Re: [RFC PATCH net-next 02/12] vhost_net: introduce vhost_exceeds_weight()

On 2018年05月22日 00:29, Jesse Brandeburg wrote:

On Mon, 21 May 2018 17:04:23 +0800 Jason wrote:

quoted

Signed-off-by: Jason Wang <redacted>
---
  drivers/vhost/net.c | 13 ++++++++-----
  1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 15d191a..de544ee 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c

@@ -479,6 +479,12 @@ static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter,
  	return len;
  }
  
+static bool vhost_exceeds_weight(int pkts, int total_len)
+{
+	return unlikely(total_len >= VHOST_NET_WEIGHT) ||
+	       unlikely(pkts >= VHOST_NET_PKT_WEIGHT);

I was going to say just one unlikely, but then the caller of this
function also says unlikely(vhost_exceeds...), so I think you should
just drop the unlikely statements here (both of them)

Ok.

quoted

+}
+
  /* Expects to be always run from workqueue - which acts as
   * read-size critical section for our kind of RCU. */
  static void handle_tx(struct vhost_net *net)

@@ -570,7 +576,6 @@ static void handle_tx(struct vhost_net *net)
  			msg.msg_control = NULL;
  			ubufs = NULL;
  		}
-

unrelated whitespace changes?

Yes.

Thanks

quoted

  		total_len += len;
  		if (total_len < VHOST_NET_WEIGHT &&
  		    !vhost_vq_avail_empty(&net->dev, vq) &&

@@ -600,8 +605,7 @@ static void handle_tx(struct vhost_net *net)
  		else
  			vhost_zerocopy_signal_used(net, vq);
  		vhost_net_tx_packet(net);
-		if (unlikely(total_len >= VHOST_NET_WEIGHT) ||
-		    unlikely(++sent_pkts >= VHOST_NET_PKT_WEIGHT)) {
+		if (unlikely(vhost_exceeds_weight(++sent_pkts, total_len))) {
  			vhost_poll_queue(&vq->poll);
  			break;
  		}

@@ -887,8 +891,7 @@ static void handle_rx(struct vhost_net *net)
  		if (unlikely(vq_log))
  			vhost_log_write(vq, vq_log, log, vhost_len);
  		total_len += vhost_len;
-		if (unlikely(total_len >= VHOST_NET_WEIGHT) ||
-		    unlikely(++recv_pkts >= VHOST_NET_PKT_WEIGHT)) {
+		if (unlikely(vhost_exceeds_weight(++recv_pkts, total_len))) {
  			vhost_poll_queue(&vq->poll);
  			goto out;
  		}

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