tracing/events: convert block trace points to TRACE_EVENT()

TRACE_EVENT is a more generic way to define tracepoints. Doing so adds
these new capabilities to this tracepoint:

  - zero-copy and per-cpu splice() tracing
  - binary tracing without printf overhead
  - structured logging records exposed under /debug/tracing/events
  - trace events embedded in function tracer output and other plugins
  - user-defined, per tracepoint filter expressions
  ...

Cons:

  - no dev_t info for the output of plug, unplug_timer and unplug_io events.
    no dev_t info for getrq and sleeprq events if bio == NULL.
    no dev_t info for rq_abort,...,rq_requeue events if rq->rq_disk == NULL.

    This is mainly because we can't get the deivce from a request queue.
    But this may change in the future.

  - A packet command is converted to a string in TP_assign, not TP_print.
    While blktrace do the convertion just before output.

    Since pc requests should be rather rare, this is not a big issue.

  - In blktrace, an event can have 2 different print formats, but a TRACE_EVENT
    has a unique format, which means we have some unused data in a trace entry.

    The overhead is minimized by using __dynamic_array() instead of __array().

I've benchmarked the ioctl blktrace vs the splice based TRACE_EVENT tracing:

      dd                   dd + ioctl blktrace       dd + TRACE_EVENT (splice)
1     7.36s, 42.7 MB/s     7.50s, 42.0 MB/s          7.41s, 42.5 MB/s
2     7.43s, 42.3 MB/s     7.48s, 42.1 MB/s          7.43s, 42.4 MB/s
3     7.38s, 42.6 MB/s     7.45s, 42.2 MB/s          7.41s, 42.5 MB/s

So the overhead of tracing is very small, and no regression when using
those trace events vs blktrace.

And the binary output of TRACE_EVENT is much smaller than blktrace:

 # ls -l -h
 -rw-r--r-- 1 root root 8.8M 06-09 13:24 sda.blktrace.0
 -rw-r--r-- 1 root root 195K 06-09 13:24 sda.blktrace.1
 -rw-r--r-- 1 root root 2.7M 06-09 13:25 trace_splice.out

Following are some comparisons between TRACE_EVENT and blktrace:

plug:
  kjournald-480   [000]   303.084981: block_plug: [kjournald]
  kjournald-480   [000]   303.084981:   8,0    P   N [kjournald]

unplug_io:
  kblockd/0-118   [000]   300.052973: block_unplug_io: [kblockd/0] 1
  kblockd/0-118   [000]   300.052974:   8,0    U   N [kblockd/0] 1

remap:
  kjournald-480   [000]   303.085042: block_remap: 8,0 W 102736992 + 8 <- (8,8) 33384
  kjournald-480   [000]   303.085043:   8,0    A   W 102736992 + 8 <- (8,8) 33384

bio_backmerge:
  kjournald-480   [000]   303.085086: block_bio_backmerge: 8,0 W 102737032 + 8 [kjournald]
  kjournald-480   [000]   303.085086:   8,0    M   W 102737032 + 8 [kjournald]

getrq:
  kjournald-480   [000]   303.084974: block_getrq: 8,0 W 102736984 + 8 [kjournald]
  kjournald-480   [000]   303.084975:   8,0    G   W 102736984 + 8 [kjournald]

  bash-2066  [001]  1072.953770:   8,0    G   N [bash]
  bash-2066  [001]  1072.953773: block_getrq: 0,0 N 0 + 0 [bash]

rq_complete:
  konsole-2065  [001]   300.053184: block_rq_complete: 8,0 W () 103669040 + 16 [0]
  konsole-2065  [001]   300.053191:   8,0    C   W 103669040 + 16 [0]

  ksoftirqd/1-7   [001]  1072.953811:   8,0    C   N (5a 00 08 00 00 00 00 00 24 00) [0]
  ksoftirqd/1-7   [001]  1072.953813: block_rq_complete: 0,0 N (5a 00 08 00 00 00 00 00 24 00) 0 + 0 [0]

rq_insert:
  kjournald-480   [000]   303.084985: block_rq_insert: 8,0 W 0 () 102736984 + 8 [kjournald]
  kjournald-480   [000]   303.084986:   8,0    I   W 102736984 + 8 [kjournald]

Changelog from v2 -> v3:

- use the newly introduced __dynamic_array().

