342
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1 /*
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2 * Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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4 *
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5 * This code is free software; you can redistribute it and/or modify it
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6 * under the terms of the GNU General Public License version 2 only, as
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7 * published by the Free Software Foundation.
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8 *
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9 * This code is distributed in the hope that it will be useful, but WITHOUT
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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12 * version 2 for more details (a copy is included in the LICENSE file that
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13 * accompanied this code).
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14 *
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15 * You should have received a copy of the GNU General Public License version
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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18 *
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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20 * CA 95054 USA or visit www.sun.com if you need additional information or
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21 * have any questions.
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22 *
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23 */
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24
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25 #include "incls/_precompiled.incl"
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26 #include "incls/_g1BlockOffsetTable.cpp.incl"
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27
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28 //////////////////////////////////////////////////////////////////////
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29 // G1BlockOffsetSharedArray
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30 //////////////////////////////////////////////////////////////////////
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31
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32 G1BlockOffsetSharedArray::G1BlockOffsetSharedArray(MemRegion reserved,
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33 size_t init_word_size) :
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34 _reserved(reserved), _end(NULL)
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35 {
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36 size_t size = compute_size(reserved.word_size());
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37 ReservedSpace rs(ReservedSpace::allocation_align_size_up(size));
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38 if (!rs.is_reserved()) {
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39 vm_exit_during_initialization("Could not reserve enough space for heap offset array");
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40 }
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41 if (!_vs.initialize(rs, 0)) {
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42 vm_exit_during_initialization("Could not reserve enough space for heap offset array");
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43 }
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44 _offset_array = (u_char*)_vs.low_boundary();
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45 resize(init_word_size);
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46 if (TraceBlockOffsetTable) {
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47 gclog_or_tty->print_cr("G1BlockOffsetSharedArray::G1BlockOffsetSharedArray: ");
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48 gclog_or_tty->print_cr(" "
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49 " rs.base(): " INTPTR_FORMAT
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50 " rs.size(): " INTPTR_FORMAT
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51 " rs end(): " INTPTR_FORMAT,
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52 rs.base(), rs.size(), rs.base() + rs.size());
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53 gclog_or_tty->print_cr(" "
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54 " _vs.low_boundary(): " INTPTR_FORMAT
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55 " _vs.high_boundary(): " INTPTR_FORMAT,
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56 _vs.low_boundary(),
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57 _vs.high_boundary());
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58 }
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59 }
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60
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61 void G1BlockOffsetSharedArray::resize(size_t new_word_size) {
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62 assert(new_word_size <= _reserved.word_size(), "Resize larger than reserved");
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63 size_t new_size = compute_size(new_word_size);
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64 size_t old_size = _vs.committed_size();
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65 size_t delta;
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66 char* high = _vs.high();
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67 _end = _reserved.start() + new_word_size;
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68 if (new_size > old_size) {
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69 delta = ReservedSpace::page_align_size_up(new_size - old_size);
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70 assert(delta > 0, "just checking");
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71 if (!_vs.expand_by(delta)) {
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72 // Do better than this for Merlin
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73 vm_exit_out_of_memory(delta, "offset table expansion");
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74 }
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75 assert(_vs.high() == high + delta, "invalid expansion");
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76 // Initialization of the contents is left to the
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77 // G1BlockOffsetArray that uses it.
