changeset 577:58054a18d735

6484959: G1: introduce survivor spaces 6797754: G1: combined bugfix Summary: Implemented a policy to control G1 survivor space parameters. Reviewed-by: tonyp, iveresov
author apetrusenko
date Fri, 06 Feb 2009 01:38:50 +0300
parents 82a980778b92
children 05c6d52fa7a9
files src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp src/share/vm/gc_implementation/g1/g1RemSet.cpp src/share/vm/gc_implementation/g1/g1_globals.hpp src/share/vm/gc_implementation/g1/heapRegion.hpp src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp src/share/vm/gc_implementation/g1/survRateGroup.cpp src/share/vm/gc_implementation/g1/survRateGroup.hpp src/share/vm/gc_implementation/includeDB_gc_g1 src/share/vm/gc_implementation/shared/ageTable.cpp src/share/vm/gc_implementation/shared/ageTable.hpp
diffstat 13 files changed, 315 insertions(+), 133 deletions(-) [+]
line wrap: on
line diff
--- a/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Thu Feb 05 11:42:10 2009 -0800
+++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Fri Feb 06 01:38:50 2009 +0300
@@ -141,7 +141,7 @@
     _scan_only_head(NULL), _scan_only_tail(NULL), _curr_scan_only(NULL),
     _length(0), _scan_only_length(0),
     _last_sampled_rs_lengths(0),
-    _survivor_head(NULL), _survivors_tail(NULL), _survivor_length(0)
+    _survivor_head(NULL), _survivor_tail(NULL), _survivor_length(0)
 {
   guarantee( check_list_empty(false), "just making sure..." );
 }
@@ -159,16 +159,15 @@
 }
 
 void YoungList::add_survivor_region(HeapRegion* hr) {
-  assert(!hr->is_survivor(), "should not already be for survived");
+  assert(hr->is_survivor(), "should be flagged as survivor region");
   assert(hr->get_next_young_region() == NULL, "cause it should!");
 
   hr->set_next_young_region(_survivor_head);
   if (_survivor_head == NULL) {
-    _survivors_tail = hr;
+    _survivor_tail = hr;
   }
   _survivor_head = hr;
 
-  hr->set_survivor();
   ++_survivor_length;
 }
 
@@ -239,7 +238,7 @@
 
   empty_list(_survivor_head);
   _survivor_head = NULL;
-  _survivors_tail = NULL;
+  _survivor_tail = NULL;
   _survivor_length = 0;
 
   _last_sampled_rs_lengths = 0;
@@ -391,6 +390,7 @@
 
   // Add survivor regions to SurvRateGroup.
   _g1h->g1_policy()->note_start_adding_survivor_regions();
+  _g1h->g1_policy()->finished_recalculating_age_indexes(true /* is_survivors */);
   for (HeapRegion* curr = _survivor_head;
        curr != NULL;
        curr = curr->get_next_young_region()) {
@@ -401,7 +401,7 @@
   if (_survivor_head != NULL) {
     _head           = _survivor_head;
     _length         = _survivor_length + _scan_only_length;
-    _survivors_tail->set_next_young_region(_scan_only_head);
+    _survivor_tail->set_next_young_region(_scan_only_head);
   } else {
     _head           = _scan_only_head;
     _length         = _scan_only_length;
@@ -418,9 +418,9 @@
   _curr_scan_only   = NULL;
 
   _survivor_head    = NULL;
-  _survivors_tail   = NULL;
+  _survivor_tail   = NULL;
   _survivor_length  = 0;
-  _g1h->g1_policy()->finished_recalculating_age_indexes();
+  _g1h->g1_policy()->finished_recalculating_age_indexes(false /* is_survivors */);
 
   assert(check_list_well_formed(), "young list should be well formed");
 }
@@ -553,7 +553,7 @@
   if (_gc_alloc_region_counts[purpose] < g1_policy()->max_regions(purpose)) {
     alloc_region = newAllocRegion_work(word_size, true, zero_filled);
     if (purpose == GCAllocForSurvived && alloc_region != NULL) {
-      _young_list->add_survivor_region(alloc_region);
+      alloc_region->set_survivor();
     }
     ++_gc_alloc_region_counts[purpose];
   } else {
@@ -2593,6 +2593,9 @@
         _young_list->print();
 #endif // SCAN_ONLY_VERBOSE
 
+        g1_policy()->record_survivor_regions(_young_list->survivor_length(),
+                                             _young_list->first_survivor_region(),
+                                             _young_list->last_survivor_region());
         _young_list->reset_auxilary_lists();
       }
     } else {
@@ -2619,7 +2622,9 @@
 #endif // SCAN_ONLY_VERBOSE
 
     double end_time_sec = os::elapsedTime();
-    g1_policy()->record_pause_time((end_time_sec - start_time_sec)*1000.0);
+    if (!evacuation_failed()) {
+      g1_policy()->record_pause_time((end_time_sec - start_time_sec)*1000.0);
+    }
     GCOverheadReporter::recordSTWEnd(end_time_sec);
     g1_policy()->record_collection_pause_end(popular_region != NULL,
                                              abandoned);
@@ -2754,6 +2759,13 @@
     _gc_alloc_region_list = r->next_gc_alloc_region();
     r->set_next_gc_alloc_region(NULL);
     r->set_is_gc_alloc_region(false);
+    if (r->is_survivor()) {
+      if (r->is_empty()) {
+        r->set_not_young();
+      } else {
+        _young_list->add_survivor_region(r);
+      }
+    }
     if (r->is_empty()) {
       ++_free_regions;
     }
@@ -3150,6 +3162,20 @@
   return block;
 }
 
