| // Copyright 2012 the V8 project authors. All rights reserved. |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following |
| // disclaimer in the documentation and/or other materials provided |
| // with the distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived |
| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #include "v8.h" |
| |
| #include "incremental-marking.h" |
| |
| #include "code-stubs.h" |
| #include "compilation-cache.h" |
| #include "objects-visiting.h" |
| #include "objects-visiting-inl.h" |
| #include "v8conversions.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| |
| IncrementalMarking::IncrementalMarking(Heap* heap) |
| : heap_(heap), |
| state_(STOPPED), |
| marking_deque_memory_(NULL), |
| marking_deque_memory_committed_(false), |
| steps_count_(0), |
| steps_took_(0), |
| longest_step_(0.0), |
| old_generation_space_available_at_start_of_incremental_(0), |
| old_generation_space_used_at_start_of_incremental_(0), |
| steps_count_since_last_gc_(0), |
| steps_took_since_last_gc_(0), |
| should_hurry_(false), |
| marking_speed_(0), |
| allocated_(0), |
| no_marking_scope_depth_(0), |
| unscanned_bytes_of_large_object_(0) { |
| } |
| |
| |
| void IncrementalMarking::TearDown() { |
| delete marking_deque_memory_; |
| } |
| |
| |
| void IncrementalMarking::RecordWriteSlow(HeapObject* obj, |
| Object** slot, |
| Object* value) { |
| if (BaseRecordWrite(obj, slot, value) && slot != NULL) { |
| MarkBit obj_bit = Marking::MarkBitFrom(obj); |
| if (Marking::IsBlack(obj_bit)) { |
| // Object is not going to be rescanned we need to record the slot. |
| heap_->mark_compact_collector()->RecordSlot( |
| HeapObject::RawField(obj, 0), slot, value); |
| } |
| } |
| } |
| |
| |
| void IncrementalMarking::RecordWriteFromCode(HeapObject* obj, |
| Object** slot, |
| Isolate* isolate) { |
| ASSERT(obj->IsHeapObject()); |
| IncrementalMarking* marking = isolate->heap()->incremental_marking(); |
| ASSERT(!marking->is_compacting_); |
| |
| MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address()); |
| int counter = chunk->write_barrier_counter(); |
| if (counter < (MemoryChunk::kWriteBarrierCounterGranularity / 2)) { |
| marking->write_barriers_invoked_since_last_step_ += |
| MemoryChunk::kWriteBarrierCounterGranularity - |
| chunk->write_barrier_counter(); |
| chunk->set_write_barrier_counter( |
| MemoryChunk::kWriteBarrierCounterGranularity); |
| } |
| |
| marking->RecordWrite(obj, slot, *slot); |
| } |
| |
| |
| void IncrementalMarking::RecordWriteForEvacuationFromCode(HeapObject* obj, |
| Object** slot, |
| Isolate* isolate) { |
| ASSERT(obj->IsHeapObject()); |
| IncrementalMarking* marking = isolate->heap()->incremental_marking(); |
| ASSERT(marking->is_compacting_); |
| |
| MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address()); |
| int counter = chunk->write_barrier_counter(); |
| if (counter < (MemoryChunk::kWriteBarrierCounterGranularity / 2)) { |
| marking->write_barriers_invoked_since_last_step_ += |
| MemoryChunk::kWriteBarrierCounterGranularity - |
| chunk->write_barrier_counter(); |
| chunk->set_write_barrier_counter( |
| MemoryChunk::kWriteBarrierCounterGranularity); |
| } |
| |
| marking->RecordWrite(obj, slot, *slot); |
| } |
| |
| |
| void IncrementalMarking::RecordCodeTargetPatch(Code* host, |
| Address pc, |
| HeapObject* value) { |
| if (IsMarking()) { |
| RelocInfo rinfo(pc, RelocInfo::CODE_TARGET, 0, host); |
| RecordWriteIntoCode(host, &rinfo, value); |
| } |
| } |
| |
| |
| void IncrementalMarking::RecordCodeTargetPatch(Address pc, HeapObject* value) { |
| if (IsMarking()) { |
| Code* host = heap_->isolate()->inner_pointer_to_code_cache()-> |
| GcSafeFindCodeForInnerPointer(pc); |
| RelocInfo rinfo(pc, RelocInfo::CODE_TARGET, 0, host); |
| RecordWriteIntoCode(host, &rinfo, value); |
| } |
| } |
| |
| |
| void IncrementalMarking::RecordWriteOfCodeEntrySlow(JSFunction* host, |
| Object** slot, |
| Code* value) { |
| if (BaseRecordWrite(host, slot, value)) { |
| ASSERT(slot != NULL); |
| heap_->mark_compact_collector()-> |
| RecordCodeEntrySlot(reinterpret_cast<Address>(slot), value); |
| } |
| } |
| |
| |
| void IncrementalMarking::RecordWriteIntoCodeSlow(HeapObject* obj, |
| RelocInfo* rinfo, |
| Object* value) { |
