Merge remote-tracking branch 'cgroup/for-next'

[deliverable/linux.git] / kernel / cgroup.c

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 5e2e81ad9175cd08762d7e8e907caf61b64974ad..0c4db7908264bf5c55c2271f5dd4ec65f05503bf 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -5626,6 +5626,12 @@ int __init cgroup_init(void)
        BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
        BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));
 
+       /*
+        * The latency of the synchronize_sched() is too high for cgroups,
+        * avoid it at the cost of forcing all readers into the slow path.
+        */
+       rcu_sync_enter_start(&cgroup_threadgroup_rwsem.rss);
+
        get_user_ns(init_cgroup_ns.user_ns);
 
        mutex_lock(&cgroup_mutex);