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Heap Space ↔ V8 organize Heap into Page regions to work with Garbage Collector

aka Space, Spaces

Memory Page​

Virtual Memory Block, fixed-length contigious, ref by Page Table

New-space​

Small Heap Space to contain most objects, independent of other Spaces, for fast Garbage-Collection

Old-pointer-space​

Space to contain most objects with Pointers to other objects, moved here from New-space

Old-data-space​

Space to contain objects with raw data (no Pointers). Strings, boxed numbers, and arrays of unboxed doubles move here from New-space for a while.

Large-object-space​

Space to contain large objects above size limits of other Spaces. Each object assign mmap'd region of memory. Large objects never moved by Garbage Collector.

Code-space​

Space to contain JIT Compiled Code objects for executable memory (may also allocate inside Executable JIT Code in Large-object-space)

Cell-space, property-cell-space and map-space​

Spaces to contain Cells, PropertyCells, and Maps, respectively. Each Space contains same sized objects with some constraints on type of objects to point to, to simplify Garbage-Collection.

References​

  1. New-space ↔ Small Heap Space to contain most objects, independent of other Spaces, for fast Garbage-Collection

  2. Old-pointer-space ↔ Space to contain most objects with Pointers to other objects, moved here from New-space

  3. Old-data-space ↔ Space to contain objects with raw data (no Pointers). Strings, boxed numbers, and arrays of unboxed doubles move here from New-space for a while.

  4. Large-object-space ↔ Space to contain large objects above size limits of other Spaces. Each object assign mmap'd region of memory. Large objects never moved by Garbage Collector.

  5. Code-space ↔ Space to contain JIT Compiled Code objects for executable memory (may also allocate inside Executable JIT Code in Large-object-space)

  6. Cell-space, property-cell-space and map-space ↔ Spaces to contain Cells, PropertyCells, and Maps, respectively. Each Space contains same sized objects with some constraints on type of objects to point to, to simplify Garbage-Collection.