[PATCH net-next 0/3] net_prefetch API

[PATCH net-next 0/3] net_prefetch API

[Tariq Toukan]

Hi,

This patchset adds a common net API for L1 cacheline size-aware prefetch.

Patch 1 introduces the common API in net and aligns the drivers to use it.
Patches 2 and 3 add usage in mlx4 and mlx5 Eth drivers.

Series generated against net-next commit:
079f921e9f4d Merge tag 'batadv-next-for-davem-20200824' of git://git.open-mesh.org/linux-merge

Thanks,
Tariq.


Tariq Toukan (3):
  net: Take common prefetch code structure into a function
  net/mlx5e: RX, Add a prefetch command for small L1_CACHE_BYTES
  net/mlx4_en: RX, Add a prefetch command for small L1_CACHE_BYTES

 drivers/net/ethernet/chelsio/cxgb3/sge.c         |  5 +----
 drivers/net/ethernet/hisilicon/hns/hns_enet.c    |  5 +----
 drivers/net/ethernet/hisilicon/hns3/hns3_enet.c  |  5 +----
 drivers/net/ethernet/intel/fm10k/fm10k_main.c    |  5 +----
 drivers/net/ethernet/intel/i40e/i40e_txrx.c      | 12 ++++--------
 drivers/net/ethernet/intel/iavf/iavf_txrx.c      | 11 +++--------
 drivers/net/ethernet/intel/ice/ice_txrx.c        | 10 ++--------
 drivers/net/ethernet/intel/igb/igb_main.c        | 10 ++--------
 drivers/net/ethernet/intel/igc/igc_main.c        | 10 ++--------
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c    | 11 +++--------
 .../net/ethernet/intel/ixgbevf/ixgbevf_main.c    | 11 +++--------
 drivers/net/ethernet/mellanox/mlx4/en_rx.c       |  2 +-
 drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c |  4 ++--
 .../net/ethernet/mellanox/mlx5/core/en/xsk/rx.c  |  4 ++--
 drivers/net/ethernet/mellanox/mlx5/core/en_rx.c  | 13 ++++++-------
 .../ethernet/mellanox/mlx5/core/en_selftest.c    |  3 +--
 include/linux/netdevice.h                        | 16 ++++++++++++++++
 17 files changed, 51 insertions(+), 86 deletions(-)

-- 
2.21.0

[PATCH net-next 1/3] net: Take common prefetch code structure into a function

[Tariq Toukan]

Many device drivers use the same prefetch code structure to
deal with small L1 cacheline size.
Take this code into a function and call it from the drivers.

Suggested-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
---
 drivers/net/ethernet/chelsio/cxgb3/sge.c         |  5 +----
 drivers/net/ethernet/hisilicon/hns/hns_enet.c    |  5 +----
 drivers/net/ethernet/hisilicon/hns3/hns3_enet.c  |  5 +----
 drivers/net/ethernet/intel/fm10k/fm10k_main.c    |  5 +----
 drivers/net/ethernet/intel/i40e/i40e_txrx.c      | 12 ++++--------
 drivers/net/ethernet/intel/iavf/iavf_txrx.c      | 11 +++--------
 drivers/net/ethernet/intel/ice/ice_txrx.c        | 10 ++--------
 drivers/net/ethernet/intel/igb/igb_main.c        | 10 ++--------
 drivers/net/ethernet/intel/igc/igc_main.c        | 10 ++--------
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c    | 11 +++--------
 .../net/ethernet/intel/ixgbevf/ixgbevf_main.c    | 11 +++--------
 include/linux/netdevice.h                        | 16 ++++++++++++++++
 12 files changed, 39 insertions(+), 72 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb3/sge.c b/drivers/net/ethernet/chelsio/cxgb3/sge.c
index 6dabbf1502c7..ee6188dea705 100644
--- a/drivers/net/ethernet/chelsio/cxgb3/sge.c
+++ b/drivers/net/ethernet/chelsio/cxgb3/sge.c
@@ -2372,10 +2372,7 @@ static int process_responses(struct adapter *adap, struct sge_qset *qs,
 			if (fl->use_pages) {
 				void *addr = fl->sdesc[fl->cidx].pg_chunk.va;
 
