1da8754d45
**問題:**
- Larson 4T で 100% SEGV (1T は 2.09M ops/s で完走)
- System/mimalloc は 4T で 33.52M ops/s 正常動作
- SS OFF + Remote OFF でも 4T で SEGV
**根本原因: (Task agent ultrathink 調査結果)**
```
CRASH: mov (%r15),%r13
R15 = 0x6261 ← ASCII "ba" (ゴミ値、未初期化TLS)
```
Worker スレッドの TLS 変数が未初期化:
- `__thread void* g_tls_sll_head[TINY_NUM_CLASSES];` ← 初期化なし
- pthread_create() で生成されたスレッドでゼロ初期化されない
- NULL チェックが通過 (0x6261 != NULL) → dereference → SEGV
**修正内容:**
全 TLS 配列に明示的初期化子 `= {0}` を追加:
1. **core/hakmem_tiny.c:**
- `g_tls_sll_head[TINY_NUM_CLASSES] = {0}`
- `g_tls_sll_count[TINY_NUM_CLASSES] = {0}`
- `g_tls_live_ss[TINY_NUM_CLASSES] = {0}`
- `g_tls_bcur[TINY_NUM_CLASSES] = {0}`
- `g_tls_bend[TINY_NUM_CLASSES] = {0}`
2. **core/tiny_fastcache.c:**
- `g_tiny_fast_cache[TINY_FAST_CLASS_COUNT] = {0}`
- `g_tiny_fast_count[TINY_FAST_CLASS_COUNT] = {0}`
- `g_tiny_fast_free_head[TINY_FAST_CLASS_COUNT] = {0}`
- `g_tiny_fast_free_count[TINY_FAST_CLASS_COUNT] = {0}`
3. **core/hakmem_tiny_magazine.c:**
- `g_tls_mags[TINY_NUM_CLASSES] = {0}`
4. **core/tiny_sticky.c:**
- `g_tls_sticky_ss[TINY_NUM_CLASSES][TINY_STICKY_RING] = {0}`
- `g_tls_sticky_idx[TINY_NUM_CLASSES][TINY_STICKY_RING] = {0}`
- `g_tls_sticky_pos[TINY_NUM_CLASSES] = {0}`
**効果:**
```
Before: 1T: 2.09M ✅ | 4T: SEGV 💀
After: 1T: 2.41M ✅ | 4T: 4.19M ✅ (+15% 1T, SEGV解消)
```
**テスト:**
```bash
# 1 thread: 完走
./larson_hakmem 2 8 128 1024 1 12345 1
→ Throughput = 2,407,597 ops/s ✅
# 4 threads: 完走（以前は SEGV）
./larson_hakmem 2 8 128 1024 1 12345 4
→ Throughput = 4,192,155 ops/s ✅
```
**調査協力:** Task agent (ultrathink mode) による完璧な根本原因特定
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
42 lines
1.6 KiB
C
42 lines
1.6 KiB
C
#include "free_local_box.h"
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#include "free_publish_box.h"
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#include "hakmem_tiny.h"
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void tiny_free_local_box(SuperSlab* ss, int slab_idx, TinySlabMeta* meta, void* ptr, uint32_t my_tid) {
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extern _Atomic uint64_t g_free_local_box_calls;
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atomic_fetch_add_explicit(&g_free_local_box_calls, 1, memory_order_relaxed);
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if (!(ss && ss->magic == SUPERSLAB_MAGIC)) return;
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if (slab_idx < 0 || slab_idx >= ss_slabs_capacity(ss)) return;
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(void)my_tid;
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void* prev = meta->freelist;
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*(void**)ptr = prev;
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meta->freelist = ptr;
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// BUGFIX: Memory barrier to ensure freelist visibility before used decrement
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// Without this, other threads can see new freelist but old used count (race)
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atomic_thread_fence(memory_order_release);
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// Optional freelist mask update on first push
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do {
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static int g_mask_en = -1;
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if (__builtin_expect(g_mask_en == -1, 0)) {
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const char* e = getenv("HAKMEM_TINY_FREELIST_MASK");
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g_mask_en = (e && *e && *e != '0') ? 1 : 0;
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}
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if (__builtin_expect(g_mask_en, 0) && prev == NULL) {
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uint32_t bit = (1u << slab_idx);
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atomic_fetch_or_explicit(&ss->freelist_mask, bit, memory_order_release);
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}
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} while (0);
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// Track local free (debug helpers may be no-op)
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tiny_remote_track_on_local_free(ss, slab_idx, ptr, "local_free", my_tid);
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meta->used--;
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ss_active_dec_one(ss);
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if (prev == NULL) {
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// First-free → advertise slab to adopters
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tiny_free_publish_first_free((int)ss->size_class, ss, slab_idx);
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}
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}
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