> -----Original Message-----
> From: Maxime Coquelin <maxime.coque...@redhat.com>
> Sent: Tuesday, April 13, 2021 9:08 PM
> To: Jiang, Cheng1 <cheng1.ji...@intel.com>; Xia, Chenbo
> <chenbo....@intel.com>
> Cc: dev@dpdk.org; Hu, Jiayu <jiayu...@intel.com>; Yang, YvonneX
> <yvonnex.y...@intel.com>; Wang, Yinan <yinan.w...@intel.com>; Liu,
> Yong <yong....@intel.com>
> Subject: Re: [PATCH v5 2/4] vhost: add support for packed ring in async vhost
>
>
>
> On 4/13/21 1:48 PM, Jiang, Cheng1 wrote:
> > Hi Maxime,
> >
> >> -----Original Message-----
> >> From: Maxime Coquelin <maxime.coque...@redhat.com>
> >> Sent: Tuesday, April 13, 2021 4:37 PM
> >> To: Jiang, Cheng1 <cheng1.ji...@intel.com>; Xia, Chenbo
> >> <chenbo....@intel.com>
> >> Cc: dev@dpdk.org; Hu, Jiayu <jiayu...@intel.com>; Yang, YvonneX
> >> <yvonnex.y...@intel.com>; Wang, Yinan <yinan.w...@intel.com>; Liu,
> >> Yong <yong....@intel.com>
> >> Subject: Re: [PATCH v5 2/4] vhost: add support for packed ring in
> >> async vhost
> >>
> >>
> >>
> >> On 4/12/21 1:34 PM, Cheng Jiang wrote:
> >>> For now async vhost data path only supports split ring structure. In
> >>> order to make async vhost compatible with virtio 1.1 spec this patch
> >>> enables packed ring in async vhost data path.
> >>>
> >>> Signed-off-by: Cheng Jiang <cheng1.ji...@intel.com>
> >>> ---
> >>> lib/librte_vhost/rte_vhost_async.h | 1 +
> >>> lib/librte_vhost/vhost.c | 27 +-
> >>> lib/librte_vhost/vhost.h | 7 +-
> >>> lib/librte_vhost/virtio_net.c | 438
> +++++++++++++++++++++++++++--
> >>> 4 files changed, 448 insertions(+), 25 deletions(-)
> >>>
> >>> diff --git a/lib/librte_vhost/rte_vhost_async.h
> >>> b/lib/librte_vhost/rte_vhost_async.h
> >>> index c855ff875..6faa31f5a 100644
> >>> --- a/lib/librte_vhost/rte_vhost_async.h
> >>> +++ b/lib/librte_vhost/rte_vhost_async.h
> >>> @@ -89,6 +89,7 @@ struct rte_vhost_async_channel_ops { struct
> >>> async_inflight_info {
> >>> struct rte_mbuf *mbuf;
> >>> uint16_t descs; /* num of descs inflight */
> >>> + uint16_t nr_buffers; /* num of buffers inflight for packed ring */
> >>> };
> >>>
> >>> /**
> >>> diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
> >>> index a70fe01d8..8c9935c0f 100644
> >>> --- a/lib/librte_vhost/vhost.c
> >>> +++ b/lib/librte_vhost/vhost.c
> >>> @@ -342,15 +342,21 @@ vhost_free_async_mem(struct
> vhost_virtqueue
> >> *vq)
> >>> {
> >>> if (vq->async_pkts_info)
> >>> rte_free(vq->async_pkts_info);
> >>> - if (vq->async_descs_split)
> >>> + if (vq->async_buffers_packed) {
> >>> + rte_free(vq->async_buffers_packed);
> >>> + vq->async_buffers_packed = NULL;
> >>> + }
> >>> + if (vq->async_descs_split) {
> >>
> >> You can remove the check, rte_free is safe with NULL pointers.
> >> You can do the same for the other ones in this function.
> >
> > OK, it will be fixed.
