1 /*
2 * Copyright (c) 2013, 2018, 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_G1CARDCOUNTS_HPP
26 #define SHARE_VM_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
34 class CardTableModRefBS;
35 class G1CardCounts;
36 class G1CollectedHeap;
37 class G1RegionToSpaceMapper;
38 class HeapRegion;
39
40 class 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
56 class G1CardCounts: public CHeapObj<mtGC> {
57 G1CardCountsMappingChangedListener _listener;
58
59 G1CollectedHeap* _g1h;
60 G1CardTable* _ct;
61
62 // The table of counts
63 jubyte* _card_counts;
64
65 // Max capacity of the reserved space for the counts table
66 size_t _reserved_max_card_num;
67
68 // CardTable bottom.
69 const jbyte* _ct_bot;
70
71 // Returns true if the card counts table has been reserved.
72 bool has_reserved_count_table() { return _card_counts != NULL; }
73
74 // Returns true if the card counts table has been reserved and committed.
75 bool has_count_table() {
76 return has_reserved_count_table();
77 }
78
79 size_t ptr_2_card_num(const jbyte* card_ptr) {
80 assert(card_ptr >= _ct_bot,
81 "Invalid card pointer: "
82 "card_ptr: " PTR_FORMAT ", "
83 "_ct_bot: " PTR_FORMAT,
84 p2i(card_ptr), p2i(_ct_bot));
85 size_t card_num = pointer_delta(card_ptr, _ct_bot, sizeof(jbyte));
86 assert(card_num < _reserved_max_card_num,
87 "card pointer out of range: " PTR_FORMAT, p2i(card_ptr));
88 return card_num;
89 }
90
91 jbyte* card_num_2_ptr(size_t card_num) {
92 assert(card_num < _reserved_max_card_num,
93 "card num out of range: " SIZE_FORMAT, card_num);
94 return (jbyte*) (_ct_bot + card_num);
95 }
96
97 // Clear the counts table for the given (exclusive) index range.
98 void clear_range(size_t from_card_num, size_t to_card_num);
99
100 public:
101 G1CardCounts(G1CollectedHeap* g1h);
102
103 // Return the number of slots needed for a card counts table
104 // that covers mem_region_words words.
105 static size_t compute_size(size_t mem_region_size_in_words);
106
107 // Returns how many bytes of the heap a single byte of the card counts table
108 // corresponds to.
109 static size_t heap_map_factor();
110
111 void initialize(G1RegionToSpaceMapper* mapper);
112
113 // Increments the refinement count for the given card.
114 // Returns the pre-increment count value.
115 uint add_card_count(jbyte* card_ptr);
116
117 // Returns true if the given count is high enough to be considered
118 // 'hot'; false otherwise.
119 bool is_hot(uint count);
120
121 // Clears the card counts for the cards spanned by the region
122 void clear_region(HeapRegion* hr);
123
124 // Clears the card counts for the cards spanned by the MemRegion
125 void clear_range(MemRegion mr);
126
127 // Clear the entire card counts table during GC.
128 void clear_all();
129 };
130
131 #endif // SHARE_VM_GC_G1_G1CARDCOUNTS_HPP