1 //===-- sanitizer_allocator.h -----------------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // Specialized memory allocator for ThreadSanitizer, MemorySanitizer, etc. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef SANITIZER_ALLOCATOR_H 15 #define SANITIZER_ALLOCATOR_H 16 17 #include "sanitizer_internal_defs.h" 18 #include "sanitizer_common.h" 19 #include "sanitizer_libc.h" 20 #include "sanitizer_list.h" 21 #include "sanitizer_mutex.h" 22 #include "sanitizer_lfstack.h" 23 24 namespace __sanitizer { 25 26 // Prints error message and kills the program. 27 void NORETURN ReportAllocatorCannotReturnNull(); 28 29 // SizeClassMap maps allocation sizes into size classes and back. 30 // Class 0 corresponds to size 0. 31 // Classes 1 - 16 correspond to sizes 16 to 256 (size = class_id * 16). 32 // Next 4 classes: 256 + i * 64 (i = 1 to 4). 33 // Next 4 classes: 512 + i * 128 (i = 1 to 4). 34 // ... 35 // Next 4 classes: 2^k + i * 2^(k-2) (i = 1 to 4). 36 // Last class corresponds to kMaxSize = 1 << kMaxSizeLog. 37 // 38 // This structure of the size class map gives us: 39 // - Efficient table-free class-to-size and size-to-class functions. 40 // - Difference between two consequent size classes is betweed 14% and 25% 41 // 42 // This class also gives a hint to a thread-caching allocator about the amount 43 // of chunks that need to be cached per-thread: 44 // - kMaxNumCached is the maximal number of chunks per size class. 45 // - (1 << kMaxBytesCachedLog) is the maximal number of bytes per size class. 46 // 47 // Part of output of SizeClassMap::Print(): 48 // c00 => s: 0 diff: +0 00% l 0 cached: 0 0; id 0 49 // c01 => s: 16 diff: +16 00% l 4 cached: 256 4096; id 1 50 // c02 => s: 32 diff: +16 100% l 5 cached: 256 8192; id 2 51 // c03 => s: 48 diff: +16 50% l 5 cached: 256 12288; id 3 52 // c04 => s: 64 diff: +16 33% l 6 cached: 256 16384; id 4 53 // c05 => s: 80 diff: +16 25% l 6 cached: 256 20480; id 5 54 // c06 => s: 96 diff: +16 20% l 6 cached: 256 24576; id 6 55 // c07 => s: 112 diff: +16 16% l 6 cached: 256 28672; id 7 56 // 57 // c08 => s: 128 diff: +16 14% l 7 cached: 256 32768; id 8 58 // c09 => s: 144 diff: +16 12% l 7 cached: 256 36864; id 9 59 // c10 => s: 160 diff: +16 11% l 7 cached: 256 40960; id 10 60 // c11 => s: 176 diff: +16 10% l 7 cached: 256 45056; id 11 61 // c12 => s: 192 diff: +16 09% l 7 cached: 256 49152; id 12 62 // c13 => s: 208 diff: +16 08% l 7 cached: 256 53248; id 13 63 // c14 => s: 224 diff: +16 07% l 7 cached: 256 57344; id 14 64 // c15 => s: 240 diff: +16 07% l 7 cached: 256 61440; id 15 65 // 66 // c16 => s: 256 diff: +16 06% l 8 cached: 256 65536; id 16 67 // c17 => s: 320 diff: +64 25% l 8 cached: 204 65280; id 17 68 // c18 => s: 384 diff: +64 20% l 8 cached: 170 65280; id 18 69 // c19 => s: 448 diff: +64 16% l 8 cached: 146 65408; id 19 70 // 71 // c20 => s: 512 diff: +64 14% l 9 cached: 128 65536; id 20 72 // c21 => s: 640 diff: +128 25% l 9 cached: 102 65280; id 21 73 // c22 => s: 768 diff: +128 20% l 9 cached: 85 65280; id 22 74 // c23 => s: 896 diff: +128 16% l 9 cached: 73 65408; id 23 75 // 76 // c24 => s: 1024 diff: +128 14% l 10 cached: 64 65536; id 24 77 // c25 => s: 1280 diff: +256 25% l 10 cached: 51 65280; id 25 78 // c26 => s: 1536 diff: +256 20% l 10 cached: 42 64512; id 26 79 // c27 => s: 1792 diff: +256 16% l 10 cached: 36 64512; id 27 80 // 81 // ... 82 // 83 // c48 => s: 65536 diff: +8192 14% l 16 cached: 1 65536; id 48 84 // c49 => s: 81920 diff: +16384 25% l 16 cached: 1 81920; id 49 85 // c50 => s: 98304 diff: +16384 20% l 16 cached: 1 98304; id 50 86 // c51 => s: 114688 diff: +16384 16% l 16 cached: 1 114688; id 51 87 // 88 // c52 => s: 131072 diff: +16384 14% l 17 cached: 1 131072; id 52 89 90 template <uptr kMaxSizeLog, uptr kMaxNumCachedT, uptr kMaxBytesCachedLog> 91 class SizeClassMap { 92 static const uptr kMinSizeLog = 4; 93 static const uptr kMidSizeLog = kMinSizeLog + 4; 94 static const uptr kMinSize = 1 << kMinSizeLog; 95 static const uptr kMidSize = 1 << kMidSizeLog; 96 static const uptr kMidClass = kMidSize / kMinSize; 97 static const uptr S = 2; 98 static const uptr M = (1 << S) - 1; 99 100 public: 101 static const uptr kMaxNumCached = kMaxNumCachedT; 102 // We transfer chunks between central and thread-local free lists in batches. 103 // For small size classes we allocate batches separately. 104 // For large size classes we use one of the chunks to store the batch. 105 struct TransferBatch { 106 TransferBatch *next; 107 uptr count; 108 void *batch[kMaxNumCached]; 109 }; 110 111 static const uptr kMaxSize = 1UL << kMaxSizeLog; 112 static const uptr kNumClasses = 113 kMidClass + ((kMaxSizeLog - kMidSizeLog) << S) + 1; 114 COMPILER_CHECK(kNumClasses >= 32 && kNumClasses <= 256); 115 static const uptr kNumClassesRounded = 116 kNumClasses == 32 ? 32 : 117 kNumClasses <= 64 ? 64 : 118 kNumClasses <= 128 ? 128 : 256; 119 120 static uptr Size(uptr class_id) { 121 if (class_id <= kMidClass) 122 return kMinSize * class_id; 123 class_id -= kMidClass; 124 uptr t = kMidSize << (class_id >> S); 125 return t + (t >> S) * (class_id & M); 126 } 127 128 static uptr ClassID(uptr size) { 129 if (size <= kMidSize) 130 return (size + kMinSize - 1) >> kMinSizeLog; 131 if (size > kMaxSize) return 0; 132 uptr l = MostSignificantSetBitIndex(size); 133 uptr hbits = (size >> (l - S)) & M; 134 uptr lbits = size & ((1 << (l - S)) - 1); 135 uptr l1 = l - kMidSizeLog; 136 return kMidClass + (l1 << S) + hbits + (lbits > 0); 137 } 138 139 static uptr MaxCached(uptr class_id) { 140 if (class_id == 0) return 0; 141 uptr n = (1UL << kMaxBytesCachedLog) / Size(class_id); 142 return Max<uptr>(1, Min(kMaxNumCached, n)); 143 } 144 145 static void Print() { 146 uptr prev_s = 0; 147 uptr total_cached = 0; 148 for (uptr i = 0; i < kNumClasses; i++) { 149 uptr s = Size(i); 150 if (s >= kMidSize / 2 && (s & (s - 1)) == 0) 151 Printf("\n"); 152 uptr d = s - prev_s; 153 uptr p = prev_s ? (d * 100 / prev_s) : 0; 154 uptr l = s ? MostSignificantSetBitIndex(s) : 0; 155 uptr cached = MaxCached(i) * s; 156 Printf("c%02zd => s: %zd diff: +%zd %02zd%% l %zd " 157 "cached: %zd %zd; id %zd\n", 158 i, Size(i), d, p, l, MaxCached(i), cached, ClassID(s)); 159 total_cached += cached; 160 prev_s = s; 161 } 162 Printf("Total cached: %zd\n", total_cached); 163 } 164 165 static bool SizeClassRequiresSeparateTransferBatch(uptr class_id) { 166 return Size(class_id) < sizeof(TransferBatch) - 167 sizeof(uptr) * (kMaxNumCached - MaxCached(class_id)); 168 } 169 170 static void Validate() { 171 for (uptr c = 1; c < kNumClasses; c++) { 172 // Printf("Validate: c%zd\n", c); 173 uptr s = Size(c); 174 CHECK_NE(s, 0U); 175 CHECK_EQ(ClassID(s), c); 176 if (c != kNumClasses - 1) 177 CHECK_EQ(ClassID(s + 1), c + 1); 178 CHECK_EQ(ClassID(s - 1), c); 179 if (c) 180 CHECK_GT(Size(c), Size(c-1)); 181 } 182 CHECK_EQ(ClassID(kMaxSize + 1), 0); 183 184 for (uptr s = 1; s <= kMaxSize; s++) { 185 uptr c = ClassID(s); 186 // Printf("s%zd => c%zd\n", s, c); 187 CHECK_LT(c, kNumClasses); 188 CHECK_GE(Size(c), s); 189 if (c > 0) 190 CHECK_LT(Size(c-1), s); 191 } 192 } 193 }; 194 195 typedef SizeClassMap<17, 128, 16> DefaultSizeClassMap; 196 typedef SizeClassMap<17, 64, 14> CompactSizeClassMap; 197 template<class SizeClassAllocator> struct SizeClassAllocatorLocalCache; 198 199 // Memory allocator statistics 200 enum AllocatorStat { 201 AllocatorStatAllocated, 202 AllocatorStatMapped, 203 AllocatorStatCount 204 }; 205 206 typedef uptr AllocatorStatCounters[AllocatorStatCount]; 207 208 // Per-thread stats, live in per-thread cache. 209 class AllocatorStats { 210 public: 211 void Init() { 212 internal_memset(this, 0, sizeof(*this)); 213 } 214 void InitLinkerInitialized() {} 215 216 void Add(AllocatorStat i, uptr v) { 217 v += atomic_load(&stats_[i], memory_order_relaxed); 218 atomic_store(&stats_[i], v, memory_order_relaxed); 219 } 220 221 void Sub(AllocatorStat i, uptr v) { 222 v = atomic_load(&stats_[i], memory_order_relaxed) - v; 223 atomic_store(&stats_[i], v, memory_order_relaxed); 224 } 225 226 void Set(AllocatorStat i, uptr v) { 227 atomic_store(&stats_[i], v, memory_order_relaxed); 228 } 229 230 uptr Get(AllocatorStat i) const { 231 return atomic_load(&stats_[i], memory_order_relaxed); 232 } 233 234 private: 235 friend class AllocatorGlobalStats; 236 AllocatorStats *next_; 237 AllocatorStats *prev_; 238 atomic_uintptr_t stats_[AllocatorStatCount]; 239 }; 240 241 // Global stats, used for aggregation and querying. 242 class AllocatorGlobalStats : public AllocatorStats { 243 public: 244 void InitLinkerInitialized() { 245 next_ = this; 246 prev_ = this; 247 } 248 void Init() { 249 internal_memset(this, 0, sizeof(*this)); 250 InitLinkerInitialized(); 251 } 252 253 void Register(AllocatorStats *s) { 254 SpinMutexLock l(&mu_); 255 s->next_ = next_; 256 s->prev_ = this; 257 next_->prev_ = s; 258 next_ = s; 259 } 260 261 void Unregister(AllocatorStats *s) { 262 SpinMutexLock l(&mu_); 263 s->prev_->next_ = s->next_; 264 s->next_->prev_ = s->prev_; 265 for (int i = 0; i < AllocatorStatCount; i++) 266 Add(AllocatorStat(i), s->Get(AllocatorStat(i))); 267 } 268 269 void Get(AllocatorStatCounters s) const { 270 internal_memset(s, 0, AllocatorStatCount * sizeof(uptr)); 271 SpinMutexLock l(&mu_); 272 const AllocatorStats *stats = this; 273 for (;;) { 274 for (int i = 0; i < AllocatorStatCount; i++) 275 s[i] += stats->Get(AllocatorStat(i)); 276 stats = stats->next_; 277 if (stats == this) 278 break; 279 } 280 // All stats must be non-negative. 281 for (int i = 0; i < AllocatorStatCount; i++) 282 s[i] = ((sptr)s[i]) >= 0 ? s[i] : 0; 283 } 284 285 private: 286 mutable SpinMutex mu_; 287 }; 288 289 // Allocators call these callbacks on mmap/munmap. 290 struct NoOpMapUnmapCallback { 291 void OnMap(uptr p, uptr size) const { } 292 void OnUnmap(uptr p, uptr size) const { } 293 }; 294 295 // Callback type for iterating over chunks. 296 typedef void (*ForEachChunkCallback)(uptr chunk, void *arg); 297 298 // SizeClassAllocator64 -- allocator for 64-bit address space. 299 // 300 // Space: a portion of address space of kSpaceSize bytes starting at 301 // a fixed address (kSpaceBeg). Both constants are powers of two and 302 // kSpaceBeg is kSpaceSize-aligned. 303 // At the beginning the entire space is mprotect-ed, then small parts of it 304 // are mapped on demand. 305 // 306 // Region: a part of Space dedicated to a single size class. 307 // There are kNumClasses Regions of equal size. 308 // 309 // UserChunk: a piece of memory returned to user. 310 // MetaChunk: kMetadataSize bytes of metadata associated with a UserChunk. 311 // 312 // A Region looks like this: 313 // UserChunk1 ... UserChunkN <gap> MetaChunkN ... MetaChunk1 314 template <const uptr kSpaceBeg, const uptr kSpaceSize, 315 const uptr kMetadataSize, class SizeClassMap, 316 class MapUnmapCallback = NoOpMapUnmapCallback> 317 class SizeClassAllocator64 { 318 public: 319 typedef typename SizeClassMap::TransferBatch Batch; 320 typedef SizeClassAllocator64<kSpaceBeg, kSpaceSize, kMetadataSize, 321 SizeClassMap, MapUnmapCallback> ThisT; 322 typedef SizeClassAllocatorLocalCache<ThisT> AllocatorCache; 323 324 void Init() { 325 CHECK_EQ(kSpaceBeg, 326 reinterpret_cast<uptr>(MmapNoAccess(kSpaceBeg, kSpaceSize))); 327 MapWithCallback(kSpaceEnd, AdditionalSize()); 328 } 329 330 void MapWithCallback(uptr beg, uptr size) { 331 CHECK_EQ(beg, reinterpret_cast<uptr>(MmapFixedOrDie(beg, size))); 332 MapUnmapCallback().OnMap(beg, size); 333 } 334 335 void UnmapWithCallback(uptr beg, uptr size) { 336 MapUnmapCallback().OnUnmap(beg, size); 337 UnmapOrDie(reinterpret_cast<void *>(beg), size); 338 } 339 340 static bool CanAllocate(uptr size, uptr alignment) { 341 return size <= SizeClassMap::kMaxSize && 342 alignment <= SizeClassMap::kMaxSize; 343 } 344 345 NOINLINE Batch* AllocateBatch(AllocatorStats *stat, AllocatorCache *c, 346 uptr class_id) { 347 CHECK_LT(class_id, kNumClasses); 348 RegionInfo *region = GetRegionInfo(class_id); 349 Batch *b = region->free_list.Pop(); 350 if (b == 0) 351 b = PopulateFreeList(stat, c, class_id, region); 