1 files changed, 169 insertions, 224 deletions

diff --git a/src/3rdparty/v8/src/incremental-marking.cc b/src/3rdparty/v8/src/incremental-marking.cc
index 94afffa..b34d6d9 100644
--- a/src/3rdparty/v8/src/incremental-marking.cc
+++ b/src/3rdparty/v8/src/incremental-marking.cc
@@ -31,6 +31,8 @@
 
 #include "code-stubs.h"
 #include "compilation-cache.h"
+#include "objects-visiting.h"
+#include "objects-visiting-inl.h"
 #include "v8conversions.h"
 
 namespace v8 {
@@ -42,7 +44,6 @@ IncrementalMarking::IncrementalMarking(Heap* heap)
       state_(STOPPED),
       marking_deque_memory_(NULL),
       marking_deque_memory_committed_(false),
-      marker_(this, heap->mark_compact_collector()),
       steps_count_(0),
       steps_took_(0),
       longest_step_(0.0),
@@ -51,7 +52,7 @@ IncrementalMarking::IncrementalMarking(Heap* heap)
       steps_count_since_last_gc_(0),
       steps_took_since_last_gc_(0),
       should_hurry_(false),
-      allocation_marking_factor_(0),
+      marking_speed_(0),
       allocated_(0),
       no_marking_scope_depth_(0) {
 }
@@ -65,7 +66,7 @@ void IncrementalMarking::TearDown() {
 void IncrementalMarking::RecordWriteSlow(HeapObject* obj,
                                          Object** slot,
                                          Object* value) {
-  if (BaseRecordWrite(obj, slot, value) && is_compacting_ && slot != NULL) {
+  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.
@@ -80,17 +81,19 @@ 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_);
+
+  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, NULL, value);
 }
 
@@ -98,8 +101,20 @@ void IncrementalMarking::RecordWriteFromCode(HeapObject* obj,
 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);
 }
 
@@ -125,9 +140,9 @@ void IncrementalMarking::RecordCodeTargetPatch(Address pc, HeapObject* value) {
 
 
 void IncrementalMarking::RecordWriteOfCodeEntrySlow(JSFunction* host,
-                                                Object** slot,
-                                                Code* value) {
-  if (BaseRecordWrite(host, slot, value) && is_compacting_) {
+                                                    Object** slot,
+                                                    Code* value) {
+  if (BaseRecordWrite(host, slot, value)) {
     ASSERT(slot != NULL);
     heap_->mark_compact_collector()->
         RecordCodeEntrySlot(reinterpret_cast<Address>(slot), value);
@@ -160,93 +175,92 @@ void IncrementalMarking::RecordWriteIntoCodeSlow(HeapObject* obj,
 }
 
 
-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);
+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 VisitCodeTarget(RelocInfo* rinfo) {
-    ASSERT(RelocInfo::IsCodeTarget(rinfo->rmode()));
-    Code* target = Code::GetCodeFromTargetAddress(rinfo->target_address());
-    if (FLAG_cleanup_code_caches_at_gc && target->is_inline_cache_stub()
-        && (target->ic_age() != heap_->global_ic_age())) {
-      IC::Clear(rinfo->pc());
-      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);
+class IncrementalMarkingMarkingVisitor
+    : public StaticMarkingVisitor<IncrementalMarkingMarkingVisitor> {
+ public:
+  static void Initialize() {
+    StaticMarkingVisitor<IncrementalMarkingMarkingVisitor>::Initialize();
+
+    table_.Register(kVisitNativeContext, &VisitNativeContextIncremental);
+    table_.Register(kVisitJSRegExp, &VisitJSRegExp);
   }
 
-  void VisitCodeEntry(Address entry_address) {
-    Object* target = Code::GetObjectFromEntryAddress(entry_address);
-    heap_->mark_compact_collector()->
-        RecordCodeEntrySlot(entry_address, Code::cast(target));
-    MarkObject(target);
+  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);
   }
 
-  void VisitSharedFunctionInfo(SharedFunctionInfo* shared) {
-    if (shared->ic_age() != heap_->global_ic_age()) {
-      shared->ResetForNewContext(heap_->global_ic_age());
-    }
+  static void VisitJSWeakMap(Map* map, HeapObject* object) {
+    Heap* heap = map->GetHeap();
+    VisitPointers(heap,
+                  HeapObject::RawField(object, JSWeakMap::kPropertiesOffset),
+                  HeapObject::RawField(object, JSWeakMap::kSize));
   }
 
