From: Tejun Heo <tj@kernel.org>
To: JoonSoo Kim <js1304@gmail.com>
Cc: linux-kernel@vger.kernel.org, laijs@cn.fujitsu.com
Subject: Re: [PATCHSET wq/for-3.10] workqueue: break up workqueue_lock into multiple locks
Date: Wed, 20 Mar 2013 07:38:32 -0700 [thread overview]
Message-ID: <20130320143832.GT3042@htj.dyndns.org> (raw)
In-Reply-To: <CAAmzW4N=t=aB194E-B185x1gqTJqNK4XO_diiaJrhjx+CN-_VA@mail.gmail.com>
Hey,
On Wed, Mar 20, 2013 at 11:01:50PM +0900, JoonSoo Kim wrote:
> 2013/3/19 Tejun Heo <tj@kernel.org>:
> > On Wed, Mar 13, 2013 at 07:57:18PM -0700, Tejun Heo wrote:
> >> and available in the following git branch.
> >>
> >> git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git review-finer-locking
> >
> > Applied to wq/for-3.10.
>
> Hello, Tejun.
>
> I know I am late, but, please give me a change to ask a question.
>
> Finer locking for workqueue code is really needed?
> Is there a performance issue?
> I think that there is too many locks and locking rules,
> although the description about these are very nice.
It isn't about performance. So, workqueue_lock is broken into three
locks by this series - wq_mutex, pwq_lock and mayday_lock. The
primary reason for this patchset is wq_mutex. We want to do blocking
operations while excluding workqueue and pool modifications which
isn't possible with workqueue_lock and at the same time there are
things which can't be protected by a mutex (should be a irq-safe
lock), so we need break up the lock. After breaking off wq_mutex from
workqueue_lock. Most stuff covered by workqueue_lock was pwq related
and mayday was the only one-off thing left, so one more lock there,
which I think actually make things easier to digest.
Thanks.
--
tejun
prev parent reply other threads:[~2013-03-20 14:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-14 2:57 [PATCHSET wq/for-3.10] workqueue: break up workqueue_lock into multiple locks Tejun Heo
2013-03-14 2:57 ` [PATCH 1/7] workqueue: rename worker_pool->assoc_mutex to ->manager_mutex Tejun Heo
2013-03-14 16:00 ` Lai Jiangshan
2013-03-14 16:41 ` Tejun Heo
2013-03-14 2:57 ` [PATCH 2/7] workqueue: factor out initial worker creation into create_and_start_worker() Tejun Heo
2013-03-14 2:57 ` [PATCH 3/7] workqueue: better define locking rules around worker creation / destruction Tejun Heo
2013-03-14 2:57 ` [PATCH 4/7] workqueue: relocate global variable defs and function decls in workqueue.c Tejun Heo
2013-03-14 2:57 ` [PATCH 5/7] workqueue: separate out pool and workqueue locking into wq_mutex Tejun Heo
2013-03-14 2:57 ` [PATCH 6/7] workqueue: separate out pool_workqueue locking into pwq_lock Tejun Heo
2013-03-14 2:57 ` [PATCH 7/7] workqueue: rename workqueue_lock to wq_mayday_lock Tejun Heo
2013-03-18 19:51 ` [PATCHSET wq/for-3.10] workqueue: break up workqueue_lock into multiple locks Tejun Heo
2013-03-20 14:01 ` JoonSoo Kim
2013-03-20 14:38 ` Tejun Heo [this message]
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