Get rid of distinction between below- and above-watermark in page allocation....

src/incremental-marking.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 69 matching lines @@
 
     HeapObject* object = HeapObject::cast(*p);
     if (IncrementalMarking::IsWhite(object)) {
       IncrementalMarking::WhiteToGrey(object);
     }
   }
 };
 
 
 static void ClearMarkbits(PagedSpace* space) {
-  PageIterator it(space, PageIterator::PAGES_IN_USE);
+  PageIterator it(space);
 
   while (it.has_next()) {
     Page* p = it.next();
     p->markbits()->Clear();
   }
 }
 
 
 static void ClearMarkbits() {
-  // We are sweeping code and map spaces precisely so clearing is not required.
+  // TODO: Clear the mark bits in the sweeper.
   ClearMarkbits(Heap::old_pointer_space());
   ClearMarkbits(Heap::old_data_space());
   ClearMarkbits(Heap::cell_space());
+  ClearMarkbits(Heap::map_space());
+  ClearMarkbits(Heap::code_space());
 }
 
 
 #ifdef DEBUG
   static void VerifyMarkbitsAreClean(PagedSpace* space) {
-    PageIterator it(space, PageIterator::PAGES_IN_USE);
+    PageIterator it(space);
 
     while (it.has_next()) {
       Page* p = it.next();
       ASSERT(p->markbits()->IsClean());
     }
   }
 
   static void VerifyMarkbitsAreClean() {
     VerifyMarkbitsAreClean(Heap::old_pointer_space());
     VerifyMarkbitsAreClean(Heap::old_data_space());
@@ skipping 159 matching lines @@
                static_cast<int>(end - start));
       }
       allocated = 0;
       if (marking_stack_.is_empty()) MarkingComplete();
     }
   }
 }
 
 
 } }  // namespace v8::internal