1 //===-- sanitizer_allocator_primary64.h -------------------------*- C++ -*-===//
3 // This file is distributed under the University of Illinois Open Source
4 // License. See LICENSE.TXT for details.
6 //===----------------------------------------------------------------------===//
8 // Part of the Sanitizer Allocator.
10 //===----------------------------------------------------------------------===//
11 #ifndef SANITIZER_ALLOCATOR_H
12 #error This file must be included inside sanitizer_allocator.h
15 template<class SizeClassAllocator> struct SizeClassAllocator64LocalCache;
17 // SizeClassAllocator64 -- allocator for 64-bit address space.
18 // The template parameter Params is a class containing the actual parameters.
20 // Space: a portion of address space of kSpaceSize bytes starting at SpaceBeg.
21 // If kSpaceBeg is ~0 then SpaceBeg is chosen dynamically my mmap.
22 // Otherwise SpaceBeg=kSpaceBeg (fixed address).
23 // kSpaceSize is a power of two.
24 // At the beginning the entire space is mprotect-ed, then small parts of it
25 // are mapped on demand.
27 // Region: a part of Space dedicated to a single size class.
28 // There are kNumClasses Regions of equal size.
30 // UserChunk: a piece of memory returned to user.
31 // MetaChunk: kMetadataSize bytes of metadata associated with a UserChunk.
33 // FreeArray is an array free-d chunks (stored as 4-byte offsets)
35 // A Region looks like this:
36 // UserChunk1 ... UserChunkN <gap> MetaChunkN ... MetaChunk1 FreeArray
38 struct SizeClassAllocator64FlagMasks { // Bit masks.
40 kRandomShuffleChunks = 1,
44 template <class Params>
45 class SizeClassAllocator64 {
47 static const uptr kSpaceBeg = Params::kSpaceBeg;
48 static const uptr kSpaceSize = Params::kSpaceSize;
49 static const uptr kMetadataSize = Params::kMetadataSize;
50 typedef typename Params::SizeClassMap SizeClassMap;
51 typedef typename Params::MapUnmapCallback MapUnmapCallback;
53 static const bool kRandomShuffleChunks =
54 Params::kFlags & SizeClassAllocator64FlagMasks::kRandomShuffleChunks;
56 typedef SizeClassAllocator64<Params> ThisT;
57 typedef SizeClassAllocator64LocalCache<ThisT> AllocatorCache;
59 // When we know the size class (the region base) we can represent a pointer
60 // as a 4-byte integer (offset from the region start shifted right by 4).
61 typedef u32 CompactPtrT;
62 static const uptr kCompactPtrScale = 4;
63 CompactPtrT PointerToCompactPtr(uptr base, uptr ptr) {
64 return static_cast<CompactPtrT>((ptr - base) >> kCompactPtrScale);
66 uptr CompactPtrToPointer(uptr base, CompactPtrT ptr32) {
67 return base + (static_cast<uptr>(ptr32) << kCompactPtrScale);
70 void Init(s32 release_to_os_interval_ms) {
71 uptr TotalSpaceSize = kSpaceSize + AdditionalSize();
72 if (kUsingConstantSpaceBeg) {
73 CHECK_EQ(kSpaceBeg, reinterpret_cast<uptr>(
74 MmapFixedNoAccess(kSpaceBeg, TotalSpaceSize)));
77 reinterpret_cast<uptr>(MmapNoAccess(TotalSpaceSize));
78 CHECK_NE(NonConstSpaceBeg, ~(uptr)0);
80 SetReleaseToOSIntervalMs(release_to_os_interval_ms);
81 MapWithCallbackOrDie(SpaceEnd(), AdditionalSize());
84 s32 ReleaseToOSIntervalMs() const {
85 return atomic_load(&release_to_os_interval_ms_, memory_order_relaxed);
88 void SetReleaseToOSIntervalMs(s32 release_to_os_interval_ms) {
89 atomic_store(&release_to_os_interval_ms_, release_to_os_interval_ms,
90 memory_order_relaxed);
93 static bool CanAllocate(uptr size, uptr alignment) {
94 return size <= SizeClassMap::kMaxSize &&
95 alignment <= SizeClassMap::kMaxSize;
98 NOINLINE void ReturnToAllocator(AllocatorStats *stat, uptr class_id,
99 const CompactPtrT *chunks, uptr n_chunks) {
100 RegionInfo *region = GetRegionInfo(class_id);
101 uptr region_beg = GetRegionBeginBySizeClass(class_id);
102 CompactPtrT *free_array = GetFreeArray(region_beg);
104 BlockingMutexLock l(®ion->mutex);
105 uptr old_num_chunks = region->num_freed_chunks;
106 uptr new_num_freed_chunks = old_num_chunks + n_chunks;
107 EnsureFreeArraySpace(region, region_beg, new_num_freed_chunks);
108 // Failure to allocate free array space while releasing memory is non
110 if (UNLIKELY(!EnsureFreeArraySpace(region, region_beg,
111 new_num_freed_chunks))) {
112 Printf("OOM happened\n");
115 for (uptr i = 0; i < n_chunks; i++)
116 free_array[old_num_chunks + i] = chunks[i];
117 region->num_freed_chunks = new_num_freed_chunks;
118 region->stats.n_freed += n_chunks;
121 NOINLINE bool GetFromAllocator(AllocatorStats *stat, uptr class_id,
122 CompactPtrT *chunks, uptr n_chunks) {
123 RegionInfo *region = GetRegionInfo(class_id);
124 uptr region_beg = GetRegionBeginBySizeClass(class_id);
125 CompactPtrT *free_array = GetFreeArray(region_beg);
127 BlockingMutexLock l(®ion->mutex);
128 if (UNLIKELY(region->num_freed_chunks < n_chunks)) {
129 if (UNLIKELY(!PopulateFreeArray(stat, class_id, region,
130 n_chunks - region->num_freed_chunks)))
132 CHECK_GE(region->num_freed_chunks, n_chunks);
134 region->num_freed_chunks -= n_chunks;
135 uptr base_idx = region->num_freed_chunks;
136 for (uptr i = 0; i < n_chunks; i++)
137 chunks[i] = free_array[base_idx + i];
138 region->stats.n_allocated += n_chunks;
142 bool PointsIntoChunk(const void *p) {
143 CHECK(PointerIsMine(p));
144 uptr mem = reinterpret_cast<uptr>(p);
145 uptr class_id = GetSizeClass(p);
146 uptr size = SizeClassMap::Size(class_id);
147 uptr beg = kSpaceBeg + kRegionSize * class_id;
148 uptr n_chunks = kRegionSize / (size + kMetadataSize);
149 uptr gap_start = beg + n_chunks * size + 1;
150 return (beg <= mem) && (mem < gap_start);
153 bool PointerIsMine(const void *p) {
154 uptr P = reinterpret_cast<uptr>(p);
155 if (kUsingConstantSpaceBeg && (kSpaceBeg % kSpaceSize) == 0)
156 return P / kSpaceSize == kSpaceBeg / kSpaceSize;
157 return P >= SpaceBeg() && P < SpaceEnd();
160 uptr GetRegionBegin(const void *p) {
161 if (kUsingConstantSpaceBeg)
162 return reinterpret_cast<uptr>(p) & ~(kRegionSize - 1);
163 uptr space_beg = SpaceBeg();
164 return ((reinterpret_cast<uptr>(p) - space_beg) & ~(kRegionSize - 1)) +
168 uptr GetRegionBeginBySizeClass(uptr class_id) {
169 return SpaceBeg() + kRegionSize * class_id;
172 uptr GetSizeClass(const void *p) {
173 if (kUsingConstantSpaceBeg && (kSpaceBeg % kSpaceSize) == 0)
174 return ((reinterpret_cast<uptr>(p)) / kRegionSize) % kNumClassesRounded;
175 return ((reinterpret_cast<uptr>(p) - SpaceBeg()) / kRegionSize) %
179 void *GetBlockBegin(const void *p) {
