diff -r f2e823305677 -r e582172ff6ff hotspot/src/share/vm/gc_implementation/g1/heapRegion.hpp
--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegion.hpp	Tue Jul 17 12:24:05 2012 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegion.hpp	Thu Jul 19 15:15:54 2012 -0700
@@ -55,7 +55,10 @@
 #define HR_FORMAT "%u:(%s)["PTR_FORMAT","PTR_FORMAT","PTR_FORMAT"]"
 #define HR_FORMAT_PARAMS(_hr_) \
                 (_hr_)->hrs_index(), \
-                (_hr_)->is_survivor() ? "S" : (_hr_)->is_young() ? "E" : "-", \
+                (_hr_)->is_survivor() ? "S" : (_hr_)->is_young() ? "E" : \
+                (_hr_)->startsHumongous() ? "HS" : \
+                (_hr_)->continuesHumongous() ? "HC" : \
+                !(_hr_)->is_empty() ? "O" : "F", \
                 (_hr_)->bottom(), (_hr_)->top(), (_hr_)->end()
 
 // sentinel value for hrs_index
@@ -173,6 +176,7 @@
   virtual HeapWord* saved_mark_word() const;
   virtual void set_saved_mark();
   void reset_gc_time_stamp() { _gc_time_stamp = 0; }
+  unsigned get_gc_time_stamp() { return _gc_time_stamp; }
 
   // See the comment above in the declaration of _pre_dummy_top for an
   // explanation of what it is.
@@ -439,6 +443,25 @@
     return _humongous_start_region;
   }
 
+  // Return the number of distinct regions that are covered by this region:
+  // 1 if the region is not humongous, >= 1 if the region is humongous.
+  uint region_num() const {
+    if (!isHumongous()) {
+      return 1U;
+    } else {
+      assert(startsHumongous(), "doesn't make sense on HC regions");
+      assert(capacity() % HeapRegion::GrainBytes == 0, "sanity");
+      return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes);
+    }
+  }
+
+  // Return the index + 1 of the last HC regions that's associated
+  // with this HS region.
+  uint last_hc_index() const {
+    assert(startsHumongous(), "don't call this otherwise");
+    return hrs_index() + region_num();
+  }
+
   // Same as Space::is_in_reserved, but will use the original size of the region.
   // The original size is different only for start humongous regions. They get
   // their _end set up to be the end of the last continues region of the
@@ -622,8 +645,8 @@
   bool is_marked() { return _prev_top_at_mark_start != bottom(); }
 
   void reset_during_compaction() {
-    guarantee( isHumongous() && startsHumongous(),
-               "should only be called for humongous regions");
+    assert(isHumongous() && startsHumongous(),
+           "should only be called for starts humongous regions");
 
     zero_marked_bytes();
     init_top_at_mark_start();
@@ -774,7 +797,7 @@
   virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
   SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DECL)
 
-  CompactibleSpace* next_compaction_space() const;
+  virtual CompactibleSpace* next_compaction_space() const;
 
   virtual void reset_after_compaction();