vhost-net: flush batched before enabling notifications

Commit 8c2e6b26ff ("vhost/net: Defer TX queue re-enable until after
sendmsg") tries to defer the notification enabling by moving the logic
out of the loop after the vhost_tx_batch() when nothing new is spotted.
This caused unexpected side effects as the new logic is reused for
several other error conditions.

A previous patch reverted 8c2e6b26ff. Now, bring the performance
back up by flushing batched buffers before enabling notifications.

Reported-by: Jon Kohler <jon@nutanix.com>
Cc: stable@vger.kernel.org
Fixes: 8c2e6b26ff ("vhost/net: Defer TX queue re-enable until after sendmsg")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20250917063045.2042-3-jasowang@redhat.com>
This commit is contained in:
Jason Wang 2025-09-17 14:30:45 +08:00 committed by Michael S. Tsirkin
parent 4174152771
commit e430451613
1 changed files with 5 additions and 0 deletions

View File

@ -780,6 +780,11 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock)
break; break;
/* Nothing new? Wait for eventfd to tell us they refilled. */ /* Nothing new? Wait for eventfd to tell us they refilled. */
if (head == vq->num) { if (head == vq->num) {
/* Flush batched packets to handle pending RX
* work (if busyloop_intr is set) and to avoid
* unnecessary virtqueue kicks.
*/
vhost_tx_batch(net, nvq, sock, &msg);
if (unlikely(busyloop_intr)) { if (unlikely(busyloop_intr)) {
vhost_poll_queue(&vq->poll); vhost_poll_queue(&vq->poll);
} else if (unlikely(vhost_enable_notify(&net->dev, } else if (unlikely(vhost_enable_notify(&net->dev,