Re: [patch 37/44] xen: add virtual network device driver
From: Stephen Hemminger <hidden>
Date: 2007-07-17 08:47:19
+struct netfront_info {
+ struct list_head list;
+ struct net_device *netdev;
+
+ struct net_device_stats stats;There is now a net_device_stats element inside net_device on 2.6.21 or later.
+ + struct xen_netif_tx_front_ring tx; + struct xen_netif_rx_front_ring rx; + + spinlock_t tx_lock; + spinlock_t rx_lock;
It might be a performance advantage to reorder/align these structure elements to put transmit hot elements together, and put tx and rx on different cache lines?
+ unsigned int evtchn;
+
+ /* 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;
+
+ /*
+ * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
+ * are linked from tx_skb_freelist through skb_entry.link.
+ *
+ * NB. Freelist index entries are always going to be less than
+ * PAGE_OFFSET, whereas pointers to skbs will always be equal or
+ * greater than PAGE_OFFSET: we use this property to distinguish
+ * them.
+ */
+ union skb_entry {
+ struct sk_buff *skb;
+ unsigned link;
+ } tx_skbs[NET_TX_RING_SIZE];
+ grant_ref_t gref_tx_head;
+ grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
+ unsigned tx_skb_freelist;
+
+ 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];
+};