[PATCH v2 1/5] memcg: make nocpu_base available for non hotplug

[Glauber Costa <glommer@parallels.com>]

We are using nocpu_base to accumulate charges on the main counters
during cpu hotplug. I have a similar need, which is transferring charges
to the root cgroup when lazily enabling memcg. Because system wide
information is not kept per-cpu, it is hard to distribute it. This field
works well for this. So we need to make it available for all usages, not
only hotplug cases.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
---
 mm/memcontrol.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 669d16a..b8b363f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -921,11 +921,11 @@ static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
 	get_online_cpus();
 	for_each_online_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;
 }
@@ -945,11 +945,11 @@ static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
 
 	for_each_online_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
+
 	return val;
 }
 
-- 
1.8.1.2

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