Changelog from v1 -> v2:

- use __string() instead of __array() to minimize the memory required
  to store hex dump of rq->cmd().

- support large pc requests.

- add missing blk_fill_rwbs_rq() in block_rq_requeue TRACE_EVENT.

- some cleanups.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A2DF669.5070905@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 483 insertions, 0 deletions

diff --git a/include/trace/events/block.h b/include/trace/events/block.h
new file mode 100644
index 00000000000..a99d1e565bb
--- /dev/null
+++ b/include/trace/events/block.h
@@ -0,0 +1,483 @@
+#if !defined(_TRACE_BLOCK_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_BLOCK_H
+
+#include <linux/blktrace_api.h>
+#include <linux/blkdev.h>
+#include <linux/tracepoint.h>
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM block
+
+TRACE_EVENT(block_rq_abort,
+
+	TP_PROTO(struct request_queue *q, struct request *rq),
+
+	TP_ARGS(q, rq),
+
+	TP_STRUCT__entry(
+		__field(  dev_t,	dev			)
+		__field(  sector_t,	sector			)
+		__field(  unsigned int,	nr_sector		)
+		__field(  int,		errors			)
+		__array(  char,		rwbs,	6		)
+		__dynamic_array( char,	cmd,	blk_cmd_buf_len(rq)	)
+	),
+
+	TP_fast_assign(
+		__entry->dev	   = rq->rq_disk ? disk_devt(rq->rq_disk) : 0;
+		__entry->sector    = blk_pc_request(rq) ? 0 : rq->hard_sector;
+		__entry->nr_sector = blk_pc_request(rq) ?
+						0 : rq->hard_nr_sectors;
+		__entry->errors    = rq->errors;
+
+		blk_fill_rwbs_rq(__entry->rwbs, rq);
+		blk_dump_cmd(__get_str(cmd), rq);
+	),
+
+	TP_printk("%d,%d %s (%s) %llu + %u [%d]",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->rwbs, __get_str(cmd),
+		  __entry->sector, __entry->nr_sector, __entry->errors)
+);
+
+TRACE_EVENT(block_rq_insert,
+
+	TP_PROTO(struct request_queue *q, struct request *rq),
+
+	TP_ARGS(q, rq),
+
+	TP_STRUCT__entry(
+		__field(  dev_t,	dev			)
+		__field(  sector_t,	sector			)
+		__field(  unsigned int,	nr_sector		)
+		__field(  unsigned int,	bytes			)
+		__array(  char,		rwbs,	6		)
+		__array(  char,         comm,   TASK_COMM_LEN   )
+		__dynamic_array( char,	cmd,	blk_cmd_buf_len(rq)	)
+	),
+
+	TP_fast_assign(
+		__entry->dev	   = rq->rq_disk ? disk_devt(rq->rq_disk) : 0;
+		__entry->sector    = blk_pc_request(rq) ? 0 : rq->hard_sector;
+		__entry->nr_sector = blk_pc_request(rq) ?
+						0 : rq->hard_nr_sectors;
+		__entry->bytes     = blk_pc_request(rq) ? rq->data_len : 0;
+
+		blk_fill_rwbs_rq(__entry->rwbs, rq);
+		blk_dump_cmd(__get_str(cmd), rq);
+		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+	),
+
+	TP_printk("%d,%d %s %u (%s) %llu + %u [%s]",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->rwbs, __entry->bytes, __get_str(cmd),
+		  __entry->sector, __entry->nr_sector, __entry->comm)
+);
+
+TRACE_EVENT(block_rq_issue,
+
+	TP_PROTO(struct request_queue *q, struct request *rq),
+
+	TP_ARGS(q, rq),
+
+	TP_STRUCT__entry(
+		__field(  dev_t,	dev			)
+		__field(  sector_t,	sector			)
+		__field(  unsigned int,	nr_sector		)
+		__field(  unsigned int,	bytes			)
+		__array(  char,		rwbs,	6		)
+		__array(  char,		comm,   TASK_COMM_LEN   )
+		__dynamic_array( char,	cmd,	blk_cmd_buf_len(rq)	)
+	),
+
+	TP_fast_assign(
+		__entry->dev	   = rq->rq_disk ? disk_devt(rq->rq_disk) : 0;
+		__entry->sector    = blk_pc_request(rq) ? 0 : rq->hard_sector;
