> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Ouyang Changchun
> Sent: Friday, July 25, 2014 2:03 PM
> To: dev at dpdk.org
> Subject: [dpdk-dev] [PATCH v2] virtio: Support mergeable buffer in virtio PMD
>
> v2 change:
> - Resolve conflicts wiht the tip code;
> - And resolve 2 issues:
> -- fix mbuf leak when discard a uncompleted packet.
> -- refine pkt.data to point to actual payload data start point.
>
> v1 change:
> This patch supports mergeable buffer feature in DPDK based virtio PMD, which
> can
> receive jumbo frame with larger size, like 3K, 4K or even 9K.
>
> Signed-off-by: Changchun Ouyang <changchun.ouyang at intel.com>
> ---
> lib/librte_pmd_virtio/virtio_ethdev.c | 20 ++--
> lib/librte_pmd_virtio/virtio_ethdev.h | 3 +
> lib/librte_pmd_virtio/virtio_rxtx.c | 206 +++++++++++++++++++++++++++++---
> --
> 3 files changed, 194 insertions(+), 35 deletions(-)
>
> diff --git a/lib/librte_pmd_virtio/virtio_ethdev.c
> b/lib/librte_pmd_virtio/virtio_ethdev.c
> index b9f5529..535d798 100644
> --- a/lib/librte_pmd_virtio/virtio_ethdev.c
> +++ b/lib/librte_pmd_virtio/virtio_ethdev.c
> @@ -337,7 +337,7 @@ int virtio_dev_queue_setup(struct rte_eth_dev *dev,
> snprintf(vq_name, sizeof(vq_name), "port%d_tvq%d_hdrzone",
> dev->data->port_id, queue_idx);
> vq->virtio_net_hdr_mz =
> rte_memzone_reserve_aligned(vq_name,
> - vq_size * sizeof(struct virtio_net_hdr),
> + vq_size * hw->vtnet_hdr_size,
> socket_id, 0, CACHE_LINE_SIZE);
> if (vq->virtio_net_hdr_mz == NULL) {
> rte_free(vq);
> @@ -346,7 +346,7 @@ int virtio_dev_queue_setup(struct rte_eth_dev *dev,
> vq->virtio_net_hdr_mem =
> vq->virtio_net_hdr_mz->phys_addr;
> memset(vq->virtio_net_hdr_mz->addr, 0,
> - vq_size * sizeof(struct virtio_net_hdr));
> + vq_size * hw->vtnet_hdr_size);
> } else if (queue_type == VTNET_CQ) {
> /* Allocate a page for control vq command, data and status */
> snprintf(vq_name, sizeof(vq_name), "port%d_cvq_hdrzone",
> @@ -571,9 +571,6 @@ virtio_negotiate_features(struct virtio_hw *hw)
> mask |= VIRTIO_NET_F_GUEST_TSO4 | VIRTIO_NET_F_GUEST_TSO6 |
> VIRTIO_NET_F_GUEST_ECN;
> mask |= VTNET_LRO_FEATURES;
>
> - /* rx_mbuf should not be in multiple merged segments */
> - mask |= VIRTIO_NET_F_MRG_RXBUF;
> -
> /* not negotiating INDIRECT descriptor table support */
> mask |= VIRTIO_RING_F_INDIRECT_DESC;
>
> @@ -746,7 +743,6 @@ eth_virtio_dev_init(__rte_unused struct eth_driver
> *eth_drv,
> }
>
> eth_dev->dev_ops = &virtio_eth_dev_ops;
> - eth_dev->rx_pkt_burst = &virtio_recv_pkts;
> eth_dev->tx_pkt_burst = &virtio_xmit_pkts;
>
> if (rte_eal_process_type() == RTE_PROC_SECONDARY)
> @@ -801,10 +797,13 @@ eth_virtio_dev_init(__rte_unused struct eth_driver
> *eth_drv,
> virtio_negotiate_features(hw);
>
> /* Setting up rx_header size for the device */
