From: Jakub Kicinski <redacted>
Date: Fri, 23 Oct 2015 19:58:11 +0100

+struct nfp_net_tx_buf {
+	struct sk_buff *skb;
+	dma_addr_t dma_addr;
+	short int fidx;
+	u16 pkt_cnt;
+	u32 real_len;
+};

This packs very poorly, and has a lot of padding holes.  Better ordering
would be:

struct nfp_net_tx_buf {
	struct sk_buff *skb;
	dma_addr_t dma_addr;
	u32 real_len;
	short int fidx;
	u16 pkt_cnt;
};

You really should audit the most core datastructures in this driver
for the same problem.