diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/gc/g1/g1CardLiveData.hpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/g1CardLiveData.hpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,112 @@
+/*
+ * Copyright (c) 2016, 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.
+ *
+ */
+
+#ifndef SHARE_VM_GC_G1_G1CARDLIVEDATA_HPP
+#define SHARE_VM_GC_G1_G1CARDLIVEDATA_HPP
+
+#include "gc/g1/g1CollectedHeap.hpp"
+#include "utilities/bitMap.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+class G1CollectedHeap;
+class G1CMBitMap;
+class WorkGang;
+
+// Information about object liveness on the Java heap on a "card" basis.
+// Can be used for various purposes, like as remembered set for completely
+// coarsened remembered sets, scrubbing remembered sets or estimating liveness.
+// This information is created as part of the concurrent marking cycle.
+class G1CardLiveData VALUE_OBJ_CLASS_SPEC {
+  friend class G1CardLiveDataHelper;
+  friend class G1VerifyCardLiveDataTask;
+private:
+  typedef BitMap::bm_word_t bm_word_t;
+  // Store some additional information about the covered area to be able to test.
+  size_t _max_capacity;
+  size_t _cards_per_region;
+
+  // Regions may be reclaimed while concurrently creating live data (e.g. due to humongous
+  // eager reclaim). This results in wrong live data for these regions at the end.
+  // So we need to somehow detect these regions, and during live data finalization completely
+  // recreate their information.
+  // This _gc_timestamp_at_create tracks the global timestamp when live data creation
+  // has started. Any regions with a higher time stamp have been cleared after that
+  // point in time, and need re-finalization.
+  // Unsynchronized access to this variable is okay, since this value is only set during a
+  // concurrent phase, and read only at the Cleanup safepoint. I.e. there is always
+  // full memory synchronization inbetween.
+  uint _gc_timestamp_at_create;
+  // The per-card liveness bitmap.
+  bm_word_t* _live_cards;
+  size_t _live_cards_size_in_bits;
+  // The per-region liveness bitmap.
+  bm_word_t* _live_regions;
+  size_t _live_regions_size_in_bits;
+  // The bits in this bitmap contain for every card whether it contains
+  // at least part of at least one live object.
+  BitMapView live_cards_bm() const { return BitMapView(_live_cards, _live_cards_size_in_bits); }
+  // The bits in this bitmap indicate that a given region contains some live objects.
+  BitMapView live_regions_bm() const { return BitMapView(_live_regions, _live_regions_size_in_bits); }
+
+  // Allocate a "large" bitmap from virtual memory with the given size in bits.
+  bm_word_t* allocate_large_bitmap(size_t size_in_bits);
+  void free_large_bitmap(bm_word_t* map, size_t size_in_bits);
+
+  inline BitMapView live_card_bitmap(uint region);
+
+  inline bool is_card_live_at(BitMap::idx_t idx) const;
+
+  size_t live_region_bitmap_size_in_bits() const;
+  size_t live_card_bitmap_size_in_bits() const;
+public:
+  uint gc_timestamp_at_create() const { return _gc_timestamp_at_create; }
+
+  inline bool is_region_live(uint region) const;
+
+  inline void remove_nonlive_cards(uint region, BitMap* bm);
+  inline void remove_nonlive_regions(BitMap* bm);
+
+  G1CardLiveData();
+  ~G1CardLiveData();
+
+  void initialize(size_t max_capacity, uint num_max_regions);
+  void pretouch();
+
+  // Create the initial liveness data based on the marking result from the bottom
+  // to the ntams of every region in the heap and the marks in the given bitmap.
+  void create(WorkGang* workers, G1CMBitMap* mark_bitmap);
+  // Finalize the liveness data.
+  void finalize(WorkGang* workers, G1CMBitMap* mark_bitmap);
+
+  // Verify that the liveness count data created concurrently matches one created
+  // during this safepoint.
+  void verify(WorkGang* workers, G1CMBitMap* actual_bitmap);
+  // Clear all data structures, prepare for next processing.
+  void clear(WorkGang* workers);
+
+  void verify_is_clear() PRODUCT_RETURN;
+};
+
+#endif /* SHARE_VM_GC_G1_G1CARDLIVEDATA_HPP */
+