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, 29 insertions, 0 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 313247e6c503..7b7f4dc05035 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -103,6 +103,8 @@ struct mem_cgroup_per_zone {
          */
         struct list_head        lists[NR_LRU_LISTS];
         unsigned long           count[NR_LRU_LISTS];
+
+        struct zone_reclaim_stat reclaim_stat;
 };
 /* Macro for accessing counter */
 #define MEM_CGROUP_ZSTAT(mz, idx)       ((mz)->count[(idx)])
@@ -458,6 +460,33 @@ unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
         return MEM_CGROUP_ZSTAT(mz, lru);
 }
 
+struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
+                                                      struct zone *zone)
+{
+        int nid = zone->zone_pgdat->node_id;
+        int zid = zone_idx(zone);
+        struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
+
+        return &mz->reclaim_stat;
+}
+
+struct zone_reclaim_stat *
+mem_cgroup_get_reclaim_stat_from_page(struct page *page)
+{
+        struct page_cgroup *pc;
+        struct mem_cgroup_per_zone *mz;
+
+        if (mem_cgroup_disabled())
+                return NULL;
+
+        pc = lookup_page_cgroup(page);
+        mz = page_cgroup_zoneinfo(pc);
+        if (!mz)
+                return NULL;
+
+        return &mz->reclaim_stat;
+}
+
 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
                                         struct list_head *dst,
                                         unsigned long *scanned, int order,