vsock/virtio: reduce credit update messages

In order to reduce the number of credit update messages,
we send them only when the space available seen by the
transmitter is less than VIRTIO_VSOCK_MAX_PKT_BUF_SIZE.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Stefano Garzarella 2019-07-30 17:43:31 +02:00 committed by David S. Miller
parent 473c7391ce
commit b89d882dc9
2 changed files with 14 additions and 3 deletions

View File

@ -41,6 +41,7 @@ struct virtio_vsock_sock {
/* Protected by rx_lock */
u32 fwd_cnt;
u32 last_fwd_cnt;
u32 rx_bytes;
struct list_head rx_queue;
};

View File

@ -211,6 +211,7 @@ static void virtio_transport_dec_rx_pkt(struct virtio_vsock_sock *vvs,
void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct virtio_vsock_pkt *pkt)
{
spin_lock_bh(&vvs->tx_lock);
vvs->last_fwd_cnt = vvs->fwd_cnt;
pkt->hdr.fwd_cnt = cpu_to_le32(vvs->fwd_cnt);
pkt->hdr.buf_alloc = cpu_to_le32(vvs->buf_alloc);
spin_unlock_bh(&vvs->tx_lock);
@ -261,6 +262,7 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
struct virtio_vsock_sock *vvs = vsk->trans;
struct virtio_vsock_pkt *pkt;
size_t bytes, total = 0;
u32 free_space;
int err = -EFAULT;
spin_lock_bh(&vvs->rx_lock);
@ -291,11 +293,19 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
virtio_transport_free_pkt(pkt);
}
}
free_space = vvs->buf_alloc - (vvs->fwd_cnt - vvs->last_fwd_cnt);
spin_unlock_bh(&vvs->rx_lock);
/* Send a credit pkt to peer */
virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_STREAM,
/* We send a credit update only when the space available seen
* by the transmitter is less than VIRTIO_VSOCK_MAX_PKT_BUF_SIZE
*/
if (free_space < VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) {
virtio_transport_send_credit_update(vsk,
VIRTIO_VSOCK_TYPE_STREAM,
NULL);
}
return total;