Re: [RFC 3/3] mac80211: add ieee80211_reorder_txq

[Rajkumar Manoharan <rmanohar@codeaurora.org>]

On 2018-08-21 05:24, Toke Høiland-Jørgensen wrote:
> Rajkumar Manoharan <rmanohar@codeaurora.org> writes:
> 
>> This allows the driver to refill airtime fairness deficit
>> where the driver will not access txqs by ieee80211_next_txq.
>> In tx push mode data path, high priority txqs will be scheduled
>> for data transmission by ieee80211_next_txq and driver will not
>> prioritize txqs whereas in push-pull mode, the drivers can
>> prioritize txqs and access them directly. In such mode, airtime
>> deficit can not filled by ieee80211_next_txq.
>> 
[...]
> 
> This needs to check that the txq is currently at the head of
> local->active_txqs[txqi->txq.ac]; otherwise fairness enforcement 
> doesn't
> work. And with this check I'm not sure the reorder function is terribly
> useful for what you want to use it for?
> 
Hmm.. I tried to keep the same policy of next_txq(). i.e do not allow 
serving
txqs when the deficit is negative. reorder_txq() limits over serving the 
same
txq by driver. So that driver is given chance to serve other txqs.

As mentioned earlier, next_txq() can not be used for fetching txq 
directly.
So reorder_txq() needs to take care of refilling txq after serving them.

-Rajkumar