More of the concurrent copying collector.
Bug: 12687968
Change-Id: I62f70274d47df6d6cab714df95c518b750ce3105
diff --git a/runtime/gc/collector/concurrent_copying.cc b/runtime/gc/collector/concurrent_copying.cc
index 079eeba..5fa3c8b 100644
--- a/runtime/gc/collector/concurrent_copying.cc
+++ b/runtime/gc/collector/concurrent_copying.cc
@@ -16,10 +16,1627 @@
#include "concurrent_copying.h"
+#include "gc/accounting/heap_bitmap-inl.h"
+#include "gc/accounting/space_bitmap-inl.h"
+#include "gc/space/image_space.h"
+#include "gc/space/space.h"
+#include "intern_table.h"
+#include "mirror/art_field-inl.h"
+#include "mirror/object-inl.h"
+#include "scoped_thread_state_change.h"
+#include "thread-inl.h"
+#include "thread_list.h"
+#include "well_known_classes.h"
+
namespace art {
namespace gc {
namespace collector {
+ConcurrentCopying::ConcurrentCopying(Heap* heap, const std::string& name_prefix)
+ : GarbageCollector(heap,
+ name_prefix + (name_prefix.empty() ? "" : " ") +
+ "concurrent copying + mark sweep"),
+ region_space_(nullptr), gc_barrier_(new Barrier(0)), mark_queue_(2 * MB),
+ is_marking_(false), is_active_(false), is_asserting_to_space_invariant_(false),
+ heap_mark_bitmap_(nullptr), live_stack_freeze_size_(0),
+ skipped_blocks_lock_("concurrent copying bytes blocks lock", kMarkSweepMarkStackLock),
+ rb_table_(heap_->GetReadBarrierTable()),
+ force_evacuate_all_(false) {
+ static_assert(space::RegionSpace::kRegionSize == accounting::ReadBarrierTable::kRegionSize,
+ "The region space size and the read barrier table region size must match");
+ cc_heap_bitmap_.reset(new accounting::HeapBitmap(heap));
+ {
+ Thread* self = Thread::Current();
+ ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_);
+ // Cache this so that we won't have to lock heap_bitmap_lock_ in
+ // Mark() which could cause a nested lock on heap_bitmap_lock_
+ // when GC causes a RB while doing GC or a lock order violation
+ // (class_linker_lock_ and heap_bitmap_lock_).
+ heap_mark_bitmap_ = heap->GetMarkBitmap();
+ }
+}
+
+ConcurrentCopying::~ConcurrentCopying() {
+}
+
+void ConcurrentCopying::RunPhases() {
+ CHECK(kUseBakerReadBarrier || kUseTableLookupReadBarrier);
+ CHECK(!is_active_);
+ is_active_ = true;
+ Thread* self = Thread::Current();
+ Locks::mutator_lock_->AssertNotHeld(self);
+ {
+ ReaderMutexLock mu(self, *Locks::mutator_lock_);
+ InitializePhase();
+ }
+ FlipThreadRoots();
+ {
+ ReaderMutexLock mu(self, *Locks::mutator_lock_);
+ MarkingPhase();
+ }
+ // Verify no from space refs. This causes a pause.
+ if (kEnableNoFromSpaceRefsVerification || kIsDebugBuild) {
+ TimingLogger::ScopedTiming split("(Paused)VerifyNoFromSpaceReferences", GetTimings());
+ ScopedPause pause(this);
+ CheckEmptyMarkQueue();
+ if (kVerboseMode) {
+ LOG(INFO) << "Verifying no from-space refs";
+ }
+ VerifyNoFromSpaceReferences();
+ CheckEmptyMarkQueue();
+ }
+ {
+ ReaderMutexLock mu(self, *Locks::mutator_lock_);
+ ReclaimPhase();
+ }
+ FinishPhase();
+ CHECK(is_active_);
+ is_active_ = false;
+}
+
+void ConcurrentCopying::BindBitmaps() {
+ Thread* self = Thread::Current();
+ WriterMutexLock mu(self, *Locks::heap_bitmap_lock_);
+ // Mark all of the spaces we never collect as immune.
+ for (const auto& space : heap_->GetContinuousSpaces()) {
+ if (space->GetGcRetentionPolicy() == space::kGcRetentionPolicyNeverCollect
+ || space->GetGcRetentionPolicy() == space::kGcRetentionPolicyFullCollect) {
+ CHECK(space->IsZygoteSpace() || space->IsImageSpace());
+ CHECK(immune_region_.AddContinuousSpace(space)) << "Failed to add space " << *space;
+ const char* bitmap_name = space->IsImageSpace() ? "cc image space bitmap" :
+ "cc zygote space bitmap";
+ // TODO: try avoiding using bitmaps for image/zygote to save space.
+ accounting::ContinuousSpaceBitmap* bitmap =
+ accounting::ContinuousSpaceBitmap::Create(bitmap_name, space->Begin(), space->Capacity());
+ cc_heap_bitmap_->AddContinuousSpaceBitmap(bitmap);
+ cc_bitmaps_.push_back(bitmap);
+ } else if (space == region_space_) {
+ accounting::ContinuousSpaceBitmap* bitmap =
+ accounting::ContinuousSpaceBitmap::Create("cc region space bitmap",
+ space->Begin(), space->Capacity());
+ cc_heap_bitmap_->AddContinuousSpaceBitmap(bitmap);
+ cc_bitmaps_.push_back(bitmap);
+ region_space_bitmap_ = bitmap;
+ }
+ }
+}
+
+void ConcurrentCopying::InitializePhase() {
+ TimingLogger::ScopedTiming split("InitializePhase", GetTimings());
+ if (kVerboseMode) {
+ LOG(INFO) << "GC InitializePhase";
+ LOG(INFO) << "Region-space : " << reinterpret_cast<void*>(region_space_->Begin()) << "-"
+ << reinterpret_cast<void*>(region_space_->Limit());
+ }
+ CHECK(mark_queue_.IsEmpty());
+ immune_region_.Reset();
+ bytes_moved_.StoreRelaxed(0);
+ objects_moved_.StoreRelaxed(0);
+ if (GetCurrentIteration()->GetGcCause() == kGcCauseExplicit ||
+ GetCurrentIteration()->GetGcCause() == kGcCauseForNativeAlloc ||
+ GetCurrentIteration()->GetClearSoftReferences()) {
+ force_evacuate_all_ = true;
+ } else {
+ force_evacuate_all_ = false;
+ }
+ BindBitmaps();
+ if (kVerboseMode) {
+ LOG(INFO) << "force_evacuate_all=" << force_evacuate_all_;
+ LOG(INFO) << "Immune region: " << immune_region_.Begin() << "-" << immune_region_.End();
+ LOG(INFO) << "GC end of InitializePhase";
+ }
+}
+
+// Used to switch the thread roots of a thread from from-space refs to to-space refs.
+class ThreadFlipVisitor : public Closure {
+ public:
+ explicit ThreadFlipVisitor(ConcurrentCopying* concurrent_copying, bool use_tlab)
+ : concurrent_copying_(concurrent_copying), use_tlab_(use_tlab) {
+ }
+
+ virtual void Run(Thread* thread) OVERRIDE SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ // Note: self is not necessarily equal to thread since thread may be suspended.
+ Thread* self = Thread::Current();
+ CHECK(thread == self || thread->IsSuspended() || thread->GetState() == kWaitingPerformingGc)
+ << thread->GetState() << " thread " << thread << " self " << self;
+ if (use_tlab_ && thread->HasTlab()) {
+ if (ConcurrentCopying::kEnableFromSpaceAccountingCheck) {
+ // This must come before the revoke.
+ size_t thread_local_objects = thread->GetThreadLocalObjectsAllocated();
+ concurrent_copying_->region_space_->RevokeThreadLocalBuffers(thread);
+ reinterpret_cast<Atomic<size_t>*>(&concurrent_copying_->from_space_num_objects_at_first_pause_)->
+ FetchAndAddSequentiallyConsistent(thread_local_objects);
+ } else {
+ concurrent_copying_->region_space_->RevokeThreadLocalBuffers(thread);
+ }
+ }
+ if (kUseThreadLocalAllocationStack) {
+ thread->RevokeThreadLocalAllocationStack();
+ }
+ ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_);
+ thread->VisitRoots(ConcurrentCopying::ProcessRootCallback, concurrent_copying_);
+ concurrent_copying_->GetBarrier().Pass(self);
+ }
+
+ private:
+ ConcurrentCopying* const concurrent_copying_;
+ const bool use_tlab_;
+};
+
+// Called back from Runtime::FlipThreadRoots() during a pause.
+class FlipCallback : public Closure {
+ public:
+ explicit FlipCallback(ConcurrentCopying* concurrent_copying)
+ : concurrent_copying_(concurrent_copying) {
+ }
+
+ virtual void Run(Thread* thread) OVERRIDE EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ ConcurrentCopying* cc = concurrent_copying_;
+ TimingLogger::ScopedTiming split("(Paused)FlipCallback", cc->GetTimings());
+ // Note: self is not necessarily equal to thread since thread may be suspended.
+ Thread* self = Thread::Current();
+ CHECK(thread == self);
+ Locks::mutator_lock_->AssertExclusiveHeld(self);
+ cc->region_space_->SetFromSpace(cc->rb_table_, cc->force_evacuate_all_);
+ cc->SwapStacks(self);
+ if (ConcurrentCopying::kEnableFromSpaceAccountingCheck) {
+ cc->RecordLiveStackFreezeSize(self);
+ cc->from_space_num_objects_at_first_pause_ = cc->region_space_->GetObjectsAllocated();
+ cc->from_space_num_bytes_at_first_pause_ = cc->region_space_->GetBytesAllocated();
+ }
+ cc->is_marking_ = true;
+ if (UNLIKELY(Runtime::Current()->IsActiveTransaction())) {
+ CHECK(Runtime::Current()->IsCompiler());
+ TimingLogger::ScopedTiming split2("(Paused)VisitTransactionRoots", cc->GetTimings());
+ Runtime::Current()->VisitTransactionRoots(ConcurrentCopying::ProcessRootCallback, cc);
+ }
+ }
+
+ private:
+ ConcurrentCopying* const concurrent_copying_;
+};
+
+// Switch threads that from from-space to to-space refs. Forward/mark the thread roots.
