When adjusting page's live bytes counter from the mutator adjust owners unswept free bytes counter.

src/mark-compact.cc

 // 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
@@ skipping 1623 matching lines @@
 
 
 void MarkCompactCollector::MarkMapContents(Map* map) {
   // Mark prototype transitions array but don't push it into marking stack.
   // This will make references from it weak. We will clean dead prototype
   // transitions in ClearNonLiveTransitions.
   FixedArray* prototype_transitions = map->prototype_transitions();
   MarkBit mark = Marking::MarkBitFrom(prototype_transitions);
   if (!mark.Get()) {
     mark.Set();
-    MemoryChunk::IncrementLiveBytes(prototype_transitions->address(),
-                                    prototype_transitions->Size());
+    MemoryChunk::IncrementLiveBytesFromGC(prototype_transitions->address(),
+                                          prototype_transitions->Size());
   }
 
   Object** raw_descriptor_array_slot =
       HeapObject::RawField(map, Map::kInstanceDescriptorsOrBitField3Offset);
   Object* raw_descriptor_array = *raw_descriptor_array_slot;
   if (!raw_descriptor_array->IsSmi()) {
     MarkDescriptorArray(
         reinterpret_cast<DescriptorArray*>(raw_descriptor_array));
   }
 
@@ skipping 93 matching lines @@
   // so that we don't waste effort pointlessly scanning for objects.
   ASSERT(!marking_deque->IsFull());
 
   Map* filler_map = heap->one_pointer_filler_map();
   for (HeapObject* object = it->Next();
        object != NULL;
        object = it->Next()) {
     MarkBit markbit = Marking::MarkBitFrom(object);
     if ((object->map() != filler_map) && Marking::IsGrey(markbit)) {
       Marking::GreyToBlack(markbit);
-      MemoryChunk::IncrementLiveBytes(object->address(), object->Size());
+      MemoryChunk::IncrementLiveBytesFromGC(object->address(), object->Size());
       marking_deque->PushBlack(object);
       if (marking_deque->IsFull()) return;
     }
   }
 }
 
 
 static inline int MarkWordToObjectStarts(uint32_t mark_bits, int* starts);
 
 
@@ skipping 31 matching lines @@
     int offset = 0;
     while (grey_objects != 0) {
       int trailing_zeros = CompilerIntrinsics::CountTrailingZeros(grey_objects);
       grey_objects >>= trailing_zeros;
       offset += trailing_zeros;
       MarkBit markbit(&cells[cell_index], 1 << offset, false);
       ASSERT(Marking::IsGrey(markbit));
       Marking::GreyToBlack(markbit);
       Address addr = cell_base + offset * kPointerSize;
       HeapObject* object = HeapObject::FromAddress(addr);
-      MemoryChunk::IncrementLiveBytes(object->address(), object->Size());
+      MemoryChunk::IncrementLiveBytesFromGC(object->address(), object->Size());
       marking_deque->PushBlack(object);
       if (marking_deque->IsFull()) return;
       offset += 2;
       grey_objects >>= 2;
     }
 
     grey_objects >>= (Bitmap::kBitsPerCell - 1);
   }
 }
 
@@ skipping 2085 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal