On Thu, Jun 26, 2014 at 05:41:47PM +0800, Ming Lei wrote:
> Current virtio-blk spec only supports one virtual queue for transfering
> data between VM and host, and inside VM all kinds of operations on
> the virtual queue needs to hold one lock, so cause below problems:
>
> - bad scalability
> - bad throughput
>
> This patch requests to introduce feature of VIRTIO_BLK_F_MQ
> so that more than one virtual queues can be used to virtio-blk
> device, then above problems can be solved or eased.
>
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
> include/uapi/linux/virtio_blk.h | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/include/uapi/linux/virtio_blk.h b/include/uapi/linux/virtio_blk.h
> index 6d8e61c..9ad67b2 100644
> --- a/include/uapi/linux/virtio_blk.h
> +++ b/include/uapi/linux/virtio_blk.h
> @@ -40,6 +40,7 @@
> #define VIRTIO_BLK_F_WCE 9 /* Writeback mode enabled after reset */
> #define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */
> #define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */
> +#define VIRTIO_BLK_F_MQ 12 /* support more than one vq */
>
> #ifndef __KERNEL__
> /* Old (deprecated) name for VIRTIO_BLK_F_WCE. */
> @@ -77,6 +78,10 @@ struct virtio_blk_config {
>
> /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
> __u8 wce;
> + __u8 unused;
> +
> + /* number of vqs, only available when VIRTIO_BLK_F_MQ is set */
> + __u16 num_queues;
> } __attribute__((packed));
>
> /*
> --
> 1.7.9.5
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