248 lines
10 KiB
C
248 lines
10 KiB
C
// malloc_tiny_fast.h - Phase 26: Front Gate Unification (Tiny Fast Path)
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//
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// Goal: Eliminate 3-layer overhead (malloc → hak_alloc_at → wrapper → tiny_alloc_fast)
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// Target: +10-15% performance (11.35M → 12.5-13.5M ops/s)
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//
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// Design (ChatGPT analysis):
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// - Replace: malloc → hak_alloc_at (236 lines) → wrapper (diagnostics) → tiny_alloc_fast
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// - With: malloc → malloc_tiny_fast (single-layer, direct to Unified Cache)
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// - Preserves: Safety checks (lock depth, initializing, LD_SAFE, jemalloc block)
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// - Leverages: Phase 23 Unified Cache (tcache-style, 2-3 cache misses)
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//
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// Performance:
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// - Current overhead: malloc(8.97%) + routing + wrapper(3.63%) + tiny(5.37%) = 17.97%
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// - BenchFast ceiling: 8-10 instructions (~1-2% overhead)
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// - Gap: ~16%
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// - Target: Close half the gap (+10-15% improvement)
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//
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// ENV Variables:
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// HAKMEM_FRONT_GATE_UNIFIED=1 # Enable Front Gate Unification (default: 0, OFF)
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#ifndef HAK_FRONT_MALLOC_TINY_FAST_H
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#define HAK_FRONT_MALLOC_TINY_FAST_H
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#include <stdint.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <pthread.h> // For pthread_self() in cross-thread check
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#include "../hakmem_build_flags.h"
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#include "../hakmem_tiny_config.h" // For TINY_NUM_CLASSES
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#include "../hakmem_super_registry.h" // For cross-thread owner check
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#include "../superslab/superslab_inline.h" // For ss_fast_lookup, slab_index_for (Phase 12)
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#include "../box/ss_slab_meta_box.h" // For ss_slab_meta_owner_tid_low_get
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#include "../box/free_remote_box.h" // For tiny_free_remote_box
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#include "tiny_unified_cache.h" // For unified_cache_pop_or_refill
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#include "../tiny_region_id.h" // For tiny_region_id_write_header
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#include "../hakmem_tiny.h" // For hak_tiny_size_to_class
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#include "../box/tiny_front_hot_box.h" // Phase 4-Step2: Hot Path Box
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#include "../box/tiny_front_cold_box.h" // Phase 4-Step2: Cold Path Box
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// Helper: current thread id (low 32 bits) for owner check
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#ifndef TINY_SELF_U32_LOCAL_DEFINED
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#define TINY_SELF_U32_LOCAL_DEFINED
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static inline uint32_t tiny_self_u32_local(void) {
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return (uint32_t)(uintptr_t)pthread_self();
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}
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#endif
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// ============================================================================
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// ENV Control (cached, lazy init)
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// ============================================================================
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// Enable flag (default: 0, OFF)
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static inline int front_gate_unified_enabled(void) {
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static int g_enable = -1;
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if (__builtin_expect(g_enable == -1, 0)) {
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const char* e = getenv("HAKMEM_FRONT_GATE_UNIFIED");
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g_enable = (e && *e && *e == '0') ? 0 : 1; // default ON
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#if !HAKMEM_BUILD_RELEASE
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if (g_enable) {
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fprintf(stderr, "[FrontGate-INIT] front_gate_unified_enabled() = %d\n", g_enable);
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fflush(stderr);
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}
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#endif
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}
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return g_enable;
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}
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// ============================================================================
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// Phase 4-Step2: malloc_tiny_fast() - Hot/Cold Path Box (ACTIVE)
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// ============================================================================
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// Ultra-thin Tiny allocation using Hot/Cold Path Box (Phase 4-Step2)
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//
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// IMPROVEMENTS over Phase 26-A:
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// - Branch reduction: Hot path has only 1 branch (cache empty check)
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// - Branch hints: TINY_HOT_LIKELY/UNLIKELY for better CPU prediction
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// - Hot/Cold separation: Keeps hot path small (better i-cache locality)
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// - Explicit fallback: Clear hot→cold transition
