1 files changed, 11 insertions, 0 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 2af89b662ca..cd547d04a8c 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -470,6 +470,10 @@ struct netdev_queue {
  */
         spinlock_t              _xmit_lock ____cacheline_aligned_in_smp;
         int                     xmit_lock_owner;
+        /*
+         * please use this field instead of dev->trans_start
+         */
+        unsigned long           trans_start;
 } ____cacheline_aligned_in_smp;
 
 
@@ -819,6 +823,11 @@ struct net_device
  * One part is mostly used on xmit path (device)
  */
         /* These may be needed for future network-power-down code. */
+
+        /*
+         * trans_start here is expensive for high speed devices on SMP,
+         * please use netdev_queue->trans_start instead.
+         */
         unsigned long           trans_start;    /* Time (in jiffies) of last Tx */
 
         int                     watchdog_timeo; /* used by dev_watchdog() */
@@ -1541,6 +1550,8 @@ static inline int netif_carrier_ok(const struct net_device *dev)
         return !test_bit(__LINK_STATE_NOCARRIER, &dev->state);
 }
 
+extern unsigned long dev_trans_start(struct net_device *dev);
+
 extern void __netdev_watchdog_up(struct net_device *dev);
 
 extern void netif_carrier_on(struct net_device *dev);