--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Wed Jan 07 10:19:00 2015 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Wed Jan 07 15:15:37 2015 +0100
@@ -2068,7 +2068,7 @@
 }
 
 void G1CollectedHeap::clear_humongous_is_live_table() {
-  guarantee(G1ReclaimDeadHumongousObjectsAtYoungGC, "Should only be called if true");
+  guarantee(G1EagerReclaimHumongousObjects, "Should only be called if true");
   _humongous_is_live.clear();
 }
 
@@ -3485,8 +3485,24 @@
  private:
   size_t _total_humongous;
   size_t _candidate_humongous;
+
+  DirtyCardQueue _dcq;
+
+  bool humongous_region_is_candidate(uint index) {
+    HeapRegion* region = G1CollectedHeap::heap()->region_at(index);
+    assert(region->is_starts_humongous(), "Must start a humongous object");
+    HeapRegionRemSet* const rset = region->rem_set();
+    bool const allow_stale_refs = G1EagerReclaimHumongousObjectsWithStaleRefs;
+    return !oop(region->bottom())->is_objArray() &&
+           ((allow_stale_refs && rset->occupancy_less_or_equal_than(G1RSetSparseRegionEntries)) ||
+            (!allow_stale_refs && rset->is_empty()));
+  }
+
  public:
-  RegisterHumongousWithInCSetFastTestClosure() : _total_humongous(0), _candidate_humongous(0) {
+  RegisterHumongousWithInCSetFastTestClosure()
+  : _total_humongous(0),
+    _candidate_humongous(0),
+    _dcq(&JavaThread::dirty_card_queue_set()) {
   }
 
   virtual bool doHeapRegion(HeapRegion* r) {
@@ -3496,11 +3512,29 @@
     G1CollectedHeap* g1h = G1CollectedHeap::heap();
 
     uint region_idx = r->hrm_index();
-    bool is_candidate = !g1h->humongous_region_is_always_live(region_idx);
-    // Is_candidate already filters out humongous regions with some remembered set.
-    // This will not lead to humongous object that we mistakenly keep alive because
-    // during young collection the remembered sets will only be added to.
+    bool is_candidate = humongous_region_is_candidate(region_idx);
+    // Is_candidate already filters out humongous object with large remembered sets.
+    // If we have a humongous object with a few remembered sets, we simply flush these
+    // remembered set entries into the DCQS. That will result in automatic
+    // re-evaluation of their remembered set entries during the following evacuation
+    // phase.
     if (is_candidate) {
+      if (!r->rem_set()->is_empty()) {
+        guarantee(r->rem_set()->occupancy_less_or_equal_than(G1RSetSparseRegionEntries),
+                  "Found a not-small remembered set here. This is inconsistent with previous assumptions.");
+        G1SATBCardTableLoggingModRefBS* bs = g1h->g1_barrier_set();
+        HeapRegionRemSetIterator hrrs(r->rem_set());
+        size_t card_index;
+        while (hrrs.has_next(card_index)) {
+          jbyte* card_ptr = (jbyte*)bs->byte_for_index(card_index);
+          if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
+            *card_ptr = CardTableModRefBS::dirty_card_val();
+            _dcq.enqueue(card_ptr);
+          }
+        }
+        r->rem_set()->clear_locked();
+      }
+      assert(r->rem_set()->is_empty(), "At this point any humongous candidate remembered set must be empty.");
       g1h->register_humongous_region_with_in_cset_fast_test(region_idx);
       _candidate_humongous++;
     }
@@ -3511,23 +3545,32 @@
 
   size_t total_humongous() const { return _total_humongous; }
   size_t candidate_humongous() const { return _candidate_humongous; }
+
+  void flush_rem_set_entries() { _dcq.flush(); }
 };
 
 void G1CollectedHeap::register_humongous_regions_with_in_cset_fast_test() {
-  if (!G1ReclaimDeadHumongousObjectsAtYoungGC) {
-    g1_policy()->phase_times()->record_fast_reclaim_humongous_stats(0, 0);
+  if (!G1EagerReclaimHumongousObjects) {
+    g1_policy()->phase_times()->record_fast_reclaim_humongous_stats(0.0, 0, 0);
     return;
   }
+  double time = os::elapsed_counter();
 
   RegisterHumongousWithInCSetFastTestClosure cl;
   heap_region_iterate(&cl);
-  g1_policy()->phase_times()->record_fast_reclaim_humongous_stats(cl.total_humongous(),
+
+  time = ((double)(os::elapsed_counter() - time) / os::elapsed_frequency()) * 1000.0;
+  g1_policy()->phase_times()->record_fast_reclaim_humongous_stats(time,
+                                                                  cl.total_humongous(),
                                                                   cl.candidate_humongous());
   _has_humongous_reclaim_candidates = cl.candidate_humongous() > 0;
 