+void ConcurrentCopying::FlipThreadRoots() {
+ TimingLogger::ScopedTiming split("FlipThreadRoots", GetTimings());
+ if (kVerboseMode) {
+ LOG(INFO) << "time=" << region_space_->Time();
+ region_space_->DumpNonFreeRegions(LOG(INFO));
+ }
+ Thread* self = Thread::Current();
+ Locks::mutator_lock_->AssertNotHeld(self);
+ gc_barrier_->Init(self, 0);
+ ThreadFlipVisitor thread_flip_visitor(this, heap_->use_tlab_);
+ FlipCallback flip_callback(this);
+ size_t barrier_count = Runtime::Current()->FlipThreadRoots(
+ &thread_flip_visitor, &flip_callback, this);
+ {
+ ScopedThreadStateChange tsc(self, kWaitingForCheckPointsToRun);
+ gc_barrier_->Increment(self, barrier_count);
+ }
+ is_asserting_to_space_invariant_ = true;
+ QuasiAtomic::ThreadFenceForConstructor();
+ if (kVerboseMode) {
+ LOG(INFO) << "time=" << region_space_->Time();
+ region_space_->DumpNonFreeRegions(LOG(INFO));
+ LOG(INFO) << "GC end of FlipThreadRoots";
+ }
+}
+
+void ConcurrentCopying::SwapStacks(Thread* self) {
+ heap_->SwapStacks(self);
+}
+
+void ConcurrentCopying::RecordLiveStackFreezeSize(Thread* self) {
+ WriterMutexLock mu(self, *Locks::heap_bitmap_lock_);
+ live_stack_freeze_size_ = heap_->GetLiveStack()->Size();
+}
+
+// Used to visit objects in the immune spaces.
+class ConcurrentCopyingImmuneSpaceObjVisitor {
+ public:
+ explicit ConcurrentCopyingImmuneSpaceObjVisitor(ConcurrentCopying* cc)
+ : collector_(cc) {}
+
+ void operator()(mirror::Object* obj) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
+ SHARED_LOCKS_REQUIRED(Locks::heap_bitmap_lock_) {
+ DCHECK(obj != nullptr);
+ DCHECK(collector_->immune_region_.ContainsObject(obj));
+ accounting::ContinuousSpaceBitmap* cc_bitmap =
+ collector_->cc_heap_bitmap_->GetContinuousSpaceBitmap(obj);
+ DCHECK(cc_bitmap != nullptr)
+ << "An immune space object must have a bitmap";
+ if (kIsDebugBuild) {
+ DCHECK(collector_->heap_->GetMarkBitmap()->Test(obj))
+ << "Immune space object must be already marked";
+ }
+ // This may or may not succeed, which is ok.
+ if (kUseBakerReadBarrier) {
+ obj->AtomicSetReadBarrierPointer(ReadBarrier::WhitePtr(), ReadBarrier::GrayPtr());
+ }
+ if (cc_bitmap->AtomicTestAndSet(obj)) {
+ // Already marked. Do nothing.
+ } else {
+ // Newly marked. Set the gray bit and push it onto the mark stack.
+ CHECK(!kUseBakerReadBarrier || obj->GetReadBarrierPointer() == ReadBarrier::GrayPtr());
+ collector_->PushOntoMarkStack<true>(obj);
+ }
+ }
+
+ private:
+ ConcurrentCopying* collector_;
+};
+
+class EmptyCheckpoint : public Closure {
+ public:
+ explicit EmptyCheckpoint(ConcurrentCopying* concurrent_copying)
+ : concurrent_copying_(concurrent_copying) {
+ }
+
+ virtual void Run(Thread* thread) OVERRIDE NO_THREAD_SAFETY_ANALYSIS {
+ // Note: self is not necessarily equal to thread since thread may be suspended.
+ Thread* self = Thread::Current();
+ CHECK(thread == self || thread->IsSuspended() || thread->GetState() == kWaitingPerformingGc)
+ << thread->GetState() << " thread " << thread << " self " << self;
+ concurrent_copying_->GetBarrier().Pass(self);
+ }
+
+ private:
+ ConcurrentCopying* const concurrent_copying_;
+};
+
+// Concurrently mark roots that are guarded by read barriers and process the mark stack.
+void ConcurrentCopying::MarkingPhase() {
+ TimingLogger::ScopedTiming split("MarkingPhase", GetTimings());
+ if (kVerboseMode) {
+ LOG(INFO) << "GC MarkingPhase";
+ }
+ {
+ // Mark the image root. The WB-based collectors do not need to
+ // scan the image objects from roots by relying on the card table,
+ // but it's necessary for the RB to-space invariant to hold.
+ TimingLogger::ScopedTiming split1("VisitImageRoots", GetTimings());
+ gc::space::ImageSpace* image = heap_->GetImageSpace();
+ if (image != nullptr) {
+ mirror::ObjectArray<mirror::Object>* image_root = image->GetImageHeader().GetImageRoots();
+ mirror::Object* marked_image_root = Mark(image_root);
+ CHECK_EQ(image_root, marked_image_root) << "An image object does not move";
+ if (ReadBarrier::kEnableToSpaceInvariantChecks) {
+ AssertToSpaceInvariant(nullptr, MemberOffset(0), marked_image_root);
+ }
+ }
+ }
+ {
+ TimingLogger::ScopedTiming split2("VisitConstantRoots", GetTimings());
+ Runtime::Current()->VisitConstantRoots(ProcessRootCallback, this);
+ }
+ {
+ TimingLogger::ScopedTiming split3("VisitInternTableRoots", GetTimings());
+ Runtime::Current()->GetInternTable()->VisitRoots(ProcessRootCallback,
+ this, kVisitRootFlagAllRoots);
+ }
+ {
+ TimingLogger::ScopedTiming split4("VisitClassLinkerRoots", GetTimings());
+ Runtime::Current()->GetClassLinker()->VisitRoots(ProcessRootCallback,
+ this, kVisitRootFlagAllRoots);
+ }
+ {
+ // TODO: don't visit the transaction roots if it's not active.
+ TimingLogger::ScopedTiming split5("VisitNonThreadRoots", GetTimings());
+ Runtime::Current()->VisitNonThreadRoots(ProcessRootCallback, this);
+ }
+
+ // Immune spaces.
+ for (auto& space : heap_->GetContinuousSpaces()) {
+ if (immune_region_.ContainsSpace(space)) {
+ DCHECK(space->IsImageSpace() || space->IsZygoteSpace());
+ accounting::ContinuousSpaceBitmap* live_bitmap = space->GetLiveBitmap();
+ ConcurrentCopyingImmuneSpaceObjVisitor visitor(this);
+ live_bitmap->VisitMarkedRange(reinterpret_cast<uintptr_t>(space->Begin()),
+ reinterpret_cast<uintptr_t>(space->Limit()),
+ visitor);
+ }
+ }
+
+ Thread* self = Thread::Current();
+ {
+ TimingLogger::ScopedTiming split6("ProcessMarkStack", GetTimings());
+ // Process the mark stack and issue an empty check point. If the
+ // mark stack is still empty after the check point, we're
+ // done. Otherwise, repeat.
+ ProcessMarkStack();
+ size_t count = 0;
+ while (!ProcessMarkStack()) {
+ ++count;
+ if (kVerboseMode) {
+ LOG(INFO) << "Issue an empty check point. " << count;
+ }
+ IssueEmptyCheckpoint();
+ }
+ // Need to ensure the mark stack is empty before reference
+ // processing to get rid of non-reference gray objects.
+ CheckEmptyMarkQueue();
+ // Enable the GetReference slow path and disallow access to the system weaks.
+ GetHeap()->GetReferenceProcessor()->EnableSlowPath();
+ Runtime::Current()->DisallowNewSystemWeaks();
+ QuasiAtomic::ThreadFenceForConstructor();
+ // Lock-unlock the system weak locks so that there's no thread in
+ // the middle of accessing system weaks.
+ Runtime::Current()->EnsureNewSystemWeaksDisallowed();
+ // Note: Do not issue a checkpoint from here to the
+ // SweepSystemWeaks call or else a deadlock due to
+ // WaitHoldingLocks() would occur.
+ if (kVerboseMode) {
+ LOG(INFO) << "Enabled the ref proc slow path & disabled access to system weaks.";
+ LOG(INFO) << "ProcessReferences";
+ }
+ ProcessReferences(self, true);
+ CheckEmptyMarkQueue();
+ if (kVerboseMode) {
+ LOG(INFO) << "SweepSystemWeaks";
+ }
+ SweepSystemWeaks(self);
+ if (kVerboseMode) {
+ LOG(INFO) << "SweepSystemWeaks done";
+ }
+ // Because hash_set::Erase() can call the hash function for
+ // arbitrary elements in the weak intern table in
+ // InternTable::Table::SweepWeaks(), the above SweepSystemWeaks()
+ // call may have marked some objects (strings) alive. So process
+ // the mark stack here once again.
+ ProcessMarkStack();
+ CheckEmptyMarkQueue();
+ // Disable marking.