> >
> >>
> >>> rte_free(vq->async_descs_split);
> >>> + vq->async_descs_split = NULL;
> >>> + }
> >>> +
> >>> if (vq->it_pool)
> >>> rte_free(vq->it_pool);
> >>> if (vq->vec_pool)
> >>> rte_free(vq->vec_pool);
> >>>
> >>> vq->async_pkts_info = NULL;
> >>> - vq->async_descs_split = NULL;
> >>> vq->it_pool = NULL;
> >>> vq->vec_pool = NULL;
> >>> }
> >>> @@ -1627,9 +1633,9 @@ int rte_vhost_async_channel_register(int vid,
> >> uint16_t queue_id,
> >>> return -1;
> >>>
> >>> /* packed queue is not supported */
> >>> - if (unlikely(vq_is_packed(dev) || !f.async_inorder)) {
> >>> + if (unlikely(!f.async_inorder)) {
> >>> VHOST_LOG_CONFIG(ERR,
> >>> - "async copy is not supported on packed queue or
> >> non-inorder mode "
> >>> + "async copy is not supported on non-inorder mode "
> >>> "(vid %d, qid: %d)\n", vid, queue_id);
> >>> return -1;
> >>> }
> >>> @@ -1667,11 +1673,18 @@ int rte_vhost_async_channel_register(int
> >>> vid,
> >> uint16_t queue_id,
> >>> vq->vec_pool = rte_malloc_socket(NULL,
> >>> VHOST_MAX_ASYNC_VEC * sizeof(struct iovec),
> >>> RTE_CACHE_LINE_SIZE, node);
> >>> - vq->async_descs_split = rte_malloc_socket(NULL,
> >>> + if (vq_is_packed(dev)) {
> >>> + vq->async_buffers_packed = rte_malloc_socket(NULL,
> >>> + vq->size * sizeof(struct vring_used_elem_packed),
> >>> + RTE_CACHE_LINE_SIZE, node);
> >>> + } else {
> >>> + vq->async_descs_split = rte_malloc_socket(NULL,
> >>> vq->size * sizeof(struct vring_used_elem),
> >>> RTE_CACHE_LINE_SIZE, node);
> >>> - if (!vq->async_descs_split || !vq->async_pkts_info ||
> >>> - !vq->it_pool || !vq->vec_pool) {
> >>> + }
> >>> +
> >>> + if (!vq->async_buffers_packed || !vq->async_descs_split ||
> >>> + !vq->async_pkts_info || !vq->it_pool || !vq->vec_pool) {
> >>> vhost_free_async_mem(vq);
> >>> VHOST_LOG_CONFIG(ERR,
> >>> "async register failed: cannot allocate
> >> memory for vq data "
> >>> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> >>> index f628714c2..fe131ae8f 100644
> >>> --- a/lib/librte_vhost/vhost.h
> >>> +++ b/lib/librte_vhost/vhost.h
> >>> @@ -201,9 +201,14 @@ struct vhost_virtqueue {
> >>> uint16_t async_pkts_idx;
> >>> uint16_t async_pkts_inflight_n;
> >>> uint16_t async_last_pkts_n;
> >>> - struct vring_used_elem *async_descs_split;
> >>> + union {
> >>> + struct vring_used_elem *async_descs_split;
> >>> + struct vring_used_elem_packed *async_buffers_packed;
> >>> + };
> >>> uint16_t async_desc_idx;
> >>> + uint16_t async_packed_buffer_idx;
> >>
> >> Don't dupplicate variable names, async_desc_idx can be reused for
> >> packed ring. Also, they are representing the same thing, why use desc
> >> in one case and buffer in the other?
> >
> > The main reason is that the unit of the packed used ring is buffer, which
> > can
> contain many desc.
> > I think using desc_idx will cause ambiguity, but if you think that I should
> reuse the desc_idx, I have no problem with that.
>
> OK, in this case please use a union not to waste memory.
Sure, I'll fix it.
>
> >>
> >>> uint16_t last_async_desc_idx;
> >>> + uint16_t last_async_buffer_idx;
> >>
> >> Same remark here.