-				prefetch(addr);
-#if L1_CACHE_BYTES < 128
-				prefetch(addr + L1_CACHE_BYTES);
-#endif
+				net_prefetch(addr);
 				__refill_fl(adap, fl);
 				if (lro > 0) {
 					lro_add_page(adap, qs, fl,
diff --git a/drivers/net/ethernet/hisilicon/hns/hns_enet.c b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
index 23f278e46975..3af33ade7b60 100644
--- a/drivers/net/ethernet/hisilicon/hns/hns_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
@@ -557,10 +557,7 @@ static int hns_nic_poll_rx_skb(struct hns_nic_ring_data *ring_data,
 	va = (unsigned char *)desc_cb->buf + desc_cb->page_offset;
 
 	/* prefetch first cache line of first page */
-	prefetch(va);
-#if L1_CACHE_BYTES < 128
-	prefetch(va + L1_CACHE_BYTES);
-#endif
+	net_prefetch(va);
 
 	skb = *out_skb = napi_alloc_skb(&ring_data->napi,
 					HNS_RX_HEAD_SIZE);
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 87776ce3539b..1a1ba6a41bfe 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -3091,10 +3091,7 @@ static int hns3_handle_rx_bd(struct hns3_enet_ring *ring)
 	 * lines. In such a case, single fetch would suffice to cache in the
 	 * relevant part of the header.
 	 */
-	prefetch(ring->va);
-#if L1_CACHE_BYTES < 128
-	prefetch(ring->va + L1_CACHE_BYTES);
-#endif
+	net_prefetch(ring->va);
 
 	if (!skb) {
 		ret = hns3_alloc_skb(ring, length, ring->va);
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_main.c b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
index d88dd41a9442..99b8252eb969 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_main.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
@@ -310,10 +310,7 @@ static struct sk_buff *fm10k_fetch_rx_buffer(struct fm10k_ring *rx_ring,
 				  rx_buffer->page_offset;
 
 		/* prefetch first cache line of first page */
-		prefetch(page_addr);
-#if L1_CACHE_BYTES < 128
-		prefetch((void *)((u8 *)page_addr + L1_CACHE_BYTES));
-#endif
+		net_prefetch(page_addr);
 
 		/* allocate a skb to store the frags */
 		skb = napi_alloc_skb(&rx_ring->q_vector->napi,
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 3e5c566ceb01..432a984ac335 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -1992,10 +1992,8 @@ static struct sk_buff *i40e_construct_skb(struct i40e_ring *rx_ring,
 	struct sk_buff *skb;
 
 	/* prefetch first cache line of first page */
-	prefetch(xdp->data);
-#if L1_CACHE_BYTES < 128
-	prefetch(xdp->data + L1_CACHE_BYTES);
-#endif
+	net_prefetch(xdp->data);
+
 	/* Note, we get here by enabling legacy-rx via:
 	 *
 	 *    ethtool --set-priv-flags <dev> legacy-rx on
@@ -2078,10 +2076,8 @@ static struct sk_buff *i40e_build_skb(struct i40e_ring *rx_ring,
 	 * likely have a consumer accessing first few bytes of meta
 	 * data, and then actual data.
 	 */
-	prefetch(xdp->data_meta);
-#if L1_CACHE_BYTES < 128
-	prefetch(xdp->data_meta + L1_CACHE_BYTES);
-#endif
+	net_prefetch(xdp->data_meta);
+
 	/* build an skb around the page buffer */
 	skb = build_skb(xdp->data_hard_start, truesize);
 	if (unlikely(!skb))
diff --git a/drivers/net/ethernet/intel/iavf/iavf_txrx.c b/drivers/net/ethernet/intel/iavf/iavf_txrx.c
index ca041b39ffda..256fa07d54d5 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_txrx.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_txrx.c
@@ -1309,10 +1309,7 @@ static struct sk_buff *iavf_construct_skb(struct iavf_ring *rx_ring,
 		return NULL;
 	/* prefetch first cache line of first page */
 	va = page_address(rx_buffer->page) + rx_buffer->page_offset;
-	prefetch(va);
-#if L1_CACHE_BYTES < 128
-	prefetch(va + L1_CACHE_BYTES);
-#endif
+	net_prefetch(va);
 
 	/* allocate a skb to store the frags */
 	skb = __napi_alloc_skb(&rx_ring->q_vector->napi,
@@ -1376,10 +1373,8 @@ static struct sk_buff *iavf_build_skb(struct iavf_ring *rx_ring,
 		return NULL;
 	/* prefetch first cache line of first page */
 	va = page_address(rx_buffer->page) + rx_buffer->page_offset;
-	prefetch(va);
-#if L1_CACHE_BYTES < 128
-	prefetch(va + L1_CACHE_BYTES);
-#endif
+	net_prefetch(va);
+
 	/* build an skb around the page buffer */
 	skb = build_skb(va - IAVF_SKB_PAD, truesize);
 	if (unlikely(!skb))
diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c
index 9d0d6b0025cf..d2fca4a52f51 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx.c
+++ b/drivers/net/ethernet/intel/ice/ice_txrx.c
@@ -919,10 +919,7 @@ ice_build_skb(struct ice_ring *rx_ring, struct ice_rx_buf *rx_buf,
 	 * likely have a consumer accessing first few bytes of meta
 	 * data, and then actual data.
 	 */
-	prefetch(xdp->data_meta);
-#if L1_CACHE_BYTES < 128
-	prefetch((void *)(xdp->data + L1_CACHE_BYTES));
-#endif
+	net_prefetch(xdp->data_meta);
 	/* build an skb around the page buffer */
 	skb = build_skb(xdp->data_hard_start, truesize);
 	if (unlikely(!skb))
@@ -964,10 +961,7 @@ ice_construct_skb(struct ice_ring *rx_ring, struct ice_rx_buf *rx_buf,
 	struct sk_buff *skb;
 
 	/* prefetch first cache line of first page */
-	prefetch(xdp->data);
-#if L1_CACHE_BYTES < 128
-	prefetch((void *)(xdp->data + L1_CACHE_BYTES));
-#endif /* L1_CACHE_BYTES */
+	net_prefetch(xdp->data);
 
 	/* allocate a skb to store the frags */
 	skb = __napi_alloc_skb(&rx_ring->q_vector->napi, ICE_RX_HDR_SIZE,
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 4f05f6efe6af..698bb6a4b088 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -8047,10 +8047,7 @@ static struct sk_buff *igb_construct_skb(struct igb_ring *rx_ring,
 	struct sk_buff *skb;
 
 	/* prefetch first cache line of first page */
-	prefetch(va);
-#if L1_CACHE_BYTES < 128
-	prefetch(va + L1_CACHE_BYTES);
-#endif
+	net_prefetch(va);
 
 	/* allocate a skb to store the frags */
 	skb = napi_alloc_skb(&rx_ring->q_vector->napi, IGB_RX_HDR_LEN);
@@ -8104,10 +8101,7 @@ static struct sk_buff *igb_build_skb(struct igb_ring *rx_ring,
 	struct sk_buff *skb;
 
 	/* prefetch first cache line of first page */
-	prefetch(va);
-#if L1_CACHE_BYTES < 128
-	prefetch(va + L1_CACHE_BYTES);
-#endif
+	net_prefetch(va);
 
 	/* build an skb around the page buffer */
 	skb = build_skb(va - IGB_SKB_PAD, truesize);
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 9593aa4eea36..c6968fdb6caa 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -1550,10 +1550,7 @@ static struct sk_buff *igc_build_skb(struct igc_ring *rx_ring,
 	struct sk_buff *skb;
 
 	/* prefetch first cache line of first page */
-	prefetch(va);
-#if L1_CACHE_BYTES < 128
-	prefetch(va + L1_CACHE_BYTES);
-#endif
+	net_prefetch(va);
 
 	/* build an skb around the page buffer */
 	skb = build_skb(va - IGC_SKB_PAD, truesize);
@@ -1589,10 +1586,7 @@ static struct sk_buff *igc_construct_skb(struct igc_ring *rx_ring,
 	struct sk_buff *skb;
 