+ if (kUseTableLookupReadBarrier) {
+ heap_->rb_table_->ClearAll();
+ DCHECK(heap_->rb_table_->IsAllCleared());
+ }
+ is_mark_queue_push_disallowed_.StoreSequentiallyConsistent(1);
+ is_marking_ = false;
+ if (kVerboseMode) {
+ LOG(INFO) << "AllowNewSystemWeaks";
+ }
+ Runtime::Current()->AllowNewSystemWeaks();
+ CheckEmptyMarkQueue();
+ }
+
+ if (kVerboseMode) {
+ LOG(INFO) << "GC end of MarkingPhase";
+ }
+}
+
+void ConcurrentCopying::IssueEmptyCheckpoint() {
+ Thread* self = Thread::Current();
+ EmptyCheckpoint check_point(this);
+ ThreadList* thread_list = Runtime::Current()->GetThreadList();
+ gc_barrier_->Init(self, 0);
+ size_t barrier_count = thread_list->RunCheckpoint(&check_point);
+ // Release locks then wait for all mutator threads to pass the barrier.
+ Locks::mutator_lock_->SharedUnlock(self);
+ {
+ ScopedThreadStateChange tsc(self, kWaitingForCheckPointsToRun);
+ gc_barrier_->Increment(self, barrier_count);
+ }
+ Locks::mutator_lock_->SharedLock(self);
+}
+
+mirror::Object* ConcurrentCopying::PopOffMarkStack() {
+ return mark_queue_.Dequeue();
+}
+
+template<bool kThreadSafe>
+void ConcurrentCopying::PushOntoMarkStack(mirror::Object* to_ref) {
+ CHECK_EQ(is_mark_queue_push_disallowed_.LoadRelaxed(), 0)
+ << " " << to_ref << " " << PrettyTypeOf(to_ref);
+ if (kThreadSafe) {
+ CHECK(mark_queue_.Enqueue(to_ref)) << "Mark queue overflow";
+ } else {
+ CHECK(mark_queue_.EnqueueThreadUnsafe(to_ref)) << "Mark queue overflow";
+ }
+}
+
+accounting::ObjectStack* ConcurrentCopying::GetAllocationStack() {
+ return heap_->allocation_stack_.get();
+}
+
+accounting::ObjectStack* ConcurrentCopying::GetLiveStack() {
+ return heap_->live_stack_.get();
+}
+
+inline mirror::Object* ConcurrentCopying::GetFwdPtr(mirror::Object* from_ref) {
+ DCHECK(region_space_->IsInFromSpace(from_ref));
+ LockWord lw = from_ref->GetLockWord(false);
+ if (lw.GetState() == LockWord::kForwardingAddress) {
+ mirror::Object* fwd_ptr = reinterpret_cast<mirror::Object*>(lw.ForwardingAddress());
+ CHECK(fwd_ptr != nullptr);
+ return fwd_ptr;
+ } else {
+ return nullptr;
+ }
+}
+
+inline void ConcurrentCopying::SetFwdPtr(mirror::Object* from_ref, mirror::Object* to_ref) {
+ DCHECK(region_space_->IsInFromSpace(from_ref));
+ DCHECK(region_space_->IsInToSpace(to_ref) || heap_->GetNonMovingSpace()->HasAddress(to_ref));
+ LockWord lw = from_ref->GetLockWord(false);
+ DCHECK_NE(lw.GetState(), LockWord::kForwardingAddress);
+ from_ref->SetLockWord(LockWord::FromForwardingAddress(reinterpret_cast<size_t>(to_ref)), false);
+}
+
+// The following visitors are that used to verify that there's no
+// references to the from-space left after marking.
+class ConcurrentCopyingVerifyNoFromSpaceRefsVisitor {
+ public:
+ explicit ConcurrentCopyingVerifyNoFromSpaceRefsVisitor(ConcurrentCopying* collector)
+ : collector_(collector) {}
+
+ void operator()(mirror::Object* ref) const
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) ALWAYS_INLINE {
+ if (ref == nullptr) {
+ // OK.
+ return;
+ }
+ collector_->AssertToSpaceInvariant(nullptr, MemberOffset(0), ref);
+ if (kUseBakerReadBarrier) {
+ if (collector_->RegionSpace()->IsInToSpace(ref)) {
+ CHECK(ref->GetReadBarrierPointer() == nullptr)
+ << "To-space ref " << ref << " " << PrettyTypeOf(ref)
+ << " has non-white rb_ptr " << ref->GetReadBarrierPointer();
+ } else {
+ CHECK(ref->GetReadBarrierPointer() == ReadBarrier::BlackPtr() ||
+ (ref->GetReadBarrierPointer() == ReadBarrier::WhitePtr() &&
+ collector_->IsOnAllocStack(ref)))
+ << "Non-moving/unevac from space ref " << ref << " " << PrettyTypeOf(ref)
+ << " has non-black rb_ptr " << ref->GetReadBarrierPointer()
+ << " but isn't on the alloc stack (and has white rb_ptr)."
+ << " Is it in the non-moving space="
+ << (collector_->GetHeap()->GetNonMovingSpace()->HasAddress(ref));
+ }
+ }
+ }
+
+ static void RootCallback(mirror::Object** root, void *arg, const RootInfo& /*root_info*/)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ ConcurrentCopying* collector = reinterpret_cast<ConcurrentCopying*>(arg);
+ ConcurrentCopyingVerifyNoFromSpaceRefsVisitor visitor(collector);
+ DCHECK(root != nullptr);
+ visitor(*root);
+ }
+
+ private:
+ ConcurrentCopying* collector_;
+};
+
+class ConcurrentCopyingVerifyNoFromSpaceRefsFieldVisitor {
+ public:
+ explicit ConcurrentCopyingVerifyNoFromSpaceRefsFieldVisitor(ConcurrentCopying* collector)
+ : collector_(collector) {}
+
+ void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) ALWAYS_INLINE {
+ mirror::Object* ref =
+ obj->GetFieldObject<mirror::Object, kDefaultVerifyFlags, kWithoutReadBarrier>(offset);
+ ConcurrentCopyingVerifyNoFromSpaceRefsVisitor visitor(collector_);
+ visitor(ref);
+ }
+ void operator()(mirror::Class* klass, mirror::Reference* ref) const
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) ALWAYS_INLINE {
+ CHECK(klass->IsTypeOfReferenceClass());
+ this->operator()(ref, mirror::Reference::ReferentOffset(), false);
+ }
+
+ private:
+ ConcurrentCopying* collector_;
+};
+
+class ConcurrentCopyingVerifyNoFromSpaceRefsObjectVisitor {
+ public:
+ explicit ConcurrentCopyingVerifyNoFromSpaceRefsObjectVisitor(ConcurrentCopying* collector)
+ : collector_(collector) {}
+ void operator()(mirror::Object* obj) const
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ ObjectCallback(obj, collector_);
+ }
+ static void ObjectCallback(mirror::Object* obj, void *arg)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ CHECK(obj != nullptr);
+ ConcurrentCopying* collector = reinterpret_cast<ConcurrentCopying*>(arg);
+ space::RegionSpace* region_space = collector->RegionSpace();
+ CHECK(!region_space->IsInFromSpace(obj)) << "Scanning object " << obj << " in from space";
+ ConcurrentCopyingVerifyNoFromSpaceRefsFieldVisitor visitor(collector);
+ obj->VisitReferences<true>(visitor, visitor);
+ if (kUseBakerReadBarrier) {
+ if (collector->RegionSpace()->IsInToSpace(obj)) {
+ CHECK(obj->GetReadBarrierPointer() == nullptr)
+ << "obj=" << obj << " non-white rb_ptr " << obj->GetReadBarrierPointer();
+ } else {
+ CHECK(obj->GetReadBarrierPointer() == ReadBarrier::BlackPtr() ||
+ (obj->GetReadBarrierPointer() == ReadBarrier::WhitePtr() &&
+ collector->IsOnAllocStack(obj)))
+ << "Non-moving space/unevac from space ref " << obj << " " << PrettyTypeOf(obj)
+ << " has non-black rb_ptr " << obj->GetReadBarrierPointer()
+ << " but isn't on the alloc stack (and has white rb_ptr). Is it in the non-moving space="
+ << (collector->GetHeap()->GetNonMovingSpace()->HasAddress(obj));
+ }
+ }
+ }
+
+ private:
+ ConcurrentCopying* const collector_;
+};
+
+// Verify there's no from-space references left after the marking phase.
+void ConcurrentCopying::VerifyNoFromSpaceReferences() {
+ Thread* self = Thread::Current();
+ DCHECK(Locks::mutator_lock_->IsExclusiveHeld(self));
+ ConcurrentCopyingVerifyNoFromSpaceRefsObjectVisitor visitor(this);
+ // Roots.
+ {
+ ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_);
+ Runtime::Current()->VisitRoots(
+ ConcurrentCopyingVerifyNoFromSpaceRefsVisitor::RootCallback, this);
+ }
+ // The to-space.
+ region_space_->WalkToSpace(ConcurrentCopyingVerifyNoFromSpaceRefsObjectVisitor::ObjectCallback,
+ this);
+ // Non-moving spaces.
+ {
+ WriterMutexLock mu(self, *Locks::heap_bitmap_lock_);
+ heap_->GetMarkBitmap()->Visit(visitor);
+ }
+ // The alloc stack.
+ {
+ ConcurrentCopyingVerifyNoFromSpaceRefsVisitor ref_visitor(this);
+ for (mirror::Object** it = heap_->allocation_stack_->Begin(),
+ **end = heap_->allocation_stack_->End(); it < end; ++it) {
+ mirror::Object* obj = *it;
+ if (obj != nullptr && obj->GetClass() != nullptr) {
+ // TODO: need to call this only if obj is alive?
+ ref_visitor(obj);
+ visitor(obj);
+ }
+ }
+ }
+ // TODO: LOS. But only refs in LOS are classes.
+}
+
+// The following visitors are used to assert the to-space invariant.
+class ConcurrentCopyingAssertToSpaceInvariantRefsVisitor {
+ public:
+ explicit ConcurrentCopyingAssertToSpaceInvariantRefsVisitor(ConcurrentCopying* collector)
+ : collector_(collector) {}
+
+ void operator()(mirror::Object* ref) const
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) ALWAYS_INLINE {
+ if (ref == nullptr) {
+ // OK.
