--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentG1Refine.cpp	Sat Jul 31 15:10:59 2010 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentG1Refine.cpp	Mon Aug 02 12:51:43 2010 -0700
@@ -339,7 +339,9 @@
   return res;
 }
 
-void ConcurrentG1Refine::clean_up_cache(int worker_i, G1RemSet* g1rs) {
+void ConcurrentG1Refine::clean_up_cache(int worker_i,
+                                        G1RemSet* g1rs,
+                                        DirtyCardQueue* into_cset_dcq) {
   assert(!use_cache(), "cache should be disabled");
   int start_idx;
 
@@ -353,7 +355,19 @@
       for (int i = start_idx; i < end_idx; i++) {
         jbyte* entry = _hot_cache[i];
         if (entry != NULL) {
-          g1rs->concurrentRefineOneCard(entry, worker_i);
+          if (g1rs->concurrentRefineOneCard(entry, worker_i, true)) {
+            // 'entry' contains references that point into the current
+            // collection set. We need to record 'entry' in the DCQS
+            // that's used for that purpose.
+            //
+            // The only time we care about recording cards that contain
+            // references that point into the collection set is during
+            // RSet updating while within an evacuation pause.
+            // In this case worker_i should be the id of a GC worker thread
+            assert(SafepointSynchronize::is_at_safepoint(), "not during an evacuation pause");
+            assert(worker_i < (int) DirtyCardQueueSet::num_par_ids(), "incorrect worker id");
+            into_cset_dcq->enqueue(entry);
+          }
         }
       }
     }

--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentG1Refine.hpp	Sat Jul 31 15:10:59 2010 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentG1Refine.hpp	Mon Aug 02 12:51:43 2010 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -184,7 +184,7 @@
   jbyte* cache_insert(jbyte* card_ptr, bool* defer);
 
   // Process the cached entries.
-  void clean_up_cache(int worker_i, G1RemSet* g1rs);
+  void clean_up_cache(int worker_i, G1RemSet* g1rs, DirtyCardQueue* into_cset_dcq);
 
   // Set up for parallel processing of the cards in the hot cache
   void clear_hot_cache_claimed_index() {

--- a/hotspot/src/share/vm/gc_implementation/g1/dirtyCardQueue.cpp	Sat Jul 31 15:10:59 2010 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/dirtyCardQueue.cpp	Mon Aug 02 12:51:43 2010 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -178,13 +178,14 @@
 }
 
 bool DirtyCardQueueSet::
-apply_closure_to_completed_buffer_helper(int worker_i,
+apply_closure_to_completed_buffer_helper(CardTableEntryClosure* cl,
+                                         int worker_i,
                                          BufferNode* nd) {
   if (nd != NULL) {
     void **buf = BufferNode::make_buffer_from_node(nd);
     size_t index = nd->index();
     bool b =
-      DirtyCardQueue::apply_closure_to_buffer(_closure, buf,
+      DirtyCardQueue::apply_closure_to_buffer(cl, buf,
                                               index, _sz,
                                               true, worker_i);
     if (b) {
@@ -199,15 +200,22 @@
   }
 }
 
+bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl,
+                                                          int worker_i,
+                                                          int stop_at,
+                                                          bool during_pause) {
+  assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause");
+  BufferNode* nd = get_completed_buffer(stop_at);
+  bool res = apply_closure_to_completed_buffer_helper(cl, worker_i, nd);
+  if (res) Atomic::inc(&_processed_buffers_rs_thread);
+  return res;
+}
+
 bool DirtyCardQueueSet::apply_closure_to_completed_buffer(int worker_i,
                                                           int stop_at,
-                                                          bool during_pause)
-{
-  assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause");
-  BufferNode* nd = get_completed_buffer(stop_at);
-  bool res = apply_closure_to_completed_buffer_helper(worker_i, nd);
-  if (res) Atomic::inc(&_processed_buffers_rs_thread);
-  return res;
+                                                          bool during_pause) {
+  return apply_closure_to_completed_buffer(_closure, worker_i,
+                                           stop_at, during_pause);
 }
 
 void DirtyCardQueueSet::apply_closure_to_all_completed_buffers() {
@@ -222,8 +230,8 @@
   }
 }
 
-void DirtyCardQueueSet::abandon_logs() {
-  assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
+// Deallocates any completed log buffers
+void DirtyCardQueueSet::clear() {
   BufferNode* buffers_to_delete = NULL;
   {
     MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
@@ -242,6 +250,12 @@
     buffers_to_delete = nd->next();
     deallocate_buffer(BufferNode::make_buffer_from_node(nd));
   }
+
+}
+
+void DirtyCardQueueSet::abandon_logs() {
+  assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
+  clear();
   // Since abandon is done only at safepoints, we can safely manipulate
   // these queues.
   for (JavaThread* t = Threads::first(); t; t = t->next()) {

--- a/hotspot/src/share/vm/gc_implementation/g1/dirtyCardQueue.hpp	Sat Jul 31 15:10:59 2010 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/dirtyCardQueue.hpp	Mon Aug 02 12:51:43 2010 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -123,7 +123,21 @@
                                          int stop_at = 0,
                                          bool during_pause = false);
 
-  bool apply_closure_to_completed_buffer_helper(int worker_i,
+  // If there exists some completed buffer, pop it, then apply the
+  // specified closure to all its elements, nulling out those elements
+  // processed.  If all elements are processed, returns "true".  If no
+  // completed buffers exist, returns false.  If a completed buffer exists,
+  // but is only partially completed before a "yield" happens, the
+  // partially completed buffer (with its processed elements set to NULL)
+  // is returned to the completed buffer set, and this call returns false.
+  bool apply_closure_to_completed_buffer(CardTableEntryClosure* cl,
+                                         int worker_i = 0,
+                                         int stop_at = 0,
+                                         bool during_pause = false);
+
+  // Helper routine for the above.
+  bool apply_closure_to_completed_buffer_helper(CardTableEntryClosure* cl,
+                                                int worker_i,
                                                 BufferNode* nd);
 
