Sat, Dec 15, 2018 at 11:45:25AM CET, yanmiaobest(a)gmail.com wrote:
>This is Miao, I am currently working on a project to implement a new team policy
>based on the kernel team support. Basically, I have lots of 'ports',
>each of them
>has a ID. I'd like to use the ID to calculate the hash and distribute
>the traffic to
>different team slave ports, similar to round-robin.
>And when looking into team code, I see the team kernel driver has
>the following comments:
> * Enable/disable port by adding to enabled port hashlist and setting
> * port->index (Might be racy so reader could see incorrect ifindex when
> * processing a flying packet, but that is not a problem). Write guarded
> * by team->lock.
>The team datapath runs lockless, and libteam can enable/disble port
>one the fly when traffic happens. For exmaple, I have 4 port and I
>port1->slave1, port2->slave2 and port3->slave3, when slave1 device is link
>down state, it becomes port0->slave0, port1->slave2, port2->slave3,
>using the ID%num as the hash function.
>But it seems if datapath runs lockless, it could see the wrong ifindex during
>configuration as stated in the comment because the team drvier needs to
>reconstruct the active ports list. So my question is why this is not a problem
>when datapathsees a wrong ifindex, wouldn't that break the defined team
>policy ? Thank you very much for your help.
Yes, it would. For a packet from time to time. Is it a problem?