+		__entry->nr_sector = blk_pc_request(rq) ?
+						0 : rq->hard_nr_sectors;
+		__entry->bytes     = blk_pc_request(rq) ? rq->data_len : 0;
+
+		blk_fill_rwbs_rq(__entry->rwbs, rq);
+		blk_dump_cmd(__get_str(cmd), rq);
+		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+	),
+
+	TP_printk("%d,%d %s %u (%s) %llu + %u [%s]",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->rwbs, __entry->bytes, __get_str(cmd),
+		  __entry->sector, __entry->nr_sector, __entry->comm)
+);
+
+TRACE_EVENT(block_rq_requeue,
+
+	TP_PROTO(struct request_queue *q, struct request *rq),
+
+	TP_ARGS(q, rq),
+
+	TP_STRUCT__entry(
+		__field(  dev_t,	dev			)
+		__field(  sector_t,	sector			)
+		__field(  unsigned int,	nr_sector		)
+		__field(  int,		errors			)
+		__array(  char,		rwbs,	6		)
+		__dynamic_array( char,	cmd,	blk_cmd_buf_len(rq)	)
+	),
+
+	TP_fast_assign(
+		__entry->dev	   = rq->rq_disk ? disk_devt(rq->rq_disk) : 0;
+		__entry->sector    = blk_pc_request(rq) ? 0 : rq->hard_sector;
+		__entry->nr_sector = blk_pc_request(rq) ?
+						0 : rq->hard_nr_sectors;
+		__entry->errors	   = rq->errors;
+
+		blk_fill_rwbs_rq(__entry->rwbs, rq);
+		blk_dump_cmd(__get_str(cmd), rq);
+	),
+
+	TP_printk("%d,%d %s (%s) %llu + %u [%d]",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->rwbs, __get_str(cmd),
+		  __entry->sector, __entry->nr_sector, __entry->errors)
+);
+
+TRACE_EVENT(block_rq_complete,
+
+	TP_PROTO(struct request_queue *q, struct request *rq),
+
+	TP_ARGS(q, rq),
+
+	TP_STRUCT__entry(
+		__field(  dev_t,	dev			)
+		__field(  sector_t,	sector			)
+		__field(  unsigned int,	nr_sector		)
+		__field(  int,		errors			)
+		__array(  char,		rwbs,	6		)
+		__dynamic_array( char,	cmd,	blk_cmd_buf_len(rq)	)
+	),
+
+	TP_fast_assign(
+		__entry->dev	   = rq->rq_disk ? disk_devt(rq->rq_disk) : 0;
+		__entry->sector    = blk_pc_request(rq) ? 0 : rq->hard_sector;
+		__entry->nr_sector = blk_pc_request(rq) ?
+						0 : rq->hard_nr_sectors;
+		__entry->errors    = rq->errors;
+
+		blk_fill_rwbs_rq(__entry->rwbs, rq);
+		blk_dump_cmd(__get_str(cmd), rq);
+	),
+
+	TP_printk("%d,%d %s (%s) %llu + %u [%d]",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->rwbs, __get_str(cmd),
+		  __entry->sector, __entry->nr_sector, __entry->errors)
+);
+TRACE_EVENT(block_bio_bounce,
+
+	TP_PROTO(struct request_queue *q, struct bio *bio),
+
+	TP_ARGS(q, bio),
+
+	TP_STRUCT__entry(
+		__field( dev_t,		dev			)
+		__field( sector_t,	sector			)
+		__field( unsigned int,	nr_sector		)
+		__array( char,		rwbs,	6		)
+		__array( char,		comm,	TASK_COMM_LEN	)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= bio->bi_bdev->bd_dev;
+		__entry->sector		= bio->bi_sector;
+		__entry->nr_sector	= bio->bi_size >> 9;
+		blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
+		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+	),
+
+	TP_printk("%d,%d %s %llu + %u [%s]",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
+		  __entry->sector, __entry->nr_sector, __entry->comm)
+);
+
+TRACE_EVENT(block_bio_complete,
+
+	TP_PROTO(struct request_queue *q, struct bio *bio),
+
+	TP_ARGS(q, bio),
+
+	TP_STRUCT__entry(
+		__field( dev_t,		dev		)
+		__field( sector_t,	sector		)
+		__field( unsigned,	nr_sector	)
+		__field( int,		error		)
+		__array( char,		rwbs,	6	)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= bio->bi_bdev->bd_dev;
