1 files changed, 82 insertions, 5 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6f5c0c517c49..9ec5e12486a7 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -752,15 +752,13 @@ void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
 	/* Update memcg */
 	__mod_memcg_state(memcg, idx, val);
 
+	/* Update lruvec */
+	__this_cpu_add(pn->lruvec_stat_local->count[idx], val);
+
 	x = val + __this_cpu_read(pn->lruvec_stat_cpu->count[idx]);
 	if (unlikely(abs(x) > MEMCG_CHARGE_BATCH)) {
 		struct mem_cgroup_per_node *pi;
 
-		/*
-		 * Batch local counters to keep them in sync with
-		 * the hierarchical ones.
-		 */
-		__this_cpu_add(pn->lruvec_stat_local->count[idx], x);
 		for (pi = pn; pi; pi = parent_nodeinfo(pi, pgdat->node_id))
 			atomic_long_add(x, &pi->lruvec_stat[idx]);
 		x = 0;
@@ -3260,6 +3258,72 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
 	}
 }
 
+static void memcg_flush_percpu_vmstats(struct mem_cgroup *memcg, bool slab_only)
+{
+	unsigned long stat[MEMCG_NR_STAT];
+	struct mem_cgroup *mi;
+	int node, cpu, i;
+	int min_idx, max_idx;
+
+	if (slab_only) {
+		min_idx = NR_SLAB_RECLAIMABLE;
+		max_idx = NR_SLAB_UNRECLAIMABLE;
+	} else {
+		min_idx = 0;
+		max_idx = MEMCG_NR_STAT;
+	}
+
+	for (i = min_idx; i < max_idx; i++)
+		stat[i] = 0;
+
+	for_each_online_cpu(cpu)
+		for (i = min_idx; i < max_idx; i++)
+			stat[i] += per_cpu(memcg->vmstats_percpu->stat[i], cpu);
+
+	for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
+		for (i = min_idx; i < max_idx; i++)
+			atomic_long_add(stat[i], &mi->vmstats[i]);
+
+	if (!slab_only)
+		max_idx = NR_VM_NODE_STAT_ITEMS;
+
+	for_each_node(node) {
+		struct mem_cgroup_per_node *pn = memcg->nodeinfo[node];
+		struct mem_cgroup_per_node *pi;
+
+		for (i = min_idx; i < max_idx; i++)
+			stat[i] = 0;
+
+		for_each_online_cpu(cpu)
+			for (i = min_idx; i < max_idx; i++)
+				stat[i] += per_cpu(
+					pn->lruvec_stat_cpu->count[i], cpu);
+
+		for (pi = pn; pi; pi = parent_nodeinfo(pi, node))
+			for (i = min_idx; i < max_idx; i++)
+				atomic_long_add(stat[i], &pi->lruvec_stat[i]);
+	}
+}
+
+static void memcg_flush_percpu_vmevents(struct mem_cgroup *memcg)
+{
+	unsigned long events[NR_VM_EVENT_ITEMS];
+	struct mem_cgroup *mi;
+	int cpu, i;
+
+	for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
+		events[i] = 0;
+
+	for_each_online_cpu(cpu)
+		for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
+			events[i] += per_cpu(memcg->vmstats_percpu->events[i],
+					     cpu);
+
+	for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
+		for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
+			atomic_long_add(events[i], &mi->vmevents[i]);
+}
+
 #ifdef CONFIG_MEMCG_KMEM
 static int memcg_online_kmem(struct mem_cgroup *memcg)
 {
@@ -3309,7 +3373,14 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg)
 	if (!parent)
 		parent = root_mem_cgroup;
 
+	/*
+	 * Deactivate and reparent kmem_caches. Then flush percpu
+	 * slab statistics to have precise values at the parent and
+	 * all ancestor levels. It's required to keep slab stats
+	 * accurate after the reparenting of kmem_caches.
+	 */
 	memcg_deactivate_kmem_caches(memcg, parent);
+	memcg_flush_percpu_vmstats(memcg, true);
 
 	kmemcg_id = memcg->kmemcg_id;
 	BUG_ON(kmemcg_id < 0);
@@ -4682,6 +4753,12 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg)
 {
 	int node;
 
+	/*
+	 * Flush percpu vmstats and vmevents to guarantee the value correctness
+	 * on parent's and all ancestor levels.
+	 */
+	memcg_flush_percpu_vmstats(memcg, false);
+	memcg_flush_percpu_vmevents(memcg);
 	for_each_node(node)
 		free_mem_cgroup_per_node_info(memcg, node);
 	free_percpu(memcg->vmstats_percpu);