memcg: add zone_reclaim_stat

Introduce mem_cgroup_per_zone::reclaim_stat member and its statics
collecting function.

Now, get_scan_ratio() can calculate correct value on memcg reclaim.

[hugh@veritas.com: avoid reclaim_stat oops when disabled]
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 13 insertions, 14 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index d958d624d3ae..56fc7abe4d23 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -133,6 +133,9 @@ static DECLARE_RWSEM(shrinker_rwsem);
 static struct zone_reclaim_stat *get_reclaim_stat(struct zone *zone,
                                                   struct scan_control *sc)
 {
+        if (!scan_global_lru(sc))
+                return mem_cgroup_get_reclaim_stat(sc->mem_cgroup, zone);
+
         return &zone->reclaim_stat;
 }
 
@@ -1087,17 +1090,14 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
                 __mod_zone_page_state(zone, NR_INACTIVE_ANON,
                                                 -count[LRU_INACTIVE_ANON]);
 
-                if (scan_global_lru(sc)) {
+                if (scan_global_lru(sc))
                         zone->pages_scanned += nr_scan;
-                        reclaim_stat->recent_scanned[0] +=
-                                                      count[LRU_INACTIVE_ANON];
-                        reclaim_stat->recent_scanned[0] +=
-                                                      count[LRU_ACTIVE_ANON];
-                        reclaim_stat->recent_scanned[1] +=
-                                                      count[LRU_INACTIVE_FILE];
-                        reclaim_stat->recent_scanned[1] +=
-                                                      count[LRU_ACTIVE_FILE];
-                }
+
+                reclaim_stat->recent_scanned[0] += count[LRU_INACTIVE_ANON];
+                reclaim_stat->recent_scanned[0] += count[LRU_ACTIVE_ANON];
+                reclaim_stat->recent_scanned[1] += count[LRU_INACTIVE_FILE];
+                reclaim_stat->recent_scanned[1] += count[LRU_ACTIVE_FILE];
+
                 spin_unlock_irq(&zone->lru_lock);
 
                 nr_scanned += nr_scan;
@@ -1155,7 +1155,7 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
                         SetPageLRU(page);
                         lru = page_lru(page);
                         add_page_to_lru_list(zone, page, lru);
-                        if (PageActive(page) && scan_global_lru(sc)) {
+                        if (PageActive(page)) {
                                 int file = !!page_is_file_cache(page);
                                 reclaim_stat->recent_rotated[file]++;
                         }
@@ -1230,8 +1230,8 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
          */
         if (scan_global_lru(sc)) {
                 zone->pages_scanned += pgscanned;
-                reclaim_stat->recent_scanned[!!file] += pgmoved;
         }
+        reclaim_stat->recent_scanned[!!file] += pgmoved;
 
         if (file)
                 __mod_zone_page_state(zone, NR_ACTIVE_FILE, -pgmoved);
@@ -1272,8 +1272,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
          * This helps balance scan pressure between file and anonymous
          * pages in get_scan_ratio.
          */
-        if (scan_global_lru(sc))
-                reclaim_stat->recent_rotated[!!file] += pgmoved;
+        reclaim_stat->recent_rotated[!!file] += pgmoved;
 
         while (!list_empty(&l_inactive)) {
                 page = lru_to_page(&l_inactive);