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78 } else {
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79 delta = ReservedSpace::page_align_size_down(old_size - new_size);
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80 if (delta == 0) return;
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81 _vs.shrink_by(delta);
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82 assert(_vs.high() == high - delta, "invalid expansion");
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83 }
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84 }
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85
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86 bool G1BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const {
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87 assert(p >= _reserved.start(), "just checking");
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88 size_t delta = pointer_delta(p, _reserved.start());
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89 return (delta & right_n_bits(LogN_words)) == (size_t)NoBits;
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90 }
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91
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92
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93 //////////////////////////////////////////////////////////////////////
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94 // G1BlockOffsetArray
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95 //////////////////////////////////////////////////////////////////////
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96
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97 G1BlockOffsetArray::G1BlockOffsetArray(G1BlockOffsetSharedArray* array,
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98 MemRegion mr, bool init_to_zero) :
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99 G1BlockOffsetTable(mr.start(), mr.end()),
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100 _unallocated_block(_bottom),
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101 _array(array), _csp(NULL),
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102 _init_to_zero(init_to_zero) {
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103 assert(_bottom <= _end, "arguments out of order");
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104 if (!_init_to_zero) {
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105 // initialize cards to point back to mr.start()
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106 set_remainder_to_point_to_start(mr.start() + N_words, mr.end());
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107 _array->set_offset_array(0, 0); // set first card to 0
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108 }
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109 }
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110
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111 void G1BlockOffsetArray::set_space(Space* sp) {
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112 _sp = sp;
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113 _csp = sp->toContiguousSpace();
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114 }
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115
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116 // The arguments follow the normal convention of denoting
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117 // a right-open interval: [start, end)
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118 void
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119 G1BlockOffsetArray:: set_remainder_to_point_to_start(HeapWord* start, HeapWord* end) {
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120
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121 if (start >= end) {
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122 // The start address is equal to the end address (or to
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123 // the right of the end address) so there are not cards
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124 // that need to be updated..
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125 return;
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126 }
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127
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128 // Write the backskip value for each region.
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129 //
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130 // offset
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131 // card 2nd 3rd
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132 // | +- 1st | |
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133 // v v v v
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134 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-
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135 // |x|0|0|0|0|0|0|0|1|1|1|1|1|1| ... |1|1|1|1|2|2|2|2|2|2| ...
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136 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-
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137 // 11 19 75
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138 // 12
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139 //
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140 // offset card is the card that points to the start of an object
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141 // x - offset value of offset card
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142 // 1st - start of first logarithmic region
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143 // 0 corresponds to logarithmic value N_words + 0 and 2**(3 * 0) = 1
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144 // 2nd - start of second logarithmic region
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145 // 1 corresponds to logarithmic value N_words + 1 and 2**(3 * 1) = 8
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146 // 3rd - start of third logarithmic region
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147 // 2 corresponds to logarithmic value N_words + 2 and 2**(3 * 2) = 64
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148 //
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149 // integer below the block offset entry is an example of
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150 // the index of the entry
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151 //
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152 // Given an address,
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153 // Find the index for the address
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154 // Find the block offset table entry
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155 // Convert the entry to a back slide
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156 // (e.g., with today's, offset = 0x81 =>
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157 // back slip = 2**(3*(0x81 - N_words)) = 2**3) = 8
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158 // Move back N (e.g., 8) entries and repeat with the
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159 // value of the new entry
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160 //
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161 size_t start_card = _array->index_for(start);
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162 size_t end_card = _array->index_for(end-1);
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163 assert(start ==_array->address_for_index(start_card), "Precondition");
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164 assert(end ==_array->address_for_index(end_card)+N_words, "Precondition");
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165 set_remainder_to_point_to_start_incl(start_card, end_card); // closed interval
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166 }
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167
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168 // Unlike the normal convention in this code, the argument here denotes
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169 // a closed, inclusive interval: [start_card, end_card], cf set_remainder_to_point_to_start()
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170 // above.
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171 void
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172 G1BlockOffsetArray::set_remainder_to_point_to_start_incl(size_t start_card, size_t end_card) {
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173 if (start_card > end_card) {
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174 return;
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175 }
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176 assert(start_card > _array->index_for(_bottom), "Cannot be first card");
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177 assert(_array->offset_array(start_card-1) <= N_words,
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178 "Offset card has an unexpected value");
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179 size_t start_card_for_region = start_card;
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180 u_char offset = max_jubyte;
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181 for (int i = 0; i < BlockOffsetArray::N_powers; i++) {
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182 // -1 so that the the card with the actual offset is counted. Another -1
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183 // so that the reach ends in this region and not at the start
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184 // of the next.
