1 /*
2 * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2020 SAP SE. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #ifndef SHARE_MEMORY_METASPACE_MSCOMMITMASK_HPP
27 #define SHARE_MEMORY_METASPACE_MSCOMMITMASK_HPP
28
29 #include "utilities/debug.hpp"
30 #include "utilities/bitMap.hpp"
31 #include "utilities/globalDefinitions.hpp"
32
33 class outputStream;
34
35 namespace metaspace {
36
37 // The CommitMask is a bitmask used to store the commit state of commit granules.
38 // It keeps one bit per granule; 1 means committed, 0 means uncommitted.
39
40 class CommitMask : public CHeapBitMap {
41
42 const MetaWord* const _base;
43 const size_t _word_size;
44 const size_t _words_per_bit;
45
46 // Given an offset, in words, into the area, return the number of the bit
47 // covering it.
48 static idx_t bitno_for_word_offset(size_t offset, size_t words_per_bit) {
49 return offset / words_per_bit;
50 }
51
52 idx_t bitno_for_address(const MetaWord* p) const {
53 // Note: we allow one-beyond since this is a typical need.
54 assert(p >= _base && p <= _base + _word_size, "Invalid address");
55 const size_t off = p - _base;
56 return bitno_for_word_offset(off, _words_per_bit);
57 }
58
59 static idx_t mask_size(size_t word_size, size_t words_per_bit) {
60 return bitno_for_word_offset(word_size, words_per_bit);
61 }
62
63 #ifdef ASSERT
64 // Given a pointer, check if it points into the range this bitmap covers.
65 bool is_pointer_valid(const MetaWord* p) const {
66 return p >= _base && p < _base + _word_size;
67 }
68
69 // Given a pointer, check if it points into the range this bitmap covers.
70 void check_pointer(const MetaWord* p) const {
71 assert(is_pointer_valid(p),
72 "Pointer " PTR_FORMAT " not in range of this bitmap [" PTR_FORMAT ", " PTR_FORMAT ").",
73 p2i(p), p2i(_base), p2i(_base + _word_size));
74 }
75 // Given a pointer, check if it points into the range this bitmap covers,
76 // and if it is aligned to commit granule border.
77 void check_pointer_aligned(const MetaWord* p) const {
78 check_pointer(p);
79 assert(is_aligned(p, _words_per_bit * BytesPerWord),
80 "Pointer " PTR_FORMAT " should be aligned to commit granule size " SIZE_FORMAT ".",
81 p2i(p), _words_per_bit * BytesPerWord);
82 }
83 // Given a range, check if it points into the range this bitmap covers,
84 // and if its borders are aligned to commit granule border.
85 void check_range(const MetaWord* start, size_t word_size) const {
86 check_pointer_aligned(start);
87 assert(is_aligned(word_size, _words_per_bit),
88 "Range " SIZE_FORMAT " should be aligned to commit granule size " SIZE_FORMAT ".",
89 word_size, _words_per_bit);
90 check_pointer(start + word_size - 1);
91 }
92 #endif
93
94 // Marks a single commit granule as committed (value == true)
95 // or uncomitted (value == false) and returns
96 // its prior state.
97 bool mark_granule(idx_t bitno, bool value) {
98 bool b = at(bitno);
99 at_put(bitno, value);
100 return b;
101 }
102
103 public:
104
105 // Create a commit mask covering a range [start, start + word_size).
106 CommitMask(const MetaWord* start, size_t word_size);
107
108 const MetaWord* base() const { return _base; }
109 size_t word_size() const { return _word_size; }
110 const MetaWord* end() const { return _base + word_size(); }
111
112 // Given an address, returns true if the address is committed, false if not.
113 bool is_committed_address(const MetaWord* p) const {
114 DEBUG_ONLY(check_pointer(p));
115 const idx_t bitno = bitno_for_address(p);
116 return at(bitno);
117 }
118
119 // Given an address range, return size, in number of words, of committed area within that range.
120 size_t get_committed_size_in_range(const MetaWord* start, size_t word_size) const {
121 DEBUG_ONLY(check_range(start, word_size));
122 assert(word_size > 0, "zero range");
123 const idx_t b1 = bitno_for_address(start);
124 const idx_t b2 = bitno_for_address(start + word_size);
125 const idx_t num_bits = count_one_bits(b1, b2);
126 return num_bits * _words_per_bit;
127 }
128
129 // Return total committed size, in number of words.
130 size_t get_committed_size() const {
131 return count_one_bits() * _words_per_bit;
132 }
133
134 // Mark a whole address range [start, end) as committed.
135 // Return the number of words which had already been committed before this operation.
136 size_t mark_range_as_committed(const MetaWord* start, size_t word_size) {
137 DEBUG_ONLY(check_range(start, word_size));
138 assert(word_size > 0, "zero range");
139 const idx_t b1 = bitno_for_address(start);
140 const idx_t b2 = bitno_for_address(start + word_size);
141 if (b1 == b2) { // Simple case, 1 granule
142 bool was_committed = mark_granule(b1, true);
143 return was_committed ? _words_per_bit : 0;
144 }
145 const idx_t one_bits_in_range_before = count_one_bits(b1, b2);
146 set_range(b1, b2);
147 return one_bits_in_range_before * _words_per_bit;
148 }
149
150 // Mark a whole address range [start, end) as uncommitted.
151 // Return the number of words which had already been uncommitted before this operation.
152 size_t mark_range_as_uncommitted(const MetaWord* start, size_t word_size) {
153 DEBUG_ONLY(check_range(start, word_size));
154 assert(word_size > 0, "zero range");
155 const idx_t b1 = bitno_for_address(start);
156 const idx_t b2 = bitno_for_address(start + word_size);
157 if (b1 == b2) { // Simple case, 1 granule
158 bool was_committed = mark_granule(b1, false);
159 return was_committed ? 0 : _words_per_bit;
160 }
161 const idx_t zero_bits_in_range_before =
162 (b2 - b1) - count_one_bits(b1, b2);
163 clear_range(b1, b2);
164 return zero_bits_in_range_before * _words_per_bit;
165 }
166
167 //// Debug stuff ////
168
169 // Verify internals.
170 DEBUG_ONLY(void verify() const;)
171
172 void print_on(outputStream* st) const;
173
174 };
175
176 } // namespace metaspace
177
178 #endif // SHARE_MEMORY_METASPACE_MSCOMMITMASK_HPP