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llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_allocator.h

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//===-- sanitizer_allocator.h -----------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Specialized memory allocator for ThreadSanitizer, MemorySanitizer, etc.
//
//===----------------------------------------------------------------------===//
#ifndef SANITIZER_ALLOCATOR_H
#define SANITIZER_ALLOCATOR_H
#include "sanitizer_internal_defs.h"
#include "sanitizer_common.h"
#include "sanitizer_libc.h"
#include "sanitizer_list.h"
#include "sanitizer_mutex.h"
#include "sanitizer_lfstack.h"
namespace __sanitizer {
// SizeClassMap maps allocation sizes into size classes and back.
// Class 0 corresponds to size 0.
// Classes 1 - 16 correspond to sizes 16 to 256 (size = class_id * 16).
// Next 4 classes: 256 + i * 64 (i = 1 to 4).
// Next 4 classes: 512 + i * 128 (i = 1 to 4).
// ...
// Next 4 classes: 2^k + i * 2^(k-2) (i = 1 to 4).
// Last class corresponds to kMaxSize = 1 << kMaxSizeLog.
//
// This structure of the size class map gives us:
// - Efficient table-free class-to-size and size-to-class functions.
// - Difference between two consequent size classes is betweed 14% and 25%
//
// This class also gives a hint to a thread-caching allocator about the amount
// of chunks that need to be cached per-thread:
// - kMaxNumCached is the maximal number of chunks per size class.
// - (1 << kMaxBytesCachedLog) is the maximal number of bytes per size class.
//
// Part of output of SizeClassMap::Print():
// c00 => s: 0 diff: +0 00% l 0 cached: 0 0; id 0
// c01 => s: 16 diff: +16 00% l 4 cached: 256 4096; id 1
// c02 => s: 32 diff: +16 100% l 5 cached: 256 8192; id 2
// c03 => s: 48 diff: +16 50% l 5 cached: 256 12288; id 3
// c04 => s: 64 diff: +16 33% l 6 cached: 256 16384; id 4
// c05 => s: 80 diff: +16 25% l 6 cached: 256 20480; id 5
// c06 => s: 96 diff: +16 20% l 6 cached: 256 24576; id 6
// c07 => s: 112 diff: +16 16% l 6 cached: 256 28672; id 7
//
// c08 => s: 128 diff: +16 14% l 7 cached: 256 32768; id 8
// c09 => s: 144 diff: +16 12% l 7 cached: 256 36864; id 9
// c10 => s: 160 diff: +16 11% l 7 cached: 256 40960; id 10
// c11 => s: 176 diff: +16 10% l 7 cached: 256 45056; id 11
// c12 => s: 192 diff: +16 09% l 7 cached: 256 49152; id 12
// c13 => s: 208 diff: +16 08% l 7 cached: 256 53248; id 13
// c14 => s: 224 diff: +16 07% l 7 cached: 256 57344; id 14
// c15 => s: 240 diff: +16 07% l 7 cached: 256 61440; id 15
//
// c16 => s: 256 diff: +16 06% l 8 cached: 256 65536; id 16
// c17 => s: 320 diff: +64 25% l 8 cached: 204 65280; id 17
// c18 => s: 384 diff: +64 20% l 8 cached: 170 65280; id 18
// c19 => s: 448 diff: +64 16% l 8 cached: 146 65408; id 19
//
// c20 => s: 512 diff: +64 14% l 9 cached: 128 65536; id 20
// c21 => s: 640 diff: +128 25% l 9 cached: 102 65280; id 21
// c22 => s: 768 diff: +128 20% l 9 cached: 85 65280; id 22
// c23 => s: 896 diff: +128 16% l 9 cached: 73 65408; id 23
//
// c24 => s: 1024 diff: +128 14% l 10 cached: 64 65536; id 24
// c25 => s: 1280 diff: +256 25% l 10 cached: 51 65280; id 25
// c26 => s: 1536 diff: +256 20% l 10 cached: 42 64512; id 26
// c27 => s: 1792 diff: +256 16% l 10 cached: 36 64512; id 27
//
// ...
//
// c48 => s: 65536 diff: +8192 14% l 16 cached: 1 65536; id 48
// c49 => s: 81920 diff: +16384 25% l 16 cached: 1 81920; id 49
// c50 => s: 98304 diff: +16384 20% l 16 cached: 1 98304; id 50
// c51 => s: 114688 diff: +16384 16% l 16 cached: 1 114688; id 51
//
// c52 => s: 131072 diff: +16384 14% l 17 cached: 1 131072; id 52
template <uptr kMaxSizeLog, uptr kMaxNumCachedT, uptr kMaxBytesCachedLog>
class SizeClassMap {
static const uptr kMinSizeLog = 4;
static const uptr kMidSizeLog = kMinSizeLog + 4;
static const uptr kMinSize = 1 << kMinSizeLog;
static const uptr kMidSize = 1 << kMidSizeLog;
static const uptr kMidClass = kMidSize / kMinSize;
static const uptr S = 2;
static const uptr M = (1 << S) - 1;
public:
static const uptr kMaxNumCached = kMaxNumCachedT;
// We transfer chunks between central and thread-local free lists in batches.
// For small size classes we allocate batches separately.
// For large size classes we use one of the chunks to store the batch.
struct TransferBatch {
TransferBatch *next;
uptr count;
void *batch[kMaxNumCached];
};
static const uptr kMaxSize = 1UL << kMaxSizeLog;
static const uptr kNumClasses =
kMidClass + ((kMaxSizeLog - kMidSizeLog) << S) + 1;
COMPILER_CHECK(kNumClasses >= 32 && kNumClasses <= 256);
static const uptr kNumClassesRounded =
kNumClasses == 32 ? 32 :
kNumClasses <= 64 ? 64 :
kNumClasses <= 128 ? 128 : 256;
static uptr Size(uptr class_id) {
if (class_id <= kMidClass)
return kMinSize * class_id;
class_id -= kMidClass;
uptr t = kMidSize << (class_id >> S);
return t + (t >> S) * (class_id & M);
}
static uptr ClassID(uptr size) {
if (size <= kMidSize)
return (size + kMinSize - 1) >> kMinSizeLog;
if (size > kMaxSize) return 0;
uptr l = MostSignificantSetBitIndex(size);
uptr hbits = (size >> (l - S)) & M;
uptr lbits = size & ((1 << (l - S)) - 1);
uptr l1 = l - kMidSizeLog;
return kMidClass + (l1 << S) + hbits + (lbits > 0);
}
static uptr MaxCached(uptr class_id) {
if (class_id == 0) return 0;
uptr n = (1UL << kMaxBytesCachedLog) / Size(class_id);
return Max<uptr>(1, Min(kMaxNumCached, n));
}
static void Print() {
uptr prev_s = 0;
uptr total_cached = 0;
for (uptr i = 0; i < kNumClasses; i++) {
uptr s = Size(i);
if (s >= kMidSize / 2 && (s & (s - 1)) == 0)
Printf("\n");
uptr d = s - prev_s;
uptr p = prev_s ? (d * 100 / prev_s) : 0;
uptr l = s ? MostSignificantSetBitIndex(s) : 0;
uptr cached = MaxCached(i) * s;
Printf("c%02zd => s: %zd diff: +%zd %02zd%% l %zd "
"cached: %zd %zd; id %zd\n",
i, Size(i), d, p, l, MaxCached(i), cached, ClassID(s));
total_cached += cached;
prev_s = s;
}
Printf("Total cached: %zd\n", total_cached);
}
static bool SizeClassRequiresSeparateTransferBatch(uptr class_id) {
return Size(class_id) < sizeof(TransferBatch) -
sizeof(uptr) * (kMaxNumCached - MaxCached(class_id));
}
static void Validate() {
for (uptr c = 1; c < kNumClasses; c++) {
// Printf("Validate: c%zd\n", c);
uptr s = Size(c);
CHECK_NE(s, 0U);
CHECK_EQ(ClassID(s), c);
if (c != kNumClasses - 1)
CHECK_EQ(ClassID(s + 1), c + 1);
CHECK_EQ(ClassID(s - 1), c);
if (c)
CHECK_GT(Size(c), Size(c-1));
}
CHECK_EQ(ClassID(kMaxSize + 1), 0);
for (uptr s = 1; s <= kMaxSize; s++) {
uptr c = ClassID(s);
// Printf("s%zd => c%zd\n", s, c);
CHECK_LT(c, kNumClasses);
CHECK_GE(Size(c), s);
if (c > 0)
CHECK_LT(Size(c-1), s);
}
}
};
typedef SizeClassMap<17, 128, 16> DefaultSizeClassMap;
typedef SizeClassMap<17, 64, 14> CompactSizeClassMap;
template<class SizeClassAllocator> struct SizeClassAllocatorLocalCache;
// Memory allocator statistics
enum AllocatorStat {
AllocatorStatMalloced,
AllocatorStatFreed,
AllocatorStatMmapped,
AllocatorStatUnmapped,
AllocatorStatCount
};
typedef u64 AllocatorStatCounters[AllocatorStatCount];
// Per-thread stats, live in per-thread cache.
class AllocatorStats {
public:
void Init() {
internal_memset(this, 0, sizeof(*this));
}
void Add(AllocatorStat i, u64 v) {
v += atomic_load(&stats_[i], memory_order_relaxed);
atomic_store(&stats_[i], v, memory_order_relaxed);
}
void Set(AllocatorStat i, u64 v) {
atomic_store(&stats_[i], v, memory_order_relaxed);
}
u64 Get(AllocatorStat i) const {
return atomic_load(&stats_[i], memory_order_relaxed);
}
private:
friend class AllocatorGlobalStats;
AllocatorStats *next_;
AllocatorStats *prev_;
atomic_uint64_t stats_[AllocatorStatCount];
};
// Global stats, used for aggregation and querying.
class AllocatorGlobalStats : public AllocatorStats {
public:
void Init() {
internal_memset(this, 0, sizeof(*this));
next_ = this;
prev_ = this;
}
void Register(AllocatorStats *s) {
SpinMutexLock l(&mu_);
s->next_ = next_;
s->prev_ = this;
next_->prev_ = s;
next_ = s;
}
void Unregister(AllocatorStats *s) {
SpinMutexLock l(&mu_);
s->prev_->next_ = s->next_;
s->next_->prev_ = s->prev_;
for (int i = 0; i < AllocatorStatCount; i++)
Add(AllocatorStat(i), s->Get(AllocatorStat(i)));
}
void Get(AllocatorStatCounters s) const {
internal_memset(s, 0, AllocatorStatCount * sizeof(u64));
SpinMutexLock l(&mu_);
const AllocatorStats *stats = this;
for (;;) {
for (int i = 0; i < AllocatorStatCount; i++)
s[i] += stats->Get(AllocatorStat(i));
stats = stats->next_;
if (stats == this)
break;
}
}
private:
mutable SpinMutex mu_;
};
// Allocators call these callbacks on mmap/munmap.
struct NoOpMapUnmapCallback {
void OnMap(uptr p, uptr size) const { }
void OnUnmap(uptr p, uptr size) const { }
};
// Callback type for iterating over chunks.
typedef void (*ForEachChunkCallback)(uptr chunk, void *arg);
// SizeClassAllocator64 -- allocator for 64-bit address space.
//
// Space: a portion of address space of kSpaceSize bytes starting at
// a fixed address (kSpaceBeg). Both constants are powers of two and
// kSpaceBeg is kSpaceSize-aligned.
// At the beginning the entire space is mprotect-ed, then small parts of it
// are mapped on demand.
//
// Region: a part of Space dedicated to a single size class.
// There are kNumClasses Regions of equal size.
//
// UserChunk: a piece of memory returned to user.
// MetaChunk: kMetadataSize bytes of metadata associated with a UserChunk.
//
// A Region looks like this:
// UserChunk1 ... UserChunkN <gap> MetaChunkN ... MetaChunk1
template <const uptr kSpaceBeg, const uptr kSpaceSize,
const uptr kMetadataSize, class SizeClassMap,
class MapUnmapCallback = NoOpMapUnmapCallback>
class SizeClassAllocator64 {
public:
typedef typename SizeClassMap::TransferBatch Batch;
typedef SizeClassAllocator64<kSpaceBeg, kSpaceSize, kMetadataSize,
SizeClassMap, MapUnmapCallback> ThisT;
typedef SizeClassAllocatorLocalCache<ThisT> AllocatorCache;
void Init() {
CHECK_EQ(kSpaceBeg,
reinterpret_cast<uptr>(Mprotect(kSpaceBeg, kSpaceSize)));
MapWithCallback(kSpaceEnd, AdditionalSize());
}
void MapWithCallback(uptr beg, uptr size) {
CHECK_EQ(beg, reinterpret_cast<uptr>(MmapFixedOrDie(beg, size)));
MapUnmapCallback().OnMap(beg, size);
}
void UnmapWithCallback(uptr beg, uptr size) {
MapUnmapCallback().OnUnmap(beg, size);
UnmapOrDie(reinterpret_cast<void *>(beg), size);
}
static bool CanAllocate(uptr size, uptr alignment) {
return size <= SizeClassMap::kMaxSize &&
alignment <= SizeClassMap::kMaxSize;
}
NOINLINE Batch* AllocateBatch(AllocatorStats *stat, AllocatorCache *c,
uptr class_id) {
CHECK_LT(class_id, kNumClasses);
RegionInfo *region = GetRegionInfo(class_id);
Batch *b = region->free_list.Pop();
if (b == 0)
b = PopulateFreeList(stat, c, class_id, region);
region->n_allocated += b->count;
return b;
}
NOINLINE void DeallocateBatch(AllocatorStats *stat, uptr class_id, Batch *b) {
RegionInfo *region = GetRegionInfo(class_id);
CHECK_GT(b->count, 0);
region->free_list.Push(b);
region->n_freed += b->count;
}
static bool PointerIsMine(const void *p) {
return reinterpret_cast<uptr>(p) / kSpaceSize == kSpaceBeg / kSpaceSize;
}
static uptr GetSizeClass(const void *p) {
return (reinterpret_cast<uptr>(p) / kRegionSize) % kNumClassesRounded;
}
void *GetBlockBegin(const void *p) {
uptr class_id = GetSizeClass(p);
uptr size = SizeClassMap::Size(class_id);
if (!size) return 0;
uptr chunk_idx = GetChunkIdx((uptr)p, size);
uptr reg_beg = (uptr)p & ~(kRegionSize - 1);
uptr beg = chunk_idx * size;
uptr next_beg = beg + size;
if (class_id >= kNumClasses) return 0;
RegionInfo *region = GetRegionInfo(class_id);
if (region->mapped_user >= next_beg)
return reinterpret_cast<void*>(reg_beg + beg);
return 0;
}
static uptr GetActuallyAllocatedSize(void *p) {
CHECK(PointerIsMine(p));
return SizeClassMap::Size(GetSizeClass(p));
}
uptr ClassID(uptr size) { return SizeClassMap::ClassID(size); }
void *GetMetaData(void *p) {
uptr class_id = GetSizeClass(p);
uptr size = SizeClassMap::Size(class_id);
uptr chunk_idx = GetChunkIdx(reinterpret_cast<uptr>(p), size);
return reinterpret_cast<void*>(kSpaceBeg + (kRegionSize * (class_id + 1)) -
(1 + chunk_idx) * kMetadataSize);
}
uptr TotalMemoryUsed() {
uptr res = 0;
for (uptr i = 0; i < kNumClasses; i++)
res += GetRegionInfo(i)->allocated_user;
return res;
}
// Test-only.
void TestOnlyUnmap() {
UnmapWithCallback(kSpaceBeg, kSpaceSize + AdditionalSize());
}
void PrintStats() {
uptr total_mapped = 0;
uptr n_allocated = 0;
uptr n_freed = 0;
for (uptr class_id = 1; class_id < kNumClasses; class_id++) {
RegionInfo *region = GetRegionInfo(class_id);
total_mapped += region->mapped_user;
n_allocated += region->n_allocated;
n_freed += region->n_freed;
}
Printf("Stats: SizeClassAllocator64: %zdM mapped in %zd allocations; "
"remains %zd\n",
total_mapped >> 20, n_allocated, n_allocated - n_freed);
for (uptr class_id = 1; class_id < kNumClasses; class_id++) {
RegionInfo *region = GetRegionInfo(class_id);
if (region->mapped_user == 0) continue;
Printf(" %02zd (%zd): total: %zd K allocs: %zd remains: %zd\n",
class_id,
SizeClassMap::Size(class_id),
region->mapped_user >> 10,
region->n_allocated,
region->n_allocated - region->n_freed);
}
}
// ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone
// introspection API.
void ForceLock() {
for (uptr i = 0; i < kNumClasses; i++) {
GetRegionInfo(i)->mutex.Lock();
}
}
void ForceUnlock() {
for (int i = (int)kNumClasses - 1; i >= 0; i--) {
GetRegionInfo(i)->mutex.Unlock();
}
}
// Iterate over all existing chunks.
// The allocator must be locked when calling this function.
void ForEachChunk(ForEachChunkCallback callback, void *arg) {
for (uptr class_id = 1; class_id < kNumClasses; class_id++) {
RegionInfo *region = GetRegionInfo(class_id);
uptr chunk_size = SizeClassMap::Size(class_id);
uptr region_beg = kSpaceBeg + class_id * kRegionSize;
for (uptr chunk = region_beg;
chunk < region_beg + region->allocated_user;
chunk += chunk_size) {
// Too slow: CHECK_EQ((void *)chunk, GetBlockBegin((void *)chunk));
callback(chunk, arg);
}
}
}
typedef SizeClassMap SizeClassMapT;
static const uptr kNumClasses = SizeClassMap::kNumClasses;
static const uptr kNumClassesRounded = SizeClassMap::kNumClassesRounded;
private:
static const uptr kRegionSize = kSpaceSize / kNumClassesRounded;
static const uptr kSpaceEnd = kSpaceBeg + kSpaceSize;
COMPILER_CHECK(kSpaceBeg % kSpaceSize == 0);
// kRegionSize must be >= 2^32.
COMPILER_CHECK((kRegionSize) >= (1ULL << (SANITIZER_WORDSIZE / 2)));
// Populate the free list with at most this number of bytes at once
// or with one element if its size is greater.
static const uptr kPopulateSize = 1 << 14;
// Call mmap for user memory with at least this size.
static const uptr kUserMapSize = 1 << 16;
// Call mmap for metadata memory with at least this size.
static const uptr kMetaMapSize = 1 << 16;
struct RegionInfo {
BlockingMutex mutex;
LFStack<Batch> free_list;
uptr allocated_user; // Bytes allocated for user memory.
uptr allocated_meta; // Bytes allocated for metadata.
uptr mapped_user; // Bytes mapped for user memory.
uptr mapped_meta; // Bytes mapped for metadata.
uptr n_allocated, n_freed; // Just stats.
};
COMPILER_CHECK(sizeof(RegionInfo) >= kCacheLineSize);
static uptr AdditionalSize() {
return RoundUpTo(sizeof(RegionInfo) * kNumClassesRounded,
GetPageSizeCached());
}
RegionInfo *GetRegionInfo(uptr class_id) {
CHECK_LT(class_id, kNumClasses);
RegionInfo *regions = reinterpret_cast<RegionInfo*>(kSpaceBeg + kSpaceSize);
return &regions[class_id];
}
static uptr GetChunkIdx(uptr chunk, uptr size) {
uptr offset = chunk % kRegionSize;
// Here we divide by a non-constant. This is costly.
// size always fits into 32-bits. If the offset fits too, use 32-bit div.
if (offset >> (SANITIZER_WORDSIZE / 2))
return offset / size;
return (u32)offset / (u32)size;
}
NOINLINE Batch* PopulateFreeList(AllocatorStats *stat, AllocatorCache *c,
uptr class_id, RegionInfo *region) {
BlockingMutexLock l(&region->mutex);
Batch *b = region->free_list.Pop();
if (b)
return b;
uptr size = SizeClassMap::Size(class_id);
uptr count = size < kPopulateSize ? SizeClassMap::MaxCached(class_id) : 1;
uptr beg_idx = region->allocated_user;
uptr end_idx = beg_idx + count * size;
uptr region_beg = kSpaceBeg + kRegionSize * class_id;
if (end_idx + size > region->mapped_user) {
// Do the mmap for the user memory.
uptr map_size = kUserMapSize;
while (end_idx + size > region->mapped_user + map_size)
map_size += kUserMapSize;
CHECK_GE(region->mapped_user + map_size, end_idx);
MapWithCallback(region_beg + region->mapped_user, map_size);
stat->Add(AllocatorStatMmapped, map_size);
region->mapped_user += map_size;
}
uptr total_count = (region->mapped_user - beg_idx - size)
/ size / count * count;
region->allocated_meta += total_count * kMetadataSize;
if (region->allocated_meta > region->mapped_meta) {
uptr map_size = kMetaMapSize;
while (region->allocated_meta > region->mapped_meta + map_size)
map_size += kMetaMapSize;
// Do the mmap for the metadata.
CHECK_GE(region->mapped_meta + map_size, region->allocated_meta);
MapWithCallback(region_beg + kRegionSize -
region->mapped_meta - map_size, map_size);
region->mapped_meta += map_size;
}
CHECK_LE(region->allocated_meta, region->mapped_meta);
if (region->mapped_user + region->mapped_meta > kRegionSize) {
Printf("%s: Out of memory. Dying. ", SanitizerToolName);
Printf("The process has exhausted %zuMB for size class %zu.\n",
kRegionSize / 1024 / 1024, size);
Die();
}
for (;;) {
if (SizeClassMap::SizeClassRequiresSeparateTransferBatch(class_id))
b = (Batch*)c->Allocate(this, SizeClassMap::ClassID(sizeof(Batch)));
else
b = (Batch*)(region_beg + beg_idx);
b->count = count;
for (uptr i = 0; i < count; i++)
b->batch[i] = (void*)(region_beg + beg_idx + i * size);
region->allocated_user += count * size;
CHECK_LE(region->allocated_user, region->mapped_user);
beg_idx += count * size;
if (beg_idx + count * size + size > region->mapped_user)
break;
CHECK_GT(b->count, 0);
region->free_list.Push(b);
}
return b;
}
};
// Maps integers in rage [0, kSize) to u8 values.
template<u64 kSize>
class FlatByteMap {
public:
void TestOnlyInit() {
internal_memset(map_, 0, sizeof(map_));
}
void set(uptr idx, u8 val) {
CHECK_LT(idx, kSize);
CHECK_EQ(0U, map_[idx]);
map_[idx] = val;
}
u8 operator[] (uptr idx) {
CHECK_LT(idx, kSize);
// FIXME: CHECK may be too expensive here.
return map_[idx];
}
private:
u8 map_[kSize];
};
// FIXME: Also implement TwoLevelByteMap.
// SizeClassAllocator32 -- allocator for 32-bit address space.
// This allocator can theoretically be used on 64-bit arch, but there it is less
// efficient than SizeClassAllocator64.
//
// [kSpaceBeg, kSpaceBeg + kSpaceSize) is the range of addresses which can
// be returned by MmapOrDie().
//
// Region:
// a result of a single call to MmapAlignedOrDie(kRegionSize, kRegionSize).
// Since the regions are aligned by kRegionSize, there are exactly
// kNumPossibleRegions possible regions in the address space and so we keep
// a ByteMap possible_regions to store the size classes of each Region.
// 0 size class means the region is not used by the allocator.
//
// One Region is used to allocate chunks of a single size class.
// A Region looks like this:
// UserChunk1 .. UserChunkN <gap> MetaChunkN .. MetaChunk1
//
// In order to avoid false sharing the objects of this class should be
// chache-line aligned.
template <const uptr kSpaceBeg, const u64 kSpaceSize,
const uptr kMetadataSize, class SizeClassMap,
const uptr kRegionSizeLog,
class ByteMap,
class MapUnmapCallback = NoOpMapUnmapCallback>
class SizeClassAllocator32 {
public:
typedef typename SizeClassMap::TransferBatch Batch;
typedef SizeClassAllocator32<kSpaceBeg, kSpaceSize, kMetadataSize,
SizeClassMap, kRegionSizeLog, ByteMap, MapUnmapCallback> ThisT;
typedef SizeClassAllocatorLocalCache<ThisT> AllocatorCache;
void Init() {
possible_regions.TestOnlyInit();
internal_memset(size_class_info_array, 0, sizeof(size_class_info_array));
}
void *MapWithCallback(uptr size) {
size = RoundUpTo(size, GetPageSizeCached());
void *res = MmapOrDie(size, "SizeClassAllocator32");
MapUnmapCallback().OnMap((uptr)res, size);
return res;
}
void UnmapWithCallback(uptr beg, uptr size) {
MapUnmapCallback().OnUnmap(beg, size);
UnmapOrDie(reinterpret_cast<void *>(beg), size);
}
static bool CanAllocate(uptr size, uptr alignment) {
return size <= SizeClassMap::kMaxSize &&
alignment <= SizeClassMap::kMaxSize;
}
void *GetMetaData(void *p) {
CHECK(PointerIsMine(p));
uptr mem = reinterpret_cast<uptr>(p);
uptr beg = ComputeRegionBeg(mem);
uptr size = SizeClassMap::Size(GetSizeClass(p));
u32 offset = mem - beg;
uptr n = offset / (u32)size; // 32-bit division
uptr meta = (beg + kRegionSize) - (n + 1) * kMetadataSize;
return reinterpret_cast<void*>(meta);
}
NOINLINE Batch* AllocateBatch(AllocatorStats *stat, AllocatorCache *c,
uptr class_id) {
CHECK_LT(class_id, kNumClasses);
SizeClassInfo *sci = GetSizeClassInfo(class_id);
SpinMutexLock l(&sci->mutex);
if (sci->free_list.empty())
PopulateFreeList(stat, c, sci, class_id);
CHECK(!sci->free_list.empty());
Batch *b = sci->free_list.front();
sci->free_list.pop_front();
return b;
}
NOINLINE void DeallocateBatch(AllocatorStats *stat, uptr class_id, Batch *b) {
CHECK_LT(class_id, kNumClasses);
SizeClassInfo *sci = GetSizeClassInfo(class_id);
SpinMutexLock l(&sci->mutex);
CHECK_GT(b->count, 0);
sci->free_list.push_front(b);
}
bool PointerIsMine(const void *p) {
return GetSizeClass(p) != 0;
}
uptr GetSizeClass(const void *p) {
return possible_regions[ComputeRegionId(reinterpret_cast<uptr>(p))];
}
void *GetBlockBegin(const void *p) {
CHECK(PointerIsMine(p));
uptr mem = reinterpret_cast<uptr>(p);
uptr beg = ComputeRegionBeg(mem);
uptr size = SizeClassMap::Size(GetSizeClass(p));
u32 offset = mem - beg;
u32 n = offset / (u32)size; // 32-bit division
uptr res = beg + (n * (u32)size);
return reinterpret_cast<void*>(res);
}
uptr GetActuallyAllocatedSize(void *p) {
CHECK(PointerIsMine(p));
return SizeClassMap::Size(GetSizeClass(p));
}
uptr ClassID(uptr size) { return SizeClassMap::ClassID(size); }
uptr TotalMemoryUsed() {
// No need to lock here.
uptr res = 0;
for (uptr i = 0; i < kNumPossibleRegions; i++)
if (possible_regions[i])
res += kRegionSize;
return res;
}
void TestOnlyUnmap() {
for (uptr i = 0; i < kNumPossibleRegions; i++)
if (possible_regions[i])
UnmapWithCallback((i * kRegionSize), kRegionSize);
}
// ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone
// introspection API.
void ForceLock() {
for (uptr i = 0; i < kNumClasses; i++) {
GetSizeClassInfo(i)->mutex.Lock();
}
}
void ForceUnlock() {
for (int i = kNumClasses - 1; i >= 0; i--) {
GetSizeClassInfo(i)->mutex.Unlock();
}
}
// Iterate over all existing chunks.
// The allocator must be locked when calling this function.
void ForEachChunk(ForEachChunkCallback callback, void *arg) {
for (uptr region = 0; region < kNumPossibleRegions; region++)
if (possible_regions[region]) {
uptr chunk_size = SizeClassMap::Size(possible_regions[region]);
uptr max_chunks_in_region = kRegionSize / (chunk_size + kMetadataSize);
uptr region_beg = region * kRegionSize;
for (uptr chunk = region_beg;
chunk < region_beg + max_chunks_in_region * chunk_size;
chunk += chunk_size) {
// Too slow: CHECK_EQ((void *)chunk, GetBlockBegin((void *)chunk));
callback(chunk, arg);
}
}
}
void PrintStats() {
}
typedef SizeClassMap SizeClassMapT;
static const uptr kNumClasses = SizeClassMap::kNumClasses;
private:
static const uptr kRegionSize = 1 << kRegionSizeLog;
static const uptr kNumPossibleRegions = kSpaceSize / kRegionSize;
struct SizeClassInfo {
SpinMutex mutex;
IntrusiveList<Batch> free_list;
char padding[kCacheLineSize - sizeof(uptr) - sizeof(IntrusiveList<Batch>)];
};
COMPILER_CHECK(sizeof(SizeClassInfo) == kCacheLineSize);
uptr ComputeRegionId(uptr mem) {
uptr res = mem >> kRegionSizeLog;
CHECK_LT(res, kNumPossibleRegions);
return res;
}
uptr ComputeRegionBeg(uptr mem) {
return mem & ~(kRegionSize - 1);
}
uptr AllocateRegion(AllocatorStats *stat, uptr class_id) {
CHECK_LT(class_id, kNumClasses);
uptr res = reinterpret_cast<uptr>(MmapAlignedOrDie(kRegionSize, kRegionSize,
"SizeClassAllocator32"));
MapUnmapCallback().OnMap(res, kRegionSize);
stat->Add(AllocatorStatMmapped, kRegionSize);
CHECK_EQ(0U, (res & (kRegionSize - 1)));
possible_regions.set(ComputeRegionId(res), static_cast<u8>(class_id));
return res;
}
SizeClassInfo *GetSizeClassInfo(uptr class_id) {
CHECK_LT(class_id, kNumClasses);
return &size_class_info_array[class_id];
}
void PopulateFreeList(AllocatorStats *stat, AllocatorCache *c,
SizeClassInfo *sci, uptr class_id) {
uptr size = SizeClassMap::Size(class_id);
uptr reg = AllocateRegion(stat, class_id);
uptr n_chunks = kRegionSize / (size + kMetadataSize);
uptr max_count = SizeClassMap::MaxCached(class_id);
Batch *b = 0;
for (uptr i = reg; i < reg + n_chunks * size; i += size) {
if (b == 0) {
if (SizeClassMap::SizeClassRequiresSeparateTransferBatch(class_id))
b = (Batch*)c->Allocate(this, SizeClassMap::ClassID(sizeof(Batch)));
else
b = (Batch*)i;
b->count = 0;
}
b->batch[b->count++] = (void*)i;
if (b->count == max_count) {
CHECK_GT(b->count, 0);
sci->free_list.push_back(b);
b = 0;
}
}
if (b) {
CHECK_GT(b->count, 0);
sci->free_list.push_back(b);
}
}
ByteMap possible_regions;
SizeClassInfo size_class_info_array[kNumClasses];
};
// Objects of this type should be used as local caches for SizeClassAllocator64
// or SizeClassAllocator32. Since the typical use of this class is to have one
// object per thread in TLS, is has to be POD.
