block: Add ioprio to block_rq tracepoint

Commit Message

Dongliang Cui April 10, 2024, 10:14 a.m. UTC

Sometimes we need to track the processing order of requests with
ioprio set. So the ioprio of request can be useful information.

Example：

block_rq_insert: 8,0 WS 4096 () 16573296 + 8 rt,4 [highpool[1]]
block_rq_issue: 8,0 WS 4096 () 16573296 + 8 rt,4 [kworker/7:0H]
block_rq_complete: 8,0 WS () 16573296 + 8 rt,4 [0]

Signed-off-by: Dongliang Cui <[e-mail]>
---
 include/linux/blktrace_api.h |  2 ++
 include/trace/events/block.h | 63 ++++++++++++++++++++++--------------
 kernel/trace/blktrace.c      | 11 +++++++
 3 files changed, 51 insertions(+), 25 deletions(-)

Patch

diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
index 122c62e561fc..adb0333efbdb 100644
--- a/include/linux/blktrace_api.h
+++ b/include/linux/blktrace_api.h
@@ -112,6 +112,8 @@  struct compat_blk_user_trace_setup {
 
 void blk_fill_rwbs(char *rwbs, blk_opf_t opf);
 
+void blk_fill_ioprio(u32 ioprio, char *ioprio_class, u32 *ioprio_value);
+
 static inline sector_t blk_rq_trace_sector(struct request *rq)
 {
 	/*
diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index 0e128ad51460..1d41fade160a 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -10,7 +10,8 @@ 
 #include <linux/buffer_head.h>
 #include <linux/tracepoint.h>
 
-#define RWBS_LEN	8
+#define RWBS_LEN		8
+#define IOPRIO_CLASS_LEN	8
 
 #ifdef CONFIG_BUFFER_HEAD
 DECLARE_EVENT_CLASS(block_buffer,
@@ -79,11 +80,13 @@  TRACE_EVENT(block_rq_requeue,
 	TP_ARGS(rq),
 
 	TP_STRUCT__entry(
-		__field(  dev_t,	dev			)
-		__field(  sector_t,	sector			)
-		__field(  unsigned int,	nr_sector		)
-		__array(  char,		rwbs,	RWBS_LEN	)
-		__dynamic_array( char,	cmd,	1		)
+		__field(  dev_t,	dev				)
+		__field(  sector_t,	sector				)
+		__field(  unsigned int,	nr_sector			)
+		__array(  char,		rwbs,	RWBS_LEN		)
+		__array(  char,		ioprio_class, IOPRIO_CLASS_LEN	)
+		__field(  unsigned int, ioprio_value			)
+		__dynamic_array( char,	cmd,	1			)
 	),
 
 	TP_fast_assign(
@@ -92,14 +95,16 @@  TRACE_EVENT(block_rq_requeue,
 		__entry->nr_sector = blk_rq_trace_nr_sectors(rq);
 
 		blk_fill_rwbs(__entry->rwbs, rq->cmd_flags);
+		blk_fill_ioprio(rq->ioprio, __entry->ioprio_class, &__entry->ioprio_value);
 		__get_str(cmd)[0] = '\0';
 	),
 
-	TP_printk("%d,%d %s (%s) %llu + %u [%d]",
+	TP_printk("%d,%d %s (%s) %llu + %u %s,%u [%d]",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->rwbs, __get_str(cmd),
 		  (unsigned long long)__entry->sector,
-		  __entry->nr_sector, 0)
+		  __entry->nr_sector, __entry->ioprio_class,
+		  __entry->ioprio_value, 0)
 );
 
 DECLARE_EVENT_CLASS(block_rq_completion,
@@ -109,12 +114,14 @@  DECLARE_EVENT_CLASS(block_rq_completion,
 	TP_ARGS(rq, error, nr_bytes),
 
 	TP_STRUCT__entry(
-		__field(  dev_t,	dev			)
-		__field(  sector_t,	sector			)
-		__field(  unsigned int,	nr_sector		)
-		__field(  int	,	error			)
-		__array(  char,		rwbs,	RWBS_LEN	)
-		__dynamic_array( char,	cmd,	1		)
+		__field(  dev_t,	dev				)
+		__field(  sector_t,	sector				)
+		__field(  unsigned int,	nr_sector			)
+		__field(  int,		error				)
+		__array(  char,		rwbs,	RWBS_LEN		)
+		__array(  char,		ioprio_class, IOPRIO_CLASS_LEN	)
+		__field(  unsigned int,	ioprio_value			)
+		__dynamic_array( char,	cmd,	1			)
 	),
 
