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Diffstat (limited to 'deps/v8/src/incremental-marking.cc')
| -rw-r--r-- | deps/v8/src/incremental-marking.cc | 926 |
1 files changed, 926 insertions, 0 deletions
diff --git a/deps/v8/src/incremental-marking.cc b/deps/v8/src/incremental-marking.cc new file mode 100644 index 0000000000..d0346171d3 --- /dev/null +++ b/deps/v8/src/incremental-marking.cc @@ -0,0 +1,926 @@ +// Copyright 2011 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 "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), + allocation_marking_factor_(0), + allocated_(0), + no_marking_scope_depth_(0) { +} + + +void IncrementalMarking::TearDown() { + delete marking_deque_memory_; +} + + +void IncrementalMarking::RecordWriteSlow(HeapObject* obj, + Object** slot, + Object* value) { + if (BaseRecordWrite(obj, slot, value) && is_compacting_ && 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* value, + Isolate* isolate) { + ASSERT(obj->IsHeapObject()); + + // Fast cases should already be covered by RecordWriteStub. + ASSERT(value->IsHeapObject()); + ASSERT(!value->IsHeapNumber()); + ASSERT(!value->IsString() || + value->IsConsString() || + value->IsSlicedString()); + ASSERT(Marking::IsWhite(Marking::MarkBitFrom(HeapObject::cast(value)))); + + IncrementalMarking* marking = isolate->heap()->incremental_marking(); + ASSERT(!marking->is_compacting_); + marking->RecordWrite(obj, NULL, value); +} + + +void IncrementalMarking::RecordWriteForEvacuationFromCode(HeapObject* obj, + Object** slot, + Isolate* isolate) { + IncrementalMarking* marking = isolate->heap()->incremental_marking(); + ASSERT(marking->is_compacting_); + 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) && is_compacting_) { + 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)); + } + } +} + + +class IncrementalMarkingMarkingVisitor : public ObjectVisitor { + public: + IncrementalMarkingMarkingVisitor(Heap* heap, + IncrementalMarking* incremental_marking) + : heap_(heap), + incremental_marking_(incremental_marking) { + } + + void VisitEmbeddedPointer(RelocInfo* rinfo) { + ASSERT(rinfo->rmode() == RelocInfo::EMBEDDED_OBJECT); + Object* target = rinfo->target_object(); + if (target->NonFailureIsHeapObject()) { + heap_->mark_compact_collector()->RecordRelocSlot(rinfo, target); + MarkObject(target); + } + } + + void VisitCodeTarget(RelocInfo* rinfo) { + ASSERT(RelocInfo::IsCodeTarget(rinfo->rmode())); + Object* target = Code::GetCodeFromTargetAddress(rinfo->target_address()); + heap_->mark_compact_collector()->RecordRelocSlot(rinfo, Code::cast(target)); + MarkObject(target); + } + + void VisitDebugTarget(RelocInfo* rinfo) { + ASSERT((RelocInfo::IsJSReturn(rinfo->rmode()) && + rinfo->IsPatchedReturnSequence()) || + (RelocInfo::IsDebugBreakSlot(rinfo->rmode()) && + rinfo->IsPatchedDebugBreakSlotSequence())); + Object* target = Code::GetCodeFromTargetAddress(rinfo->call_address()); + heap_->mark_compact_collector()->RecordRelocSlot(rinfo, Code::cast(target)); + MarkObject(target); + } + + void VisitCodeEntry(Address entry_address) { + Object* target = Code::GetObjectFromEntryAddress(entry_address); + heap_->mark_compact_collector()-> + RecordCodeEntrySlot(entry_address, Code::cast(target)); + MarkObject(target); + } + + void VisitPointer(Object** p) { + Object* obj = *p; + if (obj->NonFailureIsHeapObject()) { + heap_->mark_compact_collector()->RecordSlot(p, p, obj); + MarkObject(obj); + } + } + + void VisitPointers(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(obj); + } + } + } + + private: + // Mark object pointed to by p. + INLINE(void MarkObject(Object* obj)) { + HeapObject* heap_object = HeapObject::cast(obj); + MarkBit mark_bit = Marking::MarkBitFrom(heap_object); + if (mark_bit.data_only()) { + if (incremental_marking_->MarkBlackOrKeepGrey(mark_bit)) { + MemoryChunk::IncrementLiveBytesFromGC(heap_object->address(), + heap_object->Size()); + } + } else if (Marking::IsWhite(mark_bit)) { + incremental_marking_->WhiteToGreyAndPush(heap_object, mark_bit); + } + } + + Heap* heap_; + IncrementalMarking* incremental_marking_; +}; + + +class IncrementalMarkingRootMarkingVisitor : public ObjectVisitor { + public: + IncrementalMarkingRootMarkingVisitor(Heap* heap, + IncrementalMarking* incremental_marking) + : heap_(heap), + 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()) { + if (incremental_marking_->MarkBlackOrKeepGrey(mark_bit)) { + MemoryChunk::IncrementLiveBytesFromGC(heap_object->address(), + heap_object->Size()); + } + } else { + if (Marking::IsWhite(mark_bit)) { + incremental_marking_->WhiteToGreyAndPush(heap_object, mark_bit); + } + } + } + + Heap* heap_; + IncrementalMarking* incremental_marking_; +}; + + +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->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_->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_->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 + + return !FLAG_expose_gc && + FLAG_incremental_marking && + !Serializer::enabled() && + heap_->PromotedSpaceSize() > 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() { + if (FLAG_trace_incremental_marking) { + PrintF("[IncrementalMarking] Start\n"); + } + ASSERT(FLAG_incremental_marking); + ASSERT(state_ == STOPPED); + + ResetStepCounters(); + + if (heap_->old_pointer_space()->IsSweepingComplete() && + heap_->old_data_space()->IsSweepingComplete()) { + StartMarking(ALLOW_COMPACTION); + } else { + if (FLAG_trace_incremental_marking) { + PrintF("[IncrementalMarking] Start sweeping.\n"); + } + state_ = SWEEPING; + } + + heap_->new_space()->LowerInlineAllocationLimit(kAllocatedThreshold); +} + + +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); + } +} + + +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(); + +#ifdef DEBUG + // Marking bits are cleared by the sweeper. + 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(heap_, this); + heap_->IterateStrongRoots(&visitor, VISIT_ONLY_STRONG); + + // 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); + ASSERT(Marking::IsGrey(mark_bit) || + (obj->IsFiller() && Marking::IsWhite(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::VisitGlobalContext(Context* ctx, ObjectVisitor* v) { + v->VisitPointers( + HeapObject::RawField( + ctx, Context::MarkCompactBodyDescriptor::kStartOffset), + HeapObject::RawField( + ctx, Context::MarkCompactBodyDescriptor::kEndOffset)); + + MarkCompactCollector* collector = heap_->mark_compact_collector(); + for (int idx = Context::FIRST_WEAK_SLOT; + idx < Context::GLOBAL_CONTEXT_SLOTS; + ++idx) { + Object** slot = + HeapObject::RawField(ctx, FixedArray::OffsetOfElementAt(idx)); + collector->RecordSlot(slot, slot, *slot); + } +} + + +void IncrementalMarking::Hurry() { + if (state() == MARKING) { + double start = 0.0; + if (FLAG_trace_incremental_marking) { + PrintF("[IncrementalMarking] Hurry\n"); + start = OS::TimeCurrentMillis(); + } + // TODO(gc) hurry can mark objects it encounters black as mutator + // was stopped. + Map* filler_map = heap_->one_pointer_filler_map(); + Map* global_context_map = heap_->global_context_map(); + IncrementalMarkingMarkingVisitor marking_visitor(heap_, this); + 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; + } else if (map == global_context_map) { + // Global contexts have weak fields. + VisitGlobalContext(Context::cast(obj), &marking_visitor); + } else { + obj->Iterate(&marking_visitor); + } + + MarkBit mark_bit = Marking::MarkBitFrom(obj); + ASSERT(!Marking::IsBlack(mark_bit)); + Marking::MarkBlack(mark_bit); + MemoryChunk::IncrementLiveBytesFromGC(obj->address(), obj->Size()); + } + state_ = COMPLETE; + if (FLAG_trace_incremental_marking) { + double end = OS::TimeCurrentMillis(); + PrintF("[IncrementalMarking] Complete (hurry), spent %d ms.