Re: [dpdk-dev] [PATCH v2 2/3] vhost: rework async feature struct
From: Maxime Coquelin <hidden>
Date: 2021-07-07 06:39:32
Hi Jiayu, On 7/7/21 1:18 PM, Jiayu Hu wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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.
quoted hunk ↗ jump to hunk
+ 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 vhostdiff --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;