Add likely/unlikely hints to improve branch predictions
in the RX data-path.
Signed-off-by: Tariq Toukan <tar...@mellanox.com>
---
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 6758292311f4..bb7ccb109aa4 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 */
@@ -902,16 +904,16 @@ 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;
break;
default:
bpf_warn_invalid_xdp_action(act);
case XDP_ABORTED:
case XDP_DROP:
- if (mlx4_en_rx_recycle(ring, frags))
+ if (likely(mlx4_en_rx_recycle(ring, frags)))
goto consumed;
goto next;
}
@@ -1015,7 +1017,7 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct
mlx4_en_cq *cq, int bud
/* 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;
}
--
1.8.3.1
