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/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ART_RUNTIME_GC_ALLOCATION_RECORD_H_
#define ART_RUNTIME_GC_ALLOCATION_RECORD_H_
#include <list>
#include "base/mutex.h"
#include "object_callbacks.h"
#include "gc_root.h"
namespace art {
class ArtMethod;
class Thread;
namespace mirror {
class Class;
class Object;
}
namespace gc {
class AllocRecordStackTraceElement {
public:
AllocRecordStackTraceElement() : method_(nullptr), dex_pc_(0) {}
int32_t ComputeLineNumber() const SHARED_REQUIRES(Locks::mutator_lock_);
ArtMethod* GetMethod() const {
return method_;
}
void SetMethod(ArtMethod* m) {
method_ = m;
}
uint32_t GetDexPc() const {
return dex_pc_;
}
void SetDexPc(uint32_t pc) {
dex_pc_ = pc;
}
bool operator==(const AllocRecordStackTraceElement& other) const {
if (this == &other) return true;
return method_ == other.method_ && dex_pc_ == other.dex_pc_;
}
private:
ArtMethod* method_;
uint32_t dex_pc_;
};
class AllocRecordStackTrace {
public:
static constexpr size_t kHashMultiplier = 17;
explicit AllocRecordStackTrace(size_t max_depth)
: tid_(0), depth_(0), stack_(new AllocRecordStackTraceElement[max_depth]) {}
AllocRecordStackTrace(const AllocRecordStackTrace& r)
: tid_(r.tid_), depth_(r.depth_), stack_(new AllocRecordStackTraceElement[r.depth_]) {
for (size_t i = 0; i < depth_; ++i) {
stack_[i] = r.stack_[i];
}
}
~AllocRecordStackTrace() {
delete[] stack_;
}
pid_t GetTid() const {
return tid_;
}
void SetTid(pid_t t) {
tid_ = t;
}
size_t GetDepth() const {
return depth_;
}
void SetDepth(size_t depth) {
depth_ = depth;
}
const AllocRecordStackTraceElement& GetStackElement(size_t index) const {
DCHECK_LT(index, depth_);
return stack_[index];
}
void SetStackElementAt(size_t index, ArtMethod* m, uint32_t dex_pc) {
stack_[index].SetMethod(m);
stack_[index].SetDexPc(dex_pc);
}
bool operator==(const AllocRecordStackTrace& other) const {
if (this == &other) return true;
if (tid_ != other.tid_) return false;
if (depth_ != other.depth_) return false;
for (size_t i = 0; i < depth_; ++i) {
if (!(stack_[i] == other.stack_[i])) return false;
}
return true;
}
private:
pid_t tid_;
size_t depth_;
AllocRecordStackTraceElement* const stack_;
};
struct HashAllocRecordTypes {
size_t operator()(const AllocRecordStackTraceElement& r) const {
return std::hash<void*>()(reinterpret_cast<void*>(r.GetMethod())) *
AllocRecordStackTrace::kHashMultiplier + std::hash<uint32_t>()(r.GetDexPc());
}
size_t operator()(const AllocRecordStackTrace& r) const {
size_t depth = r.GetDepth();
size_t result = r.GetTid() * AllocRecordStackTrace::kHashMultiplier + depth;
for (size_t i = 0; i < depth; ++i) {
result = result * AllocRecordStackTrace::kHashMultiplier + (*this)(r.GetStackElement(i));
}
return result;
}
};
template <typename T> struct HashAllocRecordTypesPtr {
size_t operator()(const T* r) const {
if (r == nullptr) return 0;
return HashAllocRecordTypes()(*r);
}
};
template <typename T> struct EqAllocRecordTypesPtr {
bool operator()(const T* r1, const T* r2) const {
if (r1 == r2) return true;
if (r1 == nullptr || r2 == nullptr) return false;
return *r1 == *r2;
}
};
class AllocRecord {
public:
// All instances of AllocRecord should be managed by an instance of AllocRecordObjectMap.
AllocRecord(size_t count, mirror::Class* klass, AllocRecordStackTrace* trace)
: byte_count_(count), klass_(klass), trace_(trace) {}
~AllocRecord() {
delete trace_;
}
size_t GetDepth() const {
return trace_->GetDepth();
}
const AllocRecordStackTrace* GetStackTrace() const {
return trace_;
}
size_t ByteCount() const {
return byte_count_;
}
pid_t GetTid() const {
return trace_->GetTid();
}
mirror::Class* GetClass() const SHARED_REQUIRES(Locks::mutator_lock_) {
return klass_.Read();
}
const char* GetClassDescriptor(std::string* storage) const
SHARED_REQUIRES(Locks::mutator_lock_);
GcRoot<mirror::Class>& GetClassGcRoot() SHARED_REQUIRES(Locks::mutator_lock_) {
return klass_;
}
const AllocRecordStackTraceElement& StackElement(size_t index) const {
return trace_->GetStackElement(index);
}
private:
const size_t byte_count_;
// The klass_ could be a strong or weak root for GC
GcRoot<mirror::Class> klass_;
// TODO: Currently trace_ is like a std::unique_ptr,
// but in future with deduplication it could be a std::shared_ptr.
const AllocRecordStackTrace* const trace_;
};
class AllocRecordObjectMap {
public:
// GcRoot<mirror::Object> pointers in the list are weak roots, and the last recent_record_max_
// number of AllocRecord::klass_ pointers are strong roots (and the rest of klass_ pointers are
// weak roots). The last recent_record_max_ number of pairs in the list are always kept for DDMS's
// recent allocation tracking, but GcRoot<mirror::Object> pointers in these pairs can become null.
