--- a/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Thu Mar 19 08:55:50 2015 -0400
+++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Tue Mar 24 10:04:10 2015 +0000
@@ -3720,7 +3720,7 @@
                                                                   cl.candidate_humongous());
   _has_humongous_reclaim_candidates = cl.candidate_humongous() > 0;
 
-  if (_has_humongous_reclaim_candidates) {
+  if (_has_humongous_reclaim_candidates || G1TraceReclaimDeadHumongousObjectsAtYoungGC) {
     clear_humongous_is_live_table();
   }
 }
@@ -4479,10 +4479,11 @@
 
   if (state == G1CollectedHeap::InCSet) {
     oop forwardee;
-    if (obj->is_forwarded()) {
-      forwardee = obj->forwardee();
+    markOop m = obj->mark();
+    if (m->is_marked()) {
+      forwardee = (oop) m->decode_pointer();
     } else {
-      forwardee = _par_scan_state->copy_to_survivor_space(obj);
+      forwardee = _par_scan_state->copy_to_survivor_space(obj, m);
     }
     assert(forwardee != NULL, "forwardee should not be NULL");
     oopDesc::encode_store_heap_oop(p, forwardee);
@@ -6420,9 +6421,10 @@
         g1h->humongous_region_is_always_live(region_idx)) {
 
       if (G1TraceReclaimDeadHumongousObjectsAtYoungGC) {
-        gclog_or_tty->print_cr("Live humongous %d region %d with remset "SIZE_FORMAT" code roots "SIZE_FORMAT" is marked %d live-other %d obj array %d",
+        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->isHumongous(),
                                region_idx,
+                               obj->size()*HeapWordSize,
                                r->rem_set()->occupied(),
                                r->rem_set()->strong_code_roots_list_length(),
                                next_bitmap->isMarked(r->bottom()),
@@ -6439,8 +6441,9 @@
                       r->bottom()));
 
     if (G1TraceReclaimDeadHumongousObjectsAtYoungGC) {
-      gclog_or_tty->print_cr("Reclaim humongous region %d 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",
+      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 ",
                              r->isHumongous(),
+                             obj->size()*HeapWordSize,
                              r->bottom(),
                              region_idx,
                              r->region_num(),
@@ -6479,7 +6482,8 @@
 void G1CollectedHeap::eagerly_reclaim_humongous_regions() {
   assert_at_safepoint(true);
 
-  if (!G1ReclaimDeadHumongousObjectsAtYoungGC || !_has_humongous_reclaim_candidates) {
+  if (!G1ReclaimDeadHumongousObjectsAtYoungGC ||
+      (!_has_humongous_reclaim_candidates && !G1TraceReclaimDeadHumongousObjectsAtYoungGC)) {
     g1_policy()->phase_times()->record_fast_reclaim_humongous_time_ms(0.0, 0);
     return;
   }

--- a/src/share/vm/gc_implementation/g1/g1ParScanThreadState.cpp	Thu Mar 19 08:55:50 2015 -0400
+++ b/src/share/vm/gc_implementation/g1/g1ParScanThreadState.cpp	Tue Mar 24 10:04:10 2015 +0000
@@ -150,7 +150,8 @@
   } while (!_refs->is_empty());
 }
 
-oop G1ParScanThreadState::copy_to_survivor_space(oop const old) {
+oop G1ParScanThreadState::copy_to_survivor_space(oop const old,
+                                                 markOop const old_mark) {
   size_t word_sz = old->size();
   HeapRegion* from_region = _g1h->heap_region_containing_raw(old);
   // +1 to make the -1 indexes valid...
@@ -158,9 +159,8 @@
   assert( (from_region->is_young() && young_index >  0) ||
          (!from_region->is_young() && young_index == 0), "invariant" );
   G1CollectorPolicy* g1p = _g1h->g1_policy();
-  markOop m = old->mark();
-  int age = m->has_displaced_mark_helper() ? m->displaced_mark_helper()->age()
-                                           : m->age();
+  uint age = old_mark->has_displaced_mark_helper() ? old_mark->displaced_mark_helper()->age()
+                                                   : old_mark->age();
   GCAllocPurpose alloc_purpose = g1p->evacuation_destination(from_region, age,
                                                              word_sz);
   AllocationContext_t context = from_region->allocation_context();
@@ -196,30 +196,22 @@
     alloc_purpose = to_region->is_young() ? GCAllocForSurvived : GCAllocForTenured;
 
