On Tue, Feb 02, 2010 at 01:48:51PM -0800, Shirley Ma wrote:
> Use detach buffers API in virtio to free unused buffers in send queue when shutting down
> virtio_net to avoid maintaining skb link list for each transmit packet.
>
> Signed-off-by: Shirley Ma <xma@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
> drivers/net/virtio_net.c | 26 ++++++++------------------
> 1 files changed, 8 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 9d8984a..8069c08 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -56,9 +56,6 @@ struct virtnet_info
> /* Host will merge rx buffers for big packets (shake it! shake it!) */
> bool mergeable_rx_bufs;
>
> - /* Send queue. */
> - struct sk_buff_head send;
> -
> /* Work struct for refilling if we run low on memory. */
> struct delayed_work refill;
>
> @@ -505,7 +502,6 @@ static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
>
> while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
> pr_debug("Sent skb %p\n", skb);
> - __skb_unlink(skb, &vi->send);
> vi->dev->stats.tx_bytes += skb->len;
> vi->dev->stats.tx_packets++;
> tot_sgs += skb_vnet_hdr(skb)->num_sg;
> @@ -588,15 +584,6 @@ again:
> }
> vi->svq->vq_ops->kick(vi->svq);
>
> - /*
> - * Put new one in send queue. You'd expect we'd need this before
> - * xmit_skb calls add_buf(), since the callback can be triggered
> - * immediately after that. But since the callback just triggers
> - * another call back here, normal network xmit locking prevents the
> - * race.
> - */
> - __skb_queue_head(&vi->send, skb);
> -
> /* Don't wait up for transmitted skbs to be freed. */
> skb_orphan(skb);
> nf_reset(skb);
> @@ -977,9 +964,6 @@ static int virtnet_probe(struct virtio_device *vdev)
> dev->features |= NETIF_F_HW_VLAN_FILTER;
> }
>
> - /* Initialize our empty send queue. */
> - skb_queue_head_init(&vi->send);
> -
> err = register_netdev(dev);
> if (err) {
> pr_debug("virtio_net: registering device failed\n");
> @@ -1016,6 +1000,12 @@ static void free_unused_bufs(struct virtnet_info *vi)
> {
> void *buf;
> while (1) {
> + buf = vi->svq->vq_ops->detach_unused_buf(vi->svq);
> + if (!buf)
> + break;
> + dev_kfree_skb(buf);
> + }
> + while (1) {
> buf = vi->rvq->vq_ops->detach_unused_buf(vi->rvq);
> if (!buf)
> break;
> @@ -1035,11 +1025,11 @@ static void __devexit virtnet_remove(struct virtio_device *vdev)
> /* Stop all the virtqueues. */
> vdev->config->reset(vdev);
>
> - /* Free our skbs in send queue, if any. */
> - __skb_queue_purge(&vi->send);
>
> unregister_netdev(vi->dev);
> cancel_delayed_work_sync(&vi->refill);
> +
> + /* Free unused buffers in both send and recv, if any. */
> free_unused_bufs(vi);
>
> vdev->config->del_vqs(vi->vdev);
>
>
> --
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