diff options
| author | Mike Snitzer <snitzer@redhat.com> | 2022-02-17 23:40:32 -0500 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2022-02-21 15:36:33 -0500 |
| commit | 0fbb4d93b38bce1f8235aacfa37e90ad8f011473 (patch) | |
| tree | 0e952a46f944ff4559ebfd5d0579b1d766ef54cb /include/linux/device-mapper.h | |
| parent | e6fc9f62ce6e412acb1699a5373174aa42ca2bd3 (diff) | |
dm: add dm_submit_bio_remap interface
Where possible, switch from early bio-based IO accounting (at the time
DM clones each incoming bio) to late IO accounting just before each
remapped bio is issued to underlying device via submit_bio_noacct().
Allows more precise bio-based IO accounting for DM targets that use
their own workqueues to perform additional processing of each bio in
conjunction with their DM_MAPIO_SUBMITTED return from their map
function. When a target is updated to use dm_submit_bio_remap() they
must also set ti->accounts_remapped_io to true.
Use xchg() in start_io_acct(), as suggested by Mikulas, to ensure each
IO is only started once. The xchg race only happens if
__send_duplicate_bios() sends multiple bios -- that case is reflected
via tio->is_duplicate_bio. Given the niche nature of this race, it is
best to avoid any xchg performance penalty for normal IO.
For IO that was never submitted with dm_bio_submit_remap(), but the
target completes the clone with bio_endio, accounting is started then
ended and pending_io counter decremented.
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'include/linux/device-mapper.h')
| -rw-r--r-- | include/linux/device-mapper.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index b26fecf6c8e8..7752d14d13f8 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -362,6 +362,12 @@ struct dm_target { * zone append operations using regular writes. */ bool emulate_zone_append:1; + + /* + * Set if the target will submit IO using dm_submit_bio_remap() + * after returning DM_MAPIO_SUBMITTED from its map function. + */ + bool accounts_remapped_io:1; }; void *dm_per_bio_data(struct bio *bio, size_t data_size); @@ -465,6 +471,7 @@ int dm_suspended(struct dm_target *ti); int dm_post_suspending(struct dm_target *ti); int dm_noflush_suspending(struct dm_target *ti); void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors); +void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone, bool from_wq); union map_info *dm_get_rq_mapinfo(struct request *rq); #ifdef CONFIG_BLK_DEV_ZONED |