1 //===-- sanitizer_allocator_primary64.h -------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Part of the Sanitizer Allocator.
12 //===----------------------------------------------------------------------===//
13 #ifndef SANITIZER_ALLOCATOR_H
14 #error This file must be included inside sanitizer_allocator.h
17 template<class SizeClassAllocator> struct SizeClassAllocator64LocalCache;
19 // SizeClassAllocator64 -- allocator for 64-bit address space.
20 // The template parameter Params is a class containing the actual parameters.
22 // Space: a portion of address space of kSpaceSize bytes starting at SpaceBeg.
23 // If kSpaceBeg is ~0 then SpaceBeg is chosen dynamically my mmap.
24 // Otherwise SpaceBeg=kSpaceBeg (fixed address).
25 // kSpaceSize is a power of two.
26 // At the beginning the entire space is mprotect-ed, then small parts of it
27 // are mapped on demand.
29 // Region: a part of Space dedicated to a single size class.
30 // There are kNumClasses Regions of equal size.
32 // UserChunk: a piece of memory returned to user.
33 // MetaChunk: kMetadataSize bytes of metadata associated with a UserChunk.
35 // FreeArray is an array free-d chunks (stored as 4-byte offsets)
37 // A Region looks like this:
38 // UserChunk1 ... UserChunkN <gap> MetaChunkN ... MetaChunk1 FreeArray
40 struct SizeClassAllocator64FlagMasks { // Bit masks.
42 kRandomShuffleChunks = 1,
46 template <class Params>
47 class SizeClassAllocator64 {
49 static const uptr kSpaceBeg = Params::kSpaceBeg;
50 static const uptr kSpaceSize = Params::kSpaceSize;
51 static const uptr kMetadataSize = Params::kMetadataSize;
52 typedef typename Params::SizeClassMap SizeClassMap;
53 typedef typename Params::MapUnmapCallback MapUnmapCallback;
55 static const bool kRandomShuffleChunks =
56 Params::kFlags & SizeClassAllocator64FlagMasks::kRandomShuffleChunks;
58 typedef SizeClassAllocator64<Params> ThisT;
59 typedef SizeClassAllocator64LocalCache<ThisT> AllocatorCache;
61 // When we know the size class (the region base) we can represent a pointer
62 // as a 4-byte integer (offset from the region start shifted right by 4).
63 typedef u32 CompactPtrT;
64 static const uptr kCompactPtrScale = 4;
65 CompactPtrT PointerToCompactPtr(uptr base, uptr ptr) {
66 return static_cast<CompactPtrT>((ptr - base) >> kCompactPtrScale);
68 uptr CompactPtrToPointer(uptr base, CompactPtrT ptr32) {
69 return base + (static_cast<uptr>(ptr32) << kCompactPtrScale);
72 void Init(s32 release_to_os_interval_ms) {
73 uptr TotalSpaceSize = kSpaceSize + AdditionalSize();
74 if (kUsingConstantSpaceBeg) {
75 CHECK_EQ(kSpaceBeg, reinterpret_cast<uptr>(
76 MmapFixedNoAccess(kSpaceBeg, TotalSpaceSize)));
79 reinterpret_cast<uptr>(MmapNoAccess(TotalSpaceSize));
80 CHECK_NE(NonConstSpaceBeg, ~(uptr)0);
82 SetReleaseToOSIntervalMs(release_to_os_interval_ms);
83 MapWithCallbackOrDie(SpaceEnd(), AdditionalSize());
86 s32 ReleaseToOSIntervalMs() const {
87 return atomic_load(&release_to_os_interval_ms_, memory_order_relaxed);
