Files
hakmem/core/front/malloc_tiny_fast.h
Moe Charm (CI) 0c0d9c8c0b Unify Unified Cache API to BASE-only pointer type with Phantom typing
Core Changes:
- Modified: core/front/tiny_unified_cache.h
  * API signatures changed to use hak_base_ptr_t (Phantom type)
  * unified_cache_pop() returns hak_base_ptr_t (was void*)
  * unified_cache_push() accepts hak_base_ptr_t base (was void*)
  * unified_cache_pop_or_refill() returns hak_base_ptr_t (was void*)
  * Added #include "../box/ptr_type_box.h" for Phantom types

- Modified: core/front/tiny_unified_cache.c
  * unified_cache_refill() return type changed to hak_base_ptr_t
  * Uses HAK_BASE_FROM_RAW() for wrapping return values
  * Uses HAK_BASE_TO_RAW() for unwrapping parameters
  * Maintains internal void* storage in slots array

- Modified: core/box/tiny_front_cold_box.h
  * Uses hak_base_ptr_t from unified_cache_refill()
  * Uses hak_base_is_null() for NULL checks
  * Maintains tiny_user_offset() for BASE→USER conversion
  * Cold path refill integration updated to Phantom types

- Modified: core/front/malloc_tiny_fast.h
  * Free path wraps BASE pointer with HAK_BASE_FROM_RAW()
  * When pushing to Unified Cache via unified_cache_push()

Design Rationale:
- Unified Cache API now exclusively handles BASE pointers (no USER mixing)
- Phantom types enforce type distinction at compile time (debug mode)
- Zero runtime overhead in Release mode (macros expand to identity)
- Hot paths (tiny_hot_alloc_fast, tiny_hot_free_fast) remain unchanged
- Layout consistency maintained via tiny_user_offset() Box

Validation:
- All 25 Phantom type usage sites verified (25/25 correct)
- HAK_BASE_FROM_RAW(): 5/5 correct wrappings
- HAK_BASE_TO_RAW(): 1/1 correct unwrapping
- hak_base_is_null(): 4/4 correct NULL checks
- Compilation: RELEASE=0 and RELEASE=1 both successful
- Smoke tests: 3/3 passed (simple_alloc, loop 10M, pool_tls)

Type Safety Benefits:
- Prevents USER/BASE pointer confusion at API boundaries
- Compile-time checking in debug builds via Phantom struct
- Zero cost abstraction in release builds
- Clear intent: Unified Cache exclusively stores BASE pointers

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
2025-12-04 12:20:21 +09:00

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