352 region->n_allocated += b->count; 353 return b; 354 } 355 356 NOINLINE void DeallocateBatch(AllocatorStats *stat, uptr class_id, Batch *b) { 357 RegionInfo *region = GetRegionInfo(class_id); 358 CHECK_GT(b->count, 0); 359 region->free_list.Push(b); 360 region->n_freed += b->count; 361 } 362 363 static bool PointerIsMine(const void *p) { 364 return reinterpret_cast<uptr>(p) / kSpaceSize == kSpaceBeg / kSpaceSize; 365 } 366 367 static uptr GetSizeClass(const void *p) { 368 return (reinterpret_cast<uptr>(p) / kRegionSize) % kNumClassesRounded; 369 } 370 371 void *GetBlockBegin(const void *p) { 372 uptr class_id = GetSizeClass(p); 373 uptr size = SizeClassMap::Size(class_id); 374 if (!size) return 0; 375 uptr chunk_idx = GetChunkIdx((uptr)p, size); 376 uptr reg_beg = (uptr)p & ~(kRegionSize - 1); 377 uptr beg = chunk_idx * size; 378 uptr next_beg = beg + size; 379 if (class_id >= kNumClasses) return 0; 380 RegionInfo *region = GetRegionInfo(class_id); 381 if (region->mapped_user >= next_beg) 382 return reinterpret_cast<void*>(reg_beg + beg); 383 return 0; 384 } 385 386 static uptr GetActuallyAllocatedSize(void *p) { 387 CHECK(PointerIsMine(p)); 388 return SizeClassMap::Size(GetSizeClass(p)); 389 } 390 391 uptr ClassID(uptr size) { return SizeClassMap::ClassID(size); } 392 393 void *GetMetaData(const void *p) { 394 uptr class_id = GetSizeClass(p); 395 uptr size = SizeClassMap::Size(class_id); 396 uptr chunk_idx = GetChunkIdx(reinterpret_cast<uptr>(p), size); 397 return reinterpret_cast<void*>(kSpaceBeg + (kRegionSize * (class_id + 1)) - 398 (1 + chunk_idx) * kMetadataSize); 399 } 400 401 uptr TotalMemoryUsed() { 402 uptr res = 0; 403 for (uptr i = 0; i < kNumClasses; i++) 404 res += GetRegionInfo(i)->allocated_user; 405 return res; 406 } 407 408 // Test-only. 409 void TestOnlyUnmap() { 410 UnmapWithCallback(kSpaceBeg, kSpaceSize + AdditionalSize()); 411 } 412 413 void PrintStats() { 414 uptr total_mapped = 0; 415 uptr n_allocated = 0; 416 uptr n_freed = 0; 417 for (uptr class_id = 1; class_id < kNumClasses; class_id++) { 418 RegionInfo *region = GetRegionInfo(class_id); 419 total_mapped += region->mapped_user; 420 n_allocated += region->n_allocated; 421 n_freed += region->n_freed; 422 } 423 Printf("Stats: SizeClassAllocator64: %zdM mapped in %zd allocations; " 424 "remains %zd\n", 425 total_mapped >> 20, n_allocated, n_allocated - n_freed); 426 for (uptr class_id = 1; class_id < kNumClasses; class_id++) { 427 RegionInfo *region = GetRegionInfo(class_id); 428 if (region->mapped_user == 0) continue; 429 Printf(" %02zd (%zd): total: %zd K allocs: %zd remains: %zd\n", 430 class_id, 431 SizeClassMap::Size(class_id), 432 region->mapped_user >> 10, 433 region->n_allocated, 434 region->n_allocated - region->n_freed); 435 } 436 } 437 438 // ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone 439 // introspection API. 440 void ForceLock() { 441 for (uptr i = 0; i < kNumClasses; i++) { 442 GetRegionInfo(i)->mutex.Lock(); 443 } 444 } 445 446 void ForceUnlock() { 447 for (int i = (int)kNumClasses - 1; i >= 0; i--) { 448 GetRegionInfo(i)->mutex.Unlock(); 449 } 450 } 451 452 // Iterate over all existing chunks. 453 // The allocator must be locked when calling this function. 454 void ForEachChunk(ForEachChunkCallback callback, void *arg) { 455 for (uptr class_id = 1; class_id < kNumClasses; class_id++) { 456 RegionInfo *region = GetRegionInfo(class_id); 457 uptr chunk_size = SizeClassMap::Size(class_id); 458 uptr region_beg = kSpaceBeg + class_id * kRegionSize; 459 for (uptr chunk = region_beg; 460 chunk < region_beg + region->allocated_user; 461 chunk += chunk_size) { 462 // Too slow: CHECK_EQ((void *)chunk, GetBlockBegin((void *)chunk)); 463 callback(chunk, arg); 464 } 465 } 466 } 467 468 static uptr AdditionalSize() { 469 return RoundUpTo(sizeof(RegionInfo) * kNumClassesRounded, 470 GetPageSizeCached()); 471 } 472 473 typedef SizeClassMap SizeClassMapT; 474 static const uptr kNumClasses = SizeClassMap::kNumClasses; 475 static const uptr kNumClassesRounded = SizeClassMap::kNumClassesRounded; 476 477 private: 478 static const uptr kRegionSize = kSpaceSize / kNumClassesRounded; 479 static const uptr kSpaceEnd = kSpaceBeg + kSpaceSize; 480 COMPILER_CHECK(kSpaceBeg % kSpaceSize == 0); 481 // kRegionSize must be >= 2^32. 482 COMPILER_CHECK((kRegionSize) >= (1ULL << (SANITIZER_WORDSIZE / 2))); 483 // Populate the free list with at most this number of bytes at once 484 // or with one element if its size is greater. 485 static const uptr kPopulateSize = 1 << 14; 486 // Call mmap for user memory with at least this size. 487 static const uptr kUserMapSize = 1 << 16; 488 // Call mmap for metadata memory with at least this size. 489 static const uptr kMetaMapSize = 1 << 16; 490 491 struct RegionInfo { 492 BlockingMutex mutex; 493 LFStack<Batch> free_list; 494 uptr allocated_user; // Bytes allocated for user memory. 495 uptr allocated_meta; // Bytes allocated for metadata. 496 uptr mapped_user; // Bytes mapped for user memory. 497 uptr mapped_meta; // Bytes mapped for metadata. 498 uptr n_allocated, n_freed; // Just stats. 499 }; 500 COMPILER_CHECK(sizeof(RegionInfo) >= kCacheLineSize); 501 502 RegionInfo *GetRegionInfo(uptr class_id) { 503 CHECK_LT(class_id, kNumClasses); 504 RegionInfo *regions = reinterpret_cast<RegionInfo*>(kSpaceBeg + kSpaceSize); 505 return ®ions[class_id]; 506 } 507 508 static uptr GetChunkIdx(uptr chunk, uptr size) { 509 uptr offset = chunk % kRegionSize; 510 // Here we divide by a non-constant. This is costly. 511 // size always fits into 32-bits. If the offset fits too, use 32-bit div. 512 if (offset >> (SANITIZER_WORDSIZE / 2)) 513 return offset / size; 514 return (u32)offset / (u32)size; 515 } 516 517 NOINLINE Batch* PopulateFreeList(AllocatorStats *stat, AllocatorCache *c, 518 uptr class_id, RegionInfo *region) { 519 BlockingMutexLock l(®ion->mutex); 520 Batch *b = region->free_list.Pop(); 521 if (b) 522 return b; 523 uptr size = SizeClassMap::Size(class_id); 524 uptr count = size < kPopulateSize ? SizeClassMap::MaxCached(class_id) : 1; 525 uptr beg_idx = region->allocated_user; 526 uptr end_idx = beg_idx + count * size; 527 uptr region_beg = kSpaceBeg + kRegionSize * class_id; 528 if (end_idx + size > region->mapped_user) { 529 // Do the mmap for the user memory. 