@@ -460,14 +460,18 @@ TRACE_EVENT(block_plug,
TP_ARGS(q),
TP_STRUCT__entry(
+ __field( dev_t, dev )
__array( char, comm, TASK_COMM_LEN )
),
TP_fast_assign(
+ __entry->dev = q->kobj.parent ?
+ container_of(q->kobj.parent, struct device, kobj)->devt : 0;
memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
),
- TP_printk("[%s]", __entry->comm)
+ TP_printk("%d,%d [%s]",
+ MAJOR(__entry->dev), MINOR(__entry->dev), __entry->comm)
);
#define show_block_unplug_explicit(val) \
@@ -482,18 +486,23 @@ DECLARE_EVENT_CLASS(block_unplug,
TP_ARGS(q, depth, explicit),
TP_STRUCT__entry(
+ __field( dev_t, dev )
__field( int, nr_rq )
__field( bool, explicit )
__array( char, comm, TASK_COMM_LEN )
),
TP_fast_assign(
+ __entry->dev = q->kobj.parent ?
+ container_of(q->kobj.parent, struct device, kobj)->devt : 0;
__entry->nr_rq = depth;
__entry->explicit = explicit;
memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
),
- TP_printk("[%s] %d %s", __entry->comm, __entry->nr_rq,
+ TP_printk("%d,%d [%s] %d %s",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->comm, __entry->nr_rq,
show_block_unplug_explicit(__entry->explicit))
);
Complements v2.6.31 commit 55782138e47d ("tracing/events: convert block trace points to TRACE_EVENT()") to be equivalent to traditional blktrace output. Also this allows event filtering to not always get all (un)plug events. NB: The NULL pointer check for q->kobj.parent is certainly racy and I don't have enough experience if it's good enough for a trace event. The change did work for my cases (block device read/write I/O on zfcp-attached SCSI disks and dm-mpath on top). While I haven't seen any prior art using driver core (parent) relations for trace events, there are other cases using this when no direct pointer exists between objects, such as: #define to_scsi_target(d) container_of(d, struct scsi_target, dev) static inline struct scsi_target *scsi_target(struct scsi_device *sdev) { return to_scsi_target(sdev->sdev_gendev.parent); } This is the object model we make use of here: struct gendisk { struct hd_struct { struct device { /*container_of*/ struct kobject kobj; <--+ dev_t devt; /*deref*/ | } __dev; | } part0; | struct request_queue *queue; ..+ | } : | : | struct request_queue { <..............+ | /* queue kobject */ | struct kobject { | struct kobject *parent; --------+ } kobj; } The parent pointer comes from: #define disk_to_dev(disk) (&(disk)->part0.__dev) int blk_register_queue(struct gendisk *disk) struct device *dev = disk_to_dev(disk); struct request_queue *q = disk->queue; ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue"); ^^^parent $ ls -d /sys/block/sdf/queue /sys/block/sda/queue $ cat /sys/block/sdf/dev 80:0 A partition does not have its own request queue: $ cat /sys/block/sdf/sdf1/dev 8:81 $ ls -d /sys/block/sdf/sdf1/queue ls: cannot access '/sys/block/sdf/sdf1/queue': No such file or directory The difference to blktrace parsed output is that block events don't use the partition's minor number but the containing block device's minor number: $ dd if=/dev/sdf1 count=1 $ cat /sys/kernel/debug/tracing/trace block_bio_remap: 8,80 R 2048 + 32 <- (8,81) 0 block_bio_queue: 8,80 R 2048 + 32 [dd] block_getrq: 8,80 R 2048 + 32 [dd] block_plug: 8,80 [dd] ^^^^ block_rq_insert: 8,80 R 16384 () 2048 + 32 [dd] block_unplug: 8,80 [dd] 1 explicit ^^^^ block_rq_issue: 8,80 R 16384 () 2048 + 32 [dd] block_rq_complete: 8,80 R () 2048 + 32 [0] $ btrace /dev/sdf1 8,80 1 1 0.000000000 240240 A R 2048 + 32 <- (8,81) 0 8,81 1 2 0.000220890 240240 Q R 2048 + 32 [dd] 8,81 1 3 0.000229639 240240 G R 2048 + 32 [dd] 8,81 1 4 0.000231805 240240 P N [dd] ^^ 8,81 1 5 0.000234671 240240 I R 2048 + 32 [dd] 8,81 1 6 0.000236365 240240 U N [dd] 1 ^^ 8,81 1 7 0.000238527 240240 D R 2048 + 32 [dd] 8,81 2 2 0.000613741 0 C R 2048 + 32 [0] Signed-off-by: Steffen Maier <maier@linux.ibm.com> --- include/trace/events/block.h | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)