allocatore

Allocatore, in computing, is a software component responsible for allocating and deallocating dynamic resources, most commonly memory. It abstracts the process of obtaining space from the system or runtime and returning it when no longer needed. A typical allocator maintains metadata about allocated blocks, supports alignment requirements, and may implement pooling, defragmentation, and thread-safety.

In languages like C and C++, malloc and free are part of the runtime's allocator, and language features such as C++'s allocator concept allow custom allocators to be supplied for containers. Allocators may use strategies such as first-fit, best-fit, or more sophisticated methods (slab, buddy, or pool allocators) to balance speed and memory utilization. Fragmentation, allocation overhead, and locality of reference are important design considerations.

Allocators can be general-purpose or specialized for particular workloads or memory pools. Some systems expose fixed-size memory pools to reduce fragmentation and improve predictability, which is important in real-time contexts. In higher-level runtimes, memory allocation is often mixed with garbage collection or region-based management, and the term allocator may refer to the component responsible for obtaining memory until collection, as in managed languages like Java or .NET, where allocation is followed by later reclamation.

In Rust, the global allocator can be replaced with a custom one; in operating systems, the kernel provides low-level allocators that service user-space requests after page allocation. The concept is central to performance, memory footprint, and determinism.