Add a tracepoint for block request remapping

Since 2.6.31 now has request-based device-mapper, it's useful to have a tracepoint for request-remapping as well as bio-remapping. This patch adds a tracepoint for request-remapping, trace_block_rq_remap(). Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Alasdair G Kergon <agk@redhat.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Add a tracepoint for block request remapping
Since 2.6.31 now has request-based device-mapper, it's useful to have a tracepoint for request-remapping as well as bio-remapping. This patch adds a tracepoint for request-remapping, trace_block_rq_remap(). Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Alasdair G Kergon <agk@redhat.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Jun'ichi Nomura · Jens Axboe
1 parent 67efc92580
Showing 4 changed files with 69 additions and 1 deletions Side-by-side Diff
block/blk-core.c
include/linux/blktrace_api.h
include/trace/events/block.h
kernel/trace/blktrace.c
@@ -34,6 +34,7 @@
 #include "blk.h"
  
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_remap);
+EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
  
 static int __make_request(struct request_queue *q, struct bio *bio);
@@ -212,7 +212,7 @@
 # define blk_trace_startstop(q, start)			(-ENOTTY)
 # define blk_trace_remove(q)				(-ENOTTY)
 # define blk_add_trace_msg(q, fmt, ...)			do { } while (0)
-# define blk_trace_remove_sysfs(struct device *dev)	do { } while (0)
+# define blk_trace_remove_sysfs(dev)			do { } while (0)
 static inline int blk_trace_init_sysfs(struct device *dev)
 {
 	return 0;
@@ -488,6 +488,39 @@
 		  (unsigned long long)__entry->old_sector)
 );
  
+TRACE_EVENT(block_rq_remap,
+
+	TP_PROTO(struct request_queue *q, struct request *rq, dev_t dev,
+		 sector_t from),
+
+	TP_ARGS(q, rq, dev, from),
+
+	TP_STRUCT__entry(
+		__field( dev_t,		dev		)
+		__field( sector_t,	sector		)
+		__field( unsigned int,	nr_sector	)
+		__field( dev_t,		old_dev		)
+		__field( sector_t,	old_sector	)
+		__array( char,		rwbs,	6	)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= disk_devt(rq->rq_disk);
+		__entry->sector		= blk_rq_pos(rq);
+		__entry->nr_sector	= blk_rq_sectors(rq);
+		__entry->old_dev	= dev;
+		__entry->old_sector	= from;
+		blk_fill_rwbs_rq(__entry->rwbs, rq);
+	),
+
+	TP_printk("%d,%d %s %llu + %u <- (%d,%d) %llu",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
+		  (unsigned long long)__entry->sector,
+		  __entry->nr_sector,
+		  MAJOR(__entry->old_dev), MINOR(__entry->old_dev),
+		  (unsigned long long)__entry->old_sector)
+);
+
 #endif /* _TRACE_BLOCK_H */
  
 /* This part must be outside protection */
@@ -856,6 +856,37 @@
 }
  
 /**
+ * blk_add_trace_rq_remap - Add a trace for a request-remap operation
+ * @q:		queue the io is for
+ * @rq:		the source request
+ * @dev:	target device
+ * @from:	source sector
+ *
+ * Description:
+ *     Device mapper remaps request to other devices.
+ *     Add a trace for that action.
+ *
+ **/
+static void blk_add_trace_rq_remap(struct request_queue *q,
+				   struct request *rq, dev_t dev,
+				   sector_t from)
+{
+	struct blk_trace *bt = q->blk_trace;
+	struct blk_io_trace_remap r;
+
+	if (likely(!bt))
+		return;
+
+	r.device_from = cpu_to_be32(dev);
+	r.device_to   = cpu_to_be32(disk_devt(rq->rq_disk));
+	r.sector_from = cpu_to_be64(from);
+
+	__blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
+			rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
+			sizeof(r), &r);
+}
+
+/**
  * blk_add_driver_data - Add binary message with driver-specific data
  * @q:		queue the io is for
  * @rq:		io request
  
