[PATCH net-next v7 9/9] tun/tap & vhost-net: avoid ptr_ring tail-drop when qdisc is present
From: Simon Schippers <hidden>
Date: 2026-01-12 11:28:46
Also in:
kvm, lkml, virtualization
From: Simon Schippers <hidden>
Date: 2026-01-12 11:28:46
Also in:
kvm, lkml, virtualization
On 1/12/26 12:19, Michael S. Tsirkin wrote:
On Mon, Jan 12, 2026 at 12:17:12PM +0100, Simon Schippers wrote:quoted
On 1/12/26 05:33, Michael S. Tsirkin wrote:quoted
On Fri, Jan 09, 2026 at 11:14:54AM +0100, Simon Schippers wrote:quoted
Am I not allowed to stop the queue and then return NETDEV_TX_BUSY?We jump through a lot of hoops in virtio_net to avoid using NETDEV_TX_BUSY because that bypasses all the net/ cleverness. Given your patches aim to improve precisely ring full, I would say stopping proactively before NETDEV_TX_BUSY should be a priority.I already proactively stop here with the approach you proposed in the v6. Or am I missing something (apart from the xdp path)?Yes, I am just answering the general question you posed.
Ah okay.
quoted
And yes I also dislike returning NETDEV_TX_BUSY but I do not see how this can be prevented with lltx enabled.Preventing NETDEV_TX_BUSY 100% of the time is not required. It's there to handle races.
Great to know. Thanks