*braces oneself*
Just a quick dumb question here, in order not to pollute the GitHub issue:
"Specifically, this allocator will maintain an intrusive doubly linked list of currently allocated heap blocks, and will provide an API to iterate the blocks."
From the little that I know, allocators typically keep an indexing structure for free block-bookkeeping. I understand that your suggestion is to extend this feature to allocated blocks too. A naive and rough heuristic would say that such an extension would double the allocator's response latency compared to a standard mechanism (if "meta" header fields were picked smart enough, memory could be kept about the same).
I can see why live heap feedback would be sweet to have, but is the performance trade-off acceptable? (that is, if I'm not missing something in the first place)