[PATCH v2 10/28] mm: memcg: introduce mod_lruvec_memcg_state()

[Roman Gushchin <guro@fb.com>]

To prepare for per-object accounting of slab objects, let's introduce
__mod_lruvec_memcg_state() and mod_lruvec_memcg_state() helpers,
which are similar to mod_lruvec_state(), but do not update global
node counters, only lruvec and per-cgroup.

It's necessary because soon node slab counters will be used for
accounting of all memory used by slab pages, however on memcg level
only the actually used memory will be counted. The free space will be
shared between all cgroups, so it can't be accounted to any
specific cgroup.

Signed-off-by: Roman Gushchin <guro@fb.com>
---
 include/linux/memcontrol.h | 22 ++++++++++++++++++++++
 mm/memcontrol.c            | 37 +++++++++++++++++++++++++++----------
 2 files changed, 49 insertions(+), 10 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 37d4f418e336..73c2a7d32862 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -694,6 +694,8 @@ static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
 
 void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
 			int val);
+void __mod_lruvec_memcg_state(struct lruvec *lruvec, enum node_stat_item idx,
+			      int val);
 void __mod_lruvec_obj_state(void *p, enum node_stat_item idx, int val);
 void mod_memcg_obj_state(void *p, int idx, int val);
 
@@ -707,6 +709,16 @@ static inline void mod_lruvec_state(struct lruvec *lruvec,
 	local_irq_restore(flags);
 }
 
+static inline void mod_lruvec_memcg_state(struct lruvec *lruvec,
+					  enum node_stat_item idx, int val)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__mod_lruvec_memcg_state(lruvec, idx, val);
+	local_irq_restore(flags);
+}
+
 static inline void __mod_lruvec_page_state(struct page *page,
 					   enum node_stat_item idx, int val)
 {
@@ -1104,6 +1116,16 @@ static inline void mod_lruvec_state(struct lruvec *lruvec,
 	mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
 }
 
+static inline void __mod_lruvec_memcg_state(struct lruvec *lruvec,
+					    enum node_stat_item idx, int val)
+{
+}
+
+static inline void mod_lruvec_memcg_state(struct lruvec *lruvec,
+					  enum node_stat_item idx, int val)
+{
+}
+
 static inline void __mod_lruvec_page_state(struct page *page,
 					   enum node_stat_item idx, int val)
 {
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index cbf01cc0cbac..730f230cee6a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -712,16 +712,16 @@ parent_nodeinfo(struct mem_cgroup_per_node *pn, int nid)
 }
 
 /**
- * __mod_lruvec_state - update lruvec memory statistics
+ * __mod_lruvec_memcg_state - update lruvec memory statistics
  * @lruvec: the lruvec
  * @idx: the stat item
  * @val: delta to add to the counter, can be negative
  *
  * The lruvec is the intersection of the NUMA node and a cgroup. This
- * function updates the all three counters that are affected by a
- * change of state at this level: per-node, per-cgroup, per-lruvec.
+ * function updates the two of three counters that are affected by a
+ * change of state at this level: per-cgroup and per-lruvec.
  */
-void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
+void __mod_lruvec_memcg_state(struct lruvec *lruvec, enum node_stat_item idx,
 			int val)
 {
 	pg_data_t *pgdat = lruvec_pgdat(lruvec);
@@ -729,12 +729,6 @@ void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
 	struct mem_cgroup *memcg;
 	long x;
 
-	/* Update node */
-	__mod_node_page_state(pgdat, idx, val);
-
-	if (mem_cgroup_disabled())
-		return;
-
 	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
 	memcg = pn->memcg;
 
@@ -755,6 +749,29 @@ void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
 	__this_cpu_write(pn->lruvec_stat_cpu->count[idx], x);
 }
 
+/**
+ * __mod_lruvec_state - update lruvec memory statistics
+ * @lruvec: the lruvec
+ * @idx: the stat item
+ * @val: delta to add to the counter, can be negative
+ *
+ * The lruvec is the intersection of the NUMA node and a cgroup. This
+ * function updates the all three counters that are affected by a
+ * change of state at this level: per-node, per-cgroup, per-lruvec.
+ */
+void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
+			int val)
+{
+	pg_data_t *pgdat = lruvec_pgdat(lruvec);
+
+	/* Update node */
+	__mod_node_page_state(pgdat, idx, val);
+
+	/* Update per-cgroup and per-lruvec stats */
+	if (!mem_cgroup_disabled())
+		__mod_lruvec_memcg_state(lruvec, idx, val);
+}
+
 void __mod_lruvec_obj_state(void *p, enum node_stat_item idx, int val)
 {
 	pg_data_t *pgdat = page_pgdat(virt_to_page(p));
-- 
2.24.1