| MarkBit value_bit = Marking::MarkBitFrom(HeapObject::cast(value)); |
| if (Marking::IsWhite(value_bit)) { |
| MarkBit obj_bit = Marking::MarkBitFrom(obj); |
| if (Marking::IsBlack(obj_bit)) { |
| BlackToGreyAndUnshift(obj, obj_bit); |
| RestartIfNotMarking(); |
| } |
| // Object is either grey or white. It will be scanned if survives. |
| return; |
| } |
| |
| if (is_compacting_) { |
| MarkBit obj_bit = Marking::MarkBitFrom(obj); |
| if (Marking::IsBlack(obj_bit)) { |
| // Object is not going to be rescanned. We need to record the slot. |
| heap_->mark_compact_collector()->RecordRelocSlot(rinfo, |
| Code::cast(value)); |
| } |
| } |
| } |
| |
| |
| static void MarkObjectGreyDoNotEnqueue(Object* obj) { |
| if (obj->IsHeapObject()) { |
| HeapObject* heap_obj = HeapObject::cast(obj); |
| MarkBit mark_bit = Marking::MarkBitFrom(HeapObject::cast(obj)); |
| if (Marking::IsBlack(mark_bit)) { |
| MemoryChunk::IncrementLiveBytesFromGC(heap_obj->address(), |
| -heap_obj->Size()); |
| } |
| Marking::AnyToGrey(mark_bit); |
| } |
| } |
| |
| |
| static inline void MarkBlackOrKeepGrey(HeapObject* heap_object, |
| MarkBit mark_bit, |
| int size) { |
| ASSERT(!Marking::IsImpossible(mark_bit)); |
| if (mark_bit.Get()) return; |
| mark_bit.Set(); |
| MemoryChunk::IncrementLiveBytesFromGC(heap_object->address(), size); |
| ASSERT(Marking::IsBlack(mark_bit)); |
| } |
| |
| |
| static inline void MarkBlackOrKeepBlack(HeapObject* heap_object, |
| MarkBit mark_bit, |
| int size) { |
| ASSERT(!Marking::IsImpossible(mark_bit)); |
| if (Marking::IsBlack(mark_bit)) return; |
| Marking::MarkBlack(mark_bit); |
| MemoryChunk::IncrementLiveBytesFromGC(heap_object->address(), size); |
| ASSERT(Marking::IsBlack(mark_bit)); |
| } |
| |
| |
| class IncrementalMarkingMarkingVisitor |
| : public StaticMarkingVisitor<IncrementalMarkingMarkingVisitor> { |
| public: |
| static void Initialize() { |
| StaticMarkingVisitor<IncrementalMarkingMarkingVisitor>::Initialize(); |
| table_.Register(kVisitFixedArray, &VisitFixedArrayIncremental); |
| table_.Register(kVisitNativeContext, &VisitNativeContextIncremental); |
| table_.Register(kVisitJSRegExp, &VisitJSRegExp); |
| } |
| |
| static const int kProgressBarScanningChunk = 32 * 1024; |
| |
| static void VisitFixedArrayIncremental(Map* map, HeapObject* object) { |
| MemoryChunk* chunk = MemoryChunk::FromAddress(object->address()); |
| // TODO(mstarzinger): Move setting of the flag to the allocation site of |
| // the array. The visitor should just check the flag. |
| if (FLAG_use_marking_progress_bar && |
| chunk->owner()->identity() == LO_SPACE) { |
| chunk->SetFlag(MemoryChunk::HAS_PROGRESS_BAR); |
| } |
| if (chunk->IsFlagSet(MemoryChunk::HAS_PROGRESS_BAR)) { |
| Heap* heap = map->GetHeap(); |
| // When using a progress bar for large fixed arrays, scan only a chunk of |
| // the array and try to push it onto the marking deque again until it is |
| // fully scanned. Fall back to scanning it through to the end in case this |
| // fails because of a full deque. |
| int object_size = FixedArray::BodyDescriptor::SizeOf(map, object); |
| int start_offset = Max(FixedArray::BodyDescriptor::kStartOffset, |
| chunk->progress_bar()); |
| int end_offset = Min(object_size, |
| start_offset + kProgressBarScanningChunk); |
| int already_scanned_offset = start_offset; |
| bool scan_until_end = false; |
| do { |
| VisitPointersWithAnchor(heap, |
| HeapObject::RawField(object, 0), |
| HeapObject::RawField(object, start_offset), |
| HeapObject::RawField(object, end_offset)); |
| start_offset = end_offset; |
| end_offset = Min(object_size, end_offset + kProgressBarScanningChunk); |
| scan_until_end = heap->incremental_marking()->marking_deque()->IsFull(); |
| } while (scan_until_end && start_offset < object_size); |
| chunk->set_progress_bar(start_offset); |
| if (start_offset < object_size) { |
| heap->incremental_marking()->marking_deque()->UnshiftGrey(object); |
| heap->incremental_marking()->NotifyIncompleteScanOfObject( |
| object_size - (start_offset - already_scanned_offset)); |
| } |
| } else { |
| FixedArrayVisitor::Visit(map, object); |
| } |
| } |
| |
| static void VisitNativeContextIncremental(Map* map, HeapObject* object) { |
| Context* context = Context::cast(object); |
| |
| // We will mark cache black with a separate pass |