> - if (vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF))
> + if (vtpci_with_feature(hw, VIRTIO_NET_F_MRG_RXBUF)) {
> + eth_dev->rx_pkt_burst = &virtio_recv_mergeable_pkts;
> hw->vtnet_hdr_size = sizeof(struct virtio_net_hdr_mrg_rxbuf);
> - else
> + } else {
> + eth_dev->rx_pkt_burst = &virtio_recv_pkts;
> hw->vtnet_hdr_size = sizeof(struct virtio_net_hdr);
> + }
>
> /* Allocate memory for storing MAC addresses */
> eth_dev->data->mac_addrs = rte_zmalloc("virtio", ETHER_ADDR_LEN,
> 0);
> @@ -1009,7 +1008,7 @@ static void virtio_dev_free_mbufs(struct rte_eth_dev
> *dev)
>
> while ((buf = (struct rte_mbuf *)virtqueue_detatch_unused(
> dev->data->rx_queues[i])) != NULL) {
> - rte_pktmbuf_free_seg(buf);
> + rte_pktmbuf_free(buf);
> mbuf_num++;
> }
>
> @@ -1028,7 +1027,8 @@ static void virtio_dev_free_mbufs(struct rte_eth_dev
> *dev)
> mbuf_num = 0;
> while ((buf = (struct rte_mbuf *)virtqueue_detatch_unused(
> dev->data->tx_queues[i])) != NULL) {
> - rte_pktmbuf_free_seg(buf);
> + rte_pktmbuf_free(buf);
> +
> mbuf_num++;
> }
>
> diff --git a/lib/librte_pmd_virtio/virtio_ethdev.h
> b/lib/librte_pmd_virtio/virtio_ethdev.h
> index 858e644..d2e1eed 100644
> --- a/lib/librte_pmd_virtio/virtio_ethdev.h
> +++ b/lib/librte_pmd_virtio/virtio_ethdev.h
> @@ -104,6 +104,9 @@ int virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
> uint16_t tx_queue_id,
> uint16_t virtio_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts,
> uint16_t nb_pkts);
>
> +uint16_t virtio_recv_mergeable_pkts(void *rx_queue, struct rte_mbuf
> **rx_pkts,
> + uint16_t nb_pkts);
> +
> uint16_t virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
> uint16_t nb_pkts);
>
> diff --git a/lib/librte_pmd_virtio/virtio_rxtx.c
> b/lib/librte_pmd_virtio/virtio_rxtx.c
> index fcd8bd1..3d81b34 100644
> --- a/lib/librte_pmd_virtio/virtio_rxtx.c
> +++ b/lib/librte_pmd_virtio/virtio_rxtx.c
> @@ -146,6 +146,7 @@ static inline int
> virtqueue_enqueue_recv_refill(struct virtqueue *vq, struct rte_mbuf *cookie)
> {
> struct vq_desc_extra *dxp;
> + struct virtio_hw *hw = vq->hw;
> struct vring_desc *start_dp;
> uint16_t needed = 1;
> uint16_t head_idx, idx;
> @@ -165,9 +166,11 @@ virtqueue_enqueue_recv_refill(struct virtqueue *vq,
> struct rte_mbuf *cookie)
> dxp->ndescs = needed;
>
> start_dp = vq->vq_ring.desc;
> - start_dp[idx].addr =
> - (uint64_t) (cookie->buf_physaddr + RTE_PKTMBUF_HEADROOM
> - sizeof(struct virtio_net_hdr));
> - start_dp[idx].len = cookie->buf_len - RTE_PKTMBUF_HEADROOM +
> sizeof(struct virtio_net_hdr);
> + start_dp[idx].addr =
> + (uint64_t)(cookie->buf_physaddr + RTE_PKTMBUF_HEADROOM
> + - hw->vtnet_hdr_size);
> + start_dp[idx].len =
> + cookie->buf_len - RTE_PKTMBUF_HEADROOM + hw-
> >vtnet_hdr_size;
> start_dp[idx].flags = VRING_DESC_F_WRITE;
> idx = start_dp[idx].next;
