On Mon, 2015-08-10 at 09:16 -0700, Matt Turner wrote: > On Fri, Aug 7, 2015 at 10:09 AM, Ian Romanick <i...@freedesktop.org> wrote: > > I know we've talked about this about 100 times, but something in the > > back of my mind tells me that we have a pre-existing race. What happens > > if the p_atomic_dec_zero happens on thread A while thread B is between > > the _mesa_lookup_renderbuffer call and the _mesa_reference_renderbuffer > > call on the same object? Won't thread A free the memory out from under > > thread B? > > Generally: > > RefCount is initialized to 1 (in all cases but renderbuffers... that > might be a bug -- did you choose renderbuffers in your example for > this reason?). When Bind is called the first time, RefCount is > incremented to 2. > > When Delete is called, RefCount is decremented -- RefCount only goes > to 0 only if the object isn't bound anywhere, in which case it's > actually deleted. If The object is still bound somewhere and RefCount > is decremented to non-zero, the object cannot be rebound and will be > deleted when its last reference is unbound. > > Commit 42aaa548 changed the renderbuffer code from RefCount = 1 to = > 0. It seems pretty clearly wrong to me, since a > glGenRenderbuffers()/glDeleteRenderBuffers() pair would fail to > actually delete the renderbuffers. Does anyone else read it > differently?
Looking over this again what your saying looks correct. I had convinced myself otherwise. I doubt it will register anything on your benchmark but I also noticed the wrapper around the _mesa_reference_sampler_object call isn't required at least for samplerobj it may also be the case elsewhere I haven't checked yet. http://lists.freedesktop.org/archives/mesa-dev/2015-August/091171.html > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/mesa-dev _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
