Hi, Jiri On 2017/9/23 0:03, Jiri Pirko wrote: > Fri, Sep 22, 2017 at 04:11:51PM CEST, linyunsh...@huawei.com wrote: >> Hi, Jiri >> >>>> - if (!tc) { >>>> + if (if_running) { >>>> + (void)hns3_nic_net_stop(netdev); >>>> + msleep(100); >>>> + } >>>> + >>>> + ret = (kinfo->dcb_ops && kinfo->dcb_ops->>setup_tc) ? >>>> + kinfo->dcb_ops->setup_tc(h, tc, prio_tc) : ->EOPNOTSUPP; >> >>> This is most odd. Why do you call dcb_ops from >ndo_setup_tc callback? >>> Why are you mixing this together? prio->tc mapping >can be done >>> directly in dcbnl >> >> Here is what we do in dcb_ops->setup_tc: >> Firstly, if current tc num is different from the tc num >> that user provide, then we setup the queues for each >> tc. >> >> Secondly, we tell hardware the pri to tc mapping that >> the stack is using. In rx direction, our hardware need >> that mapping to put different packet into different tc' >> queues according to the priority of the packet, then >> rss decides which specific queue in the tc should the >> packet goto. >> >> By mixing, I suppose you meant why we need the >> pri to tc infomation? > > by mixing, I mean what I wrote. You are calling dcb_ops callback from > ndo_setup_tc callback. So you are mixing DCBNL subsystem and TC > subsystem. Why? Why do you need sch_mqprio? Why DCBNL is not enough for > all?
When using lldptool, dcbnl is involved. But when using tc qdisc, dcbbl is not involved, below is the a few key call graph in the kernel when tc qdisc cmd is executed. cmd: tc qdisc add dev eth0 root handle 1:0 mqprio num_tc 4 map 1 2 3 3 1 3 1 1 hw 1 call graph: rtnetlink_rcv_msg -> tc_modify_qdisc -> qdisc_create -> mqprio_init -> hns3_nic_setup_tc When hns3_nic_setup_tc is called, we need to know how many tc num and prio_tc mapping from the tc_mqprio_qopt which is provided in the paramter in the ndo_setup_tc function, and dcb_ops is the our hardware specific method to setup the tc related parameter to the hardware, so this is why we call dcb_ops callback in ndo_setup_tc callback. I hope this will answer your question, thanks for your time. > > > >> I hope I did not misunderstand your question, thanks >> for your time reviewing. > > . >