-  if (_has_humongous_reclaim_candidates || G1TraceReclaimDeadHumongousObjectsAtYoungGC) {
+  if (_has_humongous_reclaim_candidates || G1TraceEagerReclaimHumongousObjects) {
     clear_humongous_is_live_table();
   }
+
+  // Finally flush all remembered set entries to re-check into the global DCQS.
+  cl.flush_rem_set_entries();
 }
 
 void
@@ -6140,22 +6183,20 @@
     // are completely up-to-date wrt to references to the humongous object.
     //
     // Other implementation considerations:
-    // - never consider object arrays: while they are a valid target, they have not
-    // been observed to be used as temporary objects.
-    // - they would also pose considerable effort for cleaning up the the remembered
-    // sets.
-    // While this cleanup is not strictly necessary to be done (or done instantly),
-    // given that their occurrence is very low, this saves us this additional
-    // complexity.
+    // - never consider object arrays at this time because they would pose
+    // considerable effort for cleaning up the the remembered sets. This is
+    // required because stale remembered sets might reference locations that
+    // are currently allocated into.
     uint region_idx = r->hrm_index();
     if (g1h->humongous_is_live(region_idx) ||
         g1h->humongous_region_is_always_live(region_idx)) {
 
-      if (G1TraceReclaimDeadHumongousObjectsAtYoungGC) {
-        gclog_or_tty->print_cr("Live humongous %d region %d size "SIZE_FORMAT" with remset "SIZE_FORMAT" code roots "SIZE_FORMAT" is marked %d live-other %d obj array %d",
-                               r->is_humongous(),
+      if (G1TraceEagerReclaimHumongousObjects) {
+        gclog_or_tty->print_cr("Live humongous region %u size "SIZE_FORMAT" start "PTR_FORMAT" length "UINT32_FORMAT" with remset "SIZE_FORMAT" code roots "SIZE_FORMAT" is marked %d live-other %d obj array %d",
                                region_idx,
                                obj->size()*HeapWordSize,
+                               r->bottom(),
+                               r->region_num(),
                                r->rem_set()->occupied(),
                                r->rem_set()->strong_code_roots_list_length(),
                                next_bitmap->isMarked(r->bottom()),
@@ -6171,12 +6212,11 @@
               err_msg("Eagerly reclaiming object arrays is not supported, but the object "PTR_FORMAT" is.",
                       r->bottom()));
 
-    if (G1TraceReclaimDeadHumongousObjectsAtYoungGC) {
-      gclog_or_tty->print_cr("Reclaim humongous region %d size "SIZE_FORMAT" start "PTR_FORMAT" region %d length "UINT32_FORMAT" with remset "SIZE_FORMAT" code roots "SIZE_FORMAT" is marked %d live-other %d obj array %d",
-                             r->is_humongous(),
+    if (G1TraceEagerReclaimHumongousObjects) {
+      gclog_or_tty->print_cr("Dead humongous region %u size "SIZE_FORMAT" start "PTR_FORMAT" length "UINT32_FORMAT" with remset "SIZE_FORMAT" code roots "SIZE_FORMAT" is marked %d live-other %d obj array %d",
+                             region_idx,
                              obj->size()*HeapWordSize,
                              r->bottom(),
-                             region_idx,
                              r->region_num(),
                              r->rem_set()->occupied(),
                              r->rem_set()->strong_code_roots_list_length(),
@@ -6213,8 +6253,8 @@
 void G1CollectedHeap::eagerly_reclaim_humongous_regions() {
   assert_at_safepoint(true);
 
-  if (!G1ReclaimDeadHumongousObjectsAtYoungGC ||
-      (!_has_humongous_reclaim_candidates && !G1TraceReclaimDeadHumongousObjectsAtYoungGC)) {
+  if (!G1EagerReclaimHumongousObjects ||
+      (!_has_humongous_reclaim_candidates && !G1TraceEagerReclaimHumongousObjects)) {
     g1_policy()->phase_times()->record_fast_reclaim_humongous_time_ms(0.0, 0);
     return;
   }

--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Wed Jan 07 10:19:00 2015 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Wed Jan 07 15:15:37 2015 +0100
@@ -641,6 +641,9 @@
   // Returns whether the given region (which must be a humongous (start) region)
   // is to be considered conservatively live regardless of any other conditions.
   bool humongous_region_is_always_live(uint index);
+  // Returns whether the given region (which must be a humongous (start) region)
+  // is considered a candidate for eager reclamation.
+  bool humongous_region_is_candidate(uint index);
   // Register the given region to be part of the collection set.
   inline void register_humongous_region_with_in_cset_fast_test(uint index);
   // Register regions with humongous objects (actually on the start region) in

