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net/mlx5e: RX, Add a prefetch command for small L1_CACHE_BYTES
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A single cacheline might not contain the packet header for
small L1_CACHE_BYTES values.
Use net_prefetch() as it issues an additional prefetch
in this case.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Tariq Toukan authored and davem330 committed Aug 26, 2020
1 parent f468f21 commit e20f0db
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Showing 4 changed files with 11 additions and 13 deletions.
4 changes: 2 additions & 2 deletions drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
Original file line number Diff line number Diff line change
Expand Up @@ -201,7 +201,7 @@ static void mlx5e_xdp_mpwqe_session_start(struct mlx5e_xdpsq *sq)
pi = mlx5e_xdpsq_get_next_pi(sq, MLX5_SEND_WQE_MAX_WQEBBS);
session->wqe = MLX5E_TX_FETCH_WQE(sq, pi);

prefetchw(session->wqe->data);
net_prefetchw(session->wqe->data);
session->ds_count = MLX5E_XDP_TX_EMPTY_DS_COUNT;
session->pkt_count = 0;

Expand Down Expand Up @@ -322,7 +322,7 @@ mlx5e_xmit_xdp_frame(struct mlx5e_xdpsq *sq, struct mlx5e_xdp_xmit_data *xdptxd,

struct mlx5e_xdpsq_stats *stats = sq->stats;

prefetchw(wqe);
net_prefetchw(wqe);

if (unlikely(dma_len < MLX5E_XDP_MIN_INLINE || sq->hw_mtu < dma_len)) {
stats->err++;
Expand Down
4 changes: 2 additions & 2 deletions drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
Original file line number Diff line number Diff line change
Expand Up @@ -49,7 +49,7 @@ struct sk_buff *mlx5e_xsk_skb_from_cqe_mpwrq_linear(struct mlx5e_rq *rq,
xdp->data_end = xdp->data + cqe_bcnt32;
xdp_set_data_meta_invalid(xdp);
xsk_buff_dma_sync_for_cpu(xdp);
prefetch(xdp->data);
net_prefetch(xdp->data);

rcu_read_lock();
consumed = mlx5e_xdp_handle(rq, NULL, &cqe_bcnt32, xdp);
Expand Down Expand Up @@ -100,7 +100,7 @@ struct sk_buff *mlx5e_xsk_skb_from_cqe_linear(struct mlx5e_rq *rq,
xdp->data_end = xdp->data + cqe_bcnt;
xdp_set_data_meta_invalid(xdp);
xsk_buff_dma_sync_for_cpu(xdp);
prefetch(xdp->data);
net_prefetch(xdp->data);

if (unlikely(get_cqe_opcode(cqe) != MLX5_CQE_RESP_SEND)) {
rq->stats->wqe_err++;
Expand Down
13 changes: 6 additions & 7 deletions drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,6 @@
* SOFTWARE.
*/

#include <linux/prefetch.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/tcp.h>
Expand Down Expand Up @@ -1141,8 +1140,8 @@ mlx5e_skb_from_cqe_linear(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe,

dma_sync_single_range_for_cpu(rq->pdev, di->addr, wi->offset,
frag_size, DMA_FROM_DEVICE);
prefetchw(va); /* xdp_frame data area */
prefetch(data);
net_prefetchw(va); /* xdp_frame data area */
net_prefetch(data);

rcu_read_lock();
mlx5e_fill_xdp_buff(rq, va, rx_headroom, cqe_bcnt, &xdp);
Expand Down Expand Up @@ -1184,7 +1183,7 @@ mlx5e_skb_from_cqe_nonlinear(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe,
return NULL;
}

prefetchw(skb->data);
net_prefetchw(skb->data);

while (byte_cnt) {
u16 frag_consumed_bytes =
Expand Down Expand Up @@ -1399,7 +1398,7 @@ mlx5e_skb_from_cqe_mpwrq_nonlinear(struct mlx5e_rq *rq, struct mlx5e_mpw_info *w
return NULL;
}

prefetchw(skb->data);
net_prefetchw(skb->data);

if (unlikely(frag_offset >= PAGE_SIZE)) {
di++;
Expand Down Expand Up @@ -1452,8 +1451,8 @@ mlx5e_skb_from_cqe_mpwrq_linear(struct mlx5e_rq *rq, struct mlx5e_mpw_info *wi,

dma_sync_single_range_for_cpu(rq->pdev, di->addr, head_offset,
frag_size, DMA_FROM_DEVICE);
prefetchw(va); /* xdp_frame data area */
prefetch(data);
net_prefetchw(va); /* xdp_frame data area */
net_prefetch(data);

rcu_read_lock();
mlx5e_fill_xdp_buff(rq, va, rx_headroom, cqe_bcnt32, &xdp);
Expand Down
3 changes: 1 addition & 2 deletions drivers/net/ethernet/mellanox/mlx5/core/en_selftest.c
Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,6 @@
* SOFTWARE.
*/

#include <linux/prefetch.h>
#include <linux/ip.h>
#include <linux/udp.h>
#include <net/udp.h>
Expand Down Expand Up @@ -115,7 +114,7 @@ static struct sk_buff *mlx5e_test_get_udp_skb(struct mlx5e_priv *priv)
return NULL;
}

prefetchw(skb->data);
net_prefetchw(skb->data);
skb_reserve(skb, NET_IP_ALIGN);

/* Reserve for ethernet and IP header */
Expand Down

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