| // when we finish marking. |
| MarkObjectGreyDoNotEnqueue(context->normalized_map_cache()); |
| VisitNativeContext(map, context); |
| } |
| |
| static void VisitWeakCollection(Map* map, HeapObject* object) { |
| Heap* heap = map->GetHeap(); |
| VisitPointers(heap, |
| HeapObject::RawField(object, |
| JSWeakCollection::kPropertiesOffset), |
| HeapObject::RawField(object, JSWeakCollection::kSize)); |
| } |
| |
| static void BeforeVisitingSharedFunctionInfo(HeapObject* object) {} |
| |
| INLINE(static void VisitPointer(Heap* heap, Object** p)) { |
| Object* obj = *p; |
| if (obj->NonFailureIsHeapObject()) { |
| heap->mark_compact_collector()->RecordSlot(p, p, obj); |
| MarkObject(heap, obj); |
| } |
| } |
| |
| INLINE(static void VisitPointers(Heap* heap, Object** start, Object** end)) { |
| for (Object** p = start; p < end; p++) { |
| Object* obj = *p; |
| if (obj->NonFailureIsHeapObject()) { |
| heap->mark_compact_collector()->RecordSlot(start, p, obj); |
| MarkObject(heap, obj); |
| } |
| } |
| } |
| |
| INLINE(static void VisitPointersWithAnchor(Heap* heap, |
| Object** anchor, |
| Object** start, |
| Object** end)) { |
| for (Object** p = start; p < end; p++) { |
| Object* obj = *p; |
| if (obj->NonFailureIsHeapObject()) { |
| heap->mark_compact_collector()->RecordSlot(anchor, p, obj); |
| MarkObject(heap, obj); |
| } |
| } |
| } |
| |
| // Marks the object grey and pushes it on the marking stack. |
| INLINE(static void MarkObject(Heap* heap, Object* obj)) { |
| HeapObject* heap_object = HeapObject::cast(obj); |
| MarkBit mark_bit = Marking::MarkBitFrom(heap_object); |
| if (mark_bit.data_only()) { |
| MarkBlackOrKeepGrey(heap_object, mark_bit, heap_object->Size()); |
| } else if (Marking::IsWhite(mark_bit)) { |
| heap->incremental_marking()->WhiteToGreyAndPush(heap_object, mark_bit); |
| } |
| } |
| |
| // Marks the object black without pushing it on the marking stack. |
| // Returns true if object needed marking and false otherwise. |
| INLINE(static bool MarkObjectWithoutPush(Heap* heap, Object* obj)) { |
| HeapObject* heap_object = HeapObject::cast(obj); |
| MarkBit mark_bit = Marking::MarkBitFrom(heap_object); |
| if (Marking::IsWhite(mark_bit)) { |
| mark_bit.Set(); |
| MemoryChunk::IncrementLiveBytesFromGC(heap_object->address(), |
| heap_object->Size()); |
| return true; |
| } |
| return false; |
| } |
| }; |
| |
| |
| class IncrementalMarkingRootMarkingVisitor : public ObjectVisitor { |
| public: |
| explicit IncrementalMarkingRootMarkingVisitor( |
| IncrementalMarking* incremental_marking) |
| : incremental_marking_(incremental_marking) { |
| } |
| |
| void VisitPointer(Object** p) { |
| MarkObjectByPointer(p); |
| } |
| |
| void VisitPointers(Object** start, Object** end) { |
| for (Object** p = start; p < end; p++) MarkObjectByPointer(p); |
| } |
| |
| private: |
| void MarkObjectByPointer(Object** p) { |
| Object* obj = *p; |
| if (!obj->IsHeapObject()) return; |
| |
| HeapObject* heap_object = HeapObject::cast(obj); |
| MarkBit mark_bit = Marking::MarkBitFrom(heap_object); |
| if (mark_bit.data_only()) { |
| MarkBlackOrKeepGrey(heap_object, mark_bit, heap_object->Size()); |
| } else { |
| if (Marking::IsWhite(mark_bit)) { |
| incremental_marking_->WhiteToGreyAndPush(heap_object, mark_bit); |
| } |
| } |
| } |
| |
| IncrementalMarking* incremental_marking_; |
| }; |
| |
| |
| void IncrementalMarking::Initialize() { |
| IncrementalMarkingMarkingVisitor::Initialize(); |
| } |
| |
| |
| void IncrementalMarking::SetOldSpacePageFlags(MemoryChunk* chunk, |
| bool is_marking, |
| bool is_compacting) { |
| if (is_marking) { |
| chunk->SetFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING); |
| chunk->SetFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING); |
| |
| // It's difficult to filter out slots recorded for large objects. |
| if (chunk->owner()->identity() == LO_SPACE && |
| chunk->size() > static_cast<size_t>(Page::kPageSize) && |
| is_compacting) { |
| chunk->SetFlag(MemoryChunk::RESCAN_ON_EVACUATION); |
| } |
| } else if (chunk->owner()->identity() == CELL_SPACE || |
| chunk->owner()->identity() == PROPERTY_CELL_SPACE || |
| chunk->scan_on_scavenge()) { |
| chunk->ClearFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING); |
