> -----Original Message-----
> From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Chenxu Di
> Sent: Tuesday, December 24, 2019 10:39 AM
> To: dev@dpdk.org
> Cc: Yang, Qiming <qiming.y...@intel.com>; Di, ChenxuX
> <chenxux...@intel.com>
> Subject: [dpdk-dev] [PATCH v4 2/5] net/i40e: cleanup Tx buffers
>
> Add support to the i40e driver for the API rte_eth_tx_done_cleanup to force
> free consumed buffers on Tx ring.
>
> Signed-off-by: Chenxu Di <chenxux...@intel.com>
> ---
> drivers/net/i40e/i40e_ethdev.c | 1 +
> drivers/net/i40e/i40e_ethdev_vf.c | 1 +
> drivers/net/i40e/i40e_rxtx.c | 122 ++++++++++++++++++++++++++++++
> drivers/net/i40e/i40e_rxtx.h | 1 +
> 4 files changed, 125 insertions(+)
>
> diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
> index 5999c964b..fad47a942 100644
> --- a/drivers/net/i40e/i40e_ethdev.c
> +++ b/drivers/net/i40e/i40e_ethdev.c
> @@ -522,6 +522,7 @@ static const struct eth_dev_ops i40e_eth_dev_ops = {
> .mac_addr_set = i40e_set_default_mac_addr,
> .mtu_set = i40e_dev_mtu_set,
> .tm_ops_get = i40e_tm_ops_get,
> + .tx_done_cleanup = i40e_tx_done_cleanup,
> };
>
> /* store statistics names and its offset in stats structure */ diff --git
> a/drivers/net/i40e/i40e_ethdev_vf.c b/drivers/net/i40e/i40e_ethdev_vf.c
> index 5dba0928b..0ca5417d7 100644
> --- a/drivers/net/i40e/i40e_ethdev_vf.c
> +++ b/drivers/net/i40e/i40e_ethdev_vf.c
> @@ -215,6 +215,7 @@ static const struct eth_dev_ops i40evf_eth_dev_ops = {
> .rss_hash_conf_get = i40evf_dev_rss_hash_conf_get,
> .mtu_set = i40evf_dev_mtu_set,
> .mac_addr_set = i40evf_set_default_mac_addr,
> + .tx_done_cleanup = i40e_tx_done_cleanup,
> };
>
> /*
> diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c index
> 17dc8c78f..e75733b8e 100644
> --- a/drivers/net/i40e/i40e_rxtx.c
> +++ b/drivers/net/i40e/i40e_rxtx.c
> @@ -2455,6 +2455,128 @@ i40e_tx_queue_release_mbufs(struct
> i40e_tx_queue *txq)
> }
> }
>
> +int i40e_tx_done_cleanup(void *q, uint32_t free_cnt) {
> + struct i40e_tx_queue *txq = (struct i40e_tx_queue *)q;
> + struct i40e_tx_entry *sw_ring;
> + volatile struct i40e_tx_desc *txr;
> + uint16_t tx_first; /* First segment analyzed. */
> + uint16_t tx_id; /* Current segment being processed. */
> + uint16_t tx_last; /* Last segment in the current packet. */
> + uint16_t tx_next; /* First segment of the next packet. */
> + int count;
> +
> + if (txq == NULL)
> + return -ENODEV;
> +
> + count = 0;
> + sw_ring = txq->sw_ring;
> + txr = txq->tx_ring;
> +
> + /*
> + * tx_tail is the last sent packet on the sw_ring. Goto the end
> + * of that packet (the last segment in the packet chain) and
> + * then the next segment will be the start of the oldest segment
> + * in the sw_ring. This is the first packet that will be
> + * attempted to be freed.
> + */
> +
> + /* Get last segment in most recently added packet. */
> + tx_first = sw_ring[txq->tx_tail].last_id;
Should be tx_last more readable here? And then tx_first =
sw_ring[tx_last].next_id?