   BufferNode* get_completed_buffer(int stop_at);
@@ -136,6 +150,9 @@
     return &_shared_dirty_card_queue;
   }
 
+  // Deallocate any completed log buffers
+  void clear();
+
   // If a full collection is happening, reset partial logs, and ignore
   // completed ones: the full collection will make them all irrelevant.
   void abandon_logs();

--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Sat Jul 31 15:10:59 2010 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Mon Aug 02 12:51:43 2010 -0700
@@ -56,7 +56,12 @@
     _sts(sts), _g1rs(g1rs), _cg1r(cg1r), _concurrent(true)
   {}
   bool do_card_ptr(jbyte* card_ptr, int worker_i) {
-    _g1rs->concurrentRefineOneCard(card_ptr, worker_i);
+    bool oops_into_cset = _g1rs->concurrentRefineOneCard(card_ptr, worker_i, false);
+    // This path is executed by the concurrent refine or mutator threads,
+    // concurrently, and so we do not care if card_ptr contains references
+    // that point into the collection set.
+    assert(!oops_into_cset, "should be");
+
     if (_concurrent && _sts->should_yield()) {
       // Caller will actually yield.
       return false;
@@ -1322,6 +1327,7 @@
   SharedHeap(policy_),
   _g1_policy(policy_),
   _dirty_card_queue_set(false),
+  _into_cset_dirty_card_queue_set(false),
   _ref_processor(NULL),
   _process_strong_tasks(new SubTasksDone(G1H_PS_NumElements)),
   _bot_shared(NULL),
@@ -1572,6 +1578,16 @@
                                       Shared_DirtyCardQ_lock,
                                       &JavaThread::dirty_card_queue_set());
   }
+
+  // Initialize the card queue set used to hold cards containing
+  // references into the collection set.
+  _into_cset_dirty_card_queue_set.initialize(DirtyCardQ_CBL_mon,
+                                             DirtyCardQ_FL_lock,
+                                             -1, // never trigger processing
+                                             -1, // no limit on length
+                                             Shared_DirtyCardQ_lock,
+                                             &JavaThread::dirty_card_queue_set());
+
   // In case we're keeping closure specialization stats, initialize those
   // counts and that mechanism.
   SpecializationStats::clear();
@@ -1603,14 +1619,16 @@
   return _g1_committed.byte_size();
 }
 
-void G1CollectedHeap::iterate_dirty_card_closure(bool concurrent,
+void G1CollectedHeap::iterate_dirty_card_closure(CardTableEntryClosure* cl,
+                                                 DirtyCardQueue* into_cset_dcq,
+                                                 bool concurrent,
                                                  int worker_i) {
   // Clean cards in the hot card cache
-  concurrent_g1_refine()->clean_up_cache(worker_i, g1_rem_set());
+  concurrent_g1_refine()->clean_up_cache(worker_i, g1_rem_set(), into_cset_dcq);
 
   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
   int n_completed_buffers = 0;
-  while (dcqs.apply_closure_to_completed_buffer(worker_i, 0, true)) {
+  while (dcqs.apply_closure_to_completed_buffer(cl, worker_i, 0, true)) {
     n_completed_buffers++;
   }
   g1_policy()->record_update_rs_processed_buffers(worker_i,
@@ -3346,25 +3364,6 @@
   }
 };
 
-class UpdateRSetImmediate : public OopsInHeapRegionClosure {
-private:
-  G1CollectedHeap* _g1;
-  G1RemSet* _g1_rem_set;
-public:
-  UpdateRSetImmediate(G1CollectedHeap* g1) :
-    _g1(g1), _g1_rem_set(g1->g1_rem_set()) {}
-
-  virtual void do_oop(narrowOop* p) { do_oop_work(p); }
-  virtual void do_oop(      oop* p) { do_oop_work(p); }
-  template <class T> void do_oop_work(T* p) {
-    assert(_from->is_in_reserved(p), "paranoia");
-    T heap_oop = oopDesc::load_heap_oop(p);
-    if (!oopDesc::is_null(heap_oop) && !_from->is_survivor()) {
-      _g1_rem_set->par_write_ref(_from, p, 0);
-    }
-  }
-};
-
 class UpdateRSetDeferred : public OopsInHeapRegionClosure {
 private:
   G1CollectedHeap* _g1;
@@ -3389,8 +3388,6 @@
   }
 };
 
-
-
 class RemoveSelfPointerClosure: public ObjectClosure {
 private:
   G1CollectedHeap* _g1;
@@ -3453,7 +3450,7 @@
 };
 
 void G1CollectedHeap::remove_self_forwarding_pointers() {
-  UpdateRSetImmediate immediate_update(_g1h);
+  UpdateRSetImmediate immediate_update(_g1h->g1_rem_set());
   DirtyCardQueue dcq(&_g1h->dirty_card_queue_set());
   UpdateRSetDeferred deferred_update(_g1h, &dcq);
   OopsInHeapRegionClosure *cl;

--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Sat Jul 31 15:10:59 2010 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Mon Aug 02 12:51:43 2010 -0700
@@ -505,6 +505,12 @@
   // A function to check the consistency of dirty card logs.
   void check_ct_logs_at_safepoint();
 
+  // A DirtyCardQueueSet that is used to hold cards that contain
+  // references into the current collection set. This is used to
+  // update the remembered sets of the regions in the collection
+  // set in the event of an evacuation failure.
+  DirtyCardQueueSet _into_cset_dirty_card_queue_set;
+
   // After a collection pause, make the regions in the CS into free
   // regions.
   void free_collection_set(HeapRegion* cs_head);
@@ -661,6 +667,13 @@
   // A set of cards where updates happened during the GC
   DirtyCardQueueSet& dirty_card_queue_set() { return _dirty_card_queue_set; }
 
