1//===-- sanitizer_quarantine.h ----------------------------------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// Memory quarantine for AddressSanitizer and potentially other tools. 11// Quarantine caches some specified amount of memory in per-thread caches, 12// then evicts to global FIFO queue. When the queue reaches specified threshold, 13// oldest memory is recycled. 14// 15//===----------------------------------------------------------------------===// 16 17#ifndef SANITIZER_QUARANTINE_H 18#define SANITIZER_QUARANTINE_H 19 20#include "sanitizer_internal_defs.h" 21#include "sanitizer_mutex.h" 22#include "sanitizer_list.h" 23 24namespace __sanitizer { 25 26template<typename Node> class QuarantineCache; 27 28struct QuarantineBatch { 29 static const uptr kSize = 1021; 30 QuarantineBatch *next; 31 uptr size; 32 uptr count; 33 void *batch[kSize]; 34}; 35 36COMPILER_CHECK(sizeof(QuarantineBatch) <= (1 << 13)); // 8Kb. 37 38// The callback interface is: 39// void Callback::Recycle(Node *ptr); 40// void *cb.Allocate(uptr size); 41// void cb.Deallocate(void *ptr); 42template<typename Callback, typename Node> 43class Quarantine { 44 public: 45 typedef QuarantineCache<Callback> Cache; 46 47 explicit Quarantine(LinkerInitialized) 48 : cache_(LINKER_INITIALIZED) { 49 } 50 51 void Init(uptr size, uptr cache_size) { 52 atomic_store(&max_size_, size, memory_order_release); 53 atomic_store(&min_size_, size / 10 * 9, 54 memory_order_release); // 90% of max size. 55 max_cache_size_ = cache_size; 56 } 57 58 uptr GetSize() const { return atomic_load(&max_size_, memory_order_acquire); } 59 60 void Put(Cache *c, Callback cb, Node *ptr, uptr size) { 61 c->Enqueue(cb, ptr, size); 62 if (c->Size() > max_cache_size_) 63 Drain(c, cb); 64 } 65 66 void NOINLINE Drain(Cache *c, Callback cb) { 67 { 68 SpinMutexLock l(&cache_mutex_); 69 cache_.Transfer(c); 70 } 71 if (cache_.Size() > GetSize() && recycle_mutex_.TryLock()) 72 Recycle(cb); 73 } 74 75 private: 76 // Read-only data. 77 char pad0_[kCacheLineSize]; 78 atomic_uintptr_t max_size_; 79 atomic_uintptr_t min_size_; 80 uptr max_cache_size_; 81 char pad1_[kCacheLineSize]; 82 SpinMutex cache_mutex_; 83 SpinMutex recycle_mutex_; 84 Cache cache_; 85 char pad2_[kCacheLineSize]; 86 87 void NOINLINE Recycle(Callback cb) { 88 Cache tmp; 89 uptr min_size = atomic_load(&min_size_, memory_order_acquire); 90 { 91 SpinMutexLock l(&cache_mutex_); 92 while (cache_.Size() > min_size) { 93 QuarantineBatch *b = cache_.DequeueBatch(); 94 tmp.EnqueueBatch(b); 95 } 96 } 97 recycle_mutex_.Unlock(); 98 DoRecycle(&tmp, cb); 99 } 100 101 void NOINLINE DoRecycle(Cache *c, Callback cb) { 102 while (QuarantineBatch *b = c->DequeueBatch()) { 103 const uptr kPrefetch = 16; 104 for (uptr i = 0; i < kPrefetch; i++) 105 PREFETCH(b->batch[i]); 106 for (uptr i = 0; i < b->count; i++) { 107 PREFETCH(b->batch[i + kPrefetch]); 108 cb.Recycle((Node*)b->batch[i]); 109 } 110 cb.Deallocate(b); 111 } 112 } 113}; 114 115// Per-thread cache of memory blocks. 116template<typename Callback> 117class QuarantineCache { 118 public: 119 explicit QuarantineCache(LinkerInitialized) { 120 } 121 122 QuarantineCache() 123 : size_() { 124 list_.clear(); 125 } 126 127 uptr Size() const { 128 return atomic_load(&size_, memory_order_relaxed); 129 } 130 131 void Enqueue(Callback cb, void *ptr, uptr size) { 132 if (list_.empty() || list_.back()->count == QuarantineBatch::kSize) { 133 AllocBatch(cb); 134 size += sizeof(QuarantineBatch); // Count the batch in Quarantine size. 135 } 136 QuarantineBatch *b = list_.back(); 137 CHECK(b); 138 b->batch[b->count++] = ptr; 139 b->size += size; 140 SizeAdd(size); 141 } 142 143 void Transfer(QuarantineCache *c) { 144 list_.append_back(&c->list_); 145 SizeAdd(c->Size()); 146 atomic_store(&c->size_, 0, memory_order_relaxed); 147 } 148 149 void EnqueueBatch(QuarantineBatch *b) { 150 list_.push_back(b); 151 SizeAdd(b->size); 152 } 153 154 QuarantineBatch *DequeueBatch() { 155 if (list_.empty()) 156 return 0; 157 QuarantineBatch *b = list_.front(); 158 list_.pop_front(); 159 SizeSub(b->size); 160 return b; 161 } 162 163 private: 164 IntrusiveList<QuarantineBatch> list_; 165 atomic_uintptr_t size_; 166 167 void SizeAdd(uptr add) { 168 atomic_store(&size_, Size() + add, memory_order_relaxed); 169 } 170 void SizeSub(uptr sub) { 171 atomic_store(&size_, Size() - sub, memory_order_relaxed); 172 } 173 174 NOINLINE QuarantineBatch* AllocBatch(Callback cb) { 175 QuarantineBatch *b = (QuarantineBatch *)cb.Allocate(sizeof(*b)); 176 CHECK(b); 177 b->count = 0; 178 b->size = 0; 179 list_.push_back(b); 180 return b; 181 } 182}; 183} // namespace __sanitizer 184 185#endif // #ifndef SANITIZER_QUARANTINE_H 186