[dpdk-dev] [PATCH v2 4/8] drivers/net: don't touch mbuf next or nb segs on Rx

Olivier Matz olivier.matz at 6wind.com
Tue Apr 4 18:28:03 CEST 2017


Now that the m->next pointer and m->nb_segs is expected to be set (to
NULL and 1 respectively) after a mempool_get(), we can avoid to write them
in the Rx functions of drivers.

Only some drivers are patched, it's not an exhaustive patch. It gives
the idea to do the same in other drivers.

Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
---
 drivers/net/i40e/i40e_rxtx_vec_sse.c    | 6 ------
 drivers/net/ixgbe/ixgbe_rxtx.c          | 8 --------
 drivers/net/ixgbe/ixgbe_rxtx_vec_neon.c | 6 ------
 drivers/net/ixgbe/ixgbe_rxtx_vec_sse.c  | 6 ------
 drivers/net/null/rte_eth_null.c         | 2 --
 drivers/net/virtio/virtio_rxtx.c        | 4 ----
 6 files changed, 32 deletions(-)

diff --git a/drivers/net/i40e/i40e_rxtx_vec_sse.c b/drivers/net/i40e/i40e_rxtx_vec_sse.c
index b95cc8e19..2f861fde8 100644
--- a/drivers/net/i40e/i40e_rxtx_vec_sse.c
+++ b/drivers/net/i40e/i40e_rxtx_vec_sse.c
@@ -424,12 +424,6 @@ _recv_raw_pkts_vec(struct i40e_rx_queue *rxq, struct rte_mbuf **rx_pkts,
 			/* store the resulting 32-bit value */
 			*(int *)split_packet = _mm_cvtsi128_si32(eop_bits);
 			split_packet += RTE_I40E_DESCS_PER_LOOP;
-
-			/* zero-out next pointers */
-			rx_pkts[pos]->next = NULL;
-			rx_pkts[pos + 1]->next = NULL;
-			rx_pkts[pos + 2]->next = NULL;
-			rx_pkts[pos + 3]->next = NULL;
 		}
 
 		/* C.3 calc available number of desc */
diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
index 879e215f6..5023617a2 100644
--- a/drivers/net/ixgbe/ixgbe_rxtx.c
+++ b/drivers/net/ixgbe/ixgbe_rxtx.c
@@ -1556,8 +1556,6 @@ ixgbe_rx_alloc_bufs(struct ixgbe_rx_queue *rxq, bool reset_mbuf)
 		/* populate the static rte mbuf fields */
 		mb = rxep[i].mbuf;
 		if (reset_mbuf) {
-			mb->next = NULL;
-			mb->nb_segs = 1;
 			mb->port = rxq->port_id;
 		}
 
@@ -2165,12 +2163,6 @@ ixgbe_recv_pkts_lro(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts,
 			goto next_desc;
 		}
 
-		/*
-		 * This is the last buffer of the received packet - return
-		 * the current cluster to the user.
-		 */
-		rxm->next = NULL;
-
 		/* Initialize the first mbuf of the returned packet */
 		ixgbe_fill_cluster_head_buf(first_seg, &rxd, rxq, staterr);
 
diff --git a/drivers/net/ixgbe/ixgbe_rxtx_vec_neon.c b/drivers/net/ixgbe/ixgbe_rxtx_vec_neon.c
index e2715cb96..2c0416179 100644
--- a/drivers/net/ixgbe/ixgbe_rxtx_vec_neon.c
+++ b/drivers/net/ixgbe/ixgbe_rxtx_vec_neon.c
@@ -330,12 +330,6 @@ _recv_raw_pkts_vec(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_pkts,
 			*(int *)split_packet = ~stat & IXGBE_VPMD_DESC_EOP_MASK;
 
 			split_packet += RTE_IXGBE_DESCS_PER_LOOP;
-
-			/* zero-out next pointers */
-			rx_pkts[pos]->next = NULL;
-			rx_pkts[pos + 1]->next = NULL;
-			rx_pkts[pos + 2]->next = NULL;
-			rx_pkts[pos + 3]->next = NULL;
 		}
 
 		rte_prefetch_non_temporal(rxdp + RTE_IXGBE_DESCS_PER_LOOP);
diff --git a/drivers/net/ixgbe/ixgbe_rxtx_vec_sse.c b/drivers/net/ixgbe/ixgbe_rxtx_vec_sse.c
index abbf2841f..65c5da3c7 100644
--- a/drivers/net/ixgbe/ixgbe_rxtx_vec_sse.c
+++ b/drivers/net/ixgbe/ixgbe_rxtx_vec_sse.c
@@ -425,12 +425,6 @@ _recv_raw_pkts_vec(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_pkts,
 			/* store the resulting 32-bit value */
 			*(int *)split_packet = _mm_cvtsi128_si32(eop_bits);
 			split_packet += RTE_IXGBE_DESCS_PER_LOOP;
-
-			/* zero-out next pointers */
-			rx_pkts[pos]->next = NULL;
-			rx_pkts[pos + 1]->next = NULL;
-			rx_pkts[pos + 2]->next = NULL;
-			rx_pkts[pos + 3]->next = NULL;
 		}
 
 		/* C.3 calc available number of desc */
diff --git a/drivers/net/null/rte_eth_null.c b/drivers/net/null/rte_eth_null.c
index 57203e2ed..7e14da0e0 100644
--- a/drivers/net/null/rte_eth_null.c
+++ b/drivers/net/null/rte_eth_null.c
@@ -112,8 +112,6 @@ eth_null_rx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
 			break;
 		bufs[i]->data_len = (uint16_t)packet_size;
 		bufs[i]->pkt_len = packet_size;
-		bufs[i]->nb_segs = 1;
-		bufs[i]->next = NULL;
 		bufs[i]->port = h->internals->port_id;
 	}
 
diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index cab6e8fc0..b3e6d8027 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -772,8 +772,6 @@ virtio_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
 		rxm->ol_flags = 0;
 		rxm->vlan_tci = 0;
 
-		rxm->nb_segs = 1;
-		rxm->next = NULL;
 		rxm->pkt_len = (uint32_t)(len[i] - hdr_size);
 		rxm->data_len = (uint16_t)(len[i] - hdr_size);
 
@@ -900,7 +898,6 @@ virtio_recv_mergeable_pkts(void *rx_queue,
 
 		rxm->data_off = RTE_PKTMBUF_HEADROOM;
 		rxm->nb_segs = seg_num;
-		rxm->next = NULL;
 		rxm->ol_flags = 0;
 		rxm->vlan_tci = 0;
 		rxm->pkt_len = (uint32_t)(len[0] - hdr_size);
@@ -945,7 +942,6 @@ virtio_recv_mergeable_pkts(void *rx_queue,
 				rxm = rcv_pkts[extra_idx];
 
 				rxm->data_off = RTE_PKTMBUF_HEADROOM - hdr_size;
-				rxm->next = NULL;
 				rxm->pkt_len = (uint32_t)(len[extra_idx]);
 				rxm->data_len = (uint16_t)(len[extra_idx]);
 
-- 
2.11.0



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