diff options
| author | Jun'ichi Nomura <j-nomura@ce.jp.nec.com> | 2009-12-10 23:52:25 +0000 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2009-12-10 23:52:25 +0000 |
| commit | 6db4ccd6357f28c9ef7058b3bc48904c4b2ac419 (patch) | |
| tree | affd099b88123c0717ec4bbfbb2503c3d7cc91f8 /drivers/md/dm.c | |
| parent | c1f0c183f6acc6d32c5a1d0249ec68bf783af7b1 (diff) | |
dm: trace request based remapping
This patch adds a remapping trace to request-based dm.
BIO-based dm already has the equivalent tracepoint.
For example, under this dm stack (linear LV on multipath):
# dmsetup ls --tree -o ascii
vg-lv0 (253:1)
`-mpath0 (253:0)
|- (8:160)
|- (66:80)
|- (65:176)
`- (65:160)
Trace of 'dd of=/dev/vg/lv0 bs=128k count=1 oflag=direct' looks like this:
without the patch:
dd-6674 [000] 539.727384: block_bio_queue: 253,1 WS 0 + 256 [dd]
dd-6674 [000] 539.727392: block_remap: 253,0 WS 384 + 256 <- (253,1) 0
dd-6674 [000] 539.727394: block_bio_queue: 253,0 WS 384 + 256 [dd]
dd-6674 [000] 539.727405: block_getrq: 253,0 WS 384 + 256 [dd]
dd-6674 [000] 539.727409: block_plug: [dd]
dd-6674 [000] 539.727410: block_rq_insert: 253,0 W 0 () 384 + 256 [dd]
dd-6674 [000] 539.727416: block_rq_issue: 253,0 W 0 () 384 + 256 [dd]
dd-6674 [000] 539.727426: block_rq_insert: 65,176 W 0 () 384 + 256 [dd]
dd-6674 [000] 539.727427: block_rq_issue: 65,176 W 0 () 384 + 256 [dd]
...
and with the patch: (the line with '**' is the trace added by this patch)
dd-6617 [002] 162.914301: block_bio_queue: 253,1 WS 0 + 256 [dd]
dd-6617 [002] 162.914314: block_remap: 253,0 WS 384 + 256 <- (253,1) 0
dd-6617 [002] 162.914316: block_bio_queue: 253,0 WS 384 + 256 [dd]
dd-6617 [002] 162.914331: block_getrq: 253,0 WS 384 + 256 [dd]
dd-6617 [002] 162.914335: block_plug: [dd]
dd-6617 [002] 162.914337: block_rq_insert: 253,0 W 0 () 384 + 256 [dd]
dd-6617 [002] 162.914347: block_rq_issue: 253,0 W 0 () 384 + 256 [dd]
**dd-6617 [002] 162.914356: block_rq_remap: 65,176 W 384 + 256 <- (253,0) 384
dd-6617 [002] 162.914358: block_rq_insert: 65,176 W 0 () 384 + 256 [dd]
dd-6617 [002] 162.914359: block_rq_issue: 65,176 W 0 () 384 + 256 [dd]
...
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm.c')
| -rw-r--r-- | drivers/md/dm.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index c254c6cf69a..40e257fadac 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1618,6 +1618,8 @@ static void map_request(struct dm_target *ti, struct request *clone, break; case DM_MAPIO_REMAPPED: /* The target has remapped the I/O so dispatch it */ + trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)), + blk_rq_pos(tio->orig)); dm_dispatch_request(clone); break; case DM_MAPIO_REQUEUE: |