--- old/src/share/vm/memory/defNewGeneration.cpp	2014-10-17 16:28:41.000000000 +0200
+++ new/src/share/vm/memory/defNewGeneration.cpp	2014-10-17 16:28:41.000000000 +0200
@@ -56,9 +56,7 @@
 
 // Methods of protected closure types.
 
-DefNewGeneration::IsAliveClosure::IsAliveClosure(Generation* g) : _g(g) {
-  assert(g->level() == 0, "Optimized for youngest gen.");
-}
+DefNewGeneration::IsAliveClosure::IsAliveClosure(Generation* g) : _g(g) { }
 bool DefNewGeneration::IsAliveClosure::do_object_b(oop p) {
   return (HeapWord*)p >= _g->reserved().end() || p->is_forwarded();
 }
@@ -83,39 +81,36 @@
 void DefNewGeneration::FastKeepAliveClosure::do_oop(narrowOop* p) { DefNewGeneration::FastKeepAliveClosure::do_oop_work(p); }
 
 DefNewGeneration::EvacuateFollowersClosure::
-EvacuateFollowersClosure(GenCollectedHeap* gch, int level,
+EvacuateFollowersClosure(GenCollectedHeap* gch,
                          ScanClosure* cur, ScanClosure* older) :
-  _gch(gch), _level(level),
-  _scan_cur_or_nonheap(cur), _scan_older(older)
+  _gch(gch), _scan_cur_or_nonheap(cur), _scan_older(older)
 {}
 
 void DefNewGeneration::EvacuateFollowersClosure::do_void() {
   do {
-    _gch->oop_since_save_marks_iterate(_level, _scan_cur_or_nonheap,
+    _gch->oop_since_save_marks_iterate(Generation::Young, _scan_cur_or_nonheap,
                                        _scan_older);
-  } while (!_gch->no_allocs_since_save_marks(_level));
+  } while (!_gch->no_allocs_since_save_marks(Generation::Young));
 }
 
 DefNewGeneration::FastEvacuateFollowersClosure::
-FastEvacuateFollowersClosure(GenCollectedHeap* gch, int level,
+FastEvacuateFollowersClosure(GenCollectedHeap* gch,
                              DefNewGeneration* gen,
                              FastScanClosure* cur, FastScanClosure* older) :
-  _gch(gch), _level(level), _gen(gen),
-  _scan_cur_or_nonheap(cur), _scan_older(older)
+  _gch(gch), _gen(gen), _scan_cur_or_nonheap(cur), _scan_older(older)
 {}
 
 void DefNewGeneration::FastEvacuateFollowersClosure::do_void() {
   do {
-    _gch->oop_since_save_marks_iterate(_level, _scan_cur_or_nonheap,
+    _gch->oop_since_save_marks_iterate(Generation::Young, _scan_cur_or_nonheap,
                                        _scan_older);
-  } while (!_gch->no_allocs_since_save_marks(_level));
+  } while (!_gch->no_allocs_since_save_marks(Generation::Young));
   guarantee(_gen->promo_failure_scan_is_complete(), "Failed to finish scan");
 }
 
 ScanClosure::ScanClosure(DefNewGeneration* g, bool gc_barrier) :
     OopsInKlassOrGenClosure(g), _g(g), _gc_barrier(gc_barrier)
 {
-  assert(_g->level() == 0, "Optimized for youngest generation");
   _boundary = _g->reserved().end();
 }
 
@@ -125,7 +120,6 @@
 FastScanClosure::FastScanClosure(DefNewGeneration* g, bool gc_barrier) :
     OopsInKlassOrGenClosure(g), _g(g), _gc_barrier(gc_barrier)
 {
-  assert(_g->level() == 0, "Optimized for youngest generation");
   _boundary = _g->reserved().end();
 }
 
@@ -166,7 +160,6 @@
 ScanWeakRefClosure::ScanWeakRefClosure(DefNewGeneration* g) :
   _g(g)
 {
-  assert(_g->level() == 0, "Optimized for youngest generation");
   _boundary = _g->reserved().end();
 }
 
@@ -184,9 +177,8 @@
 
 DefNewGeneration::DefNewGeneration(ReservedSpace rs,
                                    size_t initial_size,
-                                   int level,
                                    const char* policy)
-  : Generation(rs, initial_size, level),
+  : Generation(rs, initial_size),
     _promo_failure_drain_in_progress(false),
     _should_allocate_from_space(false)
 {
@@ -230,7 +222,7 @@
 
   compute_space_boundaries(0, SpaceDecorator::Clear, SpaceDecorator::Mangle);
   update_counters();
-  _next_gen = NULL;
+  _old_gen = NULL;
   _tenuring_threshold = MaxTenuringThreshold;
   _pretenure_size_threshold_words = PretenureSizeThreshold >> LogHeapWordSize;
 
@@ -382,13 +374,9 @@
     return;
   }
 
-  int next_level = level() + 1;
   GenCollectedHeap* gch = GenCollectedHeap::heap();
-  assert(next_level < gch->_n_gens,
-         "DefNewGeneration cannot be an oldest gen");
 
-  Generation* next_gen = gch->_gens[next_level];
-  size_t old_size = next_gen->capacity();
+  size_t old_size = gch->old_gen()->capacity();
   size_t new_size_before = _virtual_space.committed_size();
   size_t min_new_size = spec()->init_size();
   size_t max_new_size = reserved().byte_size();
@@ -572,7 +560,7 @@
   DefNewTracer gc_tracer;
   gc_tracer.report_gc_start(gch->gc_cause(), _gc_timer->gc_start());
 