90 void SetReleaseToOSIntervalMs(s32 release_to_os_interval_ms) {
91 atomic_store(&release_to_os_interval_ms_, release_to_os_interval_ms,
92 memory_order_relaxed);
95 static bool CanAllocate(uptr size, uptr alignment) {
96 return size <= SizeClassMap::kMaxSize &&
97 alignment <= SizeClassMap::kMaxSize;
100 NOINLINE void ReturnToAllocator(AllocatorStats *stat, uptr class_id,
101 const CompactPtrT *chunks, uptr n_chunks) {
102 RegionInfo *region = GetRegionInfo(class_id);
103 uptr region_beg = GetRegionBeginBySizeClass(class_id);
104 CompactPtrT *free_array = GetFreeArray(region_beg);
106 BlockingMutexLock l(®ion->mutex);
107 uptr old_num_chunks = region->num_freed_chunks;
108 uptr new_num_freed_chunks = old_num_chunks + n_chunks;
109 // Failure to allocate free array space while releasing memory is non
111 if (UNLIKELY(!EnsureFreeArraySpace(region, region_beg,
112 new_num_freed_chunks)))
113 DieOnFailure::OnOOM();
114 for (uptr i = 0; i < n_chunks; i++)
115 free_array[old_num_chunks + i] = chunks[i];
116 region->num_freed_chunks = new_num_freed_chunks;
117 region->stats.n_freed += n_chunks;
119 MaybeReleaseToOS(class_id);
122 NOINLINE bool GetFromAllocator(AllocatorStats *stat, uptr class_id,
123 CompactPtrT *chunks, uptr n_chunks) {
124 RegionInfo *region = GetRegionInfo(class_id);
125 uptr region_beg = GetRegionBeginBySizeClass(class_id);
126 CompactPtrT *free_array = GetFreeArray(region_beg);
128 BlockingMutexLock l(®ion->mutex);
129 if (UNLIKELY(region->num_freed_chunks < n_chunks)) {
130 if (UNLIKELY(!PopulateFreeArray(stat, class_id, region,
131 n_chunks - region->num_freed_chunks)))
133 CHECK_GE(region->num_freed_chunks, n_chunks);
135 region->num_freed_chunks -= n_chunks;
136 uptr base_idx = region->num_freed_chunks;
137 for (uptr i = 0; i < n_chunks; i++)
138 chunks[i] = free_array[base_idx + i];
139 region->stats.n_allocated += n_chunks;
143 bool PointerIsMine(const void *p) {
144 uptr P = reinterpret_cast<uptr>(p);
145 if (kUsingConstantSpaceBeg && (kSpaceBeg % kSpaceSize) == 0)
146 return P / kSpaceSize == kSpaceBeg / kSpaceSize;
147 return P >= SpaceBeg() && P < SpaceEnd();
150 uptr GetRegionBegin(const void *p) {
151 if (kUsingConstantSpaceBeg)
152 return reinterpret_cast<uptr>(p) & ~(kRegionSize - 1);
153 uptr space_beg = SpaceBeg();
154 return ((reinterpret_cast<uptr>(p) - space_beg) & ~(kRegionSize - 1)) +
158 uptr GetRegionBeginBySizeClass(uptr class_id) {
159 return SpaceBeg() + kRegionSize * class_id;
162 uptr GetSizeClass(const void *p) {
163 if (kUsingConstantSpaceBeg && (kSpaceBeg % kSpaceSize) == 0)
164 return ((reinterpret_cast<uptr>(p)) / kRegionSize) % kNumClassesRounded;
165 return ((reinterpret_cast<uptr>(p) - SpaceBeg()) / kRegionSize) %
169 void *GetBlockBegin(const void *p) {
170 uptr class_id = GetSizeClass(p);
171 uptr size = ClassIdToSize(class_id);
172 if (!size) return nullptr;
173 uptr chunk_idx = GetChunkIdx((uptr)p, size);
174 uptr reg_beg = GetRegionBegin(p);
175 uptr beg = chunk_idx * size;
