From: Lai Jiangshan <eag0628@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 08/13] workqueue: add lock_pool_executing_work()
Date: Tue, 05 Feb 2013 20:15:18 +0800 [thread overview]
Message-ID: <5110F7D6.8080203@gmail.com> (raw)
In-Reply-To: <20130204213422.GD27963@mtj.dyndns.org>
于 2013/2/5 5:34, Tejun Heo 写道:
> Hello,
>
> On Fri, Feb 01, 2013 at 02:41:31AM +0800, Lai Jiangshan wrote:
>> +static struct worker_pool *lock_pool_executing_work(struct work_struct *work,
>> + struct worker **worker)
>> +{
>> + unsigned long pool_id = offq_work_pool_id(work);
>> + struct worker_pool *pool;
>> + struct worker *exec;
>> +
>> + if (pool_id == WORK_OFFQ_POOL_NONE)
>> + return NULL;
>> +
>> + pool = worker_pool_by_id(pool_id);
>> + if (!pool)
>> + return NULL;
>> +
>> + spin_lock(&pool->lock);
>> + exec = find_worker_executing_work(pool, work);
>> + if (exec) {
>> + BUG_ON(pool != exec->pool);
>> + *worker = exec;
>> + return pool;
>> + }
>> + spin_unlock(&pool->lock);
>> +
>> + return NULL;
>> +}
>
> So, if a work item is queued on the same CPU and it isn't being
> executed, it will lock, look up the hash, unlock and then lock again?
> If this is something improved by later patch, please explain so.
> There gotta be a better way to do this, right?
>
The caller can't call this function if the work is on queue.
the caller should call it only when CWQ bit is not set.
it is commentted "lock the pool a given offq work is running on",
sorry, comment is too short.
next prev parent reply other threads:[~2013-02-05 12:15 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-31 18:41 [PATCH 00/13] workqueue: enhance locking and record global worker id for work data Lai Jiangshan
2013-01-31 18:41 ` [PATCH 01/13] workqueue: remove WORK_CPU_NONE Lai Jiangshan
2013-02-04 19:49 ` Tejun Heo
2013-02-05 12:03 ` Lai Jiangshan
2013-02-06 22:34 ` [PATCH wq/for-3.9] workqueue: replace WORK_CPU_NONE/LAST with WORK_CPU_END Tejun Heo
2013-01-31 18:41 ` [PATCH 02/13] workqueue: fix work_busy() Lai Jiangshan
2013-02-04 19:54 ` Tejun Heo
2013-02-05 12:06 ` Lai Jiangshan
2013-02-05 18:53 ` Tejun Heo
2013-02-06 11:42 ` Lai Jiangshan
2013-02-06 14:05 ` Tejun Heo
2013-02-06 23:02 ` [PATCH wq/for-3.9] workqueue: make work_busy() test WORK_STRUCT_PENDING first Tejun Heo
2013-01-31 18:41 ` [PATCH 03/13] workqueue: don't set work cwq until we queued it on pool Lai Jiangshan
2013-02-04 21:28 ` Tejun Heo
2013-02-05 15:00 ` Lai Jiangshan
2013-02-05 16:45 ` Tejun Heo
2013-02-06 11:35 ` Lai Jiangshan
2013-02-06 14:18 ` Tejun Heo
2013-02-05 15:06 ` Lai Jiangshan
2013-02-07 0:28 ` [PATCH wq/for-3.9 workqueue]: add delayed_work->wq to simplify reentrancy handling Tejun Heo
2013-01-31 18:41 ` [PATCH 04/13] workqueue: clear cwq when cancel the work Lai Jiangshan
2013-02-07 0:53 ` [PATCH wq/for-3.9] workqueue: make work->data point to pool after try_to_grab_pending() Tejun Heo
2013-01-31 18:41 ` [PATCH 05/13] workqueue: change queued detection and remove *mb()s Lai Jiangshan
2013-02-07 1:52 ` [PATCH wq/for-3.9] workqueue: simplify is-work-item-queued-here test Tejun Heo
2013-02-07 2:03 ` [PATCH wq/for-3.9] workqueue: cosmetic update in try_to_grab_pending() Tejun Heo
2013-01-31 18:41 ` [PATCH 06/13] workqueue: get pool id from work->data directly if it is offq Lai Jiangshan
2013-02-07 20:16 ` [PATCH wq/for-3.9] workqueue: make get_work_pool_id() cheaper Tejun Heo
2013-01-31 18:41 ` [PATCH 07/13] workqueue: get pool from wq/cwq Lai Jiangshan
2013-02-07 21:13 ` [PATCH wq/for-3.9] workqueue: pick cwq instead of pool in __queue_work() Tejun Heo
2013-01-31 18:41 ` [PATCH 08/13] workqueue: add lock_pool_executing_work() Lai Jiangshan
2013-02-04 21:34 ` Tejun Heo
2013-02-05 12:15 ` Lai Jiangshan [this message]
2013-02-05 19:09 ` Tejun Heo
2013-01-31 18:41 ` [PATCH 09/13] workqueue: add lock_pool_queued_work() Lai Jiangshan
2013-01-31 18:41 ` [PATCH 10/13] workqueue: add lock_pool_own_work() and remove get_work_pool() Lai Jiangshan
2013-02-04 21:38 ` Tejun Heo
2013-01-31 18:41 ` [PATCH 11/13] workqueue: allow more work_pool id space Lai Jiangshan
2013-01-31 18:41 ` [PATCH 12/13] workqueue: add worker's global worker ID Lai Jiangshan
2013-02-04 21:39 ` Tejun Heo
2013-01-31 18:41 ` [PATCH 13/13] workqueue: record global worker ID instead of pool ID in work->data when off-queue Lai Jiangshan
2013-02-04 21:40 ` Tejun Heo
2013-02-04 22:12 ` Tejun Heo
2013-02-05 15:18 ` Lai Jiangshan
2013-02-07 22:02 ` Tejun Heo
2013-02-13 22:23 ` Tejun Heo
2013-02-04 21:04 ` [PATCH 00/13] workqueue: enhance locking and record global worker id for work data Tejun Heo
2013-02-05 16:19 ` Lai Jiangshan
2013-02-05 16:50 ` Tejun Heo
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