 	/* prefetch first cache line of first page */
-	prefetch(va);
-#if L1_CACHE_BYTES < 128
-	prefetch(va + L1_CACHE_BYTES);
-#endif
+	net_prefetch(va);
 
 	/* allocate a skb to store the frags */
 	skb = napi_alloc_skb(&rx_ring->q_vector->napi, IGC_RX_HDR_LEN);
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 2f8a4cfc5fa1..f4f2198f388b 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -2095,10 +2095,8 @@ static struct sk_buff *ixgbe_construct_skb(struct ixgbe_ring *rx_ring,
 	struct sk_buff *skb;
 
 	/* prefetch first cache line of first page */
-	prefetch(xdp->data);
-#if L1_CACHE_BYTES < 128
-	prefetch(xdp->data + L1_CACHE_BYTES);
-#endif
+	net_prefetch(xdp->data);
+
 	/* Note, we get here by enabling legacy-rx via:
 	 *
 	 *    ethtool --set-priv-flags <dev> legacy-rx on
@@ -2161,10 +2159,7 @@ static struct sk_buff *ixgbe_build_skb(struct ixgbe_ring *rx_ring,
 	 * likely have a consumer accessing first few bytes of meta
 	 * data, and then actual data.
 	 */
-	prefetch(xdp->data_meta);
-#if L1_CACHE_BYTES < 128
-	prefetch(xdp->data_meta + L1_CACHE_BYTES);
-#endif
+	net_prefetch(xdp->data_meta);
 
 	/* build an skb to around the page buffer */
 	skb = build_skb(xdp->data_hard_start, truesize);
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index a428113e6d54..50afec43e001 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -866,10 +866,8 @@ struct sk_buff *ixgbevf_construct_skb(struct ixgbevf_ring *rx_ring,
 	struct sk_buff *skb;
 
 	/* prefetch first cache line of first page */
-	prefetch(xdp->data);
-#if L1_CACHE_BYTES < 128
-	prefetch(xdp->data + L1_CACHE_BYTES);
-#endif
+	net_prefetch(xdp->data);
+
 	/* Note, we get here by enabling legacy-rx via:
 	 *
 	 *    ethtool --set-priv-flags <dev> legacy-rx on
@@ -947,10 +945,7 @@ static struct sk_buff *ixgbevf_build_skb(struct ixgbevf_ring *rx_ring,
 	 * have a consumer accessing first few bytes of meta data,
 	 * and then actual data.
 	 */
-	prefetch(xdp->data_meta);
-#if L1_CACHE_BYTES < 128
-	prefetch(xdp->data_meta + L1_CACHE_BYTES);
-#endif
+	net_prefetch(xdp->data_meta);
 
 	/* build an skb around the page buffer */
 	skb = build_skb(xdp->data_hard_start, truesize);
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index b0e303f6603f..b8abe1d7aa0b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2193,6 +2193,22 @@ int netdev_get_num_tc(struct net_device *dev)
 	return dev->num_tc;
 }
 
+static inline void net_prefetch(void *p)
+{
+	prefetch(p);
+#if L1_CACHE_BYTES < 128
+	prefetch((u8 *)p + L1_CACHE_BYTES);
+#endif
+}
+
+static inline void net_prefetchw(void *p)
+{
+	prefetchw(p);
+#if L1_CACHE_BYTES < 128
+	prefetchw((u8 *)p + L1_CACHE_BYTES);
+#endif
+}
+
 void netdev_unbind_sb_channel(struct net_device *dev,
 			      struct net_device *sb_dev);
 int netdev_bind_sb_channel_queue(struct net_device *dev,
-- 
2.21.0

[PATCH net-next 2/3] net/mlx5e: RX, Add a prefetch command for small L1_CACHE_BYTES

[Tariq Toukan]

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>
---
 drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c    |  4 ++--
 drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c |  4 ++--
 drivers/net/ethernet/mellanox/mlx5/core/en_rx.c     | 13 ++++++-------
 .../net/ethernet/mellanox/mlx5/core/en_selftest.c   |  3 +--
 4 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
index 0e6946fc121f..4bcb73a5522f 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
@@ -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;
 
@@ -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++;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
index a33a1f762c70..786fedf52436 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
@@ -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);
@@ -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++;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index 65828af120b7..228fd775bcd5 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -30,7 +30,6 @@
  * SOFTWARE.
  */
 
-#include <linux/prefetch.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/tcp.h>
@@ -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);
@@ -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 =
@@ -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++;
@@ -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);
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_selftest.c b/drivers/net/ethernet/mellanox/mlx5/core/en_selftest.c
index 46790216ce86..ce8ab1f01876 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_selftest.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_selftest.c
@@ -30,7 +30,6 @@
  * SOFTWARE.
  */
 
-#include <linux/prefetch.h>
 #include <linux/ip.h>
 #include <linux/udp.h>
 #include <net/udp.h>
@@ -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  */
-- 
2.21.0

[PATCH net-next 3/3] net/mlx4_en: RX, Add a prefetch command for small L1_CACHE_BYTES

[Tariq Toukan]

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>
---
 drivers/net/ethernet/mellanox/mlx4/en_rx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
index b50c567ef508..99d7737e8ad6 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -705,7 +705,7 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
 
 		frags = ring->rx_info + (index << priv->log_rx_info);
 		va = page_address(frags[0].page) + frags[0].page_offset;
-		prefetchw(va);
+		net_prefetchw(va);
 		/*
 		 * make sure we read the CQE after we read the ownership bit
 		 */
-- 
2.21.0

Re: [PATCH net-next 3/3] net/mlx4_en: RX, Add a prefetch command for small L1_CACHE_BYTES

[Eric Dumazet]

On 8/26/20 5:54 AM, Tariq Toukan wrote:
> 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>
> ---
>  drivers/net/ethernet/mellanox/mlx4/en_rx.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> index b50c567ef508..99d7737e8ad6 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> @@ -705,7 +705,7 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
>  
>  		frags = ring->rx_info + (index << priv->log_rx_info);
>  		va = page_address(frags[0].page) + frags[0].page_offset;
> -		prefetchw(va);
> +		net_prefetchw(va);
>  		/*
>  		 * make sure we read the CQE after we read the ownership bit
>  		 */
> 

Why these cache lines would be written next ? Presumably we read the headers (pulled into skb->head)

Really using prefetch() for the about to be read packet is too late anyway for current cpus.

Re: [PATCH net-next 3/3] net/mlx4_en: RX, Add a prefetch command for small L1_CACHE_BYTES

[Saeed Mahameed]

On Wed, 2020-08-26 at 07:55 -0700, Eric Dumazet wrote:
> 
> On 8/26/20 5:54 AM, Tariq Toukan wrote:
> > 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>
> > ---
> >  drivers/net/ethernet/mellanox/mlx4/en_rx.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> > b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> > index b50c567ef508..99d7737e8ad6 100644
> > --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> > +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> > @@ -705,7 +705,7 @@ int mlx4_en_process_rx_cq(struct net_device
> > *dev, struct mlx4_en_cq *cq, int bud
> >  
> >  		frags = ring->rx_info + (index << priv->log_rx_info);
> >  		va = page_address(frags[0].page) +
> > frags[0].page_offset;
> > -		prefetchw(va);
> > +		net_prefetchw(va);
> >  		/*
> >  		 * make sure we read the CQE after we read the
> > ownership bit
> >  		 */
> > 
> 
> Why these cache lines would be written next ? Presumably we read the
> headers (pulled into skb->head)
> 

XDP

> Really using prefetch() for the about to be read packet is too late
> anyway for current cpus.
> 

Re: [PATCH net-next 0/3] net_prefetch API

[David Miller]

From: Tariq Toukan <tariqt@mellanox.com>
Date: Wed, 26 Aug 2020 15:54:15 +0300

> This patchset adds a common net API for L1 cacheline size-aware prefetch.
> 
> Patch 1 introduces the common API in net and aligns the drivers to use it.
> Patches 2 and 3 add usage in mlx4 and mlx5 Eth drivers.
> 
> Series generated against net-next commit:
> 079f921e9f4d Merge tag 'batadv-next-for-davem-20200824' of git://git.open-mesh.org/linux-merge

Effectively a nice little cleanup, series applied, thanks.