--- old/src/share/vm/gc/shared/plab.hpp	2015-08-17 17:07:18.687880463 +0200
+++ new/src/share/vm/gc/shared/plab.hpp	2015-08-17 17:07:18.607878068 +0200
@@ -74,7 +74,7 @@
   PLAB(size_t word_sz);
   virtual ~PLAB() {}
 
-  static size_t alignment_reserve() { return AlignmentReserve; }
+  static size_t size_required_for_allocation(size_t word_size) { return word_size + AlignmentReserve; }
 
   // Minimum PLAB size.
   static size_t min_size();
@@ -109,13 +109,6 @@
   size_t waste() { return _wasted; }
   size_t undo_waste() { return _undo_wasted; }
 
-  // Should only be done if we are about to reset with a new buffer of the
-  // given size.
-  void set_word_size(size_t new_word_sz) {
-    assert(new_word_sz > AlignmentReserve, "Too small");
-    _word_sz = new_word_sz;
-  }
-
   // The number of words of unallocated space remaining in the buffer.
   size_t words_remaining() {
     assert(_end >= _top, "Negative buffer");
@@ -127,7 +120,10 @@
   }
 
   // Sets the space of the buffer to be [buf, space+word_sz()).
-  virtual void set_buf(HeapWord* buf) {
+  virtual void set_buf(HeapWord* buf, size_t new_word_sz) {
+    assert(new_word_sz > AlignmentReserve, "Too small");
+    _word_sz = new_word_sz;
+
     _bottom   = buf;
     _top      = _bottom;
     _hard_end = _bottom + word_sz();