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//
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// PERFORMANCE:
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// - Baseline (Phase 26-A, no PGO): 53.3 M ops/s
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// - Hot/Cold Box (no PGO): 57.2 M ops/s (+7.3%)
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//
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// DESIGN:
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// 1. size → class_idx (same as Phase 26-A)
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// 2. Hot path: tiny_hot_alloc_fast() - cache hit (1 branch)
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// 3. Cold path: tiny_cold_refill_and_alloc() - cache miss (noinline, cold)
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//
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// Preconditions:
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// - Called AFTER malloc() safety checks (lock depth, initializing, LD_SAFE)
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// - size <= tiny_get_max_size() (caller verified)
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// Returns:
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// - USER pointer on success
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// - NULL on failure (caller falls back to normal path)
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//
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__attribute__((always_inline))
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static inline void* malloc_tiny_fast(size_t size) {
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// 1. size → class_idx (inline table lookup, 1-2 instructions)
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int class_idx = hak_tiny_size_to_class(size);
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// 2. Phase 4-Step2: Hot/Cold Path Box
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// Try hot path first (cache hit, 1 branch)
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void* ptr = tiny_hot_alloc_fast(class_idx);
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if (TINY_HOT_LIKELY(ptr != NULL)) {
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// Hot path: Cache hit → return USER pointer
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return ptr;
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}
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// 3. Cold path: Cache miss → refill + alloc
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// noinline, cold attribute keeps this code out of hot path
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return tiny_cold_refill_and_alloc(class_idx);
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}
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// ============================================================================
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// Phase 26-B: free_tiny_fast() - Ultra-thin Tiny deallocation
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// ============================================================================
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// Single-layer Tiny deallocation (bypasses hak_free_at + wrapper + diagnostics)
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// Preconditions:
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// - ptr is from malloc_tiny_fast() (has valid header)
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// - Front Gate Unified is enabled
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// Returns:
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// - 1 on success (pushed to Unified Cache)
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// - 0 on failure (caller falls back to normal free path)
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__attribute__((always_inline))
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static inline int free_tiny_fast(void* ptr) {
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if (__builtin_expect(!ptr, 0)) return 0;
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#ifdef HAKMEM_TINY_HEADER_CLASSIDX
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// 1. ページ境界ガード:
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// ptr がページ先頭 (offset==0) の場合、ptr-1 は別ページか未マップ領域になる可能性がある。
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// その場合はヘッダ読みを行わず、通常 free 経路にフォールバックする。
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uintptr_t off = (uintptr_t)ptr & 0xFFFu;
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if (__builtin_expect(off == 0, 0)) {
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return 0;
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}
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// 2. Fast header magic validation (必須)
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// Release ビルドでは tiny_region_id_read_header() が magic を省略するため、
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// ここで自前に Tiny 専用ヘッダ (0xA0) を検証しておく。
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uint8_t* header_ptr = (uint8_t*)ptr - 1;
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uint8_t header = *header_ptr;
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uint8_t magic = header & 0xF0u;
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if (__builtin_expect(magic != HEADER_MAGIC, 0)) {
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// Tiny ヘッダではない → Mid/Large/外部ポインタなので通常 free 経路へ
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return 0;
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}
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// 3. class_idx 抽出（下位4bit）
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int class_idx = (int)(header & HEADER_CLASS_MASK);
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if (__builtin_expect(class_idx < 0 || class_idx >= TINY_NUM_CLASSES, 0)) {
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return 0;
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}
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// 4. BASE を計算して Unified Cache に push
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void* base = (void*)((char*)ptr - 1);
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// 5. Superslab 登録確認（誤分類防止）
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SuperSlab* ss_guard = hak_super_lookup(ptr);
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if (__builtin_expect(!(ss_guard && ss_guard->magic == SUPERSLAB_MAGIC), 0)) {
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return 0; // hakmem 管理外 → 通常 free 経路へ
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}
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// Cross-thread free detection (Larson MT crash fix, ENV gated)