--- a/hotspot/src/share/vm/gc_implementation/g1/g1GCPhaseTimes.cpp	Wed Jan 07 10:19:00 2015 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1GCPhaseTimes.cpp	Wed Jan 07 15:15:37 2015 +0100
@@ -344,11 +344,14 @@
     _last_redirty_logged_cards_time_ms.print(3, "Parallel Redirty");
     _last_redirty_logged_cards_processed_cards.print(3, "Redirtied Cards");
   }
-  if (G1ReclaimDeadHumongousObjectsAtYoungGC) {
-    print_stats(2, "Humongous Reclaim", _cur_fast_reclaim_humongous_time_ms);
+  if (G1EagerReclaimHumongousObjects) {
+    print_stats(2, "Humongous Register", _cur_fast_reclaim_humongous_register_time_ms);
     if (G1Log::finest()) {
       print_stats(3, "Humongous Total", _cur_fast_reclaim_humongous_total);
       print_stats(3, "Humongous Candidate", _cur_fast_reclaim_humongous_candidates);
+    }
+    print_stats(2, "Humongous Reclaim", _cur_fast_reclaim_humongous_time_ms);
+    if (G1Log::finest()) {
       print_stats(3, "Humongous Reclaimed", _cur_fast_reclaim_humongous_reclaimed);
     }
   }

--- a/hotspot/src/share/vm/gc_implementation/g1/g1GCPhaseTimes.hpp	Wed Jan 07 10:19:00 2015 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1GCPhaseTimes.hpp	Wed Jan 07 15:15:37 2015 +0100
@@ -157,6 +157,7 @@
   double _recorded_non_young_free_cset_time_ms;
 
   double _cur_fast_reclaim_humongous_time_ms;
+  double _cur_fast_reclaim_humongous_register_time_ms;
   size_t _cur_fast_reclaim_humongous_total;
   size_t _cur_fast_reclaim_humongous_candidates;
   size_t _cur_fast_reclaim_humongous_reclaimed;
@@ -283,7 +284,8 @@
     _recorded_non_young_free_cset_time_ms = time_ms;
   }
 
-  void record_fast_reclaim_humongous_stats(size_t total, size_t candidates) {
+  void record_fast_reclaim_humongous_stats(double time_ms, size_t total, size_t candidates) {
+    _cur_fast_reclaim_humongous_register_time_ms = time_ms;
     _cur_fast_reclaim_humongous_total = total;
     _cur_fast_reclaim_humongous_candidates = candidates;
   }

--- a/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp	Wed Jan 07 10:19:00 2015 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp	Wed Jan 07 15:15:37 2015 +0100
@@ -270,10 +270,14 @@
   product(uintx, G1MixedGCCountTarget, 8,                                   \
           "The target number of mixed GCs after a marking cycle.")          \
                                                                             \
-  experimental(bool, G1ReclaimDeadHumongousObjectsAtYoungGC, true,          \
+  experimental(bool, G1EagerReclaimHumongousObjects, true,                  \
           "Try to reclaim dead large objects at every young GC.")           \
                                                                             \
-  experimental(bool, G1TraceReclaimDeadHumongousObjectsAtYoungGC, false,    \
+  experimental(bool, G1EagerReclaimHumongousObjectsWithStaleRefs, true,     \
+          "Try to reclaim dead large objects that have a few stale "        \
+          "references at every young GC.")                                  \
+                                                                            \
+  experimental(bool, G1TraceEagerReclaimHumongousObjects, false,            \
           "Print some information about large object liveness "             \
           "at every young GC.")                                             \
                                                                             \

--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp	Wed Jan 07 10:19:00 2015 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp	Wed Jan 07 15:15:37 2015 +0100
@@ -681,6 +681,18 @@
   clear_fcc();
 }
 
+bool OtherRegionsTable::occupancy_less_or_equal_than(size_t limit) const {
+  if (limit <= (size_t)G1RSetSparseRegionEntries) {
+    return occ_coarse() == 0 && _first_all_fine_prts == NULL && occ_sparse() <= limit;
+  } else {
+    // Current uses of this method may only use values less than G1RSetSparseRegionEntries
+    // for the limit. The solution, comparing against occupied() would be too slow
+    // at this time.
+    Unimplemented();
+    return false;
+  }
+}
+
 bool OtherRegionsTable::is_empty() const {
   return occ_sparse() == 0 && occ_coarse() == 0 && _first_all_fine_prts == NULL;
 }

--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegionRemSet.hpp	Wed Jan 07 10:19:00 2015 +0100
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegionRemSet.hpp	Wed Jan 07 15:15:37 2015 +0100
@@ -183,6 +183,10 @@
   // Returns whether the remembered set contains the given reference.
   bool contains_reference(OopOrNarrowOopStar from) const;
 
