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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ART_RUNTIME_GC_ALLOCATION_RECORD_H_
     18 #define ART_RUNTIME_GC_ALLOCATION_RECORD_H_
     19 
     20 #include <list>
     21 #include <memory>
     22 
     23 #include "base/mutex.h"
     24 #include "gc_root.h"
     25 #include "obj_ptr.h"
     26 
     27 namespace art {
     28 
     29 class ArtMethod;
     30 class IsMarkedVisitor;
     31 class Thread;
     32 
     33 namespace mirror {
     34 class Class;
     35 class Object;
     36 }  // namespace mirror
     37 
     38 namespace gc {
     39 
     40 class AllocRecordStackTraceElement {
     41  public:
     42   int32_t ComputeLineNumber() const REQUIRES_SHARED(Locks::mutator_lock_);
     43 
     44   AllocRecordStackTraceElement() = default;
     45   AllocRecordStackTraceElement(ArtMethod* method, uint32_t dex_pc)
     46       : method_(method),
     47         dex_pc_(dex_pc) {}
     48 
     49   ArtMethod* GetMethod() const {
     50     return method_;
     51   }
     52 
     53   void SetMethod(ArtMethod* m) {
     54     method_ = m;
     55   }
     56 
     57   uint32_t GetDexPc() const {
     58     return dex_pc_;
     59   }
     60 
     61   void SetDexPc(uint32_t pc) {
     62     dex_pc_ = pc;
     63   }
     64 
     65   bool operator==(const AllocRecordStackTraceElement& other) const {
     66     return method_ == other.method_ && dex_pc_ == other.dex_pc_;
     67   }
     68 
     69  private:
     70   ArtMethod* method_ = nullptr;
     71   uint32_t dex_pc_ = 0;
     72 };
     73 
     74 class AllocRecordStackTrace {
     75  public:
     76   static constexpr size_t kHashMultiplier = 17;
     77 
     78   AllocRecordStackTrace() = default;
     79 
     80   AllocRecordStackTrace(AllocRecordStackTrace&& r)
     81       : tid_(r.tid_),
     82         stack_(std::move(r.stack_)) {}
     83 
     84   AllocRecordStackTrace(const AllocRecordStackTrace& r)
     85       : tid_(r.tid_),
     86         stack_(r.stack_) {}
     87 
     88   pid_t GetTid() const {
     89     return tid_;
     90   }
     91 
     92   void SetTid(pid_t t) {
     93     tid_ = t;
     94   }
     95 
     96   size_t GetDepth() const {
     97     return stack_.size();
     98   }
     99 
    100   const AllocRecordStackTraceElement& GetStackElement(size_t index) const {
    101     DCHECK_LT(index, GetDepth());
    102     return stack_[index];
    103   }
    104 
    105   void AddStackElement(const AllocRecordStackTraceElement& element) {
    106     stack_.push_back(element);
    107   }
    108 
    109   void SetStackElementAt(size_t index, ArtMethod* m, uint32_t dex_pc) {
    110     DCHECK_LT(index, stack_.size());
    111     stack_[index].SetMethod(m);
    112     stack_[index].SetDexPc(dex_pc);
    113   }
    114 
    115   bool operator==(const AllocRecordStackTrace& other) const {
    116     if (this == &other) return true;
    117     return tid_ == other.tid_ && stack_ == other.stack_;
    118   }
    119 
    120  private:
    121   pid_t tid_ = 0;
    122   std::vector<AllocRecordStackTraceElement> stack_;
    123 };
    124 
    125 struct HashAllocRecordTypes {
    126   size_t operator()(const AllocRecordStackTraceElement& r) const {
    127     return std::hash<void*>()(reinterpret_cast<void*>(r.GetMethod())) *
    128         AllocRecordStackTrace::kHashMultiplier + std::hash<uint32_t>()(r.GetDexPc());
    129   }
    130 
    131   size_t operator()(const AllocRecordStackTrace& r) const {
    132     size_t depth = r.GetDepth();
    133     size_t result = r.GetTid() * AllocRecordStackTrace::kHashMultiplier + depth;
    134     for (size_t i = 0; i < depth; ++i) {
    135       result = result * AllocRecordStackTrace::kHashMultiplier + (*this)(r.GetStackElement(i));
    136     }
    137     return result;
    138   }
    139 };
    140 
    141 template <typename T> struct HashAllocRecordTypesPtr {
    142   size_t operator()(const T* r) const {
    143     if (r == nullptr) return 0;
    144     return HashAllocRecordTypes()(*r);
    145   }
    146 };
    147 
    148 template <typename T> struct EqAllocRecordTypesPtr {
    149   bool operator()(const T* r1, const T* r2) const {
    150     if (r1 == r2) return true;
    151     if (r1 == nullptr || r2 == nullptr) return false;
    152     return *r1 == *r2;
    153   }
    154 };
    155 
    156 class AllocRecord {
    157  public:
    158   // All instances of AllocRecord should be managed by an instance of AllocRecordObjectMap.
    159   AllocRecord(size_t count, mirror::Class* klass, AllocRecordStackTrace&& trace)
    160       : byte_count_(count), klass_(klass), trace_(std::move(trace)) {}
    161 
    162   size_t GetDepth() const {
    163     return trace_.GetDepth();
    164   }
    165 
    166   const AllocRecordStackTrace* GetStackTrace() const {
    167     return &trace_;
    168   }
    169 
    170   size_t ByteCount() const {
    171     return byte_count_;
    172   }
    173 
    174   pid_t GetTid() const {
    175     return trace_.GetTid();
    176   }
    177 
    178   mirror::Class* GetClass() const REQUIRES_SHARED(Locks::mutator_lock_) {
    179     return klass_.Read();
    180   }
    181 
    182   const char* GetClassDescriptor(std::string* storage) const
    183       REQUIRES_SHARED(Locks::mutator_lock_);
    184 
    185   GcRoot<mirror::Class>& GetClassGcRoot() REQUIRES_SHARED(Locks::mutator_lock_) {
    186     return klass_;
    187   }
    188 
    189   const AllocRecordStackTraceElement& StackElement(size_t index) const {
    190     return trace_.GetStackElement(index);
    191   }
    192 
    193  private:
    194   const size_t byte_count_;
    195   // The klass_ could be a strong or weak root for GC
    196   GcRoot<mirror::Class> klass_;
    197   // TODO: Share between alloc records with identical stack traces.
    198   AllocRecordStackTrace trace_;
    199 };
    200 
    201 class AllocRecordObjectMap {
    202  public:
    203   static constexpr size_t kDefaultNumAllocRecords = 512 * 1024;
    204   static constexpr size_t kDefaultNumRecentRecords = 64 * 1024 - 1;
    205   static constexpr size_t kDefaultAllocStackDepth = 16;
    206   static constexpr size_t kMaxSupportedStackDepth = 128;
    207 
    208   // GcRoot<mirror::Object> pointers in the list are weak roots, and the last recent_record_max_
    209   // number of AllocRecord::klass_ pointers are strong roots (and the rest of klass_ pointers are
    210   // weak roots). The last recent_record_max_ number of pairs in the list are always kept for DDMS's
    211   // recent allocation tracking, but GcRoot<mirror::Object> pointers in these pairs can become null.
    212   // Both types of pointers need read barriers, do not directly access them.
    213   using EntryPair = std::pair<GcRoot<mirror::Object>, AllocRecord>;
    214   typedef std::list<EntryPair> EntryList;
    215 
    216   // Caller needs to check that it is enabled before calling since we read the stack trace before
    217   // checking the enabled boolean.
