Re: nanosecond debiting cv_timedwait

[Christoph Badura <bad%bsd.de@localhost>]

On Fri, Mar 20, 2015 at 01:37:59PM +0000, Taylor R Campbell wrote:
> int	cv_timedwaitns(kcondvar_t *, kmutex_t *, struct timespec *);
> int	cv_timedwaitns_sig(kcondvar_t *, kmutex_t *, struct timespec *);

To me the small difference in the name doesn't adequately reflect the
semantic difference.  A different name that makes the semantic difference
more obvious would be preferable.

We don't want people to think a mechanical conversion to:

	struct timespec timeout = { .tv_sec = 1, .tv_nsec = 0 };
	struct timespec now, end;
	int error;

	nanotime(&now);
	timespecadd(&now, &timeout, &end);
	while (!condition) {
		error = cv_timedwait_sig(&sc->sc_cv, &sc->sc_lock,
		    &timeout);
		if (error)
			goto fail;
		nanotime(&now);
		if (timespeccmp(&end, &now, <) {
			error = EWOULDBLOCK;
			goto fail;
		}
		timespecsub(&end, &now, &timeout);
	}

is going to work as before. Or does it?

But maybe that isn't mechanical enough.

--chris