180 uptr class_id = GetSizeClass(p);
181 uptr size = ClassIdToSize(class_id);
182 if (!size) return nullptr;
183 uptr chunk_idx = GetChunkIdx((uptr)p, size);
184 uptr reg_beg = GetRegionBegin(p);
185 uptr beg = chunk_idx * size;
186 uptr next_beg = beg + size;
187 if (class_id >= kNumClasses) return nullptr;
188 RegionInfo *region = GetRegionInfo(class_id);
189 if (region->mapped_user >= next_beg)
190 return reinterpret_cast<void*>(reg_beg + beg);
194 uptr GetActuallyAllocatedSize(void *p) {
195 CHECK(PointerIsMine(p));
196 return ClassIdToSize(GetSizeClass(p));
199 uptr ClassID(uptr size) { return SizeClassMap::ClassID(size); }
201 void *GetMetaData(const void *p) {
202 uptr class_id = GetSizeClass(p);
203 uptr size = ClassIdToSize(class_id);
204 uptr chunk_idx = GetChunkIdx(reinterpret_cast<uptr>(p), size);
205 uptr region_beg = GetRegionBeginBySizeClass(class_id);
206 return reinterpret_cast<void *>(GetMetadataEnd(region_beg) -
207 (1 + chunk_idx) * kMetadataSize);
210 uptr TotalMemoryUsed() {
212 for (uptr i = 0; i < kNumClasses; i++)
213 res += GetRegionInfo(i)->allocated_user;
218 void TestOnlyUnmap() {
219 UnmapWithCallbackOrDie(SpaceBeg(), kSpaceSize + AdditionalSize());
222 static void FillMemoryProfile(uptr start, uptr rss, bool file, uptr *stats,
224 for (uptr class_id = 0; class_id < stats_size; class_id++)
225 if (stats[class_id] == start)
226 stats[class_id] = rss;
229 void PrintStats(uptr class_id, uptr rss) {
230 RegionInfo *region = GetRegionInfo(class_id);
231 if (region->mapped_user == 0) return;
232 uptr in_use = region->stats.n_allocated - region->stats.n_freed;
233 uptr avail_chunks = region->allocated_user / ClassIdToSize(class_id);
235 "%s %02zd (%zd): mapped: %zdK allocs: %zd frees: %zd inuse: %zd "
236 "num_freed_chunks %zd"
237 " avail: %zd rss: %zdK releases: %zd\n",
238 region->exhausted ? "F" : " ", class_id, ClassIdToSize(class_id),
239 region->mapped_user >> 10, region->stats.n_allocated,
240 region->stats.n_freed, in_use, region->num_freed_chunks, avail_chunks,
241 rss >> 10, region->rtoi.num_releases);
245 uptr total_mapped = 0;
246 uptr n_allocated = 0;
248 for (uptr class_id = 1; class_id < kNumClasses; class_id++) {
249 RegionInfo *region = GetRegionInfo(class_id);
250 total_mapped += region->mapped_user;
251 n_allocated += region->stats.n_allocated;
252 n_freed += region->stats.n_freed;
254 Printf("Stats: SizeClassAllocator64: %zdM mapped in %zd allocations; "
256 total_mapped >> 20, n_allocated, n_allocated - n_freed);
257 uptr rss_stats[kNumClasses];
258 for (uptr class_id = 0; class_id < kNumClasses; class_id++)
259 rss_stats[class_id] = SpaceBeg() + kRegionSize * class_id;
260 GetMemoryProfile(FillMemoryProfile, rss_stats, kNumClasses);
261 for (uptr class_id = 1; class_id < kNumClasses; class_id++)
262 PrintStats(class_id, rss_stats[class_id]);
265 // ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone
266 // introspection API.
268 for (uptr i = 0; i < kNumClasses; i++) {
269 GetRegionInfo(i)->mutex.Lock();
274 for (int i = (int)kNumClasses - 1; i >= 0; i--) {
275 GetRegionInfo(i)->mutex.Unlock();
279 // Iterate over all existing chunks.
280 // The allocator must be locked when calling this function.