+void G1CollectedHeap::retire_alloc_region(HeapRegion* alloc_region,
+                                            bool par) {
+  // Another thread might have obtained alloc_region for the given
+  // purpose, and might be attempting to allocate in it, and might
+  // succeed.  Therefore, we can't do the "finalization" stuff on the
+  // region below until we're sure the last allocation has happened.
+  // We ensure this by allocating the remaining space with a garbage
+  // object.
+  if (par) par_allocate_remaining_space(alloc_region);
+  // Now we can do the post-GC stuff on the region.
+  alloc_region->note_end_of_copying();
+  g1_policy()->record_after_bytes(alloc_region->used());
+}
+
 HeapWord*
 G1CollectedHeap::allocate_during_gc_slow(GCAllocPurpose purpose,
                                          HeapRegion*    alloc_region,
@@ -3167,16 +3193,7 @@
     // Otherwise, continue; this new region is empty, too.
   }
   assert(alloc_region != NULL, "We better have an allocation region");
-  // Another thread might have obtained alloc_region for the given
-  // purpose, and might be attempting to allocate in it, and might
-  // succeed.  Therefore, we can't do the "finalization" stuff on the
-  // region below until we're sure the last allocation has happened.
-  // We ensure this by allocating the remaining space with a garbage
-  // object.
-  if (par) par_allocate_remaining_space(alloc_region);
-  // Now we can do the post-GC stuff on the region.
-  alloc_region->note_end_of_copying();
-  g1_policy()->record_after_bytes(alloc_region->used());
+  retire_alloc_region(alloc_region, par);
 
   if (_gc_alloc_region_counts[purpose] >= g1_policy()->max_regions(purpose)) {
     // Cannot allocate more regions for the given purpose.
@@ -3185,7 +3202,7 @@
     if (purpose != alt_purpose) {
       HeapRegion* alt_region = _gc_alloc_regions[alt_purpose];
       // Has not the alternative region been aliased?
-      if (alloc_region != alt_region) {
+      if (alloc_region != alt_region && alt_region != NULL) {
         // Try to allocate in the alternative region.
         if (par) {
           block = alt_region->par_allocate(word_size);
@@ -3194,9 +3211,10 @@
         }
         // Make an alias.
         _gc_alloc_regions[purpose] = _gc_alloc_regions[alt_purpose];
-      }
-      if (block != NULL) {
-        return block;
+        if (block != NULL) {
+          return block;
+        }
+        retire_alloc_region(alt_region, par);
       }
       // Both the allocation region and the alternative one are full
       // and aliased, replace them with a new allocation region.
@@ -3497,6 +3515,7 @@
   OverflowQueue* _overflowed_refs;
 
   G1ParGCAllocBuffer _alloc_buffers[GCAllocPurposeCount];
+  ageTable           _age_table;
 
   size_t           _alloc_buffer_waste;
   size_t           _undo_waste;
@@ -3538,6 +3557,7 @@
       _refs(g1h->task_queue(queue_num)),
       _hash_seed(17), _queue_num(queue_num),
       _term_attempts(0),
+      _age_table(false),
 #if G1_DETAILED_STATS
       _pushes(0), _pops(0), _steals(0),
       _steal_attempts(0),  _overflow_pushes(0),
@@ -3572,8 +3592,9 @@
 
   RefToScanQueue*   refs()            { return _refs;             }
   OverflowQueue*    overflowed_refs() { return _overflowed_refs;  }
-
-  inline G1ParGCAllocBuffer* alloc_buffer(GCAllocPurpose purpose) {
+  ageTable*         age_table()       { return &_age_table;       }
+
+  G1ParGCAllocBuffer* alloc_buffer(GCAllocPurpose purpose) {
     return &_alloc_buffers[purpose];
   }
 
@@ -3834,7 +3855,9 @@
           (!from_region->is_young() && young_index == 0), "invariant" );
   G1CollectorPolicy* g1p = _g1->g1_policy();
   markOop m = old->mark();
-  GCAllocPurpose alloc_purpose = g1p->evacuation_destination(from_region, m->age(),
+  int age = m->has_displaced_mark_helper() ? m->displaced_mark_helper()->age()
+                                           : m->age();
+  GCAllocPurpose alloc_purpose = g1p->evacuation_destination(from_region, age,
                                                              word_sz);
   HeapWord* obj_ptr = _par_scan_state->allocate(alloc_purpose, word_sz);
   oop       obj     = oop(obj_ptr);
@@ -3872,9 +3895,12 @@
         obj->incr_age();
       } else {
         m = m->incr_age();
+        obj->set_mark(m);
       }
+      _par_scan_state->age_table()->add(obj, word_sz);
+    } else {
+      obj->set_mark(m);
     }
-    obj->set_mark(m);
 
     // preserve "next" mark bit
     if (_g1->mark_in_progress() && !_g1->is_obj_ill(old)) {
@@ -4129,6 +4155,9 @@
       _g1h->g1_policy()->record_obj_copy_time(i, elapsed_ms-term_ms);
       _g1h->g1_policy()->record_termination_time(i, term_ms);
     }
+    if (G1UseSurvivorSpace) {
+      _g1h->g1_policy()->record_thread_age_table(pss.age_table());
+    }
     _g1h->update_surviving_young_words(pss.surviving_young_words()+1);
 
     // Clean up any par-expanded rem sets.
@@ -4368,7 +4397,7 @@
   // Is this the right thing to do here?  We don't save marks
   // on individual heap regions when we allocate from
   // them in parallel, so this seems like the correct place for this.
-  all_alloc_regions_note_end_of_copying();
+  retire_all_alloc_regions();
   {
     G1IsAliveClosure is_alive(this);
     G1KeepAliveClosure keep_alive(this);
@@ -5008,7 +5037,7 @@
   return no_allocs;
 }
 
-void G1CollectedHeap::all_alloc_regions_note_end_of_copying() {
+void G1CollectedHeap::retire_all_alloc_regions() {
   for (int ap = 0; ap < GCAllocPurposeCount; ++ap) {
     HeapRegion* r = _gc_alloc_regions[ap];
     if (r != NULL) {
@@ -5021,8 +5050,7 @@
         }
       }
       if (!has_processed_alias) {
-        r->note_end_of_copying();
-        g1_policy()->record_after_bytes(r->used());
+        retire_alloc_region(r, false /* par */);
       }
     }
   }
--- a/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Thu Feb 05 11:42:10 2009 -0800
+++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Fri Feb 06 01:38:50 2009 +0300
@@ -90,7 +90,7 @@
   HeapRegion* _curr_scan_only;
 
