Commit a2b97651 authored by Yunsheng Lin's avatar Yunsheng Lin Committed by Zheng Zengkai
Browse files

net: hns3: use bounce buffer when rx page can not be reused 

mainline inclusion
from mainline-master
commit 99f6b5fb
category: feature
bugzilla: 173966
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=99f6b5fb5f63cf69c6e56bba8e5492c98c521a63



----------------------------------------------------------------------

Currently rx page will be reused to receive future packet when
the stack releases the previous skb quickly. If the old page
can not be reused, a new page will be allocated and mapped,
which comsumes a lot of cpu when IOMMU is in the strict mode,
especially when the application and irq/NAPI happens to run on
the same cpu.

So allocate a new frag to memcpy the data to avoid the costly
IOMMU unmapping/mapping operation, and add "frag_alloc_err"
and "frag_alloc" stats in "ethtool -S ethX" cmd.

The throughput improves above 50% when running single thread of
iperf using TCP when IOMMU is in strict mode and iperf shares the
same cpu with irq/NAPI(rx_copybreak = 2048 and mtu = 1500).

Signed-off-by: default avatarYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: default avatarGuangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Reviewed-by: default avatarYongxin Li <liyongxin1@huawei.com>
Signed-off-by: default avatarJunxin Chen <chenjunxin1@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 74e5f589

drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c

+2 −0
Original line number Diff line number Diff line
@@ -450,6 +450,7 @@ static const struct hns3_dbg_item rx_queue_info_items[] = { 
	{ "HEAD", 2 },

	{ "FBDNUM", 2 },

	{ "PKTNUM", 2 },

	{ "COPYBREAK", 2 },

	{ "RING_EN", 2 },

	{ "RX_RING_EN", 2 },

	{ "BASE_ADDR", 10 },
@@ -481,6 +482,7 @@ static void hns3_dump_rx_queue_info(struct hns3_enet_ring *ring, 


	sprintf(result[j++], "%6u", readl_relaxed(ring->tqp->io_base +

		HNS3_RING_RX_RING_PKTNUM_RECORD_REG));

	sprintf(result[j++], "%9u", ring->rx_copybreak);



	sprintf(result[j++], "%7s", readl_relaxed(ring->tqp->io_base +

		HNS3_RING_EN_REG) ? "on" : "off");

drivers/net/ethernet/hisilicon/hns3/hns3_enet.c

+23 −0
Original line number Diff line number Diff line
@@ -3552,6 +3552,28 @@ static void hns3_nic_reuse_page(struct sk_buff *skb, int i, 
		   hns3_page_size(ring)) {

		desc_cb->page_offset += truesize;

		desc_cb->reuse_flag = 1;

	} else if (frag_size <= ring->rx_copybreak) {

		void *frag = napi_alloc_frag(frag_size);



		if (unlikely(!frag)) {

			u64_stats_update_begin(&ring->syncp);

			ring->stats.frag_alloc_err++;

			u64_stats_update_end(&ring->syncp);



			hns3_rl_err(ring_to_netdev(ring),

				    "failed to allocate rx frag\n");

			goto out;

		}



		desc_cb->reuse_flag = 1;

		memcpy(frag, desc_cb->buf + frag_offset, frag_size);

		skb_add_rx_frag(skb, i, virt_to_page(frag),

				offset_in_page(frag), frag_size, frag_size);



		u64_stats_update_begin(&ring->syncp);

		ring->stats.frag_alloc++;

		u64_stats_update_end(&ring->syncp);

		return;

	}



out:
@@ -4620,6 +4642,7 @@ static void hns3_ring_get_cfg(struct hnae3_queue *q, struct hns3_nic_priv *priv, 
		ring = &priv->ring[q->tqp_index + queue_num];

		desc_num = priv->ae_handle->kinfo.num_rx_desc;

		ring->queue_index = q->tqp_index;

		ring->rx_copybreak = priv->rx_copybreak;

	}



	hnae3_set_bit(ring->flag, HNAE3_RING_TYPE_B, ring_type);

drivers/net/ethernet/hisilicon/hns3/hns3_enet.h

+4 −0
Original line number Diff line number Diff line
@@ -427,6 +427,8 @@ struct ring_stats { 
			u64 csum_complete;

			u64 rx_multicast;

			u64 non_reuse_pg;

			u64 frag_alloc_err;

			u64 frag_alloc;

		};

		__le16 csum;

	};
@@ -478,6 +480,7 @@ struct hns3_enet_ring { 
		/* for Rx ring */

		struct {

			u32 pull_len;   /* memcpy len for current rx packet */

			u32 rx_copybreak;

			u32 frag_num;

			/* first buffer address for current packet */

			unsigned char *va;
@@ -569,6 +572,7 @@ struct hns3_nic_priv { 
	struct hns3_enet_coalesce tx_coal;

	struct hns3_enet_coalesce rx_coal;

	u32 tx_copybreak;

	u32 rx_copybreak;

};



union l3_hdr_info {

drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c

+12 −0
Original line number Diff line number Diff line
@@ -71,6 +71,8 @@ static const struct hns3_stats hns3_rxq_stats[] = { 
	HNS3_TQP_STAT("csum_complete", csum_complete),

	HNS3_TQP_STAT("multicast", rx_multicast),

	HNS3_TQP_STAT("non_reuse_pg", non_reuse_pg),

	HNS3_TQP_STAT("frag_alloc_err", frag_alloc_err),

	HNS3_TQP_STAT("frag_alloc", frag_alloc),

};



#define HNS3_PRIV_FLAGS_LEN ARRAY_SIZE(hns3_priv_flags)
@@ -1610,6 +1612,9 @@ static int hns3_get_tunable(struct net_device *netdev, 
		/* all the tx rings have the same tx_copybreak */

		*(u32 *)data = priv->tx_copybreak;

		break;

	case ETHTOOL_RX_COPYBREAK:

		*(u32 *)data = priv->rx_copybreak;

		break;

	default:

		ret = -EOPNOTSUPP;

		break;
@@ -1633,6 +1638,13 @@ static int hns3_set_tunable(struct net_device *netdev, 
		for (i = 0; i < h->kinfo.num_tqps; i++)

			priv->ring[i].tx_copybreak = priv->tx_copybreak;



		break;

	case ETHTOOL_RX_COPYBREAK:

		priv->rx_copybreak = *(u32 *)data;



		for (i = h->kinfo.num_tqps; i < h->kinfo.num_tqps * 2; i++)

			priv->ring[i].rx_copybreak = priv->rx_copybreak;



		break;

	default:

		ret = -EOPNOTSUPP;