+  // A DirtyCardQueueSet that is used to hold cards that contain
+  // references into the current collection set. This is used to
+  // update the remembered sets of the regions in the collection
+  // set in the event of an evacuation failure.
+  DirtyCardQueueSet& into_cset_dirty_card_queue_set()
+        { return _into_cset_dirty_card_queue_set; }
+
   // Create a G1CollectedHeap with the specified policy.
   // Must call the initialize method afterwards.
   // May not return if something goes wrong.
@@ -715,7 +728,9 @@
     OrderAccess::fence();
   }
 
-  void iterate_dirty_card_closure(bool concurrent, int worker_i);
+  void iterate_dirty_card_closure(CardTableEntryClosure* cl,
+                                  DirtyCardQueue* into_cset_dcq,
+                                  bool concurrent, int worker_i);
 
   // The shared block offset table array.
   G1BlockOffsetSharedArray* bot_shared() const { return _bot_shared; }

--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp	Sat Jul 31 15:10:59 2010 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp	Mon Aug 02 12:51:43 2010 -0700
@@ -238,7 +238,6 @@
   _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads];
 
   _par_last_scan_rs_times_ms = new double[_parallel_gc_threads];
-  _par_last_scan_new_refs_times_ms = new double[_parallel_gc_threads];
 
   _par_last_obj_copy_times_ms = new double[_parallel_gc_threads];
 
@@ -842,7 +841,6 @@
     _par_last_update_rs_times_ms[i] = -1234.0;
     _par_last_update_rs_processed_buffers[i] = -1234.0;
     _par_last_scan_rs_times_ms[i] = -1234.0;
-    _par_last_scan_new_refs_times_ms[i] = -1234.0;
     _par_last_obj_copy_times_ms[i] = -1234.0;
     _par_last_termination_times_ms[i] = -1234.0;
     _par_last_termination_attempts[i] = -1234.0;

--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp	Sat Jul 31 15:10:59 2010 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp	Mon Aug 02 12:51:43 2010 -0700
@@ -63,8 +63,6 @@
     define_num_seq(mark_stack_scan)
     define_num_seq(update_rs)
     define_num_seq(scan_rs)
-    define_num_seq(scan_new_refs) // Only for temp use; added to
-                                  // in parallel case.
     define_num_seq(obj_copy)
     define_num_seq(termination) // parallel only
     define_num_seq(parallel_other) // parallel only
@@ -177,7 +175,6 @@
   double* _par_last_update_rs_times_ms;
   double* _par_last_update_rs_processed_buffers;
   double* _par_last_scan_rs_times_ms;
-  double* _par_last_scan_new_refs_times_ms;
   double* _par_last_obj_copy_times_ms;
   double* _par_last_termination_times_ms;
   double* _par_last_termination_attempts;
@@ -933,14 +930,6 @@
     _par_last_scan_rs_times_ms[thread] = ms;
   }
 
-  void record_scan_new_refs_time(int thread, double ms) {
-    _par_last_scan_new_refs_times_ms[thread] = ms;
-  }
-
-  double get_scan_new_refs_time(int thread) {
-    return _par_last_scan_new_refs_times_ms[thread];
-  }
-
   void reset_obj_copy_time(int thread) {
     _par_last_obj_copy_times_ms[thread] = 0.0;
   }

--- a/hotspot/src/share/vm/gc_implementation/g1/g1OopClosures.inline.hpp	Sat Jul 31 15:10:59 2010 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1OopClosures.inline.hpp	Mon Aug 02 12:51:43 2010 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2007, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -37,7 +37,8 @@
       _g1->obj_in_cs(oopDesc::decode_heap_oop_not_null(heap_oop))) {
     _oc->do_oop(p);
 #if FILTERINTOCSCLOSURE_DOHISTOGRAMCOUNT
-    _dcto_cl->incr_count();
+    if (_dcto_cl != NULL)
+      _dcto_cl->incr_count();
 #endif
   }
 }
@@ -113,7 +114,10 @@
     if (_g1->in_cset_fast_test(obj)) {
       Prefetch::write(obj->mark_addr(), 0);
       Prefetch::read(obj->mark_addr(), (HeapWordSize*2));
+
+      // Place on the references queue
       _par_scan_state->push_on_queue(p);
     }
   }
 }
+

--- a/hotspot/src/share/vm/gc_implementation/g1/g1RemSet.cpp	Sat Jul 31 15:10:59 2010 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1RemSet.cpp	Mon Aug 02 12:51:43 2010 -0700
@@ -122,23 +122,24 @@
 HRInto_G1RemSet::HRInto_G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs)
   : G1RemSet(g1), _ct_bs(ct_bs), _g1p(_g1->g1_policy()),
     _cg1r(g1->concurrent_g1_refine()),
-    _par_traversal_in_progress(false), _new_refs(NULL),
+    _par_traversal_in_progress(false),
+    _cset_rs_update_cl(NULL),
     _cards_scanned(NULL), _total_cards_scanned(0)
 {
   _seq_task = new SubTasksDone(NumSeqTasks);
   guarantee(n_workers() > 0, "There should be some workers");
-  _new_refs = NEW_C_HEAP_ARRAY(GrowableArray<OopOrNarrowOopStar>*, n_workers());
+  _cset_rs_update_cl = NEW_C_HEAP_ARRAY(OopsInHeapRegionClosure*, n_workers());
   for (uint i = 0; i < n_workers(); i++) {
-    _new_refs[i] = new (ResourceObj::C_HEAP) GrowableArray<OopOrNarrowOopStar>(8192,true);
+    _cset_rs_update_cl[i] = NULL;
   }
 }
 