+ return;
+ }
+ collector_->AssertToSpaceInvariant(nullptr, MemberOffset(0), ref);
+ }
+ static void RootCallback(mirror::Object** root, void *arg, const RootInfo& /*root_info*/)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ ConcurrentCopying* collector = reinterpret_cast<ConcurrentCopying*>(arg);
+ ConcurrentCopyingAssertToSpaceInvariantRefsVisitor visitor(collector);
+ DCHECK(root != nullptr);
+ visitor(*root);
+ }
+
+ private:
+ ConcurrentCopying* collector_;
+};
+
+class ConcurrentCopyingAssertToSpaceInvariantFieldVisitor {
+ public:
+ explicit ConcurrentCopyingAssertToSpaceInvariantFieldVisitor(ConcurrentCopying* collector)
+ : collector_(collector) {}
+
+ void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) ALWAYS_INLINE {
+ mirror::Object* ref =
+ obj->GetFieldObject<mirror::Object, kDefaultVerifyFlags, kWithoutReadBarrier>(offset);
+ ConcurrentCopyingAssertToSpaceInvariantRefsVisitor visitor(collector_);
+ visitor(ref);
+ }
+ void operator()(mirror::Class* klass, mirror::Reference* /* ref */) const
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) ALWAYS_INLINE {
+ CHECK(klass->IsTypeOfReferenceClass());
+ }
+
+ private:
+ ConcurrentCopying* collector_;
+};
+
+class ConcurrentCopyingAssertToSpaceInvariantObjectVisitor {
+ public:
+ explicit ConcurrentCopyingAssertToSpaceInvariantObjectVisitor(ConcurrentCopying* collector)
+ : collector_(collector) {}
+ void operator()(mirror::Object* obj) const
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ ObjectCallback(obj, collector_);
+ }
+ static void ObjectCallback(mirror::Object* obj, void *arg)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ CHECK(obj != nullptr);
+ ConcurrentCopying* collector = reinterpret_cast<ConcurrentCopying*>(arg);
+ space::RegionSpace* region_space = collector->RegionSpace();
+ CHECK(!region_space->IsInFromSpace(obj)) << "Scanning object " << obj << " in from space";
+ collector->AssertToSpaceInvariant(nullptr, MemberOffset(0), obj);
+ ConcurrentCopyingAssertToSpaceInvariantFieldVisitor visitor(collector);
+ obj->VisitReferences<true>(visitor, visitor);
+ }
+
+ private:
+ ConcurrentCopying* collector_;
+};
+
+bool ConcurrentCopying::ProcessMarkStack() {
+ if (kVerboseMode) {
+ LOG(INFO) << "ProcessMarkStack. ";
+ }
+ size_t count = 0;
+ mirror::Object* to_ref;
+ while ((to_ref = PopOffMarkStack()) != nullptr) {
+ ++count;
+ DCHECK(!region_space_->IsInFromSpace(to_ref));
+ if (kUseBakerReadBarrier) {
+ DCHECK(to_ref->GetReadBarrierPointer() == ReadBarrier::GrayPtr())
+ << " " << to_ref << " " << to_ref->GetReadBarrierPointer()
+ << " is_marked=" << IsMarked(to_ref);
+ }
+ // Scan ref fields.
+ Scan(to_ref);
+ // Mark the gray ref as white or black.
+ if (kUseBakerReadBarrier) {
+ DCHECK(to_ref->GetReadBarrierPointer() == ReadBarrier::GrayPtr())
+ << " " << to_ref << " " << to_ref->GetReadBarrierPointer()
+ << " is_marked=" << IsMarked(to_ref);
+ }
+ if (to_ref->GetClass<kVerifyNone, kWithoutReadBarrier>()->IsTypeOfReferenceClass() &&
+ to_ref->AsReference()->GetReferent<kWithoutReadBarrier>() != nullptr &&
+ !IsInToSpace(to_ref->AsReference()->GetReferent<kWithoutReadBarrier>())) {
+ // Leave References gray so that GetReferent() will trigger RB.
+ CHECK(to_ref->AsReference()->IsEnqueued()) << "Left unenqueued ref gray " << to_ref;
+ } else {
+ if (kUseBakerReadBarrier) {
+ if (region_space_->IsInToSpace(to_ref)) {
+ // If to-space, change from gray to white.
+ bool success = to_ref->AtomicSetReadBarrierPointer(ReadBarrier::GrayPtr(),
+ ReadBarrier::WhitePtr());
+ CHECK(success) << "Must succeed as we won the race.";
+ CHECK(to_ref->GetReadBarrierPointer() == ReadBarrier::WhitePtr());
+ } else {
+ // If non-moving space/unevac from space, change from gray
+ // to black. We can't change gray to white because it's not
+ // safe to use CAS if two threads change values in opposite
+ // directions (A->B and B->A). So, we change it to black to
+ // indicate non-moving objects that have been marked
+ // through. Note we'd need to change from black to white
+ // later (concurrently).
+ bool success = to_ref->AtomicSetReadBarrierPointer(ReadBarrier::GrayPtr(),
+ ReadBarrier::BlackPtr());
+ CHECK(success) << "Must succeed as we won the race.";
+ CHECK(to_ref->GetReadBarrierPointer() == ReadBarrier::BlackPtr());
+ }
+ }
+ }
+ if (ReadBarrier::kEnableToSpaceInvariantChecks || kIsDebugBuild) {
+ ConcurrentCopyingAssertToSpaceInvariantObjectVisitor visitor(this);
+ visitor(to_ref);
+ }
+ }
+ // Return true if the stack was empty.
+ return count == 0;
+}
+
+void ConcurrentCopying::CheckEmptyMarkQueue() {
+ if (!mark_queue_.IsEmpty()) {
+ while (!mark_queue_.IsEmpty()) {
+ mirror::Object* obj = mark_queue_.Dequeue();
+ if (kUseBakerReadBarrier) {
+ mirror::Object* rb_ptr = obj->GetReadBarrierPointer();
+ LOG(INFO) << "On mark queue : " << obj << " " << PrettyTypeOf(obj) << " rb_ptr=" << rb_ptr
+ << " is_marked=" << IsMarked(obj);
+ } else {
+ LOG(INFO) << "On mark queue : " << obj << " " << PrettyTypeOf(obj)
+ << " is_marked=" << IsMarked(obj);
+ }
+ }
+ LOG(FATAL) << "mark queue is not empty";
+ }
+}
+
+void ConcurrentCopying::SweepSystemWeaks(Thread* self) {
+ TimingLogger::ScopedTiming split("SweepSystemWeaks", GetTimings());
+ ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_);
+ Runtime::Current()->SweepSystemWeaks(IsMarkedCallback, this);
+}
+
+void ConcurrentCopying::Sweep(bool swap_bitmaps) {
+ {
+ TimingLogger::ScopedTiming t("MarkStackAsLive", GetTimings());
+ accounting::ObjectStack* live_stack = heap_->GetLiveStack();
+ if (kEnableFromSpaceAccountingCheck) {
+ CHECK_GE(live_stack_freeze_size_, live_stack->Size());
+ }
+ heap_->MarkAllocStackAsLive(live_stack);
+ live_stack->Reset();
+ }
+ CHECK(mark_queue_.IsEmpty());
+ TimingLogger::ScopedTiming split("Sweep", GetTimings());
+ for (const auto& space : GetHeap()->GetContinuousSpaces()) {
+ if (space->IsContinuousMemMapAllocSpace()) {
+ space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace();
+ if (space == region_space_ || immune_region_.ContainsSpace(space)) {
+ continue;
+ }
+ TimingLogger::ScopedTiming split2(
+ alloc_space->IsZygoteSpace() ? "SweepZygoteSpace" : "SweepAllocSpace", GetTimings());
+ RecordFree(alloc_space->Sweep(swap_bitmaps));
+ }
+ }
+ SweepLargeObjects(swap_bitmaps);
+}
+
+void ConcurrentCopying::SweepLargeObjects(bool swap_bitmaps) {
+ TimingLogger::ScopedTiming split("SweepLargeObjects", GetTimings());
+ RecordFreeLOS(heap_->GetLargeObjectsSpace()->Sweep(swap_bitmaps));
+}
+
+class ConcurrentCopyingClearBlackPtrsVisitor {
+ public:
+ explicit ConcurrentCopyingClearBlackPtrsVisitor(ConcurrentCopying* cc)
+ : collector_(cc) {}
+ void operator()(mirror::Object* obj) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
+ SHARED_LOCKS_REQUIRED(Locks::heap_bitmap_lock_) {
+ DCHECK(obj != nullptr);
+ CHECK(collector_->heap_->GetMarkBitmap()->Test(obj)) << obj;
+ CHECK_EQ(obj->GetReadBarrierPointer(), ReadBarrier::BlackPtr()) << obj;
+ obj->SetReadBarrierPointer(ReadBarrier::WhitePtr());
+ CHECK_EQ(obj->GetReadBarrierPointer(), ReadBarrier::WhitePtr()) << obj;
+ }
+
+ private:
+ ConcurrentCopying* const collector_;
+};
+
+// Clear the black ptrs in non-moving objects back to white.
+void ConcurrentCopying::ClearBlackPtrs() {
+ CHECK(kUseBakerReadBarrier);
+ TimingLogger::ScopedTiming split("ClearBlackPtrs", GetTimings());
+ ConcurrentCopyingClearBlackPtrsVisitor visitor(this);
+ for (auto& space : heap_->GetContinuousSpaces()) {
+ if (space == region_space_) {
+ continue;
+ }
+ accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap();
+ if (kVerboseMode) {
+ LOG(INFO) << "ClearBlackPtrs: " << *space << " bitmap: " << *mark_bitmap;
+ }
+ mark_bitmap->VisitMarkedRange(reinterpret_cast<uintptr_t>(space->Begin()),
+ reinterpret_cast<uintptr_t>(space->Limit()),
+ visitor);
+ }
+ space::LargeObjectSpace* large_object_space = heap_->GetLargeObjectsSpace();
+ large_object_space->GetMarkBitmap()->VisitMarkedRange(
+ reinterpret_cast<uintptr_t>(large_object_space->Begin()),
+ reinterpret_cast<uintptr_t>(large_object_space->End()),
+ visitor);
+ // Objects on the allocation stack?