+  // Returns whether this remembered set (and all sub-sets) have an occupancy
+  // that is less or equal than the given occupancy.
+  bool occupancy_less_or_equal_than(size_t limit) const;
+
   // Removes any entries shown by the given bitmaps to contain only dead
   // objects. Not thread safe.
   // Set bits in the bitmaps indicate that the given region or card is live.
@@ -261,6 +265,10 @@
     return (strong_code_roots_list_length() == 0) && _other_regions.is_empty();
   }
 
+  bool occupancy_less_or_equal_than(size_t occ) const {
+    return (strong_code_roots_list_length() == 0) && _other_regions.occupancy_less_or_equal_than(occ);
+  }
+
   size_t occupied() {
     MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
     return occupied_locked();

--- a/hotspot/test/gc/g1/TestEagerReclaimHumongousRegions2.java	Wed Jan 07 10:19:00 2015 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,131 +0,0 @@
-/*
- * Copyright (c) 2014, 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
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-/*
- * @test TestEagerReclaimHumongousRegions2
- * @bug 8051973
- * @summary Test to make sure that eager reclaim of humongous objects correctly clears
- * mark bitmaps at reclaim.
- * @key gc
- * @library /testlibrary
- */
-
-import java.util.ArrayList;
-import java.util.LinkedList;
-import java.util.Random;
-
-import com.oracle.java.testlibrary.OutputAnalyzer;
-import com.oracle.java.testlibrary.ProcessTools;
-
-// An object that has a few references to other instances to slow down marking.
-class ObjectWithSomeRefs {
-    public ObjectWithSomeRefs other1;
-    public ObjectWithSomeRefs other2;
-    public ObjectWithSomeRefs other3;
-    public ObjectWithSomeRefs other4;
-}
-
-class ReclaimRegionFast {
-    public static final long MAX_MILLIS_FOR_RUN = 50 * 1000; // The maximum runtime for the actual test.
-
-    public static final int M = 1024*1024;
-
-    public static LinkedList<Object> garbageList = new LinkedList<Object>();
-
-    public static void genGarbage(Object large) {
-        for (int i = 0; i < 64*1024; i++) {
-            Object[] garbage = new Object[50];
-            garbage[0] = large;
-            garbageList.add(garbage);
-        }
-        garbageList.clear();
-    }
-
-    public static ArrayList<ObjectWithSomeRefs> longList = new ArrayList<ObjectWithSomeRefs>();
-
-    public static void main(String[] args) {
-
-        for (int i = 0; i < 16*1024; i++) {
-             longList.add(new ObjectWithSomeRefs());
-        }
-
-        Random rnd = new Random();
-        for (int i = 0; i < longList.size(); i++) {
-             int len = longList.size();
-             longList.get(i).other1 = longList.get(rnd.nextInt(len));
-             longList.get(i).other2 = longList.get(rnd.nextInt(len));
-             longList.get(i).other3 = longList.get(rnd.nextInt(len));
-             longList.get(i).other4 = longList.get(rnd.nextInt(len));
-        }
-
-        int[] large1 = new int[M];
-        int[] large2 = null;
-        int[] large3 = null;
-        int[] large4 = null;
-
-        Object ref_from_stack = large1;
-
-        long start_millis = System.currentTimeMillis();
-
-        for (int i = 0; i < 20; i++) {
-            long current_millis = System.currentTimeMillis();
-            if ((current_millis - start_millis) > MAX_MILLIS_FOR_RUN) {
-              System.out.println("Finishing test because maximum runtime exceeded");
-              break;
-            }
-            // A set of large objects that will be reclaimed eagerly - and hopefully marked.
-            large1 = new int[M - 20];
-            large2 = new int[M - 20];
-            large3 = new int[M - 20];
-            large4 = new int[M - 20];
-            genGarbage(large1);
-            // Make sure that the compiler cannot completely remove
-            // the allocation of the large object until here.
-            System.out.println(large1 + " " + large2 + " " + large3 + " " + large4);
-        }
-
-        // Keep the reference to the first object alive.
-        System.out.println(ref_from_stack);
-    }
-}
-
-public class TestEagerReclaimHumongousRegions2 {
-    public static void main(String[] args) throws Exception {
-        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
-            "-XX:+UseG1GC",
-            "-Xms128M",
-            "-Xmx128M",
-            "-Xmn2M",
-            "-XX:G1HeapRegionSize=1M",
-            "-XX:InitiatingHeapOccupancyPercent=0", // Want to have as much as possible initial marks.
-            "-XX:+PrintGC",
-            "-XX:+VerifyAfterGC",
-            "-XX:ConcGCThreads=1", // Want to make marking as slow as possible.
-            "-XX:+IgnoreUnrecognizedVMOptions", // G1VerifyBitmaps is develop only.
-            "-XX:+G1VerifyBitmaps",
-            ReclaimRegionFast.class.getName());
-        OutputAnalyzer output = new OutputAnalyzer(pb.start());
-        output.shouldHaveExitValue(0);
-    }
-}
-

