diff options
Diffstat (limited to 'lib/librte_vhost/virtio_net.c')
| -rw-r--r-- | lib/librte_vhost/virtio_net.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c index 337470d6..ea027f14 100644 --- a/lib/librte_vhost/virtio_net.c +++ b/lib/librte_vhost/virtio_net.c @@ -905,6 +905,8 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vring_desc *descs, "allocate memory for mbuf.\n"); return -1; } + if (unlikely(dev->dequeue_zero_copy)) + rte_mbuf_refcnt_update(cur, 1); prev->next = cur; prev->data_len = mbuf_offset; @@ -1056,9 +1058,21 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id, * 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. */ - if (unlikely(rte_atomic16_cmpset((volatile uint16_t *) - &dev->broadcast_rarp.cnt, 1, 0))) { + + if (unlikely(rte_atomic16_read(&dev->broadcast_rarp) && + rte_atomic16_cmpset((volatile uint16_t *) + &dev->broadcast_rarp.cnt, 1, 0))) { + rarp_mbuf = rte_pktmbuf_alloc(mbuf_pool); if (rarp_mbuf == NULL) { RTE_LOG(ERR, VHOST_DATA, |