530 uptr map_size = kUserMapSize; 531 while (end_idx + size > region->mapped_user + map_size) 532 map_size += kUserMapSize; 533 CHECK_GE(region->mapped_user + map_size, end_idx); 534 MapWithCallback(region_beg + region->mapped_user, map_size); 535 stat->Add(AllocatorStatMapped, map_size); 536 region->mapped_user += map_size; 537 } 538 uptr total_count = (region->mapped_user - beg_idx - size) 539 / size / count * count; 540 region->allocated_meta += total_count * kMetadataSize; 541 if (region->allocated_meta > region->mapped_meta) { 542 uptr map_size = kMetaMapSize; 543 while (region->allocated_meta > region->mapped_meta + map_size) 544 map_size += kMetaMapSize; 545 // Do the mmap for the metadata. 546 CHECK_GE(region->mapped_meta + map_size, region->allocated_meta); 547 MapWithCallback(region_beg + kRegionSize - 548 region->mapped_meta - map_size, map_size); 549 region->mapped_meta += map_size; 550 } 551 CHECK_LE(region->allocated_meta, region->mapped_meta); 552 if (region->mapped_user + region->mapped_meta > kRegionSize) { 553 Printf("%s: Out of memory. Dying. ", SanitizerToolName); 554 Printf("The process has exhausted %zuMB for size class %zu.\n", 555 kRegionSize / 1024 / 1024, size); 556 Die(); 557 } 558 for (;;) { 559 if (SizeClassMap::SizeClassRequiresSeparateTransferBatch(class_id)) 560 b = (Batch*)c->Allocate(this, SizeClassMap::ClassID(sizeof(Batch))); 561 else 562 b = (Batch*)(region_beg + beg_idx); 563 b->count = count; 564 for (uptr i = 0; i < count; i++) 565 b->batch[i] = (void*)(region_beg + beg_idx + i * size); 566 region->allocated_user += count * size; 567 CHECK_LE(region->allocated_user, region->mapped_user); 568 beg_idx += count * size; 569 if (beg_idx + count * size + size > region->mapped_user) 570 break; 571 CHECK_GT(b->count, 0); 572 region->free_list.Push(b); 573 } 574 return b; 575 } 576 }; 577 578 // Maps integers in rage [0, kSize) to u8 values. 579 template<u64 kSize> 580 class FlatByteMap { 581 public: 582 void TestOnlyInit() { 583 internal_memset(map_, 0, sizeof(map_)); 584 } 585 586 void set(uptr idx, u8 val) { 587 CHECK_LT(idx, kSize); 588 CHECK_EQ(0U, map_[idx]); 589 map_[idx] = val; 590 } 591 u8 operator[] (uptr idx) { 592 CHECK_LT(idx, kSize); 593 // FIXME: CHECK may be too expensive here. 594 return map_[idx]; 595 } 596 private: 597 u8 map_[kSize]; 598 }; 599 600 // TwoLevelByteMap maps integers in range [0, kSize1*kSize2) to u8 values. 601 // It is implemented as a two-dimensional array: array of kSize1 pointers 602 // to kSize2-byte arrays. The secondary arrays are mmaped on demand. 603 // Each value is initially zero and can be set to something else only once. 604 // Setting and getting values from multiple threads is safe w/o extra locking. 605 template <u64 kSize1, u64 kSize2, class MapUnmapCallback = NoOpMapUnmapCallback> 606 class TwoLevelByteMap { 607 public: 608 void TestOnlyInit() { 609 internal_memset(map1_, 0, sizeof(map1_)); 610 mu_.Init(); 611 } 612 void TestOnlyUnmap() { 613 for (uptr i = 0; i < kSize1; i++) { 614 u8 *p = Get(i); 615 if (!p) continue; 616 MapUnmapCallback().OnUnmap(reinterpret_cast<uptr>(p), kSize2); 617 UnmapOrDie(p, kSize2); 618 } 619 } 620 621 uptr size() const { return kSize1 * kSize2; } 622 uptr size1() const { return kSize1; } 623 uptr size2() const { return kSize2; } 624 625 void set(uptr idx, u8 val) { 626 CHECK_LT(idx, kSize1 * kSize2); 627 u8 *map2 = GetOrCreate(idx / kSize2); 628 CHECK_EQ(0U, map2[idx % kSize2]); 629 map2[idx % kSize2] = val; 630 } 631 632 u8 operator[] (uptr idx) const { 633 CHECK_LT(idx, kSize1 * kSize2); 634 u8 *map2 = Get(idx / kSize2); 635 if (!map2) return 0; 636 return map2[idx % kSize2]; 637 } 638 639 private: 640 u8 *Get(uptr idx) const { 641 CHECK_LT(idx, kSize1); 642 return reinterpret_cast<u8 *>( 643 atomic_load(&map1_[idx], memory_order_acquire)); 644 } 645 646 u8 *GetOrCreate(uptr idx) { 647 u8 *res = Get(idx); 648 if (!res) { 649 SpinMutexLock l(&mu_); 650 if (!(res = Get(idx))) { 651 res = (u8*)MmapOrDie(kSize2, "TwoLevelByteMap"); 652 MapUnmapCallback().OnMap(reinterpret_cast<uptr>(res), kSize2); 653 atomic_store(&map1_[idx], reinterpret_cast<uptr>(res), 654 memory_order_release); 655 } 656 } 657 return res; 658 } 659 660 atomic_uintptr_t map1_[kSize1]; 661 StaticSpinMutex mu_; 662 }; 663 664 // SizeClassAllocator32 -- allocator for 32-bit address space. 665 // This allocator can theoretically be used on 64-bit arch, but there it is less 666 // efficient than SizeClassAllocator64. 667 // 668 // [kSpaceBeg, kSpaceBeg + kSpaceSize) is the range of addresses which can 669 // be returned by MmapOrDie(). 670 // 671 // Region: 672 // a result of a single call to MmapAlignedOrDie(kRegionSize, kRegionSize). 673 // Since the regions are aligned by kRegionSize, there are exactly 674 // kNumPossibleRegions possible regions in the address space and so we keep 675 // a ByteMap possible_regions to store the size classes of each Region. 676 // 0 size class means the region is not used by the allocator. 677 // 678 // One Region is used to allocate chunks of a single size class. 679 // A Region looks like this: 680 // UserChunk1 .. UserChunkN <gap> MetaChunkN .. MetaChunk1 681 // 682 // In order to avoid false sharing the objects of this class should be 683 // chache-line aligned. 