workqueue: add worker function to workqueue_execute_end tracepoint

It's surprising that workqueue_execute_end includes only the work when
its counterpart workqueue_execute_start has both the work and the worker
function.

You can't set a tracing filter or trigger based on the function, and
postprocessing scripts interested in specific functions are harder to
write since they have to remember the work from _start and match it up
with the same field in _end.

Add the function name, taking care to use the copy stashed in the
worker since the work is no longer safe to touch.

Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/include/trace/events/workqueue.h b/include/trace/events/workqueue.h
index e172549283beaa1ed24d02871032b945ef8f800d..bdfc53e7f82f8469155ca7a31fb50e27f093bdcd 100644 (file)
--- a/include/trace/events/workqueue.h
+++ b/include/trace/events/workqueue.h
@@ -108,14 +108,27 @@ TRACE_EVENT(workqueue_execute_start,
 /**
  * workqueue_execute_end - called immediately after the workqueue callback
  * @work:      pointer to struct work_struct
+ * @function:   pointer to worker function
  *
  * Allows to track workqueue execution.
  */
-DEFINE_EVENT(workqueue_work, workqueue_execute_end,
+TRACE_EVENT(workqueue_execute_end,
 
-       TP_PROTO(struct work_struct *work),
+       TP_PROTO(struct work_struct *work, work_func_t function),
 
-       TP_ARGS(work)
+       TP_ARGS(work, function),
+
+       TP_STRUCT__entry(
+               __field( void *,        work    )
+               __field( void *,        function)
+       ),
+
+       TP_fast_assign(
+               __entry->work           = work;
+               __entry->function       = function;
+       ),
+
+       TP_printk("work struct %p: function %ps", __entry->work, __entry->function)
 );
 
 #endif /*  _TRACE_WORKQUEUE_H */

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index cfc923558e04de32f603525343d9548128ca25cd..4bdfa270a37bf7c82f8aa20533efd2b4c24afd1c 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2266,7 +2266,7 @@ __acquires(&pool->lock)
         * While we must be careful to not use "work" after this, the trace
         * point will only record its address.
         */
-       trace_workqueue_execute_end(work);
+       trace_workqueue_execute_end(work, worker->current_func);
        lock_map_release(&lockdep_map);
        lock_map_release(&pwq->wq->lockdep_map);