| chunk->ClearFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING); |
| } else { |
| chunk->ClearFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING); |
| chunk->SetFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING); |
| } |
| } |
| |
| |
| void IncrementalMarking::SetNewSpacePageFlags(NewSpacePage* chunk, |
| bool is_marking) { |
| chunk->SetFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING); |
| if (is_marking) { |
| chunk->SetFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING); |
| } else { |
| chunk->ClearFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING); |
| } |
| chunk->SetFlag(MemoryChunk::SCAN_ON_SCAVENGE); |
| } |
| |
| |
| void IncrementalMarking::DeactivateIncrementalWriteBarrierForSpace( |
| PagedSpace* space) { |
| PageIterator it(space); |
| while (it.has_next()) { |
| Page* p = it.next(); |
| SetOldSpacePageFlags(p, false, false); |
| } |
| } |
| |
| |
| void IncrementalMarking::DeactivateIncrementalWriteBarrierForSpace( |
| NewSpace* space) { |
| NewSpacePageIterator it(space); |
| while (it.has_next()) { |
| NewSpacePage* p = it.next(); |
| SetNewSpacePageFlags(p, false); |
| } |
| } |
| |
| |
| void IncrementalMarking::DeactivateIncrementalWriteBarrier() { |
| DeactivateIncrementalWriteBarrierForSpace(heap_->old_pointer_space()); |
| DeactivateIncrementalWriteBarrierForSpace(heap_->old_data_space()); |
| DeactivateIncrementalWriteBarrierForSpace(heap_->cell_space()); |
| DeactivateIncrementalWriteBarrierForSpace(heap_->property_cell_space()); |
| DeactivateIncrementalWriteBarrierForSpace(heap_->map_space()); |
| DeactivateIncrementalWriteBarrierForSpace(heap_->code_space()); |
| DeactivateIncrementalWriteBarrierForSpace(heap_->new_space()); |
| |
| LargePage* lop = heap_->lo_space()->first_page(); |
| while (lop->is_valid()) { |
| SetOldSpacePageFlags(lop, false, false); |
| lop = lop->next_page(); |
| } |
| } |
| |
| |
| void IncrementalMarking::ActivateIncrementalWriteBarrier(PagedSpace* space) { |
| PageIterator it(space); |
| while (it.has_next()) { |
| Page* p = it.next(); |
| SetOldSpacePageFlags(p, true, is_compacting_); |
| } |
| } |
| |
| |
| void IncrementalMarking::ActivateIncrementalWriteBarrier(NewSpace* space) { |
| NewSpacePageIterator it(space->ToSpaceStart(), space->ToSpaceEnd()); |
| while (it.has_next()) { |
| NewSpacePage* p = it.next(); |
| SetNewSpacePageFlags(p, true); |
| } |
| } |
| |
| |
| void IncrementalMarking::ActivateIncrementalWriteBarrier() { |
| ActivateIncrementalWriteBarrier(heap_->old_pointer_space()); |
| ActivateIncrementalWriteBarrier(heap_->old_data_space()); |
| ActivateIncrementalWriteBarrier(heap_->cell_space()); |
| ActivateIncrementalWriteBarrier(heap_->property_cell_space()); |
| ActivateIncrementalWriteBarrier(heap_->map_space()); |
| ActivateIncrementalWriteBarrier(heap_->code_space()); |
| ActivateIncrementalWriteBarrier(heap_->new_space()); |
| |
| LargePage* lop = heap_->lo_space()->first_page(); |
| while (lop->is_valid()) { |
| SetOldSpacePageFlags(lop, true, is_compacting_); |
| lop = lop->next_page(); |
| } |
| } |
| |
| |
| bool IncrementalMarking::WorthActivating() { |
| #ifndef DEBUG |
| static const intptr_t kActivationThreshold = 8 * MB; |
| #else |
| // TODO(gc) consider setting this to some low level so that some |
| // debug tests run with incremental marking and some without. |
| static const intptr_t kActivationThreshold = 0; |
| #endif |
| // Only start incremental marking in a safe state: 1) when expose GC is |
| // deactivated, 2) when incremental marking is turned on, 3) when we are |
| // currently not in a GC, and 4) when we are currently not serializing |
| // or deserializing the heap. |
| return !FLAG_expose_gc && |
| FLAG_incremental_marking && |
| FLAG_incremental_marking_steps && |
| heap_->gc_state() == Heap::NOT_IN_GC && |
| !Serializer::enabled() && |
| heap_->isolate()->IsInitialized() && |
| heap_->PromotedSpaceSizeOfObjects() > kActivationThreshold; |
| } |
| |
| |
| void IncrementalMarking::ActivateGeneratedStub(Code* stub) { |
| ASSERT(RecordWriteStub::GetMode(stub) == |
| RecordWriteStub::STORE_BUFFER_ONLY); |
| |
| if (!IsMarking()) { |
| // Initially stub is generated in STORE_BUFFER_ONLY mode thus |
| // we don't need to do anything if incremental marking is |