+ if (ReadBarrier::kEnableReadBarrierInvariantChecks || kIsDebugBuild) {
+ size_t count = GetAllocationStack()->Size();
+ mirror::Object** it = GetAllocationStack()->Begin();
+ mirror::Object** end = GetAllocationStack()->End();
+ for (size_t i = 0; i < count; ++i, ++it) {
+ CHECK(it < end);
+ mirror::Object* obj = *it;
+ if (obj != nullptr) {
+ // Must have been cleared above.
+ CHECK(obj->GetReadBarrierPointer() == ReadBarrier::WhitePtr()) << obj;
+ }
+ }
+ }
+}
+
+void ConcurrentCopying::ReclaimPhase() {
+ TimingLogger::ScopedTiming split("ReclaimPhase", GetTimings());
+ if (kVerboseMode) {
+ LOG(INFO) << "GC ReclaimPhase";
+ }
+ Thread* self = Thread::Current();
+
+ {
+ // Double-check that the mark stack is empty.
+ // Note: need to set this after VerifyNoFromSpaceRef().
+ is_asserting_to_space_invariant_ = false;
+ QuasiAtomic::ThreadFenceForConstructor();
+ if (kVerboseMode) {
+ LOG(INFO) << "Issue an empty check point. ";
+ }
+ IssueEmptyCheckpoint();
+ // Disable the check.
+ is_mark_queue_push_disallowed_.StoreSequentiallyConsistent(0);
+ CheckEmptyMarkQueue();
+ }
+
+ {
+ // Record freed objects.
+ TimingLogger::ScopedTiming split2("RecordFree", GetTimings());
+ // Don't include thread-locals that are in the to-space.
+ uint64_t from_bytes = region_space_->GetBytesAllocatedInFromSpace();
+ uint64_t from_objects = region_space_->GetObjectsAllocatedInFromSpace();
+ uint64_t unevac_from_bytes = region_space_->GetBytesAllocatedInUnevacFromSpace();
+ uint64_t unevac_from_objects = region_space_->GetObjectsAllocatedInUnevacFromSpace();
+ uint64_t to_bytes = bytes_moved_.LoadSequentiallyConsistent();
+ uint64_t to_objects = objects_moved_.LoadSequentiallyConsistent();
+ if (kEnableFromSpaceAccountingCheck) {
+ CHECK_EQ(from_space_num_objects_at_first_pause_, from_objects + unevac_from_objects);
+ CHECK_EQ(from_space_num_bytes_at_first_pause_, from_bytes + unevac_from_bytes);
+ }
+ CHECK_LE(to_objects, from_objects);
+ CHECK_LE(to_bytes, from_bytes);
+ int64_t freed_bytes = from_bytes - to_bytes;
+ int64_t freed_objects = from_objects - to_objects;
+ if (kVerboseMode) {
+ LOG(INFO) << "RecordFree:"
+ << " from_bytes=" << from_bytes << " from_objects=" << from_objects
+ << " unevac_from_bytes=" << unevac_from_bytes << " unevac_from_objects=" << unevac_from_objects
+ << " to_bytes=" << to_bytes << " to_objects=" << to_objects
+ << " freed_bytes=" << freed_bytes << " freed_objects=" << freed_objects
+ << " from_space size=" << region_space_->FromSpaceSize()
+ << " unevac_from_space size=" << region_space_->UnevacFromSpaceSize()
+ << " to_space size=" << region_space_->ToSpaceSize();
+ LOG(INFO) << "(before) num_bytes_allocated=" << heap_->num_bytes_allocated_.LoadSequentiallyConsistent();
+ }
+ RecordFree(ObjectBytePair(freed_objects, freed_bytes));
+ if (kVerboseMode) {
+ LOG(INFO) << "(after) num_bytes_allocated=" << heap_->num_bytes_allocated_.LoadSequentiallyConsistent();
+ }
+ }
+
+ {
+ TimingLogger::ScopedTiming split3("ComputeUnevacFromSpaceLiveRatio", GetTimings());
+ ComputeUnevacFromSpaceLiveRatio();
+ }
+
+ {
+ TimingLogger::ScopedTiming split4("ClearFromSpace", GetTimings());
+ region_space_->ClearFromSpace();
+ }
+
+ {
+ WriterMutexLock mu(self, *Locks::heap_bitmap_lock_);
+ if (kUseBakerReadBarrier) {
+ ClearBlackPtrs();
+ }
+ Sweep(false);
+ SwapBitmaps();
+ heap_->UnBindBitmaps();
+
+ // Remove bitmaps for the immune spaces.
+ while (!cc_bitmaps_.empty()) {
+ accounting::ContinuousSpaceBitmap* cc_bitmap = cc_bitmaps_.back();
+ cc_heap_bitmap_->RemoveContinuousSpaceBitmap(cc_bitmap);
+ delete cc_bitmap;
+ cc_bitmaps_.pop_back();
+ }
+ region_space_bitmap_ = nullptr;
+ }
+
+ if (kVerboseMode) {
+ LOG(INFO) << "GC end of ReclaimPhase";
+ }
+}
+
+class ConcurrentCopyingComputeUnevacFromSpaceLiveRatioVisitor {
+ public:
+ explicit ConcurrentCopyingComputeUnevacFromSpaceLiveRatioVisitor(ConcurrentCopying* cc)
+ : collector_(cc) {}
+ void operator()(mirror::Object* ref) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
+ SHARED_LOCKS_REQUIRED(Locks::heap_bitmap_lock_) {
+ DCHECK(ref != nullptr);
+ CHECK(collector_->region_space_bitmap_->Test(ref)) << ref;
+ CHECK(collector_->region_space_->IsInUnevacFromSpace(ref)) << ref;
+ if (kUseBakerReadBarrier) {
+ CHECK(ref->GetReadBarrierPointer() == ReadBarrier::BlackPtr()) << ref;
+ // Clear the black ptr.
+ ref->SetReadBarrierPointer(ReadBarrier::WhitePtr());
+ }
+ size_t obj_size = ref->SizeOf();
+ size_t alloc_size = RoundUp(obj_size, space::RegionSpace::kAlignment);
+ collector_->region_space_->AddLiveBytes(ref, alloc_size);
+ }
+
+ private:
+ ConcurrentCopying* collector_;
+};
+
+// Compute how much live objects are left in regions.
+void ConcurrentCopying::ComputeUnevacFromSpaceLiveRatio() {
+ region_space_->AssertAllRegionLiveBytesZeroOrCleared();
+ ConcurrentCopyingComputeUnevacFromSpaceLiveRatioVisitor visitor(this);
+ region_space_bitmap_->VisitMarkedRange(reinterpret_cast<uintptr_t>(region_space_->Begin()),
+ reinterpret_cast<uintptr_t>(region_space_->Limit()),
+ visitor);
+}
+
+// Assert the to-space invariant.
+void ConcurrentCopying::AssertToSpaceInvariant(mirror::Object* obj, MemberOffset offset,
+ mirror::Object* ref) {
+ CHECK(heap_->collector_type_ == kCollectorTypeCC) << static_cast<size_t>(heap_->collector_type_);
+ if (is_asserting_to_space_invariant_) {
+ if (region_space_->IsInToSpace(ref)) {
+ // OK.
+ return;
+ } else if (region_space_->IsInUnevacFromSpace(ref)) {
+ CHECK(region_space_bitmap_->Test(ref)) << ref;
+ } else if (region_space_->IsInFromSpace(ref)) {
+ // Not OK. Do extra logging.
+ if (obj != nullptr) {
+ if (kUseBakerReadBarrier) {
+ LOG(INFO) << "holder=" << obj << " " << PrettyTypeOf(obj)
+ << " holder rb_ptr=" << obj->GetReadBarrierPointer();
+ } else {
+ LOG(INFO) << "holder=" << obj << " " << PrettyTypeOf(obj);
+ }
+ if (region_space_->IsInFromSpace(obj)) {
+ LOG(INFO) << "holder is in the from-space.";
+ } else if (region_space_->IsInToSpace(obj)) {
+ LOG(INFO) << "holder is in the to-space.";
+ } else if (region_space_->IsInUnevacFromSpace(obj)) {
+ LOG(INFO) << "holder is in the unevac from-space.";
+ if (region_space_bitmap_->Test(obj)) {
+ LOG(INFO) << "holder is marked in the region space bitmap.";
+ } else {
+ LOG(INFO) << "holder is not marked in the region space bitmap.";
+ }
+ } else {
+ // In a non-moving space.
+ if (immune_region_.ContainsObject(obj)) {
+ LOG(INFO) << "holder is in the image or the zygote space.";
+ accounting::ContinuousSpaceBitmap* cc_bitmap =
+ cc_heap_bitmap_->GetContinuousSpaceBitmap(obj);
+ CHECK(cc_bitmap != nullptr)
+ << "An immune space object must have a bitmap.";
+ if (cc_bitmap->Test(obj)) {
+ LOG(INFO) << "holder is marked in the bit map.";
+ } else {
+ LOG(INFO) << "holder is NOT marked in the bit map.";
+ }
+ } else {
+ LOG(INFO) << "holder is in a non-moving (or main) space.";
+ accounting::ContinuousSpaceBitmap* mark_bitmap =
+ heap_mark_bitmap_->GetContinuousSpaceBitmap(obj);
+ accounting::LargeObjectBitmap* los_bitmap =
+ heap_mark_bitmap_->GetLargeObjectBitmap(obj);
+ CHECK(los_bitmap != nullptr) << "LOS bitmap covers the entire address range";
+ bool is_los = mark_bitmap == nullptr;
+ if (!is_los && mark_bitmap->Test(obj)) {
+ LOG(INFO) << "holder is marked in the mark bit map.";
+ } else if (is_los && los_bitmap->Test(obj)) {
+ LOG(INFO) << "holder is marked in the los bit map.";
+ } else {
+ // If ref is on the allocation stack, then it is considered
+ // mark/alive (but not necessarily on the live stack.)