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/gc/g1/TestEagerReclaimHumongousRegionsClearMarkBits.java	Wed Jan 07 15:15:37 2015 +0100
@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2014, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test TestEagerReclaimHumongousRegionsClearMarkBits
+ * @bug 8051973
+ * @summary Test to make sure that eager reclaim of humongous objects correctly clears
+ * mark bitmaps at reclaim.
+ * @key gc
+ * @library /testlibrary
+ */
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.Random;
+
+import com.oracle.java.testlibrary.OutputAnalyzer;
+import com.oracle.java.testlibrary.ProcessTools;
+
+// An object that has a few references to other instances to slow down marking.
+class ObjectWithSomeRefs {
+    public ObjectWithSomeRefs other1;
+    public ObjectWithSomeRefs other2;
+    public ObjectWithSomeRefs other3;
+    public ObjectWithSomeRefs other4;
+}
+
+class ReclaimRegionFast {
+    public static final long MAX_MILLIS_FOR_RUN = 50 * 1000; // The maximum runtime for the actual test.
+
+    public static final int M = 1024*1024;
+
+    public static LinkedList<Object> garbageList = new LinkedList<Object>();
+
+    public static void genGarbage(Object large) {
+        for (int i = 0; i < 64*1024; i++) {
+            Object[] garbage = new Object[50];
+            garbage[0] = large;
+            garbageList.add(garbage);
+        }
+        garbageList.clear();
+    }
+
+    public static ArrayList<ObjectWithSomeRefs> longList = new ArrayList<ObjectWithSomeRefs>();
+
+    public static void main(String[] args) {
+
+        for (int i = 0; i < 16*1024; i++) {
+             longList.add(new ObjectWithSomeRefs());
+        }
+
+        Random rnd = new Random();
+        for (int i = 0; i < longList.size(); i++) {
+             int len = longList.size();
+             longList.get(i).other1 = longList.get(rnd.nextInt(len));
+             longList.get(i).other2 = longList.get(rnd.nextInt(len));
+             longList.get(i).other3 = longList.get(rnd.nextInt(len));
+             longList.get(i).other4 = longList.get(rnd.nextInt(len));
+        }
+
+        int[] large1 = new int[M];
+        int[] large2 = null;
+        int[] large3 = null;
+        int[] large4 = null;
+
+        Object ref_from_stack = large1;
+
+        long start_millis = System.currentTimeMillis();
+
+        for (int i = 0; i < 20; i++) {
+            long current_millis = System.currentTimeMillis();
+            if ((current_millis - start_millis) > MAX_MILLIS_FOR_RUN) {
+              System.out.println("Finishing test because maximum runtime exceeded");
+              break;
+            }
+            // A set of large objects that will be reclaimed eagerly - and hopefully marked.
+            large1 = new int[M - 20];
+            large2 = new int[M - 20];
+            large3 = new int[M - 20];
+            large4 = new int[M - 20];
+            genGarbage(large1);
+            // Make sure that the compiler cannot completely remove
+            // the allocation of the large object until here.
+            System.out.println(large1 + " " + large2 + " " + large3 + " " + large4);
+        }
+
+        // Keep the reference to the first object alive.
+        System.out.println(ref_from_stack);
+    }
+}
+
+public class TestEagerReclaimHumongousRegionsClearMarkBits {
+    public static void main(String[] args) throws Exception {
+        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
+            "-XX:+UseG1GC",
+            "-Xms128M",
+            "-Xmx128M",
+            "-Xmn2M",
+            "-XX:G1HeapRegionSize=1M",
+            "-XX:InitiatingHeapOccupancyPercent=0", // Want to have as much as possible initial marks.
+            "-XX:+PrintGC",
+            "-XX:+VerifyAfterGC",
+            "-XX:ConcGCThreads=1", // Want to make marking as slow as possible.
+            "-XX:+IgnoreUnrecognizedVMOptions", // G1VerifyBitmaps is develop only.
+            "-XX:+G1VerifyBitmaps",
+            ReclaimRegionFast.class.getName());
+        OutputAnalyzer output = new OutputAnalyzer(pb.start());
+        output.shouldHaveExitValue(0);
+    }
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/gc/g1/TestEagerReclaimHumongousRegionsWithRefs.java	Wed Jan 07 15:15:37 2015 +0100
@@ -0,0 +1,113 @@
+/*
+ * Copyright (c) 2014, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test TestEagerReclaimHumongousRegionsWithRefs
+ * @bug 8048179
+ * @summary Test to make sure that eager reclaim of humongous objects that have previously
+ * been referenced by other old gen regions work. We simply try to fill
+ * up the heap with humongous objects and create a remembered set entry from an object by
+ * referencing that we know is in the old gen. After changing this reference, the object
+ * should still be eagerly reclaimable to avoid Full GC.
+ * @key gc
+ * @library /testlibrary
+ */
+
+import java.util.regex.Pattern;
+import java.util.regex.Matcher;
+import java.util.LinkedList;
+
+import com.oracle.java.testlibrary.OutputAnalyzer;
+import com.oracle.java.testlibrary.ProcessTools;
+import static com.oracle.java.testlibrary.Asserts.*;
+
+class RefHolder {
+  Object ref;
+}
+
+class ReclaimRegionFast {
+
+    public static final int M = 1024*1024;
+
+    public static LinkedList<Object> garbageList = new LinkedList<Object>();
+
+    public static void genGarbage() {
+        for (int i = 0; i < 32*1024; i++) {
+            garbageList.add(new int[100]);
+        }
+        garbageList.clear();
+    }
+
+
+    // A large object referenced by a static.
+    static int[] filler = new int[10 * M];
+
+    // Old gen object referencing the large object, generating remembered
+    // set entries.
+    static RefHolder fromOld = new RefHolder();
+
+    public static void main(String[] args) {
+
+        int[] large = new int[M];
+
+        Object ref_from_stack = large;
+
+        for (int i = 0; i < 100; i++) {
+            // A large object that will be reclaimed eagerly.
+            large = new int[6*M];
