Messages in this thread | | | Date | Wed, 15 Apr 2009 12:22:57 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH v2 2/4] ftrace: introduce workqueue_handler_exit tracepoint and rename workqueue_execution to workqueue_handler_entry |
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I am very sorry for delay. I am going to study these patches later.
Just one note,
> On Mon, Apr 13, 2009 at 02:53:01PM +0900, KOSAKI Motohiro wrote: > > > Subject: [PATCH] ftrace: introduce workqueue_handler_exit tracepoint and rename workqueue_execution to workqueue_handler_entry > > > > Entry/exit handler pair is useful common tracepoint technique. it can mesure handler consumption time. ... > > static void run_workqueue(struct cpu_workqueue_struct *cwq) > > { > > @@ -282,7 +283,6 @@ static void run_workqueue(struct cpu_wor > > */ > > struct lockdep_map lockdep_map = work->lockdep_map; > > #endif > > - trace_workqueue_execution(cwq->thread, work); > > cwq->current_work = work; > > list_del_init(cwq->worklist.next); > > spin_unlock_irq(&cwq->lock); > > @@ -291,7 +291,9 @@ static void run_workqueue(struct cpu_wor > > work_clear_pending(work); > > lock_map_acquire(&cwq->wq->lockdep_map); > > lock_map_acquire(&lockdep_map); > > + trace_workqueue_handler_entry(cwq->thread, work); > > f(work); > > + trace_workqueue_handler_exit(cwq->thread, work);
This doesn't look right. We must not use "work" after f(work). work->func() can kfree its work.
That is why we copy lockdep_map beforehand. Perhaps ftrace should do something similar.
Oleg.
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