   HeapRegion* _survivor_head;
-  HeapRegion* _survivors_tail;
+  HeapRegion* _survivor_tail;
   size_t      _survivor_length;
 
   void          empty_list(HeapRegion* list);
@@ -105,6 +105,7 @@
   bool          is_empty() { return _length == 0; }
   size_t        length() { return _length; }
   size_t        scan_only_length() { return _scan_only_length; }
+  size_t        survivor_length() { return _survivor_length; }
 
   void rs_length_sampling_init();
   bool rs_length_sampling_more();
@@ -120,6 +121,7 @@
   HeapRegion* first_region() { return _head; }
   HeapRegion* first_scan_only_region() { return _scan_only_head; }
   HeapRegion* first_survivor_region() { return _survivor_head; }
+  HeapRegion* last_survivor_region() { return _survivor_tail; }
   HeapRegion* par_get_next_scan_only_region() {
     MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag);
     HeapRegion* ret = _curr_scan_only;
@@ -219,7 +221,7 @@
   // The to-space memory regions into which objects are being copied during
   // a GC.
   HeapRegion* _gc_alloc_regions[GCAllocPurposeCount];
-  uint _gc_alloc_region_counts[GCAllocPurposeCount];
+  size_t _gc_alloc_region_counts[GCAllocPurposeCount];
 
   // A list of the regions that have been set to be alloc regions in the
   // current collection.
@@ -281,8 +283,8 @@
   // Returns "true" iff none of the gc alloc regions have any allocations
   // since the last call to "save_marks".
   bool all_alloc_regions_no_allocs_since_save_marks();
-  // Calls "note_end_of_copying on all gc alloc_regions.
-  void all_alloc_regions_note_end_of_copying();
+  // Perform finalization stuff on all allocation regions.
+  void retire_all_alloc_regions();
 
   // The number of regions allocated to hold humongous objects.
   int         _num_humongous_regions;
@@ -351,6 +353,10 @@
   // that parallel threads might be attempting allocations.
   void par_allocate_remaining_space(HeapRegion* r);
 
+  // Retires an allocation region when it is full or at the end of a
+  // GC pause.
+  void  retire_alloc_region(HeapRegion* alloc_region, bool par);
+
   // Helper function for two callbacks below.
   // "full", if true, indicates that the GC is for a System.gc() request,
   // and should collect the entire heap.  If "clear_all_soft_refs" is true,
--- a/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp	Thu Feb 05 11:42:10 2009 -0800
+++ b/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp	Fri Feb 06 01:38:50 2009 +0300
@@ -196,8 +196,13 @@
   _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
                                                  G1YoungSurvRateNumRegionsSummary)),
   _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
-                                              G1YoungSurvRateNumRegionsSummary))
+                                              G1YoungSurvRateNumRegionsSummary)),
   // add here any more surv rate groups
+  _recorded_survivor_regions(0),
+  _recorded_survivor_head(NULL),
+  _recorded_survivor_tail(NULL),
+  _survivors_age_table(true)
+
 {
   _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
   _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
@@ -272,6 +277,15 @@
   _concurrent_mark_cleanup_times_ms->add(0.20);
   _tenuring_threshold = MaxTenuringThreshold;
 
+  if (G1UseSurvivorSpace) {
+    // if G1FixedSurvivorSpaceSize is 0 which means the size is not
+    // fixed, then _max_survivor_regions will be calculated at
+    // calculate_young_list_target_config diring initialization
+    _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
+  } else {
+    _max_survivor_regions = 0;
+  }
+
   initialize_all();
 }
 
@@ -301,6 +315,8 @@
                                   "-XX:+UseConcMarkSweepGC.");
   }
 
+  initialize_gc_policy_counters();
+
   if (G1Gen) {
     _in_young_gc_mode = true;
 
@@ -322,6 +338,12 @@
   }
 }
 
+// Create the jstat counters for the policy.
+void G1CollectorPolicy::initialize_gc_policy_counters()
+{
+  _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 2 + G1Gen);
+}
+
 void G1CollectorPolicy::calculate_young_list_min_length() {
   _young_list_min_length = 0;
 
@@ -352,6 +374,7 @@
     guarantee( so_length < _young_list_target_length, "invariant" );
     _young_list_so_prefix_length = so_length;
   }
+  calculate_survivors_policy();
 }
 
 // This method calculate the optimal scan-only set for a fixed young
@@ -448,6 +471,9 @@
   if (full_young_gcs() && _free_regions_at_end_of_collection > 0) {
     // we are in fully-young mode and there are free regions in the heap
 
+    double survivor_regions_evac_time =
+        predict_survivor_regions_evac_time();
+
     size_t min_so_length = 0;
     size_t max_so_length = 0;
 
@@ -497,9 +523,8 @@
       scanned_cards = predict_non_young_card_num(adj_rs_lengths);
     // calculate this once, so that we don't have to recalculate it in
     // the innermost loop
-    double base_time_ms = predict_base_elapsed_time_ms(pending_cards,
-                                                       scanned_cards);
-
+    double base_time_ms = predict_base_elapsed_time_ms(pending_cards, scanned_cards)
+                          + survivor_regions_evac_time;
     // the result
     size_t final_young_length = 0;
     size_t final_so_length = 0;
@@ -548,14 +573,14 @@
     bool done = false;
     // this is the outermost loop
     while (!done) {
-#if 0
+#ifdef TRACE_CALC_YOUNG_CONFIG
       // leave this in for debugging, just in case
       gclog_or_tty->print_cr("searching between " SIZE_FORMAT " and " SIZE_FORMAT
                              ", incr " SIZE_FORMAT ", pass %s",
                              from_so_length, to_so_length, so_length_incr,
                              (pass == pass_type_coarse) ? "coarse" :
                              (pass == pass_type_fine) ? "fine" : "final");
-#endif // 0
+#endif // TRACE_CALC_YOUNG_CONFIG
 
       size_t so_length = from_so_length;
       size_t init_free_regions =
@@ -651,11 +676,11 @@
           guarantee( so_length_incr == so_coarse_increments, "invariant" );
           guarantee( final_so_length >= min_so_length, "invariant" );
 
-#if 0
+#ifdef TRACE_CALC_YOUNG_CONFIG
           // leave this in for debugging, just in case
           gclog_or_tty->print_cr("  coarse pass: SO length " SIZE_FORMAT,
                                  final_so_length);
-#endif // 0
+#endif // TRACE_CALC_YOUNG_CONFIG
 
           from_so_length =
             (final_so_length - min_so_length > so_coarse_increments) ?
@@ -687,12 +712,12 @@
             // of the optimal
             size_t new_so_length = 950 * final_so_length / 1000;
 
