> -----Original Message-----
> From: Julien Meunier <julien.meun...@nokia.com>
> Sent: Tuesday, September 28, 2021 01:18
> To: dev@dpdk.org
> Cc: sta...@dpdk.org; Richardson, Bruce <bruce.richard...@intel.com>; Wang,
> Haiyue
> <haiyue.w...@intel.com>
> Subject: [PATCH] net/ixgbe: fix RxQ/TxQ release
>
> On the vector implementation, during the tear-down, the mbufs not
> drained in the RxQ and TxQ are freed based on an algorithm which
> supposed that the number of descriptors is a power of 2 (max_desc).
> Based on this hypothesis, this algorithm uses a bitmask in order to
> detect an index overflow during the iteration, and to restart the loop
> from 0.
>
> However, there is no such power of 2 requirement in the ixgbe for the
> number of descriptors in the RxQ / TxQ. The only requirement is to have
> a number correctly aligned.
>
> If a user requested to configure a number of descriptors which is not a
> power of 2, as a consequence, during the tear-down, it was possible to
> be in an infinite loop, and to never reach the exit loop condition.
>
Are you able to setup not a power of 2 successfully ?
int
rte_eth_tx_queue_setup(uint16_t port_id, uint16_t tx_queue_id,
uint16_t nb_tx_desc, unsigned int socket_id,
const struct rte_eth_txconf *tx_conf)
{
...
if (nb_tx_desc > dev_info.tx_desc_lim.nb_max ||
nb_tx_desc < dev_info.tx_desc_lim.nb_min ||
nb_tx_desc % dev_info.tx_desc_lim.nb_align != 0) {
RTE_ETHDEV_LOG(ERR,
"Invalid value for nb_tx_desc(=%hu), should be: <= %hu,
>= %hu, and a product of %hu\n",
nb_tx_desc, dev_info.tx_desc_lim.nb_max,
dev_info.tx_desc_lim.nb_min,
dev_info.tx_desc_lim.nb_align);
return -EINVAL;
}
...
}
> By removing the bitmask and changing the loop method, we can avoid this
> issue, and allow the user to configure a RxQ / TxQ which is not a power
> of 2.
>
> Fixes: c95584dc2b18 ("ixgbe: new vectorized functions for Rx/Tx")
> Cc: bruce.richard...@intel.com
> Cc: sta...@dpdk.org
>
> Signed-off-by: Julien Meunier <julien.meun...@nokia.com>
> ---
> drivers/net/ixgbe/ixgbe_rxtx_vec_common.h | 20 +++++++++++++-------
> 1 file changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/ixgbe/ixgbe_rxtx_vec_common.h
> b/drivers/net/ixgbe/ixgbe_rxtx_vec_common.h
> index adba855ca3..8912558918 100644
> --- a/drivers/net/ixgbe/ixgbe_rxtx_vec_common.h
> +++ b/drivers/net/ixgbe/ixgbe_rxtx_vec_common.h
> @@ -150,11 +150,14 @@ _ixgbe_tx_queue_release_mbufs_vec(struct ixgbe_tx_queue
> *txq)
> return;
>
> /* release the used mbufs in sw_ring */
> - for (i = txq->tx_next_dd - (txq->tx_rs_thresh - 1);
> - i != txq->tx_tail;
> - i = (i + 1) & max_desc) {
> + i = txq->tx_next_dd - (txq->tx_rs_thresh - 1);
> + while (i != txq->tx_tail) {
> txe = &txq->sw_ring_v[i];
> rte_pktmbuf_free_seg(txe->mbuf);
> +
> + i = i + 1;
> + if (i > max_desc)
> + i = 0;
> }
> txq->nb_tx_free = max_desc;
>
> @@ -168,7 +171,7 @@ _ixgbe_tx_queue_release_mbufs_vec(struct ixgbe_tx_queue
> *txq)
> static inline void
> _ixgbe_rx_queue_release_mbufs_vec(struct ixgbe_rx_queue *rxq)
> {
> - const unsigned int mask = rxq->nb_rx_desc - 1;
> + const unsigned int max_desc = rxq->nb_rx_desc - 1;
> unsigned int i;
>
> if (rxq->sw_ring == NULL || rxq->rxrearm_nb >= rxq->nb_rx_desc)
> @@ -181,11 +184,14 @@ _ixgbe_rx_queue_release_mbufs_vec(struct ixgbe_rx_queue
> *rxq)
> rte_pktmbuf_free_seg(rxq->sw_ring[i].mbuf);
> }
> } else {
> - for (i = rxq->rx_tail;
> - i != rxq->rxrearm_start;
> - i = (i + 1) & mask) {
> + i = rxq->rx_tail;
> + while (i != rxq->rxrearm_start) {
> if (rxq->sw_ring[i].mbuf != NULL)
> rte_pktmbuf_free_seg(rxq->sw_ring[i].mbuf);
> +
> + i = i + 1;
> + if (i > max_desc)
> + i = 0;
> }
> }
>
> --
> 2.17.1