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185 size_t reach = start_card - 1 + (BlockOffsetArray::power_to_cards_back(i+1) - 1);
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186 offset = N_words + i;
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187 if (reach >= end_card) {
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188 _array->set_offset_array(start_card_for_region, end_card, offset);
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189 start_card_for_region = reach + 1;
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190 break;
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191 }
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192 _array->set_offset_array(start_card_for_region, reach, offset);
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193 start_card_for_region = reach + 1;
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194 }
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195 assert(start_card_for_region > end_card, "Sanity check");
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196 DEBUG_ONLY(check_all_cards(start_card, end_card);)
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197 }
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198
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199 // The block [blk_start, blk_end) has been allocated;
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200 // adjust the block offset table to represent this information;
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201 // right-open interval: [blk_start, blk_end)
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202 void
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203 G1BlockOffsetArray::alloc_block(HeapWord* blk_start, HeapWord* blk_end) {
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204 mark_block(blk_start, blk_end);
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205 allocated(blk_start, blk_end);
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206 }
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207
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208 // Adjust BOT to show that a previously whole block has been split
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209 // into two.
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210 void G1BlockOffsetArray::split_block(HeapWord* blk, size_t blk_size,
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211 size_t left_blk_size) {
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212 // Verify that the BOT shows [blk, blk + blk_size) to be one block.
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213 verify_single_block(blk, blk_size);
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214 // Update the BOT to indicate that [blk + left_blk_size, blk + blk_size)
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215 // is one single block.
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216 mark_block(blk + left_blk_size, blk + blk_size);
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217 }
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218
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219
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220 // Action_mark - update the BOT for the block [blk_start, blk_end).
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221 // Current typical use is for splitting a block.
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222 // Action_single - udpate the BOT for an allocation.
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223 // Action_verify - BOT verification.
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224 void G1BlockOffsetArray::do_block_internal(HeapWord* blk_start,
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225 HeapWord* blk_end,
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226 Action action) {
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227 assert(Universe::heap()->is_in_reserved(blk_start),
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228 "reference must be into the heap");
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229 assert(Universe::heap()->is_in_reserved(blk_end-1),
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230 "limit must be within the heap");
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231 // This is optimized to make the test fast, assuming we only rarely
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232 // cross boundaries.
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233 uintptr_t end_ui = (uintptr_t)(blk_end - 1);
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234 uintptr_t start_ui = (uintptr_t)blk_start;
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235 // Calculate the last card boundary preceding end of blk
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236 intptr_t boundary_before_end = (intptr_t)end_ui;
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237 clear_bits(boundary_before_end, right_n_bits(LogN));
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238 if (start_ui <= (uintptr_t)boundary_before_end) {
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239 // blk starts at or crosses a boundary
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240 // Calculate index of card on which blk begins
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241 size_t start_index = _array->index_for(blk_start);
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242 // Index of card on which blk ends
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243 size_t end_index = _array->index_for(blk_end - 1);
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244 // Start address of card on which blk begins
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245 HeapWord* boundary = _array->address_for_index(start_index);
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246 assert(boundary <= blk_start, "blk should start at or after boundary");
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247 if (blk_start != boundary) {
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248 // blk starts strictly after boundary
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249 // adjust card boundary and start_index forward to next card
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250 boundary += N_words;
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251 start_index++;
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252 }
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253 assert(start_index <= end_index, "monotonicity of index_for()");
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254 assert(boundary <= (HeapWord*)boundary_before_end, "tautology");
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255 switch (action) {
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256 case Action_mark: {
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257 if (init_to_zero()) {
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258 _array->set_offset_array(start_index, boundary, blk_start);
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259 break;
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260 } // Else fall through to the next case
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261 }
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262 case Action_single: {
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263 _array->set_offset_array(start_index, boundary, blk_start);
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264 // We have finished marking the "offset card". We need to now
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265 // mark the subsequent cards that this blk spans.
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266 if (start_index < end_index) {
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267 HeapWord* rem_st = _array->address_for_index(start_index) + N_words;
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268 HeapWord* rem_end = _array->address_for_index(end_index) + N_words;
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269 set_remainder_to_point_to_start(rem_st, rem_end);
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270 }
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271 break;
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272 }
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273 case Action_check: {
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274 _array->check_offset_array(start_index, boundary, blk_start);
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275 // We have finished checking the "offset card". We need to now
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276 // check the subsequent cards that this blk spans.
