A very small marking bitmap (2 bits) is sufficient for large object page since just one object in i…

src/spaces.h

Index: src/spaces.h
===================================================================
--- src/spaces.h	(revision 11322)
+++ src/spaces.h	(working copy)
@@ -183,9 +183,7 @@
     return (length + kBitsPerCell - 1) >> kBitsPerCellLog2;
   }
 
-  int CellsCount() {
-    return CellsForLength(kLength);
-  }
+  INLINE(int CellsCount());
 
   static int SizeFor(int cells_count) {
     return sizeof(MarkBit::CellType) * cells_count;
@@ -501,6 +499,12 @@
   static const int kObjectStartOffset = kBodyOffset - 1 +
       (kObjectStartAlignment - (kBodyOffset - 1) % kObjectStartAlignment);
 
+  static const int kLargeObjectBodyOffset =
+      CODE_POINTER_ALIGN(MAP_POINTER_ALIGN(kHeaderSize + kPointerSize));
+  static const int kLargeObjectStartOffset =
+      kObjectStartAlignment + (kLargeObjectBodyOffset - 1) -
+      (kLargeObjectBodyOffset - 1) % kObjectStartAlignment;
+
   size_t size() const { return size_; }
 
   void set_size(size_t size) {