diff options
| -rw-r--r-- | sys/netinet/ipfw/dn_sched.h | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/sys/netinet/ipfw/dn_sched.h b/sys/netinet/ipfw/dn_sched.h index b1c1c8f..fe54b02 100644 --- a/sys/netinet/ipfw/dn_sched.h +++ b/sys/netinet/ipfw/dn_sched.h @@ -68,6 +68,18 @@ struct dn_alg { * enqueue enqueue packet 'm' on scheduler 's', queue 'q'. * q is NULL for !MULTIQUEUE. * Return 0 on success, 1 on drop (packet consumed anyways). + * Note that q should be interpreted only as a hint + * on the flow that the mbuf belongs to: while a + * scheduler will normally enqueue m into q, it is ok + * to leave q alone and put the mbuf elsewhere. + * This function is called in two cases: + * - when a new packet arrives to the scheduler; + * - when a scheduler is reconfigured. In this case the + * call is issued by the new_queue callback, with a + * non empty queue (q) and m pointing to the first + * mbuf in the queue. For this reason, the function + * should internally check for (m != q->mq.head) + * before calling dn_enqueue(). * * dequeue Called when scheduler instance 's' can * dequeue a packet. Return NULL if none are available. @@ -94,8 +106,15 @@ struct dn_alg { * * new_queue called to set the per-queue parameters, * e.g. S and F, adjust sum of weights in the parent, etc. - * If the queue has packets in it, add them to the scheduler - * as well. + * + * The new_queue callback is normally called from when + * creating a new queue. In some cases (such as a + * scheduler change or reconfiguration) it can be called + * with a non empty queue. In this case, the queue + * In case of non empty queue, the new_queue callback could + * need to call the enqueue function. In this case, + * the callback should eventually call enqueue() passing + * as m the first element in the queue. * * free_queue actions related to a queue removal, e.g. undo * all the above. If the queue has data in it, also remove |
