On 02/19/2019 07:53 PM, Jesper Dangaard Brouer wrote: > The skb->queue_mapping already have read access, via __sk_buff->queue_mapping. > > This patch allow BPF tc qdisc clsact write access to the queue_mapping via > tc_cls_act_is_valid_access. Also handle that the value NO_QUEUE_MAPPING > is not allowed. > > It is already possible to change this via TC filter action skbedit > tc-skbedit(8). Due to the lack of TC examples, lets show one: > > # tc qdisc add dev ixgbe1 clsact > # tc filter add dev ixgbe1 ingress matchall action skbedit queue_mapping 5 > # tc filter list dev ixgbe1 ingress > > The most common mistake is that XPS (Transmit Packet Steering) takes > precedence over setting skb->queue_mapping. XPS is configured per DEVICE > via /sys/class/net/DEVICE/queues/tx-*/xps_cpus via a CPU hex mask. To > disable set mask=00. > > The purpose of changing skb->queue_mapping is to influence the selection of > the net_device "txq" (struct netdev_queue), which influence selection of > the qdisc "root_lock" (via txq->qdisc->q.lock) and txq->_xmit_lock. When > using the MQ qdisc the txq->qdisc points to different qdiscs and associated > locks, and HARD_TX_LOCK (txq->_xmit_lock), allowing for CPU scalability. > > Due to lack of TC examples, lets show howto attach clsact BPF programs: > > # tc qdisc add dev ixgbe2 clsact > # tc filter add dev ixgbe2 egress bpf da obj XXX_kern.o sec tc_qmap2cpu > # tc filter list dev ixgbe2 egress > > Signed-off-by: Jesper Dangaard Brouer <bro...@redhat.com>
Applied, thanks!
