net/mlx4_en: Add __GFP_COLD gfp flags in alloc_pages

Needed in order to get cache cold pages (L3 flushed) for HW scatter.

Otherwise memory may flush those entries when the packet comes from
PCI, causing back pressure resulting in BW decrease.
Signed-off-by: NIdo Shamay <idos@mellanox.com>
Signed-off-by: NAmir Vadai <amirv@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/en_rx.c

@@ -156,7 +156,7 @@ static int mlx4_en_init_allocator(struct mlx4_en_priv *priv,
 		const struct mlx4_en_frag_info *frag_info = &priv->frag_info[i];
 
 		if (mlx4_alloc_pages(priv, &ring->page_alloc[i],
-				     frag_info, GFP_KERNEL))
+				     frag_info, GFP_KERNEL | __GFP_COLD))
 			goto out;
 	}
 	return 0;
@@ -268,7 +268,7 @@ static int mlx4_en_fill_rx_buffers(struct mlx4_en_priv *priv)
 
 			if (mlx4_en_prepare_rx_desc(priv, ring,
 						    ring->actual_size,
-						    GFP_KERNEL)) {
+						    GFP_KERNEL | __GFP_COLD)) {
 				if (ring->actual_size < MLX4_EN_MIN_RX_SIZE) {
 					en_err(priv, "Failed to allocate enough rx buffers\n");
 					return -ENOMEM;
@@ -635,7 +635,8 @@ static void mlx4_en_refill_rx_buffers(struct mlx4_en_priv *priv,
 	int index = ring->prod & ring->size_mask;
 
 	while ((u32) (ring->prod - ring->cons) < ring->actual_size) {
-		if (mlx4_en_prepare_rx_desc(priv, ring, index, GFP_ATOMIC))
+		if (mlx4_en_prepare_rx_desc(priv, ring, index,
+					    GFP_ATOMIC | __GFP_COLD))
 			break;
 		ring->prod++;
 		index = ring->prod & ring->size_mask;