xen-netfront: rearrange netfront structure to separate tx and rx

Keep tx and rx elements separate on different cachelines to prevent
bouncing.
Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Acked-by: NJeff Garzik <jgarzik@pobox.com>
Cc: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

drivers/net/xen-netfront.c

@@ -74,22 +74,12 @@ struct netfront_info {
 
 	struct napi_struct napi;
 
-	struct xen_netif_tx_front_ring tx;
-	struct xen_netif_rx_front_ring rx;
-
-	spinlock_t   tx_lock;
-	spinlock_t   rx_lock;
-
 	unsigned int evtchn;
+	struct xenbus_device *xbdev;
 
-	/* Receive-ring batched refills. */
-#define RX_MIN_TARGET 8
-#define RX_DFL_MIN_TARGET 64
-#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
-	unsigned rx_min_target, rx_max_target, rx_target;
-	struct sk_buff_head rx_batch;
-
-	struct timer_list rx_refill_timer;
+	spinlock_t   tx_lock;
+	struct xen_netif_tx_front_ring tx;
+	int tx_ring_ref;
 
 	/*
 	 * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
@@ -108,14 +98,23 @@ struct netfront_info {
 	grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
 	unsigned tx_skb_freelist;
 
+	spinlock_t   rx_lock ____cacheline_aligned_in_smp;
+	struct xen_netif_rx_front_ring rx;
+	int rx_ring_ref;
+
+	/* Receive-ring batched refills. */
+#define RX_MIN_TARGET 8
+#define RX_DFL_MIN_TARGET 64
+#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
+	unsigned rx_min_target, rx_max_target, rx_target;
+	struct sk_buff_head rx_batch;
+
+	struct timer_list rx_refill_timer;
+
 	struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
 	grant_ref_t gref_rx_head;
 	grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
 
-	struct xenbus_device *xbdev;
-	int tx_ring_ref;
-	int rx_ring_ref;
-
 	unsigned long rx_pfn_array[NET_RX_RING_SIZE];
 	struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1];
 	struct mmu_update rx_mmu[NET_RX_RING_SIZE];