diff options
| author | Jason Wang <jasowang@redhat.com> | 2015-08-27 14:53:06 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-08-27 15:51:45 -0700 |
| commit | 547c890cfd26010e01b3faf98f29ca9b2252c8d8 (patch) | |
| tree | 9d4c1428dff69ecf799eeb0e313a72257551a3b1 | |
| parent | 5e0aa59728854837a7256e21644596f21a16ce0f (diff) | |
virtio-net: avoid unnecessary sg initialzation
Usually an skb does not have up to MAX_SKB_FRAGS frags. So no need to
initialize the unuse part of sg. This patch initialize the sg based on
the real number it will used:
- during xmit, it could be inferred from nr_frags and can_push.
- for small receive buffer, it will also be 2.
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/virtio_net.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 9b950f2db836..d8838dedb7a4 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -540,7 +540,7 @@ static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq, skb_put(skb, GOOD_PACKET_LEN); hdr = skb_vnet_hdr(skb); - sg_init_table(rq->sg, MAX_SKB_FRAGS + 2); + sg_init_table(rq->sg, 2); sg_set_buf(rq->sg, hdr, vi->hdr_len); skb_to_sgvec(skb, rq->sg + 1, 0, skb->len); @@ -893,7 +893,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) if (vi->mergeable_rx_bufs) hdr->num_buffers = 0; - sg_init_table(sq->sg, MAX_SKB_FRAGS + 2); + sg_init_table(sq->sg, skb_shinfo(skb)->nr_frags + (can_push ? 1 : 2)); if (can_push) { __skb_push(skb, hdr_len); num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len); |