From de3d6fa81e684af5817dc379ffc394235a9666cc Mon Sep 17 00:00:00 2001 From: Tariq Toukan Date: Tue, 20 Sep 2016 14:39:39 +0300 Subject: [PATCH] net/mlx4_en: Add branch prediction hints in RX data-path Add likely/unlikely hints to improve branch predictions in the RX data-path. Signed-off-by: Tariq Toukan Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_rx.c | 26 ++++++++++++---------- 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c index c46355bce613..6e474af3fb1f 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c @@ -72,7 +72,7 @@ static int mlx4_alloc_pages(struct mlx4_en_priv *priv, } dma = dma_map_page(priv->ddev, page, 0, PAGE_SIZE << order, frag_info->dma_dir); - if (dma_mapping_error(priv->ddev, dma)) { + if (unlikely(dma_mapping_error(priv->ddev, dma))) { put_page(page); return -ENOMEM; } @@ -108,7 +108,8 @@ static int mlx4_en_alloc_frags(struct mlx4_en_priv *priv, ring_alloc[i].page_size) continue; - if (mlx4_alloc_pages(priv, &page_alloc[i], frag_info, gfp)) + if (unlikely(mlx4_alloc_pages(priv, &page_alloc[i], + frag_info, gfp))) goto out; } @@ -585,7 +586,7 @@ static int mlx4_en_complete_rx_desc(struct mlx4_en_priv *priv, frag_info = &priv->frag_info[nr]; if (length <= frag_info->frag_prefix_size) break; - if (!frags[nr].page) + if (unlikely(!frags[nr].page)) goto fail; dma = be64_to_cpu(rx_desc->data[nr].addr); @@ -625,7 +626,7 @@ static struct sk_buff *mlx4_en_rx_skb(struct mlx4_en_priv *priv, dma_addr_t dma; skb = netdev_alloc_skb(priv->dev, SMALL_PACKET_SIZE + NET_IP_ALIGN); - if (!skb) { + if (unlikely(!skb)) { en_dbg(RX_ERR, priv, "Failed allocating skb\n"); return NULL; } @@ -736,7 +737,8 @@ static int get_fixed_ipv6_csum(__wsum hw_checksum, struct sk_buff *skb, { __wsum csum_pseudo_hdr = 0; - if (ipv6h->nexthdr == IPPROTO_FRAGMENT || ipv6h->nexthdr == IPPROTO_HOPOPTS) + if (unlikely(ipv6h->nexthdr == IPPROTO_FRAGMENT || + ipv6h->nexthdr == IPPROTO_HOPOPTS)) return -1; hw_checksum = csum_add(hw_checksum, (__force __wsum)htons(ipv6h->nexthdr)); @@ -769,7 +771,7 @@ static int check_csum(struct mlx4_cqe *cqe, struct sk_buff *skb, void *va, get_fixed_ipv4_csum(hw_checksum, skb, hdr); #if IS_ENABLED(CONFIG_IPV6) else if (cqe->status & cpu_to_be16(MLX4_CQE_STATUS_IPV6)) - if (get_fixed_ipv6_csum(hw_checksum, skb, hdr)) + if (unlikely(get_fixed_ipv6_csum(hw_checksum, skb, hdr))) return -1; #endif return 0; @@ -796,10 +798,10 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud u64 timestamp; bool l2_tunnel; - if (!priv->port_up) + if (unlikely(!priv->port_up)) return 0; - if (budget <= 0) + if (unlikely(budget <= 0)) return polled; /* Protect accesses to: ring->xdp_prog, priv->mac_hash list */ @@ -902,9 +904,9 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud case XDP_PASS: break; case XDP_TX: - if (!mlx4_en_xmit_frame(frags, dev, + if (likely(!mlx4_en_xmit_frame(frags, dev, length, tx_index, - &doorbell_pending)) + &doorbell_pending))) goto consumed; goto xdp_drop; /* Drop on xmit failure */ default: @@ -912,7 +914,7 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud case XDP_ABORTED: case XDP_DROP: xdp_drop: - if (mlx4_en_rx_recycle(ring, frags)) + if (likely(mlx4_en_rx_recycle(ring, frags))) goto consumed; goto next; } @@ -1016,7 +1018,7 @@ xdp_drop: /* GRO not possible, complete processing here */ skb = mlx4_en_rx_skb(priv, rx_desc, frags, length); - if (!skb) { + if (unlikely(!skb)) { ring->dropped++; goto next; } -- 2.20.1