-#if 0
+#ifdef TRACE_CALC_YOUNG_CONFIG
             // leave this in for debugging, just in case
             gclog_or_tty->print_cr("  fine pass: SO length " SIZE_FORMAT
                                    ", setting it to " SIZE_FORMAT,
                                     final_so_length, new_so_length);
-#endif // 0
+#endif // TRACE_CALC_YOUNG_CONFIG
 
             from_so_length = new_so_length;
             to_so_length = new_so_length;
@@ -719,7 +744,8 @@
     }
 
     // we should have at least one region in the target young length
-    _young_list_target_length = MAX2((size_t) 1, final_young_length);
+    _young_list_target_length =
+        MAX2((size_t) 1, final_young_length + _recorded_survivor_regions);
     if (final_so_length >= final_young_length)
       // and we need to ensure that the S-O length is not greater than
       // the target young length (this is being a bit careful)
@@ -734,7 +760,7 @@
     double end_time_sec = os::elapsedTime();
     double elapsed_time_ms = (end_time_sec - start_time_sec) * 1000.0;
 
-#if 0
+#ifdef TRACE_CALC_YOUNG_CONFIG
     // leave this in for debugging, just in case
     gclog_or_tty->print_cr("target = %1.1lf ms, young = " SIZE_FORMAT
                            ", SO = " SIZE_FORMAT ", "
@@ -747,9 +773,9 @@
                            calculations,
                            full_young_gcs() ? "full" : "partial",
                            should_initiate_conc_mark() ? " i-m" : "",
-                           in_marking_window(),
-                           in_marking_window_im());
-#endif // 0
+                           _in_marking_window,
+                           _in_marking_window_im);
+#endif // TRACE_CALC_YOUNG_CONFIG
 
     if (_young_list_target_length < _young_list_min_length) {
       // bummer; this means that, if we do a pause when the optimal
@@ -768,14 +794,14 @@
         // S-O length
         so_length = calculate_optimal_so_length(_young_list_min_length);
 
-#if 0
+#ifdef TRACE_CALC_YOUNG_CONFIG
       // leave this in for debugging, just in case
       gclog_or_tty->print_cr("adjusted target length from "
                              SIZE_FORMAT " to " SIZE_FORMAT
                              ", SO " SIZE_FORMAT,
                              _young_list_target_length, _young_list_min_length,
                              so_length);
-#endif // 0
+#endif // TRACE_CALC_YOUNG_CONFIG
 
       _young_list_target_length =
         MAX2(_young_list_min_length, (size_t)1);
@@ -785,12 +811,12 @@
     // we are in a partially-young mode or we've run out of regions (due
     // to evacuation failure)
 
-#if 0
+#ifdef TRACE_CALC_YOUNG_CONFIG
     // leave this in for debugging, just in case
     gclog_or_tty->print_cr("(partial) setting target to " SIZE_FORMAT
                            ", SO " SIZE_FORMAT,
                            _young_list_min_length, 0);
-#endif // 0
+#endif // TRACE_CALC_YOUNG_CONFIG
 
     // we'll do the pause as soon as possible and with no S-O prefix
     // (see above for the reasons behind the latter)
@@ -884,6 +910,16 @@
   return true;
 }
 
+double G1CollectorPolicy::predict_survivor_regions_evac_time() {
+  double survivor_regions_evac_time = 0.0;
+  for (HeapRegion * r = _recorded_survivor_head;
+       r != NULL && r != _recorded_survivor_tail->get_next_young_region();
+       r = r->get_next_young_region()) {
+    survivor_regions_evac_time += predict_region_elapsed_time_ms(r, true);
+  }
+  return survivor_regions_evac_time;
+}
+
 void G1CollectorPolicy::check_prediction_validity() {
   guarantee( adaptive_young_list_length(), "should not call this otherwise" );
 
@@ -995,11 +1031,15 @@
   _short_lived_surv_rate_group->start_adding_regions();
   // also call this on any additional surv rate groups
 
+  record_survivor_regions(0, NULL, NULL);
+
   _prev_region_num_young   = _region_num_young;
   _prev_region_num_tenured = _region_num_tenured;
 
   _free_regions_at_end_of_collection = _g1->free_regions();
   _scan_only_regions_at_end_of_collection = 0;
+  // Reset survivors SurvRateGroup.
+  _survivor_surv_rate_group->reset();
   calculate_young_list_min_length();
   calculate_young_list_target_config();
  }
@@ -1104,6 +1144,10 @@
   _short_lived_surv_rate_group->record_scan_only_prefix(short_lived_so_length);
   tag_scan_only(short_lived_so_length);
 
+  if (G1UseSurvivorSpace) {
+    _survivors_age_table.clear();
+  }
+
   assert( verify_young_ages(), "region age verification" );
 }
 
@@ -1965,9 +2009,6 @@
   // </NEW PREDICTION>
 
   _target_pause_time_ms = -1.0;
-
-  // TODO: calculate tenuring threshold
-  _tenuring_threshold = MaxTenuringThreshold;
 }
 
 // <NEW PREDICTION>
@@ -2058,7 +2099,7 @@
     guarantee( hr->is_young() && hr->age_in_surv_rate_group() != -1,
                "invariant" );
     int age = hr->age_in_surv_rate_group();
-    double yg_surv_rate = predict_yg_surv_rate(age);
+    double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
     bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
   }
 
@@ -2091,7 +2132,7 @@
   }
 #if PREDICTIONS_VERBOSE
   if (young) {
-    _recorded_young_bytes += hr->asSpace()->used();
+    _recorded_young_bytes += hr->used();
   } else {
     _recorded_marked_bytes += hr->max_live_bytes();
   }
@@ -2119,11 +2160,6 @@
       predict_non_young_card_num(_predicted_rs_lengths);
   _recorded_region_num = _recorded_young_regions + _recorded_non_young_regions;
 
-  _predicted_young_survival_ratio = 0.0;
-  for (int i = 0; i < _recorded_young_regions; ++i)
-    _predicted_young_survival_ratio += predict_yg_surv_rate(i);
-  _predicted_young_survival_ratio /= (double) _recorded_young_regions;
-
   _predicted_scan_only_scan_time_ms =
     predict_scan_only_time_ms(_recorded_scan_only_regions);
   _predicted_rs_update_time_ms =
@@ -2673,8 +2709,11 @@
   assert(in_young_gc_mode(), "should be in young GC mode");
   bool ret;
   size_t young_list_length = _g1->young_list_length();
-
-  if (young_list_length < _young_list_target_length) {
+  size_t young_list_max_length = _young_list_target_length;
+  if (G1FixedEdenSize) {
+    young_list_max_length -= _max_survivor_regions;
+  }
+  if (young_list_length < young_list_max_length) {
     ret = true;
     ++_region_num_young;
   } else {
@@ -2710,17 +2749,39 @@
 }
 
 
-uint G1CollectorPolicy::max_regions(int purpose) {
+size_t G1CollectorPolicy::max_regions(int purpose) {
   switch (purpose) {
     case GCAllocForSurvived:
-      return G1MaxSurvivorRegions;
+      return _max_survivor_regions;
     case GCAllocForTenured:
-      return UINT_MAX;
+      return REGIONS_UNLIMITED;
     default:
-      return UINT_MAX;
+      ShouldNotReachHere();
+      return REGIONS_UNLIMITED;
   };
 }
 
+// Calculates survivor space parameters.
+void G1CollectorPolicy::calculate_survivors_policy()
+{
+  if (!G1UseSurvivorSpace) {
+    return;
+  }
+  if (G1FixedSurvivorSpaceSize == 0) {
+    _max_survivor_regions = _young_list_target_length / SurvivorRatio;
+  } else {
+    _max_survivor_regions = G1FixedSurvivorSpaceSize;
+  }
+
+  if (G1FixedTenuringThreshold) {
+    _tenuring_threshold = MaxTenuringThreshold;
+  } else {
+    _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
+        HeapRegion::GrainWords * _max_survivor_regions);
+  }
+}
+
+
 void
 G1CollectorPolicy_BestRegionsFirst::
 set_single_region_collection_set(HeapRegion* hr) {
@@ -2743,7 +2804,11 @@
   double max_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
 
   size_t young_list_length = _g1->young_list_length();
-  bool reached_target_length = young_list_length >= _young_list_target_length;
+  size_t young_list_max_length = _young_list_target_length;
+  if (G1FixedEdenSize) {
+    young_list_max_length -= _max_survivor_regions;
+  }
+  bool reached_target_length = young_list_length >= young_list_max_length;
 
   if (in_young_gc_mode()) {
     if (reached_target_length) {
--- a/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp	Thu Feb 05 11:42:10 2009 -0800
+++ b/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp	Fri Feb 06 01:38:50 2009 +0300
@@ -557,6 +557,8 @@
     return get_new_neg_prediction(_young_gc_eff_seq);
   }
 
+  double predict_survivor_regions_evac_time();
+
   // </NEW PREDICTION>
 
 public:
@@ -599,8 +601,8 @@
 
   // Returns an estimate of the survival rate of the region at yg-age
   // "yg_age".
-  double predict_yg_surv_rate(int age) {
-    TruncatedSeq* seq = _short_lived_surv_rate_group->get_seq(age);
+  double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) {
+    TruncatedSeq* seq = surv_rate_group->get_seq(age);
     if (seq->num() == 0)
       gclog_or_tty->print("BARF! age is %d", age);
     guarantee( seq->num() > 0, "invariant" );
@@ -610,6 +612,10 @@
     return pred;
   }
 
+  double predict_yg_surv_rate(int age) {
+    return predict_yg_surv_rate(age, _short_lived_surv_rate_group);
+  }
+
   double accum_yg_surv_rate_pred(int age) {
     return _short_lived_surv_rate_group->accum_surv_rate_pred(age);
   }
@@ -822,6 +828,9 @@
 
   virtual void init();
 
+  // Create jstat counters for the policy.
+  virtual void initialize_gc_policy_counters();
+
   virtual HeapWord* mem_allocate_work(size_t size,
                                       bool is_tlab,
                                       bool* gc_overhead_limit_was_exceeded);
@@ -1047,8 +1056,12 @@
   // Print stats on young survival ratio
   void print_yg_surv_rate_info() const;
 
-  void finished_recalculating_age_indexes() {
-    _short_lived_surv_rate_group->finished_recalculating_age_indexes();
+  void finished_recalculating_age_indexes(bool is_survivors) {
+    if (is_survivors) {
+      _survivor_surv_rate_group->finished_recalculating_age_indexes();
+    } else {
+      _short_lived_surv_rate_group->finished_recalculating_age_indexes();
+    }
     // do that for any other surv rate groups
   }
 
@@ -1097,6 +1110,17 @@
   // maximum amount of suvivors regions.
   int _tenuring_threshold;
 
+  // The limit on the number of regions allocated for survivors.
+  size_t _max_survivor_regions;
+
+  // The amount of survor regions after a collection.
+  size_t _recorded_survivor_regions;
+  // List of survivor regions.
+  HeapRegion* _recorded_survivor_head;
+  HeapRegion* _recorded_survivor_tail;
+
+  ageTable _survivors_age_table;
+
 public:
 
   inline GCAllocPurpose
@@ -1116,7 +1140,9 @@
     return GCAllocForTenured;
   }
 
-  uint max_regions(int purpose);
+  static const size_t REGIONS_UNLIMITED = ~(size_t)0;
+
+  size_t max_regions(int purpose);
 
   // The limit on regions for a particular purpose is reached.
   void note_alloc_region_limit_reached(int purpose) {
@@ -1132,6 +1158,23 @@
   void note_stop_adding_survivor_regions() {
     _survivor_surv_rate_group->stop_adding_regions();
   }
+
+  void record_survivor_regions(size_t      regions,
+                               HeapRegion* head,
+                               HeapRegion* tail) {
+    _recorded_survivor_regions = regions;
+    _recorded_survivor_head    = head;
+    _recorded_survivor_tail    = tail;
+  }
+
+  void record_thread_age_table(ageTable* age_table)
+  {
+    _survivors_age_table.merge_par(age_table);
+  }
+
+  // Calculates survivor space parameters.
+  void calculate_survivors_policy();
+
 };
 
