[PATCH 1/3] mm: introduce mem_cgroup_put() helper

From: Roman Gushchin
Date: Mon Jul 30 2018 - 14:02:03 EST


Introduce the mem_cgroup_put() helper, which helps to eliminate guarding
memcg css release with "#ifdef CONFIG_MEMCG" in multiple places.

Link: http://lkml.kernel.org/r/20180623000600.5818-2-guro@xxxxxx
Signed-off-by: Roman Gushchin <guro@xxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 6c6fb116e925..e53e00cdbe3f 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -375,6 +375,11 @@ struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css){
return css ? container_of(css, struct mem_cgroup, css) : NULL;
}

+static inline void mem_cgroup_put(struct mem_cgroup *memcg)
+{
+ css_put(&memcg->css);
+}
+
#define mem_cgroup_from_counter(counter, member) \
container_of(counter, struct mem_cgroup, member)

@@ -837,6 +842,10 @@ static inline bool task_in_mem_cgroup(struct task_struct *task,
return true;
}

+static inline void mem_cgroup_put(struct mem_cgroup *memcg)
+{
+}
+
static inline struct mem_cgroup *
mem_cgroup_iter(struct mem_cgroup *root,
struct mem_cgroup *prev,
--
2.14.4