memcg: generate file modified notifications on "memory.events"

cgroup core only recently grew generic notification support.  Wire up
"memory.events" so that it triggers a file modified event whenever its
content changes.

v2: Refreshed on top of mem_cgroup relocation.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zefan <lizefan@huawei.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 9aa7820c2177..c83c699a6605 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -213,6 +213,9 @@ struct mem_cgroup {
         /* OOM-Killer disable */
         int             oom_kill_disable;
 
+        /* handle for "memory.events" */
+        struct cgroup_file events_file;
+
         /* protect arrays of thresholds */
         struct mutex thresholds_lock;
 
@@ -286,6 +289,7 @@ static inline void mem_cgroup_events(struct mem_cgroup *memcg,
                        unsigned int nr)
 {
         this_cpu_add(memcg->stat->events[idx], nr);
+        cgroup_file_notify(&memcg->events_file);
 }
 
 bool mem_cgroup_low(struct mem_cgroup *root, struct mem_cgroup *memcg);