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vsock/virtio: a better comment on credit update 

The comment we have is just repeating what the code does.
Include the *reason* for the condition instead.

Cc: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Michael S. Tsirkin 2019-09-03 03:38:16 -04:00 committed by David S. Miller
parent 9c895c1bc5
commit f4d7c8e3da
1 changed files with 7 additions and 2 deletions
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9
net/vmw_vsock/virtio_transport_common.c
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@ -307,8 +307,13 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
spin_unlock_bh(&vvs->rx_lock);
/* We send a credit update only when the space available seen
* by the transmitter is less than VIRTIO_VSOCK_MAX_PKT_BUF_SIZE
/* To reduce the number of credit update messages,
* don't update credits as long as lots of space is available.
* Note: the limit chosen here is arbitrary. Setting the limit
* too high causes extra messages. Too low causes transmitter
* stalls. As stalls are in theory more expensive than extra
* messages, we set the limit to a high value. TODO: experiment
* with different values.
*/
if (free_space < VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) {
virtio_transport_send_credit_update(vsk,