Messages in this thread Patch in this message | | | From | Lai Jiangshan <> | Subject | [PATCH 04/12] workqueue: simplify is_chained_work() | Date | Thu, 27 Sep 2012 01:20:35 +0800 |
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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 <laijs@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; } static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, @@ -1231,7 +1219,7 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, debug_work_activate(work); - /* if dying, only works from the same workqueue are allowed */ + /* if draining, only works from the same workqueue are allowed */ if (unlikely(wq->flags & WQ_DRAINING) && WARN_ON_ONCE(!is_chained_work(wq))) return; -- 1.7.7.6
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