epoch and ath(4) - what should we be doing?

[Hans Petter Selasky]

On 2020-02-20 02:01, Adrian Chadd wrote:
> Questions:
> 
> * are these things recursive?

Yes.

> * what are the rules around sleeping? I've seen some ... discussions
> that were quite animated around this.

Any non-sleepable lock is allowed under EPOCH(9).

> * what should I be doing as an epoch tracker if I could call the
> receive routine from multiple paths. I see a few drivers have a single
> place where they're doing EPOCH_ENTER/EPOCH_EXIT using an epoch
> tracker allocated in the interrupt handler stack, but what if I also
> want to call that receive path from another function path too? Can I
> just stuff an epoch_tracker on the stack and it'll DTRT ?

Try:
https://reviews.freebsd.org/D23674

> * .. is there some updated doc or brain dump somewhere I can read? I'd
> like to go add this to a couple out of tree wifi drivers under
> development so this would make that whole thing much easier.

Gleb ???

--HPS