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Subject[PATCH 04/11] block: add @req to bio_{front|back}_merge tracepoints
Date
bio_{front|back}_merge tracepoints report a bio merging into an
existing request but didn't specify which request the bio is being
merged into. Add @req to it. This makes it impossible to share the
event template with block_bio_queue - split it out.
@req isn't used or exported to userland at this point and there is no
userland visible behavior change. Later changes will make use of the
extra parameter.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
block/blk-core.c | 4 +-
include/trace/events/block.h | 45 +++++++++++++++++++++++++++++++----------
kernel/trace/blktrace.c | 2 +
3 files changed, 38 insertions(+), 13 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index ea70e6c..b0b5411 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1180,7 +1180,7 @@ static bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
if (!ll_back_merge_fn(q, req, bio))
return false;

- trace_block_bio_backmerge(q, bio);
+ trace_block_bio_backmerge(q, req, bio);

if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
blk_rq_set_mixed_merge(req);
@@ -1203,7 +1203,7 @@ static bool bio_attempt_front_merge(struct request_queue *q,
if (!ll_front_merge_fn(q, req, bio))
return false;

- trace_block_bio_frontmerge(q, bio);
+ trace_block_bio_frontmerge(q, req, bio);

if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
blk_rq_set_mixed_merge(req);
diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index 05c5e61..983f8a8 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -241,11 +241,11 @@ TRACE_EVENT(block_bio_complete,
__entry->nr_sector, __entry->error)
);

-DECLARE_EVENT_CLASS(block_bio,
+DECLARE_EVENT_CLASS(block_bio_merge,

- TP_PROTO(struct request_queue *q, struct bio *bio),
+ TP_PROTO(struct request_queue *q, struct request *rq, struct bio *bio),

- TP_ARGS(q, bio),
+ TP_ARGS(q, rq, bio),

TP_STRUCT__entry(
__field( dev_t, dev )
@@ -272,31 +272,33 @@ DECLARE_EVENT_CLASS(block_bio,
/**
* block_bio_backmerge - merging block operation to the end of an existing operation
* @q: queue holding operation
+ * @rq: request bio is being merged into
* @bio: new block operation to merge
*
* Merging block request @bio to the end of an existing block request
* in queue @q.
*/
-DEFINE_EVENT(block_bio, block_bio_backmerge,
+DEFINE_EVENT(block_bio_merge, block_bio_backmerge,

- TP_PROTO(struct request_queue *q, struct bio *bio),
+ TP_PROTO(struct request_queue *q, struct request *rq, struct bio *bio),

- TP_ARGS(q, bio)
+ TP_ARGS(q, rq, bio)
);

/**
* block_bio_frontmerge - merging block operation to the beginning of an existing operation
* @q: queue holding operation
+ * @rq: request bio is being merged into
* @bio: new block operation to merge
*
* Merging block IO operation @bio to the beginning of an existing block
* operation in queue @q.
*/
-DEFINE_EVENT(block_bio, block_bio_frontmerge,
+DEFINE_EVENT(block_bio_merge, block_bio_frontmerge,

- TP_PROTO(struct request_queue *q, struct bio *bio),
+ TP_PROTO(struct request_queue *q, struct request *rq, struct bio *bio),

- TP_ARGS(q, bio)
+ TP_ARGS(q, rq, bio)
);

/**
@@ -306,11 +308,32 @@ DEFINE_EVENT(block_bio, block_bio_frontmerge,
*
* About to place the block IO operation @bio into queue @q.
*/
-DEFINE_EVENT(block_bio, block_bio_queue,
+TRACE_EVENT(block_bio_queue,

TP_PROTO(struct request_queue *q, struct bio *bio),

- TP_ARGS(q, bio)
+ TP_ARGS(q, bio),
+
+ TP_STRUCT__entry(
+ __field( dev_t, dev )
+ __field( sector_t, sector )
+ __field( unsigned int, nr_sector )
+ __array( char, rwbs, RWBS_LEN )
+ __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,
+ (unsigned long long)__entry->sector,
+ __entry->nr_sector, __entry->comm)
);

DECLARE_EVENT_CLASS(block_get_rq,
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 16fc34a..7d00bcf 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -797,6 +797,7 @@ static void blk_add_trace_bio_complete(void *ignore,

static void blk_add_trace_bio_backmerge(void *ignore,
struct request_queue *q,
+ struct request *rq,
struct bio *bio)
{
blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
@@ -804,6 +805,7 @@ static void blk_add_trace_bio_backmerge(void *ignore,

static void blk_add_trace_bio_frontmerge(void *ignore,
struct request_queue *q,
+ struct request *rq,
struct bio *bio)
{
blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
--
1.7.3.1


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