On Sun, Sep 14, 2008 at 03:31:35AM -0700, Alexander Duyck wrote:
...

What if we were to push the check for netif_tx_queue_stopped further down into
the qdisc layer so that the basic qdiscs such as pfifo_fast did their own peek
and in the event that a queue is stopped it just returned NULL and set a flag
bit?  Basically this would mimic how we are currently handling throttled
queues (TCQ_F_THROTTLED).  Then in turn each parent could do a check on skb ==
NULL and set the same flag, or they could act like multiq and just skip over
that leaf and move onto the next because it is stopped.

IMHO it's a very interesting idea. Probably it could be better
evaluated if we have any stats how much this reason of requeing is a
problem with mq devices.

On the other hand, I wondered about a possibility of rehashing to other
queues in some cases during requeuing, which would be impossible after
such change.

Thanks,
Jarek P.