| Message ID | 4ABB1EA6.2070805@ce.jp.nec.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Alasdair Kergon |
| Headers | show |
Index: block-for-linus-2.6.32/drivers/md/dm.c =================================================================== --- block-for-linus-2.6.32.orig/drivers/md/dm.c +++ block-for-linus-2.6.32/drivers/md/dm.c @@ -1505,6 +1505,8 @@ static void map_request(struct dm_target 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:
# Re-sending just the dm part. Hi Alasdair, 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] ... The patch depends on the following commit, which is currently in Jens' for-linus tree (for 2.6.32). commit 0dcaf5b406a5e09ecbb80ad25434694457117e50 Author: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Date: Mon Sep 21 21:04:03 2009 +0200 Add a tracepoint for block request remapping The patch can apply either with or without the patch series for -next in your editing tree. If you are ok, please pull this patch to your tree for 2.6.32. 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: Alasdair G Kergon <agk@redhat.com> Cc: Li Zefan <lizf@cn.fujitsu.com> --- drivers/md/dm.c | 2 ++ 1 file changed, 2 insertions(+) -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel