1 /*
   2  * Copyright (c) 2001, 2016, 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_G1SATBCARDTABLEMODREFBS_HPP
  26 #define SHARE_VM_GC_G1_G1SATBCARDTABLEMODREFBS_HPP
  27 
  28 #include "gc/g1/g1RegionToSpaceMapper.hpp"
  29 #include "gc/shared/cardTableModRefBS.hpp"
  30 #include "memory/memRegion.hpp"
  31 #include "oops/oop.hpp"
  32 #include "utilities/macros.hpp"
  33 
  34 class DirtyCardQueueSet;
  35 class G1SATBCardTableLoggingModRefBS;
  36 
  37 // This barrier is specialized to use a logging barrier to support
  38 // snapshot-at-the-beginning marking.
  39 
  40 class G1SATBCardTableModRefBS: public CardTableModRefBS {
  41   friend class VMStructs;
  42 protected:
  43   enum G1CardValues {
  44     g1_young_gen = CT_MR_BS_last_reserved << 1
  45   };
  46 
  47   G1SATBCardTableModRefBS(MemRegion whole_heap, const BarrierSet::FakeRtti& fake_rtti);
  48   ~G1SATBCardTableModRefBS() { }
  49 
  50 public:
  51   static int g1_young_card_val()   { return g1_young_gen; }
  52 
  53   // Add "pre_val" to a set of objects that may have been disconnected from the
  54   // pre-marking object graph.
  55   static void enqueue(oop pre_val);
  56 
  57   virtual bool has_write_ref_pre_barrier() { return true; }
  58 
  59   // We export this to make it available in cases where the static
  60   // type of the barrier set is known.  Note that it is non-virtual.
  61   template <class T> inline void inline_write_ref_field_pre(T* field, oop newVal);
  62 
  63   // These are the more general virtual versions.
  64   inline virtual void write_ref_field_pre_work(oop* field, oop new_val);
  65   inline virtual void write_ref_field_pre_work(narrowOop* field, oop new_val);
  66   virtual void write_ref_field_pre_work(void* field, oop new_val) {
  67     guarantee(false, "Not needed");
  68   }
  69 
  70   template <class T> void write_ref_array_pre_work(T* dst, int count);
  71   virtual void write_ref_array_pre(oop* dst, int count, bool dest_uninitialized);
  72   virtual void write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized);
  73 
  74 /*
  75    Claimed and deferred bits are used together in G1 during the evacuation
  76    pause. These bits can have the following state transitions:
  77    1. The claimed bit can be put over any other card state. Except that
  78       the "dirty -> dirty and claimed" transition is checked for in
  79       G1 code and is not used.
  80    2. Deferred bit can be set only if the previous state of the card
  81       was either clean or claimed. mark_card_deferred() is wait-free.
  82       We do not care if the operation is be successful because if
  83       it does not it will only result in duplicate entry in the update
  84       buffer because of the "cache-miss". So it's not worth spinning.
  85  */
  86 
  87   bool is_card_claimed(size_t card_index) {
  88     jbyte val = _byte_map[card_index];
  89     return (val & (clean_card_mask_val() | claimed_card_val())) == claimed_card_val();
  90   }
  91 
  92   inline void set_card_claimed(size_t card_index);
  93 
  94   void verify_g1_young_region(MemRegion mr) PRODUCT_RETURN;
  95   void g1_mark_as_young(const MemRegion& mr);
  96 
  97   bool mark_card_deferred(size_t card_index);
  98 
  99   bool is_card_deferred(size_t card_index) {
 100     jbyte val = _byte_map[card_index];
 101     return (val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val();
 102   }
 103   virtual void write_ref_nmethod_pre(oop* dst, nmethod* nm);
 104   virtual void write_ref_nmethod_post(oop* dst, nmethod* nm);
 105 
 106 };
 107 
 108 template<>
 109 struct BarrierSet::GetName<G1SATBCardTableModRefBS> {
 110   static const BarrierSet::Name value = BarrierSet::G1SATBCT;
 111 };
 112 
 113 class G1SATBCardTableLoggingModRefBSChangedListener : public G1MappingChangedListener {
 114  private:
 115   G1SATBCardTableLoggingModRefBS* _card_table;
 116  public:
 117   G1SATBCardTableLoggingModRefBSChangedListener() : _card_table(NULL) { }
 118 
 119   void set_card_table(G1SATBCardTableLoggingModRefBS* card_table) { _card_table = card_table; }
 120 
 121   virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled);
 122 };
 123 
 124 // Adds card-table logging to the post-barrier.
 125 // Usual invariant: all dirty cards are logged in the DirtyCardQueueSet.
 126 class G1SATBCardTableLoggingModRefBS: public G1SATBCardTableModRefBS {
 127   friend class G1SATBCardTableLoggingModRefBSChangedListener;
 128  private:
 129   G1SATBCardTableLoggingModRefBSChangedListener _listener;
 130   DirtyCardQueueSet& _dcqs;
 131 
 132  protected:
 133   virtual void write_ref_field_work(void* field, oop new_val, bool release);
 134 
 135  public:
 136   static size_t compute_size(size_t mem_region_size_in_words) {
 137     size_t number_of_slots = (mem_region_size_in_words / card_size_in_words);
 138     return ReservedSpace::allocation_align_up(number_of_slots);
 139   }
 140 
 141   // Returns how many bytes of the heap a single byte of the Card Table corresponds to.
 142   static size_t heap_map_factor() {
 143     return CardTableModRefBS::card_size;
 144   }
 145 
 146   G1SATBCardTableLoggingModRefBS(MemRegion whole_heap);
 147 
 148   virtual void initialize() { }
 149   virtual void initialize(G1RegionToSpaceMapper* mapper);
 150 
 151   virtual void resize_covered_region(MemRegion new_region) { ShouldNotReachHere(); }
 152 
 153   // NB: if you do a whole-heap invalidation, the "usual invariant" defined
 154   // above no longer applies.
 155   void invalidate(MemRegion mr);
 156 
 157   void write_region_work(MemRegion mr)    { invalidate(mr); }
 158   void write_ref_array_work(MemRegion mr) { invalidate(mr); }
 159 };
 160 
 161 template<>
 162 struct BarrierSet::GetName<G1SATBCardTableLoggingModRefBS> {
 163   static const BarrierSet::Name value = BarrierSet::G1SATBCTLogging;
 164 };
 165 
 166 #endif // SHARE_VM_GC_G1_G1SATBCARDTABLEMODREFBS_HPP