[Make-wifi-fast] [PATCH v2 1/4] mac80211: Rearrange ieee80211_tx_info to make room for tx_time_est

Toke Høiland-Jørgensen toke at redhat.com
Fri Oct 18 10:22:14 EDT 2019

Johannes Berg <johannes at sipsolutions.net> writes:

> On Fri, 2019-10-18 at 16:01 +0200, Toke Høiland-Jørgensen wrote:
>> Right. Well in that case, let's try it. As long as we fail in a
>> reasonable way, we can just see if we run into anything that breaks? I
>> guess in this case that means rejecting requests from userspace if we
>> run out of IDs rather than silently wrapping and returning wrong data :)
> We can't reject due to how this works, but if the idr_alloc() fails then
> we'll just not give a status back to userspace later.

OK, I guess someone will notice if that suddenly starts happening all
the time ;)

>> > > We could also split 5/11. That would support up to 32 ACK IDs, and we
>> > > can just truncate the airtime at 2048 us, which is not a big deal I'd
>> > > say.
>> > 
>> > We can also play with the units of the airtime, e.g. making that a
>> > multiple of 2 or 4 us? Seems unlikely to matter much?
>> Sure, that's a good point! Increments of 4us means we can fit 4ms is 10
>> bits, leaving plenty of space for ACK IDs (hopefully).
>> I'll rework the series to use that instead :)
> OK.
> There are two places that call idr_alloc() with a hardcoded limit of
> 0x10000, you'll have to fix those to have the right limit according to
> the bits you leave for the ACK id.

Yup, found those. Will send a new version of the series in a bit.


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