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_COMMITMASK_HPP 27 #define SHARE_MEMORY_METASPACE_COMMITMASK_HPP 28 29 #include "utilities/bitMap.hpp" 30 #include "utilities/debug.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. bitno_for_word_offset(size_t offset,size_t words_per_bit)48 static idx_t bitno_for_word_offset(size_t offset, size_t words_per_bit) { 49 return offset / words_per_bit; 50 } 51 bitno_for_address(const MetaWord * p) const52 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 mask_size(size_t word_size,size_t words_per_bit)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 // Marks a single commit granule as committed (value == true) 64 // or uncomitted (value == false) and returns 65 // its prior state. mark_granule(idx_t bitno,bool value)66 bool mark_granule(idx_t bitno, bool value) { 67 bool b = at(bitno); 68 at_put(bitno, value); 69 return b; 70 } 71 72 #ifdef ASSERT 73 74 // Given a pointer, check if it points into the range this bitmap covers. 75 bool is_pointer_valid(const MetaWord* p) const; 76 77 // Given a pointer, check if it points into the range this bitmap covers. 78 void check_pointer(const MetaWord* p) const; 79 80 // Given a pointer, check if it points into the range this bitmap covers, 81 // and if it is aligned to commit granule border. 82 void check_pointer_aligned(const MetaWord* p) const; 83 84 // Given a range, check if it points into the range this bitmap covers, 85 // and if its borders are aligned to commit granule border. 86 void check_range(const MetaWord* start, size_t word_size) const; 87 88 #endif // ASSERT 89 90 public: 91 92 // Create a commit mask covering a range [start, start + word_size). 93 CommitMask(const MetaWord* start, size_t word_size); 94 base() const95 const MetaWord* base() const { return _base; } word_size() const96 size_t word_size() const { return _word_size; } end() const97 const MetaWord* end() const { return _base + word_size(); } 98 99 // Given an address, returns true if the address is committed, false if not. is_committed_address(const MetaWord * p) const100 bool is_committed_address(const MetaWord* p) const { 101 DEBUG_ONLY(check_pointer(p)); 102 const idx_t bitno = bitno_for_address(p); 103 return at(bitno); 104 } 105 106 // Given an address range, return size, in number of words, of committed area within that range. get_committed_size_in_range(const MetaWord * start,size_t word_size) const107 size_t get_committed_size_in_range(const MetaWord* start, size_t word_size) const { 108 DEBUG_ONLY(check_range(start, word_size)); 109 assert(word_size > 0, "zero range"); 110 const idx_t b1 = bitno_for_address(start); 111 const idx_t b2 = bitno_for_address(start + word_size); 112 const idx_t num_bits = count_one_bits(b1, b2); 113 return num_bits * _words_per_bit; 114 } 115 116 // Return total committed size, in number of words. get_committed_size() const117 size_t get_committed_size() const { 118 return count_one_bits() * _words_per_bit; 119 } 120 121 // Mark a whole address range [start, end) as committed. 122 // Return the number of words which had already been committed before this operation. mark_range_as_committed(const MetaWord * start,size_t word_size)123 size_t mark_range_as_committed(const MetaWord* start, size_t word_size) { 124 DEBUG_ONLY(check_range(start, word_size)); 125 assert(word_size > 0, "zero range"); 126 const idx_t b1 = bitno_for_address(start); 127 const idx_t b2 = bitno_for_address(start + word_size); 128 if (b1 == b2) { // Simple case, 1 granule 129 bool was_committed = mark_granule(b1, true); 130 return was_committed ? _words_per_bit : 0; 131 } 132 const idx_t one_bits_in_range_before = count_one_bits(b1, b2); 133 set_range(b1, b2); 134 return one_bits_in_range_before * _words_per_bit; 135 } 136 137 // Mark a whole address range [start, end) as uncommitted. 138 // Return the number of words which had already been uncommitted before this operation. mark_range_as_uncommitted(const MetaWord * start,size_t word_size)139 size_t mark_range_as_uncommitted(const MetaWord* start, size_t word_size) { 140 DEBUG_ONLY(check_range(start, word_size)); 141 assert(word_size > 0, "zero range"); 142 const idx_t b1 = bitno_for_address(start); 143 const idx_t b2 = bitno_for_address(start + word_size); 144 if (b1 == b2) { // Simple case, 1 granule 145 bool was_committed = mark_granule(b1, false); 146 return was_committed ? 0 : _words_per_bit; 147 } 148 const idx_t zero_bits_in_range_before = 149 (b2 - b1) - count_one_bits(b1, b2); 150 clear_range(b1, b2); 151 return zero_bits_in_range_before * _words_per_bit; 152 } 153 154 //// Debug stuff //// 155 156 // Verify internals. 157 DEBUG_ONLY(void verify() const;) 158 159 void print_on(outputStream* st) const; 160 161 }; 162 163 } // namespace metaspace 164 165 #endif // SHARE_MEMORY_METASPACE_COMMITMASK_HPP 166