From: "Kim, Milo" <Milo.Kim@ti.com>
To: Bryan Wu <bryan.wu@canonical.com>
Cc: Tejun Heo <tj@kernel.org>, Richard Purdie <rpurdie@rpsys.net>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-leds@vger.kernel.org" <linux-leds@vger.kernel.org>
Subject: RE: [PATCH 2/4] leds-lp5523: set the brightness to 0 forcely on removing the driver
Date: Wed, 22 Aug 2012 05:46:21 +0000 [thread overview]
Message-ID: <A874F61F95741C4A9BA573A70FE3998F41EF0BFF@DQHE02.ent.ti.com> (raw)
In-Reply-To: <CAK5ve-LoER0X36JMBjY4Dqgts5FapAs=2w01J05YgJ8tmYHMkg@mail.gmail.com>
> Hmmm, I think we still should use cancel_work() here based on your
> idea. Please find the patch from Tejun and add him to this loop
> [PATCH 4/6] workqueue: deprecate flush[_delayed]_work_sync()
> ---
> Before this patchset,
>
> flush_work()
>
> flush the last queued instance of the work item. If it got
> queued on multple CPUs, it only considers the last queued
> instance. The work item could still be executing on other
> CPUs and the flush might become noop if there are competing
> queueing operation on another CPU.
>
> flush_work_sync()
>
> flush_work() + wait for executing instances on all CPUs. The
> flush_work() part may still become noop if there's competing
> queueing operation.
>
> cancel_work()
>
> Dequeue the work item if it's pending. Doesn't care about
> whether it's executing or not.
>
> cancel_work_sync()
>
> cancel_work() + flush_work_sync().
>
>
> After this patchset,
>
> flush_work()
>
> flush the work item. Any queueing happened previously is
> guaranteed to have finished execution on return. If no
> further queueing happened after flush started, the work item
> is guaranteed to be idle on return.
>
> cancel_work()
>
> Same as before.
>
> cancel_work_sync()
>
> cancel_work() followed by flush_work(). The same semantics as
> del_timer_sync().
> ---
>
> cancel_work_sync() won't execute the work item at all just cancel
> them, but flush will execute them and return.
>
Thanks a lot for the updates!
Then, I think flush_work() should be used for executing remaining brightness work
rather than cancel_work_sync().
Best Regards,
Milo
next prev parent reply other threads:[~2012-08-22 5:47 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-21 9:03 [PATCH 2/4] leds-lp5523: set the brightness to 0 forcely on removing the driver Kim, Milo
2012-08-22 3:37 ` Bryan Wu
2012-08-22 5:46 ` Kim, Milo [this message]
2012-08-22 7:22 ` Bryan Wu
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