memcg: add inactive_anon_is_low()

The inactive_anon_is_low() is key component of active/inactive anon
balancing on reclaim.  However current inactive_anon_is_low() function
only consider global reclaim.

Therefore, we need following ugly scan_global_lru() condition.

	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;

it cause that memcg reclaim always deactivate pages when shrink_list() is
called.  To make mem_cgroup_inactive_anon_is_low() improve active/inactive
anon balancing of memcgroup.

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: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: "Pekka Enberg" <penberg@cs.helsinki.fi>
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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 68 insertions, 15 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 457d671029b8..6611328460e9 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -156,6 +156,9 @@ struct mem_cgroup {
         unsigned long   last_oom_jiffies;
         int             obsolete;
         atomic_t        refcnt;
+
+        unsigned int inactive_ratio;
+
         /*
          * statistics. This must be placed at the end of memcg.
          */
@@ -431,6 +434,20 @@ long mem_cgroup_calc_reclaim(struct mem_cgroup *mem, struct zone *zone,
         return (nr_pages >> priority);
 }
 
+int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone)
+{
+        unsigned long active;
+        unsigned long inactive;
+
+        inactive = mem_cgroup_get_all_zonestat(memcg, LRU_INACTIVE_ANON);
+        active = mem_cgroup_get_all_zonestat(memcg, LRU_ACTIVE_ANON);
+
+        if (inactive * memcg->inactive_ratio < active)
+                return 1;
+
+        return 0;
+}
+
 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
                                         struct list_head *dst,
                                         unsigned long *scanned, int order,
@@ -1360,6 +1377,29 @@ int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
         return 0;
 }
 
+/*
+ * The inactive anon list should be small enough that the VM never has to
+ * do too much work, but large enough that each inactive page has a chance
+ * to be referenced again before it is swapped out.
+ *
+ * this calculation is straightforward porting from
+ * page_alloc.c::setup_per_zone_inactive_ratio().
+ * it describe more detail.
+ */
+static void mem_cgroup_set_inactive_ratio(struct mem_cgroup *memcg)
+{
+        unsigned int gb, ratio;
+
+        gb = res_counter_read_u64(&memcg->res, RES_LIMIT) >> 30;
+        if (gb)
+                ratio = int_sqrt(10 * gb);
+        else
+                ratio = 1;
+
+        memcg->inactive_ratio = ratio;
+
+}
+
 static DEFINE_MUTEX(set_limit_mutex);
 
 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
@@ -1398,6 +1438,10 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
                                 GFP_KERNEL, false);
                 if (!progress)                  retry_count--;
         }
+
+        if (!ret)
+                mem_cgroup_set_inactive_ratio(memcg);
+
         return ret;
 }
 
@@ -1982,7 +2026,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
                 res_counter_init(&mem->res, NULL);
                 res_counter_init(&mem->memsw, NULL);
         }
-
+        mem_cgroup_set_inactive_ratio(mem);
         mem->last_scanned_child = NULL;
 
         return &mem->css;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index e2b31a522a66..b2bc06bffcfb 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1310,14 +1310,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
         pagevec_release(&pvec);
 }
 
-/**
- * inactive_anon_is_low - check if anonymous pages need to be deactivated
- * @zone: zone to check
- *
- * Returns true if the zone does not have enough inactive anon pages,
- * meaning some active anon pages need to be deactivated.
- */
-static int inactive_anon_is_low(struct zone *zone)
+static int inactive_anon_is_low_global(struct zone *zone)
 {
         unsigned long active, inactive;
 
@@ -1330,6 +1323,25 @@ static int inactive_anon_is_low(struct zone *zone)
         return 0;
 }
 
+/**
+ * inactive_anon_is_low - check if anonymous pages need to be deactivated
+ * @zone: zone to check
+ * @sc:   scan control of this context
+ *
+ * Returns true if the zone does not have enough inactive anon pages,
+ * meaning some active anon pages need to be deactivated.
+ */
+static int inactive_anon_is_low(struct zone *zone, struct scan_control *sc)
+{
+        int low;
+
+        if (scan_global_lru(sc))
+                low = inactive_anon_is_low_global(zone);
+        else
+                low = mem_cgroup_inactive_anon_is_low(sc->mem_cgroup, zone);
+        return low;
+}
+
 static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
         struct zone *zone, struct scan_control *sc, int priority)
 {
@@ -1340,8 +1352,7 @@ static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
                 return 0;
         }
 
-        if (lru == LRU_ACTIVE_ANON &&
-            (!scan_global_lru(sc) || inactive_anon_is_low(zone))) {
+        if (lru == LRU_ACTIVE_ANON && inactive_anon_is_low(zone, sc)) {
                 shrink_active_list(nr_to_scan, zone, sc, priority, file);
                 return 0;
         }
@@ -1509,9 +1520,7 @@ static void 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))
+        if (inactive_anon_is_low(zone, sc))
                 shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0);
 
         throttle_vm_writeout(sc->gfp_mask);
@@ -1807,7 +1816,7 @@ loop_again:
                          * Do some background aging of the anon list, to give
                          * pages a chance to be referenced before reclaiming.
                          */
-                        if (inactive_anon_is_low(zone))
+                        if (inactive_anon_is_low(zone, &sc))
                                 shrink_active_list(SWAP_CLUSTER_MAX, zone,
                                                         &sc, priority, 0);