netdev - Re: [PATCH net-next] bonding: 3ad: apply ad_actor settings changes immediately

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Date:	Wed, 3 Feb 2016 20:55:52 +0100
From:	Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
To:	Jay Vosburgh <jay.vosburgh@...onical.com>
Cc:	Nikolay Aleksandrov <razor@...ckwall.org>, netdev@...r.kernel.org,
	davem@...emloft.net, Veaceslav Falico <vfalico@...il.com>,
	Andy Gospodarek <gospo@...ulusnetworks.com>
Subject: Re: [PATCH net-next] bonding: 3ad: apply ad_actor settings changes
 immediately

On 02/03/2016 08:48 PM, Jay Vosburgh wrote:
> Nikolay Aleksandrov <nikolay@...ulusnetworks.com> wrote:
> 
>> On 02/03/2016 08:05 PM, Jay Vosburgh wrote:
>>> Nikolay Aleksandrov <razor@...ckwall.org> wrote:
>>>
>>>> From: Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
>>>>
>>>> Currently the bonding allows to set ad_actor_system and prio while the
>>>> bond device is down, but these are actually applied only if there aren't
>>>> any slaves yet (applied to bond device when first slave shows up, and to
>>>> slaves at 3ad bind time). After this patch changes are applied immediately
>>>> and the new values can be used/seen after the bond's upped so it's not
>>>> necessary anymore to release all and enslave again to see the changes.
>>>>
>>>> CC: Jay Vosburgh <j.vosburgh@...il.com>
>>>> CC: Veaceslav Falico <vfalico@...il.com>
>>>> CC: Andy Gospodarek <gospo@...ulusnetworks.com>
>>>> Signed-off-by: Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
>>>
>>> 	Looks good to me.
>>>
>>> Signed-off-by: Jay Vosburgh <jay.vosburgh@...onical.com>
>>>
>>> 	-J
>>>
>>
>> Thanks Jay. Do you think it makes sense to allow setting these while the
>> bond is up ? I don't see any serious problems.
> 
> 	Actually, I was thinking about that when I read the patch.
> 
> 	Changing these while live will trigger reselection of the
> aggregator(s), since selection information in the LACPDUs will change.
> It should just work itself out when the parter system sees the change.
> 
Yes, that was my thinking as well.

> 	E.g., if bonding received a LACPDU with a changed _prio or
> _system, __update_selected will clear AD_PORT_SELECTED if it doesn't
> match, and that will cascade through the state machine (in
> ad_mux_machine, COLLECTING_DISTRIBUTING state will revert to
> MUX_ATTACHED, which will clear COLL_DIST and go from there).
> 
> 	I think it may converge more quickly if bonding set ->ntt on the
> ports after the change to immediately send new LACPDUs (rather than
> waiting for the LACP timeout), but that's an optimization.  If the _prio
> or _system are set to the same values they had previously, this is
> harmless as the partner system shouldn't reselect if nothing in the
> LACPDU changed.
> 
Good point, will look into it.

> 	There's a similar optimization in bond_3ad_unbind_slave to send
> a LACPDU with AGGREGATION cleared to speed up the LACP processing on the
> partner system.
> 
> 	-J
> 
> ---
> 	-Jay Vosburgh, jay.vosburgh@...onical.com
> 

Okay then, I'll give it a try and will post a patch.

Thank you,
 Nik