hakmem/core/hakmem_bigcache.h

// hakmem_bigcache.h - Big-Block Cache (Box理論)
// Purpose: Per-site ring cache for large allocations (>= 1MB)
//
// License: MIT
// Date: 2025-10-21
// Phase 2c: Dynamic hash table implementation

#pragma once
#include <stddef.h>
#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

// ============================================================================
// BigCache Box - サイト別大規模ブロックキャッシュ
// ============================================================================

// Phase 2c: Dynamic hash table configuration
#define BIGCACHE_INITIAL_CAPACITY 256   // Initial bucket count (power of 2)
#define BIGCACHE_MAX_CAPACITY 65536     // Max 64K buckets (power of 2)
#define BIGCACHE_LOAD_FACTOR 0.75f      // Resize at 75% load
#define BIGCACHE_MIN_SIZE 524288        // 512KB minimum for caching

// Phase 6.11: Expanded size classes (4 → 8 classes, finer granularity to reduce internal fragmentation)
#define BIGCACHE_NUM_CLASSES 8         // Number of size classes (Phase 6.11: increased from 4)
#define BIGCACHE_CLASS_512KB  524288   // 512KB size class (NEW)
#define BIGCACHE_CLASS_1MB   1048576   // 1MB size class
#define BIGCACHE_CLASS_2MB   2097152   // 2MB size class
#define BIGCACHE_CLASS_3MB   3145728   // 3MB size class (NEW: reduces fragmentation)
#define BIGCACHE_CLASS_4MB   4194304   // 4MB size class
#define BIGCACHE_CLASS_6MB   6291456   // 6MB size class (NEW)
#define BIGCACHE_CLASS_8MB   8388608   // 8MB size class
#define BIGCACHE_CLASS_16MB 16777216   // 16MB size class (NEW)

// BigCache API (Box Interface)

// Try to get cached block for this site
// Returns: 1 if hit (out_ptr set), 0 if miss
int hak_bigcache_try_get(size_t size, uintptr_t site, void** out_ptr);

// Try to put freed block into cache
// Returns: 1 if cached, 0 if rejected (full/not cacheable)
int hak_bigcache_put(void* ptr, size_t class_bytes, uintptr_t site);

// Initialize BigCache (called from hak_init)
void hak_bigcache_init(void);

// Cleanup BigCache (called from hak_shutdown)
void hak_bigcache_shutdown(void);

// Stats (for debugging)
void hak_bigcache_print_stats(void);

// Set free callback (for proper cleanup on eviction)
typedef void (*hak_bigcache_free_fn_t)(void* ptr, size_t size);
void hak_bigcache_set_free_callback(hak_bigcache_free_fn_t fn);

#ifdef __cplusplus
}
#endif