Reference counted containers prototype

[Andrei Alexandrescu]

On 12/26/11 12:46 PM, Michel Fortin wrote:
> Although I am a little concerned by this
> small but important implementation detail:
>
> Your RefCounted destructor is racy.
>
> Just like other reference counted things in Phobos, if you somehow store
> a reference on the GC heap (as a class member for instance), the
> destructor for that reference struct is called from the GC thread and
> will decrement the counter from that thread, while another reference
> could play with the counter from another thread. I know you have plans
> for a general fix for that hole in destructors, but meanwhile it'd be
> wise to change the counter to a shared uint and use atomic operations to
> avoid low level races.

Does the current implementation unfreezes all threads before calling the 
destructors? If so, indeed there's a race.

BTW, the plan is to have the same thread that constructed objects to 
call their destructors; each thread would have a worklist of garbage 
objects to destroy. The list can be reduced during calls to allocation 
functions within each thread, and of course when the thread terminates.


Andrei