net: e1000e: support txtd update delay via xmit_more
Don't update Tx tail descriptor if queue hasn't been stopped
and we know at least one more skb will be sent right away.
Signed-off-by: Florian Westphal <fw@strlen.de>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index aa39a81..1e8c40f 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -5444,16 +5444,6 @@
wmb();
tx_ring->next_to_use = i;
-
- if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA)
- e1000e_update_tdt_wa(tx_ring, i);
- else
- writel(i, tx_ring->tail);
-
- /* we need this if more than one processor can write to our tail
- * at a time, it synchronizes IO on IA64/Altix systems
- */
- mmiowb();
}
#define MINIMUM_DHCP_PACKET_SIZE 282
@@ -5655,6 +5645,21 @@
(MAX_SKB_FRAGS *
DIV_ROUND_UP(PAGE_SIZE,
adapter->tx_fifo_limit) + 2));
+
+ if (!skb->xmit_more ||
+ netif_xmit_stopped(netdev_get_tx_queue(netdev, 0))) {
+ if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA)
+ e1000e_update_tdt_wa(tx_ring,
+ tx_ring->next_to_use);
+ else
+ writel(tx_ring->next_to_use, tx_ring->tail);
+
+ /* we need this if more than one processor can write
+ * to our tail at a time, it synchronizes IO on
+ *IA64/Altix systems
+ */
+ mmiowb();
+ }
} else {
dev_kfree_skb_any(skb);
tx_ring->buffer_info[first].time_stamp = 0;