All non-toy languages and compilers only add constant overhead; unfortunately that's still a problem, the goal is to not have any overhead at all. malloc/free

All non-toy languages and compilers only add constant overhead; unfortunately that's still a problem, the goal is to not have any overhead at all. malloc/free is fast with a moving GC, but moving is not, and if an object is never moved it's likely that it should not have been allocated on the heap in the first place. The cmpxchg problem is solvable by epoch-based reclamation libraries (RCU, crossbeam-epoch, etc.), and while a traditional GC also solves it, it's not necessary.