As a last resort try to allocate out of the smaller size size-class in

src/spaces.h

 // 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 1436 matching lines @@
     delete mutex_;
   }
 
   intptr_t Concatenate(FreeListCategory* category);
 
   void Reset();
 
   void Free(FreeListNode* node, int size_in_bytes);
 
   FreeListNode* PickNodeFromList(int *node_size);
+  FreeListNode* PickNodeFromList(int size_in_bytes, int *node_size);
 
   intptr_t EvictFreeListItemsInList(Page* p);
 
   void RepairFreeList(Heap* heap);
 
   FreeListNode** GetTopAddress() { return &top_; }
   FreeListNode* top() const { return top_; }
   void set_top(FreeListNode* top) { top_ = top; }
 
   FreeListNode** GetEndAddress() { return &end_; }
@@ skipping 346 matching lines @@
   bool CanExpand();
 
   // Returns the number of total pages in this space.
   int CountTotalPages();
 
   // Return size of allocatable area on a page in this space.
   inline int AreaSize() {
     return area_size_;
   }
 
-  bool ConstantAllocationSize() {
-    return identity() == MAP_SPACE || identity() == CELL_SPACE ||
-        identity() == PROPERTY_CELL_SPACE;
-  }
-
  protected:
   FreeList* free_list() { return &free_list_; }
 
   int area_size_;
 
   // Maximum capacity of this space.
   intptr_t max_capacity_;
 
   intptr_t SizeOfFirstPage();
 
@@ skipping 1039 matching lines @@
   }
   // Must be small, since an iteration is used for lookup.
   static const int kMaxComments = 64;
 };
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_SPACES_H_