I’ve always understood an arena to use a bump pointer for allocation and to support only a global deallocation, as the GP describes. A pool or slab allocator s

I’ve always understood an arena to use a bump pointer for allocation and to support only a global deallocation, as the GP describes. A pool or slab allocator separates allocations into one of a range of fixed-size chunks to avoid fragmentation. Such allocators do support object-by-object deallocation.