+		__entry->sector		= bio->bi_sector;
+		__entry->nr_sector	= bio->bi_size >> 9;
+		blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
+	),
+
+	TP_printk("%d,%d %s %llu + %u [%d]",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
+		  __entry->sector, __entry->nr_sector, __entry->error)
+);
+
+TRACE_EVENT(block_bio_backmerge,
+
+	TP_PROTO(struct request_queue *q, struct bio *bio),
+
+	TP_ARGS(q, bio),
+
+	TP_STRUCT__entry(
+		__field( dev_t,		dev			)
+		__field( sector_t,	sector			)
+		__field( unsigned int,	nr_sector		)
+		__array( char,		rwbs,	6		)
+		__array( char,		comm,	TASK_COMM_LEN	)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= bio->bi_bdev->bd_dev;
+		__entry->sector		= bio->bi_sector;
+		__entry->nr_sector	= bio->bi_size >> 9;
+		blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
+		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+	),
+
+	TP_printk("%d,%d %s %llu + %u [%s]",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
+		  __entry->sector, __entry->nr_sector, __entry->comm)
+);
+
+TRACE_EVENT(block_bio_frontmerge,
+
+	TP_PROTO(struct request_queue *q, struct bio *bio),
+
+	TP_ARGS(q, bio),
+
+	TP_STRUCT__entry(
+		__field( dev_t,		dev			)
+		__field( sector_t,	sector			)
+		__field( unsigned,	nr_sector		)
+		__array( char,		rwbs,	6		)
+		__array( char,		comm,	TASK_COMM_LEN	)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= bio->bi_bdev->bd_dev;
+		__entry->sector		= bio->bi_sector;
+		__entry->nr_sector	= bio->bi_size >> 9;
+		blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
+		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+	),
+
+	TP_printk("%d,%d %s %llu + %u [%s]",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
+		  __entry->sector, __entry->nr_sector, __entry->comm)
+);
+
+TRACE_EVENT(block_bio_queue,
+
+	TP_PROTO(struct request_queue *q, struct bio *bio),
+
+	TP_ARGS(q, bio),
+
+	TP_STRUCT__entry(
+		__field( dev_t,		dev			)
+		__field( sector_t,	sector			)
+		__field( unsigned int,	nr_sector		)
+		__array( char,		rwbs,	6		)
+		__array( char,		comm,	TASK_COMM_LEN	)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= bio->bi_bdev->bd_dev;
+		__entry->sector		= bio->bi_sector;
+		__entry->nr_sector	= bio->bi_size >> 9;
+		blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
+		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+	),
+
+	TP_printk("%d,%d %s %llu + %u [%s]",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
+		  __entry->sector, __entry->nr_sector, __entry->comm)
+);
+
+TRACE_EVENT(block_getrq,
+
+	TP_PROTO(struct request_queue *q, struct bio *bio, int rw),
+
+	TP_ARGS(q, bio, rw),
+
+	TP_STRUCT__entry(
+		__field( dev_t,		dev			)
+		__field( sector_t,	sector			)
+		__field( unsigned int,	nr_sector		)
+		__array( char,		rwbs,	6		)
+		__array( char,		comm,	TASK_COMM_LEN	)
+        ),
+
+	TP_fast_assign(
+		__entry->dev		= bio ? bio->bi_bdev->bd_dev : 0;
+		__entry->sector		= bio ? bio->bi_sector : 0;
+		__entry->nr_sector	= bio ? bio->bi_size >> 9 : 0;
+		blk_fill_rwbs(__entry->rwbs,
+			      bio ? bio->bi_rw : 0, __entry->nr_sector);
+		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+        ),
+
+	TP_printk("%d,%d %s %llu + %u [%s]",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
+		  __entry->sector, __entry->nr_sector, __entry->comm)
+);
+