| // not active. |
| } else if (IsCompacting()) { |
| RecordWriteStub::Patch(stub, RecordWriteStub::INCREMENTAL_COMPACTION); |
| } else { |
| RecordWriteStub::Patch(stub, RecordWriteStub::INCREMENTAL); |
| } |
| } |
| |
| |
| static void PatchIncrementalMarkingRecordWriteStubs( |
| Heap* heap, RecordWriteStub::Mode mode) { |
| UnseededNumberDictionary* stubs = heap->code_stubs(); |
| |
| int capacity = stubs->Capacity(); |
| for (int i = 0; i < capacity; i++) { |
| Object* k = stubs->KeyAt(i); |
| if (stubs->IsKey(k)) { |
| uint32_t key = NumberToUint32(k); |
| |
| if (CodeStub::MajorKeyFromKey(key) == |
| CodeStub::RecordWrite) { |
| Object* e = stubs->ValueAt(i); |
| if (e->IsCode()) { |
| RecordWriteStub::Patch(Code::cast(e), mode); |
| } |
| } |
| } |
| } |
| } |
| |
| |
| void IncrementalMarking::EnsureMarkingDequeIsCommitted() { |
| if (marking_deque_memory_ == NULL) { |
| marking_deque_memory_ = new VirtualMemory(4 * MB); |
| } |
| if (!marking_deque_memory_committed_) { |
| bool success = marking_deque_memory_->Commit( |
| reinterpret_cast<Address>(marking_deque_memory_->address()), |
| marking_deque_memory_->size(), |
| false); // Not executable. |
| CHECK(success); |
| marking_deque_memory_committed_ = true; |
| } |
| } |
| |
| |
| void IncrementalMarking::UncommitMarkingDeque() { |
| if (state_ == STOPPED && marking_deque_memory_committed_) { |
| bool success = marking_deque_memory_->Uncommit( |
| reinterpret_cast<Address>(marking_deque_memory_->address()), |
| marking_deque_memory_->size()); |
| CHECK(success); |
| marking_deque_memory_committed_ = false; |
| } |
| } |
| |
| |
| void IncrementalMarking::Start(CompactionFlag flag) { |
| if (FLAG_trace_incremental_marking) { |
| PrintF("[IncrementalMarking] Start\n"); |
| } |
| ASSERT(FLAG_incremental_marking); |
| ASSERT(FLAG_incremental_marking_steps); |
| ASSERT(state_ == STOPPED); |
| ASSERT(heap_->gc_state() == Heap::NOT_IN_GC); |
| ASSERT(!Serializer::enabled()); |
| ASSERT(heap_->isolate()->IsInitialized()); |
| |
| ResetStepCounters(); |
| |
| if (heap_->IsSweepingComplete()) { |
| StartMarking(flag); |
| } else { |
| if (FLAG_trace_incremental_marking) { |
| PrintF("[IncrementalMarking] Start sweeping.\n"); |
| } |
| state_ = SWEEPING; |
| } |
| |
| heap_->new_space()->LowerInlineAllocationLimit(kAllocatedThreshold); |
| } |
| |
| |
| void IncrementalMarking::StartMarking(CompactionFlag flag) { |
| if (FLAG_trace_incremental_marking) { |
| PrintF("[IncrementalMarking] Start marking\n"); |
| } |
| |
| is_compacting_ = !FLAG_never_compact && (flag == ALLOW_COMPACTION) && |
| heap_->mark_compact_collector()->StartCompaction( |
| MarkCompactCollector::INCREMENTAL_COMPACTION); |
| |
| state_ = MARKING; |
| |
| RecordWriteStub::Mode mode = is_compacting_ ? |
| RecordWriteStub::INCREMENTAL_COMPACTION : RecordWriteStub::INCREMENTAL; |
| |
| PatchIncrementalMarkingRecordWriteStubs(heap_, mode); |
| |
| EnsureMarkingDequeIsCommitted(); |
| |
| // Initialize marking stack. |
| Address addr = static_cast<Address>(marking_deque_memory_->address()); |
| size_t size = marking_deque_memory_->size(); |
| if (FLAG_force_marking_deque_overflows) size = 64 * kPointerSize; |
| marking_deque_.Initialize(addr, addr + size); |
| |
| ActivateIncrementalWriteBarrier(); |
| |
| // Marking bits are cleared by the sweeper. |
| #ifdef VERIFY_HEAP |
| if (FLAG_verify_heap) { |
| heap_->mark_compact_collector()->VerifyMarkbitsAreClean(); |
| } |
| #endif |
| |
| heap_->CompletelyClearInstanceofCache(); |
| heap_->isolate()->compilation_cache()->MarkCompactPrologue(); |
| |
| if (FLAG_cleanup_code_caches_at_gc) { |
| // We will mark cache black with a separate pass |
| // when we finish marking. |
| MarkObjectGreyDoNotEnqueue(heap_->polymorphic_code_cache()); |
| } |
| |
| // Mark strong roots grey. |
| IncrementalMarkingRootMarkingVisitor visitor(this); |
| heap_->IterateStrongRoots(&visitor, VISIT_ONLY_STRONG); |
| |
| heap_->mark_compact_collector()->MarkWeakObjectToCodeTable(); |
| |
| // Ready to start incremental marking. |
| if (FLAG_trace_incremental_marking) { |
| PrintF("[IncrementalMarking] Running\n"); |
| } |
| } |
| |
| |
| void IncrementalMarking::PrepareForScavenge() { |
| if (!IsMarking()) return; |
| NewSpacePageIterator it(heap_->new_space()->FromSpaceStart(), |
