[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <YAMDUQ7JX2Fr8D+/@hirez.programming.kicks-ass.net>
Date: Sat, 16 Jan 2021 16:16:33 +0100
From: Peter Zijlstra <peterz@...radead.org>
To: Lai Jiangshan <jiangshanlai@...il.com>
Cc: Valentin Schneider <valentin.schneider@....com>,
Ingo Molnar <mingo@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
LKML <linux-kernel@...r.kernel.org>, Qian Cai <cai@...hat.com>,
Vincent Donnefort <vincent.donnefort@....com>,
Dexuan Cui <decui@...rosoft.com>,
"Paul E. McKenney" <paulmck@...nel.org>,
Vincent Guittot <vincent.guittot@...aro.org>,
Steven Rostedt <rostedt@...dmis.org>, Tejun Heo <tj@...nel.org>
Subject: Re: [PATCH 3/4] workqueue: Tag bound workers with KTHREAD_IS_PER_CPU
On Sat, Jan 16, 2021 at 10:45:04PM +0800, Lai Jiangshan wrote:
> On Sat, Jan 16, 2021 at 8:45 PM Peter Zijlstra <peterz@...radead.org> wrote:
> > It is also the exact sequence normal per-cpu threads (smpboot) use to
> > preserve affinity.
>
> Other per-cpu threads normally do short-live works. wq's work can be
> lengthy, cpu-intensive, heavy-lock-acquiring or even call
> get_online_cpus() which might result in a deadlock with kthread_park().
kthread_park() is called by the migration thread running the
workqueue_online_cpu() callback.
kthread_parkme() is called by the worker thread, after it completes a
work and has no locks held from that context.
Powered by blists - more mailing lists