 HRInto_G1RemSet::~HRInto_G1RemSet() {
   delete _seq_task;
   for (uint i = 0; i < n_workers(); i++) {
-    delete _new_refs[i];
+    assert(_cset_rs_update_cl[i] == NULL, "it should be");
   }
-  FREE_C_HEAP_ARRAY(GrowableArray<OopOrNarrowOopStar>*, _new_refs);
+  FREE_C_HEAP_ARRAY(OopsInHeapRegionClosure*, _cset_rs_update_cl);
 }
 
 void CountNonCleanMemRegionClosure::do_MemRegion(MemRegion mr) {
@@ -306,12 +307,45 @@
   _g1p->record_scan_rs_time(worker_i, scan_rs_time_sec * 1000.0);
 }
 
-void HRInto_G1RemSet::updateRS(int worker_i) {
-  ConcurrentG1Refine* cg1r = _g1->concurrent_g1_refine();
+// Closure used for updating RSets and recording references that
+// point into the collection set. Only called during an
+// evacuation pause.
+
+class RefineRecordRefsIntoCSCardTableEntryClosure: public CardTableEntryClosure {
+  G1RemSet* _g1rs;
+  DirtyCardQueue* _into_cset_dcq;
+public:
+  RefineRecordRefsIntoCSCardTableEntryClosure(G1CollectedHeap* g1h,
+                                              DirtyCardQueue* into_cset_dcq) :
+    _g1rs(g1h->g1_rem_set()), _into_cset_dcq(into_cset_dcq)
+  {}
+  bool do_card_ptr(jbyte* card_ptr, int worker_i) {
+    // The only time we care about recording cards that
+    // contain references that point into the collection set
+    // is during RSet updating within an evacuation pause.
+    // In this case worker_i should be the id of a GC worker thread.
+    assert(SafepointSynchronize::is_at_safepoint(), "not during an evacuation pause");
+    assert(worker_i < (int) DirtyCardQueueSet::num_par_ids(), "should be a GC worker");
 
+    if (_g1rs->concurrentRefineOneCard(card_ptr, worker_i, true)) {
+      // 'card_ptr' contains references that point into the collection
+      // set. We need to record the card in the DCQS
+      // (G1CollectedHeap::into_cset_dirty_card_queue_set())
+      // that's used for that purpose.
+      //
+      // Enqueue the card
+      _into_cset_dcq->enqueue(card_ptr);
+    }
+    return true;
+  }
+};
+
+void HRInto_G1RemSet::updateRS(DirtyCardQueue* into_cset_dcq, int worker_i) {
   double start = os::elapsedTime();
-  // Apply the appropriate closure to all remaining log entries.
-  _g1->iterate_dirty_card_closure(false, worker_i);
+  // Apply the given closure to all remaining log entries.
+  RefineRecordRefsIntoCSCardTableEntryClosure into_cset_update_rs_cl(_g1, into_cset_dcq);
+  _g1->iterate_dirty_card_closure(&into_cset_update_rs_cl, into_cset_dcq, false, worker_i);
+
   // Now there should be no dirty cards.
   if (G1RSLogCheckCardTable) {
     CountNonCleanMemRegionClosure cl(_g1);
@@ -405,33 +439,6 @@
   }
 };
 
-template <class T> void
-HRInto_G1RemSet::scanNewRefsRS_work(OopsInHeapRegionClosure* oc,
-                                    int worker_i) {
-  double scan_new_refs_start_sec = os::elapsedTime();
-  G1CollectedHeap* g1h = G1CollectedHeap::heap();
-  CardTableModRefBS* ct_bs = (CardTableModRefBS*) (g1h->barrier_set());
-  for (int i = 0; i < _new_refs[worker_i]->length(); i++) {
-    T* p = (T*) _new_refs[worker_i]->at(i);
-    oop obj = oopDesc::load_decode_heap_oop(p);
-    // *p was in the collection set when p was pushed on "_new_refs", but
-    // another thread may have processed this location from an RS, so it
-    // might not point into the CS any longer.  If so, it's obviously been
-    // processed, and we don't need to do anything further.
-    if (g1h->obj_in_cs(obj)) {
-      HeapRegion* r = g1h->heap_region_containing(p);
-
-      DEBUG_ONLY(HeapRegion* to = g1h->heap_region_containing(obj));
-      oc->set_region(r);
-      // If "p" has already been processed concurrently, this is
-      // idempotent.
-      oc->do_oop(p);
-    }
-  }
-  double scan_new_refs_time_ms = (os::elapsedTime() - scan_new_refs_start_sec) * 1000.0;
-  _g1p->record_scan_new_refs_time(worker_i, scan_new_refs_time_ms);
-}
-
 void HRInto_G1RemSet::cleanupHRRS() {
   HeapRegionRemSet::cleanup();
 }
@@ -457,6 +464,26 @@
     count_cl.print_histo();
   }
 
+  // We cache the value of 'oc' closure into the appropriate slot in the
+  // _cset_rs_update_cl for this worker
+  assert(worker_i < (int)n_workers(), "sanity");
+  _cset_rs_update_cl[worker_i] = oc;
+
+  // A DirtyCardQueue that is used to hold cards containing references
+  // that point into the collection set. This DCQ is associated with a
+  // special DirtyCardQueueSet (see g1CollectedHeap.hpp).  Under normal
+  // circumstances (i.e. the pause successfully completes), these cards
+  // are just discarded (there's no need to update the RSets of regions
+  // that were in the collection set - after the pause these regions
+  // are wholly 'free' of live objects. In the event of an evacuation
+  // failure the cards/buffers in this queue set are:
+  // * passed to the DirtyCardQueueSet that is used to manage deferred
+  //   RSet updates, or
+  // * scanned for references that point into the collection set
+  //   and the RSet of the corresponding region in the collection set
+  //   is updated immediately.
+  DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set());
+
   if (ParallelGCThreads > 0) {
     // The two flags below were introduced temporarily to serialize
     // the updating and scanning of remembered sets. There are some
@@ -465,12 +492,10 @@
     // conditions, we'll revert back to parallel remembered set
     // updating and scanning. See CRs 6677707 and 6677708.
     if (G1UseParallelRSetUpdating || (worker_i == 0)) {
-      updateRS(worker_i);
-      scanNewRefsRS(oc, worker_i);
+      updateRS(&into_cset_dcq, worker_i);
     } else {
       _g1p->record_update_rs_processed_buffers(worker_i, 0.0);
       _g1p->record_update_rs_time(worker_i, 0.0);
-      _g1p->record_scan_new_refs_time(worker_i, 0.0);
     }
     if (G1UseParallelRSetScanning || (worker_i == 0)) {
       scanRS(oc, worker_i);
@@ -479,10 +504,12 @@
     }
   } else {
     assert(worker_i == 0, "invariant");
-    updateRS(0);
-    scanNewRefsRS(oc, 0);
+    updateRS(&into_cset_dcq, 0);
     scanRS(oc, 0);
   }
+
+  // We now clear the cached values of _cset_rs_update_cl for this worker
+  _cset_rs_update_cl[worker_i] = NULL;
 }
 