// Both types of pointers need read barriers, do not directly access them.
typedef std::list<std::pair<GcRoot<mirror::Object>, AllocRecord*>> EntryList;
// "static" because it is part of double-checked locking. It needs to check a bool first,
// in order to make sure the AllocRecordObjectMap object is not null.
static void RecordAllocation(Thread* self, mirror::Object* obj, mirror::Class* klass,
size_t byte_count)
REQUIRES(!Locks::alloc_tracker_lock_)
SHARED_REQUIRES(Locks::mutator_lock_);
static void SetAllocTrackingEnabled(bool enabled) REQUIRES(!Locks::alloc_tracker_lock_);
AllocRecordObjectMap() REQUIRES(Locks::alloc_tracker_lock_)
: alloc_record_max_(kDefaultNumAllocRecords),
recent_record_max_(kDefaultNumRecentRecords),
max_stack_depth_(kDefaultAllocStackDepth),
scratch_trace_(kMaxSupportedStackDepth),
alloc_ddm_thread_id_(0),
allow_new_record_(true),
new_record_condition_("New allocation record condition", *Locks::alloc_tracker_lock_) {}
~AllocRecordObjectMap();
void Put(mirror::Object* obj, AllocRecord* record)
SHARED_REQUIRES(Locks::mutator_lock_)
REQUIRES(Locks::alloc_tracker_lock_) {
if (entries_.size() == alloc_record_max_) {
delete entries_.front().second;
entries_.pop_front();
}
entries_.emplace_back(GcRoot<mirror::Object>(obj), record);
}
size_t Size() const SHARED_REQUIRES(Locks::alloc_tracker_lock_) {
return entries_.size();
}
size_t GetRecentAllocationSize() const SHARED_REQUIRES(Locks::alloc_tracker_lock_) {
CHECK_LE(recent_record_max_, alloc_record_max_);
size_t sz = entries_.size();
return std::min(recent_record_max_, sz);
}
void VisitRoots(RootVisitor* visitor)
SHARED_REQUIRES(Locks::mutator_lock_)
REQUIRES(Locks::alloc_tracker_lock_);
void SweepAllocationRecords(IsMarkedVisitor* visitor)
SHARED_REQUIRES(Locks::mutator_lock_)
REQUIRES(Locks::alloc_tracker_lock_);
// Allocation tracking could be enabled by user in between DisallowNewAllocationRecords() and
// AllowNewAllocationRecords(), in which case new allocation records can be added although they
// should be disallowed. However, this is GC-safe because new objects are not processed in this GC
// cycle. The only downside of not handling this case is that such new allocation records can be
// swept from the list. But missing the first few records is acceptable for using the button to
// enable allocation tracking.
void DisallowNewAllocationRecords()
SHARED_REQUIRES(Locks::mutator_lock_)
REQUIRES(Locks::alloc_tracker_lock_);
void AllowNewAllocationRecords()
SHARED_REQUIRES(Locks::mutator_lock_)
REQUIRES(Locks::alloc_tracker_lock_);
// TODO: Is there a better way to hide the entries_'s type?
EntryList::iterator Begin()
SHARED_REQUIRES(Locks::mutator_lock_)
REQUIRES(Locks::alloc_tracker_lock_) {
return entries_.begin();
}
EntryList::iterator End()
SHARED_REQUIRES(Locks::mutator_lock_)
REQUIRES(Locks::alloc_tracker_lock_) {
return entries_.end();
}
EntryList::reverse_iterator RBegin()
SHARED_REQUIRES(Locks::mutator_lock_)
REQUIRES(Locks::alloc_tracker_lock_) {
return entries_.rbegin();
}
EntryList::reverse_iterator REnd()
SHARED_REQUIRES(Locks::mutator_lock_)
REQUIRES(Locks::alloc_tracker_lock_) {
return entries_.rend();
}
private:
static constexpr size_t kDefaultNumAllocRecords = 512 * 1024;
static constexpr size_t kDefaultNumRecentRecords = 64 * 1024 - 1;
static constexpr size_t kDefaultAllocStackDepth = 16;
static constexpr size_t kMaxSupportedStackDepth = 128;
size_t alloc_record_max_ GUARDED_BY(Locks::alloc_tracker_lock_);
size_t recent_record_max_ GUARDED_BY(Locks::alloc_tracker_lock_);
size_t max_stack_depth_ GUARDED_BY(Locks::alloc_tracker_lock_);
AllocRecordStackTrace scratch_trace_ GUARDED_BY(Locks::alloc_tracker_lock_);
pid_t alloc_ddm_thread_id_ GUARDED_BY(Locks::alloc_tracker_lock_);
bool allow_new_record_ GUARDED_BY(Locks::alloc_tracker_lock_);
ConditionVariable new_record_condition_ GUARDED_BY(Locks::alloc_tracker_lock_);
// see the comment in typedef of EntryList
EntryList entries_ GUARDED_BY(Locks::alloc_tracker_lock_);
void SetProperties() REQUIRES(Locks::alloc_tracker_lock_);
};
} // namespace gc
} // namespace art
#endif // ART_RUNTIME_GC_ALLOCATION_RECORD_H_