-  _next_gen = gch->next_gen(this);
+  _old_gen = gch->old_gen();
 
   // If the next generation is too full to accommodate promotion
   // from this generation, pass on collection; let the next generation
@@ -605,7 +593,7 @@
 
   gch->rem_set()->prepare_for_younger_refs_iterate(false);
 
-  assert(gch->no_allocs_since_save_marks(0),
+  assert(gch->no_allocs_since_save_marks(Generation::Young),
          "save marks have not been newly set.");
 
   // Not very pretty.
@@ -621,14 +609,14 @@
                                            false);
 
   set_promo_failure_scan_stack_closure(&fsc_with_no_gc_barrier);
-  FastEvacuateFollowersClosure evacuate_followers(gch, _level, this,
+  FastEvacuateFollowersClosure evacuate_followers(gch, this,
                                                   &fsc_with_no_gc_barrier,
                                                   &fsc_with_gc_barrier);
 
-  assert(gch->no_allocs_since_save_marks(0),
+  assert(gch->no_allocs_since_save_marks(Generation::Young),
          "save marks have not been newly set.");
 
-  gch->gen_process_roots(_level,
+  gch->gen_process_roots(Generation::Young,
                          true,  // Process younger gens, if any,
                                 // as strong roots.
                          true,  // activate StrongRootsScope
@@ -692,7 +680,7 @@
     gch->set_incremental_collection_failed();
 
     // Inform the next generation that a promotion failure occurred.
-    _next_gen->promotion_failure_occurred();
+    _old_gen->promotion_failure_occurred();
     gc_tracer.report_promotion_failed(_promotion_failed_info);
 
     // Reset the PromotionFailureALot counters.
@@ -797,7 +785,7 @@
 
   // Otherwise try allocating obj tenured
   if (obj == NULL) {
-    obj = _next_gen->promote(old, s);
+    obj = _old_gen->promote(old, s);
     if (obj == NULL) {
       handle_promotion_failure(old);
       return old;
@@ -866,8 +854,10 @@
 
 void DefNewGeneration::contribute_scratch(ScratchBlock*& list, Generation* requestor,
                                          size_t max_alloc_words) {
-  if (requestor == this || _promotion_failed) return;
-  assert(requestor->level() > level(), "DefNewGeneration must be youngest");
+  if (requestor == this || _promotion_failed) {
+    return;
+  }
+  assert(requestor == GenCollectedHeap::heap()->old_gen(), "We should not call our own generation");
 
   /* $$$ Assert this?  "trace" is a "MarkSweep" function so that's not appropriate.
   if (to_space->top() > to_space->bottom()) {
@@ -902,11 +892,11 @@
     }
     return false;
   }
-  if (_next_gen == NULL) {
+  if (_old_gen == NULL) {
     GenCollectedHeap* gch = GenCollectedHeap::heap();
-    _next_gen = gch->next_gen(this);
+    _old_gen = gch->old_gen();
   }
-  return _next_gen->promotion_attempt_is_safe(used());
+  return _old_gen->promotion_attempt_is_safe(used());
 }
 
 void DefNewGeneration::gc_epilogue(bool full) {
@@ -1026,8 +1016,7 @@
   return eden();
 }
 
-HeapWord* DefNewGeneration::allocate(size_t word_size,
-                                     bool is_tlab) {
+HeapWord* DefNewGeneration::allocate(size_t word_size, bool is_tlab) {
   // This is the slow-path allocation for the DefNewGeneration.
   // Most allocations are fast-path in compiled code.
   // We try to allocate from the eden.  If that works, we are happy.
@@ -1035,17 +1024,17 @@
   // have to use it here, as well.
   HeapWord* result = eden()->par_allocate(word_size);
   if (result != NULL) {
-    if (CMSEdenChunksRecordAlways && _next_gen != NULL) {
-      _next_gen->sample_eden_chunk();
+    if (CMSEdenChunksRecordAlways && _old_gen != NULL) {
+      _old_gen->sample_eden_chunk();
     }
     return result;
   }
   do {
     HeapWord* old_limit = eden()->soft_end();
     if (old_limit < eden()->end()) {
-      // Tell the next generation we reached a limit.
+      // Tell the old generation we reached a limit.
       HeapWord* new_limit =
-        next_gen()->allocation_limit_reached(eden(), eden()->top(), word_size);
+        _old_gen->allocation_limit_reached(eden(), eden()->top(), word_size);
       if (new_limit != NULL) {
         Atomic::cmpxchg_ptr(new_limit, eden()->soft_end_addr(), old_limit);
       } else {
@@ -1068,8 +1057,8 @@
   // circular dependency at compile time.
   if (result == NULL) {
     result = allocate_from_space(word_size);
-  } else if (CMSEdenChunksRecordAlways && _next_gen != NULL) {
-    _next_gen->sample_eden_chunk();
+  } else if (CMSEdenChunksRecordAlways && _old_gen != NULL) {
+    _old_gen->sample_eden_chunk();
   }
   return result;
 }
@@ -1077,8 +1066,8 @@
 HeapWord* DefNewGeneration::par_allocate(size_t word_size,
                                          bool is_tlab) {
   HeapWord* res = eden()->par_allocate(word_size);
-  if (CMSEdenChunksRecordAlways && _next_gen != NULL) {
-    _next_gen->sample_eden_chunk();
+  if (CMSEdenChunksRecordAlways && _old_gen != NULL) {
+    _old_gen->sample_eden_chunk();
   }
   return res;
 }