aboutsummaryrefslogtreecommitdiffstats
path: root/lib/scudo/standalone/primary64.h
blob: 035182b33ef4c21fe1db7024670e3f01975eb4fc (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
//===-- primary64.h ---------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef SCUDO_PRIMARY64_H_
#define SCUDO_PRIMARY64_H_

#include "bytemap.h"
#include "common.h"
#include "list.h"
#include "local_cache.h"
#include "release.h"
#include "stats.h"
#include "string_utils.h"

namespace scudo {

// SizeClassAllocator64 is an allocator tuned for 64-bit address space.
//
// It starts by reserving NumClasses * 2^RegionSizeLog bytes, equally divided in
// Regions, specific to each size class. Note that the base of that mapping is
// random (based to the platform specific map() capabilities), and that each
// Region actually starts at a random offset from its base.
//
// Regions are mapped incrementally on demand to fulfill allocation requests,
// those mappings being split into equally sized Blocks based on the size class
// they belong to. The Blocks created are shuffled to prevent predictable
// address patterns (the predictability increases with the size of the Blocks).
//
// The 1st Region (for size class 0) holds the TransferBatches. This is a
// structure used to transfer arrays of available pointers from the class size
// freelist to the thread specific freelist, and back.
//
// The memory used by this allocator is never unmapped, but can be partially
// released it the platform allows for it.

template <class SizeClassMapT, uptr RegionSizeLog> class SizeClassAllocator64 {
public:
  typedef SizeClassMapT SizeClassMap;
  typedef SizeClassAllocator64<SizeClassMap, RegionSizeLog> ThisT;
  typedef SizeClassAllocatorLocalCache<ThisT> CacheT;
  typedef typename CacheT::TransferBatch TransferBatch;

  static uptr getSizeByClassId(uptr ClassId) {
    return (ClassId == SizeClassMap::BatchClassId)
               ? sizeof(TransferBatch)
               : SizeClassMap::getSizeByClassId(ClassId);
  }

  static bool canAllocate(uptr Size) { return Size <= SizeClassMap::MaxSize; }

  void initLinkerInitialized(s32 ReleaseToOsInterval) {
    // Reserve the space required for the Primary.
    PrimaryBase = reinterpret_cast<uptr>(
        map(nullptr, PrimarySize, "scudo:primary", MAP_NOACCESS, &Data));

    RegionInfoArray = reinterpret_cast<RegionInfo *>(
        map(nullptr, sizeof(RegionInfo) * NumClasses, "scudo:regioninfo"));
    DCHECK_EQ(reinterpret_cast<uptr>(RegionInfoArray) % SCUDO_CACHE_LINE_SIZE,
              0);

    u32 Seed;
    if (UNLIKELY(!getRandom(reinterpret_cast<void *>(&Seed), sizeof(Seed))))
      Seed = static_cast<u32>(getMonotonicTime() ^ (PrimaryBase >> 12));
    const uptr PageSize = getPageSizeCached();
    for (uptr I = 0; I < NumClasses; I++) {
      RegionInfo *Region = getRegionInfo(I);
      // The actual start of a region is offseted by a random number of pages.
      Region->RegionBeg =
          getRegionBaseByClassId(I) + (getRandomModN(&Seed, 16) + 1) * PageSize;
      // Releasing smaller size classes doesn't necessarily yield to a
      // meaningful RSS impact: there are more blocks per page, they are
      // randomized around, and thus pages are less likely to be entirely empty.
      // On top of this, attempting to release those require more iterations and
      // memory accesses which ends up being fairly costly. The current lower
      // limit is mostly arbitrary and based on empirical observations.
      // TODO(kostyak): make the lower limit a runtime option
      Region->CanRelease = (ReleaseToOsInterval > 0) &&
                           (I != SizeClassMap::BatchClassId) &&
                           (getSizeByClassId(I) >= (PageSize / 32));
      Region->RandState = getRandomU32(&Seed);
    }
    ReleaseToOsIntervalMs = ReleaseToOsInterval;
  }
  void init(s32 ReleaseToOsInterval) {
    memset(this, 0, sizeof(*this));
    initLinkerInitialized(ReleaseToOsInterval);
  }

  void unmapTestOnly() {
    unmap(reinterpret_cast<void *>(PrimaryBase), PrimarySize, UNMAP_ALL, &Data);
    unmap(reinterpret_cast<void *>(RegionInfoArray),
          sizeof(RegionInfo) * NumClasses);
  }

  TransferBatch *popBatch(CacheT *C, uptr ClassId) {
    DCHECK_LT(ClassId, NumClasses);
    RegionInfo *Region = getRegionInfo(ClassId);
    ScopedLock L(Region->Mutex);
    TransferBatch *B = Region->FreeList.front();
    if (B)
      Region->FreeList.pop_front();
    else {
      B = populateFreeList(C, ClassId, Region);
      if (UNLIKELY(!B))
        return nullptr;
    }
    DCHECK_GT(B->getCount(), 0);
    Region->Stats.PoppedBlocks += B->getCount();
    return B;
  }

  void pushBatch(uptr ClassId, TransferBatch *B) {
    DCHECK_GT(B->getCount(), 0);
    RegionInfo *Region = getRegionInfo(ClassId);
    ScopedLock L(Region->Mutex);
    Region->FreeList.push_front(B);
    Region->Stats.PushedBlocks += B->getCount();
    if (Region->CanRelease)
      releaseToOSMaybe(Region, ClassId);
  }

  void disable() {
    for (uptr I = 0; I < NumClasses; I++)
      getRegionInfo(I)->Mutex.lock();
  }

  void enable() {
    for (sptr I = static_cast<sptr>(NumClasses) - 1; I >= 0; I--)
      getRegionInfo(I)->Mutex.unlock();
  }

  template <typename F> void iterateOverBlocks(F Callback) const {
    for (uptr I = 1; I < NumClasses; I++) {
      const RegionInfo *Region = getRegionInfo(I);
      const uptr BlockSize = getSizeByClassId(I);
      const uptr From = Region->RegionBeg;
      const uptr To = From + Region->AllocatedUser;
      for (uptr Block = From; Block < To; Block += BlockSize)
        Callback(Block);
    }
  }

  void printStats() const {
    // TODO(kostyak): get the RSS per region.
    uptr TotalMapped = 0;
    uptr PoppedBlocks = 0;
    uptr PushedBlocks = 0;
    for (uptr I = 0; I < NumClasses; I++) {
      RegionInfo *Region = getRegionInfo(I);
      if (Region->MappedUser)
        TotalMapped += Region->MappedUser;
      PoppedBlocks += Region->Stats.PoppedBlocks;
      PushedBlocks += Region->Stats.PushedBlocks;
    }
    Printf("Stats: Primary64: %zuM mapped (%zuM rss) in %zu allocations; "
           "remains %zu\n",
           TotalMapped >> 20, 0, PoppedBlocks, PoppedBlocks - PushedBlocks);

    for (uptr I = 0; I < NumClasses; I++)
      printStats(I, 0);
  }

  void releaseToOS() {
    for (uptr I = 0; I < NumClasses; I++) {
      if (I == SizeClassMap::BatchClassId)
        continue;
      RegionInfo *Region = getRegionInfo(I);
      ScopedLock L(Region->Mutex);
      releaseToOSMaybe(Region, I, /*Force=*/true);
    }
  }

private:
  static const uptr RegionSize = 1UL << RegionSizeLog;
  static const uptr NumClasses = SizeClassMap::NumClasses;
  static const uptr PrimarySize = RegionSize * NumClasses;

  // Call map for user memory with at least this size.
  static const uptr MapSizeIncrement = 1UL << 16;

  struct RegionStats {
    uptr PoppedBlocks;
    uptr PushedBlocks;
  };

  struct ReleaseToOsInfo {
    uptr PushedBlocksAtLastRelease;
    uptr RangesReleased;
    uptr LastReleasedBytes;
    u64 LastReleaseAtNs;
  };

  struct ALIGNED(SCUDO_CACHE_LINE_SIZE) RegionInfo {
    HybridMutex Mutex;
    IntrusiveList<TransferBatch> FreeList;
    RegionStats Stats;
    bool CanRelease;
    bool Exhausted;
    u32 RandState;
    uptr RegionBeg;
    uptr MappedUser;    // Bytes mapped for user memory.
    uptr AllocatedUser; // Bytes allocated for user memory.
    MapPlatformData Data;
    ReleaseToOsInfo ReleaseInfo;
  };
  COMPILER_CHECK(sizeof(RegionInfo) % SCUDO_CACHE_LINE_SIZE == 0);

  uptr PrimaryBase;
  RegionInfo *RegionInfoArray;
  MapPlatformData Data;
  s32 ReleaseToOsIntervalMs;

  RegionInfo *getRegionInfo(uptr ClassId) const {
    DCHECK_LT(ClassId, NumClasses);
    return &RegionInfoArray[ClassId];
  }

  uptr getRegionBaseByClassId(uptr ClassId) const {
    return PrimaryBase + (ClassId << RegionSizeLog);
  }

  bool populateBatches(CacheT *C, RegionInfo *Region, uptr ClassId,
                       TransferBatch **CurrentBatch, u32 MaxCount,
                       void **PointersArray, u32 Count) {
    // No need to shuffle the batches size class.
    if (ClassId != SizeClassMap::BatchClassId)
      shuffle(PointersArray, Count, &Region->RandState);
    TransferBatch *B = *CurrentBatch;
    for (uptr I = 0; I < Count; I++) {
      if (B && B->getCount() == MaxCount) {
        Region->FreeList.push_back(B);
        B = nullptr;
      }
      if (!B) {
        B = C->createBatch(ClassId, PointersArray[I]);
        if (UNLIKELY(!B))
          return false;
        B->clear();
      }
      B->add(PointersArray[I]);
    }
    *CurrentBatch = B;
    return true;
  }

  NOINLINE TransferBatch *populateFreeList(CacheT *C, uptr ClassId,
                                           RegionInfo *Region) {
    const uptr Size = getSizeByClassId(ClassId);
    const u32 MaxCount = TransferBatch::getMaxCached(Size);

    const uptr RegionBeg = Region->RegionBeg;
    const uptr MappedUser = Region->MappedUser;
    const uptr TotalUserBytes = Region->AllocatedUser + MaxCount * Size;
    // Map more space for blocks, if necessary.
    if (LIKELY(TotalUserBytes > MappedUser)) {
      // Do the mmap for the user memory.
      const uptr UserMapSize =
          roundUpTo(TotalUserBytes - MappedUser, MapSizeIncrement);
      const uptr RegionBase = RegionBeg - getRegionBaseByClassId(ClassId);
      if (UNLIKELY(RegionBase + MappedUser + UserMapSize > RegionSize)) {
        if (!Region->Exhausted) {
          Region->Exhausted = true;
          printStats();
          Printf(
              "Scudo OOM: The process has Exhausted %zuM for size class %zu.\n",
              RegionSize >> 20, Size);
        }
        return nullptr;
      }
      if (MappedUser == 0)
        Region->Data = Data;
      if (UNLIKELY(!map(reinterpret_cast<void *>(RegionBeg + MappedUser),
                        UserMapSize, "scudo:primary",
                        MAP_ALLOWNOMEM | MAP_RESIZABLE, &Region->Data)))
        return nullptr;
      Region->MappedUser += UserMapSize;
      C->getStats().add(StatMapped, UserMapSize);
    }

    const uptr NumberOfBlocks = Min(
        8UL * MaxCount, (Region->MappedUser - Region->AllocatedUser) / Size);
    DCHECK_GT(NumberOfBlocks, 0);

    TransferBatch *B = nullptr;
    constexpr uptr ShuffleArraySize = 48;
    void *ShuffleArray[ShuffleArraySize];
    u32 Count = 0;
    const uptr P = RegionBeg + Region->AllocatedUser;
    const uptr AllocatedUser = NumberOfBlocks * Size;
    for (uptr I = P; I < P + AllocatedUser; I += Size) {
      ShuffleArray[Count++] = reinterpret_cast<void *>(I);
      if (Count == ShuffleArraySize) {
        if (UNLIKELY(!populateBatches(C, Region, ClassId, &B, MaxCount,
                                      ShuffleArray, Count)))
          return nullptr;
        Count = 0;
      }
    }
    if (Count) {
      if (UNLIKELY(!populateBatches(C, Region, ClassId, &B, MaxCount,
                                    ShuffleArray, Count)))
        return nullptr;
    }
    DCHECK(B);
    CHECK_GT(B->getCount(), 0);

    Region->AllocatedUser += AllocatedUser;
    Region->Exhausted = false;
    if (Region->CanRelease)
      Region->ReleaseInfo.LastReleaseAtNs = getMonotonicTime();

    return B;
  }

  void printStats(uptr ClassId, uptr Rss) const {
    RegionInfo *Region = getRegionInfo(ClassId);
    if (Region->MappedUser == 0)
      return;
    const uptr InUse = Region->Stats.PoppedBlocks - Region->Stats.PushedBlocks;
    const uptr AvailableChunks =
        Region->AllocatedUser / getSizeByClassId(ClassId);
    Printf("%s %02zu (%6zu): mapped: %6zuK popped: %7zu pushed: %7zu inuse: "
           "%6zu avail: %6zu rss: %6zuK releases: %6zu last released: %6zuK "
           "region: 0x%zx (0x%zx)\n",
           Region->Exhausted ? "F" : " ", ClassId, getSizeByClassId(ClassId),
           Region->MappedUser >> 10, Region->Stats.PoppedBlocks,
           Region->Stats.PushedBlocks, InUse, AvailableChunks, Rss >> 10,
           Region->ReleaseInfo.RangesReleased,
           Region->ReleaseInfo.LastReleasedBytes >> 10, Region->RegionBeg,
           getRegionBaseByClassId(ClassId));
  }

  NOINLINE void releaseToOSMaybe(RegionInfo *Region, uptr ClassId,
                                 bool Force = false) {
    const uptr BlockSize = getSizeByClassId(ClassId);
    const uptr PageSize = getPageSizeCached();

    CHECK_GE(Region->Stats.PoppedBlocks, Region->Stats.PushedBlocks);
    const uptr N = Region->Stats.PoppedBlocks - Region->Stats.PushedBlocks;
    if (N * BlockSize < PageSize)
      return; // No chance to release anything.
    if ((Region->Stats.PushedBlocks -
         Region->ReleaseInfo.PushedBlocksAtLastRelease) *
            BlockSize <
        PageSize) {
      return; // Nothing new to release.
    }

    if (!Force) {
      const s32 IntervalMs = ReleaseToOsIntervalMs;
      if (IntervalMs < 0)
        return;
      if (Region->ReleaseInfo.LastReleaseAtNs + IntervalMs * 1000000ULL >
          getMonotonicTime()) {
        return; // Memory was returned recently.
      }
    }

    ReleaseRecorder Recorder(Region->RegionBeg, &Region->Data);
    releaseFreeMemoryToOS(&Region->FreeList, Region->RegionBeg,
                          roundUpTo(Region->AllocatedUser, PageSize) / PageSize,
                          BlockSize, &Recorder);

    if (Recorder.getReleasedRangesCount() > 0) {
      Region->ReleaseInfo.PushedBlocksAtLastRelease =
          Region->Stats.PushedBlocks;
      Region->ReleaseInfo.RangesReleased += Recorder.getReleasedRangesCount();
      Region->ReleaseInfo.LastReleasedBytes = Recorder.getReleasedBytes();
    }
    Region->ReleaseInfo.LastReleaseAtNs = getMonotonicTime();
  }
};

} // namespace scudo

#endif // SCUDO_PRIMARY64_H_