On Sun, 2018-12-09 at 07:36 -0700, Jens Axboe wrote:
> On 12/9/18 3:02 AM, Benny Halevy wrote:
> > > +static int __aio_iopoll_check(struct kioctx *ctx, struct io_event __user *event,
> > > + unsigned int *nr_events, long min_nr, long max_nr)
> > > +{
> > > + int ret = 0;
> > > +
> > > + while (!*nr_events || !need_resched()) {
> >
> > Hmm, it doesn't make sense to spin in this loop
> > if the user got _all_ the events he requested, even
> > if !need_resched(). How about:
> >
> > while (!*nr_events || (!need_resched() && *nr_events < max_nr)) {
>
> That checking is done io aio_iopoll_getevents(), there are other
> conditions where we don't want to spin, like nr_events >= min_nr for
> instance. But all that logic is in aio_iopoll_getevents(), from here we
Right. We'll break from the loop in this case.
> just know that we probably need to continue if nr_events == 0.
>
> I don't think there's an issue here, and no spinning when we don't need
> it.
>