> >>
> >>> /* vq async features */
> >>> bool async_inorder;
> >>> diff --git a/lib/librte_vhost/virtio_net.c
> >>> b/lib/librte_vhost/virtio_net.c index c43ab0093..410be9678 100644
> >>> --- a/lib/librte_vhost/virtio_net.c
> >>> +++ b/lib/librte_vhost/virtio_net.c
> >>> @@ -363,14 +363,14 @@
> >>> vhost_shadow_dequeue_single_packed_inorder(struct
> vhost_virtqueue
> >> *vq,
> >>> }
> >>>
> >>> static __rte_always_inline void
> >>> -vhost_shadow_enqueue_single_packed(struct virtio_net *dev,
> >>> - struct vhost_virtqueue *vq,
> >>> - uint32_t len[],
> >>> - uint16_t id[],
> >>> - uint16_t count[],
> >>> +vhost_shadow_enqueue_packed(struct vhost_virtqueue *vq,
> >>> + uint32_t *len,
> >>> + uint16_t *id,
> >>> + uint16_t *count,
> >>> uint16_t num_buffers)
> >>> {
> >>> uint16_t i;
> >>> +
> >>> for (i = 0; i < num_buffers; i++) {
> >>> /* enqueue shadow flush action aligned with batch num */
> >>> if (!vq->shadow_used_idx)
> >>> @@ -382,6 +382,17 @@ vhost_shadow_enqueue_single_packed(struct
> >> virtio_net *dev,
> >>> vq->shadow_aligned_idx += count[i];
> >>> vq->shadow_used_idx++;
> >>> }
> >>> +}
> >>> +
> >>> +static __rte_always_inline void
> >>> +vhost_shadow_enqueue_single_packed(struct virtio_net *dev,
> >>> + struct vhost_virtqueue *vq,
> >>> + uint32_t *len,
> >>> + uint16_t *id,
> >>> + uint16_t *count,
> >>> + uint16_t num_buffers)
> >>> +{
> >>> + vhost_shadow_enqueue_packed(vq, len, id, count, num_buffers);
> >>>
> >>> if (vq->shadow_aligned_idx >= PACKED_BATCH_SIZE) {
> >>> do_data_copy_enqueue(dev, vq);
> >>> @@ -1481,6 +1492,62 @@ shadow_ring_store(struct vhost_virtqueue
> *vq,
> >> void *shadow_ring, void *d_ring,
> >>> }
> >>> }
> >>>
> >>> +static __rte_always_inline void
> >>> +vhost_update_used_packed(struct vhost_virtqueue *vq,
> >>> + struct vring_used_elem_packed *shadow_ring,
> >>> + uint16_t count)
> >>> +{
> >>> + if (count == 0)
> >>> + return;
> >>
> >> Move this after the variables declaration.
> >
> > Sure.
> >
> >>
> >>> +
> >>> + int i;
> >>> + uint16_t used_idx = vq->last_used_idx;
> >>> + uint16_t head_idx = vq->last_used_idx;
> >>> + uint16_t head_flags = 0;
> >>> +
> >>> + /* Split loop in two to save memory barriers */
> >>> + for (i = 0; i < count; i++) {
> >>> + vq->desc_packed[used_idx].id = shadow_ring[i].id;
> >>> + vq->desc_packed[used_idx].len = shadow_ring[i].len;
> >>> +
> >>> + used_idx += shadow_ring[i].count;
> >>> + if (used_idx >= vq->size)
> >>> + used_idx -= vq->size;
> >>> + }
> >>> +
> >>> + /* The ordering for storing desc flags needs to be enforced. */
> >>> + rte_atomic_thread_fence(__ATOMIC_RELEASE);
> >>> +
> >>> + for (i = 0; i < count; i++) {
> >>> + uint16_t flags;
> >>> +
> >>> + if (vq->shadow_used_packed[i].len)
> >>> + flags = VRING_DESC_F_WRITE;
> >>> + else
> >>> + flags = 0;
> >>> +
> >>> + if (vq->used_wrap_counter) {
> >>> + flags |= VRING_DESC_F_USED;
> >>> + flags |= VRING_DESC_F_AVAIL;
> >>> + } else {
> >>> + flags &= ~VRING_DESC_F_USED;
