1/*
2 * Copyright (c) 2013, 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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
24
25#ifndef SHARE_GC_G1_G1CARDCOUNTS_HPP
26#define SHARE_GC_G1_G1CARDCOUNTS_HPP
27
28#include "gc/g1/g1CardTable.hpp"
29#include "gc/g1/g1RegionToSpaceMapper.hpp"
30#include "memory/allocation.hpp"
31#include "memory/virtualspace.hpp"
32#include "utilities/globalDefinitions.hpp"
33
34class CardTableBarrierSet;
35class G1CardCounts;
36class G1CollectedHeap;
37class G1RegionToSpaceMapper;
38class HeapRegion;
39
40class G1CardCountsMappingChangedListener : public G1MappingChangedListener {
41 private:
42 G1CardCounts* _counts;
43 public:
44 void set_cardcounts(G1CardCounts* counts) { _counts = counts; }
45
46 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled);
47};
48
49// Table to track the number of times a card has been refined. Once
50// a card has been refined a certain number of times, it is
51// considered 'hot' and its refinement is delayed by inserting the
52// card into the hot card cache. The card will then be refined when
53// it is evicted from the hot card cache, or when the hot card cache
54// is 'drained' during the next evacuation pause.
55
56class G1CardCounts: public CHeapObj<mtGC> {
57public:
58 typedef CardTable::CardValue CardValue;
59
60private:
61 G1CardCountsMappingChangedListener _listener;
62
63 G1CollectedHeap* _g1h;
64 G1CardTable* _ct;
65
66 // The table of counts
67 uint8_t* _card_counts;
68
69 // Max capacity of the reserved space for the counts table
70 size_t _reserved_max_card_num;
71
72 // CardTable bottom.
73 const CardValue* _ct_bot;
74
75 // Returns true if the card counts table has been reserved.
76 bool has_reserved_count_table() { return _card_counts != NULL; }
77
78 // Returns true if the card counts table has been reserved and committed.
79 bool has_count_table() {
80 return has_reserved_count_table();
81 }
82
83 size_t ptr_2_card_num(const CardValue* card_ptr) {
84 assert(card_ptr >= _ct_bot,
85 "Invalid card pointer: "
86 "card_ptr: " PTR_FORMAT ", "
87 "_ct_bot: " PTR_FORMAT,
88 p2i(card_ptr), p2i(_ct_bot));
89 size_t card_num = pointer_delta(card_ptr, _ct_bot, sizeof(CardValue));
90 assert(card_num < _reserved_max_card_num,
91 "card pointer out of range: " PTR_FORMAT, p2i(card_ptr));
92 return card_num;
93 }
94
95 CardValue* card_num_2_ptr(size_t card_num) {
96 assert(card_num < _reserved_max_card_num,
97 "card num out of range: " SIZE_FORMAT, card_num);
98 return (CardValue*) (_ct_bot + card_num);
99 }
100
101 // Clear the counts table for the given (exclusive) index range.
102 void clear_range(size_t from_card_num, size_t to_card_num);
103
104 public:
105 G1CardCounts(G1CollectedHeap* g1h);
106
107 // Return the number of slots needed for a card counts table
108 // that covers mem_region_words words.
109 static size_t compute_size(size_t mem_region_size_in_words);
110
111 // Returns how many bytes of the heap a single byte of the card counts table
112 // corresponds to.
113 static size_t heap_map_factor();
114
115 void initialize(G1RegionToSpaceMapper* mapper);
116
117 // Increments the refinement count for the given card.
118 // Returns the pre-increment count value.
119 uint add_card_count(CardValue* card_ptr);
120
121 // Returns true if the given count is high enough to be considered
122 // 'hot'; false otherwise.
123 bool is_hot(uint count);
124
125 // Clears the card counts for the cards spanned by the region
126 void clear_region(HeapRegion* hr);
127
128 // Clears the card counts for the cards spanned by the MemRegion
129 void clear_range(MemRegion mr);
130
131 // Clear the entire card counts table during GC.
132 void clear_all();
133};
134
135#endif // SHARE_GC_G1_G1CARDCOUNTS_HPP
136