4 commits

Author	SHA1	Message	Date
Andreas Kling	b6d4eea7ac	LibJS: Never give back virtual memory once it belongs to a cell type ... Instead of returning HeapBlock memory to the kernel (or a non-type specific shared cache), we now keep a BlockAllocator per CellAllocator and implement "deallocation" by basically informing the kernel that we don't need the physical memory right now. This is done with MADV_FREE or MADV_DONTNEED if available, but for other platforms (including SerenityOS) we munmap and then re-mmap the memory to achieve the same effect. It's definitely clunky, so I've added a FIXME about implementing the madvise options on SerenityOS too. The important outcome of this change is that GC types that use a type-specific allocator become immune to use-after-free type confusion attacks, since their virtual addresses will only ever be re-used for the same exact type again and again. Fixes #22274	2023-12-31 15:35:56 +01:00
Andreas Kling	11c968fa1f	LibJS: Make Heap aware of all CellAllocators ... Also add a link from HeapBlock to their owning CellAllocator. This fixes an issue where the Heap would skip over non-size-based cell allocators.	2023-12-23 23:02:10 +01:00
Brian Gianforcaro	e2d154c74d	LibJS: Use default instead of an empty constructor/destructor ... Default implementations allow for more optimizations. See: https://pvs-studio.com/en/docs/warnings/v832/	2021-09-16 17:17:13 +02:00
Andreas Kling	9b699bad94	LibJS: Rename Allocator => CellAllocator ... Now that we have a BlockAllocator as well, it seems appropriate to name the allocator-that-allocates-cells something more specific to match.	2021-05-27 19:56:12 +02:00

Renamed from Userland/Libraries/LibJS/Heap/Allocator.cpp (Browse further)