> >>> + flags &= ~VRING_DESC_F_AVAIL;
> >>> + }
> >>> +
> >>> + if (i > 0) {
> >>> + vq->desc_packed[vq->last_used_idx].flags = flags;
> >>> +
> >>> + } else {
> >>> + head_idx = vq->last_used_idx;
> >>> + head_flags = flags;
> >>> + }
> >>> +
> >>> + vq_inc_last_used_packed(vq, shadow_ring[i].count);
> >>> + }
> >>> +
> >>> + vq->desc_packed[head_idx].flags = head_flags; }
> >>> +
> >>> static __rte_noinline uint32_t
> >>> virtio_dev_rx_async_submit_split(struct virtio_net *dev,
> >>> struct vhost_virtqueue *vq, uint16_t queue_id, @@ -1656,6
> >> +1723,294
> >>> @@ virtio_dev_rx_async_submit_split(struct virtio_net *dev,
> >>> return pkt_idx;
> >>> }
> >>>
> >>> +static __rte_always_inline int
> >>> +vhost_enqueue_async_single_packed(struct virtio_net *dev,
> >>> + struct vhost_virtqueue *vq,
> >>> + struct rte_mbuf *pkt,
> >>> + struct buf_vector *buf_vec,
> >>> + uint16_t *nr_descs,
> >>> + uint16_t *nr_buffers,
> >>> + struct vring_packed_desc *async_descs,
> >>> + struct iovec *src_iovec, struct iovec *dst_iovec,
> >>> + struct rte_vhost_iov_iter *src_it,
> >>> + struct rte_vhost_iov_iter *dst_it) {
> >>> + uint16_t nr_vec = 0;
> >>> + uint16_t avail_idx = vq->last_avail_idx;
> >>> + uint16_t max_tries, tries = 0;
> >>> + uint16_t buf_id = 0;
> >>> + uint32_t len = 0;
> >>> + uint16_t desc_count = 0;
> >>> + uint32_t size = pkt->pkt_len + sizeof(struct
> >> virtio_net_hdr_mrg_rxbuf);
> >>> + uint32_t buffer_len[vq->size];
> >>> + uint16_t buffer_buf_id[vq->size];
> >>> + uint16_t buffer_desc_count[vq->size];
> >>> + *nr_buffers = 0;
> >>> +
> >>> + if (rxvq_is_mergeable(dev))
> >>> + max_tries = vq->size - 1;
> >>> + else
> >>> + max_tries = 1;
> >>> +
> >>> + while (size > 0) {
> >>> + /*
> >>> + * if we tried all available ring items, and still
> >>> + * can't get enough buf, it means something abnormal
> >>> + * happened.
> >>> + */
> >>> + if (unlikely(++tries > max_tries))
> >>> + return -1;
> >>> +
> >>> + if (unlikely(fill_vec_buf_packed(dev, vq,
> >>> + avail_idx, &desc_count,
> >>> + buf_vec, &nr_vec,
> >>> + &buf_id, &len,
> >>> + VHOST_ACCESS_RW) < 0))
> >>> + return -1;
> >>> +
> >>> + len = RTE_MIN(len, size);
> >>> + size -= len;
> >>> +
> >>> + buffer_len[*nr_buffers] = len;
> >>> + buffer_buf_id[*nr_buffers] = buf_id;
> >>> + buffer_desc_count[*nr_buffers] = desc_count;
> >>> + *nr_buffers += 1;
> >>> +
> >>> + *nr_descs += desc_count;
> >>> + avail_idx += desc_count;
> >>> + if (avail_idx >= vq->size)
> >>> + avail_idx -= vq->size;
> >>> + }
> >>> +
> >>> + if (async_mbuf_to_desc(dev, vq, pkt, buf_vec, nr_vec, *nr_buffers,
> >>> + src_iovec, dst_iovec, src_it, dst_it) < 0)
> >>> + return -1;
> >>> + /* store descriptors for DMA */
> >>> + if (avail_idx >= *nr_descs)
> >>> + rte_memcpy(async_descs,
> >>> + &vq->desc_packed[vq->last_avail_idx],
> >>> + *nr_descs * sizeof(struct vring_packed_desc));
> >>
> >> Please add brackets for the 'if' since there are for the 'else'.
> >
> > Sure, sorry for that.
