net: hns3: optimize the barrier using when cleaning TX BD

Currently, a barrier is used when cleaning each TX BD, which may
cause performance degradation.

This patch optimizes it to use one barrier when cleaning TX BD
each round.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 21eac68..25d607c 100644 (file)
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -2186,20 +2186,25 @@ static void hns3_reuse_buffer(struct hns3_enet_ring *ring, int i)
        ring->desc[i].rx.bd_base_info = 0;
 }
 
-static void hns3_nic_reclaim_one_desc(struct hns3_enet_ring *ring, int *bytes,
-                                     int *pkts)
+static void hns3_nic_reclaim_desc(struct hns3_enet_ring *ring, int head,
+                                 int *bytes, int *pkts)
 {
        int ntc = ring->next_to_clean;
        struct hns3_desc_cb *desc_cb;
 
-       desc_cb = &ring->desc_cb[ntc];
-       (*pkts) += (desc_cb->type == DESC_TYPE_SKB);
-       (*bytes) += desc_cb->length;
-       /* desc_cb will be cleaned, after hnae3_free_buffer_detach*/
-       hns3_free_buffer_detach(ring, ntc);
+       while (head != ntc) {
+               desc_cb = &ring->desc_cb[ntc];
+               (*pkts) += (desc_cb->type == DESC_TYPE_SKB);
+               (*bytes) += desc_cb->length;
+               /* desc_cb will be cleaned, after hnae3_free_buffer_detach */
+               hns3_free_buffer_detach(ring, ntc);
 
-       if (++ntc == ring->desc_num)
-               ntc = 0;
+               if (++ntc == ring->desc_num)
+                       ntc = 0;
+
+               /* Issue prefetch for next Tx descriptor */
+               prefetch(&ring->desc_cb[ntc]);
+       }
 
        /* This smp_store_release() pairs with smp_load_acquire() in
         * ring_space called by hns3_nic_net_xmit.
@@ -2244,11 +2249,7 @@ void hns3_clean_tx_ring(struct hns3_enet_ring *ring)
 
        bytes = 0;
        pkts = 0;
-       while (head != ring->next_to_clean) {
-               hns3_nic_reclaim_one_desc(ring, &bytes, &pkts);
-               /* Issue prefetch for next Tx descriptor */
-               prefetch(&ring->desc_cb[ring->next_to_clean]);
-       }
+       hns3_nic_reclaim_desc(ring, head, &bytes, &pkts);
 
        ring->tqp_vector->tx_group.total_bytes += bytes;
        ring->tqp_vector->tx_group.total_packets += pkts;