Commit 2bcb4b0f authored by Lennert Buytenhek's avatar Lennert Buytenhek Committed by David S. Miller
Browse files

mv643xx_eth: hook up skb recycling 



This gives a nice increase in the maximum loss-free packet forwarding
rate in routing workloads.

Signed-off-by: default avatarLennert Buytenhek <buytenh@marvell.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 04a4bb55

drivers/net/mv643xx_eth.c

+45 −21
Original line number Diff line number Diff line
@@ -370,6 +370,9 @@ struct mv643xx_eth_private { 
	u8 work_rx_refill;

	u8 work_rx_oom;



	int skb_size;

	struct sk_buff_head rx_recycle;



	/*

	 * RX state.

	 */
@@ -566,31 +569,19 @@ static int rxq_process(struct rx_queue *rxq, int budget) 
static int rxq_refill(struct rx_queue *rxq, int budget)

{

	struct mv643xx_eth_private *mp = rxq_to_mp(rxq);

	int skb_size;

	int refilled;



	/*

	 * Reserve 2+14 bytes for an ethernet header (the hardware

	 * automatically prepends 2 bytes of dummy data to each

	 * received packet), 16 bytes for up to four VLAN tags, and

	 * 4 bytes for the trailing FCS -- 36 bytes total.

	 */

	skb_size = rxq_to_mp(rxq)->dev->mtu + 36;



	/*

	 * Make sure that the skb size is a multiple of 8 bytes, as

	 * the lower three bits of the receive descriptor's buffer

	 * size field are ignored by the hardware.

	 */

	skb_size = (skb_size + 7) & ~7;



	refilled = 0;

	while (refilled < budget && rxq->rx_desc_count < rxq->rx_ring_size) {

		struct sk_buff *skb;

		int unaligned;

		int rx;



		skb = dev_alloc_skb(skb_size + dma_get_cache_alignment() - 1);

		skb = __skb_dequeue(&mp->rx_recycle);

		if (skb == NULL)

			skb = dev_alloc_skb(mp->skb_size +

					    dma_get_cache_alignment() - 1);



		if (skb == NULL) {

			mp->work_rx_oom |= 1 << rxq->index;

			goto oom;
@@ -608,8 +599,8 @@ static int rxq_refill(struct rx_queue *rxq, int budget) 
			rxq->rx_used_desc = 0;



		rxq->rx_desc_area[rx].buf_ptr = dma_map_single(NULL, skb->data,

						skb_size, DMA_FROM_DEVICE);

		rxq->rx_desc_area[rx].buf_size = skb_size;

						mp->skb_size, DMA_FROM_DEVICE);

		rxq->rx_desc_area[rx].buf_size = mp->skb_size;

		rxq->rx_skb[rx] = skb;

		wmb();

		rxq->rx_desc_area[rx].cmd_sts = BUFFER_OWNED_BY_DMA |
@@ -904,9 +895,15 @@ static int txq_reclaim(struct tx_queue *txq, int budget, int force) 
				       desc->byte_cnt, DMA_TO_DEVICE);

		}



		if (skb)

		if (skb != NULL) {

			if (skb_queue_len(&mp->rx_recycle) <

					mp->default_rx_ring_size &&

			    skb_recycle_check(skb, mp->skb_size))

				__skb_queue_head(&mp->rx_recycle, skb);

			else

				dev_kfree_skb(skb);

		}

	}



	__netif_tx_unlock(nq);
@@ -2042,6 +2039,26 @@ static void set_tx_coal(struct mv643xx_eth_private *mp, unsigned int delay) 
	wrl(mp, TX_FIFO_URGENT_THRESHOLD(mp->port_num), (coal & 0x3fff) << 4);

}



static void mv643xx_eth_recalc_skb_size(struct mv643xx_eth_private *mp)

{

	int skb_size;



	/*

	 * Reserve 2+14 bytes for an ethernet header (the hardware

	 * automatically prepends 2 bytes of dummy data to each

	 * received packet), 16 bytes for up to four VLAN tags, and

	 * 4 bytes for the trailing FCS -- 36 bytes total.

	 */

	skb_size = mp->dev->mtu + 36;



	/*

	 * Make sure that the skb size is a multiple of 8 bytes, as

	 * the lower three bits of the receive descriptor's buffer

	 * size field are ignored by the hardware.

	 */

	mp->skb_size = (skb_size + 7) & ~7;

}



static int mv643xx_eth_open(struct net_device *dev)

{

	struct mv643xx_eth_private *mp = netdev_priv(dev);
@@ -2061,8 +2078,12 @@ static int mv643xx_eth_open(struct net_device *dev) 


	init_mac_tables(mp);



	mv643xx_eth_recalc_skb_size(mp);



	napi_enable(&mp->napi);



	skb_queue_head_init(&mp->rx_recycle);



	for (i = 0; i < mp->rxq_count; i++) {

		err = rxq_init(mp, i);

		if (err) {
@@ -2158,6 +2179,8 @@ static int mv643xx_eth_stop(struct net_device *dev) 
	mv643xx_eth_get_stats(dev);

	mib_counters_update(mp);



	skb_queue_purge(&mp->rx_recycle);



	for (i = 0; i < mp->rxq_count; i++)

		rxq_deinit(mp->rxq + i);

	for (i = 0; i < mp->txq_count; i++)
@@ -2184,6 +2207,7 @@ static int mv643xx_eth_change_mtu(struct net_device *dev, int new_mtu) 
		return -EINVAL;



	dev->mtu = new_mtu;

	mv643xx_eth_recalc_skb_size(mp);

	tx_set_rate(mp, 1000000000, 16777216);



	if (!netif_running(dev))