From: Tejun Heo <tj@kernel.org>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
Lai Jiangshan <jiangshanlai@gmail.com>,
"Paul E . McKenney" <paulmck@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <frederic@kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH v2] workqueue: doc: Call out the non-reentrance conditions
Date: Mon, 25 Oct 2021 07:20:23 -1000 [thread overview]
Message-ID: <YXbnV8wbrL5LEZZP@slm.duckdns.org> (raw)
In-Reply-To: <20211022004208.350992-1-boqun.feng@gmail.com>
On Fri, Oct 22, 2021 at 08:42:08AM +0800, Boqun Feng wrote:
> The current doc of workqueue API suggests that work items are
> non-reentrant: any work item is guaranteed to be executed by at most one
> worker system-wide at any given time. However this is not true, the
> following case can cause a work item W executed by two workers at
> the same time:
>
> queue_work_on(0, WQ1, W);
> // after a worker picks up W and clear the pending bit
> queue_work_on(1, WQ2, W);
> // workers on CPU0 and CPU1 will execute W in the same time.
>
> , which means the non-reentrance of a work item is conditional, and
> Lai Jiangshan provided a nice summary[1] of the conditions, therefore
> use it to describe a work item instance and improve the doc.
>
> [1]: https://lore.kernel.org/lkml/CAJhGHyDudet_xyNk=8xnuO2==o-u06s0E0GZVP4Q67nmQ84Ceg@mail.gmail.com/
>
> Suggested-by: Matthew Wilcox <willy@infradead.org>
> Suggested-by: Tejun Heo <tj@kernel.org>
> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Applied to wq/for-5.16.
Thanks.
--
tejun
prev parent reply other threads:[~2021-10-25 17:20 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-22 0:42 Boqun Feng
2021-10-25 17:20 ` Tejun Heo [this message]
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