    218   void RecordAllocation(Thread* self,
    219                         ObjPtr<mirror::Object>* obj,
    220                         size_t byte_count)
    221       REQUIRES(!Locks::alloc_tracker_lock_)
    222       REQUIRES_SHARED(Locks::mutator_lock_);
    223 
    224   static void SetAllocTrackingEnabled(bool enabled) REQUIRES(!Locks::alloc_tracker_lock_);
    225 
    226   AllocRecordObjectMap() REQUIRES(Locks::alloc_tracker_lock_);
    227   ~AllocRecordObjectMap();
    228 
    229   void Put(mirror::Object* obj, AllocRecord&& record)
    230       REQUIRES_SHARED(Locks::mutator_lock_)
    231       REQUIRES(Locks::alloc_tracker_lock_) {
    232     if (entries_.size() == alloc_record_max_) {
    233       entries_.pop_front();
    234     }
    235     entries_.push_back(EntryPair(GcRoot<mirror::Object>(obj), std::move(record)));
    236   }
    237 
    238   size_t Size() const REQUIRES_SHARED(Locks::alloc_tracker_lock_) {
    239     return entries_.size();
    240   }
    241 
    242   size_t GetRecentAllocationSize() const REQUIRES_SHARED(Locks::alloc_tracker_lock_) {
    243     CHECK_LE(recent_record_max_, alloc_record_max_);
    244     size_t sz = entries_.size();
    245     return std::min(recent_record_max_, sz);
    246   }
    247 
    248   void VisitRoots(RootVisitor* visitor)
    249       REQUIRES_SHARED(Locks::mutator_lock_)
    250       REQUIRES(Locks::alloc_tracker_lock_);
    251 
    252   void SweepAllocationRecords(IsMarkedVisitor* visitor)
    253       REQUIRES_SHARED(Locks::mutator_lock_)
    254       REQUIRES(Locks::alloc_tracker_lock_);
    255 
    256   // Allocation tracking could be enabled by user in between DisallowNewAllocationRecords() and
    257   // AllowNewAllocationRecords(), in which case new allocation records can be added although they
    258   // should be disallowed. However, this is GC-safe because new objects are not processed in this GC
    259   // cycle. The only downside of not handling this case is that such new allocation records can be
    260   // swept from the list. But missing the first few records is acceptable for using the button to
    261   // enable allocation tracking.
    262   void DisallowNewAllocationRecords()
    263       REQUIRES_SHARED(Locks::mutator_lock_)
    264       REQUIRES(Locks::alloc_tracker_lock_);
    265   void AllowNewAllocationRecords()
    266       REQUIRES_SHARED(Locks::mutator_lock_)
    267       REQUIRES(Locks::alloc_tracker_lock_);
    268   void BroadcastForNewAllocationRecords()
    269       REQUIRES(Locks::alloc_tracker_lock_);
    270 
    271   // TODO: Is there a better way to hide the entries_'s type?
    272   EntryList::iterator Begin()
    273       REQUIRES_SHARED(Locks::mutator_lock_)
    274       REQUIRES(Locks::alloc_tracker_lock_) {
    275     return entries_.begin();
    276   }
    277 
    278   EntryList::iterator End()
    279       REQUIRES_SHARED(Locks::mutator_lock_)
    280       REQUIRES(Locks::alloc_tracker_lock_) {
    281     return entries_.end();
    282   }
    283 
    284   EntryList::reverse_iterator RBegin()
    285       REQUIRES_SHARED(Locks::mutator_lock_)
    286       REQUIRES(Locks::alloc_tracker_lock_) {
    287     return entries_.rbegin();
    288   }
    289 
    290   EntryList::reverse_iterator REnd()
    291       REQUIRES_SHARED(Locks::mutator_lock_)
    292       REQUIRES(Locks::alloc_tracker_lock_) {
    293     return entries_.rend();
    294   }
    295 
    296   void Clear() REQUIRES(Locks::alloc_tracker_lock_);
    297 
    298  private:
    299   size_t alloc_record_max_ GUARDED_BY(Locks::alloc_tracker_lock_) = kDefaultNumAllocRecords;
    300   size_t recent_record_max_ GUARDED_BY(Locks::alloc_tracker_lock_) = kDefaultNumRecentRecords;
    301   size_t max_stack_depth_ = kDefaultAllocStackDepth;
    302   pid_t alloc_ddm_thread_id_  GUARDED_BY(Locks::alloc_tracker_lock_) = 0;
    303   bool allow_new_record_ GUARDED_BY(Locks::alloc_tracker_lock_) = true;
    304   ConditionVariable new_record_condition_ GUARDED_BY(Locks::alloc_tracker_lock_);
    305   // see the comment in typedef of EntryList
    306   EntryList entries_ GUARDED_BY(Locks::alloc_tracker_lock_);
    307 
    308   void SetMaxStackDepth(size_t max_stack_depth) REQUIRES(Locks::alloc_tracker_lock_);
    309 };
    310 
    311 }  // namespace gc
    312 }  // namespace art
    313 #endif  // ART_RUNTIME_GC_ALLOCATION_RECORD_H_
    314