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

src/objects.cc

 // 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
@@ skipping 975 matching lines @@
                         :  heap->short_external_string_map()));
   }
   ExternalTwoByteString* self = ExternalTwoByteString::cast(this);
   self->set_resource(resource);
   if (is_symbol) self->Hash();  // Force regeneration of the hash value.
 
   // Fill the remainder of the string with dead wood.
   int new_size = this->Size();  // Byte size of the external String object.
   heap->CreateFillerObjectAt(this->address() + new_size, size - new_size);
   if (Marking::IsBlack(Marking::MarkBitFrom(this))) {
-    MemoryChunk::IncrementLiveBytes(this->address(), new_size - size);
+    MemoryChunk::IncrementLiveBytesFromMutator(this->address(), new_size - size);
   }
   return true;
 }
 
 
 bool String::MakeExternal(v8::String::ExternalAsciiStringResource* resource) {
 #ifdef DEBUG
   if (FLAG_enable_slow_asserts) {
     // Assert that the resource and the string are equivalent.
     ASSERT(static_cast<size_t>(this->length()) == resource->length());
@@ skipping 23 matching lines @@
                   : heap->short_external_ascii_string_map());
   }
   ExternalAsciiString* self = ExternalAsciiString::cast(this);
   self->set_resource(resource);
   if (is_symbol) self->Hash();  // Force regeneration of the hash value.
 
   // Fill the remainder of the string with dead wood.
   int new_size = this->Size();  // Byte size of the external String object.
   heap->CreateFillerObjectAt(this->address() + new_size, size - new_size);
   if (Marking::IsBlack(Marking::MarkBitFrom(this))) {
-    MemoryChunk::IncrementLiveBytes(this->address(), new_size - size);
+    MemoryChunk::IncrementLiveBytesFromMutator(this->address(), new_size - size);
   }
   return true;
 }
 
 
 void String::StringShortPrint(StringStream* accumulator) {
   int len = length();
   if (len > kMaxShortPrintLength) {
     accumulator->Add("<Very long string[%u]>", len);
     return;
@@ skipping 2402 matching lines @@
   // We have now successfully allocated all the necessary objects.
   // Changes can now be made with the guarantee that all of them take effect.
 
   // Resize the object in the heap if necessary.
   int new_instance_size = new_map->instance_size();
   int instance_size_delta = map_of_this->instance_size() - new_instance_size;
   ASSERT(instance_size_delta >= 0);
   current_heap->CreateFillerObjectAt(this->address() + new_instance_size,
                                      instance_size_delta);
   if (Marking::IsBlack(Marking::MarkBitFrom(this))) {
-    MemoryChunk::IncrementLiveBytes(this->address(), -instance_size_delta);
+    MemoryChunk::IncrementLiveBytesFromMutator(this->address(),
+                                               -instance_size_delta);
   }
 
 
   set_map(new_map);
   new_map->clear_instance_descriptors();
 
   set_properties(dictionary);
 
   current_heap->isolate()->counters()->props_to_dictionary()->Increment();
 
@@ skipping 9332 matching lines @@
   if (break_point_objects()->IsUndefined()) return 0;
   // Single break point.
   if (!break_point_objects()->IsFixedArray()) return 1;
   // Multiple break points.
   return FixedArray::cast(break_point_objects())->length();
 }
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 
 } }  // namespace v8::internal