+            fromOld.ref = large;
+            genGarbage();
+        }
+
+        // Keep the reference to the first object alive.
+        System.out.println(ref_from_stack);
+    }
+}
+
+public class TestEagerReclaimHumongousRegionsWithRefs {
+
+    public static void main(String[] args) throws Exception {
+        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
+            "-XX:+UseG1GC",
+            "-Xms128M",
+            "-Xmx128M",
+            "-Xmn16M",
+            "-XX:+PrintGC",
+            ReclaimRegionFast.class.getName());
+
+        Pattern p = Pattern.compile("Full GC");
+
+        OutputAnalyzer output = new OutputAnalyzer(pb.start());
+
+        int found = 0;
+        Matcher m = p.matcher(output.getStdout());
+        while (m.find()) {
+            found++;
+        }
+        System.out.println("Issued " + found + " Full GCs");
+
+        assertLessThan(found, 10, "Found that " + found + " Full GCs were issued. This is larger than the bound. Eager reclaim of objects once referenced from old gen seems to not work at all");
+        output.shouldHaveExitValue(0);
+    }
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/gc/g1/TestG1TraceEagerReclaimHumongousObjects.java	Wed Jan 07 15:15:37 2015 +0100
@@ -0,0 +1,142 @@
+/*
+ * Copyright (c) 2014, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test TestG1TraceEagerReclaimHumongousObjects
+ * @bug 8058801 8048179
+ * @summary Ensure that the output for a G1TraceEagerReclaimHumongousObjects
+ * includes the expected necessary messages.
+ * @key gc
+ * @library /testlibrary
+ */
+
+import com.oracle.java.testlibrary.ProcessTools;
+import com.oracle.java.testlibrary.OutputAnalyzer;
+import java.util.LinkedList;
+
+public class TestG1TraceEagerReclaimHumongousObjects {
+  public static void main(String[] args) throws Exception {
+    testGCLogs();
+    testHumongousObjectGCLogs();
+  }
+
+  private static void testGCLogs() throws Exception {
+
+    ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-XX:+UseG1GC",
+                                               "-Xms128M",
+                                               "-Xmx128M",
+                                               "-Xmn16M",
+                                               "-XX:G1HeapRegionSize=1M",
+                                               "-XX:+PrintGC",
+                                               "-XX:+UnlockExperimentalVMOptions",
+                                               "-XX:G1LogLevel=finest",
+                                               "-XX:+G1TraceEagerReclaimHumongousObjects",
+                                               GCTest.class.getName());
+
+    OutputAnalyzer output = new OutputAnalyzer(pb.start());
+
+    // As G1EagerReclaimHumongousObjects is set(default), below logs should be displayed.
+    // And GCTest doesn't have humongous objects, so values should be zero.
+    output.shouldContain("[Humongous Reclaim");
+    output.shouldContain("[Humongous Total: 0]");
+    output.shouldContain("[Humongous Candidate: 0]");
+    output.shouldContain("[Humongous Reclaimed: 0]");
+
+    output.shouldHaveExitValue(0);
+  }
+
+  private static void testHumongousObjectGCLogs() throws Exception {
+    ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-XX:+UseG1GC",
+                                               "-Xms128M",
+                                               "-Xmx128M",
+                                               "-Xmn16M",
+                                               "-XX:G1HeapRegionSize=1M",
+                                               "-XX:+PrintGC",
+                                               "-XX:+UnlockExperimentalVMOptions",
+                                               "-XX:G1LogLevel=finest",
+                                               "-XX:+G1TraceEagerReclaimHumongousObjects",
+                                               GCWithHumongousObjectTest.class.getName());
+
+    OutputAnalyzer output = new OutputAnalyzer(pb.start());
+
+    // As G1ReclaimDeadHumongousObjectsAtYoungGC is set(default), below logs should be displayed.
+    output.shouldContain("[Humongous Reclaim");
+    output.shouldContain("[Humongous Total");
+    output.shouldContain("[Humongous Candidate");
+    output.shouldContain("[Humongous Reclaimed");
+
+    // As G1TraceReclaimDeadHumongousObjectsAtYoungGC is set and GCWithHumongousObjectTest has humongous objects,
+    // these logs should be displayed.
+    output.shouldContain("Live humongous");
+    output.shouldContain("Dead humongous region");
+    output.shouldHaveExitValue(0);
+  }
+
+  static class GCTest {
+    private static byte[] garbage;
+
+    public static void main(String [] args) {
+      System.out.println("Creating garbage");
+      // create 128MB of garbage. This should result in at least one GC
+      for (int i = 0; i < 1024; i++) {
+        garbage = new byte[128 * 1024];
+      }
+      System.out.println("Done");
+    }
+  }
+
+  static class GCWithHumongousObjectTest {
+
+    public static final int M = 1024*1024;
+    public static LinkedList<Object> garbageList = new LinkedList<Object>();
+    // A large object referenced by a static.
+    static int[] filler = new int[10 * M];
+
+    public static void genGarbage() {
+      for (int i = 0; i < 32*1024; i++) {
+        garbageList.add(new int[100]);
+      }
+      garbageList.clear();
+    }
+
+    public static void main(String[] args) {
+
+      int[] large = new int[M];
+      Object ref = large;
+
+      System.out.println("Creating garbage");
+      for (int i = 0; i < 100; i++) {
+        // A large object that will be reclaimed eagerly.
+        large = new int[6*M];
+        genGarbage();
+        // Make sure that the compiler cannot completely remove
+        // the allocation of the large object until here.
+        System.out.println(large);
+      }
+
+      // Keep the reference to the first object alive.
+      System.out.println(ref);
+      System.out.println("Done");
+    }
+  }
+}