| heap_->new_space()->FromSpaceEnd()); |
| while (it.has_next()) { |
| Bitmap::Clear(it.next()); |
| } |
| } |
| |
| |
| void IncrementalMarking::UpdateMarkingDequeAfterScavenge() { |
| if (!IsMarking()) return; |
| |
| int current = marking_deque_.bottom(); |
| int mask = marking_deque_.mask(); |
| int limit = marking_deque_.top(); |
| HeapObject** array = marking_deque_.array(); |
| int new_top = current; |
| |
| Map* filler_map = heap_->one_pointer_filler_map(); |
| |
| while (current != limit) { |
| HeapObject* obj = array[current]; |
| ASSERT(obj->IsHeapObject()); |
| current = ((current + 1) & mask); |
| if (heap_->InNewSpace(obj)) { |
| MapWord map_word = obj->map_word(); |
| if (map_word.IsForwardingAddress()) { |
| HeapObject* dest = map_word.ToForwardingAddress(); |
| array[new_top] = dest; |
| new_top = ((new_top + 1) & mask); |
| ASSERT(new_top != marking_deque_.bottom()); |
| #ifdef DEBUG |
| MarkBit mark_bit = Marking::MarkBitFrom(obj); |
| ASSERT(Marking::IsGrey(mark_bit) || |
| (obj->IsFiller() && Marking::IsWhite(mark_bit))); |
| #endif |
| } |
| } else if (obj->map() != filler_map) { |
| // Skip one word filler objects that appear on the |
| // stack when we perform in place array shift. |
| array[new_top] = obj; |
| new_top = ((new_top + 1) & mask); |
| ASSERT(new_top != marking_deque_.bottom()); |
| #ifdef DEBUG |
| MarkBit mark_bit = Marking::MarkBitFrom(obj); |
| MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address()); |
| ASSERT(Marking::IsGrey(mark_bit) || |
| (obj->IsFiller() && Marking::IsWhite(mark_bit)) || |
| (chunk->IsFlagSet(MemoryChunk::HAS_PROGRESS_BAR) && |
| Marking::IsBlack(mark_bit))); |
| #endif |
| } |
| } |
| marking_deque_.set_top(new_top); |
| |
| steps_took_since_last_gc_ = 0; |
| steps_count_since_last_gc_ = 0; |
| longest_step_ = 0.0; |
| } |
| |
| |
| void IncrementalMarking::VisitObject(Map* map, HeapObject* obj, int size) { |
| MarkBit map_mark_bit = Marking::MarkBitFrom(map); |
| if (Marking::IsWhite(map_mark_bit)) { |
| WhiteToGreyAndPush(map, map_mark_bit); |
| } |
| |
| IncrementalMarkingMarkingVisitor::IterateBody(map, obj); |
| |
| MarkBit mark_bit = Marking::MarkBitFrom(obj); |
| #if ENABLE_SLOW_ASSERTS |
| MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address()); |
| SLOW_ASSERT(Marking::IsGrey(mark_bit) || |
| (obj->IsFiller() && Marking::IsWhite(mark_bit)) || |
| (chunk->IsFlagSet(MemoryChunk::HAS_PROGRESS_BAR) && |
| Marking::IsBlack(mark_bit))); |
| #endif |
| MarkBlackOrKeepBlack(obj, mark_bit, size); |
| } |
| |
| |
| void IncrementalMarking::ProcessMarkingDeque(intptr_t bytes_to_process) { |
| Map* filler_map = heap_->one_pointer_filler_map(); |
| while (!marking_deque_.IsEmpty() && bytes_to_process > 0) { |
| HeapObject* obj = marking_deque_.Pop(); |
| |
| // Explicitly skip one word fillers. Incremental markbit patterns are |
| // correct only for objects that occupy at least two words. |
| Map* map = obj->map(); |
| if (map == filler_map) continue; |
| |
| int size = obj->SizeFromMap(map); |
| unscanned_bytes_of_large_object_ = 0; |
| VisitObject(map, obj, size); |
| bytes_to_process -= (size - unscanned_bytes_of_large_object_); |
| } |
| } |
| |
| |
| void IncrementalMarking::ProcessMarkingDeque() { |
| Map* filler_map = heap_->one_pointer_filler_map(); |
| while (!marking_deque_.IsEmpty()) { |
| HeapObject* obj = marking_deque_.Pop(); |
| |
| // Explicitly skip one word fillers. Incremental markbit patterns are |
| // correct only for objects that occupy at least two words. |
| Map* map = obj->map(); |
| if (map == filler_map) continue; |
| |
| VisitObject(map, obj, obj->SizeFromMap(map)); |
| } |
| } |
| |
| |
| void IncrementalMarking::Hurry() { |
| if (state() == MARKING) { |
| double start = 0.0; |
| if (FLAG_trace_incremental_marking || FLAG_print_cumulative_gc_stat) { |
| start = OS::TimeCurrentMillis(); |
| if (FLAG_trace_incremental_marking) { |
| PrintF("[IncrementalMarking] Hurry\n"); |
| } |
| } |
| // TODO(gc) hurry can mark objects it encounters black as mutator |
| // was stopped. |
| ProcessMarkingDeque(); |
| state_ = COMPLETE; |
| if (FLAG_trace_incremental_marking || FLAG_print_cumulative_gc_stat) { |
| double end = OS::TimeCurrentMillis(); |
| double delta = end - start; |