684 template <const uptr kSpaceBeg, const u64 kSpaceSize, 685 const uptr kMetadataSize, class SizeClassMap, 686 const uptr kRegionSizeLog, 687 class ByteMap, 688 class MapUnmapCallback = NoOpMapUnmapCallback> 689 class SizeClassAllocator32 { 690 public: 691 typedef typename SizeClassMap::TransferBatch Batch; 692 typedef SizeClassAllocator32<kSpaceBeg, kSpaceSize, kMetadataSize, 693 SizeClassMap, kRegionSizeLog, ByteMap, MapUnmapCallback> ThisT; 694 typedef SizeClassAllocatorLocalCache<ThisT> AllocatorCache; 695 696 void Init() { 697 possible_regions.TestOnlyInit(); 698 internal_memset(size_class_info_array, 0, sizeof(size_class_info_array)); 699 } 700 701 void *MapWithCallback(uptr size) { 702 size = RoundUpTo(size, GetPageSizeCached()); 703 void *res = MmapOrDie(size, "SizeClassAllocator32"); 704 MapUnmapCallback().OnMap((uptr)res, size); 705 return res; 706 } 707 708 void UnmapWithCallback(uptr beg, uptr size) { 709 MapUnmapCallback().OnUnmap(beg, size); 710 UnmapOrDie(reinterpret_cast<void *>(beg), size); 711 } 712 713 static bool CanAllocate(uptr size, uptr alignment) { 714 return size <= SizeClassMap::kMaxSize && 715 alignment <= SizeClassMap::kMaxSize; 716 } 717 718 void *GetMetaData(const void *p) { 719 CHECK(PointerIsMine(p)); 720 uptr mem = reinterpret_cast<uptr>(p); 721 uptr beg = ComputeRegionBeg(mem); 722 uptr size = SizeClassMap::Size(GetSizeClass(p)); 723 u32 offset = mem - beg; 724 uptr n = offset / (u32)size; // 32-bit division 725 uptr meta = (beg + kRegionSize) - (n + 1) * kMetadataSize; 726 return reinterpret_cast<void*>(meta); 727 } 728 729 NOINLINE Batch* AllocateBatch(AllocatorStats *stat, AllocatorCache *c, 730 uptr class_id) { 731 CHECK_LT(class_id, kNumClasses); 732 SizeClassInfo *sci = GetSizeClassInfo(class_id); 733 SpinMutexLock l(&sci->mutex); 734 if (sci->free_list.empty()) 735 PopulateFreeList(stat, c, sci, class_id); 736 CHECK(!sci->free_list.empty()); 737 Batch *b = sci->free_list.front(); 738 sci->free_list.pop_front(); 739 return b; 740 } 741 742 NOINLINE void DeallocateBatch(AllocatorStats *stat, uptr class_id, Batch *b) { 743 CHECK_LT(class_id, kNumClasses); 744 SizeClassInfo *sci = GetSizeClassInfo(class_id); 745 SpinMutexLock l(&sci->mutex); 746 CHECK_GT(b->count, 0); 747 sci->free_list.push_front(b); 748 } 749 750 bool PointerIsMine(const void *p) { 751 return GetSizeClass(p) != 0; 752 } 753 754 uptr GetSizeClass(const void *p) { 755 return possible_regions[ComputeRegionId(reinterpret_cast<uptr>(p))]; 756 } 757 758 void *GetBlockBegin(const void *p) { 759 CHECK(PointerIsMine(p)); 760 uptr mem = reinterpret_cast<uptr>(p); 761 uptr beg = ComputeRegionBeg(mem); 762 uptr size = SizeClassMap::Size(GetSizeClass(p)); 763 u32 offset = mem - beg; 764 u32 n = offset / (u32)size; // 32-bit division 765 uptr res = beg + (n * (u32)size); 766 return reinterpret_cast<void*>(res); 767 } 768 769 uptr GetActuallyAllocatedSize(void *p) { 770 CHECK(PointerIsMine(p)); 771 return SizeClassMap::Size(GetSizeClass(p)); 772 } 773 774 uptr ClassID(uptr size) { return SizeClassMap::ClassID(size); } 775 776 uptr TotalMemoryUsed() { 777 // No need to lock here. 778 uptr res = 0; 779 for (uptr i = 0; i < kNumPossibleRegions; i++) 780 if (possible_regions[i]) 781 res += kRegionSize; 782 return res; 783 } 784 785 void TestOnlyUnmap() { 786 for (uptr i = 0; i < kNumPossibleRegions; i++) 787 if (possible_regions[i]) 788 UnmapWithCallback((i * kRegionSize), kRegionSize); 789 } 790 791 // ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone 792 // introspection API. 793 void ForceLock() { 794 for (uptr i = 0; i < kNumClasses; i++) { 795 GetSizeClassInfo(i)->mutex.Lock(); 796 } 797 } 798 799 void ForceUnlock() { 800 for (int i = kNumClasses - 1; i >= 0; i--) { 801 GetSizeClassInfo(i)->mutex.Unlock(); 802 } 803 } 804 805 // Iterate over all existing chunks. 806 // The allocator must be locked when calling this function. 807 void ForEachChunk(ForEachChunkCallback callback, void *arg) { 808 for (uptr region = 0; region < kNumPossibleRegions; region++) 809 if (possible_regions[region]) { 810 uptr chunk_size = SizeClassMap::Size(possible_regions[region]); 811 uptr max_chunks_in_region = kRegionSize / (chunk_size + kMetadataSize); 812 uptr region_beg = region * kRegionSize; 813 for (uptr chunk = region_beg; 814 chunk < region_beg + max_chunks_in_region * chunk_size; 815 chunk += chunk_size) { 816 // Too slow: CHECK_EQ((void *)chunk, GetBlockBegin((void *)chunk)); 817 callback(chunk, arg); 818 } 819 } 820 } 821 822 void PrintStats() { 823 } 824 825 typedef SizeClassMap SizeClassMapT; 826 static const uptr kNumClasses = SizeClassMap::kNumClasses; 827 828 private: 829 static const uptr kRegionSize = 1 << kRegionSizeLog; 830 static const uptr kNumPossibleRegions = kSpaceSize / kRegionSize; 831 832 struct SizeClassInfo { 833 SpinMutex mutex; 834 IntrusiveList<Batch> free_list; 835 char padding[kCacheLineSize - sizeof(uptr) - sizeof(IntrusiveList<Batch>)]; 836 }; 837 COMPILER_CHECK(sizeof(SizeClassInfo) == kCacheLineSize); 838 839 uptr ComputeRegionId(uptr mem) { 840 uptr res = mem >> kRegionSizeLog; 841 CHECK_LT(res, kNumPossibleRegions); 842 return res; 843 } 844 845 uptr ComputeRegionBeg(uptr mem) { 846 return mem & ~(kRegionSize - 1); 847 } 848 849 uptr AllocateRegion(AllocatorStats *stat, uptr class_id) { 850 CHECK_LT(class_id, kNumClasses); 851 uptr res = reinterpret_cast<uptr>(MmapAlignedOrDie(kRegionSize, kRegionSize, 852 "SizeClassAllocator32")); 853 MapUnmapCallback().OnMap(res, kRegionSize); 854 stat->Add(AllocatorStatMapped, kRegionSize); 855 CHECK_EQ(0U, (res & (kRegionSize - 1))); 856 possible_regions.set(ComputeRegionId(res), static_cast<u8>(class_id)); 857 return res; 858 } 859 860 SizeClassInfo *GetSizeClassInfo(uptr class_id) { 861 CHECK_LT(class_id, kNumClasses); 862 return &size_class_info_array[class_id]; 863 } 864 865 void PopulateFreeList(AllocatorStats *stat, AllocatorCache *c, 866 SizeClassInfo *sci, uptr class_id) { 867 uptr size = SizeClassMap::Size(class_id); 868 uptr reg = AllocateRegion(stat, class_id); 869 uptr n_chunks = kRegionSize / (size + kMetadataSize); 870 uptr max_count = SizeClassMap::MaxCached(class_id); 871 Batch *b = 0; 872 for (uptr i = reg; i < reg + n_chunks * size; i += size) { 873 if (b == 0) { 874 if (SizeClassMap::SizeClassRequiresSeparateTransferBatch(class_id)) 875 b = (Batch*)c->Allocate(this, SizeClassMap::ClassID(sizeof(Batch))); 876 else 877 b = (Batch*)i; 878 b->count = 0; 879 } 880 b->batch[b->count++] = (void*)i; 881 if (b->count == max_count) { 882 