> >
> >>
> >>> + else {
> >>> + uint16_t nr_copy = vq->size - vq->last_avail_idx;
> >>> + rte_memcpy(async_descs,
> >>> + &vq->desc_packed[vq->last_avail_idx],
> >>> + nr_copy * sizeof(struct vring_packed_desc));
> >>> + rte_memcpy(async_descs + nr_copy,
> >>> + vq->desc_packed, (*nr_descs - nr_copy) *
> >>> + sizeof(struct vring_packed_desc));
> >>> + }
> >>> +
> >>> + vhost_shadow_enqueue_packed(vq, buffer_len, buffer_buf_id,
> >>> + buffer_desc_count, *nr_buffers);
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static __rte_always_inline int16_t
> >>> +virtio_dev_rx_async_single_packed(struct virtio_net *dev,
> >>> + struct vhost_virtqueue *vq,
> >>> + struct rte_mbuf *pkt,
> >>> + uint16_t *nr_descs, uint16_t *nr_buffers,
> >>> + struct vring_packed_desc *async_descs,
> >>> + struct iovec *src_iovec, struct iovec *dst_iovec,
> >>> + struct rte_vhost_iov_iter *src_it,
> >>> + struct rte_vhost_iov_iter *dst_it) {
> >>> + struct buf_vector buf_vec[BUF_VECTOR_MAX];
> >>> + *nr_descs = 0;
> >>> + *nr_buffers = 0;
> >>> +
> >>> + if (unlikely(vhost_enqueue_async_single_packed(dev, vq, pkt,
> >> buf_vec,
> >>> + nr_descs,
> >>> + nr_buffers,
> >>> + async_descs,
> >>> + src_iovec, dst_iovec,
> >>> + src_it, dst_it) < 0)) {
> >>> + VHOST_LOG_DATA(DEBUG,
> >>> + "(%d) failed to get enough desc from vring\n",
> >>> + dev->vid);
> >>> + return -1;
> >>> + }
> >>> +
> >>> + VHOST_LOG_DATA(DEBUG, "(%d) current index %d | end
> >> index %d\n",
> >>> + dev->vid, vq->last_avail_idx,
> >>> + vq->last_avail_idx + *nr_descs);
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static __rte_noinline uint32_t
> >>> +virtio_dev_rx_async_submit_packed(struct virtio_net *dev,
> >>> + struct vhost_virtqueue *vq, uint16_t queue_id,
> >>> + struct rte_mbuf **pkts, uint32_t count,
> >>> + struct rte_mbuf **comp_pkts, uint32_t *comp_count) {
> >>> + uint32_t pkt_idx = 0, pkt_burst_idx = 0;
> >>> + uint16_t async_descs_idx = 0;
> >>> + uint16_t num_buffers;
> >>> + uint16_t num_desc;
> >>> +
> >>> + struct rte_vhost_iov_iter *it_pool = vq->it_pool;
> >>> + struct iovec *vec_pool = vq->vec_pool;
> >>> + struct rte_vhost_async_desc tdes[MAX_PKT_BURST];
> >>> + struct iovec *src_iovec = vec_pool;
> >>> + struct iovec *dst_iovec = vec_pool + (VHOST_MAX_ASYNC_VEC >>
> >> 1);
> >>> + struct rte_vhost_iov_iter *src_it = it_pool;
> >>> + struct rte_vhost_iov_iter *dst_it = it_pool + 1;
> >>> + uint16_t slot_idx = 0;
> >>> + uint16_t segs_await = 0;
> >>> + uint16_t iovec_idx = 0, it_idx = 0;
> >>> + struct async_inflight_info *pkts_info = vq->async_pkts_info;
> >>> + uint32_t n_pkts = 0, pkt_err = 0;
> >>> + uint32_t num_async_pkts = 0, num_done_pkts = 0;
> >>> + struct vring_packed_desc async_descs[vq->size];
> >>> +
> >>> + rte_prefetch0(&vq->desc_packed[vq->last_avail_idx & (vq->size -
> >>> +1)]);
> >>
> >> The size of the ring is not necessarily a power of two with packed ring.
> >
> > For the size of the ring is not necessarily a power of two, so maybe I
> > can use codes like Indx % vq->size ?
> > I'm not sure if it's a good way to do that.
>
> In this case it is OK.
OK. I'll fix them in the next version.
Thanks a lot.
Cheng
>
> >>
> >>> +
> >>> + for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
> >>> + if (unlikely(virtio_dev_rx_async_single_packed(dev, vq,
> >>> + pkts[pkt_idx],
> >>> + &num_desc, &num_buffers,
> >>> +
> >> &async_descs[async_descs_idx],
> >>> + &src_iovec[iovec_idx],
> >>> + &dst_iovec[iovec_idx],
> >>> + &src_it[it_idx],
> >>> + &dst_it[it_idx]) < 0))
> >>> + break;
> >>> +
> >>> + VHOST_LOG_DATA(DEBUG, "(%d) current index %d | end
> >> index %d\n",
> >>> + dev->vid, vq->last_avail_idx,
> >>> + vq->last_avail_idx + num_desc);
> >>> +
> >>> + slot_idx = (vq->async_pkts_idx + num_async_pkts) &
> >>> + (vq->size - 1);
> >>
> >> Same here.