| heap_->AddMarkingTime(delta); |
| if (FLAG_trace_incremental_marking) { |
| PrintF("[IncrementalMarking] Complete (hurry), spent %d ms.\n", |
| static_cast<int>(delta)); |
| } |
| } |
| } |
| |
| if (FLAG_cleanup_code_caches_at_gc) { |
| PolymorphicCodeCache* poly_cache = heap_->polymorphic_code_cache(); |
| Marking::GreyToBlack(Marking::MarkBitFrom(poly_cache)); |
| MemoryChunk::IncrementLiveBytesFromGC(poly_cache->address(), |
| PolymorphicCodeCache::kSize); |
| } |
| |
| Object* context = heap_->native_contexts_list(); |
| while (!context->IsUndefined()) { |
| // GC can happen when the context is not fully initialized, |
| // so the cache can be undefined. |
| HeapObject* cache = HeapObject::cast( |
| Context::cast(context)->get(Context::NORMALIZED_MAP_CACHE_INDEX)); |
| if (!cache->IsUndefined()) { |
| MarkBit mark_bit = Marking::MarkBitFrom(cache); |
| if (Marking::IsGrey(mark_bit)) { |
| Marking::GreyToBlack(mark_bit); |
| MemoryChunk::IncrementLiveBytesFromGC(cache->address(), cache->Size()); |
| } |
| } |
| context = Context::cast(context)->get(Context::NEXT_CONTEXT_LINK); |
| } |
| } |
| |
| |
| void IncrementalMarking::Abort() { |
| if (IsStopped()) return; |
| if (FLAG_trace_incremental_marking) { |
| PrintF("[IncrementalMarking] Aborting.\n"); |
| } |
| heap_->new_space()->LowerInlineAllocationLimit(0); |
| IncrementalMarking::set_should_hurry(false); |
| ResetStepCounters(); |
| if (IsMarking()) { |
| PatchIncrementalMarkingRecordWriteStubs(heap_, |
| RecordWriteStub::STORE_BUFFER_ONLY); |
| DeactivateIncrementalWriteBarrier(); |
| |
| if (is_compacting_) { |
| LargeObjectIterator it(heap_->lo_space()); |
| for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) { |
| Page* p = Page::FromAddress(obj->address()); |
| if (p->IsFlagSet(Page::RESCAN_ON_EVACUATION)) { |
| p->ClearFlag(Page::RESCAN_ON_EVACUATION); |
| } |
| } |
| } |
| } |
| heap_->isolate()->stack_guard()->Continue(GC_REQUEST); |
| state_ = STOPPED; |
| is_compacting_ = false; |
| } |
| |
| |
| void IncrementalMarking::Finalize() { |
| Hurry(); |
| state_ = STOPPED; |
| is_compacting_ = false; |
| heap_->new_space()->LowerInlineAllocationLimit(0); |
| IncrementalMarking::set_should_hurry(false); |
| ResetStepCounters(); |
| PatchIncrementalMarkingRecordWriteStubs(heap_, |
| RecordWriteStub::STORE_BUFFER_ONLY); |
| DeactivateIncrementalWriteBarrier(); |
| ASSERT(marking_deque_.IsEmpty()); |
| heap_->isolate()->stack_guard()->Continue(GC_REQUEST); |
| } |
| |
| |
| void IncrementalMarking::MarkingComplete(CompletionAction action) { |
| state_ = COMPLETE; |
| // We will set the stack guard to request a GC now. This will mean the rest |
| // of the GC gets performed as soon as possible (we can't do a GC here in a |
| // record-write context). If a few things get allocated between now and then |
| // that shouldn't make us do a scavenge and keep being incremental, so we set |
| // the should-hurry flag to indicate that there can't be much work left to do. |
| set_should_hurry(true); |
| if (FLAG_trace_incremental_marking) { |
| PrintF("[IncrementalMarking] Complete (normal).\n"); |
| } |
| if (action == GC_VIA_STACK_GUARD) { |
| heap_->isolate()->stack_guard()->RequestGC(); |
| } |
| } |
| |
| |
| void IncrementalMarking::OldSpaceStep(intptr_t allocated) { |
| if (IsStopped() && WorthActivating() && heap_->NextGCIsLikelyToBeFull()) { |
| // TODO(hpayer): Let's play safe for now, but compaction should be |
| // in principle possible. |
| Start(PREVENT_COMPACTION); |
| } else { |
| Step(allocated * kFastMarking / kInitialMarkingSpeed, GC_VIA_STACK_GUARD); |
| } |
| } |
| |
| |
| void IncrementalMarking::Step(intptr_t allocated_bytes, |
| CompletionAction action) { |
| if (heap_->gc_state() != Heap::NOT_IN_GC || |
| !FLAG_incremental_marking || |
| !FLAG_incremental_marking_steps || |
| (state_ != SWEEPING && state_ != MARKING)) { |
| return; |
| } |
| |
| allocated_ += allocated_bytes; |
| |
| if (allocated_ < kAllocatedThreshold && |
| write_barriers_invoked_since_last_step_ < |
| kWriteBarriersInvokedThreshold) { |
| return; |
| } |
| |
| if (state_ == MARKING && no_marking_scope_depth_ > 0) return; |
| |
| // The marking speed is driven either by the allocation rate or by the rate |