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277 check_all_cards(start_index + 1, end_index);
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278 break;
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279 }
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280 default:
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281 ShouldNotReachHere();
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282 }
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283 }
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284 }
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285
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286 // The card-interval [start_card, end_card] is a closed interval; this
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287 // is an expensive check -- use with care and only under protection of
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288 // suitable flag.
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289 void G1BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const {
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290
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291 if (end_card < start_card) {
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292 return;
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293 }
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294 guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card");
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295 for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) {
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296 u_char entry = _array->offset_array(c);
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297 if (c - start_card > BlockOffsetArray::power_to_cards_back(1)) {
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298 guarantee(entry > N_words, "Should be in logarithmic region");
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299 }
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300 size_t backskip = BlockOffsetArray::entry_to_cards_back(entry);
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301 size_t landing_card = c - backskip;
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302 guarantee(landing_card >= (start_card - 1), "Inv");
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303 if (landing_card >= start_card) {
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304 guarantee(_array->offset_array(landing_card) <= entry, "monotonicity");
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305 } else {
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306 guarantee(landing_card == start_card - 1, "Tautology");
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307 guarantee(_array->offset_array(landing_card) <= N_words, "Offset value");
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308 }
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309 }
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310 }
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311
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312 // The range [blk_start, blk_end) represents a single contiguous block
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313 // of storage; modify the block offset table to represent this
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314 // information; Right-open interval: [blk_start, blk_end)
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315 // NOTE: this method does _not_ adjust _unallocated_block.
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316 void
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317 G1BlockOffsetArray::single_block(HeapWord* blk_start, HeapWord* blk_end) {
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318 do_block_internal(blk_start, blk_end, Action_single);
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319 }
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320
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321 // Mark the BOT such that if [blk_start, blk_end) straddles a card
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322 // boundary, the card following the first such boundary is marked
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323 // with the appropriate offset.
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324 // NOTE: this method does _not_ adjust _unallocated_block or
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325 // any cards subsequent to the first one.
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326 void
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327 G1BlockOffsetArray::mark_block(HeapWord* blk_start, HeapWord* blk_end) {
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328 do_block_internal(blk_start, blk_end, Action_mark);
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329 }
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330
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331 void G1BlockOffsetArray::join_blocks(HeapWord* blk1, HeapWord* blk2) {
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332 HeapWord* blk1_start = Universe::heap()->block_start(blk1);
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333 HeapWord* blk2_start = Universe::heap()->block_start(blk2);
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334 assert(blk1 == blk1_start && blk2 == blk2_start,
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335 "Must be block starts.");
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336 assert(blk1 + _sp->block_size(blk1) == blk2, "Must be contiguous.");
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337 size_t blk1_start_index = _array->index_for(blk1);
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338 size_t blk2_start_index = _array->index_for(blk2);
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339 assert(blk1_start_index <= blk2_start_index, "sanity");
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340 HeapWord* blk2_card_start = _array->address_for_index(blk2_start_index);
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341 if (blk2 == blk2_card_start) {
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342 // blk2 starts a card. Does blk1 start on the prevous card, or futher
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343 // back?
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344 assert(blk1_start_index < blk2_start_index, "must be lower card.");
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345 if (blk1_start_index + 1 == blk2_start_index) {
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346 // previous card; new value for blk2 card is size of blk1.
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347 _array->set_offset_array(blk2_start_index, (u_char) _sp->block_size(blk1));
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348 } else {
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349 // Earlier card; go back a card.
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350 _array->set_offset_array(blk2_start_index, N_words);
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351 }
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352 } else {
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353 // blk2 does not start a card. Does it cross a card? If not, nothing
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354 // to do.
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355 size_t blk2_end_index =
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356 _array->index_for(blk2 + _sp->block_size(blk2) - 1);
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357 assert(blk2_end_index >= blk2_start_index, "sanity");
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358 if (blk2_end_index > blk2_start_index) {
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359 // Yes, it crosses a card. The value for the next card must change.
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360 if (blk1_start_index + 1 == blk2_start_index) {
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361 // previous card; new value for second blk2 card is size of blk1.
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362 _array->set_offset_array(blk2_start_index + 1,
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363 (u_char) _sp->block_size(blk1));
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364 } else {
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365 // Earlier card; go back a card.