--- a/hotspot/test/gc/g1/TestG1TraceReclaimDeadHumongousObjectsAtYoungGC.java	Wed Jan 07 10:19:00 2015 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,142 +0,0 @@
-/*
- * Copyright (c) 2014, 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
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-/*
- * @test TestG1TraceReclaimDeadHumongousObjectsAtYoungGC
- * @bug 8058801
- * @summary Ensure that the output for a G1TraceReclaimDeadHumongousObjectsAtYoungGC
- * includes the expected necessary messages.
- * @key gc
- * @library /testlibrary
- */
-
-import com.oracle.java.testlibrary.ProcessTools;
-import com.oracle.java.testlibrary.OutputAnalyzer;
-import java.util.LinkedList;
-
-public class TestG1TraceReclaimDeadHumongousObjectsAtYoungGC {
-  public static void main(String[] args) throws Exception {
-    testGCLogs();
-    testHumongousObjectGCLogs();
-  }
-
-  private static void testGCLogs() throws Exception {
-
-    ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-XX:+UseG1GC",
-                                               "-Xms128M",
-                                               "-Xmx128M",
-                                               "-Xmn16M",
-                                               "-XX:G1HeapRegionSize=1M",
-                                               "-XX:+PrintGC",
-                                               "-XX:+UnlockExperimentalVMOptions",
-                                               "-XX:G1LogLevel=finest",
-                                               "-XX:+G1TraceReclaimDeadHumongousObjectsAtYoungGC",
-                                               GCTest.class.getName());
-
-    OutputAnalyzer output = new OutputAnalyzer(pb.start());
-
-    // As G1ReclaimDeadHumongousObjectsAtYoungGC is set(default), below logs should be displayed.
-    // And GCTest doesn't have humongous objects, so values should be zero.
-    output.shouldContain("[Humongous Reclaim");
-    output.shouldContain("[Humongous Total: 0]");
-    output.shouldContain("[Humongous Candidate: 0]");
-    output.shouldContain("[Humongous Reclaimed: 0]");
-
-    output.shouldHaveExitValue(0);
-  }
-
-  private static void testHumongousObjectGCLogs() throws Exception {
-    ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-XX:+UseG1GC",
-                                               "-Xms128M",
-                                               "-Xmx128M",
-                                               "-Xmn16M",
-                                               "-XX:G1HeapRegionSize=1M",
-                                               "-XX:+PrintGC",
-                                               "-XX:+UnlockExperimentalVMOptions",
-                                               "-XX:G1LogLevel=finest",
-                                               "-XX:+G1TraceReclaimDeadHumongousObjectsAtYoungGC",
-                                               GCWithHumongousObjectTest.class.getName());
-
-    OutputAnalyzer output = new OutputAnalyzer(pb.start());
-
-    // As G1ReclaimDeadHumongousObjectsAtYoungGC is set(default), below logs should be displayed.
-    output.shouldContain("[Humongous Reclaim");
-    output.shouldContain("[Humongous Total");
-    output.shouldContain("[Humongous Candidate");
-    output.shouldContain("[Humongous Reclaimed");
-
-    // As G1TraceReclaimDeadHumongousObjectsAtYoungGC is set and GCWithHumongousObjectTest has humongous objects,
-    // these logs should be displayed.
-    output.shouldContain("Live humongous");
-    output.shouldContain("Reclaim humongous region");
-    output.shouldHaveExitValue(0);
-  }
-
-  static class GCTest {
-    private static byte[] garbage;
-
-    public static void main(String [] args) {
-      System.out.println("Creating garbage");
-      // create 128MB of garbage. This should result in at least one GC
-      for (int i = 0; i < 1024; i++) {
-        garbage = new byte[128 * 1024];
-      }
-      System.out.println("Done");
-    }
-  }
-
-  static class GCWithHumongousObjectTest {
-
-    public static final int M = 1024*1024;
-    public static LinkedList<Object> garbageList = new LinkedList<Object>();
-    // A large object referenced by a static.
-    static int[] filler = new int[10 * M];
-
-    public static void genGarbage() {
-      for (int i = 0; i < 32*1024; i++) {
-        garbageList.add(new int[100]);
-      }
-      garbageList.clear();
-    }
-
-    public static void main(String[] args) {
-
-      int[] large = new int[M];
-      Object ref = large;
-
-      System.out.println("Creating garbage");
-      for (int i = 0; i < 100; i++) {
-        // A large object that will be reclaimed eagerly.
-        large = new int[6*M];
-        genGarbage();
-        // Make sure that the compiler cannot completely remove
-        // the allocation of the large object until here.
-        System.out.println(large);
-      }
-
-      // Keep the reference to the first object alive.
-      System.out.println(ref);
-      System.out.println("Done");
-    }
-  }
-}

