hakmem/core/box/pool_config_box.h

// pool_config_box.h — Box: Pool Configuration & ENV Gates
//
// Purpose: Centralized ENV gate predicates for pool allocator
// Pattern: Lazy static int cache (matches tiny_heap_env_box.h style)
// All functions are static inline (zero-cost abstraction)

#ifndef POOL_CONFIG_BOX_H
#define POOL_CONFIG_BOX_H

#include "tiny_heap_env_box.h"  // TinyHeap profile (C7_SAFE modes)
#include "../hakmem_build_flags.h"
#include <stdlib.h>
#include <string.h>

// ============================================================================
// Pool v2 Configuration
// ============================================================================

// Pool v2 is experimental. Default OFF (use legacy v1 path).
static inline int hak_pool_v2_enabled(void) {
#if HAKMEM_FAST_PROFILE_PRUNE_BACKENDS
    // Phase 64: Backend pruning - disable POOL_V2 in Mixed workload
    // Compile-time constant for DCE (unreachable code elimination)
    return 0;
#else
    static int g = -1;
    if (__builtin_expect(g == -1, 0)) {
        const char* e = getenv("HAKMEM_POOL_V2_ENABLED");
        g = (e && *e && *e != '0') ? 1 : 0;
    }
    return g;
#endif
}

// Fine-grained switches (only used when v2 is enabled).
static inline int hak_pool_v2_block_to_user_enabled(void) {
    static int g = -1;
    if (__builtin_expect(g == -1, 0)) {
        const char* e = getenv("HAKMEM_POOL_V2_BLOCK_TO_USER");
        g = (e && *e && *e != '0') ? 1 : 0;
        if (g == -1) g = 1;
    }
    return g;
}

static inline int hak_pool_v2_tls_fast_enabled(void) {
    static int g = -1;
    if (__builtin_expect(g == -1, 0)) {
        const char* e = getenv("HAKMEM_POOL_V2_TLS_FAST_PATH");
        g = (e && *e && *e != '0') ? 1 : 0;
        if (g == -1) g = 1;
    }
    return g;
}

// ============================================================================
// Pool v1 Configuration
// ============================================================================

// Pool v1 flatten (hot path only) is experimental and opt-in.
static inline int hak_pool_v1_flatten_enabled(void) {
    static int g = -1;
    if (__builtin_expect(g == -1, 0)) {
        // C7_SAFE/C7_ULTRA_BENCH プロファイルでは、安全側で強制 OFF
        int mode = tiny_heap_profile_mode();
        if (mode == TINY_HEAP_PROFILE_C7_SAFE || mode == TINY_HEAP_PROFILE_C7_ULTRA_BENCH) {
            g = 0;
            return g;
        }
        const char* e = getenv("HAKMEM_POOL_V1_FLATTEN_ENABLED");
        g = (e && *e && *e != '0') ? 1 : 0;
    }
    return g;
}

// Phase POOL-FREE-V1-OPT Step 2: Fast/Slow split for v1 free
// When enabled, same-thread TLS free skips mid_desc_lookup (1回→0回)
// Requires g_hdr_light_enabled == 0 for header-based owner_tid
// Default OFF for safety
static inline int hak_pool_v1_free_fastsplit_enabled(void) {
    static int g = -1;
    if (__builtin_expect(g == -1, 0)) {
        const char* e = getenv("HAKMEM_POOL_V1_FREE_FASTSPLIT");
        g = (e && *e == '1') ? 1 : 0;  // default OFF
    }
    return g;
}

// ============================================================================
// Statistics & Monitoring Configuration
// ============================================================================

static inline int hak_pool_v1_flatten_stats_enabled(void) {
    static int g = -1;
    if (__builtin_expect(g == -1, 0)) {
        const char* e = getenv("HAKMEM_POOL_V1_FLATTEN_STATS");
        g = (e && *e && *e != '0') ? 1 : 0;
    }
    return g;
}

// Phase POOL-FREE-V1-OPT Step 1: Reject reason stats
// Tracks why hak_pool_free_fast_v2_impl rejected (fell through to v1)
static inline int hak_pool_free_v1_reject_stats_enabled(void) {
    static int g = -1;
    if (__builtin_expect(g == -1, 0)) {
        const char* e = getenv("HAKMEM_POOL_FREE_V1_REJECT_STATS");
        g = (e && *e == '1') ? 1 : 0;  // default OFF
    }
    return g;
}

// ============================================================================
// Caching Configuration
// ============================================================================

// Mid desc lookup TLS cache (mid bench opt-in; default OFF)
static inline int hak_mid_desc_cache_enabled(void) {
    static int g = -1;
    if (__builtin_expect(g == -1, 0)) {
        const char* e = getenv("HAKMEM_MID_DESC_CACHE_ENABLED");
        g = (e && *e && *e != '0') ? 1 : 0;
    }
    return g;
}

#endif  // POOL_CONFIG_BOX_H