-  void VisitPointer(Object** p) {
+  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(obj);
+      heap->mark_compact_collector()->RecordSlot(p, p, obj);
+      MarkObject(heap, obj);
     }
   }
 
-  void VisitPointers(Object** start, Object** end) {
+  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(obj);
+        heap->mark_compact_collector()->RecordSlot(start, p, obj);
+        MarkObject(heap, obj);
       }
     }
   }
 
- private:
-  // Mark object pointed to by p.
-  INLINE(void MarkObject(Object* 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()) {
-      if (incremental_marking_->MarkBlackOrKeepGrey(mark_bit)) {
+      if (heap->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->incremental_marking()->WhiteToGreyAndPush(heap_object, mark_bit);
     }
   }
 
-  Heap* heap_;
-  IncrementalMarking* incremental_marking_;
+  // 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;
+  }
 };
 
 
@@ -290,6 +304,11 @@ class IncrementalMarkingRootMarkingVisitor : public ObjectVisitor {
 };
 
 
+void IncrementalMarking::Initialize() {
+  IncrementalMarkingMarkingVisitor::Initialize();
+}
+
+
 void IncrementalMarking::SetOldSpacePageFlags(MemoryChunk* chunk,
                                               bool is_marking,
                                               bool is_compacting) {
@@ -498,19 +517,6 @@ void IncrementalMarking::Start() {
 }
 
 
-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");
@@ -537,8 +543,8 @@ void IncrementalMarking::StartMarking(CompactionFlag flag) {
 
   ActivateIncrementalWriteBarrier();
 
-#ifdef DEBUG
   // Marking bits are cleared by the sweeper.
+#ifdef VERIFY_HEAP
   if (FLAG_verify_heap) {
     heap_->mark_compact_collector()->VerifyMarkbitsAreClean();
   }
@@ -623,20 +629,50 @@ void IncrementalMarking::UpdateMarkingDequeAfterScavenge() {
 }
 
 
-void IncrementalMarking::VisitGlobalContext(Context* ctx, ObjectVisitor* v) {
-  v->VisitPointers(
-      HeapObject::RawField(
-          ctx, Context::MarkCompactBodyDescriptor::kStartOffset),
-      HeapObject::RawField(
-          ctx, Context::MarkCompactBodyDescriptor::kEndOffset));
+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 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);
+}
 
-  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::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);
+    bytes_to_process -= size;
+    VisitObject(map, obj, size);
+  }
+}
+
+
+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));
   }
 }
 
@@ -650,45 +686,7 @@ void IncrementalMarking::Hurry() {
     }
     // 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 if (map->instance_type() == MAP_TYPE) {
-        Map* map = Map::cast(obj);
-        heap_->ClearCacheOnMap(map);
-
-        // When map collection is enabled we have to mark through map's
-        // transitions and back pointers in a special way to make these links
-        // weak.  Only maps for subclasses of JSReceiver can have transitions.
-        STATIC_ASSERT(LAST_TYPE == LAST_JS_RECEIVER_TYPE);
-        if (FLAG_collect_maps &&
-            map->instance_type() >= FIRST_JS_RECEIVER_TYPE) {
-          marker_.MarkMapContents(map);
-        } else {
-          marking_visitor.VisitPointers(
-              HeapObject::RawField(map, Map::kPointerFieldsBeginOffset),
-              HeapObject::RawField(map, Map::kPointerFieldsEndOffset));
-        }
-      } 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());
-    }
+    ProcessMarkingDeque();
     state_ = COMPLETE;
     if (FLAG_trace_incremental_marking) {
       double end = OS::TimeCurrentMillis();
@@ -704,7 +702,7 @@ void IncrementalMarking::Hurry() {
                                           PolymorphicCodeCache::kSize);
   }
 
-  Object* context = heap_->global_contexts_list();
+  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.
@@ -794,11 +792,25 @@ void IncrementalMarking::Step(intptr_t allocated_bytes,
 
   allocated_ += allocated_bytes;
 
-  if (allocated_ < kAllocatedThreshold) return;
+  if (allocated_ < kAllocatedThreshold &&
+      write_barriers_invoked_since_last_step_ <
+          kWriteBarriersInvokedThreshold) {
+    return;
+  }
 
   if (state_ == MARKING && no_marking_scope_depth_ > 0) return;
 
