On Mon, 30 Jun 2025 15:28:00 +0530
Gagandeep Singh <g.si...@nxp.com> wrote:
> This patch adds support for software taildrop on ordered queues
> in the DPAA2 driver.
> It also enables congestion notification by default on
> traffic management (TM) queues, which is a prerequisite for
> software taildrop functionality.
>
> Signed-off-by: Gagandeep Singh <g.si...@nxp.com>
> ---
> doc/guides/rel_notes/release_25_07.rst | 1 +
> drivers/net/dpaa2/dpaa2_rxtx.c | 24 ++++++++++-
> drivers/net/dpaa2/dpaa2_tm.c | 60 +++++++++++++-------------
> 3 files changed, 53 insertions(+), 32 deletions(-)
>
> diff --git a/doc/guides/rel_notes/release_25_07.rst
> b/doc/guides/rel_notes/release_25_07.rst
> index 53a1c8756d..dd8bc74946 100644
> --- a/doc/guides/rel_notes/release_25_07.rst
> +++ b/doc/guides/rel_notes/release_25_07.rst
> @@ -163,6 +163,7 @@ New Features
> * **Updated DPAA2 ethernet driver.**
>
> * Added DPBP APIs for setting mempool depletion thresholds.
> + * Enabled software taildrop for ordered queues.
>
> Removed Items
> -------------
> diff --git a/drivers/net/dpaa2/dpaa2_rxtx.c b/drivers/net/dpaa2/dpaa2_rxtx.c
> index 67d065bb7c..dce1da80bb 100644
> --- a/drivers/net/dpaa2/dpaa2_rxtx.c
> +++ b/drivers/net/dpaa2/dpaa2_rxtx.c
> @@ -1800,8 +1800,11 @@ dpaa2_dev_tx_ordered(void *queue, struct rte_mbuf
> **bufs, uint16_t nb_pkts)
> while (qbman_result_SCN_state(dpaa2_q->cscn)) {
> retry_count++;
> /* Retry for some time before giving up */
> - if (retry_count > CONG_RETRY_COUNT)
> + if (retry_count > CONG_RETRY_COUNT) {
> + if (dpaa2_q->tm_sw_td)
> + goto sw_td;
> goto skip_tx;
> + }
> }
>
> frames_to_send = (nb_pkts > dpaa2_eqcr_size) ?
> @@ -1961,6 +1964,25 @@ dpaa2_dev_tx_ordered(void *queue, struct rte_mbuf
> **bufs, uint16_t nb_pkts)
> rte_pktmbuf_free_seg(buf_to_free[loop].seg);
> }
>
> + return num_tx;
> +sw_td:
> + loop = 0;
> + while (loop < num_tx) {
> + if (unlikely(RTE_MBUF_HAS_EXTBUF(*bufs)))
> + rte_pktmbuf_free(*bufs);
> + bufs++;
> + loop++;
> + }
This looks like a possible bug.
Is there a double free here if there are external buffers.
> +
> + /* free the pending buffers */
> + while (nb_pkts) {
> + rte_pktmbuf_free(*bufs);
> + bufs++;
> + nb_pkts--;
> + num_tx++;
> + }
Why not use rte_pktmbuf_free_bulk here?
> + dpaa2_q->tx_pkts += num_tx;
> +
> return num_tx;
> }
>
> diff --git a/drivers/net/dpaa2/dpaa2_tm.c b/drivers/net/dpaa2/dpaa2_tm.c
> index dbf66c756e..36e815c356 100644
> --- a/drivers/net/dpaa2/dpaa2_tm.c
> +++ b/drivers/net/dpaa2/dpaa2_tm.c
> @@ -611,41 +611,39 @@ dpaa2_tm_configure_queue(struct rte_eth_dev *dev,
> struct dpaa2_tm_node *node)
> }
> dpaa2_q->fqid = qid.fqid;
>
> - /* setting congestion notification */
> - if (!(priv->flags & DPAA2_TX_CGR_OFF)) {
> - struct dpni_congestion_notification_cfg cong_notif_cfg = {0};
> -
> - cong_notif_cfg.units = DPNI_CONGESTION_UNIT_FRAMES;
> - cong_notif_cfg.threshold_entry = dpaa2_q->nb_desc;
> - /* Notify that the queue is not congested when the data in
> - * the queue is below this thershold.(90% of value)
> - */
> - cong_notif_cfg.threshold_exit = (dpaa2_q->nb_desc * 9) / 10;
> - cong_notif_cfg.message_ctx = 0;
> - iova = DPAA2_VADDR_TO_IOVA_AND_CHECK(dpaa2_q->cscn,
> - sizeof(struct qbman_result));
> - if (iova == RTE_BAD_IOVA) {
> - DPAA2_PMD_ERR("No IOMMU map for cscn(%p)",
> dpaa2_q->cscn);
> - return -ENOBUFS;
> - }
> - cong_notif_cfg.message_iova = iova;
> - cong_notif_cfg.dest_cfg.dest_type = DPNI_DEST_NONE;
> - cong_notif_cfg.notification_mode =
> + /* setting taildrop through congestion notification */
> + struct dpni_congestion_notification_cfg cong_notif_cfg = {0};
> +
> + cong_notif_cfg.units = DPNI_CONGESTION_UNIT_FRAMES;
> + cong_notif_cfg.threshold_entry = dpaa2_q->nb_desc;
> + /* Notify that the queue is not congested when the data in
> + * the queue is below this thershold.(90% of value)
> + */
> + cong_notif_cfg.threshold_exit = (dpaa2_q->nb_desc * 9) / 10;
> + cong_notif_cfg.message_ctx = 0;
> +
> + iova = DPAA2_VADDR_TO_IOVA_AND_CHECK(dpaa2_q->cscn,
> + sizeof(struct qbman_result));
> + if (iova == RTE_BAD_IOVA) {
> + DPAA2_PMD_ERR("No IOMMU map for cscn(%p)", dpaa2_q->cscn);
> + return -ENOBUFS;
> + }
> + cong_notif_cfg.message_iova = iova;
> + cong_notif_cfg.dest_cfg.dest_type = DPNI_DEST_NONE;
> + cong_notif_cfg.notification_mode =
> DPNI_CONG_OPT_WRITE_MEM_ON_ENTER |
> DPNI_CONG_OPT_WRITE_MEM_ON_EXIT |
> DPNI_CONG_OPT_COHERENT_WRITE;
> - cong_notif_cfg.cg_point = DPNI_CP_QUEUE;
> + cong_notif_cfg.cg_point = DPNI_CP_QUEUE;
>
> - ret = dpni_set_congestion_notification(dpni, CMD_PRI_LOW,
> - priv->token,
> - DPNI_QUEUE_TX,
> - ((node->parent->channel_id << 8) |
> tc_id),
> - &cong_notif_cfg);
> - if (ret) {
> - DPAA2_PMD_ERR("Error in setting tx congestion
> notification: "
> - "err=%d", ret);
> - return -ret;
> - }
> + ret = dpni_set_congestion_notification(dpni, CMD_PRI_LOW,
> + priv->token, DPNI_QUEUE_TX,
> + ((node->parent->channel_id << 8) | tc_id),
> + &cong_notif_cfg);
> + if (ret) {
> + DPAA2_PMD_ERR("Error in setting tx congestion notification: "
> + "err=%d", ret);
> + return -ret;
> }
> dpaa2_q->tm_sw_td = true;
>