\n", + static_cast<int>(end - start)); + } + } + + 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_->global_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() { + 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 (!heap_->idle_notification_will_schedule_next_gc()) { + heap_->isolate()->stack_guard()->RequestGC(); + } +} + + +void IncrementalMarking::Step(intptr_t allocated_bytes) { + 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) return; + + if (state_ == MARKING && no_marking_scope_depth_ > 0) return; + + intptr_t bytes_to_process = allocated_ * allocation_marking_factor_; + bytes_scanned_ += bytes_to_process; + + double start = 0; + + if (FLAG_trace_incremental_marking || FLAG_trace_gc) { + start = OS::TimeCurrentMillis(); + } + + if (state_ == SWEEPING) { + if (heap_->AdvanceSweepers(static_cast<int>(bytes_to_process))) { + bytes_scanned_ = 0; + StartMarking(PREVENT_COMPACTION); + } + } else if (state_ == MARKING) { + Map* filler_map = heap_->one_pointer_filler_map(); + Map* global_context_map = heap_->global_context_map(); + IncrementalMarkingMarkingVisitor marking_visitor(heap_, this); + 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); + bytes_to_process -= size; + MarkBit map_mark_bit = Marking::MarkBitFrom(map); + if (Marking::IsWhite(map_mark_bit)) { + WhiteToGreyAndPush(map, map_mark_bit); + } + + // TODO(gc) switch to static visitor instead of normal visitor. + if (map == global_context_map) { + // Global contexts have weak fields. + Context* ctx = Context::cast(obj); + + // We will mark cache black with a separate pass + // when we finish marking. + MarkObjectGreyDoNotEnqueue(ctx->normalized_map_cache()); + + VisitGlobalContext(ctx, &marking_visitor); + } else { + obj->IterateBody(map->instance_type(), size, &marking_visitor); + } + + MarkBit obj_mark_bit = Marking::MarkBitFrom(obj); + SLOW_ASSERT(Marking::IsGrey(obj_mark_bit) || + (obj->IsFiller() && Marking::IsWhite(obj_mark_bit))); + Marking::MarkBlack(obj_mark_bit); + MemoryChunk::IncrementLiveBytesFromGC(obj->address(), size); + } + if (marking_deque_.IsEmpty()) MarkingComplete(); + } + + allocated_ = 0; + + steps_count_++; + steps_count_since_last_gc_++; + + bool speed_up = false; + + if ((steps_count_ % kAllocationMarkingFactorSpeedupInterval) == 0) { + if (FLAG_trace_gc) { + PrintF("Speed up marking after %d steps\n", + static_cast<int>(kAllocationMarkingFactorSpeedupInterval)); + } + 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() * (allocation_marking_factor_ + 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) PrintF("Speed up marking because of low space left\n"); + speed_up = true; + } + + bool size_of_old_space_multiplied_by_n_during_marking = + (heap_->PromotedTotalSize() > + (allocation_marking_factor_ + 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) { + PrintF("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 = allocation_marking_factor_ * 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) { + PrintF("Speed up marking because marker was not keeping up\n"); + } + speed_up = true; + } + + if (speed_up) { + if (state_ != MARKING) { + if (FLAG_trace_gc) { + PrintF("Postponing speeding up marking until marking starts\n"); + } + } else { + allocation_marking_factor_ += kAllocationMarkingFactorSpeedup; + allocation_marking_factor_ = static_cast<int>( + Min(kMaxAllocationMarkingFactor, + static_cast<intptr_t>(allocation_marking_factor_ * 1.3))); + if (FLAG_trace_gc) { + PrintF("Marking speed increased to %d\n", allocation_marking_factor_); + } + } + } + + if (FLAG_trace_incremental_marking || FLAG_trace_gc) { + double end = OS::TimeCurrentMillis(); + double delta = (end - start); + longest_step_ = Max(longest_step_, delta); + steps_took_ += delta; + steps_took_since_last_gc_ += 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; + allocation_marking_factor_ = kInitialAllocationMarkingFactor; + bytes_scanned_ = 0; +} + + +int64_t IncrementalMarking::SpaceLeftInOldSpace() { + return heap_->MaxOldGenerationSize() - heap_->PromotedSpaceSize(); +} + +} } // namespace v8::internal |