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block: introduce block_io_start/block_io_done tracepoints

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Currently, several BCC ([0]) tools (biosnoop/biostacks/biotop) use
kprobes to blk_account_io_start/blk_account_io_done to implement
their functionalities. This is fragile because the target kernel
functions may be renamed ([1]) or inlined ([2]). So introduce two
new tracepoints for such use cases.

  [0]: https://github.com/iovisor/bcc
  [1]: https://github.com/iovisor/bcc/issues/3954
  [2]: https://github.com/iovisor/bcc/issues/4261

Tested-by: Francis Laniel <flaniel@linux.microsoft.com>
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Tested-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230520084057.1467003-1-hengqi.chen@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Hengqi Chen 2023-05-20 08:40:57 +00:00 committed by Jens Axboe
parent a13bd91be2
commit 5a80bd075f
2 changed files with 30 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

4
block/blk-mq.c
View file

@ -962,6 +962,8 @@ EXPORT_SYMBOL_GPL(blk_update_request);
static inline void blk_account_io_done(struct request *req, u64 now) static inline void blk_account_io_done(struct request *req, u64 now)
{ {
trace_block_io_done(req);
/* /*
* Account IO completion. flush_rq isn't accounted as a * Account IO completion. flush_rq isn't accounted as a
* normal IO on queueing nor completion. Accounting the * normal IO on queueing nor completion. Accounting the
@ -981,6 +983,8 @@ static inline void blk_account_io_done(struct request *req, u64 now)
static inline void blk_account_io_start(struct request *req) static inline void blk_account_io_start(struct request *req)
{ {
trace_block_io_start(req);
if (blk_do_io_stat(req)) { if (blk_do_io_stat(req)) {
/* /*
* All non-passthrough requests are created from a bio with one * All non-passthrough requests are created from a bio with one

26
include/trace/events/block.h
View file

@ -245,6 +245,32 @@ DEFINE_EVENT(block_rq, block_rq_merge,
TP_ARGS(rq) TP_ARGS(rq)
); );
/**
* block_io_start - insert a request for execution
* @rq: block IO operation request
*
* Called when block operation request @rq is queued for execution
*/
DEFINE_EVENT(block_rq, block_io_start,
TP_PROTO(struct request *rq),
TP_ARGS(rq)
);
/**
* block_io_done - block IO operation request completed
* @rq: block IO operation request
*
* Called when block operation request @rq is completed
*/
DEFINE_EVENT(block_rq, block_io_done,
TP_PROTO(struct request *rq),
TP_ARGS(rq)
);
/** /**
* block_bio_complete - completed all work on the block operation * block_bio_complete - completed all work on the block operation
* @q: queue holding the block operation * @q: queue holding the block operation