[lttng-dev] [PATCH 2/2] Use _umtx_op for futex on FreeBSD

[Alex Xu]

Quoting Mathieu Desnoyers (2020-01-27 18:48:24)
> Please move the futex_noasync definition after futex_async, considering that
> futex_noasync uses futex_async().

Oops. Fixed that when testing but didn't copy it back to my local copy.

> Also, do you have a link to the API documentation of _umtx_op() ?
> I would like to double-check that all its return values are
> expected by the callers.

https://www.freebsd.org/cgi/man.cgi?query=_umtx_op

I took a look at the man page, the only "interesting" one is EINTR, but
that's the same as Linux.

https://gitlab.freedesktop.org/mesa/mesa/blob/master/src/util/futex.h
doesn't adjust the errno, but it does fiddle with the timeout. I will
add that in the next version.