1 /*
   2  * Copyright (c) 2001, 2019, 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_GC_PARALLEL_PSCARDTABLE_HPP
  26 #define SHARE_GC_PARALLEL_PSCARDTABLE_HPP
  27 
  28 #include "gc/shared/cardTable.hpp"
  29 #include "oops/oop.hpp"
  30 
  31 class MutableSpace;
  32 class ObjectStartArray;
  33 class PSPromotionManager;
  34 
  35 class PSCardTable: public CardTable {
  36  private:
  37   // Support methods for resizing the card table.
  38   // resize_commit_uncommit() returns true if the pages were committed or
  39   // uncommitted
  40   bool resize_commit_uncommit(int changed_region, MemRegion new_region);
  41   void resize_update_card_table_entries(int changed_region,
  42                                         MemRegion new_region);
  43   void resize_update_committed_table(int changed_region, MemRegion new_region);
  44   void resize_update_covered_table(int changed_region, MemRegion new_region);
  45 
  46   void verify_all_young_refs_precise_helper(MemRegion mr);
  47 
  48   enum ExtendedCardValue {
  49     youngergen_card   = CT_MR_BS_last_reserved + 1,
  50     verify_card       = CT_MR_BS_last_reserved + 5
  51   };
  52 
  53  public:
  54   PSCardTable(MemRegion whole_heap) : CardTable(whole_heap, /* scanned_concurrently */ false) {}
  55 
  56   static CardValue youngergen_card_val() { return youngergen_card; }
  57   static CardValue verify_card_val()     { return verify_card; }
  58 
  59   // Scavenge support
  60   void scavenge_contents_parallel(ObjectStartArray* start_array,
  61                                   MutableSpace* sp,
  62                                   HeapWord* space_top,
  63                                   PSPromotionManager* pm,
  64                                   uint stripe_number,
  65                                   uint stripe_total);
  66 
  67   bool addr_is_marked_imprecise(void *addr);
  68   bool addr_is_marked_precise(void *addr);
  69 
  70   void set_card_newgen(void* addr)   { CardValue* p = byte_for(addr); *p = verify_card; }
  71 
  72   // Testers for entries
  73   static bool card_is_dirty(int value)      { return value == dirty_card; }
  74   static bool card_is_newgen(int value)     { return value == youngergen_card; }
  75   static bool card_is_clean(int value)      { return value == clean_card; }
  76   static bool card_is_verify(int value)     { return value == verify_card; }
  77 
  78   // Card marking
  79   void inline_write_ref_field_gc(void* field, oop new_val) {
  80     CardValue* byte = byte_for(field);
  81     *byte = youngergen_card;
  82   }
  83 
  84   // ReduceInitialCardMarks support
  85   bool is_in_young(oop obj) const;
  86 
  87   // Adaptive size policy support
  88   // Allows adjustment of the base and size of the covered regions
  89   void resize_covered_region(MemRegion new_region);
  90   // Finds the covered region to resize based on the start address
  91   // of the covered regions.
  92   void resize_covered_region_by_start(MemRegion new_region);
  93   // Finds the covered region to resize based on the end address
  94   // of the covered regions.
  95   void resize_covered_region_by_end(int changed_region, MemRegion new_region);
  96   // Finds the lowest start address of a covered region that is
  97   // previous (i.e., lower index) to the covered region with index "ind".
  98   HeapWord* lowest_prev_committed_start(int ind) const;
  99 
 100 #ifdef ASSERT
 101   bool is_valid_card_address(CardValue* addr) {
 102     return (addr >= _byte_map) && (addr < _byte_map + _byte_map_size);
 103   }
 104 #endif // ASSERT
 105 
 106   // Verification
 107   void verify_all_young_refs_imprecise();
 108   void verify_all_young_refs_precise();
 109 };
 110 
 111 #endif // SHARE_GC_PARALLEL_PSCARDTABLE_HPP