net/mlx4_en: Align tx path structures to cache lines

Reorganize struct mlx4_en_tx_ring to have:
- One cache line containing last_nr_txbb & cons & wake_queue, used by tx
  completion.
- One cache line containing fields dirtied by mlx4_en_xmit()
- Following part is read mostly and shared by cpus.

Align struct mlx4_en_tx_info to a cache line
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NAmir Vadai <amirv@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/mlx4_en.h

@@ -222,7 +222,7 @@ struct mlx4_en_tx_info {
 	u8		data_offset;
 	u8		inl;
 	u8		ts_requested;
-};
+} ____cacheline_aligned_in_smp;
 
 
 #define MLX4_EN_BIT_DESC_OWN	0x80000000
@@ -253,40 +253,46 @@ struct mlx4_en_rx_alloc {
 };
 
 struct mlx4_en_tx_ring {
+	/* cache line used and dirtied in tx completion
+	 * (mlx4_en_free_tx_buf())
+	 */
+	u32			last_nr_txbb;
+	u32			cons;
+	unsigned long		wake_queue;
+
+	/* cache line used and dirtied in mlx4_en_xmit() */
+	u32			prod ____cacheline_aligned_in_smp;
+	unsigned long		bytes;
+	unsigned long		packets;
+	unsigned long		tx_csum;
+	unsigned long		tso_packets;
+	unsigned long		xmit_more;
+	struct mlx4_bf		bf;
+	unsigned long		queue_stopped;
+
+	/* Following part should be mostly read */
+	cpumask_t		affinity_mask;
+	struct mlx4_qp		qp;
 	struct mlx4_hwq_resources wqres;
-	u32 size ; /* number of TXBBs */
+	u32			size; /* number of TXBBs */
 	u32			size_mask;
 	u16			stride;
 	u16			cqn;	/* index of port CQ associated with this ring */
-	u32 prod;
-	u32 cons;
 	u32			buf_size;
 	u32			doorbell_qpn;
 	void			*buf;
 	struct mlx4_en_tx_info	*tx_info;
 	u8			*bounce_buf;
-	u8 queue_index;
-	cpumask_t affinity_mask;
-	u32 last_nr_txbb;
-	struct mlx4_qp qp;
 	struct mlx4_qp_context	context;
 	int			qpn;
 	enum mlx4_qp_state	qp_state;
-	struct mlx4_srq dummy;
-	unsigned long bytes;
-	unsigned long packets;
-	unsigned long tx_csum;
-	unsigned long queue_stopped;
-	unsigned long wake_queue;
-	unsigned long tso_packets;
-	unsigned long xmit_more;
-	struct mlx4_bf bf;
+	u8			queue_index;
 	bool			bf_enabled;
 	bool			bf_alloced;
 	struct netdev_queue	*tx_queue;
 	int			hwtstamp_tx_type;
 	int			inline_thold;
-};
+} ____cacheline_aligned_in_smp;
 
 struct mlx4_en_rx_desc {
 	/* actual number of entries depends on rx ring stride */