 void HRInto_G1RemSet::
@@ -519,49 +546,65 @@
   }
 };
 
-class UpdateRSetOopsIntoCSImmediate : public OopClosure {
-  G1CollectedHeap* _g1;
-public:
-  UpdateRSetOopsIntoCSImmediate(G1CollectedHeap* g1) : _g1(g1) { }
-  virtual void do_oop(narrowOop* p) { do_oop_work(p); }
-  virtual void do_oop(      oop* p) { do_oop_work(p); }
-  template <class T> void do_oop_work(T* p) {
-    HeapRegion* to = _g1->heap_region_containing(oopDesc::load_decode_heap_oop(p));
-    if (to->in_collection_set()) {
-      to->rem_set()->add_reference(p, 0);
-    }
-  }
-};
-
-class UpdateRSetOopsIntoCSDeferred : public OopClosure {
+// This closure, applied to a DirtyCardQueueSet, is used to immediately
+// update the RSets for the regions in the CSet. For each card it iterates
+// through the oops which coincide with that card. It scans the reference
+// fields in each oop; when it finds an oop that points into the collection
+// set, the RSet for the region containing the referenced object is updated.
+// Note: _par_traversal_in_progress in the G1RemSet must be FALSE; otherwise
+// the UpdateRSetImmediate closure will cause cards to be enqueued on to
+// the DCQS that we're iterating over, causing an infinite loop.
+class UpdateRSetCardTableEntryIntoCSetClosure: public CardTableEntryClosure {
   G1CollectedHeap* _g1;
   CardTableModRefBS* _ct_bs;
-  DirtyCardQueue* _dcq;
 public:
-  UpdateRSetOopsIntoCSDeferred(G1CollectedHeap* g1, DirtyCardQueue* dcq) :
-    _g1(g1), _ct_bs((CardTableModRefBS*)_g1->barrier_set()), _dcq(dcq) { }
-  virtual void do_oop(narrowOop* p) { do_oop_work(p); }
-  virtual void do_oop(      oop* p) { do_oop_work(p); }
-  template <class T> void do_oop_work(T* p) {
-    oop obj = oopDesc::load_decode_heap_oop(p);
-    if (_g1->obj_in_cs(obj)) {
-      size_t card_index = _ct_bs->index_for(p);
-      if (_ct_bs->mark_card_deferred(card_index)) {
-        _dcq->enqueue((jbyte*)_ct_bs->byte_for_index(card_index));
-      }
-    }
+  UpdateRSetCardTableEntryIntoCSetClosure(G1CollectedHeap* g1,
+                                          CardTableModRefBS* bs):
+    _g1(g1), _ct_bs(bs)
+  { }
+
+  bool do_card_ptr(jbyte* card_ptr, int worker_i) {
+    // Construct the region representing the card.
+    HeapWord* start = _ct_bs->addr_for(card_ptr);
+    // And find the region containing it.
+    HeapRegion* r = _g1->heap_region_containing(start);
+    assert(r != NULL, "unexpected null");
+
+    // Scan oops in the card looking for references into the collection set
+    HeapWord* end   = _ct_bs->addr_for(card_ptr + 1);
+    MemRegion scanRegion(start, end);
+
+    UpdateRSetImmediate update_rs_cl(_g1->g1_rem_set());
+    FilterIntoCSClosure update_rs_cset_oop_cl(NULL, _g1, &update_rs_cl);
+    FilterOutOfRegionClosure filter_then_update_rs_cset_oop_cl(r, &update_rs_cset_oop_cl);
+
+    // We can pass false as the "filter_young" parameter here as:
+    // * we should be in a STW pause,
+    // * the DCQS to which this closure is applied is used to hold
+    //   references that point into the collection set from the prior
+    //   RSet updating,
+    // * the post-write barrier shouldn't be logging updates to young
+    //   regions (but there is a situation where this can happen - see
+    //   the comment in HRInto_G1RemSet::concurrentRefineOneCard below -
+    //   that should not be applicable here), and
+    // * during actual RSet updating, the filtering of cards in young
+    //   regions in HeapRegion::oops_on_card_seq_iterate_careful is
+    //   employed.
+    // As a result, when this closure is applied to "refs into cset"
+    // DCQS, we shouldn't see any cards in young regions.
+    update_rs_cl.set_region(r);
+    HeapWord* stop_point =
+      r->oops_on_card_seq_iterate_careful(scanRegion,
+                                        &filter_then_update_rs_cset_oop_cl,
+                                        false /* filter_young */);
+
+    // Since this is performed in the event of an evacuation failure, we
+    // we shouldn't see a non-null stop point
+    assert(stop_point == NULL, "saw an unallocated region");
+    return true;
   }
 };
 
