On Wed, Sep 24, 2025 at 03:33:08PM +0800, Jason Wang wrote:

On Wed, Sep 24, 2025 at 3:18 PM Michael S. Tsirkin [off-list ref] wrote:

quoted

On Tue, Sep 23, 2025 at 12:15:45AM +0200, Simon Schippers wrote:

quoted

This patch series deals with TUN, TAP and vhost_net which drop incoming
SKBs whenever their internal ptr_ring buffer is full. Instead, with this
patch series, the associated netdev queue is stopped before this happens.
This allows the connected qdisc to function correctly as reported by [1]
and improves application-layer performance, see our paper [2]. Meanwhile
the theoretical performance differs only slightly:

About this whole approach.
What if userspace is not consuming packets?
Won't the watchdog warnings appear?
Is it safe to allow userspace to block a tx queue
indefinitely?

I think it's safe as it's a userspace device, there's no way to
guarantee the userspace can process the packet in time (so no watchdog
for TUN).

Thanks

Hmm. Anyway, I guess if we ever want to enable timeout for tun,
we can worry about it then. Does not need to block this patchset.

quoted

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MST