From: Tejun Heo <tj@kernel.org>
To: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: linux-kernel@vger.kernel.org, tangchen <tangchen@cn.fujitsu.com>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 02/12] workqueue: disallow set_cpus_allowed_ptr() from work item
Date: Wed, 26 Sep 2012 11:12:30 -0700 [thread overview]
Message-ID: <20120926181230.GC12544@google.com> (raw)
In-Reply-To: <1348680043-5077-3-git-send-email-laijs@cn.fujitsu.com>
On Thu, Sep 27, 2012 at 01:20:33AM +0800, Lai Jiangshan wrote:
> workers depend on local-wake-up, if a work function change its CPU, it will
> corrupt workqueue, disallow this behavior.
>
> When set_cpus_allowed_ptr() is called from workqueue.c in worker_thread(),
> we clear the PF_WQ_WORKER before set_cpus_allowed_ptr() and set it back
> after. (rescuer thread has no PF_WQ_WORKER, skip this behavior)
>
> It prevents other/future BUGs like https://bugzilla.kernel.org/show_bug.cgi?id=47301.
Hmmm... maybe. We better clear up PF_THREAD_BOUND semantics first
tho.
I think the two possible choices are,
* Don't allow set_cpus_allowed_ptr() at all and make the caller
responsible for turning it off if it explicitly wants to change
cpus_allowed.
* Don't allow changing affinity from userland.
Peter, Thomas?
--
tejun
next prev parent reply other threads:[~2012-09-26 18:12 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-26 17:20 [PATCH 00/12] workqueue: simple cleanups Lai Jiangshan
2012-09-26 17:20 ` [PATCH 01/12] workqueue: add WORKER_RESCUER Lai Jiangshan
2012-09-26 18:07 ` Tejun Heo
2012-09-28 10:11 ` Lai Jiangshan
2012-09-26 17:20 ` [PATCH 02/12] workqueue: disallow set_cpus_allowed_ptr() from work item Lai Jiangshan
2012-09-26 18:12 ` Tejun Heo [this message]
2012-09-26 17:20 ` [PATCH 03/12] workqueue: remove WORKER_PREP from rescuer Lai Jiangshan
2012-09-26 18:24 ` Tejun Heo
2012-09-28 10:04 ` Lai Jiangshan
2012-09-30 7:39 ` Tejun Heo
2012-09-26 17:20 ` [PATCH 04/12] workqueue: simplify is_chained_work() Lai Jiangshan
2012-09-26 18:28 ` Tejun Heo
2012-09-28 9:52 ` Lai Jiangshan
2012-09-30 7:32 ` Tejun Heo
2012-09-26 17:20 ` [PATCH 05/12] workqueue: don't wake up other workers in rescuer Lai Jiangshan
2012-09-26 18:34 ` Tejun Heo
2012-09-28 10:18 ` Lai Jiangshan
2012-09-26 17:20 ` [PATCH 06/12] workqueue: destroy_worker() can only destory idle worker not just created worker Lai Jiangshan
2012-09-26 18:35 ` Tejun Heo
2012-09-26 17:20 ` [PATCH 07/12] workqueue: remove WORKER_STARTED Lai Jiangshan
2012-09-26 18:36 ` Tejun Heo
2012-09-28 9:52 ` Lai Jiangshan
2012-09-26 17:20 ` [PATCH 08/12] workqueue: fix comments of insert_work() Lai Jiangshan
2012-09-26 17:20 ` [PATCH 09/12] workqueue: declare system_highpri_wq Lai Jiangshan
2012-09-26 17:20 ` [PATCH 10/12] cpu-hotplug.txt: fix comments of work_on_cpu() Lai Jiangshan
2012-09-26 17:20 ` [RFC PATCH 11/12] workqueue: add WQ_CPU_INTENSIVE to system_long_wq Lai Jiangshan
2012-09-26 18:38 ` Tejun Heo
2012-09-28 8:06 ` Lai Jiangshan
2012-09-30 7:22 ` Tejun Heo
2012-09-26 17:20 ` [PATCH 12/12] workqueue: avoid work_on_cpu() to interfere system_wq Lai Jiangshan
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