| // at which we are having to check the color of objects in the write barrier. |
| // It is possible for a tight non-allocating loop to run a lot of write |
| // barriers before we get here and check them (marking can only take place on |
| // allocation), so to reduce the lumpiness we don't use the write barriers |
| // invoked since last step directly to determine the amount of work to do. |
| intptr_t bytes_to_process = |
| marking_speed_ * Max(allocated_, write_barriers_invoked_since_last_step_); |
| allocated_ = 0; |
| write_barriers_invoked_since_last_step_ = 0; |
| |
| bytes_scanned_ += bytes_to_process; |
| |
| double start = 0; |
| |
| if (FLAG_trace_incremental_marking || FLAG_trace_gc || |
| FLAG_print_cumulative_gc_stat) { |
| start = OS::TimeCurrentMillis(); |
| } |
| |
| if (state_ == SWEEPING) { |
| if (heap_->EnsureSweepersProgressed(static_cast<int>(bytes_to_process))) { |
| bytes_scanned_ = 0; |
| StartMarking(PREVENT_COMPACTION); |
| } |
| } else if (state_ == MARKING) { |
| ProcessMarkingDeque(bytes_to_process); |
| if (marking_deque_.IsEmpty()) MarkingComplete(action); |
| } |
| |
| steps_count_++; |
| steps_count_since_last_gc_++; |
| |
| bool speed_up = false; |
| |
| if ((steps_count_ % kMarkingSpeedAccellerationInterval) == 0) { |
| if (FLAG_trace_gc) { |
| PrintPID("Speed up marking after %d steps\n", |
| static_cast<int>(kMarkingSpeedAccellerationInterval)); |
| } |
| speed_up = true; |
| } |
| |
| bool space_left_is_very_small = |
| (old_generation_space_available_at_start_of_incremental_ < 10 * MB); |
| |
| bool only_1_nth_of_space_that_was_available_still_left = |
| (SpaceLeftInOldSpace() * (marking_speed_ + 1) < |
| old_generation_space_available_at_start_of_incremental_); |
| |
| if (space_left_is_very_small || |
| only_1_nth_of_space_that_was_available_still_left) { |
| if (FLAG_trace_gc) PrintPID("Speed up marking because of low space left\n"); |
| speed_up = true; |
| } |
| |
| bool size_of_old_space_multiplied_by_n_during_marking = |
| (heap_->PromotedTotalSize() > |
| (marking_speed_ + 1) * |
| old_generation_space_used_at_start_of_incremental_); |
| if (size_of_old_space_multiplied_by_n_during_marking) { |
| speed_up = true; |
| if (FLAG_trace_gc) { |
| PrintPID("Speed up marking because of heap size increase\n"); |
| } |
| } |
| |
| int64_t promoted_during_marking = heap_->PromotedTotalSize() |
| - old_generation_space_used_at_start_of_incremental_; |
| intptr_t delay = marking_speed_ * MB; |
| intptr_t scavenge_slack = heap_->MaxSemiSpaceSize(); |
| |
| // We try to scan at at least twice the speed that we are allocating. |
| if (promoted_during_marking > bytes_scanned_ / 2 + scavenge_slack + delay) { |
| if (FLAG_trace_gc) { |
| PrintPID("Speed up marking because marker was not keeping up\n"); |
| } |
| speed_up = true; |
| } |
| |
| if (speed_up) { |
| if (state_ != MARKING) { |
| if (FLAG_trace_gc) { |
| PrintPID("Postponing speeding up marking until marking starts\n"); |
| } |
| } else { |
| marking_speed_ += kMarkingSpeedAccelleration; |
| marking_speed_ = static_cast<int>( |
| Min(kMaxMarkingSpeed, |
| static_cast<intptr_t>(marking_speed_ * 1.3))); |
| if (FLAG_trace_gc) { |
| PrintPID("Marking speed increased to %d\n", marking_speed_); |
| } |
| } |
| } |
| |
| if (FLAG_trace_incremental_marking || FLAG_trace_gc || |
| FLAG_print_cumulative_gc_stat) { |
| double end = OS::TimeCurrentMillis(); |
| double delta = (end - start); |
| longest_step_ = Max(longest_step_, delta); |
| steps_took_ += delta; |
| steps_took_since_last_gc_ += delta; |
| heap_->AddMarkingTime(delta); |
| } |
| } |
| |
| |
| void IncrementalMarking::ResetStepCounters() { |
| steps_count_ = 0; |
| steps_took_ = 0; |
| longest_step_ = 0.0; |
| old_generation_space_available_at_start_of_incremental_ = |
| SpaceLeftInOldSpace(); |
| old_generation_space_used_at_start_of_incremental_ = |
| heap_->PromotedTotalSize(); |
| steps_count_since_last_gc_ = 0; |
| steps_took_since_last_gc_ = 0; |
| bytes_rescanned_ = 0; |
| marking_speed_ = kInitialMarkingSpeed; |
| bytes_scanned_ = 0; |
| write_barriers_invoked_since_last_step_ = 0; |
| } |
| |
| |
| int64_t IncrementalMarking::SpaceLeftInOldSpace() { |
| return heap_->MaxOldGenerationSize() - heap_->PromotedSpaceSizeOfObjects(); |
| } |
| |
| } } // namespace v8::internal |