CHECK_GT(b->count, 0); 883 sci->free_list.push_back(b); 884 b = 0; 885 } 886 } 887 if (b) { 888 CHECK_GT(b->count, 0); 889 sci->free_list.push_back(b); 890 } 891 } 892 893 ByteMap possible_regions; 894 SizeClassInfo size_class_info_array[kNumClasses]; 895 }; 896 897 // Objects of this type should be used as local caches for SizeClassAllocator64 898 // or SizeClassAllocator32. Since the typical use of this class is to have one 899 // object per thread in TLS, is has to be POD. 900 template<class SizeClassAllocator> 901 struct SizeClassAllocatorLocalCache { 902 typedef SizeClassAllocator Allocator; 903 static const uptr kNumClasses = SizeClassAllocator::kNumClasses; 904 905 void Init(AllocatorGlobalStats *s) { 906 stats_.Init(); 907 if (s) 908 s->Register(&stats_); 909 } 910 911 void Destroy(SizeClassAllocator *allocator, AllocatorGlobalStats *s) { 912 Drain(allocator); 913 if (s) 914 s->Unregister(&stats_); 915 } 916 917 void *Allocate(SizeClassAllocator *allocator, uptr class_id) { 918 CHECK_NE(class_id, 0UL); 919 CHECK_LT(class_id, kNumClasses); 920 stats_.Add(AllocatorStatAllocated, SizeClassMap::Size(class_id)); 921 PerClass *c = &per_class_[class_id]; 922 if (UNLIKELY(c->count == 0)) 923 Refill(allocator, class_id); 924 void *res = c->batch[--c->count]; 925 PREFETCH(c->batch[c->count - 1]); 926 return res; 927 } 928 929 void Deallocate(SizeClassAllocator *allocator, uptr class_id, void *p) { 930 CHECK_NE(class_id, 0UL); 931 CHECK_LT(class_id, kNumClasses); 932 // If the first allocator call on a new thread is a deallocation, then 933 // max_count will be zero, leading to check failure. 934 InitCache(); 935 stats_.Sub(AllocatorStatAllocated, SizeClassMap::Size(class_id)); 936 PerClass *c = &per_class_[class_id]; 937 CHECK_NE(c->max_count, 0UL); 938 if (UNLIKELY(c->count == c->max_count)) 939 Drain(allocator, class_id); 940 c->batch[c->count++] = p; 941 } 942 943 void Drain(SizeClassAllocator *allocator) { 944 for (uptr class_id = 0; class_id < kNumClasses; class_id++) { 945 PerClass *c = &per_class_[class_id]; 946 while (c->count > 0) 947 Drain(allocator, class_id); 948 } 949 } 950 951 // private: 952 typedef typename SizeClassAllocator::SizeClassMapT SizeClassMap; 953 typedef typename SizeClassMap::TransferBatch Batch; 954 struct PerClass { 955 uptr count; 956 uptr max_count; 957 void *batch[2 * SizeClassMap::kMaxNumCached]; 958 }; 959 PerClass per_class_[kNumClasses]; 960 AllocatorStats stats_; 961 962 void InitCache() { 963 if (per_class_[1].max_count) 964 return; 965 for (uptr i = 0; i < kNumClasses; i++) { 966 PerClass *c = &per_class_[i]; 967 c->max_count = 2 * SizeClassMap::MaxCached(i); 968 } 969 } 970 971 NOINLINE void Refill(SizeClassAllocator *allocator, uptr class_id) { 972 InitCache(); 973 PerClass *c = &per_class_[class_id]; 974 Batch *b = allocator->AllocateBatch(&stats_, this, class_id); 975 CHECK_GT(b->count, 0); 976 for (uptr i = 0; i < b->count; i++) 977 c->batch[i] = b->batch[i]; 978 c->count = b->count; 979 if (SizeClassMap::SizeClassRequiresSeparateTransferBatch(class_id)) 980 Deallocate(allocator, SizeClassMap::ClassID(sizeof(Batch)), b); 981 } 982 983 NOINLINE void Drain(SizeClassAllocator *allocator, uptr class_id) { 984 InitCache(); 985 PerClass *c = &per_class_[class_id]; 986 Batch *b; 987 if (SizeClassMap::SizeClassRequiresSeparateTransferBatch(class_id)) 988 b = (Batch*)Allocate(allocator, SizeClassMap::ClassID(sizeof(Batch))); 989 else 990 b = (Batch*)c->batch[0]; 991 uptr cnt = Min(c->max_count / 2, c->count); 992 for (uptr i = 0; i < cnt; i++) { 993 b->batch[i] = c->batch[i]; 994 c->batch[i] = c->batch[i + c->max_count / 2]; 995 } 996 b->count = cnt; 997 c->count -= cnt; 998 CHECK_GT(b->count, 0); 999 allocator->DeallocateBatch(&stats_, class_id, b); 1000 } 1001 }; 1002 1003 // This class can (de)allocate only large chunks of memory using mmap/unmap. 1004 // The main purpose of this allocator is to cover large and rare allocation 1005 // sizes not covered by more efficient allocators (e.g. SizeClassAllocator64). 1006 template <class MapUnmapCallback = NoOpMapUnmapCallback> 1007 class LargeMmapAllocator { 1008 public: 1009 void InitLinkerInitialized(bool may_return_null) { 1010 page_size_ = GetPageSizeCached(); 1011 atomic_store(&may_return_null_, may_return_null, memory_order_relaxed); 1012 } 1013 1014 void Init(bool may_return_null) { 1015 internal_memset(this, 0, sizeof(*this)); 1016 InitLinkerInitialized(may_return_null); 1017 } 1018 1019 void *Allocate(AllocatorStats *stat, uptr size, uptr alignment) { 1020 CHECK(IsPowerOfTwo(alignment)); 1021 uptr map_size = RoundUpMapSize(size); 1022 if (alignment > page_size_) 1023 map_size += alignment; 1024 // Overflow. 1025 if (map_size < size) 1026 return ReturnNullOrDie(); 1027 uptr map_beg = reinterpret_cast<uptr>( 1028 MmapOrDie(map_size, "LargeMmapAllocator")); 1029 CHECK(IsAligned(map_beg, page_size_)); 1030 MapUnmapCallback().OnMap(map_beg, map_size); 1031 uptr map_end = map_beg + map_size; 1032 uptr res = map_beg + page_size_; 1033 if (res & (alignment - 1)) // Align. 1034 res += alignment - (res & (alignment - 1)); 1035 CHECK(IsAligned(res, alignment)); 1036 CHECK(IsAligned(res, page_size_)); 1037 CHECK_GE(res + size, map_beg); 1038 CHECK_LE(res + size, map_end); 1039 Header *h = GetHeader(res); 1040 h->size = size; 1041 h->map_beg = map_beg; 1042 h->map_size = map_size; 1043 uptr size_log = MostSignificantSetBitIndex(map_size); 1044 CHECK_LT(size_log, ARRAY_SIZE(stats.by_size_log)); 1045 { 1046 SpinMutexLock l(&mutex_); 1047 uptr idx = n_chunks_++; 1048 chunks_sorted_ = false; 1049 CHECK_LT(idx, kMaxNumChunks); 1050 h->chunk_idx = idx; 1051 chunks_[idx] = h; 1052 stats.n_allocs++; 1053 stats.currently_allocated += map_size; 1054 stats.max_allocated = Max(stats.max_allocated, stats.currently_allocated); 1055 stats.by_size_log[size_log]++; 1056 stat->Add(AllocatorStatAllocated, map_size); 1057 stat->Add(AllocatorStatMapped, map_size); 1058 } 1059 return reinterpret_cast<void*>(res); 1060 } 1061 1062 void *ReturnNullOrDie() { 1063 if (atomic_load(&may_return_null_, memory_order_acquire)) 1064 return 0; 1065 ReportAllocatorCannotReturnNull(); 1066 } 1067 1068 void SetMayReturnNull(bool may_return_null) { 1069 atomic_store(&may_return_null_, may_return_null, memory_order_release); 1070 } 1071 1072 void Deallocate(AllocatorStats *stat, void *p) { 1073 Header *h = GetHeader(p); 1074 { 1075 SpinMutexLock l(&mutex_); 1076 uptr idx = h->chunk_idx; 1077 CHECK_EQ(chunks_[idx], h); 1078 CHECK_LT(idx, n_chunks_); 1079 chunks_[idx] = chunks_[n_chunks_ - 1]; 1080 chunks_[idx]->chunk_idx = idx; 1081 n_chunks_--; 1082 chunks_sorted_ = false; 1083 stats.n_frees++; 1084 stats.currently_allocated -= h->map_size; 1085 stat->Sub(AllocatorStatAllocated, h->map_size); 1086 stat->Sub(AllocatorStatMapped, h->map_size); 1087 } 1088 MapUnmapCallback().OnUnmap(h->map_beg, h->map_size); 1089 UnmapOrDie(reinterpret_cast<void*>(h->map_beg), h->map_size); 1090 } 1091 1092 uptr TotalMemoryUsed() { 1093 SpinMutexLock l(&mutex_); 1094 uptr res = 0; 1095 for (uptr i = 0; i < n_chunks_; i++) { 1096 Header *h = chunks_[i]; 1097 CHECK_EQ(h->chunk_idx, i); 1098 res += RoundUpMapSize(h->size); 1099 } 1100 return res; 1101 } 1102 1103 bool PointerIsMine(const void *p) { 1104 return GetBlockBegin(p) != 0; 1105 } 1106 1107 uptr GetActuallyAllocatedSize(void *p) { 1108 return RoundUpTo(GetHeader(p)->size, page_size_); 1109 } 1110 1111 // At least page_size_/2 metadata bytes is available. 1112 void *GetMetaData(const void *p) { 1113 // Too slow: CHECK_EQ(p, GetBlockBegin(p)); 1114 if (!IsAligned(reinterpret_cast<uptr>(p), page_size_)) { 1115 Printf("%s: bad pointer %p\n", SanitizerToolName, p); 1116 CHECK(IsAligned(reinterpret_cast<uptr>(p), page_size_)); 1117 } 1118 return GetHeader(p) + 1; 1119 } 1120 1121 void *GetBlockBegin(const void *ptr) { 1122 uptr p = reinterpret_cast<uptr>(ptr); 1123 SpinMutexLock l(&mutex_); 1124 uptr nearest_chunk = 0; 1125 // Cache-friendly linear search. 1126 for (uptr i = 0; i < n_chunks_; i++) { 1127 uptr ch = reinterpret_cast<uptr>(chunks_[i]); 1128 if (p < ch) continue; // p is at left to this chunk, skip it. 1129 if (p - ch < p - nearest_chunk) 1130 nearest_chunk = ch; 1131 } 1132 if (!nearest_chunk) 1133 return 0; 1134 Header *h = reinterpret_cast<Header *>(nearest_chunk); 1135 CHECK_GE(nearest_chunk, h->map_beg); 1136 CHECK_LT(nearest_chunk, h->map_beg + h->map_size); 1137 CHECK_LE(nearest_chunk, p); 1138 if (h->map_beg + h->map_size <= p) 1139 return 0; 1140 return GetUser(h); 1141 } 1142 1143 // This function does the same as GetBlockBegin, but is much faster. 1144 // Must be called with the allocator locked. 1145 void *GetBlockBeginFastLocked(void *ptr) { 1146 mutex_.CheckLocked(); 1147 uptr p = reinterpret_cast<uptr>(ptr); 1148 uptr n = n_chunks_; 1149 if (!n) return 0; 1150 if (!chunks_sorted_) { 1151 // Do one-time sort. chunks_sorted_ is reset in Allocate/Deallocate. 1152 SortArray(reinterpret_cast<uptr*>(chunks_), n); 1153 for (uptr i = 0; i < n; i++) 1154 chunks_[i]->chunk_idx = i; 1155 chunks_sorted_ = true; 1156 min_mmap_ = reinterpret_cast<uptr>(chunks_[0]); 1157 max_mmap_ = reinterpret_cast<uptr>(chunks_[n - 1]) + 1158 chunks_[n - 1]->map_size; 1159 } 1160 if (p < min_mmap_ || p >= max_mmap_) 1161 return 0; 1162 uptr beg = 0, end = n - 1; 1163 // This loop is a log(n) lower_bound. It does not check for the exact match 1164 // to avoid expensive cache-thrashing loads. 1165 while (end - beg >= 2) { 1166 uptr mid = (beg + end) / 2; // Invariant: mid >= beg + 1 1167 if (p < reinterpret_cast<uptr>(chunks_[mid])) 1168 end = mid - 1; // We are not interested in chunks_[mid]. 1169 else 1170 beg = mid; // chunks_[mid] may still be what we want. 1171 } 1172 1173 if (beg < end) { 1174 CHECK_EQ(beg + 1, end); 1175 // There are 2 chunks left, choose one. 1176 if (p >= reinterpret_cast<uptr>(chunks_[end])) 1177 beg = end; 1178 } 1179 1180 Header *h = chunks_[beg]; 1181 if (h->map_beg + h->map_size <= p || p < h->map_beg) 1182 return 0; 1183 return GetUser(h); 1184 } 1185 1186 void PrintStats() { 1187 Printf("Stats: LargeMmapAllocator: allocated %zd times, " 1188 "remains %zd (%zd K) max %zd M; by size logs: ", 1189 stats.n_allocs, stats.n_allocs - stats.n_frees, 1190 stats.currently_allocated >> 10, stats.max_allocated >> 20); 1191 for (uptr i = 0; i < ARRAY_SIZE(stats.by_size_log); i++) { 1192 uptr c = stats.by_size_log[i]; 1193 if (!c) continue; 1194 Printf("%zd:%zd; ", i, c); 1195 } 1196 Printf("\n"); 1197 } 1198 1199 // ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone 1200 // introspection API. 1201 void ForceLock() { 1202 mutex_.Lock(); 1203 } 1204 1205 void ForceUnlock() { 1206 mutex_.Unlock(); 1207 } 1208 1209 // Iterate over all existing chunks. 1210 // The allocator must be locked when calling this function. 1211 void ForEachChunk(ForEachChunkCallback callback, void *arg) { 1212 for (uptr i = 0; i < n_chunks_; i++) 1213 callback(reinterpret_cast<uptr>(GetUser(chunks_[i])), arg); 1214 } 1215 1216 private: 1217 static const int kMaxNumChunks = 1 << FIRST_32_SECOND_64(15, 18); 1218 struct Header { 1219 uptr map_beg; 1220 uptr map_size; 1221 uptr size; 1222 uptr chunk_idx; 1223 }; 1224 1225 Header *GetHeader(uptr p) { 1226 CHECK(IsAligned(p, page_size_)); 1227 return reinterpret_cast<Header*>(p - page_size_); 1228 } 1229 Header *GetHeader(const void *p) { 1230 return GetHeader(reinterpret_cast<uptr>(p)); 1231 } 1232 1233 void *GetUser(Header *h) { 1234 CHECK(IsAligned((uptr)h, page_size_)); 1235 return reinterpret_cast<void*>(reinterpret_cast<uptr>(h) + page_size_); 1236 } 1237 1238 uptr RoundUpMapSize(uptr size) { 1239 return RoundUpTo(size, page_size_) + page_size_; 1240 } 1241 1242 uptr page_size_; 1243 Header *chunks_[kMaxNumChunks]; 1244 uptr n_chunks_; 1245 uptr min_mmap_, max_mmap_; 1246 bool chunks_sorted_; 1247 struct Stats { 1248 uptr n_allocs, n_frees, currently_allocated, max_allocated, by_size_log[64]; 1249 } stats; 1250 atomic_uint8_t may_return_null_; 1251 SpinMutex mutex_; 1252 }; 1253 1254 // This class implements a complete memory allocator by using two 1255 // internal allocators: 1256 // PrimaryAllocator is efficient, but may not allocate some sizes (alignments). 