> >
> > Sure.
> >
> >>
> >>> + if (src_it[it_idx].count) {
> >>> + uint16_t from, to;
> >>> +
> >>> + async_descs_idx += num_desc;
> >>> + async_fill_desc(&tdes[pkt_burst_idx++],
> >> &src_it[it_idx],
> >>> + &dst_it[it_idx]);
> >>> + pkts_info[slot_idx].descs = num_desc;
> >>> + pkts_info[slot_idx].nr_buffers = num_buffers;
> >>> + pkts_info[slot_idx].mbuf = pkts[pkt_idx];
> >>> + num_async_pkts++;
> >>> + iovec_idx += src_it[it_idx].nr_segs;
> >>> + it_idx += 2;
> >>> +
> >>> + segs_await += src_it[it_idx].nr_segs;
> >>> +
> >>> + /**
> >>> + * recover shadow used ring and keep DMA-occupied
> >>> + * descriptors.
> >>> + */
> >>> + from = vq->shadow_used_idx - num_buffers;
> >>> + to = vq->async_packed_buffer_idx & (vq->size - 1);
> >>> + shadow_ring_store(vq, vq->shadow_used_packed,
> >>> + vq->async_buffers_packed,
> >>> + from, to, num_buffers,
> >>> + sizeof(struct
> >> vring_used_elem_packed));
> >>> +
> >>> + vq->async_packed_buffer_idx += num_buffers;
> >>> + vq->shadow_used_idx -= num_buffers;
> >>> + } else
> >>
> >> Brackets needed.
> >
> > Sure.
> >
> >>
> >>> + comp_pkts[num_done_pkts++] = pkts[pkt_idx];
> >>> +
> >>> + vq_inc_last_avail_packed(vq, num_desc);
> >>> +
> >>> + /*
> >>> + * conditions to trigger async device transfer:
> >>> + * - buffered packet number reaches transfer threshold
> >>> + * - unused async iov number is less than max vhost vector
> >>> + */
> >>> + if (unlikely(pkt_burst_idx >=
> >> VHOST_ASYNC_BATCH_THRESHOLD ||
> >>> + ((VHOST_MAX_ASYNC_VEC >> 1) - segs_await <
> >>> + BUF_VECTOR_MAX))) {
> >>> + n_pkts = vq->async_ops.transfer_data(dev->vid,
> >>> + queue_id, tdes, 0, pkt_burst_idx);
> >>> + iovec_idx = 0;
> >>> + it_idx = 0;
> >>> + segs_await = 0;
> >>> + vq->async_pkts_inflight_n += n_pkts;
> >>> +
> >>> + if (unlikely(n_pkts < pkt_burst_idx)) {
> >>> + /*
> >>> + * log error packets number here and do
> >> actual
> >>> + * error processing when applications poll
> >>> + * completion
> >>> + */
> >>> + pkt_err = pkt_burst_idx - n_pkts;
> >>> + pkt_burst_idx = 0;
> >>> + pkt_idx++;
> >>> + break;
> >>> + }
> >>> +
> >>> + pkt_burst_idx = 0;
> >>> + }
> >>> + }
> >>> +
> >>> + if (pkt_burst_idx) {
> >>> + n_pkts = vq->async_ops.transfer_data(dev->vid,
> >>> + queue_id, tdes, 0, pkt_burst_idx);
> >>> + vq->async_pkts_inflight_n += n_pkts;
> >>> +
> >>> + if (unlikely(n_pkts < pkt_burst_idx))
> >>> + pkt_err = pkt_burst_idx - n_pkts;
> >>> + }
> >>> +
> >>> + do_data_copy_enqueue(dev, vq);
> >>> +
> >>> + if (unlikely(pkt_err)) {
> >>> + uint16_t descs_err = 0;
> >>> + uint16_t buffers_err = 0;
> >>> +
> >>> + num_async_pkts -= pkt_err;
> >>> + pkt_idx -= pkt_err;
> >>> + /* calculate the sum of buffers and descs of DMA-error packets. */
> >>> + while (pkt_err-- > 0) {
> >>> + descs_err +=
> >>> + pkts_info[slot_idx & (vq->size - 1)].descs;
> >>
> >> The size of the ring is not necessarily a power of two with packed ring.
