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

From: Jens Axboe
Date: Thu Dec 01 2022 - 13:01:01 EST


>>> @@ -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.

--
Jens Axboe