+ if (IsOnAllocStack(obj)) {
+ LOG(INFO) << "holder is on the alloc stack.";
+ } else {
+ LOG(INFO) << "holder is not marked or on the alloc stack.";
+ }
+ }
+ }
+ }
+ LOG(INFO) << "offset=" << offset.SizeValue();
+ }
+ CHECK(false) << "Found from-space ref " << ref << " " << PrettyTypeOf(ref);
+ } else {
+ // In a non-moving spaces. Check that the ref is marked.
+ if (immune_region_.ContainsObject(ref)) {
+ accounting::ContinuousSpaceBitmap* cc_bitmap =
+ cc_heap_bitmap_->GetContinuousSpaceBitmap(ref);
+ CHECK(cc_bitmap != nullptr)
+ << "An immune space ref must have a bitmap. " << ref;
+ if (kUseBakerReadBarrier) {
+ CHECK(cc_bitmap->Test(ref))
+ << "Unmarked immune space ref. obj=" << obj << " rb_ptr="
+ << obj->GetReadBarrierPointer() << " ref=" << ref;
+ } else {
+ CHECK(cc_bitmap->Test(ref))
+ << "Unmarked immune space ref. obj=" << obj << " ref=" << ref;
+ }
+ } else {
+ accounting::ContinuousSpaceBitmap* mark_bitmap =
+ heap_mark_bitmap_->GetContinuousSpaceBitmap(ref);
+ accounting::LargeObjectBitmap* los_bitmap =
+ heap_mark_bitmap_->GetLargeObjectBitmap(ref);
+ CHECK(los_bitmap != nullptr) << "LOS bitmap covers the entire address range";
+ bool is_los = mark_bitmap == nullptr;
+ if ((!is_los && mark_bitmap->Test(ref)) ||
+ (is_los && los_bitmap->Test(ref))) {
+ // OK.
+ } else {
+ // If ref is on the allocation stack, then it may not be
+ // marked live, but considered marked/alive (but not
+ // necessarily on the live stack).
+ CHECK(IsOnAllocStack(ref)) << "Unmarked ref that's not on the allocation stack. "
+ << "obj=" << obj << " ref=" << ref;
+ }
+ }
+ }
+ }
+}
+
+void ConcurrentCopying::ProcessRootCallback(mirror::Object** root, void* arg,
+ const RootInfo& /*root_info*/) {
+ reinterpret_cast<ConcurrentCopying*>(arg)->Process(root);
+}
+
+// Used to scan ref fields of an object.
+class ConcurrentCopyingRefFieldsVisitor {
+ public:
+ explicit ConcurrentCopyingRefFieldsVisitor(ConcurrentCopying* collector)
+ : collector_(collector) {}
+
+ void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */)
+ const ALWAYS_INLINE SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
+ SHARED_LOCKS_REQUIRED(Locks::heap_bitmap_lock_) {
+ collector_->Process(obj, offset);
+ }
+
+ void operator()(mirror::Class* klass, mirror::Reference* ref) const
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) ALWAYS_INLINE {
+ CHECK(klass->IsTypeOfReferenceClass());
+ collector_->DelayReferenceReferent(klass, ref);
+ }
+
+ private:
+ ConcurrentCopying* const collector_;
+};
+
+// Scan ref fields of an object.
+void ConcurrentCopying::Scan(mirror::Object* to_ref) {
+ DCHECK(!region_space_->IsInFromSpace(to_ref));
+ ConcurrentCopyingRefFieldsVisitor visitor(this);
+ to_ref->VisitReferences<true>(visitor, visitor);
+}
+
+// Process a field.
+inline void ConcurrentCopying::Process(mirror::Object* obj, MemberOffset offset) {
+ mirror::Object* ref = obj->GetFieldObject<mirror::Object, kVerifyNone, kWithoutReadBarrier, false>(offset);
+ if (ref == nullptr || region_space_->IsInToSpace(ref)) {
+ return;
+ }
+ mirror::Object* to_ref = Mark(ref);
+ if (to_ref == ref) {
+ return;
+ }
+ // This may fail if the mutator writes to the field at the same time. But it's ok.
+ mirror::Object* expected_ref = ref;
+ mirror::Object* new_ref = to_ref;
+ do {
+ if (expected_ref !=
+ obj->GetFieldObject<mirror::Object, kVerifyNone, kWithoutReadBarrier, false>(offset)) {
+ // It was updated by the mutator.
+ break;
+ }
+ } while (!obj->CasFieldWeakSequentiallyConsistentObjectWithoutWriteBarrier<false, false, kVerifyNone>(
+ offset, expected_ref, new_ref));
+}
+
+// Process a root.
+void ConcurrentCopying::Process(mirror::Object** root) {
+ mirror::Object* ref = *root;
+ if (ref == nullptr || region_space_->IsInToSpace(ref)) {
+ return;
+ }
+ mirror::Object* to_ref = Mark(ref);
+ if (to_ref == ref) {
+ return;
+ }
+ Atomic<mirror::Object*>* addr = reinterpret_cast<Atomic<mirror::Object*>*>(root);
+ mirror::Object* expected_ref = ref;
+ mirror::Object* new_ref = to_ref;
+ do {
+ if (expected_ref != addr->LoadRelaxed()) {
+ // It was updated by the mutator.
+ break;
+ }
+ } while (!addr->CompareExchangeWeakSequentiallyConsistent(expected_ref, new_ref));
+}
+
+// Fill the given memory block with a dummy object. Used to fill in a
+// copy of objects that was lost in race.
+void ConcurrentCopying::FillWithDummyObject(mirror::Object* dummy_obj, size_t byte_size) {
+ CHECK(IsAligned<kObjectAlignment>(byte_size));
+ memset(dummy_obj, 0, byte_size);
+ mirror::Class* int_array_class = mirror::IntArray::GetArrayClass();
+ CHECK(int_array_class != nullptr);
+ AssertToSpaceInvariant(nullptr, MemberOffset(0), int_array_class);
+ size_t component_size = int_array_class->GetComponentSize();
+ CHECK_EQ(component_size, sizeof(int32_t));
+ size_t data_offset = mirror::Array::DataOffset(component_size).SizeValue();
+ if (data_offset > byte_size) {
+ // An int array is too big. Use java.lang.Object.
+ mirror::Class* java_lang_Object = WellKnownClasses::ToClass(WellKnownClasses::java_lang_Object);
+ AssertToSpaceInvariant(nullptr, MemberOffset(0), java_lang_Object);
+ CHECK_EQ(byte_size, java_lang_Object->GetObjectSize());
+ dummy_obj->SetClass(java_lang_Object);
+ CHECK_EQ(byte_size, dummy_obj->SizeOf());
+ } else {
+ // Use an int array.
+ dummy_obj->SetClass(int_array_class);
+ CHECK(dummy_obj->IsArrayInstance());
+ int32_t length = (byte_size - data_offset) / component_size;
+ dummy_obj->AsArray()->SetLength(length);
+ CHECK_EQ(dummy_obj->AsArray()->GetLength(), length)
+ << "byte_size=" << byte_size << " length=" << length
+ << " component_size=" << component_size << " data_offset=" << data_offset;
+ CHECK_EQ(byte_size, dummy_obj->SizeOf())
+ << "byte_size=" << byte_size << " length=" << length
+ << " component_size=" << component_size << " data_offset=" << data_offset;
+ }
+}
+
+// Reuse the memory blocks that were copy of objects that were lost in race.
+mirror::Object* ConcurrentCopying::AllocateInSkippedBlock(size_t alloc_size) {
+ // Try to reuse the blocks that were unused due to CAS failures.
+ CHECK(IsAligned<space::RegionSpace::kAlignment>(alloc_size));
+ Thread* self = Thread::Current();
+ size_t min_object_size = RoundUp(sizeof(mirror::Object), space::RegionSpace::kAlignment);
+ MutexLock mu(self, skipped_blocks_lock_);
+ auto it = skipped_blocks_map_.lower_bound(alloc_size);
+ if (it == skipped_blocks_map_.end()) {
+ // Not found.
+ return nullptr;
+ }
+ {
+ size_t byte_size = it->first;
+ CHECK_GE(byte_size, alloc_size);
+ if (byte_size > alloc_size && byte_size - alloc_size < min_object_size) {
+ // If remainder would be too small for a dummy object, retry with a larger request size.
+ it = skipped_blocks_map_.lower_bound(alloc_size + min_object_size);
+ if (it == skipped_blocks_map_.end()) {
+ // Not found.
+ return nullptr;
+ }
+ CHECK(IsAligned<space::RegionSpace::kAlignment>(it->first - alloc_size));
+ CHECK_GE(it->first - alloc_size, min_object_size)
+ << "byte_size=" << byte_size << " it->first=" << it->first << " alloc_size=" << alloc_size;
+ }
+ }
+ // Found a block.
+ CHECK(it != skipped_blocks_map_.end());
+ size_t byte_size = it->first;
+ uint8_t* addr = it->second;
+ CHECK_GE(byte_size, alloc_size);
+ CHECK(region_space_->IsInToSpace(reinterpret_cast<mirror::Object*>(addr)));
+ CHECK(IsAligned<space::RegionSpace::kAlignment>(byte_size));
+ if (kVerboseMode) {
+ LOG(INFO) << "Reusing skipped bytes : " << reinterpret_cast<void*>(addr) << ", " << byte_size;
+ }
+ skipped_blocks_map_.erase(it);
+ memset(addr, 0, byte_size);
+ if (byte_size > alloc_size) {
+ // Return the remainder to the map.