--- a/hotspot/test/gc/g1/TestGCLogMessages.java	Wed Jan 07 10:19:00 2015 +0100
+++ b/hotspot/test/gc/g1/TestGCLogMessages.java	Wed Jan 07 15:15:37 2015 +0100
@@ -23,7 +23,7 @@
 
 /*
  * @test TestGCLogMessages
- * @bug 8035406 8027295 8035398 8019342 8027959
+ * @bug 8035406 8027295 8035398 8019342 8027959 8048179
  * @summary Ensure that the PrintGCDetails output for a minor GC with G1
  * includes the expected necessary messages.
  * @key gc
@@ -54,6 +54,7 @@
     output.shouldNotContain("[String Dedup Fixup");
     output.shouldNotContain("[Young Free CSet");
     output.shouldNotContain("[Non-Young Free CSet");
+    output.shouldNotContain("[Humongous Register");
     output.shouldNotContain("[Humongous Reclaim");
     output.shouldHaveExitValue(0);
 
@@ -72,9 +73,10 @@
     output.shouldContain("[String Dedup Fixup");
     output.shouldNotContain("[Young Free CSet");
     output.shouldNotContain("[Non-Young Free CSet");
-    output.shouldContain("[Humongous Reclaim");
+    output.shouldContain("[Humongous Register");
     output.shouldNotContain("[Humongous Total");
     output.shouldNotContain("[Humongous Candidate");
+    output.shouldContain("[Humongous Reclaim");
     output.shouldNotContain("[Humongous Reclaimed");
     output.shouldHaveExitValue(0);
 
@@ -95,9 +97,10 @@
     output.shouldContain("[String Dedup Fixup");
     output.shouldContain("[Young Free CSet");
     output.shouldContain("[Non-Young Free CSet");
-    output.shouldContain("[Humongous Reclaim");
+    output.shouldContain("[Humongous Register");
     output.shouldContain("[Humongous Total");
     output.shouldContain("[Humongous Candidate");
+    output.shouldContain("[Humongous Reclaim");
     output.shouldContain("[Humongous Reclaimed");
     output.shouldHaveExitValue(0);
   }