1 files changed, 55 insertions, 52 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 25b0202c60d..8e1d72333e8 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]) {