+ CHECK(IsAligned<space::RegionSpace::kAlignment>(byte_size - alloc_size));
+ CHECK_GE(byte_size - alloc_size, min_object_size);
+ FillWithDummyObject(reinterpret_cast<mirror::Object*>(addr + alloc_size),
+ byte_size - alloc_size);
+ CHECK(region_space_->IsInToSpace(reinterpret_cast<mirror::Object*>(addr + alloc_size)));
+ skipped_blocks_map_.insert(std::make_pair(byte_size - alloc_size, addr + alloc_size));
+ }
+ return reinterpret_cast<mirror::Object*>(addr);
+}
+
+mirror::Object* ConcurrentCopying::Copy(mirror::Object* from_ref) {
+ DCHECK(region_space_->IsInFromSpace(from_ref));
+ // No read barrier to avoid nested RB that might violate the to-space
+ // invariant. Note that from_ref is a from space ref so the SizeOf()
+ // call will access the from-space meta objects, but it's ok and necessary.
+ size_t obj_size = from_ref->SizeOf<kDefaultVerifyFlags, kWithoutReadBarrier>();
+ size_t region_space_alloc_size = RoundUp(obj_size, space::RegionSpace::kAlignment);
+ size_t region_space_bytes_allocated = 0U;
+ size_t non_moving_space_bytes_allocated = 0U;
+ size_t bytes_allocated = 0U;
+ mirror::Object* to_ref = region_space_->AllocNonvirtual<true>(
+ region_space_alloc_size, ®ion_space_bytes_allocated, nullptr);
+ bytes_allocated = region_space_bytes_allocated;
+ if (to_ref != nullptr) {
+ DCHECK_EQ(region_space_alloc_size, region_space_bytes_allocated);
+ }
+ bool fall_back_to_non_moving = false;
+ if (UNLIKELY(to_ref == nullptr)) {
+ // Failed to allocate in the region space. Try the skipped blocks.
+ to_ref = AllocateInSkippedBlock(region_space_alloc_size);
+ if (to_ref != nullptr) {
+ // Succeeded to allocate in a skipped block.
+ if (heap_->use_tlab_) {
+ // This is necessary for the tlab case as it's not accounted in the space.
+ region_space_->RecordAlloc(to_ref);
+ }
+ bytes_allocated = region_space_alloc_size;
+ } else {
+ // Fall back to the non-moving space.
+ fall_back_to_non_moving = true;
+ if (kVerboseMode) {
+ LOG(INFO) << "Out of memory in the to-space. Fall back to non-moving. skipped_bytes="
+ << to_space_bytes_skipped_.LoadSequentiallyConsistent()
+ << " skipped_objects=" << to_space_objects_skipped_.LoadSequentiallyConsistent();
+ }
+ fall_back_to_non_moving = true;
+ to_ref = heap_->non_moving_space_->Alloc(Thread::Current(), obj_size,
+ &non_moving_space_bytes_allocated, nullptr);
+ CHECK(to_ref != nullptr) << "Fall-back non-moving space allocation failed";
+ bytes_allocated = non_moving_space_bytes_allocated;
+ // Mark it in the mark bitmap.
+ accounting::ContinuousSpaceBitmap* mark_bitmap =
+ heap_mark_bitmap_->GetContinuousSpaceBitmap(to_ref);
+ CHECK(mark_bitmap != nullptr);
+ CHECK(!mark_bitmap->AtomicTestAndSet(to_ref));
+ }
+ }
+ DCHECK(to_ref != nullptr);
+
+ // Attempt to install the forward pointer. This is in a loop as the
+ // lock word atomic write can fail.
+ while (true) {
+ // Copy the object. TODO: copy only the lockword in the second iteration and on?
+ memcpy(to_ref, from_ref, obj_size);
+ // Set the gray ptr.
+ if (kUseBakerReadBarrier) {
+ to_ref->SetReadBarrierPointer(ReadBarrier::GrayPtr());
+ }
+
+ LockWord old_lock_word = to_ref->GetLockWord(false);
+
+ if (old_lock_word.GetState() == LockWord::kForwardingAddress) {
+ // Lost the race. Another thread (either GC or mutator) stored
+ // the forwarding pointer first. Make the lost copy (to_ref)
+ // look like a valid but dead (dummy) object and keep it for
+ // future reuse.
+ FillWithDummyObject(to_ref, bytes_allocated);
+ if (!fall_back_to_non_moving) {
+ DCHECK(region_space_->IsInToSpace(to_ref));
+ if (bytes_allocated > space::RegionSpace::kRegionSize) {
+ // Free the large alloc.
+ region_space_->FreeLarge(to_ref, bytes_allocated);
+ } else {
+ // Record the lost copy for later reuse.
+ heap_->num_bytes_allocated_.FetchAndAddSequentiallyConsistent(bytes_allocated);
+ to_space_bytes_skipped_.FetchAndAddSequentiallyConsistent(bytes_allocated);
+ to_space_objects_skipped_.FetchAndAddSequentiallyConsistent(1);
+ MutexLock mu(Thread::Current(), skipped_blocks_lock_);
+ skipped_blocks_map_.insert(std::make_pair(bytes_allocated,
+ reinterpret_cast<uint8_t*>(to_ref)));
+ }
+ } else {
+ DCHECK(heap_->non_moving_space_->HasAddress(to_ref));
+ DCHECK_EQ(bytes_allocated, non_moving_space_bytes_allocated);
+ // Free the non-moving-space chunk.
+ accounting::ContinuousSpaceBitmap* mark_bitmap =
+ heap_mark_bitmap_->GetContinuousSpaceBitmap(to_ref);
+ CHECK(mark_bitmap != nullptr);
+ CHECK(mark_bitmap->Clear(to_ref));
+ heap_->non_moving_space_->Free(Thread::Current(), to_ref);
+ }
+
+ // Get the winner's forward ptr.
+ mirror::Object* lost_fwd_ptr = to_ref;
+ to_ref = reinterpret_cast<mirror::Object*>(old_lock_word.ForwardingAddress());
+ CHECK(to_ref != nullptr);
+ CHECK_NE(to_ref, lost_fwd_ptr);
+ CHECK(region_space_->IsInToSpace(to_ref) || heap_->non_moving_space_->HasAddress(to_ref));
+ CHECK_NE(to_ref->GetLockWord(false).GetState(), LockWord::kForwardingAddress);
+ return to_ref;
+ }
+
+ LockWord new_lock_word = LockWord::FromForwardingAddress(reinterpret_cast<size_t>(to_ref));
+
+ // Try to atomically write the fwd ptr.
+ bool success = from_ref->CasLockWordWeakSequentiallyConsistent(old_lock_word, new_lock_word);
+ if (LIKELY(success)) {
+ // The CAS succeeded.
+ objects_moved_.FetchAndAddSequentiallyConsistent(1);
+ bytes_moved_.FetchAndAddSequentiallyConsistent(region_space_alloc_size);
+ if (LIKELY(!fall_back_to_non_moving)) {
+ DCHECK(region_space_->IsInToSpace(to_ref));
+ } else {
+ DCHECK(heap_->non_moving_space_->HasAddress(to_ref));
+ DCHECK_EQ(bytes_allocated, non_moving_space_bytes_allocated);
+ }
+ if (kUseBakerReadBarrier) {
+ DCHECK(to_ref->GetReadBarrierPointer() == ReadBarrier::GrayPtr());
+ }
+ DCHECK(GetFwdPtr(from_ref) == to_ref);
+ CHECK_NE(to_ref->GetLockWord(false).GetState(), LockWord::kForwardingAddress);
+ PushOntoMarkStack<true>(to_ref);
+ return to_ref;
+ } else {
+ // The CAS failed. It may have lost the race or may have failed
+ // due to monitor/hashcode ops. Either way, retry.
+ }
+ }
+}
+
+mirror::Object* ConcurrentCopying::IsMarked(mirror::Object* from_ref) {
+ DCHECK(from_ref != nullptr);
+ if (region_space_->IsInToSpace(from_ref)) {
+ // It's already marked.
+ return from_ref;
+ }
+ mirror::Object* to_ref;
+ if (region_space_->IsInFromSpace(from_ref)) {
+ to_ref = GetFwdPtr(from_ref);
+ DCHECK(to_ref == nullptr || region_space_->IsInToSpace(to_ref) ||
+ heap_->non_moving_space_->HasAddress(to_ref))
+ << "from_ref=" << from_ref << " to_ref=" << to_ref;
+ } else if (region_space_->IsInUnevacFromSpace(from_ref)) {
+ if (region_space_bitmap_->Test(from_ref)) {
+ to_ref = from_ref;
+ } else {
+ to_ref = nullptr;
+ }
+ } else {
+ // from_ref is in a non-moving space.
+ if (immune_region_.ContainsObject(from_ref)) {
+ accounting::ContinuousSpaceBitmap* cc_bitmap =
+ cc_heap_bitmap_->GetContinuousSpaceBitmap(from_ref);
+ DCHECK(cc_bitmap != nullptr)
+ << "An immune space object must have a bitmap";
+ if (kIsDebugBuild) {
+ DCHECK(heap_mark_bitmap_->GetContinuousSpaceBitmap(from_ref)->Test(from_ref))
+ << "Immune space object must be already marked";
+ }
+ if (cc_bitmap->Test(from_ref)) {
+ // Already marked.
+ to_ref = from_ref;
+ } else {
+ // Newly marked.
+ to_ref = nullptr;
+ }
+ } else {
+ // Non-immune non-moving space. Use the mark bitmap.
+ accounting::ContinuousSpaceBitmap* mark_bitmap =
+ heap_mark_bitmap_->GetContinuousSpaceBitmap(from_ref);
+ accounting::LargeObjectBitmap* los_bitmap =
+ heap_mark_bitmap_->GetLargeObjectBitmap(from_ref);
+ CHECK(los_bitmap != nullptr) << "LOS bitmap covers the entire address range";
+ bool is_los = mark_bitmap == nullptr;
+ if (!is_los && mark_bitmap->Test(from_ref)) {
+ // Already marked.
