1 /*
   2  * Copyright (c) 2001, 2017, 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
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  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   static void enqueue_if_weak_or_archive(DecoratorSet decorators, oop value);
  58 
  59   template <class T> void write_ref_array_pre_work(T* dst, int count);
  60   virtual void write_ref_array_pre(oop* dst, int count, bool dest_uninitialized);
  61   virtual void write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized);
  62 
  63   template <DecoratorSet decorators, typename T>
  64   void write_ref_field_pre(T* field);
  65 
  66 /*
  67    Claimed and deferred bits are used together in G1 during the evacuation
  68    pause. These bits can have the following state transitions:
  69    1. The claimed bit can be put over any other card state. Except that
  70       the "dirty -> dirty and claimed" transition is checked for in
  71       G1 code and is not used.
  72    2. Deferred bit can be set only if the previous state of the card
  73       was either clean or claimed. mark_card_deferred() is wait-free.
  74       We do not care if the operation is be successful because if
  75       it does not it will only result in duplicate entry in the update
  76       buffer because of the "cache-miss". So it's not worth spinning.
  77  */
  78 
  79   bool is_card_claimed(size_t card_index) {
  80     jbyte val = _byte_map[card_index];
  81     return (val & (clean_card_mask_val() | claimed_card_val())) == claimed_card_val();
  82   }
  83 
  84   inline void set_card_claimed(size_t card_index);
  85 
  86   void verify_g1_young_region(MemRegion mr) PRODUCT_RETURN;
  87   void g1_mark_as_young(const MemRegion& mr);
  88 
  89   bool mark_card_deferred(size_t card_index);
  90 
  91   bool is_card_deferred(size_t card_index) {
  92     jbyte val = _byte_map[card_index];
  93     return (val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val();
  94   }
  95 };
  96 
  97 template<>
  98 struct BarrierSet::GetName<G1SATBCardTableModRefBS> {
  99   static const BarrierSet::Name value = BarrierSet::G1SATBCT;
 100 };
 101 
 102 template<>
 103 struct BarrierSet::GetType<BarrierSet::G1SATBCT> {
 104   typedef G1SATBCardTableModRefBS type;
 105 };
 106 
 107 class G1SATBCardTableLoggingModRefBSChangedListener : public G1MappingChangedListener {
 108  private:
 109   G1SATBCardTableLoggingModRefBS* _card_table;
 110  public:
 111   G1SATBCardTableLoggingModRefBSChangedListener() : _card_table(NULL) { }
 112 
 113   void set_card_table(G1SATBCardTableLoggingModRefBS* card_table) { _card_table = card_table; }
 114 
 115   virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled);
 116 };
 117 
 118 // Adds card-table logging to the post-barrier.
 119 // Usual invariant: all dirty cards are logged in the DirtyCardQueueSet.
 120 class G1SATBCardTableLoggingModRefBS: public G1SATBCardTableModRefBS {
 121   friend class G1SATBCardTableLoggingModRefBSChangedListener;
 122  private:
 123   G1SATBCardTableLoggingModRefBSChangedListener _listener;
 124   DirtyCardQueueSet& _dcqs;
 125 
 126  public:
 127   static size_t compute_size(size_t mem_region_size_in_words) {
 128     size_t number_of_slots = (mem_region_size_in_words / card_size_in_words);
 129     return ReservedSpace::allocation_align_size_up(number_of_slots);
 130   }
 131 
 132   // Returns how many bytes of the heap a single byte of the Card Table corresponds to.
 133   static size_t heap_map_factor() {
 134     return CardTableModRefBS::card_size;
 135   }
 136 
 137   G1SATBCardTableLoggingModRefBS(MemRegion whole_heap);
 138 
 139   virtual void initialize() { }
 140   virtual void initialize(G1RegionToSpaceMapper* mapper);
 141 
 142   virtual void resize_covered_region(MemRegion new_region) { ShouldNotReachHere(); }
 143 
 144   // NB: if you do a whole-heap invalidation, the "usual invariant" defined
 145   // above no longer applies.
 146   void invalidate(MemRegion mr);
 147 
 148   void write_region_work(MemRegion mr)    { invalidate(mr); }
 149   void write_ref_array_work(MemRegion mr) { invalidate(mr); }
 150 
 151   template <DecoratorSet decorators, typename T>
 152   void write_ref_field_post(T* field, oop new_val);
 153   void write_ref_field_post_slow(volatile jbyte* byte);
 154 
 155   // Callbacks for runtime accesses.
 156   template <DecoratorSet decorators, typename BarrierSetT = G1SATBCardTableLoggingModRefBS>
 157   class AccessBarrier: public ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT> {
 158     typedef ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT> ModRef;
 159     typedef BarrierSet::AccessBarrier<decorators, BarrierSetT> Raw;
 160 
 161   public:
 162     // Needed for loads on non-heap weak references
 163     template <typename T>
 164     static oop oop_load_not_in_heap(T* addr);
 165 
 166     // Needed for non-heap stores
 167     template <typename T>
 168     static void oop_store_not_in_heap(T* addr, oop new_value);
 169 
 170     // Needed for weak references
 171     static oop oop_load_in_heap_at(oop base, ptrdiff_t offset);
 172 
 173     // Defensive: will catch weak oops at addresses in heap
 174     template <typename T>
 175     static oop oop_load_in_heap(T* addr);
 176   };
 177 };
 178 
 179 template<>
 180 struct BarrierSet::GetName<G1SATBCardTableLoggingModRefBS> {
 181   static const BarrierSet::Name value = BarrierSet::G1SATBCTLogging;
 182 };
 183 
 184 template<>
 185 struct BarrierSet::GetType<BarrierSet::G1SATBCTLogging> {
 186   typedef G1SATBCardTableLoggingModRefBS type;
 187 };
 188 
 189 #endif // SHARE_VM_GC_G1_G1SATBCARDTABLEMODREFBS_HPP