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| author | Josef Bacik | 2016-11-22 20:04:40 +0100 |
|---|---|---|
| committer | Jens Axboe | 2016-11-22 20:16:32 +0100 |
| commit | 9561a7ade0c205bc2ee035a2ac880478dcc1a024 (patch) | |
| tree | 3c638cde9063a2461b9767ec626b4359445c662a /include/uapi/linux/nbd.h | |
| parent | block,blkcg: use __GFP_NOWARN for best-effort allocations in blkcg (diff) | |
| download | kernel-qcow2-linux-9561a7ade0c205bc2ee035a2ac880478dcc1a024.tar.gz kernel-qcow2-linux-9561a7ade0c205bc2ee035a2ac880478dcc1a024.tar.xz kernel-qcow2-linux-9561a7ade0c205bc2ee035a2ac880478dcc1a024.zip | |
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/linux/nbd.h')
| -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 */ |