[hackathon] FreeTree is FreeList on autotune

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On Saturday, 2 May 2015 at 06:28:01 UTC, Andrei Alexandrescu 
wrote:
> I'm just done implementing a pretty cool allocator: FreeTree.
>
> https://github.com/andralex/phobos/blob/allocator/std/experimental/allocator/free_tree.d
>
> http://erdani.com/d/phobos-prerelease/std_experimental_allocator_free_tree.html
>
> It's similar to the classic free list allocator but instead of 
> a singly-linked list it uses a binary search tree for 
> accommodating blocks of arbitrary size. The binary search tree 
> accommodates duplicates by storing one extra pointer for each 
> node, effectively embedding a singly-linked list (a free list 
> really) for each node.
>
> So a FreeTree is have a bunch of freelists organized in a 
> binary search tree. The tree is not balanced; instead, it uses 
> an LRU heuristic - each freed block is inserted as (or close 
> to) the root. Over the lifetime of a free tree, free lists 
> naturally appear and disappear as dictated by the sizes most 
> frequently allocated by the application.
>
> Feedback is welcome!
>
>
> Andrei

 From the doc:

>If ParentAllocator defines (deallocate|allocate), ...

I forget what the rules are for allocators exactly, but isn't 
something only an allocator if it defines allocate, deallocate, 
owns, etc.? It just seems weird that you mentioned something that 
I thought was implicit.