Re: [PATCH 2/3 cgroup/for-6.16] sched_ext: Introduce cgroup_lifetime_notifier

[Michal Koutný]

On Wed, May 14, 2025 at 12:44:44AM -0400, Tejun Heo <tj@xxxxxxxxxx> wrote:
> Other subsystems may make use of the cgroup hierarchy with the cgroup_bpf
> support being one such example. For such a feature, it's useful to be able
<snip>

> other uses are planned.
<snip>

> @@ -5753,6 +5765,15 @@ static struct cgroup *cgroup_create(stru
>  			goto out_psi_free;
>  	}
>  
> +	ret = blocking_notifier_call_chain_robust(&cgroup_lifetime_notifier,
> +						  CGROUP_LIFETIME_ONLINE,
> +						  CGROUP_LIFETIME_OFFLINE, cgrp);

This is with cgroup_mutex taken.

Wouldn't it be more prudent to start with atomic or raw notifier chain?
(To prevent future unwitting expansion of cgroup_mutex.)


Thanks,
Michal

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