Region-based memory management

In computer science, region-based memory management is a type of memory management in which each allocated object is assigned to a region. A region, also called a partition, subpool, zone, arena, area, or memory context, is a collection of allocated objects that can be efficiently reallocated or deallocated all at once. Memory allocators using region-based managements are often called area allocators, and when they work by only "bumping" a single pointer, as bump allocators.

Like stack allocation, regions facilitate allocation and deallocation of memory with low overhead; but they are more flexible, allowing objects to live longer than the stack frame in which they were allocated. In typical implementations, all objects in a region are allocated in a single contiguous range of memory addresses, similarly to how stack frames are typically allocated.

In OS/360 and successors, the concept applies at two levels; each job runs within a contiguous partition^[a] or region.^[b] Storage allocation requests specify a subpool, and the application can free an entire subpool. Storage for a subpool is allocated from the region or partition in blocks that are a multiple of 2 Kib^[c] or 4 KiB^[d] that generally are not contiguous.
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