Re: [PATCH net v4 1/2] tun: bound the NAPI receive queue

[Antonio Quartulli <antonio@mandelbit.com>]

Hi,

On 06/11/2026 22:04, Willem de Bruijn wrote:
> This is quite a complex solution.

Yeah, I agree. Trying to address all concerns (including Sashiko's) got 
me a bit out of track.

> 
> Can we perhaps simplify it a bit? For instance:
> 
> On tx only keep the lockless check. Number of packets that can bypass
> that is bounded, by the number of competing threads.
> 
> On rx avoid the new queue, by not temporary presenting an empty queue:
> 
>          spin_lock(&queue->lock);
>          if (skb_queue_len(queue) <= budget) {
>              skb_queue_splice_tail_init(queue, &process_queue);
>          } else {
>              while (skb_queue_len(&process_queue) < budget &&
>                     (skb = __skb_dequeue(queue)))
>                  __skb_queue_tail(&process_queue, skb);
>          }
>          spin_unlock(&queue->lock);
> 

Ok, I get your point.
Let me spin another simplified version.

Cheers,

pw-bot: cr


-- 
Antonio Quartulli

CEO and Co-Founder
Mandelbit Srl
https://www.mandelbit.com