Messages in this thread | | | Date | Tue, 12 Jul 2022 17:00:52 -1000 | From | Tejun Heo <> | Subject | Re: [PATCH] sched/schedutil: Fix deadlock between cpuset and cpu hotplug when using schedutil |
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On Tue, Jul 12, 2022 at 10:49:57PM -0400, Waiman Long wrote: > > Well, the only thing I can think of is always grabbing cpus_read_lock() > > before grabbing threadgroup_rwsem. Waiman, what do you think? > > That is a possible solution as cpus_read_lock() is rather lightweight. It is > a good practice to acquire it first.
On a similar note, I think we probably should re-enable percpu operations on threadgroup_rwsem too by default and allow users who are affected by slower write path operations to opt-in. After the new CLONE_INTO_CGROUP which doesn't need the rwsem, we have far fewer write lockers after all.
Thanks.
-- tejun
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