176 uptr next_beg = beg + size;
177 if (class_id >= kNumClasses) return nullptr;
178 RegionInfo *region = GetRegionInfo(class_id);
179 if (region->mapped_user >= next_beg)
180 return reinterpret_cast<void*>(reg_beg + beg);
184 uptr GetActuallyAllocatedSize(void *p) {
185 CHECK(PointerIsMine(p));
186 return ClassIdToSize(GetSizeClass(p));
189 uptr ClassID(uptr size) { return SizeClassMap::ClassID(size); }
191 void *GetMetaData(const void *p) {
192 uptr class_id = GetSizeClass(p);
193 uptr size = ClassIdToSize(class_id);
194 uptr chunk_idx = GetChunkIdx(reinterpret_cast<uptr>(p), size);
195 uptr region_beg = GetRegionBeginBySizeClass(class_id);
196 return reinterpret_cast<void *>(GetMetadataEnd(region_beg) -
197 (1 + chunk_idx) * kMetadataSize);
200 uptr TotalMemoryUsed() {
202 for (uptr i = 0; i < kNumClasses; i++)
203 res += GetRegionInfo(i)->allocated_user;
208 void TestOnlyUnmap() {
209 UnmapWithCallbackOrDie(SpaceBeg(), kSpaceSize + AdditionalSize());
212 static void FillMemoryProfile(uptr start, uptr rss, bool file, uptr *stats,
214 for (uptr class_id = 0; class_id < stats_size; class_id++)
215 if (stats[class_id] == start)
216 stats[class_id] = rss;
219 void PrintStats(uptr class_id, uptr rss) {
220 RegionInfo *region = GetRegionInfo(class_id);
221 if (region->mapped_user == 0) return;
222 uptr in_use = region->stats.n_allocated - region->stats.n_freed;
223 uptr avail_chunks = region->allocated_user / ClassIdToSize(class_id);
225 "%s %02zd (%6zd): mapped: %6zdK allocs: %7zd frees: %7zd inuse: %6zd "
226 "num_freed_chunks %7zd avail: %6zd rss: %6zdK releases: %6zd\n",
227 region->exhausted ? "F" : " ", class_id, ClassIdToSize(class_id),
228 region->mapped_user >> 10, region->stats.n_allocated,
229 region->stats.n_freed, in_use, region->num_freed_chunks, avail_chunks,
230 rss >> 10, region->rtoi.num_releases);
234 uptr total_mapped = 0;
235 uptr n_allocated = 0;
237 for (uptr class_id = 1; class_id < kNumClasses; class_id++) {
238 RegionInfo *region = GetRegionInfo(class_id);
239 total_mapped += region->mapped_user;
240 n_allocated += region->stats.n_allocated;
241 n_freed += region->stats.n_freed;
243 Printf("Stats: SizeClassAllocator64: %zdM mapped in %zd allocations; "
245 total_mapped >> 20, n_allocated, n_allocated - n_freed);
246 uptr rss_stats[kNumClasses];
247 for (uptr class_id = 0; class_id < kNumClasses; class_id++)
248 rss_stats[class_id] = SpaceBeg() + kRegionSize * class_id;
249 GetMemoryProfile(FillMemoryProfile, rss_stats, kNumClasses);
250 for (uptr class_id = 1; class_id < kNumClasses; class_id++)
251 PrintStats(class_id, rss_stats[class_id]);
254 // ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone
255 // introspection API.
257 for (uptr i = 0; i < kNumClasses; i++) {
258 GetRegionInfo(i)->mutex.Lock();
263 for (int i = (int)kNumClasses - 1; i >= 0; i--) {
264 GetRegionInfo(i)->mutex.Unlock();
268 // Iterate over all existing chunks.
269 // The allocator must be locked when calling this function.
