1 /*
   2  * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_GC_G1_G1MARKSWEEP_HPP
  26 #define SHARE_VM_GC_G1_G1MARKSWEEP_HPP
  27 
  28 #include "gc/g1/g1CollectedHeap.hpp"
  29 #include "gc/g1/heapRegion.hpp"
  30 #include "gc/serial/genMarkSweep.hpp"
  31 #include "gc/shared/generation.hpp"
  32 #include "memory/universe.hpp"
  33 #include "oops/markOop.hpp"
  34 #include "oops/oop.hpp"
  35 #include "runtime/timer.hpp"
  36 #include "utilities/growableArray.hpp"
  37 
  38 class ReferenceProcessor;
  39 
  40 // G1MarkSweep takes care of global mark-compact garbage collection for a
  41 // G1CollectedHeap using a four-phase pointer forwarding algorithm.  All
  42 // generations are assumed to support marking; those that can also support
  43 // compaction.
  44 //
  45 // Class unloading will only occur when a full gc is invoked.
  46 class G1PrepareCompactClosure;
  47 class G1ArchiveRegionMap;
  48 
  49 class G1MarkSweep : AllStatic {
  50  public:
  51 
  52   static void invoke_at_safepoint(ReferenceProcessor* rp,
  53                                   bool clear_all_softrefs);
  54 
  55   static STWGCTimer* gc_timer() { return GenMarkSweep::_gc_timer; }
  56   static SerialOldTracer* gc_tracer() { return GenMarkSweep::_gc_tracer; }
  57 
  58   // Create the _archive_region_map which is used to identify archive objects.
  59   static void enable_archive_object_check();
  60 
  61   // Set the regions containing the specified address range as archive/non-archive.
  62   static void set_range_archive(MemRegion range, bool is_archive);
  63 
  64   // Check if an object is in an archive region using the _archive_region_map.
  65   static bool in_archive_range(oop object);
  66 
  67   // Check if archive object checking is enabled, to avoid calling in_archive_range
  68   // unnecessarily.
  69   static bool archive_check_enabled() { return G1MarkSweep::_archive_check_enabled; }
  70 
  71  private:
  72   static bool _archive_check_enabled;
  73   static G1ArchiveRegionMap  _archive_region_map;
  74 
  75   // Mark live objects
  76   static void mark_sweep_phase1(GenMarkSweep* gms, bool& marked_for_deopt,
  77                                 bool clear_all_softrefs);
  78   // Calculate new addresses
  79   static void mark_sweep_phase2(GenMarkSweep* gms);
  80   // Update pointers
  81   static void mark_sweep_phase3(GenMarkSweep* gms);
  82   // Move objects to new positions
  83   static void mark_sweep_phase4(GenMarkSweep* gms);
  84 
  85   static void allocate_stacks(GenMarkSweep* gms);
  86   static void prepare_compaction();
  87   static void prepare_compaction_work(G1PrepareCompactClosure* blk);
  88 };
  89 
  90 class G1PrepareCompactClosure : public HeapRegionClosure {
  91  protected:
  92   G1CollectedHeap* _g1h;
  93   ModRefBarrierSet* _mrbs;
  94   CompactPoint _cp;
  95   uint _humongous_regions_removed;
  96 
  97   virtual void prepare_for_compaction(HeapRegion* hr, HeapWord* end);
  98   void prepare_for_compaction_work(CompactPoint* cp, HeapRegion* hr, HeapWord* end);
  99   void free_humongous_region(HeapRegion* hr);
 100   bool is_cp_initialized() const { return _cp.space != NULL; }
 101 
 102  public:
 103   G1PrepareCompactClosure() :
 104     _g1h(G1CollectedHeap::heap()),
 105     _mrbs(_g1h->g1_barrier_set()),
 106     _humongous_regions_removed(0) { }
 107 
 108   void update_sets();
 109   bool doHeapRegion(HeapRegion* hr);
 110 };
 111 
 112 // G1ArchiveRegionMap is a boolean array used to mark G1 regions as
 113 // archive regions.  This allows a quick check for whether an object
 114 // should not be marked because it is in an archive region.
 115 class G1ArchiveRegionMap : public G1BiasedMappedArray<bool> {
 116 protected:
 117   bool default_value() const { return false; }
 118 };
 119 
 120 #endif // SHARE_VM_GC_G1_G1MARKSWEEP_HPP