diff options
| author | Ming Lei <ming.lei@redhat.com> | 2026-01-16 22:18:44 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2026-01-22 20:05:40 -0700 |
| commit | e2723e6ce6025026b6d79d9a00048386a69e00c3 (patch) | |
| tree | ce5d052affd68ee14ce81bfcf9c2b8cecf465297 /include/uapi/linux | |
| parent | 29d0a927f9efd5f87ac8a2d291d2782384d1bee2 (diff) | |
ublk: add new feature UBLK_F_BATCH_IO
Add new feature UBLK_F_BATCH_IO which replaces the following two
per-io commands:
- UBLK_U_IO_FETCH_REQ
- UBLK_U_IO_COMMIT_AND_FETCH_REQ
with three per-queue batch io uring_cmd:
- UBLK_U_IO_PREP_IO_CMDS
- UBLK_U_IO_COMMIT_IO_CMDS
- UBLK_U_IO_FETCH_IO_CMDS
Then ublk can deliver batch io commands to ublk server in single
multishort uring_cmd, also allows to prepare & commit multiple
commands in batch style via single uring_cmd, communication cost is
reduced a lot.
This feature also doesn't limit task context any more for all supported
commands, so any allowed uring_cmd can be issued in any task context.
ublk server implementation becomes much easier.
Meantime load balance becomes much easier to support with this feature.
The command `UBLK_U_IO_FETCH_IO_CMDS` can be issued from multiple task
contexts, so each task can adjust this command's buffer length or number
of inflight commands for controlling how much load is handled by current
task.
Later, priority parameter will be added to command `UBLK_U_IO_FETCH_IO_CMDS`
for improving load balance support.
UBLK_U_IO_NEED_GET_DATA isn't supported in batch io yet, but it may be
enabled in future via its batch pair.
Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/uapi/linux')
| -rw-r--r-- | include/uapi/linux/ublk_cmd.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h index 70d8ebbf4326..743d31491387 100644 --- a/include/uapi/linux/ublk_cmd.h +++ b/include/uapi/linux/ublk_cmd.h @@ -341,6 +341,21 @@ #define UBLK_F_BUF_REG_OFF_DAEMON (1ULL << 14) /* + * Support the following commands for delivering & committing io command + * in batch. + * + * - UBLK_U_IO_PREP_IO_CMDS + * - UBLK_U_IO_COMMIT_IO_CMDS + * - UBLK_U_IO_FETCH_IO_CMDS + * - UBLK_U_IO_REGISTER_IO_BUF + * - UBLK_U_IO_UNREGISTER_IO_BUF + * + * The existing UBLK_U_IO_FETCH_REQ, UBLK_U_IO_COMMIT_AND_FETCH_REQ and + * UBLK_U_IO_NEED_GET_DATA uring_cmd are not supported for this feature. + */ +#define UBLK_F_BATCH_IO (1ULL << 15) + +/* * ublk device supports requests with integrity/metadata buffer. * Requires UBLK_F_USER_COPY. */ |