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SubjectRe: [PATCH] firmware: wake all waiters
Hi Luis!

On Wed, 28 Jun 2017, Luis R. Rodriguez wrote:

>On Wed, Jun 28, 2017 at 06:45:14AM -0700, Davidlohr Bueso wrote:
>> On Tue, 27 Jun 2017, Luis R. Rodriguez wrote:
>>
>> > diff --git a/include/linux/swait.h b/include/linux/swait.h
>> > index 4a4e180d0a35..14fcf23cece4 100644
>> > --- a/include/linux/swait.h
>> > +++ b/include/linux/swait.h
>> > @@ -29,7 +29,10 @@
>> > *
>> > * As a side effect of this; the data structures are slimmer.
>> > *
>> > - * One would recommend using this wait queue where possible.
>>
>> So I think this was added due to the smaller footprint and fewer
>> cycles that swait has compared to the traditional (bulkier)
>> waitqueues. While probably not worth it, I guess we could offer
>> super-simple waitqueues (sswait? :-) which do not have the rt caveats
>> and uses a regular spinlock. The wakeup_all() call would not drop
>> the lock upon every wakeup as we are stripping the waitqueue not
>> for determinism, but for overhead. To mitigate this, we might
>> also want to use wake_q for reduced hold q->lock hold times.
>>
>> But I don't think its worth yet another wait interface.
>> Alternatively, it crossed my mind we could also have wakeup_all()
>> use in the regular waitqueues, but I'd have to audit all the
>> current users to make sure we could actually do this.
>
>But this open-welcoming invite for swait then, should it go?

I have nothing against removing it.

Thanks,
Davidlohr

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