Waskiewicz Jr, Peter P wrote: >>PJ Waskiewicz wrote: >> >>>+#ifdef CONFIG_NET_SCH_MULTIQUEUE >>>+ if (q->mq) >>>+ skb->queue_mapping = >>>+ >> >>q->prio2band[band&TC_PRIO_MAX]; >> >>>+ else >>>+ skb->queue_mapping = 0; >>>+#endif >> >> >>Setting it to zero here is wrong, consider: >> >>root qdisc: prio multiqueue >>child qdisc: prio non-multiqueue >> >>The top-level qdisc will set it, the child qdisc will unset it again. >>When multiqueue is inactive it should not touch it. >> >>I'll fix that as well. > > > But the child can't assume the device is multiqueue if the child is > non-multiqueue.
The child doesn't have to assume anything. > This is the same issue with IP forwarding, where if you > forward through a multiqueue device to a non-mq device, you don't know > if the destination device is multiqueue. No its not. I'm talking about nested qdiscs, which are all on a single device. > So the last qdisc to actually > dequeue into a device should have control what the queue mapping is. Fully agreed. And that is always the top-level qdisc. > If > a user had a multiqueue qdisc as root, and configured a child qdisc as > non-mq, that is a configuration error if the underlying device is indeed > multiqueue IMO. Absolutely not. First of all, its perfectly valid to use non-multiqueue qdiscs on multiqueue devices. Secondly, its only the root qdisc that has to know about multiqueue since that one controls the child qdiscs. Think about it, it makes absolutely no sense to have the child qdisc even know about multiqueue. Changing my example to have a multiqueue qdisc as child: root qdisc: 2 band prio multiqueue child qdisc of band 0: 2 band prio multiqueue When the root qdisc decides to dequeue band0, it checks whether subqueue 0 is active and dequeues the child qdisc. If the child qdisc is indeed another multiqueue qdisc as you suggest, if might decide to dequeue its own band 1 and checks that subqueue state. So where should the packet finally end up? And what if one of both subqueues is inactive? The only reasonable thing it can do is not care about multiqueue and just dequeue as usual. In fact I think it should be an error to configure multiqueue on a non-root qdisc. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
