Memory Arenas and Concurrent Bitmaps

• arena.c: Arena creation, reservation, traversal, and destruction.
• arena-alloc.c: Allocation, freeing, commitment, and purging of arena slices.
• arena-page.c: Per-heap arena page bitmaps, and finding, abandoning, and reclaiming abandoned pages.
• arena-page-alloc.c: Page allocation (_mi_arenas_page_alloc): reuse an abandoned page or allocate and initialize a fresh one; and freeing pages.
• arena-heap.c: Visiting, collecting, and moving or destroying all pages of a heap.
• arena.h: Private arena declarations, traversal callbacks, and layout helpers.
• arena-page.h: Private declarations and helpers shared by the arena page modules (guard pages, arena page bitmaps).
• bitmap.c: Concurrent bitmap searches and range operations; these bitmaps are used to manage the slices in an arena.
• bitmap-chunk.c: Bitmaps consist of 512-bit chunks; this provides the low-level atomic bit-field and bitmap-chunk operations.
• bitmap.h: Bitmap types, constants, and operation declarations.
• bitmap-chunk.h: Private declarations and iteration helpers for bitmap fields and chunks.