Process-Level Memory Authority#3
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Introduce MemoryCore skeleton, implementation details remain incomplete and will be implemented in a follow-up.
Resources being studied for the implementation of a process-wide fixed-size memory block pool.
Added skeletons for process-wide MemoryPoolConfig and ProcessMemoryPool. Both are incomplete stubs; Update src/process/CMakeLists.txt to include the new source files
Prematurely adding necessary header dependency
Appended a comment block to dev_exe.cpp about potential debug-mode bad-address/sentinel values (several hex patterns and their decimal equivalents)
Annotate MemoryPoolConfig structure with CHEVRON_API to ensure proper symbol visibility from the shared library/object; Implementation remains incomplete
Added skeleton for strongly-typed DigitalSize template as a stub; Still incomplete
Moved digital size measurement facilities to 'include/chevron/common/units/digital' subdirectory; Implementation STILL INCOMPLETE
Add include/chevron/common/units/digital/unit_cast.hpp which introduces DigitalSizeCast, a constexpr template utility to convert between digital size unit types
Incomplete
Introduce a general units include header that centralizes unit-measure facilities; This front-facing header is still INCOMPLETE
Temporary 'size_t' references to be replaced with explicit unit types; Incomplete
Compile-time and runtime math utilities
Incomplete
Introduces an alignment and bit inspection header; Both headers incomplete
Adjustments to documentation comments
Introduce arithmetic and compound operators for DigitalSize; Moved class type traits above class definition
Replace raw size_t fields with unit-safe Bytes for block_size, chunk_size, and budget_ceiling in MemoryPoolConfig; Other fields and structure remain unchanged
Rolling example of application implementation with Chevron
Incomplete documentation
Added validation method stubs for process memory pool configuration; Incomplete implementation
Introduced memory description interface for types that are centered around describing a region in memory
Adjusted to inherit majority of public API from base memory description class
Introduced MemoryRegion class; inherits from memory description interface
Replace inconsistent comment "// TODO: INCOMPLETE DOC STRING!!!" with "TODO: INCOMPLETE DOCUMENTATION!!!"
The chunk descriptor type needs a default constructor to allocate instances in an array
Start of constructor and destructor for the process memory allocator; INCOMPLETE!!!
Removed invalid noexcept qualifier on method signature in header
- Catch polymorphic exception by reference rather than value - Adjusted comment banners
- Implementation in place - Still missing documentation comments
- Wrap possible failure point with try-catch statement - Misc. comment adjustments
Added new thread synchronization primitive to threading utilities. Tagged pointers require 16-byte atomics to account for a standard pointer and monotonically increasing swap counter INCOMPLETE DOCUMENTATION!!!
Introduced ScopeGuard which is a RAII guard that runs a provided lambda on scope exit for safe cleanup
Introduced general memory header that defines basic memory allocator types including FreeRegionNode and AtomicFreeListHead (an atomic TaggedPointer<void>) INCOMPLETE DOCUMENTATION!!!
- Included ScopeGuard and applied RAII to make allocation/error paths exception-safe - Removed manual try/catch blocks and simplified node construction; dismiss guards after successful publish. Improves safety and clarity without changing allocation semantics
Introduce ProcessMemoryPool declaration and core implementation. Header additions: new includes, ThreadLocalMemoryCache stub, FreeListHead alias, public ctor/dtor and inspection APIs, private members (free list head, bytes_acquired, blocks_per_chunk, config, allocator) and helper declarations. Source additions: constructor/destructor, block/chunk geometry computation, budget validation, allocator reinitialization, carve_and_link, push_batch/pop_batch implementing ABA-safe tagged-pointer CAS loops, and expand_memory with a budget gate, allocator acquisition and chunk integration (uses ScopeGuard/TaggedPointer). Many docs remain TODO and thread-local cache logic is left on-hold; this is a partial but functional core for lock-free block distribution.
Incomplete class declaration stub
Add alignas(16) to the TaggedPointer struct to guarantee 16-byte alignment. This ensures the type is properly aligned for double-width atomic operations
Introduce thread-local allocation/deallocation APIs and a CAS-based expansion gate to reduce contention and serialize OS memory growth. Changes: - Added ProcessMemoryPool::allocate() and deallocate() with a fast path using ThreadLocalMemoryCache and slow/refill paths that use pop_batch()/expand_memory(). - Extended ThreadLocalMemoryCache with free_blocks, adjusted semantics of cached_blocks, added has_memory_free(), and made drain_cache() non-const. - Implemented get_current_thread_cache() as a thread_local cache in the .cpp and updated its noexcept signature. - Added ExpandState (atomic ExpansionState) and expansion_state_ member; expand_memory() now uses CAS to ensure only one thread performs OS allocation, yielding other threads until expansion completes and restoring state with a scope guard. - Reordered and renamed some private helpers (carve_and_link, push_batch, pop_batch) and commented-out a platform lock-free static_assert. - Added #include <thread> in the implementation for yielding.
Introduce thread_mem_cache.cpp which adds the ThreadLocalMemoryCache methods for ProcessMemoryPool. - Implements destructor (drains cache), has_memory_free(), and drain_cache() that links the local free list into the shared pool via push_batch. - compute_growth_batch() and compute_shrink_batch() are added as INCOMPLETE placeholders
- Introduce TaggedPointer type to conditionally define FreeListHead to support MSVC's lack of a lock-free 128-bit std::atomic. - Add CHEVRON_MSVC code paths that use _InterlockedCompareExchange128 for loading and CAS on the free-list, while keeping std::atomic<TaggedPointer> for other platforms. - Include macro_defs.h and <intrin.h> (MSVC) and adjust push/pop logic accordingly. - Also clear block->next after allocation to avoid dangling links.
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Introduction of process-wide memory management components