> >
> > Will be fixed.
> >
> >>
> >>> + buffers_err +=
> >>> + pkts_info[slot_idx & (vq->size -
> >> 1)].nr_buffers;
> >>
> >> Ditto.
> >
> > Will be fixed.
> >
> >>
> >>> + slot_idx--;
> >>> + }
> >>> +
> >>> + vq->async_packed_buffer_idx -= buffers_err;
> >>> +
> >>> + if (vq->last_avail_idx >= descs_err) {
> >>> + vq->last_avail_idx -= descs_err;
> >>> +
> >>> + rte_memcpy(&vq->desc_packed[vq->last_avail_idx],
> >>> + &async_descs[async_descs_idx - descs_err],
> >>> + descs_err * sizeof(struct
> >> vring_packed_desc));
> >>> + } else {
> >>> + uint16_t nr_copy;
> >>> +
> >>> + vq->last_avail_idx = vq->last_avail_idx + vq->size
> >>> + - descs_err;
> >>> + nr_copy = vq->size - vq->last_avail_idx;
> >>> + rte_memcpy(&vq->desc_packed[vq->last_avail_idx],
> >>> + &async_descs[async_descs_idx - descs_err],
> >>> + nr_copy * sizeof(struct vring_packed_desc));
> >>> + descs_err -= nr_copy;
> >>> + rte_memcpy(vq->desc_packed,
> >>> + &async_descs[async_descs_idx - descs_err],
> >>> + descs_err * sizeof(struct
> >> vring_packed_desc));
> >>> + vq->avail_wrap_counter ^= 1;
> >>> + }
> >>> +
> >>> + num_done_pkts = pkt_idx - num_async_pkts;
> >>> + }
> >>
> >> This error handling could be moved in a dedicated function.
> >
> > Sure, will fix it in the next version.
> >
> >>
> >>> + vq->async_pkts_idx += num_async_pkts;
> >>> + *comp_count = num_done_pkts;
> >>> +
> >>> + if (likely(vq->shadow_used_idx)) {
> >>> + vhost_flush_enqueue_shadow_packed(dev, vq);
> >>> + vhost_vring_call_packed(dev, vq);
> >>> + }
> >>> +
> >>> + return pkt_idx;
> >>> +}
> >>
> >> Above function is very big and complex, it should be possible to
> >> split it in several ones to make it maintainable.
> >
> > I think move the error handling code will make it smaller.
> >
> > Thanks.
> > Cheng
> >
> >>
> >>> +
> >>> static __rte_always_inline void
> >>> write_back_completed_descs_split(struct vhost_virtqueue *vq,
> >>> uint16_t
> >>> n_descs) { @@ -1693,12 +2048,40 @@
> >>> write_back_completed_descs_split(struct vhost_virtqueue *vq,
> >>> uint16_t
> >> n_descs)
> >>> } while (nr_left > 0);
> >>> }
> >>>
> >>> +static __rte_always_inline void
> >>> +write_back_completed_descs_packed(struct vhost_virtqueue *vq,
> >>> + uint16_t n_buffers)
> >>> +{
> >>> + uint16_t nr_left = n_buffers;
> >>> + uint16_t from, to;
> >>> +
> >>> + do {
> >>> + from = vq->last_async_buffer_idx &
> >>> + (vq->size - 1);
> >>> + to = (from + nr_left) & (vq->size - 1);
> >>
> >> The size of the ring is not necessarily a power of two with packed ring.
> >
> > Sure.