-template <class T> void HRInto_G1RemSet::new_refs_iterate_work(OopClosure* cl) {
-  for (size_t i = 0; i < n_workers(); i++) {
-    for (int j = 0; j < _new_refs[i]->length(); j++) {
-      T* p = (T*) _new_refs[i]->at(j);
-      cl->do_oop(p);
-    }
-  }
-}
-
 void HRInto_G1RemSet::cleanup_after_oops_into_collection_set_do() {
   guarantee( _cards_scanned != NULL, "invariant" );
   _total_cards_scanned = 0;
@@ -584,21 +627,38 @@
     set_par_traversal(false);
   }
 
+  DirtyCardQueueSet& into_cset_dcqs = _g1->into_cset_dirty_card_queue_set();
+  int into_cset_n_buffers = into_cset_dcqs.completed_buffers_num();
+
   if (_g1->evacuation_failed()) {
-    // Restore remembered sets for the regions pointing into
-    // the collection set.
+    // Restore remembered sets for the regions pointing into the collection set.
+
     if (G1DeferredRSUpdate) {
-      DirtyCardQueue dcq(&_g1->dirty_card_queue_set());
-      UpdateRSetOopsIntoCSDeferred deferred_update(_g1, &dcq);
-      new_refs_iterate(&deferred_update);
+      // If deferred RS updates are enabled then we just need to transfer
+      // the completed buffers from (a) the DirtyCardQueueSet used to hold
+      // cards that contain references that point into the collection set
+      // to (b) the DCQS used to hold the deferred RS updates
+      _g1->dirty_card_queue_set().merge_bufferlists(&into_cset_dcqs);
     } else {
-      UpdateRSetOopsIntoCSImmediate immediate_update(_g1);
-      new_refs_iterate(&immediate_update);
+
+      CardTableModRefBS* bs = (CardTableModRefBS*)_g1->barrier_set();
+      UpdateRSetCardTableEntryIntoCSetClosure update_rs_cset_immediate(_g1, bs);
+
+      int n_completed_buffers = 0;
+      while (into_cset_dcqs.apply_closure_to_completed_buffer(&update_rs_cset_immediate,
+                                                    0, 0, true)) {
+        n_completed_buffers++;
+      }
+      assert(n_completed_buffers == into_cset_n_buffers, "missed some buffers");
     }
   }
-  for (uint i = 0; i < n_workers(); i++) {
-    _new_refs[i]->clear();
-  }
+
+  // Free any completed buffers in the DirtyCardQueueSet used to hold cards
+  // which contain references that point into the collection.
+  _g1->into_cset_dirty_card_queue_set().clear();
+  assert(_g1->into_cset_dirty_card_queue_set().completed_buffers_num() == 0,
+         "all buffers should be freed");
+  _g1->into_cset_dirty_card_queue_set().clear_n_completed_buffers();
 
   assert(!_par_traversal_in_progress, "Invariant between iterations.");
 }
@@ -652,7 +712,43 @@
 
 static IntHistogram out_of_histo(50, 50);
 
-void HRInto_G1RemSet::concurrentRefineOneCard_impl(jbyte* card_ptr, int worker_i) {
+class TriggerClosure : public OopClosure {
+  bool _trigger;
+public:
+  TriggerClosure() : _trigger(false) { }
+  bool value() const { return _trigger; }
+  template <class T> void do_oop_nv(T* p) { _trigger = true; }
+  virtual void do_oop(oop* p)        { do_oop_nv(p); }
+  virtual void do_oop(narrowOop* p)  { do_oop_nv(p); }
+};
+
+class InvokeIfNotTriggeredClosure: public OopClosure {
+  TriggerClosure* _t;
+  OopClosure* _oc;
+public:
+  InvokeIfNotTriggeredClosure(TriggerClosure* t, OopClosure* oc):
+    _t(t), _oc(oc) { }
+  template <class T> void do_oop_nv(T* p) {
+    if (!_t->value()) _oc->do_oop(p);
+  }
+  virtual void do_oop(oop* p)        { do_oop_nv(p); }
+  virtual void do_oop(narrowOop* p)  { do_oop_nv(p); }
+};
+
+class Mux2Closure : public OopClosure {
+  OopClosure* _c1;
+  OopClosure* _c2;
+public:
+  Mux2Closure(OopClosure *c1, OopClosure *c2) : _c1(c1), _c2(c2) { }
+  template <class T> void do_oop_nv(T* p) {
+    _c1->do_oop(p); _c2->do_oop(p);
+  }
+  virtual void do_oop(oop* p)        { do_oop_nv(p); }
+  virtual void do_oop(narrowOop* p)  { do_oop_nv(p); }
+};
+
+bool HRInto_G1RemSet::concurrentRefineOneCard_impl(jbyte* card_ptr, int worker_i,
+                                                   bool check_for_refs_into_cset) {
   // Construct the region representing the card.
   HeapWord* start = _ct_bs->addr_for(card_ptr);
   // And find the region containing it.
@@ -669,7 +765,16 @@
 
   UpdateRSOopClosure update_rs_oop_cl(this, worker_i);
   update_rs_oop_cl.set_from(r);
-  FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r, &update_rs_oop_cl);
+
+  TriggerClosure trigger_cl;
+  FilterIntoCSClosure into_cs_cl(NULL, _g1, &trigger_cl);
+  InvokeIfNotTriggeredClosure invoke_cl(&trigger_cl, &into_cs_cl);
+  Mux2Closure mux(&invoke_cl, &update_rs_oop_cl);
+
+  FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r,
+                        (check_for_refs_into_cset ?
+                                (OopClosure*)&mux :
+                                (OopClosure*)&update_rs_oop_cl));
 
   // Undirty the card.
   *card_ptr = CardTableModRefBS::clean_card_val();
@@ -717,11 +822,18 @@
     out_of_histo.add_entry(filter_then_update_rs_oop_cl.out_of_region());
     _conc_refine_cards++;
   }
+
+  return trigger_cl.value();
 }
 
