[vlc-devel] [PATCH 2/4] libvlc: media_player: use vlc_atomic_rc for refcount

[Alexandre Janniaux]

On Mon, Nov 23, 2020 at 11:13:04AM +0100, Romain Vimont wrote:
> On Mon, Nov 23, 2020 at 11:13:55AM +0200, Rémi Denis-Courmont wrote:
> > Hi,
> >
> > I don't really the point in using an atomic variable if it can't avoid the
> > mutex.
>
> But the mutex locking is avoided for refcounting (and this mutex is for
> other things).

In addition to the fact it's actually removing mutex in some calls,
it's also removing a lot of confusing locking code, including potential
future maintenance errors because of missing unlock on the non-release
path. Atomic are also not subject to lock inversion issues or such, and
even in the simplest case of my patch, it is at most replacing one
variable by another one, so not really adding complexity here.

Moreover, having a common base for refcounting in every libvlc object
helps readability a lot.

Regards,
--
Alexandre Janniaux
Videolabs