1 files changed, 2 insertions, 49 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 49e5aa6abca6..701cbee9acba 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -324,11 +324,6 @@ struct mem_cgroup {
 	 * percpu counter.
 	 */
 	struct mem_cgroup_stat_cpu __percpu *stat;
-	/*
-	 * used when a cpu is offlined or other synchronizations
-	 * See mem_cgroup_read_stat().
-	 */
-	struct mem_cgroup_stat_cpu nocpu_base;
 	spinlock_t pcp_counter_lock;
 
 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
@@ -834,15 +829,8 @@ static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
 	long val = 0;
 	int cpu;
 
-	get_online_cpus();
-	for_each_online_cpu(cpu)
+	for_each_possible_cpu(cpu)
 		val += per_cpu(memcg->stat->count[idx], cpu);
-#ifdef CONFIG_HOTPLUG_CPU
-	spin_lock(&memcg->pcp_counter_lock);
-	val += memcg->nocpu_base.count[idx];
-	spin_unlock(&memcg->pcp_counter_lock);
-#endif
-	put_online_cpus();
 	return val;
 }
 
@@ -852,15 +840,8 @@ static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
 	unsigned long val = 0;
 	int cpu;
 
-	get_online_cpus();
-	for_each_online_cpu(cpu)
+	for_each_possible_cpu(cpu)
 		val += per_cpu(memcg->stat->events[idx], cpu);
-#ifdef CONFIG_HOTPLUG_CPU
-	spin_lock(&memcg->pcp_counter_lock);
-	val += memcg->nocpu_base.events[idx];
-	spin_unlock(&memcg->pcp_counter_lock);
-#endif
-	put_online_cpus();
 	return val;
 }
 
@@ -2210,37 +2191,12 @@ static void drain_all_stock(struct mem_cgroup *root_memcg)
 	mutex_unlock(&percpu_charge_mutex);
 }
 
-/*
- * This function drains percpu counter value from DEAD cpu and
- * move it to local cpu. Note that this function can be preempted.
- */
-static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
-{
-	int i;
-
-	spin_lock(&memcg->pcp_counter_lock);
-	for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
-		long x = per_cpu(memcg->stat->count[i], cpu);
-
-		per_cpu(memcg->stat->count[i], cpu) = 0;
-		memcg->nocpu_base.count[i] += x;
-	}
-	for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
-		unsigned long x = per_cpu(memcg->stat->events[i], cpu);
-
-		per_cpu(memcg->stat->events[i], cpu) = 0;
-		memcg->nocpu_base.events[i] += x;
-	}
-	spin_unlock(&memcg->pcp_counter_lock);
-}
-
 static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
 					unsigned long action,
 					void *hcpu)
 {
 	int cpu = (unsigned long)hcpu;
 	struct memcg_stock_pcp *stock;
-	struct mem_cgroup *iter;
 
 	if (action == CPU_ONLINE)
 		return NOTIFY_OK;
@@ -2248,9 +2204,6 @@ static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
 	if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
 		return NOTIFY_OK;
 
-	for_each_mem_cgroup(iter)
-		mem_cgroup_drain_pcp_counter(iter, cpu);
-
 	stock = &per_cpu(memcg_stock, cpu);
 	drain_stock(stock);
 	return NOTIFY_OK;