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366 _array->set_offset_array(blk2_start_index + 1, N_words);
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367 }
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368 }
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369 }
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370 }
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371
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372 HeapWord* G1BlockOffsetArray::block_start_unsafe(const void* addr) {
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373 assert(_bottom <= addr && addr < _end,
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374 "addr must be covered by this Array");
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375 // Must read this exactly once because it can be modified by parallel
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376 // allocation.
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377 HeapWord* ub = _unallocated_block;
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378 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
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379 assert(ub < _end, "tautology (see above)");
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380 return ub;
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381 }
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382 // Otherwise, find the block start using the table.
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383 HeapWord* q = block_at_or_preceding(addr, false, 0);
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384 return forward_to_block_containing_addr(q, addr);
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385 }
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386
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387 // This duplicates a little code from the above: unavoidable.
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388 HeapWord*
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389 G1BlockOffsetArray::block_start_unsafe_const(const void* addr) const {
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390 assert(_bottom <= addr && addr < _end,
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391 "addr must be covered by this Array");
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392 // Must read this exactly once because it can be modified by parallel
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393 // allocation.
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394 HeapWord* ub = _unallocated_block;
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395 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
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396 assert(ub < _end, "tautology (see above)");
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397 return ub;
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398 }
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399 // Otherwise, find the block start using the table.
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400 HeapWord* q = block_at_or_preceding(addr, false, 0);
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401 HeapWord* n = q + _sp->block_size(q);
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402 return forward_to_block_containing_addr_const(q, n, addr);
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|
403 }
|
|
404
|
|
405
|
|
406 HeapWord*
|
|
407 G1BlockOffsetArray::forward_to_block_containing_addr_slow(HeapWord* q,
|
|
408 HeapWord* n,
|
|
409 const void* addr) {
|
|
410 // We're not in the normal case. We need to handle an important subcase
|
|
411 // here: LAB allocation. An allocation previously recorded in the
|
|
412 // offset table was actually a lab allocation, and was divided into
|
|
413 // several objects subsequently. Fix this situation as we answer the
|
|
414 // query, by updating entries as we cross them.
|
|
415 size_t next_index = _array->index_for(n) + 1;
|
|
416 HeapWord* next_boundary = _array->address_for_index(next_index);
|
|
417 if (csp() != NULL) {
|
|
418 if (addr >= csp()->top()) return csp()->top();
|
|
419 while (next_boundary < addr) {
|
|
420 while (n <= next_boundary) {
|
|
421 q = n;
|
|
422 oop obj = oop(q);
|
|
423 if (obj->klass() == NULL) return q;
|
|
424 n += obj->size();
|
|
425 }
|
|
426 assert(q <= next_boundary && n > next_boundary, "Consequence of loop");
|
|
427 // [q, n) is the block that crosses the boundary.
|
|
428 alloc_block_work2(&next_boundary, &next_index, q, n);
|
|
429 }
|
|
430 } else {
|
|
431 while (next_boundary < addr) {
|
|
432 while (n <= next_boundary) {
|
|
433 q = n;
|
|
434 oop obj = oop(q);
|
|
435 if (obj->klass() == NULL) return q;
|
|
436 n += _sp->block_size(q);
|
|
437 }
|
|
438 assert(q <= next_boundary && n > next_boundary, "Consequence of loop");
|
|
439 // [q, n) is the block that crosses the boundary.
|
|
440 alloc_block_work2(&next_boundary, &next_index, q, n);
|
|
441 }
|
|
442 }
|
|
443 return forward_to_block_containing_addr_const(q, n, addr);
|
|
444 }
|
|
445
|
|
446 HeapWord* G1BlockOffsetArray::block_start_careful(const void* addr) const {
|
|
447 assert(_array->offset_array(0) == 0, "objects can't cross covered areas");
|
|
448
|
|
449 assert(_bottom <= addr && addr < _end,
|
|
450 "addr must be covered by this Array");
|
|
451 // Must read this exactly once because it can be modified by parallel
|
|
452 // allocation.
