--- old/src/share/vm/gc_implementation/shared/vmGCOperations.cpp	2015-02-05 16:34:49.885948157 +0100
+++ new/src/share/vm/gc_implementation/shared/vmGCOperations.cpp	2015-02-05 16:34:49.797951023 +0100
@@ -179,10 +179,10 @@
 
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   GCCauseSetter gccs(gch, _gc_cause);
-  _res = gch->satisfy_failed_allocation(_size, _tlab);
-  assert(gch->is_in_reserved_or_null(_res), "result not in heap");
+  _result = gch->satisfy_failed_allocation(_word_size, _tlab);
+  assert(gch->is_in_reserved_or_null(_result), "result not in heap");
 
-  if (_res == NULL && GC_locker::is_active_and_needs_gc()) {
+  if (_result == NULL && GC_locker::is_active_and_needs_gc()) {
     set_gc_locked();
   }
 }
@@ -299,3 +299,9 @@
     set_gc_locked();
   }
 }
+
+VM_CollectForAllocation::VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause) :
+    VM_GC_Operation(gc_count_before, cause), _result(NULL), _word_size(word_size) {
+  // G1's incremental collections are not always caused by an allocation, which is indicated by word_size = 0.
+  assert(_word_size != 0 || UseG1GC, "word_size = 0 should only happen with G1");
+}