Commit af5040da authored by Roman Pen's avatar Roman Pen Committed by Jens Axboe
Browse files

blktrace: fix accounting of partially completed requests 



trace_block_rq_complete does not take into account that request can
be partially completed, so we can get the following incorrect output
of blkparser:

  C   R 232 + 240 [0]
  C   R 240 + 232 [0]
  C   R 248 + 224 [0]
  C   R 256 + 216 [0]

but should be:

  C   R 232 + 8 [0]
  C   R 240 + 8 [0]
  C   R 248 + 8 [0]
  C   R 256 + 8 [0]

Also, the whole output summary statistics of completed requests and
final throughput will be incorrect.

This patch takes into account real completion size of the request and
fixes wrong completion accounting.

Signed-off-by: default avatarRoman Pen <r.peniaev@gmail.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: linux-kernel@vger.kernel.org
Cc: stable@kernel.org
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent c46fff2a

block/blk-core.c

+1 −1
Original line number Diff line number Diff line
@@ -2354,7 +2354,7 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes) 
	if (!req->bio)

		return false;



	trace_block_rq_complete(req->q, req);

	trace_block_rq_complete(req->q, req, nr_bytes);



	/*

	 * For fs requests, rq is just carrier of independent bio's

block/blk-mq.c

+1 −1
Original line number Diff line number Diff line
@@ -309,7 +309,7 @@ void blk_mq_end_io(struct request *rq, int error) 
	struct bio *bio = rq->bio;

	unsigned int bytes = 0;



	trace_block_rq_complete(rq->q, rq);

	trace_block_rq_complete(rq->q, rq, blk_rq_bytes(rq));



	while (bio) {

		struct bio *next = bio->bi_next;

include/trace/events/block.h

+30 −3
Original line number Diff line number Diff line
@@ -132,6 +132,7 @@ DEFINE_EVENT(block_rq_with_error, block_rq_requeue, 
 * block_rq_complete - block IO operation completed by device driver

 * @q: queue containing the block operation request

 * @rq: block operations request

 * @nr_bytes: number of completed bytes

 *

 * The block_rq_complete tracepoint event indicates that some portion

 * of operation request has been completed by the device driver.  If
@@ -139,11 +140,37 @@ DEFINE_EVENT(block_rq_with_error, block_rq_requeue, 
 * do for the request. If @rq->bio is non-NULL then there is

 * additional work required to complete the request.

 */

DEFINE_EVENT(block_rq_with_error, block_rq_complete,

TRACE_EVENT(block_rq_complete,



	TP_PROTO(struct request_queue *q, struct request *rq),

	TP_PROTO(struct request_queue *q, struct request *rq,

		 unsigned int nr_bytes),



	TP_ARGS(q, rq)

	TP_ARGS(q, rq, nr_bytes),



	TP_STRUCT__entry(

		__field(  dev_t,	dev			)

		__field(  sector_t,	sector			)

		__field(  unsigned int,	nr_sector		)

		__field(  int,		errors			)

		__array(  char,		rwbs,	RWBS_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_rq_pos(rq);

		__entry->nr_sector = nr_bytes >> 9;

		__entry->errors    = rq->errors;



		blk_fill_rwbs(__entry->rwbs, rq->cmd_flags, nr_bytes);

		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),

		  (unsigned long long)__entry->sector,

		  __entry->nr_sector, __entry->errors)

);



DECLARE_EVENT_CLASS(block_rq,

kernel/trace/blktrace.c

+11 −9
Original line number Diff line number Diff line
@@ -702,6 +702,7 @@ void blk_trace_shutdown(struct request_queue *q) 
 * blk_add_trace_rq - Add a trace for a request oriented action

 * @q:		queue the io is for

 * @rq:		the source request

 * @nr_bytes:	number of completed bytes

 * @what:	the action

 *

 * Description:
@@ -709,7 +710,7 @@ void blk_trace_shutdown(struct request_queue *q) 
 *

 **/

static void blk_add_trace_rq(struct request_queue *q, struct request *rq,

			     u32 what)

			     unsigned int nr_bytes, u32 what)

{

	struct blk_trace *bt = q->blk_trace;
@@ -718,11 +719,11 @@ static void blk_add_trace_rq(struct request_queue *q, struct request *rq, 


	if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {

		what |= BLK_TC_ACT(BLK_TC_PC);

		__blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags,

		__blk_add_trace(bt, 0, nr_bytes, rq->cmd_flags,

				what, rq->errors, rq->cmd_len, rq->cmd);

	} else  {

		what |= BLK_TC_ACT(BLK_TC_FS);

		__blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),

		__blk_add_trace(bt, blk_rq_pos(rq), nr_bytes,

				rq->cmd_flags, what, rq->errors, 0, NULL);

	}

}
@@ -730,33 +731,34 @@ static void blk_add_trace_rq(struct request_queue *q, struct request *rq, 
static void blk_add_trace_rq_abort(void *ignore,

				   struct request_queue *q, struct request *rq)

{

	blk_add_trace_rq(q, rq, BLK_TA_ABORT);

	blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ABORT);

}



static void blk_add_trace_rq_insert(void *ignore,

				    struct request_queue *q, struct request *rq)

{

	blk_add_trace_rq(q, rq, BLK_TA_INSERT);

	blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_INSERT);

}



static void blk_add_trace_rq_issue(void *ignore,

				   struct request_queue *q, struct request *rq)

{

	blk_add_trace_rq(q, rq, BLK_TA_ISSUE);

	blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ISSUE);

}



static void blk_add_trace_rq_requeue(void *ignore,

				     struct request_queue *q,

				     struct request *rq)

{

	blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);

	blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_REQUEUE);

}



static void blk_add_trace_rq_complete(void *ignore,

				      struct request_queue *q,

				      struct request *rq)

				      struct request *rq,

				      unsigned int nr_bytes)

{

	blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);

	blk_add_trace_rq(q, rq, nr_bytes, BLK_TA_COMPLETE);

}



/**

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