|
|
453 HeapWord* ub = _unallocated_block;
|
|
454 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
|
|
455 assert(ub < _end, "tautology (see above)");
|
|
456 return ub;
|
|
457 }
|
|
458
|
|
459 // Otherwise, find the block start using the table, but taking
|
|
460 // care (cf block_start_unsafe() above) not to parse any objects/blocks
|
|
461 // on the cards themsleves.
|
|
462 size_t index = _array->index_for(addr);
|
|
463 assert(_array->address_for_index(index) == addr,
|
|
464 "arg should be start of card");
|
|
465
|
|
466 HeapWord* q = (HeapWord*)addr;
|
|
467 uint offset;
|
|
468 do {
|
|
469 offset = _array->offset_array(index--);
|
|
470 q -= offset;
|
|
471 } while (offset == N_words);
|
|
472 assert(q <= addr, "block start should be to left of arg");
|
|
473 return q;
|
|
474 }
|
|
475
|
|
476 // Note that the committed size of the covered space may have changed,
|
|
477 // so the table size might also wish to change.
|
|
478 void G1BlockOffsetArray::resize(size_t new_word_size) {
|
|
479 HeapWord* new_end = _bottom + new_word_size;
|
|
480 if (_end < new_end && !init_to_zero()) {
|
|
481 // verify that the old and new boundaries are also card boundaries
|
|
482 assert(_array->is_card_boundary(_end),
|
|
483 "_end not a card boundary");
|
|
484 assert(_array->is_card_boundary(new_end),
|
|
485 "new _end would not be a card boundary");
|
|
486 // set all the newly added cards
|
|
487 _array->set_offset_array(_end, new_end, N_words);
|
|
488 }
|
|
489 _end = new_end; // update _end
|
|
490 }
|
|
491
|
|
492 void G1BlockOffsetArray::set_region(MemRegion mr) {
|
|
493 _bottom = mr.start();
|
|
494 _end = mr.end();
|
|
495 }
|
|
496
|
|
497 //
|
|
498 // threshold_
|
|
499 // | _index_
|
|
500 // v v
|
|
501 // +-------+-------+-------+-------+-------+
|
|
502 // | i-1 | i | i+1 | i+2 | i+3 |
|
|
503 // +-------+-------+-------+-------+-------+
|
|
504 // ( ^ ]
|
|
505 // block-start
|
|
506 //
|
|
507 void G1BlockOffsetArray::alloc_block_work2(HeapWord** threshold_, size_t* index_,
|
|
508 HeapWord* blk_start, HeapWord* blk_end) {
|
|
509 // For efficiency, do copy-in/copy-out.
|
|
510 HeapWord* threshold = *threshold_;
|
|
511 size_t index = *index_;
|
|
512
|
|
513 assert(blk_start != NULL && blk_end > blk_start,
|
|
514 "phantom block");
|
|
515 assert(blk_end > threshold, "should be past threshold");
|
|
516 assert(blk_start <= threshold, "blk_start should be at or before threshold")
|
|
517 assert(pointer_delta(threshold, blk_start) <= N_words,
|
|
518 "offset should be <= BlockOffsetSharedArray::N");
|
|
519 assert(Universe::heap()->is_in_reserved(blk_start),
|
|
520 "reference must be into the heap");
|
|
521 assert(Universe::heap()->is_in_reserved(blk_end-1),
|
|
522 "limit must be within the heap");
|
|
523 assert(threshold == _array->_reserved.start() + index*N_words,
|
|
524 "index must agree with threshold");
|
|
525
|
|
526 DEBUG_ONLY(size_t orig_index = index;)
|
|
527
|
|
528 // Mark the card that holds the offset into the block. Note
|
|
529 // that _next_offset_index and _next_offset_threshold are not
|
|
530 // updated until the end of this method.
|
|
531 _array->set_offset_array(index, threshold, blk_start);
|
|
532
|
|
533 // We need to now mark the subsequent cards that this blk spans.
|
|
534
|
|
535 // Index of card on which blk ends.
|
|
536 size_t end_index = _array->index_for(blk_end - 1);
|
|
537
|
|
538 // Are there more cards left to be updated?
