vmscan: ZVC updates in shrink_active_list() can be done once

This effectively lifts the unit of updates to nr_inactive_* and
pgdeactivate from PAGEVEC_SIZE=14 to SWAP_CLUSTER_MAX=32, or
MAX_ORDER_NR_PAGES=1024 for reclaim_zone().

Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 8 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index d4da097533ce..7592d8eb1148 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1223,7 +1223,6 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
                         struct scan_control *sc, int priority, int file)
 {
         unsigned long pgmoved;
-        int pgdeactivate = 0;
         unsigned long pgscanned;
         LIST_HEAD(l_hold);      /* The pages which were snipped off */
         LIST_HEAD(l_inactive);
@@ -1252,7 +1251,7 @@ 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;
+        pgmoved = 0;  /* count referenced (mapping) mapped pages */
         while (!list_empty(&l_hold)) {
                 cond_resched();
                 page = lru_to_page(&l_hold);
@@ -1286,7 +1285,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
          */
         reclaim_stat->recent_rotated[!!file] += pgmoved;
 
-        pgmoved = 0;
+        pgmoved = 0;  /* count pages moved to inactive list */
         while (!list_empty(&l_inactive)) {
                 page = lru_to_page(&l_inactive);
                 prefetchw_prev_lru_page(page, &l_inactive, flags);
@@ -1299,10 +1298,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
                 mem_cgroup_add_lru_list(page, lru);
                 pgmoved++;
                 if (!pagevec_add(&pvec, page)) {
-                        __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
                         spin_unlock_irq(&zone->lru_lock);
-                        pgdeactivate += pgmoved;
-                        pgmoved = 0;
                         if (buffer_heads_over_limit)
                                 pagevec_strip(&pvec);
                         __pagevec_release(&pvec);
@@ -1310,9 +1306,8 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
                 }
         }
         __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
-        pgdeactivate += pgmoved;
         __count_zone_vm_events(PGREFILL, zone, pgscanned);
-        __count_vm_events(PGDEACTIVATE, pgdeactivate);
+        __count_vm_events(PGDEACTIVATE, pgmoved);
         spin_unlock_irq(&zone->lru_lock);
         if (buffer_heads_over_limit)
                 pagevec_strip(&pvec);