Merge branch 'locking/urgent' into locking/core, to pick up fixes

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

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 5e8dab5..de1c1bd 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -5606,6 +5606,12 @@ 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);