270 void ForEachChunk(ForEachChunkCallback callback, void *arg) {
271 for (uptr class_id = 1; class_id < kNumClasses; class_id++) {
272 RegionInfo *region = GetRegionInfo(class_id);
273 uptr chunk_size = ClassIdToSize(class_id);
274 uptr region_beg = SpaceBeg() + class_id * kRegionSize;
275 for (uptr chunk = region_beg;
276 chunk < region_beg + region->allocated_user;
277 chunk += chunk_size) {
278 // Too slow: CHECK_EQ((void *)chunk, GetBlockBegin((void *)chunk));
279 callback(chunk, arg);
284 static uptr ClassIdToSize(uptr class_id) {
285 return SizeClassMap::Size(class_id);
288 static uptr AdditionalSize() {
289 return RoundUpTo(sizeof(RegionInfo) * kNumClassesRounded,
290 GetPageSizeCached());
293 typedef SizeClassMap SizeClassMapT;
294 static const uptr kNumClasses = SizeClassMap::kNumClasses;
295 static const uptr kNumClassesRounded = SizeClassMap::kNumClassesRounded;
298 static const uptr kRegionSize = kSpaceSize / kNumClassesRounded;
299 // FreeArray is the array of free-d chunks (stored as 4-byte offsets).
300 // In the worst case it may reguire kRegionSize/SizeClassMap::kMinSize
301 // elements, but in reality this will not happen. For simplicity we
302 // dedicate 1/8 of the region's virtual space to FreeArray.
303 static const uptr kFreeArraySize = kRegionSize / 8;
305 static const bool kUsingConstantSpaceBeg = kSpaceBeg != ~(uptr)0;
306 uptr NonConstSpaceBeg;
307 uptr SpaceBeg() const {
308 return kUsingConstantSpaceBeg ? kSpaceBeg : NonConstSpaceBeg;
310 uptr SpaceEnd() const { return SpaceBeg() + kSpaceSize; }
311 // kRegionSize must be >= 2^32.
312 COMPILER_CHECK((kRegionSize) >= (1ULL << (SANITIZER_WORDSIZE / 2)));
313 // kRegionSize must be <= 2^36, see CompactPtrT.
314 COMPILER_CHECK((kRegionSize) <= (1ULL << (SANITIZER_WORDSIZE / 2 + 4)));
315 // Call mmap for user memory with at least this size.
316 static const uptr kUserMapSize = 1 << 16;
317 // Call mmap for metadata memory with at least this size.
318 static const uptr kMetaMapSize = 1 << 16;
319 // Call mmap for free array memory with at least this size.
320 static const uptr kFreeArrayMapSize = 1 << 16;
322 atomic_sint32_t release_to_os_interval_ms_;
329 struct ReleaseToOsInfo {
330 uptr n_freed_at_last_release;
332 u64 last_release_at_ns;
337 uptr num_freed_chunks; // Number of elements in the freearray.
338 uptr mapped_free_array; // Bytes mapped for freearray.
339 uptr allocated_user; // Bytes allocated for user memory.
340 uptr allocated_meta; // Bytes allocated for metadata.
341 uptr mapped_user; // Bytes mapped for user memory.
342 uptr mapped_meta; // Bytes mapped for metadata.
343 u32 rand_state; // Seed for random shuffle, used if kRandomShuffleChunks.
344 bool exhausted; // Whether region is out of space for new chunks.
346 ReleaseToOsInfo rtoi;
348 COMPILER_CHECK(sizeof(RegionInfo) >= kCacheLineSize);
350 u32 Rand(u32 *state) { // ANSI C linear congruential PRNG.
351 return (*state = *state * 1103515245 + 12345) >> 16;
354 u32 RandN(u32 *state, u32 n) { return Rand(state) % n; } // [0, n)
356 void RandomShuffle(u32 *a, u32 n, u32 *rand_state) {
358 for (u32 i = n - 1; i > 0; i--)
359 Swap(a[i], a[RandN(rand_state, i + 1)]);
362 RegionInfo *GetRegionInfo(uptr class_id) {
363 CHECK_LT(class_id, kNumClasses);
364 RegionInfo *regions =
365 reinterpret_cast<RegionInfo *>(SpaceBeg() + kSpaceSize);
366 return ®ions[class_id];
369 uptr GetMetadataEnd(uptr region_beg) {
370 return region_beg + kRegionSize - kFreeArraySize;
373 uptr GetChunkIdx(uptr chunk, uptr size) {
374 if (!kUsingConstantSpaceBeg)
377 uptr offset = chunk % kRegionSize;
378 // Here we divide by a non-constant. This is costly.
