Subject: Re: [RFC PATCH] sched: Fix resource limiting in pfifo_fast

From: Jarek Poplawski <[email-masked]>
Date: Sun, 30 Aug 2009 09:47:05 +0200

Eric Dumazet wrote, On 08/30/2009 08:54 AM:

> Krishna Kumar a écrit :
>> From: Krishna Kumar <[email-masked]>
>>
>> pfifo_fast_enqueue has this check:
>>         if (skb_queue_len(list) < qdisc_dev(qdisc)->tx_queue_len) {
>>
>> which allows each band to enqueue upto tx_queue_len skbs for a
>> total of 3*tx_queue_len skbs. I am not sure if this was the
>> intention of limiting in qdisc.
> 
> Yes I noticed that and said to myself :
> This was to let high priority packets have their own limit,
> independent on fact that low priority packets filled their queue.

Good point, but then logically it could be something like:
  if (skb_queue_len(list) < qdisc_dev(qdisc)->tx_queue_len / 3)

Of course, there is a backward compatibility question, plus
an sch_prio consistency question.

Jarek P.