I am curious, is it possible to implement a headerless allocator? Basically keep an index of free blocks and an index of used blocks using a B-tree or a skip li

I am curious, is it possible to implement a headerless allocator? Basically keep an index of free blocks and an index of used blocks using a B-tree or a skip list, and allocate and free them by simply moving from one index to the other. Presumably this would make it more cache friendly. Toying with allocators is one of my favorite programming pastimes for some reason.