 	TP_fast_assign(
@@ -124,14 +131,16 @@  DECLARE_EVENT_CLASS(block_rq_completion,
 		__entry->error     = blk_status_to_errno(error);
 
 		blk_fill_rwbs(__entry->rwbs, rq->cmd_flags);
+		blk_fill_ioprio(rq->ioprio, __entry->ioprio_class, &__entry->ioprio_value);
 		__get_str(cmd)[0] = '\0';
 	),
 
-	TP_printk("%d,%d %s (%s) %llu + %u [%d]",
+	TP_printk("%d,%d %s (%s) %llu + %u %s,%u [%d]",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->rwbs, __get_str(cmd),
 		  (unsigned long long)__entry->sector,
-		  __entry->nr_sector, __entry->error)
+		  __entry->nr_sector, __entry->ioprio_class,
+		  __entry->ioprio_value, __entry->error)
 );
 
 /**
@@ -176,13 +185,15 @@  DECLARE_EVENT_CLASS(block_rq,
 	TP_ARGS(rq),
 
 	TP_STRUCT__entry(
-		__field(  dev_t,	dev			)
-		__field(  sector_t,	sector			)
-		__field(  unsigned int,	nr_sector		)
-		__field(  unsigned int,	bytes			)
-		__array(  char,		rwbs,	RWBS_LEN	)
-		__array(  char,         comm,   TASK_COMM_LEN   )
-		__dynamic_array( char,	cmd,	1		)
+		__field(  dev_t,	dev				)
+		__field(  sector_t,	sector				)
+		__field(  unsigned int,	nr_sector			)
+		__field(  unsigned int,	bytes				)
+		__array(  char,		rwbs,	RWBS_LEN		)
+		__array(  char,		ioprio_class, IOPRIO_CLASS_LEN	)
+		__field(  unsigned int,	ioprio_value			)
+		__array(  char,		comm,   TASK_COMM_LEN		)
+		__dynamic_array( char,	cmd,	1			)
 	),
 
 	TP_fast_assign(
@@ -192,15 +203,17 @@  DECLARE_EVENT_CLASS(block_rq,
 		__entry->bytes     = blk_rq_bytes(rq);
 
 		blk_fill_rwbs(__entry->rwbs, rq->cmd_flags);
+		blk_fill_ioprio(rq->ioprio, __entry->ioprio_class, &__entry->ioprio_value);
 		__get_str(cmd)[0] = '\0';
 		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
 	),
 
-	TP_printk("%d,%d %s %u (%s) %llu + %u [%s]",
+	TP_printk("%d,%d %s %u (%s) %llu + %u %s,%u [%s]",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->rwbs, __entry->bytes, __get_str(cmd),
 		  (unsigned long long)__entry->sector,
-		  __entry->nr_sector, __entry->comm)
+		  __entry->nr_sector, __entry->ioprio_class,
+		  __entry->ioprio_value, __entry->comm)
 );
 
 /**
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index d5d94510afd3..e55aa49f94db 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -19,6 +19,7 @@ 
 #include <linux/uaccess.h>
 #include <linux/list.h>
 #include <linux/blk-cgroup.h>
+#include <linux/ioprio.h>
 
 #include "../../block/blk.h"
 
@@ -26,6 +27,9 @@ 
 
 #include "trace_output.h"
 
+/* Type of ioprio */
+static char *classes[] = {"none", "rt", "be", "idle"};
+
 #ifdef CONFIG_BLK_DEV_IO_TRACE
 
 static unsigned int blktrace_seq __read_mostly = 1;
@@ -1914,5 +1918,12 @@  void blk_fill_rwbs(char *rwbs, blk_opf_t opf)
 }
 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
 
+void blk_fill_ioprio(u32 ioprio, char *ioprio_class, u32 *ioprio_value)
+{
+	memcpy(ioprio_class, classes[(ioprio >> IOPRIO_CLASS_SHIFT) & 0x3], IOPRIO_CLASS_LEN);
+	*ioprio_value = ioprio & 0xff;
+}
+EXPORT_SYMBOL_GPL(blk_fill_ioprio);
+
 #endif /* CONFIG_EVENT_TRACING */