John Lask wrote:
on the other hand a function to release pool memory to the OS down to the current active level should (I hope) be easily implementable, and quickly incorporated into application where required, whereas arriving at one or more automatic deallocation policies would most likely require some analysis/trial and error.
I would suggest that trying to do this "automatically" in a way that is optimal for all applications requires some fairly serious heuristics. OTOH, for many Haskell programs it isn't a problem in the first place. (E.g., if you write something like Darcs which only ever runs for a few seconds, you barely need GC in the first place.) I'm just thinking, the application writer probably knows more about their specific program than the compiler designers do, so it would be nice to be able to provide hints to the RTS. (Still, until somebody implements it, I don't know how hard it is to actually decide when to use such a feature...)