---

yaml
---
r: 217457
b: refs/heads/master
c: 52bb919
h: refs/heads/master
i:
  217455: a5b8ae7
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e11da5b4fdf01d71d73c21cb92b00595b917d7fd
+refs/heads/master: 52bb9198668968506f9d12bf35d7f5d3f094921e

trunk/include/trace/events/writeback.h

@@ -151,6 +151,34 @@ DEFINE_WBC_EVENT(wbc_balance_dirty_written);
 DEFINE_WBC_EVENT(wbc_balance_dirty_wait);
 DEFINE_WBC_EVENT(wbc_writepage);
 
+DECLARE_EVENT_CLASS(writeback_congest_waited_template,
+
+	TP_PROTO(unsigned int usec_timeout, unsigned int usec_delayed),
+
+	TP_ARGS(usec_timeout, usec_delayed),
+
+	TP_STRUCT__entry(
+		__field(	unsigned int,	usec_timeout	)
+		__field(	unsigned int,	usec_delayed	)
+	),
+
+	TP_fast_assign(
+		__entry->usec_timeout	= usec_timeout;
+		__entry->usec_delayed	= usec_delayed;
+	),
+
+	TP_printk("usec_timeout=%u usec_delayed=%u",
+			__entry->usec_timeout,
+			__entry->usec_delayed)
+);
+
+DEFINE_EVENT(writeback_congest_waited_template, writeback_congestion_wait,
+
+	TP_PROTO(unsigned int usec_timeout, unsigned int usec_delayed),
+
+	TP_ARGS(usec_timeout, usec_delayed)
+);
+
 #endif /* _TRACE_WRITEBACK_H */
 
 /* This part must be outside protection */

trunk/mm/backing-dev.c

@@ -764,12 +764,17 @@ EXPORT_SYMBOL(set_bdi_congested);
 long congestion_wait(int sync, long timeout)
 {
 	long ret;
+	unsigned long start = jiffies;
 	DEFINE_WAIT(wait);
 	wait_queue_head_t *wqh = &congestion_wqh[sync];
 
 	prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE);
 	ret = io_schedule_timeout(timeout);
 	finish_wait(wqh, &wait);
+
+	trace_writeback_congestion_wait(jiffies_to_usecs(timeout),
+					jiffies_to_usecs(jiffies - start));
+
 	return ret;
 }
 EXPORT_SYMBOL(congestion_wait);