vmscan: second chance replacement for anonymous pages

[deliverable/linux.git] / mm / vmscan.c

diff --git a/mm/vmscan.c b/mm/vmscan.c
index d10d2f9a33f39610bea63361b5c7340f2848f019..c82ee9a33cfc7ca2e2ef56b6091a3c2fff96c62b 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1090,6 +1090,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
                __mod_zone_page_state(zone, NR_ACTIVE_ANON, -pgmoved);
        spin_unlock_irq(&zone->lru_lock);
 
+       pgmoved = 0;
        while (!list_empty(&l_hold)) {
                cond_resched();
                page = lru_to_page(&l_hold);
@@ -1097,6 +1098,13 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
                list_add(&page->lru, &l_inactive);
        }
 
+       /*
+        * Count the referenced pages as rotated, even when they are moved
+        * to the inactive list.  This helps balance scan pressure between
+        * file and anonymous pages in get_scan_ratio.
+        */
+       zone->recent_rotated[!!file] += pgmoved;
+
        /*
         * Now put the pages back on the appropriate [file or anon] inactive
         * and active lists.
@@ -1158,7 +1166,6 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
                }
        }
        __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
-       zone->recent_rotated[!!file] += pgmoved;
 
        __count_zone_vm_events(PGREFILL, zone, pgscanned);
        __count_vm_events(PGDEACTIVATE, pgdeactivate);
@@ -1174,7 +1181,13 @@ static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
 {
        int file = is_file_lru(lru);
 
-       if (lru == LRU_ACTIVE_ANON || lru == LRU_ACTIVE_FILE) {
+       if (lru == LRU_ACTIVE_FILE) {
+               shrink_active_list(nr_to_scan, zone, sc, priority, file);
+               return 0;
+       }
+
+       if (lru == LRU_ACTIVE_ANON &&
+           (!scan_global_lru(sc) || inactive_anon_is_low(zone))) {
                shrink_active_list(nr_to_scan, zone, sc, priority, file);
                return 0;
        }
@@ -1310,8 +1323,8 @@ static unsigned long shrink_zone(int priority, struct zone *zone,
                }
        }
 
-       while (nr[LRU_ACTIVE_ANON] || nr[LRU_INACTIVE_ANON] ||
-                       nr[LRU_ACTIVE_FILE] || nr[LRU_INACTIVE_FILE]) {
+       while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] ||
+                                       nr[LRU_INACTIVE_FILE]) {
                for_each_lru(l) {
                        if (nr[l]) {
                                nr_to_scan = min(nr[l],
@@ -1324,6 +1337,15 @@ static unsigned long shrink_zone(int priority, struct zone *zone,
                }
        }
 
+       /*
+        * Even if we did not try to evict anon pages at all, we want to
+        * rebalance the anon lru active/inactive ratio.
+        */
+       if (!scan_global_lru(sc) || inactive_anon_is_low(zone))
+               shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0);
+       else if (!scan_global_lru(sc))
+               shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0);
+
        throttle_vm_writeout(sc->gfp_mask);
        return nr_reclaimed;
 }
@@ -1617,6 +1639,14 @@ loop_again:
                            priority != DEF_PRIORITY)
                                continue;
 
+                       /*
+                        * Do some background aging of the anon list, to give
+                        * pages a chance to be referenced before reclaiming.
+                        */
+                       if (inactive_anon_is_low(zone))
+                               shrink_active_list(SWAP_CLUSTER_MAX, zone,
+                                                       &sc, priority, 0);
+
                        if (!zone_watermark_ok(zone, order, zone->pages_high,
                                               0, 0)) {
                                end_zone = i;