     if (g1p->track_object_age(alloc_purpose)) {
-      // We could simply do obj->incr_age(). However, this causes a
-      // performance issue. obj->incr_age() will first check whether
-      // the object has a displaced mark by checking its mark word;
-      // getting the mark word from the new location of the object
-      // stalls. So, given that we already have the mark word and we
-      // are about to install it anyway, it's better to increase the
-      // age on the mark word, when the object does not have a
-      // displaced mark word. We're not expecting many objects to have
-      // a displaced marked word, so that case is not optimized
-      // further (it could be...) and we simply call obj->incr_age().
-
-      if (m->has_displaced_mark_helper()) {
-        // in this case, we have to install the mark word first,
+      if (age < markOopDesc::max_age) {
+        age++;
+      }
+      if (old_mark->has_displaced_mark_helper()) {
+        // In this case, we have to install the mark word first,
         // otherwise obj looks to be forwarded (the old mark word,
         // which contains the forward pointer, was copied)
-        obj->set_mark(m);
-        obj->incr_age();
+        obj->set_mark(old_mark);
+        markOop new_mark = old_mark->displaced_mark_helper()->set_age(age);
+        old_mark->set_displaced_mark_helper(new_mark);
       } else {
-        m = m->incr_age();
-        obj->set_mark(m);
+        obj->set_mark(old_mark->set_age(age));
       }
-      age_table()->add(obj, word_sz);
+      age_table()->add(age, word_sz);
     } else {
-      obj->set_mark(m);
+      obj->set_mark(old_mark);
     }
 
     if (G1StringDedup::is_enabled()) {

--- a/src/share/vm/gc_implementation/g1/g1ParScanThreadState.hpp	Thu Mar 19 08:55:50 2015 -0400
+++ b/src/share/vm/gc_implementation/g1/g1ParScanThreadState.hpp	Tue Mar 24 10:04:10 2015 +0000
@@ -195,7 +195,7 @@
   inline void dispatch_reference(StarTask ref);
  public:
 
-  oop copy_to_survivor_space(oop const obj);
+  oop copy_to_survivor_space(oop const obj, markOop const old_mark);
 
   void trim_queue();
 

--- a/src/share/vm/gc_implementation/g1/g1ParScanThreadState.inline.hpp	Thu Mar 19 08:55:50 2015 -0400
+++ b/src/share/vm/gc_implementation/g1/g1ParScanThreadState.inline.hpp	Tue Mar 24 10:04:10 2015 +0000
@@ -41,10 +41,11 @@
   G1CollectedHeap::in_cset_state_t in_cset_state = _g1h->in_cset_state(obj);
   if (in_cset_state == G1CollectedHeap::InCSet) {
     oop forwardee;
-    if (obj->is_forwarded()) {
-      forwardee = obj->forwardee();
+    markOop m = obj->mark();
+    if (m->is_marked()) {
+      forwardee = (oop) m->decode_pointer();
     } else {
-      forwardee = copy_to_survivor_space(obj);
+      forwardee = copy_to_survivor_space(obj, m);
     }
     oopDesc::encode_store_heap_oop(p, forwardee);
   } else if (in_cset_state == G1CollectedHeap::IsHumongous) {

--- a/src/share/vm/gc_implementation/shared/ageTable.hpp	Thu Mar 19 08:55:50 2015 -0400
+++ b/src/share/vm/gc_implementation/shared/ageTable.hpp	Tue Mar 24 10:04:10 2015 +0000
@@ -55,7 +55,10 @@
 
   // add entry
   void add(oop p, size_t oop_size) {
-    uint age = p->age();
+    add(p->age(), oop_size);
+  }
+
+  void add(uint age, size_t oop_size) {
     assert(age > 0 && age < table_size, "invalid age of object");
     sizes[age] += oop_size;
   }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/gc/g1/TestG1TraceReclaimDeadHumongousObjectsAtYoungGC.java	Tue Mar 24 10:04:10 2015 +0000
@@ -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 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");
+    }
+  }
+}