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Commit efecfd5f authored by Tony Nguyen's avatar Tony Nguyen Committed by Jeff Kirsher
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ixgbevf: Delay tail write for XDP packets 



Current XDP implementation hits the tail on every XDP_TX; change the
driver to only hit the tail after packet processing is complete.

Based on
commit 7379f97a ("ixgbe: delay tail write to every 'n' packets")

Signed-off-by: default avatarTony Nguyen <anthony.l.nguyen@intel.com>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Tested-by: default avatarAndrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent 21092e9c

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c

+18 −12
Original line number Diff line number Diff line
@@ -1016,14 +1016,8 @@ static int ixgbevf_xmit_xdp_ring(struct ixgbevf_ring *ring, 
			cpu_to_le32((len << IXGBE_ADVTXD_PAYLEN_SHIFT) |

				    IXGBE_ADVTXD_CC);



	/* Force memory writes to complete before letting h/w know there

	 * are new descriptors to fetch.  (Only applicable for weak-ordered

	 * memory model archs, such as IA-64).

	 *

	 * We also need this memory barrier to make certain all of the

	 * status bits have been updated before next_to_watch is written.

	 */

	wmb();

	/* Avoid any potential race with cleanup */

	smp_wmb();



	/* set next_to_watch value indicating a packet is present */

	i++;
@@ -1033,8 +1027,6 @@ static int ixgbevf_xmit_xdp_ring(struct ixgbevf_ring *ring, 
	tx_buffer->next_to_watch = tx_desc;

	ring->next_to_use = i;



	/* notify HW of packet */

	ixgbevf_write_tail(ring, i);

	return IXGBEVF_XDP_TX;

}
@@ -1101,6 +1093,7 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector, 
	struct ixgbevf_adapter *adapter = q_vector->adapter;

	u16 cleaned_count = ixgbevf_desc_unused(rx_ring);

	struct sk_buff *skb = rx_ring->skb;

	bool xdp_xmit = false;

	struct xdp_buff xdp;



	xdp.rxq = &rx_ring->xdp_rxq;
@@ -1142,11 +1135,13 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector, 
		}



		if (IS_ERR(skb)) {

			if (PTR_ERR(skb) == -IXGBEVF_XDP_TX)

			if (PTR_ERR(skb) == -IXGBEVF_XDP_TX) {

				xdp_xmit = true;

				ixgbevf_rx_buffer_flip(rx_ring, rx_buffer,

						       size);

			else

			} else {

				rx_buffer->pagecnt_bias++;

			}

			total_rx_packets++;

			total_rx_bytes += size;

		} else if (skb) {
@@ -1208,6 +1203,17 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector, 
	/* place incomplete frames back on ring for completion */

	rx_ring->skb = skb;



	if (xdp_xmit) {

		struct ixgbevf_ring *xdp_ring =

			adapter->xdp_ring[rx_ring->queue_index];



		/* Force memory writes to complete before letting h/w

		 * know there are new descriptors to fetch.

		 */

		wmb();

		ixgbevf_write_tail(xdp_ring, xdp_ring->next_to_use);

	}



	u64_stats_update_begin(&rx_ring->syncp);

	rx_ring->stats.packets += total_rx_packets;

	rx_ring->stats.bytes += total_rx_bytes;