Messages in this thread |  | | Date | Tue, 05 Feb 2013 20:15:18 +0800 | From | Lai Jiangshan <> | Subject | Re: [PATCH 08/13] workqueue: add lock_pool_executing_work() |
| |
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.
-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |