1 //===-- sanitizer_quarantine.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 // Memory quarantine for AddressSanitizer and potentially other tools. 9 // Quarantine caches some specified amount of memory in per-thread caches, 10 // then evicts to global FIFO queue. When the queue reaches specified threshold, 11 // oldest memory is recycled. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef SANITIZER_QUARANTINE_H 16 #define SANITIZER_QUARANTINE_H 17 18 #include "sanitizer_internal_defs.h" 19 #include "sanitizer_mutex.h" 20 #include "sanitizer_list.h" 21 22 namespace __sanitizer { 23 24 template<typename Node> class QuarantineCache; 25 26 struct QuarantineBatch { 27 static const uptr kSize = 1021; 28 QuarantineBatch *next; 29 uptr size; 30 uptr count; 31 void *batch[kSize]; 32 }; 33 34 COMPILER_CHECK(sizeof(QuarantineBatch) <= (1 << 13)); // 8Kb. 35 36 // The callback interface is: 37 // void Callback::Recycle(Node *ptr); 38 // void *cb.Allocate(uptr size); 39 // void cb.Deallocate(void *ptr); 40 template<typename Callback, typename Node> 41 class Quarantine { 42 public: 43 typedef QuarantineCache<Callback> Cache; 44 45 explicit Quarantine(LinkerInitialized) 46 : cache_(LINKER_INITIALIZED) { 47 } 48 49 void Init(uptr size, uptr cache_size) { 50 max_size_ = size; 51 min_size_ = size / 10 * 9; // 90% of max size. 52 max_cache_size_ = cache_size; 53 } 54 55 void Put(Cache *c, Callback cb, Node *ptr, uptr size) { 56 c->Enqueue(cb, ptr, size); 57 if (c->Size() > max_cache_size_) 58 Drain(c, cb); 59 } 60 61 void NOINLINE Drain(Cache *c, Callback cb) { 62 { 63 SpinMutexLock l(&cache_mutex_); 64 cache_.Transfer(c); 65 } 66 if (cache_.Size() > max_size_ && recycle_mutex_.TryLock()) 67 Recycle(cb); 68 } 69 70 private: 71 // Read-only data. 72 char pad0_[kCacheLineSize]; 73 uptr max_size_; 74 uptr min_size_; 75 uptr max_cache_size_; 76 char pad1_[kCacheLineSize]; 77 SpinMutex cache_mutex_; 78 SpinMutex recycle_mutex_; 79 Cache cache_; 80 char pad2_[kCacheLineSize]; 81 82 void NOINLINE Recycle(Callback cb) { 83 Cache tmp; 84 { 85 SpinMutexLock l(&cache_mutex_); 86 while (cache_.Size() > min_size_) { 87 QuarantineBatch *b = cache_.DequeueBatch(); 88 tmp.EnqueueBatch(b); 89 } 90 } 91 recycle_mutex_.Unlock(); 92 DoRecycle(&tmp, cb); 93 } 94 95 void NOINLINE DoRecycle(Cache *c, Callback cb) { 96 while (QuarantineBatch *b = c->DequeueBatch()) { 97 const uptr kPrefetch = 16; 98 for (uptr i = 0; i < kPrefetch; i++) 99 PREFETCH(b->batch[i]); 100 for (uptr i = 0; i < b->count; i++) { 101 PREFETCH(b->batch[i + kPrefetch]); 102 cb.Recycle((Node*)b->batch[i]); 103 } 104 cb.Deallocate(b); 105 } 106 } 107 }; 108 109 // Per-thread cache of memory blocks. 110 template<typename Callback> 111 class QuarantineCache { 112 public: 113 explicit QuarantineCache(LinkerInitialized) { 114 } 115 116 QuarantineCache() 117 : size_() { 118 list_.clear(); 119 } 120 121 uptr Size() const { 122 return atomic_load(&size_, memory_order_relaxed); 123 } 124 125 void Enqueue(Callback cb, void *ptr, uptr size) { 126 if (list_.empty() || list_.back()->count == QuarantineBatch::kSize) { 127 AllocBatch(cb); 128 size += sizeof(QuarantineBatch); // Count the batch in Quarantine size. 129 } 130 QuarantineBatch *b = list_.back(); 131 b->batch[b->count++] = ptr; 132 b->size += size; 133 SizeAdd(size); 134 } 135 136 void Transfer(QuarantineCache *c) { 137 list_.append_back(&c->list_); 138 SizeAdd(c->Size()); 139 atomic_store(&c->size_, 0, memory_order_relaxed); 140 } 141 142 void EnqueueBatch(QuarantineBatch *b) { 143 list_.push_back(b); 144 SizeAdd(b->size); 145 } 146 147 QuarantineBatch *DequeueBatch() { 148 if (list_.empty()) 149 return 0; 150 QuarantineBatch *b = list_.front(); 151 list_.pop_front(); 152 SizeSub(b->size); 153 return b; 154 } 155 156 private: 157 IntrusiveList<QuarantineBatch> list_; 158 atomic_uintptr_t size_; 159 160 void SizeAdd(uptr add) { 161 atomic_store(&size_, Size() + add, memory_order_relaxed); 162 } 163 void SizeSub(uptr sub) { 164 atomic_store(&size_, Size() - sub, memory_order_relaxed); 165 } 166 167 NOINLINE QuarantineBatch* AllocBatch(Callback cb) { 168 QuarantineBatch *b = (QuarantineBatch *)cb.Allocate(sizeof(*b)); 169 b->count = 0; 170 b->size = 0; 171 list_.push_back(b); 172 return b; 173 } 174 }; 175 } // namespace __sanitizer 176 177 #endif // #ifndef SANITIZER_QUARANTINE_H 178