diff options
| author | Josef Bacik <jbacik@fb.com> | 2016-11-22 14:04:40 -0500 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2016-11-22 12:16:32 -0700 |
| commit | 9561a7ade0c205bc2ee035a2ac880478dcc1a024 (patch) | |
| tree | 3c638cde9063a2461b9767ec626b4359445c662a /include/uapi | |
| parent | e00f4f4d0ff7e13b9115428a245b49108d625f09 (diff) | |
nbd: add multi-connection support
NBD can become contended on its single connection. We have to serialize all
writes and we can only process one read response at a time. Fix this by
allowing userspace to provide multiple connections to a single nbd device. This
coupled with block-mq drastically increases performance in multi-process cases.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'include/uapi')
| -rw-r--r-- | include/uapi/linux/nbd.h | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/include/uapi/linux/nbd.h b/include/uapi/linux/nbd.h index e08e413d5f71..f063cff178c5 100644 --- a/include/uapi/linux/nbd.h +++ b/include/uapi/linux/nbd.h @@ -38,11 +38,12 @@ enum { }; /* values for flags field */ -#define NBD_FLAG_HAS_FLAGS (1 << 0) /* nbd-server supports flags */ -#define NBD_FLAG_READ_ONLY (1 << 1) /* device is read-only */ -#define NBD_FLAG_SEND_FLUSH (1 << 2) /* can flush writeback cache */ +#define NBD_FLAG_HAS_FLAGS (1 << 0) /* nbd-server supports flags */ +#define NBD_FLAG_READ_ONLY (1 << 1) /* device is read-only */ +#define NBD_FLAG_SEND_FLUSH (1 << 2) /* can flush writeback cache */ /* there is a gap here to match userspace */ -#define NBD_FLAG_SEND_TRIM (1 << 5) /* send trim/discard */ +#define NBD_FLAG_SEND_TRIM (1 << 5) /* send trim/discard */ +#define NBD_FLAG_CAN_MULTI_CONN (1 << 7) /* Server supports multiple connections per export. */ /* userspace doesn't need the nbd_device structure */ |