 // This encapsulates a particular strategy for a g1 Collector.
--- a/src/share/vm/gc_implementation/g1/g1RemSet.cpp	Thu Feb 05 11:42:10 2009 -0800
+++ b/src/share/vm/gc_implementation/g1/g1RemSet.cpp	Fri Feb 06 01:38:50 2009 +0300
@@ -572,6 +572,9 @@
   }
   guarantee( _cards_scanned == NULL, "invariant" );
   _cards_scanned = NEW_C_HEAP_ARRAY(size_t, n_workers());
+  for (uint i = 0; i < n_workers(); ++i) {
+    _cards_scanned[i] = 0;
+  }
   _total_cards_scanned = 0;
 }
 
--- a/src/share/vm/gc_implementation/g1/g1_globals.hpp	Thu Feb 05 11:42:10 2009 -0800
+++ b/src/share/vm/gc_implementation/g1/g1_globals.hpp	Fri Feb 06 01:38:50 2009 +0300
@@ -281,7 +281,17 @@
   develop(bool, G1HRRSFlushLogBuffersOnVerify, false,                       \
           "Forces flushing of log buffers before verification.")            \
                                                                             \
-  product(intx, G1MaxSurvivorRegions, 0,                                    \
-          "The maximum number of survivor regions")
+  product(bool, G1UseSurvivorSpace, true,                                   \
+          "When true, use survivor space.")                                 \
+                                                                            \
+  product(bool, G1FixedTenuringThreshold, false,                            \
+          "When set, G1 will not adjust the tenuring threshold")            \
+                                                                            \
+  product(bool, G1FixedEdenSize, false,                                     \
+          "When set, G1 will not allocate unused survivor space regions")   \
+                                                                            \
+  product(uintx, G1FixedSurvivorSpaceSize, 0,                               \
+          "If non-0 is the size of the G1 survivor space, "                 \
+          "otherwise SurvivorRatio is used to determine the size")
 
 G1_FLAGS(DECLARE_DEVELOPER_FLAG, DECLARE_PD_DEVELOPER_FLAG, DECLARE_PRODUCT_FLAG, DECLARE_PD_PRODUCT_FLAG, DECLARE_DIAGNOSTIC_FLAG, DECLARE_EXPERIMENTAL_FLAG, DECLARE_NOTPRODUCT_FLAG, DECLARE_MANAGEABLE_FLAG, DECLARE_PRODUCT_RW_FLAG)
--- a/src/share/vm/gc_implementation/g1/heapRegion.hpp	Thu Feb 05 11:42:10 2009 -0800
+++ b/src/share/vm/gc_implementation/g1/heapRegion.hpp	Fri Feb 06 01:38:50 2009 +0300
@@ -566,7 +566,11 @@
   void note_end_of_copying() {
     assert(top() >= _next_top_at_mark_start,
            "Increase only");
-    _next_top_at_mark_start = top();
+    // Survivor regions will be scanned on the start of concurrent
+    // marking.
+    if (!is_survivor()) {
+      _next_top_at_mark_start = top();
+    }
   }
 
   // Returns "false" iff no object in the region was allocated when the
--- a/src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp	Thu Feb 05 11:42:10 2009 -0800
+++ b/src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp	Fri Feb 06 01:38:50 2009 +0300
@@ -65,9 +65,11 @@
   // We need access in order to union things into the base table.
   BitMap* bm() { return &_bm; }
 
+#if PRT_COUNT_OCCUPIED
   void recount_occupied() {
     _occupied = (jint) bm()->count_one_bits();
   }
+#endif
 
   PerRegionTable(HeapRegion* hr) :
     _hr(hr),
@@ -1144,7 +1146,9 @@
   size_t i = _outgoing_region_map.get_next_one_offset(0);
   while (i < _outgoing_region_map.size()) {
     HeapRegion* to_region = g1h->region_at(i);
-    to_region->rem_set()->clear_incoming_entry(hr());
+    if (!to_region->in_collection_set()) {
+      to_region->rem_set()->clear_incoming_entry(hr());
+    }
     i = _outgoing_region_map.get_next_one_offset(i+1);
   }
 }
--- a/src/share/vm/gc_implementation/g1/survRateGroup.cpp	Thu Feb 05 11:42:10 2009 -0800
+++ b/src/share/vm/gc_implementation/g1/survRateGroup.cpp	Fri Feb 06 01:38:50 2009 +0300
@@ -29,23 +29,14 @@
                              const char* name,
                              size_t summary_surv_rates_len) :
     _g1p(g1p), _name(name),
-    _all_regions_allocated(0),
-    _curr_length(0), _scan_only_prefix(0), _setup_seq_num(0),
-    _array_length(0), _surv_rate(NULL), _accum_surv_rate_pred(NULL),
-    _accum_surv_rate(0.0), _surv_rate_pred(NULL), _last_pred(0.0),
     _summary_surv_rates_len(summary_surv_rates_len),
     _summary_surv_rates_max_len(0),
-    _summary_surv_rates(NULL) {
-
-  // the following will set up the arrays with length 1
-  _curr_length = 1;
-  stop_adding_regions();
-  guarantee( _array_length == 1, "invariant" );
-  guarantee( _surv_rate_pred[0] != NULL, "invariant" );
-  _surv_rate_pred[0]->add(0.4);
-  all_surviving_words_recorded(false);
-  _curr_length = 0;
-
+    _summary_surv_rates(NULL),
+    _surv_rate(NULL),
+    _accum_surv_rate_pred(NULL),
+    _surv_rate_pred(NULL)
+{
+  reset();
   if (summary_surv_rates_len > 0) {
     size_t length = summary_surv_rates_len;
       _summary_surv_rates = NEW_C_HEAP_ARRAY(NumberSeq*, length);
@@ -60,61 +51,80 @@
   start_adding_regions();
 }
 
