On 07/04/2018 08:51 AM, Tiwei Bie wrote:
On Mon, Jul 02, 2018 at 10:16:21AM +0200, Maxime Coquelin wrote:
[...]
+
+ if (unlikely(vq->access_ok == 0))
+ if (unlikely(vring_translate(dev, vq) < 0))
+ goto out;
+
+
Please just keep one blank line.
+ /*
+ * Construct a RARP broadcast packet, and inject it to the "pkts"
+ * array, to looks like that guest actually send such packet.
+ *
+ * Check user_send_rarp() for more information.
+ *
+ * broadcast_rarp shares a cacheline in the virtio_net structure
+ * with some fields that are accessed during enqueue and
+ * rte_atomic16_cmpset() causes a write if using cmpxchg. This could
+ * result in false sharing between enqueue and dequeue.
+ *
+ * Prevent unnecessary false sharing by reading broadcast_rarp first
+ * and only performing cmpset if the read indicates it is likely to
+ * be set.
+ */
+
Please remove above blank line.
+ if (unlikely(rte_atomic16_read(&dev->broadcast_rarp) &&
+ rte_atomic16_cmpset((volatile uint16_t *)
+ &dev->broadcast_rarp.cnt, 1, 0))) {
+
+ rarp_mbuf = rte_net_make_rarp_packet(mbuf_pool, &dev->mac);
+ if (rarp_mbuf == NULL) {
+ RTE_LOG(ERR, VHOST_DATA,
+ "Failed to make RARP packet.\n");
+ return 0;
+ }
+ count -= 1;
+ }
+
+ count = virtio_dev_tx_split(dev, vq, mbuf_pool, pkts, count);
+
out:
if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
vhost_user_iotlb_rd_unlock(vq);
@@ -1200,10 +1222,10 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
* Inject it to the head of "pkts" array, so that switch's mac
* learning table will get updated first.
*/
- memmove(&pkts[1], pkts, i * sizeof(struct rte_mbuf *));
+ memmove(&pkts[1], pkts, count * sizeof(struct rte_mbuf *));
pkts[0] = rarp_mbuf;
- i += 1;
+ count += 1;
}
- return i;
+ return count;
}
--
2.14.4
Done,
Thanks,
Maxime
