On Thu, Sep 27, 2012 at 01:20:35AM +0800, Lai Jiangshan wrote:
> is_chained_work() is too complicated. we can simply found out
> whether current task is worker by PF_WQ_WORKER or wq->rescuer.
>
> Signed-off-by: Lai Jiangshan <la...@cn.fujitsu.com>
> ---
> kernel/workqueue.c | 36 ++++++++++++------------------------
> 1 files changed, 12 insertions(+), 24 deletions(-)
>
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index e41c562..c718b94 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -1182,34 +1182,22 @@ static void insert_work(struct cpu_workqueue_struct
> *cwq,
>
> /*
> * Test whether @work is being queued from another work executing on the
> - * same workqueue. This is rather expensive and should only be used from
> - * cold paths.
> + * same workqueue.
> */
> static bool is_chained_work(struct workqueue_struct *wq)
> {
> - unsigned long flags;
> - unsigned int cpu;
> + struct worker *worker = NULL;
>
> - for_each_gcwq_cpu(cpu) {
> - struct global_cwq *gcwq = get_gcwq(cpu);
> - struct worker *worker;
> - struct hlist_node *pos;
> - int i;
> + if (wq->rescuer && current == wq->rescuer->task) /* rescuer_thread() */
> + worker = wq->rescuer;
> + else if (current->flags & PF_WQ_WORKER) /* worker_thread() */
> + worker = kthread_data(current);
>
> - spin_lock_irqsave(&gcwq->lock, flags);
> - for_each_busy_worker(worker, i, pos, gcwq) {
> - if (worker->task != current)
> - continue;
> - spin_unlock_irqrestore(&gcwq->lock, flags);
> - /*
> - * I'm @worker, no locking necessary. See if @work
> - * is headed to the same workqueue.
> - */
> - return worker->current_cwq->wq == wq;
> - }
> - spin_unlock_irqrestore(&gcwq->lock, flags);
> - }
> - return false;
> + /*
> + * I'm @worker, no locking necessary. See if @work
> + * is headed to the same workqueue.
> + */
> + return worker && worker->current_cwq->wq == wq;
How about,
if (wq->rescuer && current == wq->rescuer->task)
worker = wq->rescuer;
else if (current->flags & PF_WQ_WORKER)
worker = kthread_data(current);
else
return NULL;
return worker->curent_cwq->wq == wq;
Thanks.
--
tejun
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