Files
hakmem/core/box/free_remote_box.c
Moe Charm (CI) 1da8754d45 CRITICAL FIX: TLS 未初期化による 4T SEGV を完全解消
**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>
2025-11-07 01:27:04 +09:00

23 lines
978 B
C

#include "free_remote_box.h"
#include "free_publish_box.h"
#include "hakmem_tiny.h"
int tiny_free_remote_box(SuperSlab* ss, int slab_idx, TinySlabMeta* meta, void* ptr, uint32_t my_tid) {
extern _Atomic uint64_t g_free_remote_box_calls;
atomic_fetch_add_explicit(&g_free_remote_box_calls, 1, memory_order_relaxed);
if (!(ss && ss->magic == SUPERSLAB_MAGIC)) return 0;
if (slab_idx < 0 || slab_idx >= ss_slabs_capacity(ss)) return 0;
(void)my_tid;
// BUGFIX: Decrement used BEFORE remote push to maintain visibility consistency
// Remote push uses memory_order_release, so drainer must see updated used count
meta->used--;
int transitioned = ss_remote_push(ss, slab_idx, ptr); // ss_active_dec_one() called inside
// ss_active_dec_one(ss); // REMOVED: Already called inside ss_remote_push()
if (transitioned) {
tiny_free_publish_remote_transition((int)ss->size_class, ss, slab_idx);
return 1;
}
return 0;
}