Re: [PATCH 6/6] eventpoll: add support for min-wait

[Soheil Hassas Yeganeh]

On Thu, Dec 1, 2022 at 1:00 PM Jens Axboe <axboe@xxxxxxxxx> wrote:
>
> >>> @@ -1845,6 +1891,18 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
> >>>             ewq.timed_out = true;
> >>>     }
> >>>
> >>> +   /*
> >>> +    * If min_wait is set for this epoll instance, note the min_wait
> >>> +    * time. Ensure the lowest bit is set in ewq.min_wait_ts, that's
> >>> +    * the state bit for whether or not min_wait is enabled.
> >>> +    */
> >>> +   if (ep->min_wait_ts) {
> >>
> >> Can we limit this block to "ewq.timed_out && ep->min_wait_ts"?
> >> AFAICT, the code we run here is completely wasted if timeout is 0.
> >
> > Yep certainly, I can gate it on both of those conditions.
> Looking at this for a respin, I think it should be gated on
> !ewq.timed_out? timed_out == true is the path that it's wasted on
> anyway.

Ah, yes, that's a good point. The check should be !ewq.timed_out.

Thanks,
Soheil

> --
> Jens Axboe
>