Why general-purpose malloc / new causes memory fragmentation in long-running services:

General allocators add metadata headers (8-16 bytes) to every allocation and search free lists, causing heap fragmentation over millions of allocations.

Arena (Bump) Allocator:

• Pre-allocates a contiguous 10MB memory block.
• Allocating is a simple pointer increment (pCurrent += size). Sub-nanosecond execution time!
• Freeing everything resets the pointer back to start in 1 CPU cycle (pCurrent = pBase).

Arena allocators are standard in web servers and game engines for per-frame or per-request scratch memory.

Zero fragmentation, zero free-list traversal, and 100% cache locality.