--- old/src/hotspot/share/gc/shared/collectedHeap.hpp	2018-04-23 13:45:36.668627360 +0200
+++ new/src/hotspot/share/gc/shared/collectedHeap.hpp	2018-04-23 13:45:36.340614421 +0200
@@ -126,7 +126,13 @@
   CollectedHeap();
 
   // Create a new tlab. All TLAB allocations must go through this.
-  virtual HeapWord* allocate_new_tlab(size_t size);
+  // To allow more flexible TLAB allocations min_word_size specifies
+  // the minimum size needed, while desired_word_size is the requested
+  // size based on ergonomics. The actually allocated size will be
+  // filled out in actual_word_size.
+  virtual HeapWord* allocate_new_tlab(size_t min_word_size,
+                                      size_t desired_word_size,
+                                      size_t* actual_word_size);
 
   // Accumulate statistics on all tlabs.
   virtual void accumulate_statistics_all_tlabs();