-void HRInto_G1RemSet::concurrentRefineOneCard(jbyte* card_ptr, int worker_i) {
+bool HRInto_G1RemSet::concurrentRefineOneCard(jbyte* card_ptr, int worker_i,
+                                              bool check_for_refs_into_cset) {
   // If the card is no longer dirty, nothing to do.
-  if (*card_ptr != CardTableModRefBS::dirty_card_val()) return;
+  if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
+    // No need to return that this card contains refs that point
+    // into the collection set.
+    return false;
+  }
 
   // Construct the region representing the card.
   HeapWord* start = _ct_bs->addr_for(card_ptr);
@@ -729,7 +841,9 @@
   HeapRegion* r = _g1->heap_region_containing(start);
   if (r == NULL) {
     guarantee(_g1->is_in_permanent(start), "Or else where?");
-    return;  // Not in the G1 heap (might be in perm, for example.)
+    // Again no need to return that this card contains refs that
+    // point into the collection set.
+    return false;  // Not in the G1 heap (might be in perm, for example.)
   }
   // Why do we have to check here whether a card is on a young region,
   // given that we dirty young regions and, as a result, the
@@ -743,7 +857,7 @@
   // and it doesn't happen often, but it can happen. So, the extra
   // check below filters out those cards.
   if (r->is_young()) {
-    return;
+    return false;
   }
   // While we are processing RSet buffers during the collection, we
   // actually don't want to scan any cards on the collection set,
@@ -756,7 +870,7 @@
   // however, that if evacuation fails, we have to scan any objects
   // that were not moved and create any missing entries.
   if (r->in_collection_set()) {
-    return;
+    return false;
   }
 
   // Should we defer processing the card?
@@ -797,8 +911,14 @@
   //                  cache.
   //                  Immediately process res; no need to process card_ptr.
 
+
   jbyte* res = card_ptr;
   bool defer = false;
+
+  // This gets set to true if the card being refined has references
+  // that point into the collection set.
+  bool oops_into_cset = false;
+
   if (_cg1r->use_cache()) {
     jbyte* res = _cg1r->cache_insert(card_ptr, &defer);
     if (res != NULL && (res != card_ptr || defer)) {
@@ -815,14 +935,31 @@
         // Process card pointer we get back from the hot card cache. This
         // will check whether the region containing the card is young
         // _after_ checking that the region has been allocated from.
-        concurrentRefineOneCard_impl(res, worker_i);
+        oops_into_cset = concurrentRefineOneCard_impl(res, worker_i,
+                                                      false /* check_for_refs_into_cset */);
+        // The above call to concurrentRefineOneCard_impl is only
+        // performed if the hot card cache is enabled. This cache is
+        // disabled during an evacuation pause - which is the only
+        // time when we need know if the card contains references
+        // that point into the collection set. Also when the hot card
+        // cache is enabled, this code is executed by the concurrent
+        // refine threads - rather than the GC worker threads - and
+        // concurrentRefineOneCard_impl will return false.
+        assert(!oops_into_cset, "should not see true here");
       }
     }
   }
 
   if (!defer) {
-    concurrentRefineOneCard_impl(card_ptr, worker_i);
+    oops_into_cset =
+      concurrentRefineOneCard_impl(card_ptr, worker_i, check_for_refs_into_cset);
+    // We should only be detecting that the card contains references
+    // that point into the collection set if the current thread is
+    // a GC worker thread.
+    assert(!oops_into_cset || SafepointSynchronize::is_at_safepoint(),
+           "invalid result at non safepoint");
   }
+  return oops_into_cset;
 }
 
 class HRRSStatsIter: public HeapRegionClosure {
@@ -920,6 +1057,7 @@
 
   }
 }
+
 void HRInto_G1RemSet::prepare_for_verify() {
   if (G1HRRSFlushLogBuffersOnVerify &&
       (VerifyBeforeGC || VerifyAfterGC)
@@ -932,7 +1070,9 @@
     }
     bool cg1r_use_cache = _cg1r->use_cache();
     _cg1r->set_use_cache(false);
-    updateRS(0);
+    DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set());
+    updateRS(&into_cset_dcq, 0);
+    _g1->into_cset_dirty_card_queue_set().clear();
     _cg1r->set_use_cache(cg1r_use_cache);
 
     assert(JavaThread::dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed");

--- a/hotspot/src/share/vm/gc_implementation/g1/g1RemSet.hpp	Sat Jul 31 15:10:59 2010 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1RemSet.hpp	Mon Aug 02 12:51:43 2010 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -83,7 +83,13 @@
   // Refine the card corresponding to "card_ptr".  If "sts" is non-NULL,
   // join and leave around parts that must be atomic wrt GC.  (NULL means
   // being done at a safepoint.)
-  virtual void concurrentRefineOneCard(jbyte* card_ptr, int worker_i) {}
+  // With some implementations of this routine, when check_for_refs_into_cset
+  // is true, a true result may be returned if the given card contains oops
+  // that have references into the current collection set.
+  virtual bool concurrentRefineOneCard(jbyte* card_ptr, int worker_i,
+                                       bool check_for_refs_into_cset) {
+    return false;
+  }
 
   // Print any relevant summary info.
   virtual void print_summary_info() {}
@@ -143,23 +149,21 @@
   size_t              _total_cards_scanned;
 
   // _par_traversal_in_progress is "true" iff a parallel traversal is in
-  // progress.  If so, then cards added to remembered sets should also have
-  // their references into the collection summarized in "_new_refs".
+  // progress.
   bool _par_traversal_in_progress;
   void set_par_traversal(bool b) { _par_traversal_in_progress = b; }
-  GrowableArray<OopOrNarrowOopStar>** _new_refs;
-  template <class T> void new_refs_iterate_work(OopClosure* cl);
-  void new_refs_iterate(OopClosure* cl) {
-    if (UseCompressedOops) {
-      new_refs_iterate_work<narrowOop>(cl);
-    } else {
-      new_refs_iterate_work<oop>(cl);
-    }
-  }
+
+  // Used for caching the closure that is responsible for scanning
+  // references into the collection set.
+  OopsInHeapRegionClosure** _cset_rs_update_cl;
 
