hakmem/core/box/hak_alloc_api.inc.h

// hak_alloc_api.inc.h — Box: hak_alloc_at() implementation
#ifndef HAK_ALLOC_API_INC_H
#define HAK_ALLOC_API_INC_H

__attribute__((always_inline))
inline void* hak_alloc_at(size_t size, hak_callsite_t site) {
#if HAKMEM_DEBUG_TIMING
    HKM_TIME_START(t0);
#endif
    if (!g_initialized) hak_init();

    uintptr_t site_id = (uintptr_t)site;

    if (__builtin_expect(size <= TINY_MAX_SIZE, 1)) {
#if HAKMEM_DEBUG_TIMING
        HKM_TIME_START(t_tiny);
#endif
        void* tiny_ptr = NULL;
#ifdef HAKMEM_TINY_PHASE6_BOX_REFACTOR
        tiny_ptr = hak_tiny_alloc_fast_wrapper(size);
#elif defined(HAKMEM_TINY_PHASE6_ULTRA_SIMPLE)
        tiny_ptr = hak_tiny_alloc_ultra_simple(size);
#elif defined(HAKMEM_TINY_PHASE6_METADATA)
        tiny_ptr = hak_tiny_alloc_metadata(size);
#else
        tiny_ptr = hak_tiny_alloc(size);
#endif
#if HAKMEM_DEBUG_TIMING
        HKM_TIME_END(HKM_CAT_TINY_ALLOC, t_tiny);
#endif
        if (tiny_ptr) { hkm_ace_track_alloc(); return tiny_ptr; }

        // PHASE 7 CRITICAL FIX: No malloc fallback for Tiny failures
        // If Tiny fails for size <= TINY_MAX_SIZE, let it flow to Mid/ACE layers
        // This prevents mixed HAKMEM/libc allocation bugs
#if HAKMEM_TINY_HEADER_CLASSIDX
        if (!tiny_ptr && size <= TINY_MAX_SIZE) {
            // Tiny failed - log and continue to Mid/ACE (no early return!)
            static int log_count = 0;
            if (log_count < 3) {
                fprintf(stderr, "[DEBUG] Phase 7: tiny_alloc(%zu) failed, trying Mid/ACE layers (no malloc fallback)\n", size);
                log_count++;
            }
            // Continue to Mid allocation below (do NOT fallback to malloc!)
        }
#else
        static int log_count = 0; if (log_count < 3) { fprintf(stderr, "[DEBUG] tiny_alloc(%zu) returned NULL, falling back\n", size); log_count++; }
#endif
    }

    hkm_size_hist_record(size);

    if (__builtin_expect(mid_is_in_range(size), 0)) {
#if HAKMEM_DEBUG_TIMING
        HKM_TIME_START(t_mid);
#endif
        void* mid_ptr = mid_mt_alloc(size);
#if HAKMEM_DEBUG_TIMING
        HKM_TIME_END(HKM_CAT_POOL_GET, t_mid);
#endif
        if (mid_ptr) return mid_ptr;
    }

#if HAKMEM_FEATURE_EVOLUTION
    if (g_evo_sample_mask > 0) {
        static _Atomic uint64_t tick_counter = 0;
        if ((atomic_fetch_add(&tick_counter, 1) & g_evo_sample_mask) == 0) {
            struct timespec now; clock_gettime(CLOCK_MONOTONIC, &now);
            uint64_t now_ns = now.tv_sec * 1000000000ULL + now.tv_nsec;
            if (hak_evo_tick(now_ns)) {
                int new_strategy = hak_elo_select_strategy();
                atomic_store(&g_cached_strategy_id, new_strategy);
            }
        }
    }
#endif

    size_t threshold;
    if (HAK_ENABLED_LEARNING(HAKMEM_FEATURE_ELO)) {
        int strategy_id = atomic_load(&g_cached_strategy_id);
        threshold = hak_elo_get_threshold(strategy_id);
    } else {
        threshold = 2097152;
    }

