Re: [PATCH 1/2] sched/fair: Decrease cfs bandwidth usage in task_group destruction

[Zhang Qiao]

在 2024/7/22 15:46, Chuyi Zhou 写道:
>>>
>>> Thanks for your information.
>>>
>>> I think maybe cfs_bandwidth_usage_dec() should be moved to other more suitable places where could
>>> hold hotplug lock(e.g. cpu_cgroup_css_released()). I would do some test to verify it.
>>>
>>
>> The cpu_cgroup_css_released() also doesn't seem to be in the cpu hotplug lock-holding context.
>>
> 
> IIUC, cpus_read_lock/cpus_read_unlock can be called in cpu_cgroup_css_released() right? But cfs
> bandwidth destroy maybe run in a rcu callback since task group list is protected by RCU so we could not
> get the lock. Did I miss something important?


Okay, you're right. I ignored that we can't hold the hotplug lock in an rcu callback.