+ to_ref = from_ref;
+ } else if (is_los && los_bitmap->Test(from_ref)) {
+ // Already marked in LOS.
+ to_ref = from_ref;
+ } else {
+ // Not marked.
+ if (IsOnAllocStack(from_ref)) {
+ // If on the allocation stack, it's considered marked.
+ to_ref = from_ref;
+ } else {
+ // Not marked.
+ to_ref = nullptr;
+ }
+ }
+ }
+ }
+ return to_ref;
+}
+
+bool ConcurrentCopying::IsOnAllocStack(mirror::Object* ref) {
+ QuasiAtomic::ThreadFenceAcquire();
+ accounting::ObjectStack* alloc_stack = GetAllocationStack();
+ mirror::Object** begin = alloc_stack->Begin();
+ // Important to read end once as it could be concurrently updated and screw up std::find().
+ mirror::Object** end = alloc_stack->End();
+ return std::find(begin, end, ref) != end;
+}
+
+mirror::Object* ConcurrentCopying::Mark(mirror::Object* from_ref) {
+ if (from_ref == nullptr) {
+ return nullptr;
+ }
+ DCHECK(from_ref != nullptr);
+ DCHECK(heap_->collector_type_ == kCollectorTypeCC);
+ if (region_space_->IsInToSpace(from_ref)) {
+ // It's already marked.
+ return from_ref;
+ }
+ mirror::Object* to_ref;
+ if (region_space_->IsInFromSpace(from_ref)) {
+ to_ref = GetFwdPtr(from_ref);
+ if (kUseBakerReadBarrier) {
+ DCHECK(to_ref != ReadBarrier::GrayPtr()) << "from_ref=" << from_ref << " to_ref=" << to_ref;
+ }
+ if (to_ref == nullptr) {
+ // It isn't marked yet. Mark it by copying it to the to-space.
+ to_ref = Copy(from_ref);
+ }
+ DCHECK(region_space_->IsInToSpace(to_ref) || heap_->non_moving_space_->HasAddress(to_ref))
+ << "from_ref=" << from_ref << " to_ref=" << to_ref;
+ } else if (region_space_->IsInUnevacFromSpace(from_ref)) {
+ // This may or may not succeed, which is ok.
+ if (kUseBakerReadBarrier) {
+ from_ref->AtomicSetReadBarrierPointer(ReadBarrier::WhitePtr(), ReadBarrier::GrayPtr());
+ }
+ if (region_space_bitmap_->AtomicTestAndSet(from_ref)) {
+ // Already marked.
+ to_ref = from_ref;
+ } else {
+ // Newly marked.
+ to_ref = from_ref;
+ if (kUseBakerReadBarrier) {
+ DCHECK(to_ref->GetReadBarrierPointer() == ReadBarrier::GrayPtr());
+ }
+ PushOntoMarkStack<true>(to_ref);
+ }
+ } else {
+ // from_ref is in a non-moving space.
+ DCHECK(!region_space_->HasAddress(from_ref)) << from_ref;
+ if (immune_region_.ContainsObject(from_ref)) {
+ accounting::ContinuousSpaceBitmap* cc_bitmap =
+ cc_heap_bitmap_->GetContinuousSpaceBitmap(from_ref);
+ DCHECK(cc_bitmap != nullptr)
+ << "An immune space object must have a bitmap";
+ if (kIsDebugBuild) {
+ DCHECK(heap_mark_bitmap_->GetContinuousSpaceBitmap(from_ref)->Test(from_ref))
+ << "Immune space object must be already marked";
+ }
+ // This may or may not succeed, which is ok.
+ if (kUseBakerReadBarrier) {
+ from_ref->AtomicSetReadBarrierPointer(ReadBarrier::WhitePtr(), ReadBarrier::GrayPtr());
+ }
+ if (cc_bitmap->AtomicTestAndSet(from_ref)) {
+ // Already marked.
+ to_ref = from_ref;
+ } else {
+ // Newly marked.
+ to_ref = from_ref;
+ if (kUseBakerReadBarrier) {
+ DCHECK(to_ref->GetReadBarrierPointer() == ReadBarrier::GrayPtr());
+ }
+ PushOntoMarkStack<true>(to_ref);
+ }
+ } else {
+ // Use the mark bitmap.
+ accounting::ContinuousSpaceBitmap* mark_bitmap =
+ heap_mark_bitmap_->GetContinuousSpaceBitmap(from_ref);
+ accounting::LargeObjectBitmap* los_bitmap =
+ heap_mark_bitmap_->GetLargeObjectBitmap(from_ref);
+ CHECK(los_bitmap != nullptr) << "LOS bitmap covers the entire address range";
+ bool is_los = mark_bitmap == nullptr;
+ if (!is_los && mark_bitmap->Test(from_ref)) {
+ // Already marked.
+ to_ref = from_ref;
+ if (kUseBakerReadBarrier) {
+ DCHECK(to_ref->GetReadBarrierPointer() == ReadBarrier::GrayPtr() ||
+ to_ref->GetReadBarrierPointer() == ReadBarrier::BlackPtr());
+ }
+ } else if (is_los && los_bitmap->Test(from_ref)) {
+ // Already marked in LOS.
+ to_ref = from_ref;
+ if (kUseBakerReadBarrier) {
+ DCHECK(to_ref->GetReadBarrierPointer() == ReadBarrier::GrayPtr() ||
+ to_ref->GetReadBarrierPointer() == ReadBarrier::BlackPtr());
+ }
+ } else {
+ // Not marked.
+ if (IsOnAllocStack(from_ref)) {
+ // If it's on the allocation stack, it's considered marked. Keep it white.
+ to_ref = from_ref;
+ // Objects on the allocation stack need not be marked.
+ if (!is_los) {
+ DCHECK(!mark_bitmap->Test(to_ref));
+ } else {
+ DCHECK(!los_bitmap->Test(to_ref));
+ }
+ if (kUseBakerReadBarrier) {
+ DCHECK(to_ref->GetReadBarrierPointer() == ReadBarrier::WhitePtr());
+ }
+ } else {
+ // Not marked or on the allocation stack. Try to mark it.
+ // This may or may not succeed, which is ok.
+ if (kUseBakerReadBarrier) {
+ from_ref->AtomicSetReadBarrierPointer(ReadBarrier::WhitePtr(), ReadBarrier::GrayPtr());
+ }
+ if (!is_los && mark_bitmap->AtomicTestAndSet(from_ref)) {
+ // Already marked.
+ to_ref = from_ref;
+ } else if (is_los && los_bitmap->AtomicTestAndSet(from_ref)) {
+ // Already marked in LOS.
+ to_ref = from_ref;
+ } else {
+ // Newly marked.
+ to_ref = from_ref;
+ if (kUseBakerReadBarrier) {
+ DCHECK(to_ref->GetReadBarrierPointer() == ReadBarrier::GrayPtr());
+ }
+ PushOntoMarkStack<true>(to_ref);
+ }
+ }
+ }
+ }
+ }
+ return to_ref;
+}
+
+void ConcurrentCopying::FinishPhase() {
+ region_space_ = nullptr;
+ CHECK(mark_queue_.IsEmpty());
+ mark_queue_.Clear();
+ {
+ MutexLock mu(Thread::Current(), skipped_blocks_lock_);
+ skipped_blocks_map_.clear();
+ }
+ WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_);
+ heap_->ClearMarkedObjects();
+}
+
+mirror::Object* ConcurrentCopying::IsMarkedCallback(mirror::Object* from_ref, void* arg) {
+ return reinterpret_cast<ConcurrentCopying*>(arg)->IsMarked(from_ref);
+}
+
+bool ConcurrentCopying::IsHeapReferenceMarkedCallback(
+ mirror::HeapReference<mirror::Object>* field, void* arg) {
+ mirror::Object* from_ref = field->AsMirrorPtr();
+ mirror::Object* to_ref = reinterpret_cast<ConcurrentCopying*>(arg)->IsMarked(from_ref);
+ if (to_ref == nullptr) {
+ return false;
+ }
+ if (from_ref != to_ref) {
+ QuasiAtomic::ThreadFenceRelease();
+ field->Assign(to_ref);
+ QuasiAtomic::ThreadFenceSequentiallyConsistent();
+ }
+ return true;
+}
+
+mirror::Object* ConcurrentCopying::MarkCallback(mirror::Object* from_ref, void* arg) {
+ return reinterpret_cast<ConcurrentCopying*>(arg)->Mark(from_ref);
+}
+
+void ConcurrentCopying::ProcessMarkStackCallback(void* arg) {
+ reinterpret_cast<ConcurrentCopying*>(arg)->ProcessMarkStack();
+}
+
+void ConcurrentCopying::DelayReferenceReferent(mirror::Class* klass, mirror::Reference* reference) {
+ heap_->GetReferenceProcessor()->DelayReferenceReferent(
+ klass, reference, &IsHeapReferenceMarkedCallback, this);
+}
+
+void ConcurrentCopying::ProcessReferences(Thread* self, bool concurrent) {
+ TimingLogger::ScopedTiming split("ProcessReferences", GetTimings());
+ WriterMutexLock mu(self, *Locks::heap_bitmap_lock_);
+ GetHeap()->GetReferenceProcessor()->ProcessReferences(
+ concurrent, GetTimings(), GetCurrentIteration()->GetClearSoftReferences(),
+ &IsHeapReferenceMarkedCallback, &MarkCallback, &ProcessMarkStackCallback, this);
+}
+
+void ConcurrentCopying::RevokeAllThreadLocalBuffers() {
+ TimingLogger::ScopedTiming t(__FUNCTION__, GetTimings());
+ region_space_->RevokeAllThreadLocalBuffers();
+}
+
} // namespace collector
} // namespace gc
} // namespace art