return n * sizeof(u64);
}
+static bool is_event_hup(struct perf_event *event)
+{
+ bool no_children;
+
+ if (event->state != PERF_EVENT_STATE_EXIT)
+ return false;
+
+ mutex_lock(&event->child_mutex);
+ no_children = list_empty(&event->child_list);
+ mutex_unlock(&event->child_mutex);
+ return no_children;
+}
+
/*
* Read the performance event - simple non blocking version for now
*/
poll_wait(file, &event->waitq, wait);
- if (event->state == PERF_EVENT_STATE_EXIT)
+ if (is_event_hup(event))
return events;
/*
mutex_unlock(&parent_event->child_mutex);
/*
+ * Make sure user/parent get notified, that we just
+ * lost one event.
+ */
+ perf_event_wakeup(parent_event);
+
+ /*
* Release the parent event, if this was the last
* reference to it.
*/