> +
> + /* Get the next segment, which is the oldest segment in ring. */
> + tx_first = sw_ring[tx_first].next_id;
> +
> + /* Set the current index to the first. */
> + tx_id = tx_first;
> +
> + /*
> + * Loop through each packet. For each packet, verify that an
> + * mbuf exists and that the last segment is free. If so, free
> + * it and move on.
> + */
> + while (1) {
> + tx_last = sw_ring[tx_id].last_id;
> +
> + if (sw_ring[tx_last].mbuf) {
> + if ((txr[tx_last].cmd_type_offset_bsz &
> +
> rte_cpu_to_le_64(I40E_TXD_QW1_DTYPE_MASK)) !=
Is the logic reversed? '!=' means the mbuf is still in use.
> +
> rte_cpu_to_le_64(I40E_TX_DESC_DTYPE_DESC_DONE)) {
> + /*
> + * Increment the number of packets
> + * freed.
> + */
> + count++;
Should 'count++' be after free mbuf?
> +
> + /* Get the start of the next packet. */
> + tx_next = sw_ring[tx_last].next_id;
> +
> + /*
> + * Loop through all segments in a
> + * packet.
> + */
> + do {
> +
> rte_pktmbuf_free_seg(sw_ring[tx_id].mbuf);
> + sw_ring[tx_id].mbuf = NULL;
> + sw_ring[tx_id].last_id = tx_id;
> +
> + /* Move to next segemnt. */
Typo: segemnt -> segment
> + tx_id = sw_ring[tx_id].next_id;
> +
> + } while (tx_id != tx_next);
> +
> + if (unlikely(count == (int)free_cnt))
> + break;
> + } else {
> + /*
> + * mbuf still in use, nothing left to
> + * free.
> + */
> + break;
> + }
> + } else {
> + /*
> + * There are multiple reasons to be here:
> + * 1) All the packets on the ring have been
> + * freed - tx_id is equal to tx_first
> + * and some packets have been freed.
> + * - Done, exit
> + * 2) Interfaces has not sent a rings worth of
> + * packets yet, so the segment after tail is
> + * still empty. Or a previous call to this
> + * function freed some of the segments but
> + * not all so there is a hole in the list.
> + * Hopefully this is a rare case.
> + * - Walk the list and find the next mbuf. If
> + * there isn't one, then done.
> + */
> + if (likely(tx_id == tx_first && count != 0))
> + break;
> +
> + /*
> + * Walk the list and find the next mbuf, if any.
> + */
> + do {
> + /* Move to next segemnt. */
Typo: segemnt -> segment
> + tx_id = sw_ring[tx_id].next_id;
> +
> + if (sw_ring[tx_id].mbuf)
> + break;
> +
> + } while (tx_id != tx_first);
> +
> + /*
> + * Determine why previous loop bailed. If there
> + * is not an mbuf, done.
> + */
> + if (sw_ring[tx_id].mbuf == NULL)
> + break;
> + }
> + }
> +
> + return count;
> +}
> +
> void
> i40e_reset_tx_queue(struct i40e_tx_queue *txq) { diff --git
> a/drivers/net/i40e/i40e_rxtx.h b/drivers/net/i40e/i40e_rxtx.h index
> 2106bb355..8f11f011a 100644
> --- a/drivers/net/i40e/i40e_rxtx.h
> +++ b/drivers/net/i40e/i40e_rxtx.h
> @@ -212,6 +212,7 @@ void i40e_dev_free_queues(struct rte_eth_dev *dev);
> void i40e_reset_rx_queue(struct i40e_rx_queue *rxq); void
> i40e_reset_tx_queue(struct i40e_tx_queue *txq); void
> i40e_tx_queue_release_mbufs(struct i40e_tx_queue *txq);
> +int i40e_tx_done_cleanup(void *txq, uint32_t free_cnt);
> int i40e_alloc_rx_queue_mbufs(struct i40e_rx_queue *rxq); void
> i40e_rx_queue_release_mbufs(struct i40e_rx_queue *rxq);
>
> --
> 2.17.1