379 // size always fits into 32-bits. If the offset fits too, use 32-bit div.
380 if (offset >> (SANITIZER_WORDSIZE / 2))
381 return offset / size;
382 return (u32)offset / (u32)size;
385 CompactPtrT *GetFreeArray(uptr region_beg) {
386 return reinterpret_cast<CompactPtrT *>(region_beg + kRegionSize -
390 bool MapWithCallback(uptr beg, uptr size) {
391 uptr mapped = reinterpret_cast<uptr>(MmapFixedOrDieOnFatalError(beg, size));
392 if (UNLIKELY(!mapped))
394 CHECK_EQ(beg, mapped);
395 MapUnmapCallback().OnMap(beg, size);
399 void MapWithCallbackOrDie(uptr beg, uptr size) {
400 CHECK_EQ(beg, reinterpret_cast<uptr>(MmapFixedOrDie(beg, size)));
401 MapUnmapCallback().OnMap(beg, size);
404 void UnmapWithCallbackOrDie(uptr beg, uptr size) {
405 MapUnmapCallback().OnUnmap(beg, size);
406 UnmapOrDie(reinterpret_cast<void *>(beg), size);
409 bool EnsureFreeArraySpace(RegionInfo *region, uptr region_beg,
410 uptr num_freed_chunks) {
411 uptr needed_space = num_freed_chunks * sizeof(CompactPtrT);
412 if (region->mapped_free_array < needed_space) {
413 CHECK_LE(needed_space, kFreeArraySize);
414 uptr new_mapped_free_array = RoundUpTo(needed_space, kFreeArrayMapSize);
415 uptr current_map_end = reinterpret_cast<uptr>(GetFreeArray(region_beg)) +
416 region->mapped_free_array;
417 uptr new_map_size = new_mapped_free_array - region->mapped_free_array;
418 if (UNLIKELY(!MapWithCallback(current_map_end, new_map_size)))
420 region->mapped_free_array = new_mapped_free_array;
425 NOINLINE bool PopulateFreeArray(AllocatorStats *stat, uptr class_id,
426 RegionInfo *region, uptr requested_count) {
427 // region->mutex is held.
428 const uptr size = ClassIdToSize(class_id);
429 const uptr new_space_beg = region->allocated_user;
430 const uptr new_space_end = new_space_beg + requested_count * size;
431 const uptr region_beg = GetRegionBeginBySizeClass(class_id);
433 // Map more space for chunks, if necessary.
434 if (new_space_end > region->mapped_user) {
435 if (!kUsingConstantSpaceBeg && region->mapped_user == 0)
436 region->rand_state = static_cast<u32>(region_beg >> 12); // From ASLR.
437 // Do the mmap for the user memory.
438 uptr map_size = kUserMapSize;
439 while (new_space_end > region->mapped_user + map_size)
440 map_size += kUserMapSize;
441 CHECK_GE(region->mapped_user + map_size, new_space_end);
442 if (UNLIKELY(!MapWithCallback(region_beg + region->mapped_user,
445 stat->Add(AllocatorStatMapped, map_size);
446 region->mapped_user += map_size;
448 const uptr new_chunks_count = (region->mapped_user - new_space_beg) / size;
450 // Calculate the required space for metadata.
451 const uptr requested_allocated_meta =
452 region->allocated_meta + new_chunks_count * kMetadataSize;
453 uptr requested_mapped_meta = region->mapped_meta;
454 while (requested_allocated_meta > requested_mapped_meta)
455 requested_mapped_meta += kMetaMapSize;
456 // Check whether this size class is exhausted.
457 if (region->mapped_user + requested_mapped_meta >
458 kRegionSize - kFreeArraySize) {
459 if (!region->exhausted) {
460 region->exhausted = true;
461 Printf("%s: Out of memory. ", SanitizerToolName);
462 Printf("The process has exhausted %zuMB for size class %zu.\n",
463 kRegionSize >> 20, size);
467 // Map more space for metadata, if necessary.
468 if (requested_mapped_meta > region->mapped_meta) {
469 if (UNLIKELY(!MapWithCallback(
470 GetMetadataEnd(region_beg) - requested_mapped_meta,
471 requested_mapped_meta - region->mapped_meta)))
473 region->mapped_meta = requested_mapped_meta;
476 // If necessary, allocate more space for the free array and populate it with
477 // newly allocated chunks.
478 const uptr total_freed_chunks = region->num_freed_chunks + new_chunks_count;
479 if (UNLIKELY(!EnsureFreeArraySpace(region, region_beg, total_freed_chunks)))
481 CompactPtrT *free_array = GetFreeArray(region_beg);
482 for (uptr i = 0, chunk = new_space_beg; i < new_chunks_count;
484 free_array[total_freed_chunks - 1 - i] = PointerToCompactPtr(0, chunk);
485 if (kRandomShuffleChunks)
486 RandomShuffle(&free_array[region->num_freed_chunks], new_chunks_count,
487 ®ion->rand_state);
489 // All necessary memory is mapped and now it is safe to advance all
490 // 'allocated_*' counters.
491 region->num_freed_chunks += new_chunks_count;
492 region->allocated_user += new_chunks_count * size;
493 CHECK_LE(region->allocated_user, region->mapped_user);
494 region->allocated_meta = requested_allocated_meta;
495 CHECK_LE(region->allocated_meta, region->mapped_meta);
496 region->exhausted = false;
501 void MaybeReleaseChunkRange(uptr region_beg, uptr chunk_size,
502 CompactPtrT first, CompactPtrT last) {
503 uptr beg_ptr = CompactPtrToPointer(region_beg, first);
504 uptr end_ptr = CompactPtrToPointer(region_beg, last) + chunk_size;
505 ReleaseMemoryPagesToOS(beg_ptr, end_ptr);
508 // Attempts to release some RAM back to OS. The region is expected to be
511 // * Sort the chunks.
512 // * Find ranges fully covered by free-d chunks
513 // * Release them to OS with madvise.
514 void MaybeReleaseToOS(uptr class_id) {
515 RegionInfo *region = GetRegionInfo(class_id);
516 const uptr chunk_size = ClassIdToSize(class_id);
517 const uptr page_size = GetPageSizeCached();
519 uptr n = region->num_freed_chunks;
520 if (n * chunk_size < page_size)
521 return; // No chance to release anything.
522 if ((region->stats.n_freed -
523 region->rtoi.n_freed_at_last_release) * chunk_size < page_size) {
524 return; // Nothing new to release.
527 s32 interval_ms = ReleaseToOSIntervalMs();
531 u64 now_ns = NanoTime();
532 if (region->rtoi.last_release_at_ns + interval_ms * 1000000ULL > now_ns)
533 return; // Memory was returned recently.
534 region->rtoi.last_release_at_ns = now_ns;
536 uptr region_beg = GetRegionBeginBySizeClass(class_id);
537 CompactPtrT *free_array = GetFreeArray(region_beg);
538 SortArray(free_array, n);
540 const uptr scaled_chunk_size = chunk_size >> kCompactPtrScale;
541 const uptr kScaledGranularity = page_size >> kCompactPtrScale;
543 uptr range_beg = free_array[0];
544 uptr prev = free_array[0];
545 for (uptr i = 1; i < n; i++) {
546 uptr chunk = free_array[i];
547 CHECK_GT(chunk, prev);
548 if (chunk - prev != scaled_chunk_size) {
549 CHECK_GT(chunk - prev, scaled_chunk_size);
550 if (prev + scaled_chunk_size - range_beg >= kScaledGranularity) {
551 MaybeReleaseChunkRange(region_beg, chunk_size, range_beg, prev);
552 region->rtoi.n_freed_at_last_release = region->stats.n_freed;
553 region->rtoi.num_releases++;