> vq->vq_desc_head_idx = idx;
> @@ -184,8 +187,10 @@ virtqueue_enqueue_xmit(struct virtqueue *txvq, struct
> rte_mbuf *cookie)
> {
> struct vq_desc_extra *dxp;
> struct vring_desc *start_dp;
> - uint16_t needed = 2;
> + uint16_t seg_num = cookie->pkt.nb_segs;
> + uint16_t needed = 1 + seg_num;
> uint16_t head_idx, idx;
> + uint16_t head_size = txvq->hw->vtnet_hdr_size;
>
> if (unlikely(txvq->vq_free_cnt == 0))
> return -ENOSPC;
> @@ -198,19 +203,25 @@ virtqueue_enqueue_xmit(struct virtqueue *txvq,
> struct rte_mbuf *cookie)
> idx = head_idx;
> dxp = &txvq->vq_descx[idx];
> if (dxp->cookie != NULL)
> - rte_pktmbuf_free_seg(dxp->cookie);
> + rte_pktmbuf_free(dxp->cookie);
> dxp->cookie = (void *)cookie;
> dxp->ndescs = needed;
>
> start_dp = txvq->vq_ring.desc;
> - start_dp[idx].addr =
> - txvq->virtio_net_hdr_mem + idx * sizeof(struct virtio_net_hdr);
> - start_dp[idx].len = sizeof(struct virtio_net_hdr);
> + start_dp[idx].addr =
> + txvq->virtio_net_hdr_mem + idx * head_size;
> + start_dp[idx].len = (uint32_t)head_size;
> start_dp[idx].flags = VRING_DESC_F_NEXT;
> - idx = start_dp[idx].next;
> - start_dp[idx].addr = RTE_MBUF_DATA_DMA_ADDR(cookie);
> - start_dp[idx].len = cookie->pkt.data_len;
> - start_dp[idx].flags = 0;
> +
> + for (; ((seg_num > 0) && (cookie != NULL)); seg_num--) {
> + idx = start_dp[idx].next;
> + start_dp[idx].addr = RTE_MBUF_DATA_DMA_ADDR(cookie);
> + start_dp[idx].len = cookie->pkt.data_len;
> + start_dp[idx].flags = VRING_DESC_F_NEXT;
> + cookie = cookie->pkt.next;
> + }
> +
> + start_dp[idx].flags &= ~VRING_DESC_F_NEXT;
> idx = start_dp[idx].next;
> txvq->vq_desc_head_idx = idx;
> if (txvq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END)
> @@ -284,7 +295,7 @@ virtio_dev_vring_start(struct virtqueue *vq, int
> queue_type)
> error = virtqueue_enqueue_recv_refill(vq, m);
>
> if (error) {
> - rte_pktmbuf_free_seg(m);
> + rte_pktmbuf_free(m);
> break;
> }
> nbufs++;
> @@ -423,7 +434,7 @@ virtio_discard_rxbuf(struct virtqueue *vq, struct
> rte_mbuf *m)
> error = virtqueue_enqueue_recv_refill(vq, m);
> if (unlikely(error)) {
> RTE_LOG(ERR, PMD, "cannot requeue discarded mbuf");
> - rte_pktmbuf_free_seg(m);
> + rte_pktmbuf_free(m);
> }
> }
>
> @@ -471,17 +482,158 @@ virtio_recv_pkts(void *rx_queue, struct rte_mbuf
> **rx_pkts, uint16_t nb_pkts)
>
> rxm->pkt.in_port = rxvq->port_id;
> rxm->pkt.data = (char *)rxm->buf_addr +
> RTE_PKTMBUF_HEADROOM;
> +
> rxm->pkt.nb_segs = 1;
> rxm->pkt.next = NULL;
> - rxm->pkt.pkt_len = (uint32_t)(len[i]
> - - sizeof(struct virtio_net_hdr));
> - rxm->pkt.data_len = (uint16_t)(len[i]
> - - sizeof(struct virtio_net_hdr));
> + rxm->pkt.pkt_len = (uint32_t)(len[i] - hw->vtnet_hdr_size);
> + rxm->pkt.data_len = (uint16_t)(len[i] - hw->vtnet_hdr_size);
>
