From: Tejun Heo <tj@kernel.org>
To: Waiman Long <longman@redhat.com>
Cc: Qais Yousef <qais.yousef@arm.com>,
Xuewen Yan <xuewen.yan@unisoc.com>,
rafael@kernel.org, viresh.kumar@linaro.org, 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,
bristot@redhat.com, linux-kernel@vger.kernel.org,
ke.wang@unisoc.com, xuewyan@foxmail.com,
linux-pm@vger.kernel.org
Subject: Re: [PATCH] sched/schedutil: Fix deadlock between cpuset and cpu hotplug when using schedutil
Date: Tue, 12 Jul 2022 17:00:52 -1000 [thread overview]
Message-ID: <Ys41ZF5TmSnLLNRB@slm.duckdns.org> (raw)
In-Reply-To: <c1426573-92a7-9f0d-a6b8-aa612248b9a9@redhat.com>
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
next prev parent reply other threads:[~2022-07-13 3:01 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-05 12:37 Xuewen Yan
2022-07-11 7:21 ` Xuewen Yan
2022-07-11 7:32 ` Lukasz Luba
2022-07-11 7:43 ` Xuewen Yan
2022-07-11 7:47 ` Viresh Kumar
2022-07-11 7:50 ` Lukasz Luba
2022-07-11 17:46 ` Qais Yousef
2022-07-11 20:58 ` Tejun Heo
2022-07-11 21:11 ` Steven Rostedt
2022-07-12 5:42 ` Xuewen Yan
2022-07-12 5:57 ` Xuewen Yan
2022-07-13 3:02 ` Waiman Long
2022-07-12 12:57 ` Qais Yousef
2022-07-12 16:13 ` Tejun Heo
2022-07-12 17:14 ` Qais Yousef
2022-07-27 22:01 ` Peter Zijlstra
2022-07-27 22:05 ` Tejun Heo
2022-07-13 2:49 ` Waiman Long
2022-07-13 3:00 ` Tejun Heo [this message]
2022-07-20 7:45 ` Xuewen Yan
2022-07-27 20:09 ` Tejun Heo
2022-07-29 7:33 ` Xuewen Yan
2022-07-29 8:39 ` Qais Yousef
2022-07-29 19:59 ` Tejun Heo
2022-08-09 2:02 ` Xuewen Yan
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