Hello, Balbir. On Tue, Aug 09, 2016 at 05:02:47PM +1000, Balbir Singh wrote: > > Hmm? Where does mem_cgroup_iter grab cgroup_mutex? cgroup_mutex nests > > outside cgroup_threadgroup_rwsem or most other mutexes for that matter > > and isn't exposed from cgroup core. > > > > I based my theory on the code > > mem_cgroup_iter -> css_next_descendant_pre which asserts > > cgroup_assert_mutex_or_rcu_locked(), > > although you are right, we hold RCU lock while calling css_* routines. That's "or". The iterator can be called either with RCU lock or cgroup_mutex. cgroup core may use it under cgroup_mutex. Everyone else uses it with rcu. Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>