cba6f785a1
Add SuperSlab Prefault Box with 4MB MAP_POPULATE bug fix
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New Feature: ss_prefault_box.h
- Box for controlling SuperSlab page prefaulting policy
- ENV: HAKMEM_SS_PREFAULT (0=OFF, 1=POPULATE, 2=TOUCH)
- Default: OFF (safe mode until further optimization)
Bug Fix: 4MB MAP_POPULATE regression
- Problem: Fallback path allocated 4MB (2x size for alignment) with MAP_POPULATE
causing 52x slower mmap (0.585ms → 30.6ms) and 35% throughput regression
- Solution: Remove MAP_POPULATE from 4MB allocation, apply madvise(MADV_WILLNEED)
only to the aligned 2MB region after trimming prefix/suffix
Changes:
- core/box/ss_prefault_box.h: New prefault policy box (header-only)
- core/box/ss_allocation_box.c: Integrate prefault box, call ss_prefault_region()
- core/superslab_cache.c: Fix fallback path - no MAP_POPULATE on 4MB,
always munmap prefix/suffix, use MADV_WILLNEED for 2MB only
- docs/specs/ENV_VARS*.md: Document HAKMEM_SS_PREFAULT
Performance:
- bench_random_mixed: 4.32M ops/s (regression fixed, slight improvement)
- bench_tiny_hot: 157M ops/s with prefault=1 (no crash)
Box Theory:
- OS layer (ss_os_acquire): "how to mmap"
- Prefault Box: "when to page-in"
- Allocation Box: "when to call prefault"
🤖 Generated with Claude Code
Co-Authored-By: Claude <noreply@anthropic.com >
2025-12-04 20:11:24 +09:00
25cb7164c7
Comprehensive legacy cleanup and architecture consolidation
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Summary of Changes:
MOVED TO ARCHIVE:
- core/hakmem_tiny_legacy_slow_box.inc → archive/
* Slow path legacy code preserved for reference
* Superseded by Gatekeeper Box architecture
- core/superslab_allocate.c → archive/superslab_allocate_legacy.c
* Legacy SuperSlab allocation implementation
* Functionality integrated into new Box system
- core/superslab_head.c → archive/superslab_head_legacy.c
* Legacy slab head management
* Refactored through Box architecture
REMOVED DEAD CODE:
- Eliminated unused allocation policy variants from ss_allocation_box.c
* Reduced from 127+ lines of conditional logic to focused implementation
* Removed: old policy branches, unused allocation strategies
* Kept: current Box-based allocation path
ADDED NEW INFRASTRUCTURE:
- core/superslab_head_stub.c (41 lines)
* Minimal stub for backward compatibility
* Delegates to new architecture
- Enhanced core/superslab_cache.c (75 lines added)
* Added missing API functions for cache management
* Proper interface for SuperSlab cache integration
REFACTORED CORE SYSTEMS:
- core/hakmem_super_registry.c
* Moved registration logic from scattered locations
* Centralized SuperSlab registry management
- core/hakmem_tiny.c
* Removed 27 lines of redundant initialization
* Simplified through Box architecture
- core/hakmem_tiny_alloc.inc
* Streamlined allocation path to use Gatekeeper
* Removed legacy decision logic
- core/box/ss_allocation_box.c/h
* Dramatically simplified allocation policy
* Removed conditional branches for unused strategies
* Focused on current Box-based approach
BUILD SYSTEM:
- Updated Makefile for archive structure
- Removed obsolete object file references
- Maintained build compatibility
SAFETY & TESTING:
- All deletions verified: no broken references
- Build verification: RELEASE=0 and RELEASE=1 pass
- Smoke tests: 100% pass rate
- Functional verification: allocation/free intact
Architecture Consolidation:
Before: Multiple overlapping allocation paths with legacy code branches
After: Single unified path through Gatekeeper Boxes with clear architecture
Benefits:
- Reduced code size and complexity
- Improved maintainability
- Single source of truth for allocation logic
- Better diagnostic/observability hooks
- Foundation for future optimizations
🤖 Generated with [Claude Code](https://claude.com/claude-code )
Co-Authored-By: Claude <noreply@anthropic.com >
2025-12-04 14:22:48 +09:00
6ac6f5ae1b
Refactor: Split hakmem_tiny_superslab.c + unified backend exit point
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Major refactoring to improve maintainability and debugging:
1. Split hakmem_tiny_superslab.c (1521 lines) into 7 focused files:
- superslab_allocate.c: SuperSlab allocation/deallocation
- superslab_backend.c: Backend allocation paths (legacy, shared)
- superslab_ace.c: ACE (Adaptive Cache Engine) logic
- superslab_slab.c: Slab initialization and bitmap management
- superslab_cache.c: LRU cache and prewarm cache management
- superslab_head.c: SuperSlabHead management and expansion
- superslab_stats.c: Statistics tracking and debugging
2. Created hakmem_tiny_superslab_internal.h for shared declarations
3. Added superslab_return_block() as single exit point for header writing:
- All backend allocations now go through this helper
- Prevents bugs where headers are forgotten in some paths
- Makes future debugging easier
4. Updated Makefile for new file structure
5. Added header writing to ss_legacy_backend_box.c and
ss_unified_backend_box.c (though not currently linked)
Note: Header corruption bug in Larson benchmark still exists.
Class 1-6 allocations go through TLS refill/carve paths, not backend.
Further investigation needed.
🤖 Generated with [Claude Code](https://claude.com/claude-code )
Co-Authored-By: Claude <noreply@anthropic.com >
2025-11-29 05:13:04 +09:00
