Re: [PATCHv3 net-next] bonding: 3ad: send ifinfo notify when mux state changed

On 28/06/2024 06:10, Hangbin Liu wrote:

On Thu, Jun 27, 2024 at 07:24:10AM -0700, Jay Vosburgh wrote:

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Hangbin Liu [off-list ref] wrote:

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Ah.. Yes, that's a sad fact :(

	There are basically two paths that will change the LACP state
that's passed up via netlink (the aggregator ID, and actor and partner
oper port states): bond_3ad_state_machine_handler(), or incoming
LACPDUs, which call into ad_rx_machine().  Administrative changes to the

Ah, thanks, I didn't notice this. I will also enable lacp notify
in ad_rx_machine().

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bond will do it too, like adding or removing interfaces, but those
originate in user space and aren't happening asynchronously.

	If you want (almost) absolute reliability in communicating every
state change for the state machine and LACPDU processing, I think you'd
have to (a) create an object with the changed state, (b) queue it
somewhere, then (c) call a workqueue event to process that queue out of
line.

Hmm... This looks too complex. If we store all the states. A frequent flashing
may consume the memory. If we made a limit for the queue, we may still loosing
some state changes.

I'm not sure which way is better.

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It all depends on what are the requirements.

An uglier but lockless alternative would be to poll the slave's sysfs oper state,
that doesn't require any locks and would be up-to-date.

Hmm, that's a workaround, but the admin need to poll the state frequently as
they don't know when the state will change.

Hi Jay, are you OK to add this sysfs in bonding?

	I think what Nik is proposing is for your userspace to poll the
/sys/class/net/${DEV}/operstate.

Actually I was talking about:
 /sys/class/net/<bond port>/bonding_slave/ad_actor_oper_port_state
 /sys/class/net/<bond port>/bonding_slave/ad_partner_oper_port_state
etc

Wouldn't these work for you?

OK. There are 2 scenarios I got.

1) the local user want to get the local/partner state and make sure not
send pkts before they are in DISTRIBUTING state to avoid pkts drop, Or vice
versa. Only checking link operstate or up/down status is not enough.

2) the admin want to get the switch/partner status via LACP status incase
the switch is crashed.

Do you have any suggestion for the implementation?

Thanks
Hangbin