281 void ForEachChunk(ForEachChunkCallback callback, void *arg) {
282 for (uptr class_id = 1; class_id < kNumClasses; class_id++) {
283 RegionInfo *region = GetRegionInfo(class_id);
284 uptr chunk_size = ClassIdToSize(class_id);
285 uptr region_beg = SpaceBeg() + class_id * kRegionSize;
286 for (uptr chunk = region_beg;
287 chunk < region_beg + region->allocated_user;
288 chunk += chunk_size) {
289 // Too slow: CHECK_EQ((void *)chunk, GetBlockBegin((void *)chunk));
290 callback(chunk, arg);
295 static uptr ClassIdToSize(uptr class_id) {
296 return SizeClassMap::Size(class_id);
299 static uptr AdditionalSize() {
300 return RoundUpTo(sizeof(RegionInfo) * kNumClassesRounded,
301 GetPageSizeCached());
304 typedef SizeClassMap SizeClassMapT;
305 static const uptr kNumClasses = SizeClassMap::kNumClasses;
306 static const uptr kNumClassesRounded = SizeClassMap::kNumClassesRounded;
309 static const uptr kRegionSize = kSpaceSize / kNumClassesRounded;
310 // FreeArray is the array of free-d chunks (stored as 4-byte offsets).
311 // In the worst case it may reguire kRegionSize/SizeClassMap::kMinSize
312 // elements, but in reality this will not happen. For simplicity we
313 // dedicate 1/8 of the region's virtual space to FreeArray.
314 static const uptr kFreeArraySize = kRegionSize / 8;
316 static const bool kUsingConstantSpaceBeg = kSpaceBeg != ~(uptr)0;
317 uptr NonConstSpaceBeg;
318 uptr SpaceBeg() const {
319 return kUsingConstantSpaceBeg ? kSpaceBeg : NonConstSpaceBeg;
321 uptr SpaceEnd() const { return SpaceBeg() + kSpaceSize; }
322 // kRegionSize must be >= 2^32.
323 COMPILER_CHECK((kRegionSize) >= (1ULL << (SANITIZER_WORDSIZE / 2)));
324 // kRegionSize must be <= 2^36, see CompactPtrT.
325 COMPILER_CHECK((kRegionSize) <= (1ULL << (SANITIZER_WORDSIZE / 2 + 4)));
326 // Call mmap for user memory with at least this size.
327 static const uptr kUserMapSize = 1 << 16;
328 // Call mmap for metadata memory with at least this size.
329 static const uptr kMetaMapSize = 1 << 16;
330 // Call mmap for free array memory with at least this size.
331 static const uptr kFreeArrayMapSize = 1 << 16;
333 atomic_sint32_t release_to_os_interval_ms_;
340 struct ReleaseToOsInfo {
341 uptr n_freed_at_last_release;
343 u64 last_release_at_ns;
348 uptr num_freed_chunks; // Number of elements in the freearray.
349 uptr mapped_free_array; // Bytes mapped for freearray.
350 uptr allocated_user; // Bytes allocated for user memory.
351 uptr allocated_meta; // Bytes allocated for metadata.
352 uptr mapped_user; // Bytes mapped for user memory.
353 uptr mapped_meta; // Bytes mapped for metadata.
354 u32 rand_state; // Seed for random shuffle, used if kRandomShuffleChunks.
355 bool exhausted; // Whether region is out of space for new chunks.
357 ReleaseToOsInfo rtoi;
359 COMPILER_CHECK(sizeof(RegionInfo) >= kCacheLineSize);
361 u32 Rand(u32 *state) { // ANSI C linear congruential PRNG.
362 return (*state = *state * 1103515245 + 12345) >> 16;
365 u32 RandN(u32 *state, u32 n) { return Rand(state) % n; } // [0, n)
367 void RandomShuffle(u32 *a, u32 n, u32 *rand_state) {
369 for (u32 i = n - 1; i > 0; i--)
370 Swap(a[i], a[RandN(rand_state, i + 1)]);
373 RegionInfo *GetRegionInfo(uptr class_id) {
374 CHECK_LT(class_id, kNumClasses);
375 RegionInfo *regions =
376 reinterpret_cast<RegionInfo *>(SpaceBeg() + kSpaceSize);
377 return ®ions[class_id];
380 uptr GetMetadataEnd(uptr region_beg) {
381 return region_beg + kRegionSize - kFreeArraySize;
384 uptr GetChunkIdx(uptr chunk, uptr size) {
385 if (!kUsingConstantSpaceBeg)
388 uptr offset = chunk % kRegionSize;
389 // Here we divide by a non-constant. This is costly.
390 // size always fits into 32-bits. If the offset fits too, use 32-bit div.
391 if (offset >> (SANITIZER_WORDSIZE / 2))
392 return offset / size;
393 return (u32)offset / (u32)size;
396 CompactPtrT *GetFreeArray(uptr region_beg) {
397 return reinterpret_cast<CompactPtrT *>(region_beg + kRegionSize -
401 bool MapWithCallback(uptr beg, uptr size) {
402 uptr mapped = reinterpret_cast<uptr>(MmapFixedOrDieOnFatalError(beg, size));
405 CHECK_EQ(beg, mapped);
406 MapUnmapCallback().OnMap(beg, size);
410 void MapWithCallbackOrDie(uptr beg, uptr size) {
411 CHECK_EQ(beg, reinterpret_cast<uptr>(MmapFixedOrDie(beg, size)));
412 MapUnmapCallback().OnMap(beg, size);
415 void UnmapWithCallbackOrDie(uptr beg, uptr size) {
416 MapUnmapCallback().OnUnmap(beg, size);
417 UnmapOrDie(reinterpret_cast<void *>(beg), size);
420 bool EnsureFreeArraySpace(RegionInfo *region, uptr region_beg,
421 uptr num_freed_chunks) {
422 uptr needed_space = num_freed_chunks * sizeof(CompactPtrT);
423 if (region->mapped_free_array < needed_space) {
424 CHECK_LE(needed_space, kFreeArraySize);
425 uptr new_mapped_free_array = RoundUpTo(needed_space, kFreeArrayMapSize);
426 uptr current_map_end = reinterpret_cast<uptr>(GetFreeArray(region_beg)) +
427 region->mapped_free_array;
428 uptr new_map_size = new_mapped_free_array - region->mapped_free_array;
429 if (UNLIKELY(!MapWithCallback(current_map_end, new_map_size)))
431 region->mapped_free_array = new_mapped_free_array;
436 NOINLINE bool PopulateFreeArray(AllocatorStats *stat, uptr class_id,
437 RegionInfo *region, uptr requested_count) {
438 // region->mutex is held.
439 const uptr size = ClassIdToSize(class_id);
440 const uptr new_space_beg = region->allocated_user;
441 const uptr new_space_end = new_space_beg + requested_count * size;
442 const uptr region_beg = GetRegionBeginBySizeClass(class_id);
444 // Map more space for chunks, if necessary.
445 if (new_space_end > region->mapped_user) {
446 if (!kUsingConstantSpaceBeg && region->mapped_user == 0)
447 region->rand_state = static_cast<u32>(region_beg >> 12); // From ASLR.
448 // Do the mmap for the user memory.
449 uptr map_size = kUserMapSize;
450 while (new_space_end > region->mapped_user + map_size)
451 map_size += kUserMapSize;
452 CHECK_GE(region->mapped_user + map_size, new_space_end);
453 if (UNLIKELY(!MapWithCallback(region_beg + region->mapped_user,
456 stat->Add(AllocatorStatMapped, map_size);
457 region->mapped_user += map_size;
459 const uptr new_chunks_count = (region->mapped_user - new_space_beg) / size;
461 // Calculate the required space for metadata.
462 const uptr requested_allocated_meta =
463 region->allocated_meta + new_chunks_count * kMetadataSize;
464 uptr requested_mapped_meta = region->mapped_meta;
465 while (requested_allocated_meta > requested_mapped_meta)
466 requested_mapped_meta += kMetaMapSize;
467 // Check whether this size class is exhausted.
468 if (region->mapped_user + requested_mapped_meta >
469 kRegionSize - kFreeArraySize) {
470 if (!region->exhausted) {
471 region->exhausted = true;
472 Printf("%s: Out of memory. ", SanitizerToolName);
473 Printf("The process has exhausted %zuMB for size class %zu.\n",
474 kRegionSize >> 20, size);
478 // Map more space for metadata, if necessary.