-  intptr_t bytes_to_process = allocated_ * allocation_marking_factor_;
+  // 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_, kWriteBarriersInvokedThreshold);
+  allocated_ = 0;
+  write_barriers_invoked_since_last_step_ = 0;
+
   bytes_scanned_ += bytes_to_process;
 
   double start = 0;
@@ -813,87 +825,19 @@ void IncrementalMarking::Step(intptr_t allocated_bytes,
       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 if (map->instance_type() == MAP_TYPE) {
-        Map* map = Map::cast(obj);
-        heap_->ClearCacheOnMap(map);
-
-        // When map collection is enabled we have to mark through map's
-        // transitions and back pointers in a special way to make these links
-        // weak.  Only maps for subclasses of JSReceiver can have transitions.
-        STATIC_ASSERT(LAST_TYPE == LAST_JS_RECEIVER_TYPE);
-        if (FLAG_collect_maps &&
-            map->instance_type() >= FIRST_JS_RECEIVER_TYPE) {
-          marker_.MarkMapContents(map);
-        } else {
-          marking_visitor.VisitPointers(
-              HeapObject::RawField(map, Map::kPointerFieldsBeginOffset),
-              HeapObject::RawField(map, Map::kPointerFieldsEndOffset));
-        }
-      } else if (map->instance_type() == JS_FUNCTION_TYPE) {
-        marking_visitor.VisitPointers(
-            HeapObject::RawField(obj, JSFunction::kPropertiesOffset),
-            HeapObject::RawField(obj, JSFunction::kCodeEntryOffset));
-
-        marking_visitor.VisitCodeEntry(
-            obj->address() + JSFunction::kCodeEntryOffset);
-
-        marking_visitor.VisitPointers(
-            HeapObject::RawField(obj,
-                                 JSFunction::kCodeEntryOffset + kPointerSize),
-            HeapObject::RawField(obj,
-                                 JSFunction::kNonWeakFieldsEndOffset));
-      } 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);
-    }
+    ProcessMarkingDeque(bytes_to_process);
     if (marking_deque_.IsEmpty()) MarkingComplete(action);
   }
 
-  allocated_ = 0;
-
   steps_count_++;
   steps_count_since_last_gc_++;
 
   bool speed_up = false;
 
-  if ((steps_count_ % kAllocationMarkingFactorSpeedupInterval) == 0) {
+  if ((steps_count_ % kMarkingSpeedAccellerationInterval) == 0) {
     if (FLAG_trace_gc) {
-      PrintF("Speed up marking after %d steps\n",
-             static_cast<int>(kAllocationMarkingFactorSpeedupInterval));
+      PrintPID("Speed up marking after %d steps\n",
+               static_cast<int>(kMarkingSpeedAccellerationInterval));
     }
     speed_up = true;
   }
@@ -902,35 +846,35 @@ void IncrementalMarking::Step(intptr_t allocated_bytes,
       (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) <
+      (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) PrintF("Speed up marking because of low space left\n");
+    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() >
-       (allocation_marking_factor_ + 1) *
+       (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) {
-      PrintF("Speed up marking because of heap size increase\n");
+      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 = allocation_marking_factor_ * MB;
+  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) {
-      PrintF("Speed up marking because marker was not keeping up\n");
+      PrintPID("Speed up marking because marker was not keeping up\n");
     }
     speed_up = true;
   }
@@ -938,15 +882,15 @@ void IncrementalMarking::Step(intptr_t allocated_bytes,
   if (speed_up) {
     if (state_ != MARKING) {
       if (FLAG_trace_gc) {
-        PrintF("Postponing speeding up marking until marking starts\n");
+        PrintPID("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)));
+      marking_speed_ += kMarkingSpeedAccellerationInterval;
+      marking_speed_ = static_cast<int>(
+          Min(kMaxMarkingSpeed,
+              static_cast<intptr_t>(marking_speed_ * 1.3)));
       if (FLAG_trace_gc) {
-        PrintF("Marking speed increased to %d\n", allocation_marking_factor_);
+        PrintPID("Marking speed increased to %d\n", marking_speed_);
       }
     }
   }
@@ -972,8 +916,9 @@ void IncrementalMarking::ResetStepCounters() {
   steps_count_since_last_gc_ = 0;
   steps_took_since_last_gc_ = 0;
   bytes_rescanned_ = 0;
-  allocation_marking_factor_ = kInitialAllocationMarkingFactor;
+  marking_speed_ = kInitialMarkingSpeed;
   bytes_scanned_ = 0;
+  write_barriers_invoked_since_last_step_ = 0;
 }