1 /*
2 * Copyright (c) 2018, 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.
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23 */
24
25 #ifndef SHARE_MEMORY_METASPACE_COMMITMASK_HPP
26 #define SHARE_MEMORY_METASPACE_COMMITMASK_HPP
27
28 #include "memory/metaspace/constants.hpp"
29 #include "utilities/debug.hpp"
30 #include "utilities/bitMap.hpp"
31 #include "utilities/globalDefinitions.hpp"
32
33 namespace metaspace {
34
35 // A bitmap covering a range of metaspace; each bit in this mask corresponds to
36 //
37 class CommitMask : private CHeapBitMap {
38
39 const MetaWord* const _base;
40 const size_t _word_size;
41
42 // Given an offset, in words, into the area, return the number of the bit
43 // covering it.
44 static idx_t bitno_for_word_offset(size_t offset) {
45 return offset / constants::commit_granule_words;
46 }
47
48 idx_t bitno_for_address(const MetaWord* p) const {
49 assert(p >= _base && p < _base + _word_size, "Invalid address");
50 const size_t off = p - _base;
51 return bitno_for_word_offset(off);
52 }
53
54 static idx_t mask_size(size_t word_size) {
55 assert(is_aligned(word_size, constants::commit_granule_words), "size not aligned correctly.");
56 return bitno_for_word_offset(word_size) + 1;
57 }
58
59 struct BitCounterClosure : public BitMapClosure {
60 idx_t cnt;
61 bool do_bit(BitMap::idx_t offset) { cnt ++; return true; }
62 };
63
64 // Missing from BitMap.
65 // Count 1 bits in range [start, end).
66 idx_t count_one_bits_in_range(idx_t start, idx_t end) const {
67 if (start == end) {
68 return at(start) ? 1 : 0;
69 }
70 // TODO: This can be done more efficiently.
71 BitCounterClosure bcc;
72 bcc.cnt = 0;
73 iterate(&bcc, start, end + 1);
74 return bcc.cnt;
75 }
76
77 #ifdef ASSERT
78 // Given a pointer, check if it points into the range this bitmap covers.
79 bool is_pointer_valid(const MetaWord* p) const {
80 return p >= _base && p < _base + _word_size;
81 }
82 // Given a pointer, check if it points into the range this bitmap covers,
83 // and if it is aligned to commit granule border.
84 bool is_pointer_valid_and_aligned(const MetaWord* p) const {
85 return is_pointer_valid(p) && is_aligned(p, constants::commit_granule_bytes);
86 }
87 // Given a pointer, check if it points into the range this bitmap covers.
88 void check_pointer(const MetaWord* p) const {
89 assert(is_pointer_valid(p),
90 "Pointer " PTR_FORMAT " not in range of this bitmap [" PTR_FORMAT ", " PTR_FORMAT ").",
91 p2i(p), p2i(_base), p2i(_base + _word_size));
92 }
93 // Given a pointer, check if it points into the range this bitmap covers,
94 // and if it is aligned to commit granule border.
95 void check_pointer_aligned(const MetaWord* p) const {
96 check_pointer(p);
97 assert(is_aligned(p, constants::commit_granule_bytes),
98 "Pointer " PTR_FORMAT " should be aligned to commit granule size " SIZE_FORMAT ".", p2i(p), constants::commit_granule_bytes);
99 }
100 // Given a range, check if it points into the range this bitmap covers,
101 // and if its borders are aligned to commit granule border.
102 void check_range(const MetaWord* start, size_t word_size) const {
103 check_pointer_aligned(start);
104 check_pointer_aligned(start + word_size);
105 }
106 #endif
107
108 // Marks a single commit granule as committed or uncomitted and returns
109 // its prior state.
110 bool mark_granule(idx_t bitno, bool value) {
111 bool b = at(bitno);
112 at_put(bitno, value);
113 return b;
114 }
115
116 public:
117
118 CommitMask(const MetaWord* start, size_t word_size)
119 : CHeapBitMap(mask_size(word_size))
120 , _base(start)
121 , _word_size(word_size)
122 {}
123
124 virtual ~CommitMask() {}
125
126 // Given an address, returns true if the address is committed, false if not.
127 bool is_committed_address(const MetaWord* p) const {
128 DEBUG_ONLY(check_pointer(p));
129 const idx_t bitno = bitno_for_address(p);
130 return at(bitno);
131 }
132
133 // Given an address range [start, end), returns true if area is fully committed through.
134 bool is_fully_committed_range(const MetaWord* start, size_t word_size) const {
135 DEBUG_ONLY(check_range(start, word_size));
136 const idx_t b1 = bitno_for_address(start);
137 const idx_t b2 = bitno_for_address(start + word_size);
138 return get_next_zero_offset(b1, b2) == b2;
139 }
140
141 // Given an address range, return size, in number of words, of committed area within that range.
142 size_t get_committed_size_in_range(const MetaWord* start, size_t word_size) const {
143 DEBUG_ONLY(check_range(start, word_size));
144 const idx_t b1 = bitno_for_address(start);
145 const idx_t b2 = bitno_for_address(start + word_size);
146 const idx_t num_bits = count_one_bits_in_range(b1, b2);
147 return num_bits * constants::commit_granule_words;
148 }
149
150 // Return total committed size, in number of words.
151 size_t get_committed_size() const {
152 return count_one_bits() * constants::commit_granule_words;
153 }
154
155 // Mark a whole address range [start, end) as committed.
156 // Return the number of words which had already been committed before this operation.
157 size_t mark_range_as_committed(const MetaWord* start, size_t word_size) {
158 DEBUG_ONLY(check_range(start, word_size));
159 const idx_t b1 = bitno_for_address(start);
160 const idx_t b2 = bitno_for_address(start + word_size);
161 if (b1 == b2) { // Simple case, 1 granule
162 return mark_granule(b1, true) ? constants::commit_granule_words : 0;
163 }
164 const idx_t bits_set_before = count_one_bits_in_range(bitno_for_address(start), word_size);
165 set_range(b1, b2);
166 return bits_set_before * constants::commit_granule_words;
167 }
168
169 // Mark a whole address range [start, end) as uncommitted.
170 // Return the number of words which had already been uncommitted before this operation.
171 size_t mark_range_as_uncommitted(const MetaWord* start, size_t word_size) {
172 DEBUG_ONLY(check_range(start, word_size));
173 const idx_t b1 = bitno_for_address(start);
174 const idx_t b2 = bitno_for_address(start + word_size);
175 if (b1 == b2) { // Simple case, 1 granule
176 return mark_granule(b1, true) ? constants::commit_granule_words : 0;
177 }
178 const idx_t bits_set_before = count_one_bits_in_range(bitno_for_address(start), word_size);
179 clear_range(b1, b2);
180 return ((b2 - b1) - bits_set_before) * constants::commit_granule_words;
181 }
182
183
184 //// Debug stuff ////
185 DEBUG_ONLY(void verify(bool slow) const;)
186
187 };
188
189 } // namespace metaspace
190
191 #endif // SHARE_MEMORY_METASPACE_COMMITMASK_HPP