1257 // When allocating 2^x bytes it should return 2^x aligned chunk. 1258 // PrimaryAllocator is used via a local AllocatorCache. 1259 // SecondaryAllocator can allocate anything, but is not efficient. 1260 template <class PrimaryAllocator, class AllocatorCache, 1261 class SecondaryAllocator> // NOLINT 1262 class CombinedAllocator { 1263 public: 1264 void InitCommon(bool may_return_null) { 1265 primary_.Init(); 1266 atomic_store(&may_return_null_, may_return_null, memory_order_relaxed); 1267 } 1268 1269 void InitLinkerInitialized(bool may_return_null) { 1270 secondary_.InitLinkerInitialized(may_return_null); 1271 stats_.InitLinkerInitialized(); 1272 InitCommon(may_return_null); 1273 } 1274 1275 void Init(bool may_return_null) { 1276 secondary_.Init(may_return_null); 1277 stats_.Init(); 1278 InitCommon(may_return_null); 1279 } 1280 1281 void *Allocate(AllocatorCache *cache, uptr size, uptr alignment, 1282 bool cleared = false, bool check_rss_limit = false) { 1283 // Returning 0 on malloc(0) may break a lot of code. 1284 if (size == 0) 1285 size = 1; 1286 if (size + alignment < size) 1287 return ReturnNullOrDie(); 1288 if (check_rss_limit && RssLimitIsExceeded()) 1289 return ReturnNullOrDie(); 1290 if (alignment > 8) 1291 size = RoundUpTo(size, alignment); 1292 void *res; 1293 bool from_primary = primary_.CanAllocate(size, alignment); 1294 if (from_primary) 1295 res = cache->Allocate(&primary_, primary_.ClassID(size)); 1296 else 1297 res = secondary_.Allocate(&stats_, size, alignment); 1298 if (alignment > 8) 1299 CHECK_EQ(reinterpret_cast<uptr>(res) & (alignment - 1), 0); 1300 if (cleared && res && from_primary) 1301 internal_bzero_aligned16(res, RoundUpTo(size, 16)); 1302 return res; 1303 } 1304 1305 bool MayReturnNull() const { 1306 return atomic_load(&may_return_null_, memory_order_acquire); 1307 } 1308 1309 void *ReturnNullOrDie() { 1310 if (MayReturnNull()) 1311 return 0; 1312 ReportAllocatorCannotReturnNull(); 1313 } 1314 1315 void SetMayReturnNull(bool may_return_null) { 1316 secondary_.SetMayReturnNull(may_return_null); 1317 atomic_store(&may_return_null_, may_return_null, memory_order_release); 1318 } 1319 1320 bool RssLimitIsExceeded() { 1321 return atomic_load(&rss_limit_is_exceeded_, memory_order_acquire); 1322 } 1323 1324 void SetRssLimitIsExceeded(bool rss_limit_is_exceeded) { 1325 atomic_store(&rss_limit_is_exceeded_, rss_limit_is_exceeded, 1326 memory_order_release); 1327 } 1328 1329 void Deallocate(AllocatorCache *cache, void *p) { 1330 if (!p) return; 1331 if (primary_.PointerIsMine(p)) 1332 cache->Deallocate(&primary_, primary_.GetSizeClass(p), p); 1333 else 1334 secondary_.Deallocate(&stats_, p); 1335 } 1336 1337 void *Reallocate(AllocatorCache *cache, void *p, uptr new_size, 1338 uptr alignment) { 1339 if (!p) 1340 return Allocate(cache, new_size, alignment); 1341 if (!new_size) { 1342 Deallocate(cache, p); 1343 return 0; 1344 } 1345 CHECK(PointerIsMine(p)); 1346 uptr old_size = GetActuallyAllocatedSize(p); 1347 uptr memcpy_size = Min(new_size, old_size); 1348 void *new_p = Allocate(cache, new_size, alignment); 1349 if (new_p) 1350 internal_memcpy(new_p, p, memcpy_size); 1351 Deallocate(cache, p); 1352 return new_p; 1353 } 1354 1355 bool PointerIsMine(void *p) { 1356 if (primary_.PointerIsMine(p)) 1357 return true; 1358 return secondary_.PointerIsMine(p); 1359 } 1360 1361 bool FromPrimary(void *p) { 1362 return primary_.PointerIsMine(p); 1363 } 1364 1365 void *GetMetaData(const void *p) { 1366 if (primary_.PointerIsMine(p)) 1367 return primary_.GetMetaData(p); 1368 return secondary_.GetMetaData(p); 1369 } 1370 1371 void *GetBlockBegin(const void *p) { 1372 if (primary_.PointerIsMine(p)) 1373 return primary_.GetBlockBegin(p); 1374 return secondary_.GetBlockBegin(p); 1375 } 1376 1377 // This function does the same as GetBlockBegin, but is much faster. 1378 // Must be called with the allocator locked. 1379 void *GetBlockBeginFastLocked(void *p) { 1380 if (primary_.PointerIsMine(p)) 1381 return primary_.GetBlockBegin(p); 1382 return secondary_.GetBlockBeginFastLocked(p); 1383 } 1384 1385 uptr GetActuallyAllocatedSize(void *p) { 1386 if (primary_.PointerIsMine(p)) 1387 return primary_.GetActuallyAllocatedSize(p); 1388 return secondary_.GetActuallyAllocatedSize(p); 1389 } 1390 1391 uptr TotalMemoryUsed() { 1392 return primary_.TotalMemoryUsed() + secondary_.TotalMemoryUsed(); 1393 } 1394 1395 void TestOnlyUnmap() { primary_.TestOnlyUnmap(); } 1396 1397 void InitCache(AllocatorCache *cache) { 1398 cache->Init(&stats_); 1399 } 1400 1401 void DestroyCache(AllocatorCache *cache) { 1402 cache->Destroy(&primary_, &stats_); 1403 } 1404 1405 void SwallowCache(AllocatorCache *cache) { 1406 cache->Drain(&primary_); 1407 } 1408 1409 void GetStats(AllocatorStatCounters s) const { 1410 stats_.Get(s); 1411 } 1412 1413 void PrintStats() { 1414 primary_.PrintStats(); 1415 secondary_.PrintStats(); 1416 } 1417 1418 // ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone 1419 // introspection API. 1420 void ForceLock() { 1421 primary_.ForceLock(); 1422 secondary_.ForceLock(); 1423 } 1424 1425 void ForceUnlock() { 1426 secondary_.ForceUnlock(); 1427 primary_.ForceUnlock(); 1428 } 1429 1430 // Iterate over all existing chunks. 1431 // The allocator must be locked when calling this function. 1432 void ForEachChunk(ForEachChunkCallback callback, void *arg) { 1433 primary_.ForEachChunk(callback, arg); 1434 secondary_.ForEachChunk(callback, arg); 1435 } 1436 1437 private: 1438 PrimaryAllocator primary_; 1439 SecondaryAllocator secondary_; 1440 AllocatorGlobalStats stats_; 1441 atomic_uint8_t may_return_null_; 1442 atomic_uint8_t rss_limit_is_exceeded_; 1443 }; 1444 1445 // Returns true if calloc(size, n) should return 0 due to overflow in size*n. 1446 bool CallocShouldReturnNullDueToOverflow(uptr size, uptr n); 1447 1448 } // namespace __sanitizer 1449 1450 #endif // SANITIZER_ALLOCATOR_H 1451 1452