Re: [PATCH 0/6] Add qdisc->ops->peek() support.
From: Patrick McHardy <hidden>
Date: 2008-10-17 12:33:29
Jarek Poplawski wrote:
quoted hunk ↗ jump to hunk
Patrick McHardy wrote, On 10/16/2008 02:38 PM:quoted
Jarek Poplawski wrote:...quoted
quoted
PS: after this patchset only netem_enqueue() needs qdisc->requeue(), but I hope this won't take too long.Assuming work-conserving qdiscs are used with netem, the currently code will always send out a reorder packet immediately. This behaviour is trivial to implement without ->requeue. The problematic case is non-work-conserving inner qdiscs, but that doesn't seem important at all since you'd usually add it as parent of netem, which still works.How about something like this (example only)?@@ -233,7 +233,9 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch) */ cb->time_to_send = psched_get_time(); q->counter = 0; - ret = q->qdisc->ops->requeue(skb, q->qdisc); + q->qdisc->flags |= TCQ_F_REQUEUE; + ret = qdisc_equeue(skb, q->qdisc); + q->qdisc->flags &= ~TCQ_F_REQUEUE;
Well, the inner qdisc would still need to logic to order packets apprioriately. Its probably not that hard, but as I said, I don't think its necessary at all. It only makes a difference with a non-work-conserving inner qdisc, but a lot of the functionality of netem requires the inner tfifo anyways and rate-limiting is usually done on top of netem. So I would suggest so either hard-wire the tfifo qdisc or at least make the assumption that inner qdiscs are work-conserving.