From: Tariq Toukan <tariqt@mellanox.com>
Date: Wed, 16 May 2018 10:46:57 +0300
Subject: net/mlx5e: RX, Prefetch the xdp_frame data area
Patch-mainline: v4.19-rc1
Git-commit: d3398a4f1887eee46c22b37f6245faa6c51b130b
References: bsc#1103990 FATE#326006

A loaded XDP program might write to the xdp_frame data area,
prefetchw() it to avoid a potential cache miss.

Performance tests:
ConnectX-5, XDP_TX packet rate, single ring.
CPU: Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz

Before: 13,172,976 pps
After:  13,456,248 pps
2% gain.

Fixes: 22f453988194 ("net/mlx5e: Support XDP over Striding RQ")
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_rx.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -1099,6 +1099,7 @@ mlx5e_skb_from_cqe_mpwrq_linear(struct m
 
 	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);
 
 	rcu_read_lock();