    if (HAK_ENABLED_CACHE(HAKMEM_FEATURE_BIGCACHE) && size >= threshold) {
        void* cached_ptr = NULL;
#if HAKMEM_DEBUG_TIMING
        HKM_TIME_START(t_bc);
#endif
        if (hak_bigcache_try_get(size, site_id, &cached_ptr)) {
#if HAKMEM_DEBUG_TIMING
            HKM_TIME_END(HKM_CAT_BIGCACHE_GET, t_bc);
#endif
            return cached_ptr;
        }
#if HAKMEM_DEBUG_TIMING
        HKM_TIME_END(HKM_CAT_BIGCACHE_GET, t_bc);
#endif
    }

    if (size > TINY_MAX_SIZE && size < threshold) {
        const FrozenPolicy* pol = hkm_policy_get();
#if HAKMEM_DEBUG_TIMING
        HKM_TIME_START(t_ace);
#endif
        void* l1 = hkm_ace_alloc(size, site_id, pol);
#if HAKMEM_DEBUG_TIMING
        HKM_TIME_END(HKM_CAT_POOL_GET, t_ace);
#endif
        if (l1) return l1;
    }

    // PHASE 7 CRITICAL FIX: Handle allocation gap (1KB-8KB) when ACE is disabled
    // Size range:
    //   0-1024:      Tiny allocator
    //   1025-8191:   Gap! (Mid starts at 8KB, ACE often disabled)
    //   8KB-32KB:    Mid allocator
    //   32KB-2MB:    ACE (if enabled, otherwise mmap)
    //   2MB+:        mmap
    //
    // Solution: Use mmap for gap when ACE failed (ACE disabled or OOM)

    void* ptr;
    if (size >= threshold) {
        // Large allocation (>= 2MB default): use mmap
#if HAKMEM_DEBUG_TIMING
        HKM_TIME_START(t_mmap);
#endif
        ptr = hak_alloc_mmap_impl(size);
#if HAKMEM_DEBUG_TIMING
        HKM_TIME_END(HKM_CAT_SYSCALL_MMAP, t_mmap);
#endif
    } else if (size >= TINY_MAX_SIZE) {
        // Mid-range allocation (1KB-2MB): try mmap as final fallback
        // This handles the gap when ACE is disabled or failed
        static _Atomic int gap_alloc_count = 0;
        int count = atomic_fetch_add(&gap_alloc_count, 1);
        if (count < 3) {
            fprintf(stderr, "[HAKMEM] INFO: Using mmap for mid-range size=%zu (ACE disabled or failed)\n", size);
        }
#if HAKMEM_DEBUG_TIMING
        HKM_TIME_START(t_mmap);
#endif
        ptr = hak_alloc_mmap_impl(size);
#if HAKMEM_DEBUG_TIMING
        HKM_TIME_END(HKM_CAT_SYSCALL_MMAP, t_mmap);
#endif
    } else {
        // Should never reach here (size <= TINY_MAX_SIZE should be handled by Tiny)
        static _Atomic int oom_count = 0;
        int count = atomic_fetch_add(&oom_count, 1);
        if (count < 10) {
            fprintf(stderr, "[HAKMEM] OOM: Unexpected allocation path for size=%zu, returning NULL\n", size);
            fprintf(stderr, "[HAKMEM]      (OOM count: %d) This should not happen!\n", count + 1);
        }
#if HAKMEM_DEBUG_TIMING
        HKM_TIME_START(t_malloc);
        HKM_TIME_END(HKM_CAT_FALLBACK_MALLOC, t_malloc);  // Keep timing for compatibility
#endif
        errno = ENOMEM;
        return NULL;
    }
    if (!ptr) return NULL;

    if (g_evo_sample_mask > 0) { hak_evo_record_size(size); }
    AllocHeader* hdr = (AllocHeader*)((char*)ptr - HEADER_SIZE);
    if (hdr->magic != HAKMEM_MAGIC) { fprintf(stderr, "[hakmem] ERROR: Invalid magic in allocated header!\n"); return ptr; }
    hdr->alloc_site = site_id;
    hdr->class_bytes = (size >= threshold) ? threshold : 0;

#if HAKMEM_DEBUG_TIMING
    HKM_TIME_END(HKM_CAT_HAK_ALLOC, t0);
#endif
    return ptr;
}

#endif // HAK_ALLOC_API_INC_H