From: Zhang Qiao <zhangqiao22@huawei.com>
To: Chuyi Zhou <zhouchuyi@bytedance.com>, <mingo@redhat.com>,
<peterz@infradead.org>, <juri.lelli@redhat.com>,
<vincent.guittot@linaro.org>, <dietmar.eggemann@arm.com>,
<rostedt@goodmis.org>, <bsegall@google.com>, <mgorman@suse.de>,
<vschneid@redhat.com>
Cc: <chengming.zhou@linux.dev>, <linux-kernel@vger.kernel.org>,
<joshdon@google.com>
Subject: Re: [PATCH 1/2] sched/fair: Decrease cfs bandwidth usage in task_group destruction
Date: Mon, 22 Jul 2024 16:16:12 +0800 [thread overview]
Message-ID: <5607f1e2-b235-4eda-a9d9-2e9519db3f74@huawei.com> (raw)
In-Reply-To: <e4e3a63d-a5f2-4c1d-a9da-4ddbc3693450@bytedance.com>
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.
next prev parent reply other threads:[~2024-07-22 8:16 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-21 12:52 [PATCH 0/2] minor cpu bandwidth control fix Chuyi Zhou
2024-07-21 12:52 ` [PATCH 1/2] sched/fair: Decrease cfs bandwidth usage in task_group destruction Chuyi Zhou
2024-07-22 3:47 ` Zhang Qiao
2024-07-22 6:04 ` Chuyi Zhou
2024-07-22 7:16 ` Zhang Qiao
2024-07-22 7:46 ` Chuyi Zhou
2024-07-22 8:16 ` Zhang Qiao [this message]
2024-07-22 22:20 ` Benjamin Segall
2024-07-21 12:52 ` [PATCH 2/2] sched/core: Avoid unnecessary update in tg_set_cfs_bandwidth Chuyi Zhou
2024-07-22 7:21 ` Chengming Zhou
2024-07-22 22:24 ` Benjamin Segall
2024-07-23 2:34 ` Chuyi Zhou
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