Let store buffer start out small for a 1Mbyte saving in boot

src/store-buffer.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 67 matching lines @@
 
   // Iterates over all pointers that go from old space to new space.  It will
   // delete the store buffer as it starts so the callback should reenter
   // surviving old-to-new pointers into the store buffer to rebuild it.
   void IteratePointersToNewSpace(ObjectSlotCallback callback);
 
   static const int kStoreBufferOverflowBit = 1 << (14 + kPointerSizeLog2);
   static const int kStoreBufferSize = kStoreBufferOverflowBit;
   static const int kStoreBufferLength = kStoreBufferSize / sizeof(Address);
   static const int kOldStoreBufferLength = kStoreBufferLength * 16;
+  static const int kInitialOldStoreBufferLength = kOldStoreBufferLength >> 9;
   static const int kHashMapLengthLog2 = 12;
   static const int kHashMapLength = 1 << kHashMapLengthLog2;
 
   void Compact();
 
   void GCPrologue();
   void GCEpilogue();
 
   Object*** Limit() { return reinterpret_cast<Object***>(old_limit_); }
   Object*** Start() { return reinterpret_cast<Object***>(old_start_); }
   Object*** Top() { return reinterpret_cast<Object***>(old_top_); }
   void SetTop(Object*** top) {
     ASSERT(top >= Start());
     ASSERT(top <= Limit());
     old_top_ = reinterpret_cast<Address*>(top);
   }
 
   bool old_buffer_is_sorted() { return old_buffer_is_sorted_; }
   bool old_buffer_is_filtered() { return old_buffer_is_filtered_; }
 
   // Goes through the store buffer removing pointers to things that have
   // been promoted.  Rebuilds the store buffer completely if it overflowed.
   void SortUniq();
 
-  void HandleFullness();
+  void EnsureSpace(intptr_t space_needed);
   void Verify();
 
   bool PrepareForIteration();
 
 #ifdef DEBUG
   void Clean();
   // Slow, for asserts only.
   bool CellIsInStoreBuffer(Address cell);
 #endif
 
   void Filter(int flag);
 
  private:
   Heap* heap_;
 
   // The store buffer is divided up into a new buffer that is constantly being
   // filled by mutator activity and an old buffer that is filled with the data
   // from the new buffer after compression.
   Address* start_;
   Address* limit_;
 
   Address* old_start_;
   Address* old_limit_;
   Address* old_top_;
+  Address* old_reserved_limit_;
+  VirtualMemory* old_virtual_memory_;
 
   bool old_buffer_is_sorted_;
   bool old_buffer_is_filtered_;
   bool during_gc_;
   // The garbage collector iterates over many pointers to new space that are not
   // handled by the store buffer.  This flag indicates whether the pointers
   // found by the callbacks should be added to the store buffer or not.
   bool store_buffer_rebuilding_enabled_;
   StoreBufferCallback callback_;
   bool may_move_store_buffer_entries_;
@@ skipping 92 matching lines @@
   }
 
  private:
   StoreBuffer* store_buffer_;
   bool stored_state_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_STORE_BUFFER_H_