479 if (requested_mapped_meta > region->mapped_meta) {
480 if (UNLIKELY(!MapWithCallback(
481 GetMetadataEnd(region_beg) - requested_mapped_meta,
482 requested_mapped_meta - region->mapped_meta)))
484 region->mapped_meta = requested_mapped_meta;
487 // If necessary, allocate more space for the free array and populate it with
488 // newly allocated chunks.
489 const uptr total_freed_chunks = region->num_freed_chunks + new_chunks_count;
490 if (UNLIKELY(!EnsureFreeArraySpace(region, region_beg, total_freed_chunks)))
492 CompactPtrT *free_array = GetFreeArray(region_beg);
493 for (uptr i = 0, chunk = new_space_beg; i < new_chunks_count;
495 free_array[total_freed_chunks - 1 - i] = PointerToCompactPtr(0, chunk);
496 if (kRandomShuffleChunks)
497 RandomShuffle(&free_array[region->num_freed_chunks], new_chunks_count,
498 ®ion->rand_state);
500 // All necessary memory is mapped and now it is safe to advance all
501 // 'allocated_*' counters.
502 region->num_freed_chunks += new_chunks_count;
503 region->allocated_user += new_chunks_count * size;
504 CHECK_LE(region->allocated_user, region->mapped_user);
505 region->allocated_meta = requested_allocated_meta;
506 CHECK_LE(region->allocated_meta, region->mapped_meta);
507 region->exhausted = false;
512 bool MaybeReleaseChunkRange(uptr region_beg, uptr chunk_size,
513 CompactPtrT first, CompactPtrT last) {
514 uptr beg_ptr = CompactPtrToPointer(region_beg, first);
515 uptr end_ptr = CompactPtrToPointer(region_beg, last) + chunk_size;
516 const uptr page_size = GetPageSizeCached();
517 CHECK_GE(end_ptr - beg_ptr, page_size);
518 beg_ptr = RoundUpTo(beg_ptr, page_size);
519 end_ptr = RoundDownTo(end_ptr, page_size);
520 if (end_ptr == beg_ptr) return false;
521 ReleaseMemoryToOS(beg_ptr, end_ptr - beg_ptr);
525 // Attempts to release some RAM back to OS. The region is expected to be
528 // * Sort the chunks.
529 // * Find ranges fully covered by free-d chunks
530 // * Release them to OS with madvise.
531 void MaybeReleaseToOS(uptr class_id) {
532 RegionInfo *region = GetRegionInfo(class_id);
533 const uptr chunk_size = ClassIdToSize(class_id);
534 const uptr page_size = GetPageSizeCached();
536 uptr n = region->num_freed_chunks;
537 if (n * chunk_size < page_size)
538 return; // No chance to release anything.
539 if ((region->n_freed - region->rtoi.n_freed_at_last_release) * chunk_size <
541 return; // Nothing new to release.
544 s32 interval_ms = ReleaseToOSIntervalMs();
548 u64 now_ns = NanoTime();
549 if (region->rtoi.last_release_at_ns + interval_ms * 1000000ULL > now_ns)
550 return; // Memory was returned recently.
551 region->rtoi.last_release_at_ns = now_ns;
553 uptr region_beg = GetRegionBeginBySizeClass(class_id);
554 CompactPtrT *free_array = GetFreeArray(region_beg);
555 SortArray(free_array, n);
557 const uptr scaled_chunk_size = chunk_size >> kCompactPtrScale;
558 const uptr kScaledGranularity = page_size >> kCompactPtrScale;
560 uptr range_beg = free_array[0];
561 uptr prev = free_array[0];
562 for (uptr i = 1; i < n; i++) {
563 uptr chunk = free_array[i];
564 CHECK_GT(chunk, prev);
565 if (chunk - prev != scaled_chunk_size) {
566 CHECK_GT(chunk - prev, scaled_chunk_size);
567 if (prev + scaled_chunk_size - range_beg >= kScaledGranularity) {
568 MaybeReleaseChunkRange(region_beg, chunk_size, range_beg, prev);
569 region->rtoi.n_freed_at_last_release = region->n_freed;
570 region->rtoi.num_releases++;