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>
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@ -307,8 +307,13 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
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spin_unlock_bh(&vvs->rx_lock);
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/* We send a credit update only when the space available seen
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* by the transmitter is less than VIRTIO_VSOCK_MAX_PKT_BUF_SIZE
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/* To reduce the number of credit update messages,
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* don't update credits as long as lots of space is available.
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* Note: the limit chosen here is arbitrary. Setting the limit
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* too high causes extra messages. Too low causes transmitter
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* stalls. As stalls are in theory more expensive than extra
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* messages, we set the limit to a high value. TODO: experiment
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* with different values.
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*/
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if (free_space < VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) {
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virtio_transport_send_credit_update(vsk,
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