+
+void SurvRateGroup::reset()
+{
+  _all_regions_allocated = 0;
+  _scan_only_prefix      = 0;
+  _setup_seq_num         = 0;
+  _stats_arrays_length   = 0;
+  _accum_surv_rate       = 0.0;
+  _last_pred             = 0.0;
+  // the following will set up the arrays with length 1
+  _region_num            = 1;
+  stop_adding_regions();
+  guarantee( _stats_arrays_length == 1, "invariant" );
+  guarantee( _surv_rate_pred[0] != NULL, "invariant" );
+  _surv_rate_pred[0]->add(0.4);
+  all_surviving_words_recorded(false);
+  _region_num = 0;
+}
+
+
 void
 SurvRateGroup::start_adding_regions() {
-  _setup_seq_num   = _array_length;
-  _curr_length     = _scan_only_prefix;
+  _setup_seq_num   = _stats_arrays_length;
+  _region_num      = _scan_only_prefix;
   _accum_surv_rate = 0.0;
 
 #if 0
-  gclog_or_tty->print_cr("start adding regions, seq num %d, length %d",
-                         _setup_seq_num, _curr_length);
+  gclog_or_tty->print_cr("[%s] start adding regions, seq num %d, length %d",
+                         _name, _setup_seq_num, _region_num);
 #endif // 0
 }
 
 void
 SurvRateGroup::stop_adding_regions() {
-  size_t length = _curr_length;
 
 #if 0
-  gclog_or_tty->print_cr("stop adding regions, length %d", length);
+  gclog_or_tty->print_cr("[%s] stop adding regions, length %d", _name, _region_num);
 #endif // 0
 
-  if (length > _array_length) {
+  if (_region_num > _stats_arrays_length) {
     double* old_surv_rate = _surv_rate;
     double* old_accum_surv_rate_pred = _accum_surv_rate_pred;
     TruncatedSeq** old_surv_rate_pred = _surv_rate_pred;
 
-    _surv_rate = NEW_C_HEAP_ARRAY(double, length);
+    _surv_rate = NEW_C_HEAP_ARRAY(double, _region_num);
     if (_surv_rate == NULL) {
-      vm_exit_out_of_memory(sizeof(double) * length,
+      vm_exit_out_of_memory(sizeof(double) * _region_num,
                             "Not enough space for surv rate array.");
     }
-    _accum_surv_rate_pred = NEW_C_HEAP_ARRAY(double, length);
+    _accum_surv_rate_pred = NEW_C_HEAP_ARRAY(double, _region_num);
     if (_accum_surv_rate_pred == NULL) {
-      vm_exit_out_of_memory(sizeof(double) * length,
+      vm_exit_out_of_memory(sizeof(double) * _region_num,
                          "Not enough space for accum surv rate pred array.");
     }
-    _surv_rate_pred = NEW_C_HEAP_ARRAY(TruncatedSeq*, length);
+    _surv_rate_pred = NEW_C_HEAP_ARRAY(TruncatedSeq*, _region_num);
     if (_surv_rate == NULL) {
-      vm_exit_out_of_memory(sizeof(TruncatedSeq*) * length,
+      vm_exit_out_of_memory(sizeof(TruncatedSeq*) * _region_num,
                             "Not enough space for surv rate pred array.");
     }
 
-    for (size_t i = 0; i < _array_length; ++i)
+    for (size_t i = 0; i < _stats_arrays_length; ++i)
       _surv_rate_pred[i] = old_surv_rate_pred[i];
 
 #if 0
-    gclog_or_tty->print_cr("stop adding regions, new seqs %d to %d",
-                  _array_length, length - 1);
+    gclog_or_tty->print_cr("[%s] stop adding regions, new seqs %d to %d",
+                  _name, _array_length, _region_num - 1);
 #endif // 0
 
-    for (size_t i = _array_length; i < length; ++i) {
+    for (size_t i = _stats_arrays_length; i < _region_num; ++i) {
       _surv_rate_pred[i] = new TruncatedSeq(10);
       // _surv_rate_pred[i]->add(last_pred);
     }
 
-    _array_length = length;
+    _stats_arrays_length = _region_num;
 
     if (old_surv_rate != NULL)
       FREE_C_HEAP_ARRAY(double, old_surv_rate);
@@ -124,7 +134,7 @@
       FREE_C_HEAP_ARRAY(NumberSeq*, old_surv_rate_pred);
   }
 
-  for (size_t i = 0; i < _array_length; ++i)
+  for (size_t i = 0; i < _stats_arrays_length; ++i)
     _surv_rate[i] = 0.0;
 }
 
@@ -135,7 +145,7 @@
 
   double ret = _accum_surv_rate;
   if (adjustment > 0) {
-    TruncatedSeq* seq = get_seq(_curr_length+1);
+    TruncatedSeq* seq = get_seq(_region_num+1);
     double surv_rate = _g1p->get_new_prediction(seq);
     ret += surv_rate;
   }
@@ -145,23 +155,23 @@
 
 int
 SurvRateGroup::next_age_index() {
-  TruncatedSeq* seq = get_seq(_curr_length);
+  TruncatedSeq* seq = get_seq(_region_num);
   double surv_rate = _g1p->get_new_prediction(seq);
   _accum_surv_rate += surv_rate;
 
-  ++_curr_length;
+  ++_region_num;
   return (int) ++_all_regions_allocated;
 }
 
 void
 SurvRateGroup::record_scan_only_prefix(size_t scan_only_prefix) {
-  guarantee( scan_only_prefix <= _curr_length, "pre-condition" );
+  guarantee( scan_only_prefix <= _region_num, "pre-condition" );
   _scan_only_prefix = scan_only_prefix;
 }
 
 void
 SurvRateGroup::record_surviving_words(int age_in_group, size_t surv_words) {
-  guarantee( 0 <= age_in_group && (size_t) age_in_group < _curr_length,
+  guarantee( 0 <= age_in_group && (size_t) age_in_group < _region_num,
              "pre-condition" );
   guarantee( _surv_rate[age_in_group] <= 0.00001,
              "should only update each slot once" );
@@ -178,15 +188,15 @@
 
 void
 SurvRateGroup::all_surviving_words_recorded(bool propagate) {
-  if (propagate && _curr_length > 0) { // conservative
-    double surv_rate = _surv_rate_pred[_curr_length-1]->last();
+  if (propagate && _region_num > 0) { // conservative
+    double surv_rate = _surv_rate_pred[_region_num-1]->last();
 
 #if 0
     gclog_or_tty->print_cr("propagating %1.2lf from %d to %d",
                   surv_rate, _curr_length, _array_length - 1);
 #endif // 0
 
-    for (size_t i = _curr_length; i < _array_length; ++i) {
+    for (size_t i = _region_num; i < _stats_arrays_length; ++i) {
       guarantee( _surv_rate[i] <= 0.00001,
                  "the slot should not have been updated" );
       _surv_rate_pred[i]->add(surv_rate);
@@ -195,7 +205,7 @@
 
   double accum = 0.0;
   double pred = 0.0;
-  for (size_t i = 0; i < _array_length; ++i) {
+  for (size_t i = 0; i < _stats_arrays_length; ++i) {
     pred = _g1p->get_new_prediction(_surv_rate_pred[i]);
     if (pred > 1.0) pred = 1.0;
     accum += pred;
@@ -209,8 +219,8 @@
 void
 SurvRateGroup::print() {
   gclog_or_tty->print_cr("Surv Rate Group: %s (%d entries, %d scan-only)",
-                _name, _curr_length, _scan_only_prefix);
-  for (size_t i = 0; i < _curr_length; ++i) {
+                _name, _region_num, _scan_only_prefix);
+  for (size_t i = 0; i < _region_num; ++i) {
     gclog_or_tty->print_cr("    age %4d   surv rate %6.2lf %%   pred %6.2lf %%%s",
                   i, _surv_rate[i] * 100.0,
                   _g1p->get_new_prediction(_surv_rate_pred[i]) * 100.0,
--- a/src/share/vm/gc_implementation/g1/survRateGroup.hpp	Thu Feb 05 11:42:10 2009 -0800
+++ b/src/share/vm/gc_implementation/g1/survRateGroup.hpp	Fri Feb 06 01:38:50 2009 +0300
@@ -29,7 +29,7 @@
   G1CollectorPolicy* _g1p;
   const char* _name;
 
-  size_t  _array_length;
+  size_t  _stats_arrays_length;
   double* _surv_rate;
   double* _accum_surv_rate_pred;
   double  _last_pred;
@@ -40,7 +40,7 @@
   size_t         _summary_surv_rates_max_len;
 
   int _all_regions_allocated;
-  size_t _curr_length;
+  size_t _region_num;
   size_t _scan_only_prefix;
   size_t _setup_seq_num;
 
@@ -48,6 +48,7 @@
   SurvRateGroup(G1CollectorPolicy* g1p,
                 const char* name,
                 size_t summary_surv_rates_len);
+  void reset();
   void start_adding_regions();
   void stop_adding_regions();
   void record_scan_only_prefix(size_t scan_only_prefix);
@@ -55,22 +56,21 @@
   void all_surviving_words_recorded(bool propagate);
   const char* name() { return _name; }
 
-  size_t region_num() { return _curr_length; }
+  size_t region_num() { return _region_num; }
   size_t scan_only_length() { return _scan_only_prefix; }
   double accum_surv_rate_pred(int age) {
     assert(age >= 0, "must be");
-    if ((size_t)age < _array_length)
+    if ((size_t)age < _stats_arrays_length)
       return _accum_surv_rate_pred[age];
     else {
-      double diff = (double) (age - _array_length + 1);
-      return _accum_surv_rate_pred[_array_length-1] + diff * _last_pred;
+      double diff = (double) (age - _stats_arrays_length + 1);
+      return _accum_surv_rate_pred[_stats_arrays_length-1] + diff * _last_pred;
     }
   }
 
   double accum_surv_rate(size_t adjustment);
 
   TruncatedSeq* get_seq(size_t age) {
-    guarantee( 0 <= age, "pre-condition" );
     if (age >= _setup_seq_num) {
       guarantee( _setup_seq_num > 0, "invariant" );
       age = _setup_seq_num-1;
--- a/src/share/vm/gc_implementation/includeDB_gc_g1	Thu Feb 05 11:42:10 2009 -0800
+++ b/src/share/vm/gc_implementation/includeDB_gc_g1	Fri Feb 06 01:38:50 2009 +0300
@@ -172,6 +172,7 @@
 g1CollectorPolicy.cpp                   g1CollectorPolicy.hpp
 g1CollectorPolicy.cpp                   heapRegionRemSet.hpp
 g1CollectorPolicy.cpp			mutexLocker.hpp
+g1CollectorPolicy.cpp			gcPolicyCounters.hpp
 
 g1CollectorPolicy.hpp                   collectorPolicy.hpp
 g1CollectorPolicy.hpp                   collectionSetChooser.hpp
@@ -272,6 +273,7 @@
 heapRegion.hpp                          watermark.hpp
 heapRegion.hpp				g1_specialized_oop_closures.hpp
 heapRegion.hpp				survRateGroup.hpp
+heapRegion.hpp				ageTable.hpp
 
 heapRegionRemSet.hpp			sparsePRT.hpp
 
--- a/src/share/vm/gc_implementation/shared/ageTable.cpp	Thu Feb 05 11:42:10 2009 -0800
+++ b/src/share/vm/gc_implementation/shared/ageTable.cpp	Fri Feb 06 01:38:50 2009 +0300
@@ -67,6 +67,12 @@
   }
 }
 
+void ageTable::merge_par(ageTable* subTable) {
+  for (int i = 0; i < table_size; i++) {
+    Atomic::add_ptr(subTable->sizes[i], &sizes[i]);
+  }
+}
+
 int ageTable::compute_tenuring_threshold(size_t survivor_capacity) {
   size_t desired_survivor_size = (size_t)((((double) survivor_capacity)*TargetSurvivorRatio)/100);
   size_t total = 0;
--- a/src/share/vm/gc_implementation/shared/ageTable.hpp	Thu Feb 05 11:42:10 2009 -0800
+++ b/src/share/vm/gc_implementation/shared/ageTable.hpp	Fri Feb 06 01:38:50 2009 +0300
@@ -56,6 +56,7 @@
   // Merge another age table with the current one.  Used
   // for parallel young generation gc.
   void merge(ageTable* subTable);
+  void merge_par(ageTable* subTable);
 
   // calculate new tenuring threshold based on age information
   int compute_tenuring_threshold(size_t survivor_capacity);