> VIRTIO_DUMP_PACKET(rxm, rxm->pkt.data_len);
>
> rx_pkts[nb_rx++] = rxm;
> - rxvq->bytes += len[i] - sizeof(struct virtio_net_hdr);
> + rxvq->bytes += rx_pkts[nb_rx - 1]->pkt.pkt_len;
> + }
> +
> + rxvq->packets += nb_rx;
> +
> + /* Allocate new mbuf for the used descriptor */
> + error = ENOSPC;
> + while (likely(!virtqueue_full(rxvq))) {
> + new_mbuf = rte_rxmbuf_alloc(rxvq->mpool);
> + if (unlikely(new_mbuf == NULL)) {
> + struct rte_eth_dev *dev
> + = &rte_eth_devices[rxvq->port_id];
> + dev->data->rx_mbuf_alloc_failed++;
> + break;
> + }
> + error = virtqueue_enqueue_recv_refill(rxvq, new_mbuf);
> + if (unlikely(error)) {
> + rte_pktmbuf_free(new_mbuf);
> + break;
> + }
> + nb_enqueued++;
> + }
> +
> + if (likely(nb_enqueued)) {
> + if (unlikely(virtqueue_kick_prepare(rxvq))) {
> + virtqueue_notify(rxvq);
> + PMD_RX_LOG(DEBUG, "Notified\n");
> + }
> + }
> +
> + vq_update_avail_idx(rxvq);
> +
> + return nb_rx;
> +}
> +
> +uint16_t
> +virtio_recv_mergeable_pkts(void *rx_queue,
> + struct rte_mbuf **rx_pkts,
> + uint16_t nb_pkts)
> +{
> + struct virtqueue *rxvq = rx_queue;
> + struct virtio_hw *hw = rxvq->hw;
> + struct rte_mbuf *rxm, *new_mbuf;
> + uint16_t nb_used, num, nb_rx = 0;
> + uint32_t len[VIRTIO_MBUF_BURST_SZ];
> + struct rte_mbuf *rcv_pkts[VIRTIO_MBUF_BURST_SZ];
> + struct rte_mbuf *prev;
> + int error;
> + uint32_t i = 0, nb_enqueued = 0;
> + uint32_t seg_num = 0;
> + uint16_t extra_idx = 0;
> +
> + nb_used = VIRTQUEUE_NUSED(rxvq);
> +
> + rmb();
> +
> + if (nb_used == 0)
> + return 0;
> +
> + while (i < nb_used) {
> + struct virtio_net_hdr_mrg_rxbuf *header;
> + char *head_ptr;
> +
> + if (nb_rx >= nb_pkts)
> + break;
> +
> + num = virtqueue_dequeue_burst_rx(rxvq, rcv_pkts, len, 1);
> + i += num;
> +
> + PMD_RX_LOG(DEBUG, "used:%d dequeue:%d\n", nb_used,
> num);
> + PMD_RX_LOG(DEBUG, "packet len:%d\n", len[i]);
> +
> + rxm = rcv_pkts[0];
> + extra_idx = 0;
> +
> + if (unlikely(len[0]
> + < (uint32_t)hw->vtnet_hdr_size + ETHER_HDR_LEN))
> {
> + PMD_RX_LOG(ERR, "Packet drop\n");
> + nb_enqueued++;
> + virtio_discard_rxbuf(rxvq, rxm);
> + rxvq->errors++;
> + continue;
> + }
> +
> + head_ptr = (char *)rxm->pkt.data;
> + head_ptr -= hw->vtnet_hdr_size;
> + header = (struct virtio_net_hdr_mrg_rxbuf *)head_ptr;
> + seg_num = header->num_buffers;
> +
> + if (seg_num == 0)
> + seg_num = 1;
> +
> + rxm->pkt.data = (char *)rxm->buf_addr +
> RTE_PKTMBUF_HEADROOM;
> + rxm->pkt.nb_segs = seg_num;
> + rxm->pkt.next = NULL;
> + rxm->pkt.pkt_len = (uint32_t)(len[0] - hw->vtnet_hdr_size);
> + rxm->pkt.data_len = (uint16_t)(len[0] - hw->vtnet_hdr_size);
> +
> + rxm->pkt.in_port = rxvq->port_id;
> + rx_pkts[nb_rx] = rxm;
> +
> + prev = rxm;
> +
> + VIRTIO_DUMP_PACKET(rxm, rxm->pkt.data_len);
Here it might cause segmentation fault when debug is enabled.
> +
> + /*
> + * Get extra segments for current uncompleted packet.
> + */
> + if (VIRTQUEUE_NUSED(rxvq) >= seg_num - 1) {
> + uint32_t rx_num = virtqueue_dequeue_burst_rx(rxvq,
> + rcv_pkts, len, seg_num - 1);
> + i += rx_num;
> + } else {
> + PMD_RX_LOG(ERR, "No enough segments for
> packet.\n");
> + nb_enqueued++;
> + virtio_discard_rxbuf(rxvq, rxm);
> + rxvq->errors++;
> + break;
Here we should figure out if virtio net spec specify the behavior. If the
backend wants to en-queue a merge able packet, but there isn't enough available
descriptors, could it do it in a non-atomic way, i.e., firstly transfer some of
them, update the used->idx and later transfer the rest of them?
If that is the case, the handling here will cause the content of next segment
later en-queued to be treated as virtio merge-able header.
> + }
> +
> + while (extra_idx < seg_num - 1) {
> + rxm = rcv_pkts[extra_idx];
> +
> + rxm->pkt.data =
> + (char *)rxm->buf_addr +
> RTE_PKTMBUF_HEADROOM
> + - hw->vtnet_hdr_size;
> + rxm->pkt.next = NULL;
> + rxm->pkt.pkt_len = (uint32_t)(len[extra_idx]);
> + rxm->pkt.data_len = (uint16_t)(len[extra_idx]);
> +
> + if (prev)
> + prev->pkt.next = rxm;
> +
> + prev = rxm;
> + rx_pkts[nb_rx]->pkt.pkt_len += rxm->pkt.pkt_len;
> +
> + extra_idx++;
> +
> + VIRTIO_DUMP_PACKET(rxm, rxm->pkt.data_len);
> + };
> +
> + rxvq->bytes += rx_pkts[nb_rx]->pkt.pkt_len;
> + nb_rx++;
> }
>
> rxvq->packets += nb_rx;
> @@ -498,11 +650,12 @@ virtio_recv_pkts(void *rx_queue, struct rte_mbuf
> **rx_pkts, uint16_t nb_pkts)
> }
> error = virtqueue_enqueue_recv_refill(rxvq, new_mbuf);
> if (unlikely(error)) {
> - rte_pktmbuf_free_seg(new_mbuf);
> + rte_pktmbuf_free(new_mbuf);
> break;
> }
> nb_enqueued++;
> }
> +
> if (likely(nb_enqueued)) {
> if (unlikely(virtqueue_kick_prepare(rxvq))) {
> virtqueue_notify(rxvq);
> @@ -536,12 +689,15 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf
> **tx_pkts, uint16_t nb_pkts)
> num = (uint16_t)(likely(nb_used < VIRTIO_MBUF_BURST_SZ) ? nb_used :
> VIRTIO_MBUF_BURST_SZ);
>
> while (nb_tx < nb_pkts) {
> - if (virtqueue_full(txvq) && num) {
> - virtqueue_dequeue_pkt_tx(txvq);
> - num--;
> + int need = tx_pkts[nb_tx]->pkt.nb_segs - txvq->vq_free_cnt;
> + if ((need > 0) && (num > 0)) {
> + do {
> + virtqueue_dequeue_pkt_tx(txvq);
> + num--;
> + } while (num > 0);
> }
>
> - if (!virtqueue_full(txvq)) {
> + if (tx_pkts[nb_tx]->pkt.nb_segs <= txvq->vq_free_cnt) {
> txm = tx_pkts[nb_tx];
> /* Enqueue Packet buffers */
> error = virtqueue_enqueue_xmit(txvq, txm);
> @@ -555,7 +711,7 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf
> **tx_pkts, uint16_t nb_pkts)
> break;
> }
> nb_tx++;
> - txvq->bytes += txm->pkt.data_len;
> + txvq->bytes += txm->pkt.pkt_len;
> } else {
> PMD_TX_LOG(ERR, "No free tx descriptors to transmit");
> break;
> --
> 1.8.4.2
