The AmigaOS4.0 memory architecture is based on the 'slab allocator' system or 'object cache'. In essence, the slab allocator only allocates objects of a single size, allocating these in larger batches (slabs) from the low-level page allocator. These slabs are then divided up into buffers of the required size, and kept within a list in the slab allocator.
More info here: http://www.hyperion-entertainment.com/