libsanitizer/sanitizer_common/sanitizer_allocator_primary32.h

   1 //===-- sanitizer_allocator_primary32.h -------------------------*- C++ -*-===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // Part of the Sanitizer Allocator.
   9 //
  10 //===----------------------------------------------------------------------===//
  11 #ifndef SANITIZER_ALLOCATOR_H
  12 #error This file must be included inside sanitizer_allocator.h
  13 #endif
  14
  15 template<class SizeClassAllocator> struct SizeClassAllocator32LocalCache;
  16
  17 // SizeClassAllocator32 -- allocator for 32-bit address space.
  18 // This allocator can theoretically be used on 64-bit arch, but there it is less
  19 // efficient than SizeClassAllocator64.
  20 //
  21 // [kSpaceBeg, kSpaceBeg + kSpaceSize) is the range of addresses which can
  22 // be returned by MmapOrDie().
  23 //
  24 // Region:
  25 //   a result of a single call to MmapAlignedOrDieOnFatalError(kRegionSize,
  26 //                                                             kRegionSize).
  27 // Since the regions are aligned by kRegionSize, there are exactly
  28 // kNumPossibleRegions possible regions in the address space and so we keep
  29 // a ByteMap possible_regions to store the size classes of each Region.
  30 // 0 size class means the region is not used by the allocator.
  31 //
  32 // One Region is used to allocate chunks of a single size class.
  33 // A Region looks like this:
  34 // UserChunk1 .. UserChunkN <gap> MetaChunkN .. MetaChunk1
  35 //
  36 // In order to avoid false sharing the objects of this class should be
  37 // chache-line aligned.
  38
  39 struct SizeClassAllocator32FlagMasks {  //  Bit masks.
  40   enum {
  41     kRandomShuffleChunks = 1,
  42     kUseSeparateSizeClassForBatch = 2,
  43   };
  44 };
  45
  46 template <class Params>
  47 class SizeClassAllocator32 {
  48  public:
  49   static const uptr kSpaceBeg = Params::kSpaceBeg;
  50   static const u64 kSpaceSize = Params::kSpaceSize;
  51   static const uptr kMetadataSize = Params::kMetadataSize;
  52   typedef typename Params::SizeClassMap SizeClassMap;
  53   static const uptr kRegionSizeLog = Params::kRegionSizeLog;
  54   typedef typename Params::ByteMap ByteMap;
  55   typedef typename Params::MapUnmapCallback MapUnmapCallback;
  56
  57   static const bool kRandomShuffleChunks = Params::kFlags &
  58       SizeClassAllocator32FlagMasks::kRandomShuffleChunks;
  59   static const bool kUseSeparateSizeClassForBatch = Params::kFlags &
  60       SizeClassAllocator32FlagMasks::kUseSeparateSizeClassForBatch;
  61
  62   struct TransferBatch {
  63     static const uptr kMaxNumCached = SizeClassMap::kMaxNumCachedHint - 2;
  64     void SetFromArray(void *batch[], uptr count) {
  65       DCHECK_LE(count, kMaxNumCached);
  66       count_ = count;
  67       for (uptr i = 0; i < count; i++)
  68         batch_[i] = batch[i];
  69     }
  70     uptr Count() const { return count_; }
  71     void Clear() { count_ = 0; }
  72     void Add(void *ptr) {
  73       batch_[count_++] = ptr;
  74       DCHECK_LE(count_, kMaxNumCached);
  75     }
  76     void CopyToArray(void *to_batch[]) const {
  77       for (uptr i = 0, n = Count(); i < n; i++)
  78         to_batch[i] = batch_[i];
  79     }
  80
  81     // How much memory do we need for a batch containing n elements.
  82     static uptr AllocationSizeRequiredForNElements(uptr n) {
  83       return sizeof(uptr) * 2 + sizeof(void *) * n;
  84     }
  85     static uptr MaxCached(uptr size) {
  86       return Min(kMaxNumCached, SizeClassMap::MaxCachedHint(size));
  87     }
  88
  89     TransferBatch *next;
  90
  91    private:
  92     uptr count_;
  93     void *batch_[kMaxNumCached];
  94   };
  95
  96   static const uptr kBatchSize = sizeof(TransferBatch);
  97   COMPILER_CHECK((kBatchSize & (kBatchSize - 1)) == 0);
  98   COMPILER_CHECK(kBatchSize == SizeClassMap::kMaxNumCachedHint * sizeof(uptr));
  99
 100   static uptr ClassIdToSize(uptr class_id) {
 101     return (class_id == SizeClassMap::kBatchClassID) ?
 102         kBatchSize : SizeClassMap::Size(class_id);
 103   }
 104
 105   typedef SizeClassAllocator32<Params> ThisT;
 106   typedef SizeClassAllocator32LocalCache<ThisT> AllocatorCache;
 107
 108   void Init(s32 release_to_os_interval_ms) {
 109     possible_regions.Init();
 110     internal_memset(size_class_info_array, 0, sizeof(size_class_info_array));
 111   }
 112
 113   s32 ReleaseToOSIntervalMs() const {
 114     return kReleaseToOSIntervalNever;
 115   }
 116
 117   void SetReleaseToOSIntervalMs(s32 release_to_os_interval_ms) {
 118     // This is empty here. Currently only implemented in 64-bit allocator.
 119   }
 120
 121   void ForceReleaseToOS() {
 122     // Currently implemented in 64-bit allocator only.
 123   }
 124
 125   void *MapWithCallback(uptr size) {
 126     void *res = MmapOrDie(size, PrimaryAllocatorName);
 127     MapUnmapCallback().OnMap((uptr)res, size);
 128     return res;
 129   }
 130
 131   void UnmapWithCallback(uptr beg, uptr size) {
 132     MapUnmapCallback().OnUnmap(beg, size);
 133     UnmapOrDie(reinterpret_cast<void *>(beg), size);
 134   }
 135
 136   static bool CanAllocate(uptr size, uptr alignment) {
 137     return size <= SizeClassMap::kMaxSize &&
 138       alignment <= SizeClassMap::kMaxSize;
 139   }
 140
 141   void *GetMetaData(const void *p) {
 142     CHECK(PointerIsMine(p));
 143     uptr mem = reinterpret_cast<uptr>(p);
 144     uptr beg = ComputeRegionBeg(mem);
 145     uptr size = ClassIdToSize(GetSizeClass(p));
 146     u32 offset = mem - beg;
 147     uptr n = offset / (u32)size;  // 32-bit division
 148     uptr meta = (beg + kRegionSize) - (n + 1) * kMetadataSize;
 149     return reinterpret_cast<void*>(meta);
 150   }
 151
 152   NOINLINE TransferBatch *AllocateBatch(AllocatorStats *stat, AllocatorCache *c,
 153                                         uptr class_id) {
 154     DCHECK_LT(class_id, kNumClasses);
 155     SizeClassInfo *sci = GetSizeClassInfo(class_id);
 156     SpinMutexLock l(&sci->mutex);
 157     if (sci->free_list.empty()) {
 158       if (UNLIKELY(!PopulateFreeList(stat, c, sci, class_id)))
 159         return nullptr;
 160       DCHECK(!sci->free_list.empty());
 161     }
 162     TransferBatch *b = sci->free_list.front();
 163     sci->free_list.pop_front();
 164     return b;
 165   }
 166
 167   NOINLINE void DeallocateBatch(AllocatorStats *stat, uptr class_id,
 168                                 TransferBatch *b) {
 169     DCHECK_LT(class_id, kNumClasses);
 170     CHECK_GT(b->Count(), 0);
 171     SizeClassInfo *sci = GetSizeClassInfo(class_id);
 172     SpinMutexLock l(&sci->mutex);
 173     sci->free_list.push_front(b);
 174   }
 175
 176   bool PointerIsMine(const void *p) {
 177     uptr mem = reinterpret_cast<uptr>(p);
 178     if (mem < kSpaceBeg || mem >= kSpaceBeg + kSpaceSize)
 179       return false;
 180     return GetSizeClass(p) != 0;
 181   }
 182
 183   uptr GetSizeClass(const void *p) {
 184     return possible_regions[ComputeRegionId(reinterpret_cast<uptr>(p))];
 185   }
 186
 187   void *GetBlockBegin(const void *p) {
 188     CHECK(PointerIsMine(p));
 189     uptr mem = reinterpret_cast<uptr>(p);
 190     uptr beg = ComputeRegionBeg(mem);
 191     uptr size = ClassIdToSize(GetSizeClass(p));
 192     u32 offset = mem - beg;
 193     u32 n = offset / (u32)size;  // 32-bit division
 194     uptr res = beg + (n * (u32)size);
 195     return reinterpret_cast<void*>(res);
 196   }
 197
 198   uptr GetActuallyAllocatedSize(void *p) {
 199     CHECK(PointerIsMine(p));
 200     return ClassIdToSize(GetSizeClass(p));
 201   }
 202
 203   uptr ClassID(uptr size) { return SizeClassMap::ClassID(size); }
 204
 205   uptr TotalMemoryUsed() {
 206     // No need to lock here.
 207     uptr res = 0;
 208     for (uptr i = 0; i < kNumPossibleRegions; i++)
 209       if (possible_regions[i])
 210         res += kRegionSize;
 211     return res;
 212   }
 213
 214   void TestOnlyUnmap() {
 215     for (uptr i = 0; i < kNumPossibleRegions; i++)
 216       if (possible_regions[i])
 217         UnmapWithCallback((i * kRegionSize), kRegionSize);
 218   }
 219
 220   // ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone
 221   // introspection API.
 222   void ForceLock() {
 223     for (uptr i = 0; i < kNumClasses; i++) {
 224       GetSizeClassInfo(i)->mutex.Lock();
 225     }
 226   }
 227
 228   void ForceUnlock() {
 229     for (int i = kNumClasses - 1; i >= 0; i--) {
 230       GetSizeClassInfo(i)->mutex.Unlock();
 231     }
 232   }
 233
 234   // Iterate over all existing chunks.
 235   // The allocator must be locked when calling this function.
 236   void ForEachChunk(ForEachChunkCallback callback, void *arg) {
 237     for (uptr region = 0; region < kNumPossibleRegions; region++)
 238       if (possible_regions[region]) {
 239         uptr chunk_size = ClassIdToSize(possible_regions[region]);
 240         uptr max_chunks_in_region = kRegionSize / (chunk_size + kMetadataSize);
 241         uptr region_beg = region * kRegionSize;
 242         for (uptr chunk = region_beg;
 243              chunk < region_beg + max_chunks_in_region * chunk_size;
 244              chunk += chunk_size) {
 245           // Too slow: CHECK_EQ((void *)chunk, GetBlockBegin((void *)chunk));
 246           callback(chunk, arg);
 247         }
 248       }
 249   }
 250
 251   void PrintStats() {}
 252
 253   static uptr AdditionalSize() { return 0; }
 254
 255   typedef SizeClassMap SizeClassMapT;
 256   static const uptr kNumClasses = SizeClassMap::kNumClasses;
 257
 258  private:
 259   static const uptr kRegionSize = 1 << kRegionSizeLog;
 260   static const uptr kNumPossibleRegions = kSpaceSize / kRegionSize;
 261
 262   struct ALIGNED(SANITIZER_CACHE_LINE_SIZE) SizeClassInfo {
 263     StaticSpinMutex mutex;
 264     IntrusiveList<TransferBatch> free_list;
 265     u32 rand_state;
 266   };
 267   COMPILER_CHECK(sizeof(SizeClassInfo) % kCacheLineSize == 0);
 268
 269   uptr ComputeRegionId(uptr mem) {
 270     const uptr res = mem >> kRegionSizeLog;
 271     CHECK_LT(res, kNumPossibleRegions);
 272     return res;
 273   }
 274
 275   uptr ComputeRegionBeg(uptr mem) {
 276     return mem & ~(kRegionSize - 1);
 277   }
 278
 279   uptr AllocateRegion(AllocatorStats *stat, uptr class_id) {
 280     DCHECK_LT(class_id, kNumClasses);
 281     const uptr res = reinterpret_cast<uptr>(MmapAlignedOrDieOnFatalError(
 282         kRegionSize, kRegionSize, PrimaryAllocatorName));
 283     if (UNLIKELY(!res))
 284       return 0;
 285     MapUnmapCallback().OnMap(res, kRegionSize);
 286     stat->Add(AllocatorStatMapped, kRegionSize);
 287     CHECK(IsAligned(res, kRegionSize));
 288     possible_regions.set(ComputeRegionId(res), static_cast<u8>(class_id));
 289     return res;
 290   }
 291
 292   SizeClassInfo *GetSizeClassInfo(uptr class_id) {
 293     DCHECK_LT(class_id, kNumClasses);
 294     return &size_class_info_array[class_id];
 295   }
 296
 297   bool PopulateBatches(AllocatorCache *c, SizeClassInfo *sci, uptr class_id,
 298                        TransferBatch **current_batch, uptr max_count,
 299                        uptr *pointers_array, uptr count) {
 300     // If using a separate class for batches, we do not need to shuffle it.
 301     if (kRandomShuffleChunks && (!kUseSeparateSizeClassForBatch ||
 302         class_id != SizeClassMap::kBatchClassID))
 303       RandomShuffle(pointers_array, count, &sci->rand_state);
 304     TransferBatch *b = *current_batch;
 305     for (uptr i = 0; i < count; i++) {
 306       if (!b) {
 307         b = c->CreateBatch(class_id, this, (TransferBatch*)pointers_array[i]);
 308         if (UNLIKELY(!b))
 309           return false;
 310         b->Clear();
 311       }
 312       b->Add((void*)pointers_array[i]);
 313       if (b->Count() == max_count) {
 314         sci->free_list.push_back(b);
 315         b = nullptr;
 316       }
 317     }
 318     *current_batch = b;
 319     return true;
 320   }
 321
 322   bool PopulateFreeList(AllocatorStats *stat, AllocatorCache *c,
 323                         SizeClassInfo *sci, uptr class_id) {
 324     const uptr region = AllocateRegion(stat, class_id);
 325     if (UNLIKELY(!region))
 326       return false;
 327     if (kRandomShuffleChunks)
 328       if (UNLIKELY(sci->rand_state == 0))
 329         // The random state is initialized from ASLR (PIE) and time.
 330         sci->rand_state = reinterpret_cast<uptr>(sci) ^ NanoTime();
 331     const uptr size = ClassIdToSize(class_id);
 332     const uptr n_chunks = kRegionSize / (size + kMetadataSize);
 333     const uptr max_count = TransferBatch::MaxCached(size);
 334     DCHECK_GT(max_count, 0);
 335     TransferBatch *b = nullptr;
 336     constexpr uptr kShuffleArraySize = 48;
 337     uptr shuffle_array[kShuffleArraySize];
 338     uptr count = 0;
 339     for (uptr i = region; i < region + n_chunks * size; i += size) {
 340       shuffle_array[count++] = i;
 341       if (count == kShuffleArraySize) {
 342         if (UNLIKELY(!PopulateBatches(c, sci, class_id, &b, max_count,
 343                                       shuffle_array, count)))
 344           return false;
 345         count = 0;
 346       }
 347     }
 348     if (count) {
 349       if (UNLIKELY(!PopulateBatches(c, sci, class_id, &b, max_count,
 350                                     shuffle_array, count)))
 351         return false;
 352     }
 353     if (b) {
 354       CHECK_GT(b->Count(), 0);
 355       sci->free_list.push_back(b);
 356     }
 357     return true;
 358   }
 359
 360   ByteMap possible_regions;
 361   SizeClassInfo size_class_info_array[kNumClasses];
 362 };