Hey, On Wed, Mar 20, 2013 at 11:01:50PM +0900, JoonSoo Kim wrote: > 2013/3/19 Tejun Heo <[email protected]>: > > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
