block: Add ioprio to block_rq tracepoint

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 RA 16384 () 6500840 + 32 be,0,6 [binder:815_3]
block_rq_issue: 8,0 RA 16384 () 6500840 + 32 be,0,6 [binder:815_3]
block_rq_complete: 8,0 RA () 6500840 + 32 be,0,6 [0]

Signed-off-by: Dongliang Cui <[email protected]>
Reviewed-by: Bart Van Assche <[email protected]>
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

Author: Dongliang Cui

include/trace/events/block.h

@@ -9,9 +9,17 @@
 #include <linux/blkdev.h>
 #include <linux/buffer_head.h>
 #include <linux/tracepoint.h>
+#include <uapi/linux/ioprio.h>
 
 #define RWBS_LEN	8
 
+#define IOPRIO_CLASS_STRINGS \
+	{ IOPRIO_CLASS_NONE,	"none" }, \
+	{ IOPRIO_CLASS_RT,	"rt" }, \
+	{ IOPRIO_CLASS_BE,	"be" }, \
+	{ IOPRIO_CLASS_IDLE,	"idle" }, \
+	{ IOPRIO_CLASS_INVALID,	"invalid"}
+
 #ifdef CONFIG_BUFFER_HEAD
 DECLARE_EVENT_CLASS(block_buffer,
 
@@ -82,6 +90,7 @@ TRACE_EVENT(block_rq_requeue,
 		__field(  dev_t,	dev			)
 		__field(  sector_t,	sector			)
 		__field(  unsigned int,	nr_sector		)
+		__field(  unsigned short, ioprio		)
 		__array(  char,		rwbs,	RWBS_LEN	)
 		__dynamic_array( char,	cmd,	1		)
 	),
@@ -90,16 +99,20 @@ TRACE_EVENT(block_rq_requeue,
 		__entry->dev	   = rq->q->disk ? disk_devt(rq->q->disk) : 0;
 		__entry->sector    = blk_rq_trace_sector(rq);
 		__entry->nr_sector = blk_rq_trace_nr_sectors(rq);
+		__entry->ioprio    = rq->ioprio;
 
 		blk_fill_rwbs(__entry->rwbs, rq->cmd_flags);
 		__get_str(cmd)[0] = '\0';
 	),
 
-	TP_printk("%d,%d %s (%s) %llu + %u [%d]",
+	TP_printk("%d,%d %s (%s) %llu + %u %s,%u,%u [%d]",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->rwbs, __get_str(cmd),
-		  (unsigned long long)__entry->sector,
-		  __entry->nr_sector, 0)
+		  (unsigned long long)__entry->sector, __entry->nr_sector,
+		  __print_symbolic(IOPRIO_PRIO_CLASS(__entry->ioprio),
+				   IOPRIO_CLASS_STRINGS),
+		  IOPRIO_PRIO_HINT(__entry->ioprio),
+		  IOPRIO_PRIO_LEVEL(__entry->ioprio),  0)
 );
 
 DECLARE_EVENT_CLASS(block_rq_completion,
@@ -113,6 +126,7 @@ DECLARE_EVENT_CLASS(block_rq_completion,
 		__field(  sector_t,	sector			)
 		__field(  unsigned int,	nr_sector		)
 		__field(  int	,	error			)
+		__field(  unsigned short, ioprio		)
 		__array(  char,		rwbs,	RWBS_LEN	)
 		__dynamic_array( char,	cmd,	1		)
 	),
@@ -122,16 +136,20 @@ DECLARE_EVENT_CLASS(block_rq_completion,
 		__entry->sector    = blk_rq_pos(rq);
 		__entry->nr_sector = nr_bytes >> 9;
 		__entry->error     = blk_status_to_errno(error);
+		__entry->ioprio    = rq->ioprio;
 
 		blk_fill_rwbs(__entry->rwbs, rq->cmd_flags);
 		__get_str(cmd)[0] = '\0';
 	),
 
-	TP_printk("%d,%d %s (%s) %llu + %u [%d]",
+	TP_printk("%d,%d %s (%s) %llu + %u %s,%u,%u [%d]",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->rwbs, __get_str(cmd),
-		  (unsigned long long)__entry->sector,
-		  __entry->nr_sector, __entry->error)
+		  (unsigned long long)__entry->sector, __entry->nr_sector,
+		  __print_symbolic(IOPRIO_PRIO_CLASS(__entry->ioprio),
+				   IOPRIO_CLASS_STRINGS),
+		  IOPRIO_PRIO_HINT(__entry->ioprio),
+		  IOPRIO_PRIO_LEVEL(__entry->ioprio), __entry->error)
 );
 
 /**
@@ -180,6 +198,7 @@ DECLARE_EVENT_CLASS(block_rq,
 		__field(  sector_t,	sector			)
 		__field(  unsigned int,	nr_sector		)
 		__field(  unsigned int,	bytes			)
+		__field(  unsigned short, ioprio		)
 		__array(  char,		rwbs,	RWBS_LEN	)
 		__array(  char,         comm,   TASK_COMM_LEN   )
 		__dynamic_array( char,	cmd,	1		)
@@ -190,17 +209,21 @@ DECLARE_EVENT_CLASS(block_rq,
 		__entry->sector    = blk_rq_trace_sector(rq);
 		__entry->nr_sector = blk_rq_trace_nr_sectors(rq);
 		__entry->bytes     = blk_rq_bytes(rq);
+		__entry->ioprio	   = rq->ioprio;
 
 		blk_fill_rwbs(__entry->rwbs, rq->cmd_flags);
 		__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,%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)
+		  (unsigned long long)__entry->sector, __entry->nr_sector,
+		  __print_symbolic(IOPRIO_PRIO_CLASS(__entry->ioprio),
+				   IOPRIO_CLASS_STRINGS),
+		  IOPRIO_PRIO_HINT(__entry->ioprio),
+		  IOPRIO_PRIO_LEVEL(__entry->ioprio), __entry->comm)
 );
 
 /**