Re: [PATCH 1/2] sched/psi: Create the psimon kthread outside of cgroup_mutex

[Tejun Heo <tj@kernel.org>]

Hello.

> If this error path is reached (e.g. by racing pressure_write() with cgroup
> rmdir making of->priv NULL), the calling thread would sleep for an RCU grace
> period while holding cgroup_mutex, stalling all other cgroup operations.
>
> Could the trigger destruction be deferred until after cgroup_mutex is dropped,
> or handled asynchronously to avoid stalling the cgroup subsystem?

This is pre-existing - rmdir and cgroup.pressure disable already destroy
triggers under cgroup_mutex when draining open fds. Maybe something to
improve in the future.

Thanks.

--
tejun