   // The routine that performs the actual work of refining a dirty
   // card.
-  void concurrentRefineOneCard_impl(jbyte* card_ptr, int worker_i);
+  // If check_for_refs_into_refs is true then a true result is returned
+  // if the card contains oops that have references into the current
+  // collection set.
+  bool concurrentRefineOneCard_impl(jbyte* card_ptr, int worker_i,
+                                    bool check_for_refs_into_cset);
 
 protected:
   template <class T> void write_ref_nv(HeapRegion* from, T* p);
@@ -188,7 +192,7 @@
       scanNewRefsRS_work<oop>(oc, worker_i);
     }
   }
-  void updateRS(int worker_i);
+  void updateRS(DirtyCardQueue* into_cset_dcq, int worker_i);
   HeapRegion* calculateStartRegion(int i);
 
   HRInto_G1RemSet* as_HRInto_G1RemSet() { return this; }
@@ -219,7 +223,11 @@
   void scrub_par(BitMap* region_bm, BitMap* card_bm,
                  int worker_num, int claim_val);
 
-  virtual void concurrentRefineOneCard(jbyte* card_ptr, int worker_i);
+  // If check_for_refs_into_cset is true then a true result is returned
+  // if the card contains oops that have references into the current
+  // collection set.
+  virtual bool concurrentRefineOneCard(jbyte* card_ptr, int worker_i,
+                                       bool check_for_refs_into_cset);
 
   virtual void print_summary_info();
   virtual void prepare_for_verify();
@@ -265,3 +273,16 @@
   //  bool idempotent() { return true; }
   bool apply_to_weak_ref_discovered_field() { return true; }
 };
+
+class UpdateRSetImmediate: public OopsInHeapRegionClosure {
+private:
+  G1RemSet* _g1_rem_set;
+
+  template <class T> void do_oop_work(T* p);
+public:
+  UpdateRSetImmediate(G1RemSet* rs) :
+    _g1_rem_set(rs) {}
+
+  virtual void do_oop(narrowOop* p) { do_oop_work(p); }
+  virtual void do_oop(      oop* p) { do_oop_work(p); }
+};

--- a/hotspot/src/share/vm/gc_implementation/g1/g1RemSet.inline.hpp	Sat Jul 31 15:10:59 2010 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1RemSet.inline.hpp	Mon Aug 02 12:51:43 2010 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -56,19 +56,25 @@
     assert(Universe::heap()->is_in_reserved(obj), "must be in heap");
   }
 #endif // ASSERT
-  assert(from == NULL || from->is_in_reserved(p),
-         "p is not in from");
+
+  assert(from == NULL || from->is_in_reserved(p), "p is not in from");
+
   HeapRegion* to = _g1->heap_region_containing(obj);
   // The test below could be optimized by applying a bit op to to and from.
   if (to != NULL && from != NULL && from != to) {
-    // There is a tricky infinite loop if we keep pushing
-    // self forwarding pointers onto our _new_refs list.
     // The _par_traversal_in_progress flag is true during the collection pause,
-    // false during the evacuation failure handing.
+    // false during the evacuation failure handing. This should avoid a
+    // potential loop if we were to add the card containing 'p' to the DCQS
+    // that's used to regenerate the remembered sets for the collection set,
+    // in the event of an evacuation failure, here. The UpdateRSImmediate
+    // closure will eventally call this routine.
     if (_par_traversal_in_progress &&
         to->in_collection_set() && !self_forwarded(obj)) {
-      _new_refs[tid]->push((void*)p);
-      // Deferred updates to the Cset are either discarded (in the normal case),
+
+      assert(_cset_rs_update_cl[tid] != NULL, "should have been set already");
+      _cset_rs_update_cl[tid]->do_oop(p);
+
+      // Deferred updates to the CSet are either discarded (in the normal case),
       // or processed (if an evacuation failure occurs) at the end
       // of the collection.
       // See HRInto_G1RemSet::cleanup_after_oops_into_collection_set_do().
@@ -89,3 +95,12 @@
   assert(_from != NULL, "from region must be non-NULL");
   _rs->par_write_ref(_from, p, _worker_i);
 }
+
+template <class T> inline void UpdateRSetImmediate::do_oop_work(T* p) {
+  assert(_from->is_in_reserved(p), "paranoia");
+  T heap_oop = oopDesc::load_heap_oop(p);
+  if (!oopDesc::is_null(heap_oop) && !_from->is_survivor()) {
+    _g1_rem_set->par_write_ref(_from, p, 0);
+  }
+}
+

--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp	Sat Jul 31 15:10:59 2010 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp	Mon Aug 02 12:51:43 2010 -0700
@@ -683,6 +683,8 @@
     return NULL;
   }
 
+  assert(!is_young(), "check value of filter_young");
+
   // We used to use "block_start_careful" here.  But we're actually happy
   // to update the BOT while we do this...
   HeapWord* cur = block_start(mr.start());

--- a/hotspot/src/share/vm/gc_implementation/includeDB_gc_g1	Sat Jul 31 15:10:59 2010 +0100
+++ b/hotspot/src/share/vm/gc_implementation/includeDB_gc_g1	Mon Aug 02 12:51:43 2010 -0700
@@ -1,5 +1,5 @@
 //
-// Copyright (c) 2004, 2009, Oracle and/or its affiliates. All rights reserved.
+// Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
 // DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 //
 // This code is free software; you can redistribute it and/or modify it
@@ -241,6 +241,7 @@
 
 g1MMUTracker.hpp			debug.hpp
 g1MMUTracker.hpp			allocation.hpp
+
 g1RemSet.cpp				bufferingOopClosure.hpp
 g1RemSet.cpp				concurrentG1Refine.hpp
 g1RemSet.cpp				concurrentG1RefineThread.hpp