> >
> >>
> >>> + if (to > from) {
> >>> + vhost_update_used_packed(vq,
> >>> + vq->async_buffers_packed + from,
> >>> + to - from);
> >>> + vq->last_async_buffer_idx += nr_left;
> >>> + nr_left = 0;
> >>> + } else {
> >>> + vhost_update_used_packed(vq,
> >>> + vq->async_buffers_packed + from,
> >>> + vq->size - from);
> >>> + vq->last_async_buffer_idx +=
> >>> + vq->size - from;
> >>> + nr_left -= vq->size - from;
> >>> + }
> >>> + } while (nr_left > 0);
> >>> +}
> >>> +
> >>> uint16_t rte_vhost_poll_enqueue_completed(int vid, uint16_t
> queue_id,
> >>> struct rte_mbuf **pkts, uint16_t count) {
> >>> struct virtio_net *dev = get_device(vid);
> >>> struct vhost_virtqueue *vq;
> >>> - uint16_t n_pkts_cpl = 0, n_pkts_put = 0, n_descs = 0;
> >>> + uint16_t n_pkts_cpl = 0, n_pkts_put = 0, n_descs = 0, n_buffers =
> >>> +0;
> >>> uint16_t start_idx, pkts_idx, vq_size;
> >>> struct async_inflight_info *pkts_info;
> >>> uint16_t from, i;
> >>> @@ -1740,21 +2123,41 @@ uint16_t
> >> rte_vhost_poll_enqueue_completed(int vid, uint16_t queue_id,
> >>> goto done;
> >>> }
> >>>
> >>> - for (i = 0; i < n_pkts_put; i++) {
> >>> - from = (start_idx + i) & (vq_size - 1);
> >>> - n_descs += pkts_info[from].descs;
> >>> - pkts[i] = pkts_info[from].mbuf;
> >>> + if (vq_is_packed(dev)) {
> >>> + for (i = 0; i < n_pkts_put; i++) {
> >>> + from = (start_idx + i) & (vq_size - 1);
> >>
> >> Unlike split ring, packed ring size is not necessarily a power of 2.
> >
> > Sure.
> > Thanks.
> >
> >>
> >>> + n_buffers += pkts_info[from].nr_buffers;
> >>> + pkts[i] = pkts_info[from].mbuf;
> >>> + }
> >>> + } else {
> >>> + for (i = 0; i < n_pkts_put; i++) {
> >>> + from = (start_idx + i) & (vq_size - 1);
> >>> + n_descs += pkts_info[from].descs;
> >>> + pkts[i] = pkts_info[from].mbuf;
> >>> + }
> >>> }
> >>> +
> >>> vq->async_last_pkts_n = n_pkts_cpl - n_pkts_put;
> >>> vq->async_pkts_inflight_n -= n_pkts_put;
> >>>
> >>> if (likely(vq->enabled && vq->access_ok)) {
> >>> - write_back_completed_descs_split(vq, n_descs);
> >>> + if (vq_is_packed(dev)) {
> >>> + write_back_completed_descs_packed(vq,
> >> n_buffers);
> >>>
> >>> - __atomic_add_fetch(&vq->used->idx, n_descs,
> >> __ATOMIC_RELEASE);
> >>> - vhost_vring_call_split(dev, vq);
> >>> - } else
> >>> - vq->last_async_desc_idx += n_descs;
> >>> + vhost_vring_call_packed(dev, vq);
> >>> + } else {
> >>> + write_back_completed_descs_split(vq, n_descs);
> >>> +
> >>> + __atomic_add_fetch(&vq->used->idx, n_descs,
> >>> + __ATOMIC_RELEASE);
> >>> + vhost_vring_call_split(dev, vq);
> >>> + }
> >>> + } else {
> >>> + if (vq_is_packed(dev))
> >>> + vq->last_async_buffer_idx += n_buffers;
> >>> + else
> >>> + vq->last_async_desc_idx += n_descs;
> >>> + }
> >>>
> >>> done:
> >>> rte_spinlock_unlock(&vq->access_lock);
> >>> @@ -1795,9 +2198,10 @@ virtio_dev_rx_async_submit(struct virtio_net
> >> *dev, uint16_t queue_id,
> >>> if (count == 0)
> >>> goto out;
> >>>
> >>> - /* TODO: packed queue not implemented */
> >>> if (vq_is_packed(dev))
> >>> - nb_tx = 0;
> >>> + nb_tx = virtio_dev_rx_async_submit_packed(dev,
> >>> + vq, queue_id, pkts, count, comp_pkts,
> >>> + comp_count);
> >>> else
> >>> nb_tx = virtio_dev_rx_async_submit_split(dev,
> >>> vq, queue_id, pkts, count, comp_pkts,
> >>>
> >
