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) const {
66 return static_cast<CompactPtrT>((ptr - base) >> kCompactPtrScale);
68 uptr CompactPtrToPointer(uptr base, CompactPtrT ptr32) const {
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, address_range.Init(TotalSpaceSize, AllocatorName(),
78 NonConstSpaceBeg = address_range.Init(TotalSpaceSize, AllocatorName());
79 CHECK_NE(NonConstSpaceBeg, ~(uptr)0);
81 SetReleaseToOSIntervalMs(release_to_os_interval_ms);
82 MapWithCallbackOrDie(SpaceEnd(), AdditionalSize());
85 s32 ReleaseToOSIntervalMs() const {
86 return atomic_load(&release_to_os_interval_ms_, memory_order_relaxed);
89 void SetReleaseToOSIntervalMs(s32 release_to_os_interval_ms) {
90 atomic_store(&release_to_os_interval_ms_, release_to_os_interval_ms,
91 memory_order_relaxed);
94 void ForceReleaseToOS() {
95 for (uptr class_id = 1; class_id < kNumClasses; class_id++) {
96 BlockingMutexLock l(&GetRegionInfo(class_id)->mutex);
97 MaybeReleaseToOS(class_id, true /*force*/);
101 static bool CanAllocate(uptr size, uptr alignment) {
102 return size <= SizeClassMap::kMaxSize &&
103 alignment <= SizeClassMap::kMaxSize;
106 NOINLINE void ReturnToAllocator(AllocatorStats *stat, uptr class_id,
107 const CompactPtrT *chunks, uptr n_chunks) {
108 RegionInfo *region = GetRegionInfo(class_id);
109 uptr region_beg = GetRegionBeginBySizeClass(class_id);
110 CompactPtrT *free_array = GetFreeArray(region_beg);
112 BlockingMutexLock l(®ion->mutex);
113 uptr old_num_chunks = region->num_freed_chunks;
114 uptr new_num_freed_chunks = old_num_chunks + n_chunks;
115 // Failure to allocate free array space while releasing memory is non
117 if (UNLIKELY(!EnsureFreeArraySpace(region, region_beg,
118 new_num_freed_chunks)))
119 DieOnFailure::OnOOM();
120 for (uptr i = 0; i < n_chunks; i++)
121 free_array[old_num_chunks + i] = chunks[i];
122 region->num_freed_chunks = new_num_freed_chunks;
123 region->stats.n_freed += n_chunks;
125 MaybeReleaseToOS(class_id, false /*force*/);
128 NOINLINE bool GetFromAllocator(AllocatorStats *stat, uptr class_id,
129 CompactPtrT *chunks, uptr n_chunks) {
130 RegionInfo *region = GetRegionInfo(class_id);
131 uptr region_beg = GetRegionBeginBySizeClass(class_id);
132 CompactPtrT *free_array = GetFreeArray(region_beg);
134 BlockingMutexLock l(®ion->mutex);
135 if (UNLIKELY(region->num_freed_chunks < n_chunks)) {
136 if (UNLIKELY(!PopulateFreeArray(stat, class_id, region,
137 n_chunks - region->num_freed_chunks)))
139 CHECK_GE(region->num_freed_chunks, n_chunks);
141 region->num_freed_chunks -= n_chunks;
142 uptr base_idx = region->num_freed_chunks;
143 for (uptr i = 0; i < n_chunks; i++)
144 chunks[i] = free_array[base_idx + i];
145 region->stats.n_allocated += n_chunks;
149 bool PointerIsMine(const void *p) {
150 uptr P = reinterpret_cast<uptr>(p);
151 if (kUsingConstantSpaceBeg && (kSpaceBeg % kSpaceSize) == 0)
152 return P / kSpaceSize == kSpaceBeg / kSpaceSize;
153 return P >= SpaceBeg() && P < SpaceEnd();
156 uptr GetRegionBegin(const void *p) {
157 if (kUsingConstantSpaceBeg)
158 return reinterpret_cast<uptr>(p) & ~(kRegionSize - 1);
159 uptr space_beg = SpaceBeg();
160 return ((reinterpret_cast<uptr>(p) - space_beg) & ~(kRegionSize - 1)) +
164 uptr GetRegionBeginBySizeClass(uptr class_id) const {
165 return SpaceBeg() + kRegionSize * class_id;
168 uptr GetSizeClass(const void *p) {
169 if (kUsingConstantSpaceBeg && (kSpaceBeg % kSpaceSize) == 0)
170 return ((reinterpret_cast<uptr>(p)) / kRegionSize) % kNumClassesRounded;
171 return ((reinterpret_cast<uptr>(p) - SpaceBeg()) / kRegionSize) %
175 void *GetBlockBegin(const void *p) {
176 uptr class_id = GetSizeClass(p);
177 uptr size = ClassIdToSize(class_id);
178 if (!size) return nullptr;
179 uptr chunk_idx = GetChunkIdx((uptr)p, size);
180 uptr reg_beg = GetRegionBegin(p);
181 uptr beg = chunk_idx * size;
182 uptr next_beg = beg + size;
183 if (class_id >= kNumClasses) return nullptr;
184 RegionInfo *region = GetRegionInfo(class_id);
185 if (region->mapped_user >= next_beg)
186 return reinterpret_cast<void*>(reg_beg + beg);
190 uptr GetActuallyAllocatedSize(void *p) {
191 CHECK(PointerIsMine(p));
192 return ClassIdToSize(GetSizeClass(p));
195 uptr ClassID(uptr size) { return SizeClassMap::ClassID(size); }
197 void *GetMetaData(const void *p) {
198 uptr class_id = GetSizeClass(p);
199 uptr size = ClassIdToSize(class_id);
200 uptr chunk_idx = GetChunkIdx(reinterpret_cast<uptr>(p), size);
201 uptr region_beg = GetRegionBeginBySizeClass(class_id);
202 return reinterpret_cast<void *>(GetMetadataEnd(region_beg) -
203 (1 + chunk_idx) * kMetadataSize);
206 uptr TotalMemoryUsed() {
208 for (uptr i = 0; i < kNumClasses; i++)
209 res += GetRegionInfo(i)->allocated_user;
214 void TestOnlyUnmap() {
215 UnmapWithCallbackOrDie(SpaceBeg(), kSpaceSize + AdditionalSize());
218 static void FillMemoryProfile(uptr start, uptr rss, bool file, uptr *stats,
220 for (uptr class_id = 0; class_id < stats_size; class_id++)
221 if (stats[class_id] == start)
222 stats[class_id] = rss;
225 void PrintStats(uptr class_id, uptr rss) {
226 RegionInfo *region = GetRegionInfo(class_id);
227 if (region->mapped_user == 0) return;
228 uptr in_use = region->stats.n_allocated - region->stats.n_freed;
229 uptr avail_chunks = region->allocated_user / ClassIdToSize(class_id);
231 "%s %02zd (%6zd): mapped: %6zdK allocs: %7zd frees: %7zd inuse: %6zd "
232 "num_freed_chunks %7zd avail: %6zd rss: %6zdK releases: %6zd "
233 "last released: %6zdK region: 0x%zx\n",
234 region->exhausted ? "F" : " ", class_id, ClassIdToSize(class_id),
235 region->mapped_user >> 10, region->stats.n_allocated,
236 region->stats.n_freed, in_use, region->num_freed_chunks, avail_chunks,
237 rss >> 10, region->rtoi.num_releases,
238 region->rtoi.last_released_bytes >> 10,
239 SpaceBeg() + kRegionSize * class_id);
243 uptr rss_stats[kNumClasses];
244 for (uptr class_id = 0; class_id < kNumClasses; class_id++)
245 rss_stats[class_id] = SpaceBeg() + kRegionSize * class_id;
246 GetMemoryProfile(FillMemoryProfile, rss_stats, kNumClasses);
248 uptr total_mapped = 0;
250 uptr n_allocated = 0;
252 for (uptr class_id = 1; class_id < kNumClasses; class_id++) {
253 RegionInfo *region = GetRegionInfo(class_id);
254 if (region->mapped_user != 0) {
255 total_mapped += region->mapped_user;
256 total_rss += rss_stats[class_id];
258 n_allocated += region->stats.n_allocated;
259 n_freed += region->stats.n_freed;
262 Printf("Stats: SizeClassAllocator64: %zdM mapped (%zdM rss) in "
263 "%zd allocations; remains %zd\n", total_mapped >> 20,
264 total_rss >> 20, n_allocated, n_allocated - n_freed);
265 for (uptr class_id = 1; class_id < kNumClasses; class_id++)
266 PrintStats(class_id, rss_stats[class_id]);
269 // ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone
270 // introspection API.
272 for (uptr i = 0; i < kNumClasses; i++) {
273 GetRegionInfo(i)->mutex.Lock();
278 for (int i = (int)kNumClasses - 1; i >= 0; i--) {
279 GetRegionInfo(i)->mutex.Unlock();
283 // Iterate over all existing chunks.
284 // The allocator must be locked when calling this function.
285 void ForEachChunk(ForEachChunkCallback callback, void *arg) {
286 for (uptr class_id = 1; class_id < kNumClasses; class_id++) {
287 RegionInfo *region = GetRegionInfo(class_id);
288 uptr chunk_size = ClassIdToSize(class_id);
289 uptr region_beg = SpaceBeg() + class_id * kRegionSize;
290 for (uptr chunk = region_beg;
291 chunk < region_beg + region->allocated_user;
292 chunk += chunk_size) {
293 // Too slow: CHECK_EQ((void *)chunk, GetBlockBegin((void *)chunk));
294 callback(chunk, arg);
299 static uptr ClassIdToSize(uptr class_id) {
300 return SizeClassMap::Size(class_id);
303 static uptr AdditionalSize() {
304 return RoundUpTo(sizeof(RegionInfo) * kNumClassesRounded,
305 GetPageSizeCached());
308 typedef SizeClassMap SizeClassMapT;
309 static const uptr kNumClasses = SizeClassMap::kNumClasses;
310 static const uptr kNumClassesRounded = SizeClassMap::kNumClassesRounded;
312 // A packed array of counters. Each counter occupies 2^n bits, enough to store
313 // counter's max_value. Ctor will try to allocate the required buffer via
314 // mapper->MapPackedCounterArrayBuffer and the caller is expected to check
315 // whether the initialization was successful by checking IsAllocated() result.
316 // For the performance sake, none of the accessors check the validity of the
317 // arguments, it is assumed that index is always in [0, n) range and the value
318 // is not incremented past max_value.
319 template<class MemoryMapperT>
320 class PackedCounterArray {
322 PackedCounterArray(u64 num_counters, u64 max_value, MemoryMapperT *mapper)
323 : n(num_counters), memory_mapper(mapper) {
324 CHECK_GT(num_counters, 0);
325 CHECK_GT(max_value, 0);
326 constexpr u64 kMaxCounterBits = sizeof(*buffer) * 8ULL;
327 // Rounding counter storage size up to the power of two allows for using
328 // bit shifts calculating particular counter's index and offset.
329 uptr counter_size_bits =
330 RoundUpToPowerOfTwo(MostSignificantSetBitIndex(max_value) + 1);
331 CHECK_LE(counter_size_bits, kMaxCounterBits);
332 counter_size_bits_log = Log2(counter_size_bits);
333 counter_mask = ~0ULL >> (kMaxCounterBits - counter_size_bits);
335 uptr packing_ratio = kMaxCounterBits >> counter_size_bits_log;
336 CHECK_GT(packing_ratio, 0);
337 packing_ratio_log = Log2(packing_ratio);
338 bit_offset_mask = packing_ratio - 1;
341 (RoundUpTo(n, 1ULL << packing_ratio_log) >> packing_ratio_log) *
343 buffer = reinterpret_cast<u64*>(
344 memory_mapper->MapPackedCounterArrayBuffer(buffer_size));
346 ~PackedCounterArray() {
348 memory_mapper->UnmapPackedCounterArrayBuffer(
349 reinterpret_cast<uptr>(buffer), buffer_size);
353 bool IsAllocated() const {
357 u64 GetCount() const {
361 uptr Get(uptr i) const {
363 uptr index = i >> packing_ratio_log;
364 uptr bit_offset = (i & bit_offset_mask) << counter_size_bits_log;
365 return (buffer[index] >> bit_offset) & counter_mask;
368 void Inc(uptr i) const {
369 DCHECK_LT(Get(i), counter_mask);
370 uptr index = i >> packing_ratio_log;
371 uptr bit_offset = (i & bit_offset_mask) << counter_size_bits_log;
372 buffer[index] += 1ULL << bit_offset;
375 void IncRange(uptr from, uptr to) const {
377 for (uptr i = from; i <= to; i++)
383 u64 counter_size_bits_log;
385 u64 packing_ratio_log;
388 MemoryMapperT* const memory_mapper;
393 template<class MemoryMapperT>
394 class FreePagesRangeTracker {
396 explicit FreePagesRangeTracker(MemoryMapperT* mapper)
397 : memory_mapper(mapper),
398 page_size_scaled_log(Log2(GetPageSizeCached() >> kCompactPtrScale)),
399 in_the_range(false), current_page(0), current_range_start_page(0) {}
401 void NextPage(bool freed) {
404 current_range_start_page = current_page;
418 void CloseOpenedRange() {
420 memory_mapper->ReleasePageRangeToOS(
421 current_range_start_page << page_size_scaled_log,
422 current_page << page_size_scaled_log);
423 in_the_range = false;
427 MemoryMapperT* const memory_mapper;
428 const uptr page_size_scaled_log;
431 uptr current_range_start_page;
434 // Iterates over the free_array to identify memory pages containing freed
435 // chunks only and returns these pages back to OS.
436 // allocated_pages_count is the total number of pages allocated for the
438 template<class MemoryMapperT>
439 static void ReleaseFreeMemoryToOS(CompactPtrT *free_array,
440 uptr free_array_count, uptr chunk_size,
441 uptr allocated_pages_count,
442 MemoryMapperT *memory_mapper) {
443 const uptr page_size = GetPageSizeCached();
445 // Figure out the number of chunks per page and whether we can take a fast
446 // path (the number of chunks per page is the same for all pages).
447 uptr full_pages_chunk_count_max;
448 bool same_chunk_count_per_page;
449 if (chunk_size <= page_size && page_size % chunk_size == 0) {
450 // Same number of chunks per page, no cross overs.
451 full_pages_chunk_count_max = page_size / chunk_size;
452 same_chunk_count_per_page = true;
453 } else if (chunk_size <= page_size && page_size % chunk_size != 0 &&
454 chunk_size % (page_size % chunk_size) == 0) {
455 // Some chunks are crossing page boundaries, which means that the page
456 // contains one or two partial chunks, but all pages contain the same
458 full_pages_chunk_count_max = page_size / chunk_size + 1;
459 same_chunk_count_per_page = true;
460 } else if (chunk_size <= page_size) {
461 // Some chunks are crossing page boundaries, which means that the page
462 // contains one or two partial chunks.
463 full_pages_chunk_count_max = page_size / chunk_size + 2;
464 same_chunk_count_per_page = false;
465 } else if (chunk_size > page_size && chunk_size % page_size == 0) {
466 // One chunk covers multiple pages, no cross overs.
467 full_pages_chunk_count_max = 1;
468 same_chunk_count_per_page = true;
469 } else if (chunk_size > page_size) {
470 // One chunk covers multiple pages, Some chunks are crossing page
471 // boundaries. Some pages contain one chunk, some contain two.
472 full_pages_chunk_count_max = 2;
473 same_chunk_count_per_page = false;
475 UNREACHABLE("All chunk_size/page_size ratios must be handled.");
478 PackedCounterArray<MemoryMapperT> counters(allocated_pages_count,
479 full_pages_chunk_count_max,
481 if (!counters.IsAllocated())
484 const uptr chunk_size_scaled = chunk_size >> kCompactPtrScale;
485 const uptr page_size_scaled = page_size >> kCompactPtrScale;
486 const uptr page_size_scaled_log = Log2(page_size_scaled);
488 // Iterate over free chunks and count how many free chunks affect each
490 if (chunk_size <= page_size && page_size % chunk_size == 0) {
491 // Each chunk affects one page only.
492 for (uptr i = 0; i < free_array_count; i++)
493 counters.Inc(free_array[i] >> page_size_scaled_log);
495 // In all other cases chunks might affect more than one page.
496 for (uptr i = 0; i < free_array_count; i++) {
498 free_array[i] >> page_size_scaled_log,
499 (free_array[i] + chunk_size_scaled - 1) >> page_size_scaled_log);
503 // Iterate over pages detecting ranges of pages with chunk counters equal
504 // to the expected number of chunks for the particular page.
505 FreePagesRangeTracker<MemoryMapperT> range_tracker(memory_mapper);
506 if (same_chunk_count_per_page) {
507 // Fast path, every page has the same number of chunks affecting it.
508 for (uptr i = 0; i < counters.GetCount(); i++)
509 range_tracker.NextPage(counters.Get(i) == full_pages_chunk_count_max);
511 // Show path, go through the pages keeping count how many chunks affect
514 chunk_size < page_size ? page_size_scaled / chunk_size_scaled : 1;
515 const uptr pnc = pn * chunk_size_scaled;
516 // The idea is to increment the current page pointer by the first chunk
517 // size, middle portion size (the portion of the page covered by chunks
518 // except the first and the last one) and then the last chunk size, adding
519 // up the number of chunks on the current page and checking on every step
520 // whether the page boundary was crossed.
521 uptr prev_page_boundary = 0;
522 uptr current_boundary = 0;
523 for (uptr i = 0; i < counters.GetCount(); i++) {
524 uptr page_boundary = prev_page_boundary + page_size_scaled;
525 uptr chunks_per_page = pn;
526 if (current_boundary < page_boundary) {
527 if (current_boundary > prev_page_boundary)
529 current_boundary += pnc;
530 if (current_boundary < page_boundary) {
532 current_boundary += chunk_size_scaled;
535 prev_page_boundary = page_boundary;
537 range_tracker.NextPage(counters.Get(i) == chunks_per_page);
540 range_tracker.Done();
544 friend class MemoryMapper;
546 ReservedAddressRange address_range;
547 static const char *AllocatorName() { return "sanitizer_allocator"; }
549 static const uptr kRegionSize = kSpaceSize / kNumClassesRounded;
550 // FreeArray is the array of free-d chunks (stored as 4-byte offsets).
551 // In the worst case it may reguire kRegionSize/SizeClassMap::kMinSize
552 // elements, but in reality this will not happen. For simplicity we
553 // dedicate 1/8 of the region's virtual space to FreeArray.
554 static const uptr kFreeArraySize = kRegionSize / 8;
556 static const bool kUsingConstantSpaceBeg = kSpaceBeg != ~(uptr)0;
557 uptr NonConstSpaceBeg;
558 uptr SpaceBeg() const {
559 return kUsingConstantSpaceBeg ? kSpaceBeg : NonConstSpaceBeg;
561 uptr SpaceEnd() const { return SpaceBeg() + kSpaceSize; }
562 // kRegionSize must be >= 2^32.
563 COMPILER_CHECK((kRegionSize) >= (1ULL << (SANITIZER_WORDSIZE / 2)));
564 // kRegionSize must be <= 2^36, see CompactPtrT.
565 COMPILER_CHECK((kRegionSize) <= (1ULL << (SANITIZER_WORDSIZE / 2 + 4)));
566 // Call mmap for user memory with at least this size.
567 static const uptr kUserMapSize = 1 << 16;
568 // Call mmap for metadata memory with at least this size.
569 static const uptr kMetaMapSize = 1 << 16;
570 // Call mmap for free array memory with at least this size.
571 static const uptr kFreeArrayMapSize = 1 << 16;
573 atomic_sint32_t release_to_os_interval_ms_;
580 struct ReleaseToOsInfo {
581 uptr n_freed_at_last_release;
583 u64 last_release_at_ns;
584 u64 last_released_bytes;
589 uptr num_freed_chunks; // Number of elements in the freearray.
590 uptr mapped_free_array; // Bytes mapped for freearray.
591 uptr allocated_user; // Bytes allocated for user memory.
592 uptr allocated_meta; // Bytes allocated for metadata.
593 uptr mapped_user; // Bytes mapped for user memory.
594 uptr mapped_meta; // Bytes mapped for metadata.
595 u32 rand_state; // Seed for random shuffle, used if kRandomShuffleChunks.
596 bool exhausted; // Whether region is out of space for new chunks.
598 ReleaseToOsInfo rtoi;
600 COMPILER_CHECK(sizeof(RegionInfo) >= kCacheLineSize);
602 RegionInfo *GetRegionInfo(uptr class_id) const {
603 CHECK_LT(class_id, kNumClasses);
604 RegionInfo *regions =
605 reinterpret_cast<RegionInfo *>(SpaceBeg() + kSpaceSize);
606 return ®ions[class_id];
609 uptr GetMetadataEnd(uptr region_beg) const {
610 return region_beg + kRegionSize - kFreeArraySize;
613 uptr GetChunkIdx(uptr chunk, uptr size) const {
614 if (!kUsingConstantSpaceBeg)
617 uptr offset = chunk % kRegionSize;
618 // Here we divide by a non-constant. This is costly.
619 // size always fits into 32-bits. If the offset fits too, use 32-bit div.
620 if (offset >> (SANITIZER_WORDSIZE / 2))
621 return offset / size;
622 return (u32)offset / (u32)size;
625 CompactPtrT *GetFreeArray(uptr region_beg) const {
626 return reinterpret_cast<CompactPtrT *>(GetMetadataEnd(region_beg));
629 bool MapWithCallback(uptr beg, uptr size) {
630 uptr mapped = address_range.Map(beg, size);
631 if (UNLIKELY(!mapped))
633 CHECK_EQ(beg, mapped);
634 MapUnmapCallback().OnMap(beg, size);
638 void MapWithCallbackOrDie(uptr beg, uptr size) {
639 CHECK_EQ(beg, address_range.MapOrDie(beg, size));
640 MapUnmapCallback().OnMap(beg, size);
643 void UnmapWithCallbackOrDie(uptr beg, uptr size) {
644 MapUnmapCallback().OnUnmap(beg, size);
645 address_range.Unmap(beg, size);
648 bool EnsureFreeArraySpace(RegionInfo *region, uptr region_beg,
649 uptr num_freed_chunks) {
650 uptr needed_space = num_freed_chunks * sizeof(CompactPtrT);
651 if (region->mapped_free_array < needed_space) {
652 uptr new_mapped_free_array = RoundUpTo(needed_space, kFreeArrayMapSize);
653 CHECK_LE(new_mapped_free_array, kFreeArraySize);
654 uptr current_map_end = reinterpret_cast<uptr>(GetFreeArray(region_beg)) +
655 region->mapped_free_array;
656 uptr new_map_size = new_mapped_free_array - region->mapped_free_array;
657 if (UNLIKELY(!MapWithCallback(current_map_end, new_map_size)))
659 region->mapped_free_array = new_mapped_free_array;
664 // Check whether this size class is exhausted.
665 bool IsRegionExhausted(RegionInfo *region, uptr class_id,
666 uptr additional_map_size) {
667 if (LIKELY(region->mapped_user + region->mapped_meta +
668 additional_map_size <= kRegionSize - kFreeArraySize))
670 if (!region->exhausted) {
671 region->exhausted = true;
672 Printf("%s: Out of memory. ", SanitizerToolName);
673 Printf("The process has exhausted %zuMB for size class %zu.\n",
674 kRegionSize >> 20, ClassIdToSize(class_id));
679 NOINLINE bool PopulateFreeArray(AllocatorStats *stat, uptr class_id,
680 RegionInfo *region, uptr requested_count) {
681 // region->mutex is held.
682 const uptr region_beg = GetRegionBeginBySizeClass(class_id);
683 const uptr size = ClassIdToSize(class_id);
685 const uptr total_user_bytes =
686 region->allocated_user + requested_count * size;
687 // Map more space for chunks, if necessary.
688 if (LIKELY(total_user_bytes > region->mapped_user)) {
689 if (UNLIKELY(region->mapped_user == 0)) {
690 if (!kUsingConstantSpaceBeg && kRandomShuffleChunks)
691 // The random state is initialized from ASLR.
692 region->rand_state = static_cast<u32>(region_beg >> 12);
693 // Postpone the first release to OS attempt for ReleaseToOSIntervalMs,
694 // preventing just allocated memory from being released sooner than
695 // necessary and also preventing extraneous ReleaseMemoryPagesToOS calls
696 // for short lived processes.
697 // Do it only when the feature is turned on, to avoid a potentially
698 // extraneous syscall.
699 if (ReleaseToOSIntervalMs() >= 0)
700 region->rtoi.last_release_at_ns = MonotonicNanoTime();
702 // Do the mmap for the user memory.
703 const uptr user_map_size =
704 RoundUpTo(total_user_bytes - region->mapped_user, kUserMapSize);
705 if (UNLIKELY(IsRegionExhausted(region, class_id, user_map_size)))
707 if (UNLIKELY(!MapWithCallback(region_beg + region->mapped_user,
710 stat->Add(AllocatorStatMapped, user_map_size);
711 region->mapped_user += user_map_size;
713 const uptr new_chunks_count =
714 (region->mapped_user - region->allocated_user) / size;
717 // Calculate the required space for metadata.
718 const uptr total_meta_bytes =
719 region->allocated_meta + new_chunks_count * kMetadataSize;
720 const uptr meta_map_size = (total_meta_bytes > region->mapped_meta) ?
721 RoundUpTo(total_meta_bytes - region->mapped_meta, kMetaMapSize) : 0;
722 // Map more space for metadata, if necessary.
724 if (UNLIKELY(IsRegionExhausted(region, class_id, meta_map_size)))
726 if (UNLIKELY(!MapWithCallback(
727 GetMetadataEnd(region_beg) - region->mapped_meta - meta_map_size,
730 region->mapped_meta += meta_map_size;
734 // If necessary, allocate more space for the free array and populate it with
735 // newly allocated chunks.
736 const uptr total_freed_chunks = region->num_freed_chunks + new_chunks_count;
737 if (UNLIKELY(!EnsureFreeArraySpace(region, region_beg, total_freed_chunks)))
739 CompactPtrT *free_array = GetFreeArray(region_beg);
740 for (uptr i = 0, chunk = region->allocated_user; i < new_chunks_count;
742 free_array[total_freed_chunks - 1 - i] = PointerToCompactPtr(0, chunk);
743 if (kRandomShuffleChunks)
744 RandomShuffle(&free_array[region->num_freed_chunks], new_chunks_count,
745 ®ion->rand_state);
747 // All necessary memory is mapped and now it is safe to advance all
748 // 'allocated_*' counters.
749 region->num_freed_chunks += new_chunks_count;
750 region->allocated_user += new_chunks_count * size;
751 CHECK_LE(region->allocated_user, region->mapped_user);
752 region->allocated_meta += new_chunks_count * kMetadataSize;
753 CHECK_LE(region->allocated_meta, region->mapped_meta);
754 region->exhausted = false;
756 // TODO(alekseyshl): Consider bumping last_release_at_ns here to prevent
757 // MaybeReleaseToOS from releasing just allocated pages or protect these
758 // not yet used chunks some other way.
765 MemoryMapper(const ThisT& base_allocator, uptr class_id)
766 : allocator(base_allocator),
767 region_base(base_allocator.GetRegionBeginBySizeClass(class_id)),
768 released_ranges_count(0),
772 uptr GetReleasedRangesCount() const {
773 return released_ranges_count;
776 uptr GetReleasedBytes() const {
777 return released_bytes;
780 uptr MapPackedCounterArrayBuffer(uptr buffer_size) {
781 // TODO(alekseyshl): The idea to explore is to check if we have enough
782 // space between num_freed_chunks*sizeof(CompactPtrT) and
783 // mapped_free_array to fit buffer_size bytes and use that space instead
784 // of mapping a temporary one.
785 return reinterpret_cast<uptr>(
786 MmapOrDieOnFatalError(buffer_size, "ReleaseToOSPageCounters"));
789 void UnmapPackedCounterArrayBuffer(uptr buffer, uptr buffer_size) {
790 UnmapOrDie(reinterpret_cast<void *>(buffer), buffer_size);
793 // Releases [from, to) range of pages back to OS.
794 void ReleasePageRangeToOS(CompactPtrT from, CompactPtrT to) {
795 const uptr from_page = allocator.CompactPtrToPointer(region_base, from);
796 const uptr to_page = allocator.CompactPtrToPointer(region_base, to);
797 ReleaseMemoryPagesToOS(from_page, to_page);
798 released_ranges_count++;
799 released_bytes += to_page - from_page;
803 const ThisT& allocator;
804 const uptr region_base;
805 uptr released_ranges_count;
809 // Attempts to release RAM occupied by freed chunks back to OS. The region is
810 // expected to be locked.
811 void MaybeReleaseToOS(uptr class_id, bool force) {
812 RegionInfo *region = GetRegionInfo(class_id);
813 const uptr chunk_size = ClassIdToSize(class_id);
814 const uptr page_size = GetPageSizeCached();
816 uptr n = region->num_freed_chunks;
817 if (n * chunk_size < page_size)
818 return; // No chance to release anything.
819 if ((region->stats.n_freed -
820 region->rtoi.n_freed_at_last_release) * chunk_size < page_size) {
821 return; // Nothing new to release.
825 s32 interval_ms = ReleaseToOSIntervalMs();
829 if (region->rtoi.last_release_at_ns + interval_ms * 1000000ULL >
830 MonotonicNanoTime()) {
831 return; // Memory was returned recently.
835 MemoryMapper memory_mapper(*this, class_id);
837 ReleaseFreeMemoryToOS<MemoryMapper>(
838 GetFreeArray(GetRegionBeginBySizeClass(class_id)), n, chunk_size,
839 RoundUpTo(region->allocated_user, page_size) / page_size,
842 if (memory_mapper.GetReleasedRangesCount() > 0) {
843 region->rtoi.n_freed_at_last_release = region->stats.n_freed;
844 region->rtoi.num_releases += memory_mapper.GetReleasedRangesCount();
845 region->rtoi.last_released_bytes = memory_mapper.GetReleasedBytes();
847 region->rtoi.last_release_at_ns = MonotonicNanoTime();