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{
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static __thread int g_larson_fix = -1;
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if (__builtin_expect(g_larson_fix == -1, 0)) {
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const char* e = getenv("HAKMEM_TINY_LARSON_FIX");
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g_larson_fix = (e && *e && *e != '0') ? 1 : 0;
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#if !HAKMEM_BUILD_RELEASE
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fprintf(stderr, "[LARSON_FIX_INIT] g_larson_fix=%d (env=%s)\n", g_larson_fix, e ? e : "NULL");
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fflush(stderr);
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#endif
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}
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if (__builtin_expect(g_larson_fix, 0)) {
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// Phase 12 optimization: Use fast mask-based lookup (~5-10 cycles vs 50-100)
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SuperSlab* ss = ss_fast_lookup(base);
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if (ss) {
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int slab_idx = slab_index_for(ss, base);
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if (__builtin_expect(slab_idx >= 0 && slab_idx < ss_slabs_capacity(ss), 1)) {
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uint32_t self_tid = tiny_self_u32_local();
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uint8_t owner_tid_low = ss_slab_meta_owner_tid_low_get(ss, slab_idx);
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// LARSON FIX: Use bits 8-15 for comparison (pthread TIDs aligned to 256 bytes)
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uint8_t self_tid_cmp = (uint8_t)((self_tid >> 8) & 0xFFu);
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#if !HAKMEM_BUILD_RELEASE
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static _Atomic uint64_t g_owner_check_count = 0;
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uint64_t oc = atomic_fetch_add(&g_owner_check_count, 1);
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if (oc < 10) {
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fprintf(stderr, "[LARSON_FIX] Owner check: ptr=%p owner_tid_low=0x%02x self_tid_cmp=0x%02x self_tid=0x%08x match=%d\n",
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ptr, owner_tid_low, self_tid_cmp, self_tid, (owner_tid_low == self_tid_cmp));
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fflush(stderr);
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}
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#endif
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if (__builtin_expect(owner_tid_low != self_tid_cmp, 0)) {
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// Cross-thread free → route to remote queue instead of poisoning TLS cache
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#if !HAKMEM_BUILD_RELEASE
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static _Atomic uint64_t g_cross_thread_count = 0;
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uint64_t ct = atomic_fetch_add(&g_cross_thread_count, 1);
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if (ct < 20) {
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fprintf(stderr, "[LARSON_FIX] Cross-thread free detected! ptr=%p owner_tid_low=0x%02x self_tid_cmp=0x%02x self_tid=0x%08x\n",
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ptr, owner_tid_low, self_tid_cmp, self_tid);
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fflush(stderr);
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}
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#endif
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TinySlabMeta* meta = &ss->slabs[slab_idx];
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if (tiny_free_remote_box(ss, slab_idx, meta, ptr, self_tid)) {
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return 1; // handled via remote queue
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}
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return 0; // remote push failed; fall back to normal path
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}
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}
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}
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}
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}
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// Debug: Log free operations (first 5000, all classes)
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#if !HAKMEM_BUILD_RELEASE
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{
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extern _Atomic uint64_t g_debug_op_count;
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extern __thread TinyTLSSLL g_tls_sll[];
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uint64_t op = atomic_fetch_add(&g_debug_op_count, 1);
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// Note: Shares g_debug_op_count with alloc logging, so bump the window.
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if (op < 5000) {
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fprintf(stderr, "[OP#%04lu FREE] cls=%d ptr=%p base=%p from=free_tiny_fast tls_count_before=%u\n",
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(unsigned long)op, class_idx, ptr, base,
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g_tls_sll[class_idx].count);
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fflush(stderr);
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}
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}
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#endif
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int pushed = unified_cache_push(class_idx, base);
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if (__builtin_expect(pushed, 1)) {
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return 1; // Success
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}
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// Unified Cache full → 通常 free 経路へ
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return 0;
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#else
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// No header mode - fall back to normal free
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return 0;
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#endif
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}
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#endif // HAK_FRONT_MALLOC_TINY_FAST_H
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