Hi Jiayu,
On 7/7/21 1:18 PM, Jiayu Hu wrote:
> No need to use bitfields in the structure rte_vhost_async_features.
> This patch reworks the structure to improve code readability. In
> addition, add preserved padding fields on the structure for future
> usage.
>
> Signed-off-by: Jiayu Hu <jiayu...@intel.com>
> ---
> examples/vhost/main.c | 4 ++--
> lib/vhost/rte_vhost_async.h | 24 ++++++++----------------
> lib/vhost/vhost.c | 13 +++++--------
> 3 files changed, 15 insertions(+), 26 deletions(-)
>
> diff --git a/examples/vhost/main.c b/examples/vhost/main.c
> index d2179ea..ec1a5b4 100644
> --- a/examples/vhost/main.c
> +++ b/examples/vhost/main.c
> @@ -1468,7 +1468,7 @@ new_device(int vid)
> vid, vdev->coreid);
>
> if (async_vhost_driver) {
> - struct rte_vhost_async_features f;
> + struct rte_vhost_async_features f = {0};
> struct rte_vhost_async_channel_ops channel_ops;
>
> if (dma_type != NULL && strncmp(dma_type, "ioat", 4) == 0) {
> @@ -1480,7 +1480,7 @@ new_device(int vid)
> f.async_threshold = 256;
>
> return rte_vhost_async_channel_register(vid, VIRTIO_RXQ,
> - f.intval, &channel_ops);
> + f, &channel_ops);
> }
> }
>
> diff --git a/lib/vhost/rte_vhost_async.h b/lib/vhost/rte_vhost_async.h
> index 6faa31f..12c6962 100644
> --- a/lib/vhost/rte_vhost_async.h
> +++ b/lib/vhost/rte_vhost_async.h
> @@ -93,18 +93,13 @@ struct async_inflight_info {
> };
>
> /**
> - * dma channel feature bit definition
> + * dma channel features
> */
> struct rte_vhost_async_features {
Give the struct also contains config/tuning stuff, I don't think
rte_vhost_async_features is a good name, maybe rte_vhost_async_config?
> - union {
> - uint32_t intval;
> - struct {
> - uint32_t async_inorder:1;
> - uint32_t resvd_0:15;
> - uint32_t async_threshold:12;
> - uint32_t resvd_1:4;
> - };
> - };
> + uint32_t async_threshold;
> + uint32_t resvd_0[13];
That's a lot of padding! I hope the application won't have to use that
much to configure the async feature one day :)
> + uint8_t async_inorder;
I would prefer a uint32_t features bitfield for consistency with Vhost
library, with enums for the features definition.
> + uint8_t resvd_1[7];
> };
>
> /**
> @@ -115,11 +110,7 @@ struct rte_vhost_async_features {
> * @param queue_id
> * vhost queue id async channel to be attached to
> * @param features
> - * DMA channel feature bit
> - * b0 : DMA supports inorder data transfer
> - * b1 - b15: reserved
> - * b16 - b27: Packet length threshold for DMA transfer
> - * b28 - b31: reserved
> + * DMA channel feature structure
> * @param ops
> * DMA operation callbacks
> * @return
> @@ -127,7 +118,8 @@ struct rte_vhost_async_features {
> */
> __rte_experimental
> int rte_vhost_async_channel_register(int vid, uint16_t queue_id,
> - uint32_t features, struct rte_vhost_async_channel_ops *ops);
> + struct rte_vhost_async_features features,
> + struct rte_vhost_async_channel_ops *ops);
>
> /**
> * unregister a dma channel for vhost
> diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
> index 53a470f..835aad8 100644
> --- a/lib/vhost/vhost.c
> +++ b/lib/vhost/vhost.c
> @@ -1620,18 +1620,15 @@ int rte_vhost_extern_callback_register(int vid,
> }
>
> int rte_vhost_async_channel_register(int vid, uint16_t queue_id,
> - uint32_t features,
> - struct rte_vhost_async_channel_ops *ops)
> + struct rte_vhost_async_features features,
> + struct rte_vhost_async_channel_ops *ops)
> {
> struct vhost_virtqueue *vq;
> struct virtio_net *dev = get_device(vid);
> - struct rte_vhost_async_features f;
>
> if (dev == NULL || ops == NULL)
> return -1;
>
> - f.intval = features;
> -
> if (queue_id >= VHOST_MAX_VRING)
> return -1;
>
> @@ -1640,7 +1637,7 @@ int rte_vhost_async_channel_register(int vid, uint16_t
> queue_id,
> if (unlikely(vq == NULL || !dev->async_copy))
> return -1;
>
> - if (unlikely(!f.async_inorder)) {
> + if (unlikely(!features.async_inorder)) {
> VHOST_LOG_CONFIG(ERR,
> "async copy is not supported on non-inorder mode "
> "(vid %d, qid: %d)\n", vid, queue_id);
> @@ -1720,8 +1717,8 @@ int rte_vhost_async_channel_register(int vid, uint16_t
> queue_id,
> vq->async_ops.check_completed_copies = ops->check_completed_copies;
> vq->async_ops.transfer_data = ops->transfer_data;
>
> - vq->async_inorder = f.async_inorder;
> - vq->async_threshold = f.async_threshold;
> + vq->async_inorder = features.async_inorder;
> + vq->async_threshold = features.async_threshold;
>
> vq->async_registered = true;
>
>