template<class SizeClassAllocator>
struct SizeClassAllocatorLocalCache {
typedef SizeClassAllocator Allocator;
static const uptr kNumClasses = SizeClassAllocator::kNumClasses;
void Init(AllocatorGlobalStats *s) {
stats_.Init();
if (s)
s->Register(&stats_);
}
void Destroy(SizeClassAllocator *allocator, AllocatorGlobalStats *s) {
Drain(allocator);
if (s)
s->Unregister(&stats_);
}
void *Allocate(SizeClassAllocator *allocator, uptr class_id) {
CHECK_NE(class_id, 0UL);
CHECK_LT(class_id, kNumClasses);
stats_.Add(AllocatorStatMalloced, SizeClassMap::Size(class_id));
PerClass *c = &per_class_[class_id];
if (UNLIKELY(c->count == 0))
Refill(allocator, class_id);
void *res = c->batch[--c->count];
PREFETCH(c->batch[c->count - 1]);
return res;
}
void Deallocate(SizeClassAllocator *allocator, uptr class_id, void *p) {
CHECK_NE(class_id, 0UL);
CHECK_LT(class_id, kNumClasses);
// If the first allocator call on a new thread is a deallocation, then
// max_count will be zero, leading to check failure.
InitCache();
stats_.Add(AllocatorStatFreed, SizeClassMap::Size(class_id));
PerClass *c = &per_class_[class_id];
CHECK_NE(c->max_count, 0UL);
if (UNLIKELY(c->count == c->max_count))
Drain(allocator, class_id);
c->batch[c->count++] = p;
}
void Drain(SizeClassAllocator *allocator) {
for (uptr class_id = 0; class_id < kNumClasses; class_id++) {
PerClass *c = &per_class_[class_id];
while (c->count > 0)
Drain(allocator, class_id);
}
}
// private:
typedef typename SizeClassAllocator::SizeClassMapT SizeClassMap;
typedef typename SizeClassMap::TransferBatch Batch;
struct PerClass {
uptr count;
uptr max_count;
void *batch[2 * SizeClassMap::kMaxNumCached];
};
PerClass per_class_[kNumClasses];
AllocatorStats stats_;
void InitCache() {
if (per_class_[1].max_count)
return;
for (uptr i = 0; i < kNumClasses; i++) {
PerClass *c = &per_class_[i];
c->max_count = 2 * SizeClassMap::MaxCached(i);
}
}
NOINLINE void Refill(SizeClassAllocator *allocator, uptr class_id) {
InitCache();
PerClass *c = &per_class_[class_id];
Batch *b = allocator->AllocateBatch(&stats_, this, class_id);
CHECK_GT(b->count, 0);
for (uptr i = 0; i < b->count; i++)
c->batch[i] = b->batch[i];
c->count = b->count;
if (SizeClassMap::SizeClassRequiresSeparateTransferBatch(class_id))
Deallocate(allocator, SizeClassMap::ClassID(sizeof(Batch)), b);
}
NOINLINE void Drain(SizeClassAllocator *allocator, uptr class_id) {
InitCache();
PerClass *c = &per_class_[class_id];
Batch *b;
if (SizeClassMap::SizeClassRequiresSeparateTransferBatch(class_id))
b = (Batch*)Allocate(allocator, SizeClassMap::ClassID(sizeof(Batch)));
else
b = (Batch*)c->batch[0];
uptr cnt = Min(c->max_count / 2, c->count);
for (uptr i = 0; i < cnt; i++) {
b->batch[i] = c->batch[i];
c->batch[i] = c->batch[i + c->max_count / 2];
}
b->count = cnt;
c->count -= cnt;
CHECK_GT(b->count, 0);
allocator->DeallocateBatch(&stats_, class_id, b);
}
};
// This class can (de)allocate only large chunks of memory using mmap/unmap.
// The main purpose of this allocator is to cover large and rare allocation
// sizes not covered by more efficient allocators (e.g. SizeClassAllocator64).
template <class MapUnmapCallback = NoOpMapUnmapCallback>
class LargeMmapAllocator {
public:
void Init() {
internal_memset(this, 0, sizeof(*this));
page_size_ = GetPageSizeCached();
}
void *Allocate(AllocatorStats *stat, uptr size, uptr alignment) {
CHECK(IsPowerOfTwo(alignment));
uptr map_size = RoundUpMapSize(size);
if (alignment > page_size_)
map_size += alignment;
if (map_size < size) return 0; // Overflow.
uptr map_beg = reinterpret_cast<uptr>(
MmapOrDie(map_size, "LargeMmapAllocator"));
MapUnmapCallback().OnMap(map_beg, map_size);
uptr map_end = map_beg + map_size;
uptr res = map_beg + page_size_;
if (res & (alignment - 1)) // Align.
res += alignment - (res & (alignment - 1));
CHECK_EQ(0, res & (alignment - 1));
CHECK_LE(res + size, map_end);
Header *h = GetHeader(res);
h->size = size;
h->map_beg = map_beg;
h->map_size = map_size;
uptr size_log = MostSignificantSetBitIndex(map_size);
CHECK_LT(size_log, ARRAY_SIZE(stats.by_size_log));
{
SpinMutexLock l(&mutex_);
uptr idx = n_chunks_++;
chunks_sorted_ = false;
CHECK_LT(idx, kMaxNumChunks);
h->chunk_idx = idx;
chunks_[idx] = h;
stats.n_allocs++;
stats.currently_allocated += map_size;
stats.max_allocated = Max(stats.max_allocated, stats.currently_allocated);
stats.by_size_log[size_log]++;
stat->Add(AllocatorStatMalloced, map_size);
stat->Add(AllocatorStatMmapped, map_size);
}
return reinterpret_cast<void*>(res);
}
void Deallocate(AllocatorStats *stat, void *p) {
Header *h = GetHeader(p);
{
SpinMutexLock l(&mutex_);
uptr idx = h->chunk_idx;
CHECK_EQ(chunks_[idx], h);
CHECK_LT(idx, n_chunks_);
chunks_[idx] = chunks_[n_chunks_ - 1];
chunks_[idx]->chunk_idx = idx;
n_chunks_--;
chunks_sorted_ = false;
stats.n_frees++;
stats.currently_allocated -= h->map_size;
stat->Add(AllocatorStatFreed, h->map_size);
stat->Add(AllocatorStatUnmapped, h->map_size);
}
MapUnmapCallback().OnUnmap(h->map_beg, h->map_size);
UnmapOrDie(reinterpret_cast<void*>(h->map_beg), h->map_size);
}
uptr TotalMemoryUsed() {
SpinMutexLock l(&mutex_);
uptr res = 0;
for (uptr i = 0; i < n_chunks_; i++) {
Header *h = chunks_[i];
CHECK_EQ(h->chunk_idx, i);
res += RoundUpMapSize(h->size);
}
return res;
}
bool PointerIsMine(const void *p) {
return GetBlockBegin(p) != 0;
}
uptr GetActuallyAllocatedSize(void *p) {
return RoundUpTo(GetHeader(p)->size, page_size_);
}
// At least page_size_/2 metadata bytes is available.
void *GetMetaData(void *p) {
// Too slow: CHECK_EQ(p, GetBlockBegin(p));
CHECK(IsAligned(reinterpret_cast<uptr>(p), page_size_));
return GetHeader(p) + 1;
}
void *GetBlockBegin(const void *ptr) {
uptr p = reinterpret_cast<uptr>(ptr);
SpinMutexLock l(&mutex_);
uptr nearest_chunk = 0;
// Cache-friendly linear search.
for (uptr i = 0; i < n_chunks_; i++) {
uptr ch = reinterpret_cast<uptr>(chunks_[i]);
if (p < ch) continue; // p is at left to this chunk, skip it.
if (p - ch < p - nearest_chunk)
nearest_chunk = ch;
}
if (!nearest_chunk)
return 0;
Header *h = reinterpret_cast<Header *>(nearest_chunk);
CHECK_GE(nearest_chunk, h->map_beg);
CHECK_LT(nearest_chunk, h->map_beg + h->map_size);
CHECK_LE(nearest_chunk, p);
if (h->map_beg + h->map_size <= p)
return 0;
return GetUser(h);
}
// This function does the same as GetBlockBegin, but is much faster.
// Must be called with the allocator locked.
void *GetBlockBeginFastLocked(void *ptr) {
uptr p = reinterpret_cast<uptr>(ptr);
uptr n = n_chunks_;
if (!n) return 0;
if (!chunks_sorted_) {
// Do one-time sort. chunks_sorted_ is reset in Allocate/Deallocate.
SortArray(reinterpret_cast<uptr*>(chunks_), n);
for (uptr i = 0; i < n; i++)
chunks_[i]->chunk_idx = i;
chunks_sorted_ = true;
min_mmap_ = reinterpret_cast<uptr>(chunks_[0]);
max_mmap_ = reinterpret_cast<uptr>(chunks_[n - 1]) +
chunks_[n - 1]->map_size;
}
if (p < min_mmap_ || p >= max_mmap_)
return 0;
uptr beg = 0, end = n - 1;
// This loop is a log(n) lower_bound. It does not check for the exact match
// to avoid expensive cache-thrashing loads.
while (end - beg >= 2) {
uptr mid = (beg + end) / 2; // Invariant: mid >= beg + 1
if (p < reinterpret_cast<uptr>(chunks_[mid]))
end = mid - 1; // We are not interested in chunks_[mid].
else
beg = mid; // chunks_[mid] may still be what we want.
}
if (beg < end) {
CHECK_EQ(beg + 1, end);
// There are 2 chunks left, choose one.
if (p >= reinterpret_cast<uptr>(chunks_[end]))
beg = end;
}
Header *h = chunks_[beg];
if (h->map_beg + h->map_size <= p || p < h->map_beg)
return 0;
return GetUser(h);
}
void PrintStats() {
Printf("Stats: LargeMmapAllocator: allocated %zd times, "
"remains %zd (%zd K) max %zd M; by size logs: ",
stats.n_allocs, stats.n_allocs - stats.n_frees,
stats.currently_allocated >> 10, stats.max_allocated >> 20);
for (uptr i = 0; i < ARRAY_SIZE(stats.by_size_log); i++) {
uptr c = stats.by_size_log[i];
if (!c) continue;
Printf("%zd:%zd; ", i, c);
}
Printf("\n");
}
// ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone
// introspection API.
void ForceLock() {
mutex_.Lock();
}
void ForceUnlock() {
mutex_.Unlock();
}
// Iterate over all existing chunks.
// The allocator must be locked when calling this function.
void ForEachChunk(ForEachChunkCallback callback, void *arg) {
for (uptr i = 0; i < n_chunks_; i++)
callback(reinterpret_cast<uptr>(GetUser(chunks_[i])), arg);
}
private:
static const int kMaxNumChunks = 1 << FIRST_32_SECOND_64(15, 18);
struct Header {
uptr map_beg;
uptr map_size;
uptr size;
uptr chunk_idx;
};
Header *GetHeader(uptr p) {
CHECK(IsAligned(p, page_size_));
return reinterpret_cast<Header*>(p - page_size_);
}
Header *GetHeader(void *p) { return GetHeader(reinterpret_cast<uptr>(p)); }
void *GetUser(Header *h) {
CHECK(IsAligned((uptr)h, page_size_));
return reinterpret_cast<void*>(reinterpret_cast<uptr>(h) + page_size_);
}
uptr RoundUpMapSize(uptr size) {
return RoundUpTo(size, page_size_) + page_size_;
}
uptr page_size_;
Header *chunks_[kMaxNumChunks];
uptr n_chunks_;
uptr min_mmap_, max_mmap_;
bool chunks_sorted_;
struct Stats {
uptr n_allocs, n_frees, currently_allocated, max_allocated, by_size_log[64];
} stats;
SpinMutex mutex_;
};
// This class implements a complete memory allocator by using two
// internal allocators:
// PrimaryAllocator is efficient, but may not allocate some sizes (alignments).
// When allocating 2^x bytes it should return 2^x aligned chunk.
// PrimaryAllocator is used via a local AllocatorCache.
// SecondaryAllocator can allocate anything, but is not efficient.
template <class PrimaryAllocator, class AllocatorCache,
class SecondaryAllocator> // NOLINT
class CombinedAllocator {
public:
void Init() {
primary_.Init();
secondary_.Init();
stats_.Init();
}
void *Allocate(AllocatorCache *cache, uptr size, uptr alignment,
bool cleared = false) {
// Returning 0 on malloc(0) may break a lot of code.
if (size == 0)
size = 1;
if (size + alignment < size)
return 0;
if (alignment > 8)
size = RoundUpTo(size, alignment);
void *res;
if (primary_.CanAllocate(size, alignment))
res = cache->Allocate(&primary_, primary_.ClassID(size));
else
res = secondary_.Allocate(&stats_, size, alignment);
if (alignment > 8)
CHECK_EQ(reinterpret_cast<uptr>(res) & (alignment - 1), 0);
if (cleared && res)
internal_memset(res, 0, size);
return res;
}
void Deallocate(AllocatorCache *cache, void *p) {
if (!p) return;
if (primary_.PointerIsMine(p))
cache->Deallocate(&primary_, primary_.GetSizeClass(p), p);
else
secondary_.Deallocate(&stats_, p);
}
void *Reallocate(AllocatorCache *cache, void *p, uptr new_size,
uptr alignment) {
if (!p)
return Allocate(cache, new_size, alignment);
if (!new_size) {
Deallocate(cache, p);
return 0;
}
CHECK(PointerIsMine(p));
uptr old_size = GetActuallyAllocatedSize(p);
uptr memcpy_size = Min(new_size, old_size);
void *new_p = Allocate(cache, new_size, alignment);
if (new_p)
internal_memcpy(new_p, p, memcpy_size);
Deallocate(cache, p);
return new_p;
}
bool PointerIsMine(void *p) {
if (primary_.PointerIsMine(p))
return true;
return secondary_.PointerIsMine(p);
}
bool FromPrimary(void *p) {
return primary_.PointerIsMine(p);
}
void *GetMetaData(void *p) {
if (primary_.PointerIsMine(p))
return primary_.GetMetaData(p);
return secondary_.GetMetaData(p);
}
void *GetBlockBegin(const void *p) {
if (primary_.PointerIsMine(p))
return primary_.GetBlockBegin(p);
return secondary_.GetBlockBegin(p);
}
// This function does the same as GetBlockBegin, but is much faster.
// Must be called with the allocator locked.
void *GetBlockBeginFastLocked(void *p) {
if (primary_.PointerIsMine(p))
return primary_.GetBlockBegin(p);
return secondary_.GetBlockBeginFastLocked(p);
}
uptr GetActuallyAllocatedSize(void *p) {
if (primary_.PointerIsMine(p))
return primary_.GetActuallyAllocatedSize(p);
return secondary_.GetActuallyAllocatedSize(p);
}
uptr TotalMemoryUsed() {
return primary_.TotalMemoryUsed() + secondary_.TotalMemoryUsed();
}
void TestOnlyUnmap() { primary_.TestOnlyUnmap(); }
void InitCache(AllocatorCache *cache) {
cache->Init(&stats_);
}
void DestroyCache(AllocatorCache *cache) {
cache->Destroy(&primary_, &stats_);
}
void SwallowCache(AllocatorCache *cache) {
cache->Drain(&primary_);
}
void GetStats(AllocatorStatCounters s) const {
stats_.Get(s);
}
void PrintStats() {
primary_.PrintStats();
secondary_.PrintStats();
}
// ForceLock() and ForceUnlock() are needed to implement Darwin malloc zone
// introspection API.
void ForceLock() {
primary_.ForceLock();
secondary_.ForceLock();
}
void ForceUnlock() {
secondary_.ForceUnlock();
primary_.ForceUnlock();
}
// Iterate over all existing chunks.
// The allocator must be locked when calling this function.
void ForEachChunk(ForEachChunkCallback callback, void *arg) {
primary_.ForEachChunk(callback, arg);
secondary_.ForEachChunk(callback, arg);
}
private:
PrimaryAllocator primary_;
SecondaryAllocator secondary_;
AllocatorGlobalStats stats_;
};
// Returns true if calloc(size, n) should return 0 due to overflow in size*n.
bool CallocShouldReturnNullDueToOverflow(uptr size, uptr n);
} // namespace __sanitizer
#endif // SANITIZER_ALLOCATOR_H
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