From e430451613c7a27beeadd00d707bcf7ceec6328e Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Wed, 17 Sep 2025 14:30:45 +0800 Subject: [PATCH] vhost-net: flush batched before enabling notifications Commit 8c2e6b26ffe2 ("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 8c2e6b26ffe2. Now, bring the performance back up by flushing batched buffers before enabling notifications. Reported-by: Jon Kohler Cc: stable@vger.kernel.org Fixes: 8c2e6b26ffe2 ("vhost/net: Defer TX queue re-enable until after sendmsg") Signed-off-by: Jason Wang Signed-off-by: Michael S. Tsirkin Message-Id: <20250917063045.2042-3-jasowang@redhat.com> --- drivers/vhost/net.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 57efd5c55f89e..35ded43304319 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -780,6 +780,11 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock) break; /* Nothing new? Wait for eventfd to tell us they refilled. */ 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)) { vhost_poll_queue(&vq->poll); } else if (unlikely(vhost_enable_notify(&net->dev, -- 2.47.3