@@ -922,10 +953,13 @@
 	WARN_ON(ret);
 	ret = register_trace_block_remap(blk_add_trace_remap);
 	WARN_ON(ret);
+	ret = register_trace_block_rq_remap(blk_add_trace_rq_remap);
+	WARN_ON(ret);
 }
  
 static void blk_unregister_tracepoints(void)
 {
+	unregister_trace_block_rq_remap(blk_add_trace_rq_remap);
 	unregister_trace_block_remap(blk_add_trace_remap);
 	unregister_trace_block_split(blk_add_trace_split);
 	unregister_trace_block_unplug_io(blk_add_trace_unplug_io);
...	...	@@ -34,6 +34,7 @@
34	34	#include "blk.h"
35	35
36	36	EXPORT_TRACEPOINT_SYMBOL_GPL(block_remap);
	37	+EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
37	38	EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
38	39
39	40	static int __make_request(struct request_queue q, struct bio bio);
...	...	@@ -212,7 +212,7 @@
212	212	# define blk_trace_startstop(q, start) (-ENOTTY)
213	213	# define blk_trace_remove(q) (-ENOTTY)
214	214	# define blk_add_trace_msg(q, fmt, ...) do { } while (0)
215		-# define blk_trace_remove_sysfs(struct device *dev) do { } while (0)
	215	+# define blk_trace_remove_sysfs(dev) do { } while (0)
216	216	static inline int blk_trace_init_sysfs(struct device *dev)
217	217	{
218	218	return 0;
...	...	@@ -488,6 +488,39 @@
488	488	(unsigned long long)__entry->old_sector)
489	489	);
490	490
	491	+TRACE_EVENT(block_rq_remap,
	492	+
	493	+ TP_PROTO(struct request_queue q, struct request rq, dev_t dev,
	494	+ sector_t from),
	495	+
	496	+ TP_ARGS(q, rq, dev, from),
	497	+
	498	+ TP_STRUCT__entry(
	499	+ __field( dev_t, dev )
	500	+ __field( sector_t, sector )
	501	+ __field( unsigned int, nr_sector )
	502	+ __field( dev_t, old_dev )
	503	+ __field( sector_t, old_sector )
	504	+ __array( char, rwbs, 6 )
	505	+ ),
	506	+
	507	+ TP_fast_assign(
	508	+ __entry->dev = disk_devt(rq->rq_disk);
	509	+ __entry->sector = blk_rq_pos(rq);
	510	+ __entry->nr_sector = blk_rq_sectors(rq);
	511	+ __entry->old_dev = dev;
	512	+ __entry->old_sector = from;
	513	+ blk_fill_rwbs_rq(__entry->rwbs, rq);
	514	+ ),
	515	+
	516	+ TP_printk("%d,%d %s %llu + %u <- (%d,%d) %llu",
	517	+ MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
	518	+ (unsigned long long)__entry->sector,
	519	+ __entry->nr_sector,
	520	+ MAJOR(__entry->old_dev), MINOR(__entry->old_dev),
	521	+ (unsigned long long)__entry->old_sector)
	522	+);
	523	+
491	524	#endif /* _TRACE_BLOCK_H */
492	525
493	526	/* This part must be outside protection */
...	...	@@ -856,6 +856,37 @@
856	856	}
857	857
858	858	/**
	859	+ * blk_add_trace_rq_remap - Add a trace for a request-remap operation
	860	+ * @q: queue the io is for
	861	+ * @rq: the source request
	862	+ * @dev: target device
	863	+ * @from: source sector
	864	+ *
	865	+ * Description:
	866	+ * Device mapper remaps request to other devices.
	867	+ * Add a trace for that action.
	868	+ *
	869	+ **/
	870	+static void blk_add_trace_rq_remap(struct request_queue *q,
	871	+ struct request *rq, dev_t dev,
	872	+ sector_t from)
	873	+{
	874	+ struct blk_trace *bt = q->blk_trace;
	875	+ struct blk_io_trace_remap r;
	876	+
	877	+ if (likely(!bt))
	878	+ return;
	879	+
	880	+ r.device_from = cpu_to_be32(dev);
	881	+ r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
	882	+ r.sector_from = cpu_to_be64(from);
	883	+
	884	+ __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
	885	+ rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
	886	+ sizeof(r), &r);
	887	+}
	888	+
	889	+/**
859	890	* blk_add_driver_data - Add binary message with driver-specific data
860	891	* @q: queue the io is for
861	892	* @rq: io request
862	893
...	...	@@ -922,10 +953,13 @@
922	953	WARN_ON(ret);
923	954	ret = register_trace_block_remap(blk_add_trace_remap);
924	955	WARN_ON(ret);
	956	+ ret = register_trace_block_rq_remap(blk_add_trace_rq_remap);
	957	+ WARN_ON(ret);
925	958	}
926	959
927	960	static void blk_unregister_tracepoints(void)
928	961	{
	962	+ unregister_trace_block_rq_remap(blk_add_trace_rq_remap);
929	963	unregister_trace_block_remap(blk_add_trace_remap);
930	964	unregister_trace_block_split(blk_add_trace_split);
931	965	unregister_trace_block_unplug_io(blk_add_trace_unplug_io);