                *nr_saved_scan = 0;
+        else
+                nr = 0;
+
+        return nr;
+}
+
+/*
  * Determine how aggressively the anon and file LRU lists should be
  * scanned.  The relative value of each set of LRU lists is determined
  * by looking at the fraction of the pages scanned we did rotate back
  * onto the active list instead of evict.
  *
- * percent[0] specifies how much pressure to put on ram/swap backed
- * memory, while percent[1] determines pressure on the file LRUs.
+ * nr[0] = anon pages to scan; nr[1] = file pages to scan
  */
-static void get_scan_ratio(struct zone *zone, struct scan_control *sc,
-                                        unsigned long *percent)
+static void get_scan_count(struct zone *zone, struct scan_control *sc,
+                                        unsigned long *nr, int priority)
 {
         unsigned long anon, file, free;
         unsigned long anon_prio, file_prio;
         unsigned long ap, fp;
         struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
+        u64 fraction[2], denominator;
+        enum lru_list l;
+        int noswap = 0;
+
+        /* If we have no swap space, do not bother scanning anon pages. */
+        if (!sc->may_swap || (nr_swap_pages <= 0)) {
+                noswap = 1;
+                fraction[0] = 0;
+                fraction[1] = 1;
+                denominator = 1;
+                goto out;
+        }
 
         anon  = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_ANON) +
                 zone_nr_lru_pages(zone, sc, LRU_INACTIVE_ANON);
@@ -1540,9 +1571,10 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc,
                 /* If we have very few page cache pages,
                    force-scan anon pages. */
                 if (unlikely(file + free <= high_wmark_pages(zone))) {
-                        percent[0] = 100;
-                        percent[1] = 0;
-                        return;
+                        fraction[0] = 1;
+                        fraction[1] = 0;
+                        denominator = 1;
+                        goto out;
                 }
         }
 
@@ -1589,29 +1621,22 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc,
         fp = (file_prio + 1) * (reclaim_stat->recent_scanned[1] + 1);
         fp /= reclaim_stat->recent_rotated[1] + 1;
 
-        /* Normalize to percentages */
-        percent[0] = 100 * ap / (ap + fp + 1);
-        percent[1] = 100 - percent[0];
-}
-
-/*
- * Smallish @nr_to_scan's are deposited in @nr_saved_scan,
- * until we collected @swap_cluster_max pages to scan.
- */
-static unsigned long nr_scan_try_batch(unsigned long nr_to_scan,
-                                       unsigned long *nr_saved_scan)
-{
-        unsigned long nr;
-
-        *nr_saved_scan += nr_to_scan;
-        nr = *nr_saved_scan;
-
-        if (nr >= SWAP_CLUSTER_MAX)
-                *nr_saved_scan = 0;
-        else
-                nr = 0;
+        fraction[0] = ap;
+        fraction[1] = fp;
+        denominator = ap + fp + 1;
+out:
+        for_each_evictable_lru(l) {
+                int file = is_file_lru(l);
+                unsigned long scan;
 
-        return nr;
+                scan = zone_nr_lru_pages(zone, sc, l);
+                if (priority || noswap) {
+                        scan >>= priority;
+                        scan = div64_u64(scan * fraction[file], denominator);
+                }
+                nr[l] = nr_scan_try_batch(scan,
+                                          &reclaim_stat->nr_saved_scan[l]);
+        }
 }
 
 /*
@@ -1622,33 +1647,11 @@ static void shrink_zone(int priority, struct zone *zone,
 {
         unsigned long nr[NR_LRU_LISTS];
         unsigned long nr_to_scan;
-        unsigned long percent[2];       /* anon @ 0; file @ 1 */
         enum lru_list l;
         unsigned long nr_reclaimed = sc->nr_reclaimed;
         unsigned long nr_to_reclaim = sc->nr_to_reclaim;
-        struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
-        int noswap = 0;
-
-        /* If we have no swap space, do not bother scanning anon pages. */
-        if (!sc->may_swap || (nr_swap_pages <= 0)) {
-                noswap = 1;
-                percent[0] = 0;
-                percent[1] = 100;
-        } else
-                get_scan_ratio(zone, sc, percent);
 
-        for_each_evictable_lru(l) {
-                int file = is_file_lru(l);
-                unsigned long scan;
-
-                scan = zone_nr_lru_pages(zone, sc, l);
-                if (priority || noswap) {
-                        scan >>= priority;
-                        scan = (scan * percent[file]) / 100;
-                }
-                nr[l] = nr_scan_try_batch(scan,
-                                          &reclaim_stat->nr_saved_scan[l]);
-        }
+        get_scan_count(zone, sc, nr, priority);
 
         while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] ||
                                         nr[LRU_INACTIVE_FILE]) {