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[V7,2/2] block: introduce block_rq_error tracepoint

Message ID 20220205091150.6105-3-chaitanyak@nvidia.com (mailing list archive)
State New, archived
Headers show
Series [V7,1/2] block: create event class for rq completion | expand

Commit Message

Chaitanya Kulkarni Feb. 5, 2022, 9:11 a.m. UTC 
From: Chaitanya Kulkarni <kch@nvidia.com>

From: Yang Shi <shy828301@gmail.com>

Currently, rasdaemon uses the existing tracepoint block_rq_complete
and filters out non-error cases in order to capture block disk errors.

But there are a few problems with this approach:

1. Even kernel trace filter could do the filtering work, there is
   still some overhead after we enable this tracepoint.

2. The filter is merely based on errno, which does not align with kernel
   logic to check the errors for print_req_error().

3. block_rq_complete only provides dev major and minor to identify
   the block device, it is not convenient to use in user-space.

So introduce a new tracepoint block_rq_error just for the error case.
With this patch, rasdaemon could switch to block_rq_error.

Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
[kch]: instead of adding new event reuse the code from
block_rq_competion for block_rq_error.
Signed-off-by: Yang Shi <shy828301@gmail.com>
---
 block/blk-mq.c               |  4 +++-
 include/trace/events/block.h | 16 ++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)
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Patch

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4b868e792ba4..6c59ffe765fd 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -789,8 +789,10 @@  bool blk_update_request(struct request *req, blk_status_t error,
 #endif
 
 	if (unlikely(error && !blk_rq_is_passthrough(req) &&
-		     !(req->rq_flags & RQF_QUIET)))
+		     !(req->rq_flags & RQF_QUIET))) {
 		blk_print_req_error(req, error);
+		trace_block_rq_error(req, error, nr_bytes);
+	}
 
 	blk_account_io_completion(req, nr_bytes);
 
diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index 1519068bd1ab..7f4dfbdf12a6 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -151,6 +151,22 @@  DEFINE_EVENT(block_rq_completion, block_rq_complete,
 	TP_ARGS(rq, error, nr_bytes)
 );
 
+/**
+ * block_rq_error - block IO operation error reported by device driver
+ * @rq: block operations request
+ * @error: status code
+ * @nr_bytes: number of completed bytes
+ *
+ * The block_rq_error tracepoint event indicates that some portion
+ * of operation request has failed as reported by the device driver.
+ */
+DEFINE_EVENT(block_rq_completion, block_rq_error,
+
+	TP_PROTO(struct request *rq, blk_status_t error, unsigned int nr_bytes),
+
+	TP_ARGS(rq, error, nr_bytes)
+);
+
 DECLARE_EVENT_CLASS(block_rq,
 
 	TP_PROTO(struct request *rq),