From 8a90f3d8d09b5fa2e7a6a7b83b8e4868acebbe01 Mon Sep 17 00:00:00 2001 From: Igor Chauskin Date: Tue, 26 Jan 2021 19:32:25 +0100 Subject: [PATCH] net/ena: fix Tx SQ free space assessment Before starting transmission of Tx burst, the driver checked the available space in the sq and limited the number of packets for transmission accordingly. The calculation was incorrect for fragmented packets and potentially had significantly limited the length of Tx bursts. This patch removes the assessment and pushes packets to the sq as long as the burst is not exhausted and space is available in the sq. Correct evaluation of the required space isn't possible before the burst because it depends on the number of segments of each packet. This patch adds per-packet space evaluation for each packet before attempting to process it. In case there is not enough queue space, the burst will just stop without error. Fixes: 2061fe41f212 ("net/ena: linearize Tx mbuf") Cc: stable@dpdk.org Signed-off-by: Igor Chauskin Reviewed-by: Michal Krawczyk --- drivers/net/ena/ena_ethdev.c | 35 ++++++++++++++++++++++++++--------- 1 file changed, 26 insertions(+), 9 deletions(-) diff --git a/drivers/net/ena/ena_ethdev.c b/drivers/net/ena/ena_ethdev.c index 1728ceb9a8..8a937d7f27 100644 --- a/drivers/net/ena/ena_ethdev.c +++ b/drivers/net/ena/ena_ethdev.c @@ -2359,8 +2359,8 @@ static void ena_update_hints(struct ena_adapter *adapter, } } -static int ena_check_and_linearize_mbuf(struct ena_ring *tx_ring, - struct rte_mbuf *mbuf) +static int ena_check_space_and_linearize_mbuf(struct ena_ring *tx_ring, + struct rte_mbuf *mbuf) { struct ena_com_dev *ena_dev; int num_segments, header_len, rc; @@ -2370,13 +2370,21 @@ static int ena_check_and_linearize_mbuf(struct ena_ring *tx_ring, header_len = mbuf->data_len; if (likely(num_segments < tx_ring->sgl_size)) - return 0; + goto checkspace; if (ena_dev->tx_mem_queue_type == ENA_ADMIN_PLACEMENT_POLICY_DEV && (num_segments == tx_ring->sgl_size) && (header_len < tx_ring->tx_max_header_size)) - return 0; + goto checkspace; + /* Checking for space for 2 additional metadata descriptors due to + * possible header split and metadata descriptor. Linearization will + * be needed so we reduce the segments number from num_segments to 1 + */ + if (!ena_com_sq_have_enough_space(tx_ring->ena_com_io_sq, 3)) { + PMD_DRV_LOG(DEBUG, "Not enough space in the tx queue\n"); + return ENA_COM_NO_MEM; + } ++tx_ring->tx_stats.linearize; rc = rte_pktmbuf_linearize(mbuf); if (unlikely(rc)) { @@ -2386,7 +2394,19 @@ static int ena_check_and_linearize_mbuf(struct ena_ring *tx_ring, return rc; } - return rc; + return 0; + +checkspace: + /* Checking for space for 2 additional metadata descriptors due to + * possible header split and metadata descriptor + */ + if (!ena_com_sq_have_enough_space(tx_ring->ena_com_io_sq, + num_segments + 2)) { + PMD_DRV_LOG(DEBUG, "Not enough space in the tx queue\n"); + return ENA_COM_NO_MEM; + } + + return 0; } static void ena_tx_map_mbuf(struct ena_ring *tx_ring, @@ -2473,7 +2493,7 @@ static int ena_xmit_mbuf(struct ena_ring *tx_ring, struct rte_mbuf *mbuf) int nb_hw_desc; int rc; - rc = ena_check_and_linearize_mbuf(tx_ring, mbuf); + rc = ena_check_space_and_linearize_mbuf(tx_ring, mbuf); if (unlikely(rc)) return rc; @@ -2580,9 +2600,6 @@ static uint16_t eth_ena_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, return 0; } - nb_pkts = RTE_MIN(ena_com_free_q_entries(tx_ring->ena_com_io_sq), - nb_pkts); - for (sent_idx = 0; sent_idx < nb_pkts; sent_idx++) { if (ena_xmit_mbuf(tx_ring, tx_pkts[sent_idx])) break; -- 2.20.1