+TRACE_EVENT(block_sleeprq,
+
+	TP_PROTO(struct request_queue *q, struct bio *bio, int rw),
+
+	TP_ARGS(q, bio, rw),
+
+	TP_STRUCT__entry(
+		__field( dev_t,		dev			)
+		__field( sector_t,	sector			)
+		__field( unsigned int,	nr_sector		)
+		__array( char,		rwbs,	6		)
+		__array( char,		comm,	TASK_COMM_LEN	)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= bio ? bio->bi_bdev->bd_dev : 0;
+		__entry->sector		= bio ? bio->bi_sector : 0;
+		__entry->nr_sector	= bio ? bio->bi_size >> 9 : 0;
+		blk_fill_rwbs(__entry->rwbs,
+			    bio ? bio->bi_rw : 0, __entry->nr_sector);
+		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+	),
+
+	TP_printk("%d,%d %s %llu + %u [%s]",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
+		  __entry->sector, __entry->nr_sector, __entry->comm)
+);
+
+TRACE_EVENT(block_plug,
+
+	TP_PROTO(struct request_queue *q),
+
+	TP_ARGS(q),
+
+	TP_STRUCT__entry(
+		__array( char,		comm,	TASK_COMM_LEN	)
+	),
+
+	TP_fast_assign(
+		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+	),
+
+	TP_printk("[%s]", __entry->comm)
+);
+
+TRACE_EVENT(block_unplug_timer,
+
+	TP_PROTO(struct request_queue *q),
+
+	TP_ARGS(q),
+
+	TP_STRUCT__entry(
+		__field( int,		nr_rq			)
+		__array( char,		comm,	TASK_COMM_LEN	)
+	),
+
+	TP_fast_assign(
+		__entry->nr_rq	= q->rq.count[READ] + q->rq.count[WRITE];
+		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+	),
+
+	TP_printk("[%s] %d", __entry->comm, __entry->nr_rq)
+);
+
+TRACE_EVENT(block_unplug_io,
+
+	TP_PROTO(struct request_queue *q),
+
+	TP_ARGS(q),
+
+	TP_STRUCT__entry(
+		__field( int,		nr_rq			)
+		__array( char,		comm,	TASK_COMM_LEN	)
+	),
+
+	TP_fast_assign(
+		__entry->nr_rq	= q->rq.count[READ] + q->rq.count[WRITE];
+		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+	),
+
+	TP_printk("[%s] %d", __entry->comm, __entry->nr_rq)
+);
+
+TRACE_EVENT(block_split,
+
+	TP_PROTO(struct request_queue *q, struct bio *bio,
+		 unsigned int new_sector),
+
+	TP_ARGS(q, bio, new_sector),
+
+	TP_STRUCT__entry(
+		__field( dev_t,		dev				)
+		__field( sector_t,	sector				)
+		__field( sector_t,	new_sector			)
+		__array( char,		rwbs,		6		)
+		__array( char,		comm,		TASK_COMM_LEN	)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= bio->bi_bdev->bd_dev;
+		__entry->sector		= bio->bi_sector;
+		__entry->new_sector	= new_sector;
+		blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
+		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+	),
+
+	TP_printk("%d,%d %s %llu / %llu [%s]",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
+		  __entry->sector, __entry->new_sector, __entry->comm)
+);
+
+TRACE_EVENT(block_remap,
+
+	TP_PROTO(struct request_queue *q, struct bio *bio, dev_t dev,
+		 sector_t from),
+
+	TP_ARGS(q, bio, 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		= bio->bi_bdev->bd_dev;
+		__entry->sector		= bio->bi_sector;
+		__entry->nr_sector	= bio->bi_size >> 9;
+		__entry->old_dev	= dev;
+		__entry->old_sector	= from;
+		blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
+	),
+
+	TP_printk("%d,%d %s %llu + %u <- (%d,%d) %llu",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
+		  __entry->sector, __entry->nr_sector,
+		  MAJOR(__entry->old_dev), MINOR(__entry->old_dev),
+		  __entry->old_sector)
+);
+
+#endif /* _TRACE_BLOCK_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
+