|
|
539 if (index + 1 <= end_index) {
|
|
540 HeapWord* rem_st = _array->address_for_index(index + 1);
|
|
541 // Calculate rem_end this way because end_index
|
|
542 // may be the last valid index in the covered region.
|
|
543 HeapWord* rem_end = _array->address_for_index(end_index) + N_words;
|
|
544 set_remainder_to_point_to_start(rem_st, rem_end);
|
|
545 }
|
|
546
|
|
547 index = end_index + 1;
|
|
548 // Calculate threshold_ this way because end_index
|
|
549 // may be the last valid index in the covered region.
|
|
550 threshold = _array->address_for_index(end_index) + N_words;
|
|
551 assert(threshold >= blk_end, "Incorrect offset threshold");
|
|
552
|
|
553 // index_ and threshold_ updated here.
|
|
554 *threshold_ = threshold;
|
|
555 *index_ = index;
|
|
556
|
|
557 #ifdef ASSERT
|
|
558 // The offset can be 0 if the block starts on a boundary. That
|
|
559 // is checked by an assertion above.
|
|
560 size_t start_index = _array->index_for(blk_start);
|
|
561 HeapWord* boundary = _array->address_for_index(start_index);
|
|
562 assert((_array->offset_array(orig_index) == 0 &&
|
|
563 blk_start == boundary) ||
|
|
564 (_array->offset_array(orig_index) > 0 &&
|
|
565 _array->offset_array(orig_index) <= N_words),
|
|
566 "offset array should have been set");
|
|
567 for (size_t j = orig_index + 1; j <= end_index; j++) {
|
|
568 assert(_array->offset_array(j) > 0 &&
|
|
569 _array->offset_array(j) <=
|
|
570 (u_char) (N_words+BlockOffsetArray::N_powers-1),
|
|
571 "offset array should have been set");
|
|
572 }
|
|
573 #endif
|
|
574 }
|
|
575
|
|
576 //////////////////////////////////////////////////////////////////////
|
|
577 // G1BlockOffsetArrayContigSpace
|
|
578 //////////////////////////////////////////////////////////////////////
|
|
579
|
|
580 HeapWord*
|
|
581 G1BlockOffsetArrayContigSpace::block_start_unsafe(const void* addr) {
|
|
582 assert(_bottom <= addr && addr < _end,
|
|
583 "addr must be covered by this Array");
|
|
584 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
|
|
585 return forward_to_block_containing_addr(q, addr);
|
|
586 }
|
|
587
|
|
588 HeapWord*
|
|
589 G1BlockOffsetArrayContigSpace::
|
|
590 block_start_unsafe_const(const void* addr) const {
|
|
591 assert(_bottom <= addr && addr < _end,
|
|
592 "addr must be covered by this Array");
|
|
593 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
|
|
594 HeapWord* n = q + _sp->block_size(q);
|
|
595 return forward_to_block_containing_addr_const(q, n, addr);
|
|
596 }
|
|
597
|
|
598 G1BlockOffsetArrayContigSpace::
|
|
599 G1BlockOffsetArrayContigSpace(G1BlockOffsetSharedArray* array,
|
|
600 MemRegion mr) :
|
|
601 G1BlockOffsetArray(array, mr, true)
|
|
602 {
|
|
603 _next_offset_threshold = NULL;
|
|
604 _next_offset_index = 0;
|
|
605 }
|
|
606
|
|
607 HeapWord* G1BlockOffsetArrayContigSpace::initialize_threshold() {
|
|
608 assert(!Universe::heap()->is_in_reserved(_array->_offset_array),
|
|
609 "just checking");
|
|
610 _next_offset_index = _array->index_for(_bottom);
|
|
611 _next_offset_index++;
|
|
612 _next_offset_threshold =
|
|
613 _array->address_for_index(_next_offset_index);
|
|
614 return _next_offset_threshold;
|
|
615 }
|
|
616
|
|
617 void G1BlockOffsetArrayContigSpace::zero_bottom_entry() {
|
|
618 assert(!Universe::heap()->is_in_reserved(_array->_offset_array),
|
|
619 "just checking");
|
|
620 size_t bottom_index = _array->index_for(_bottom);
|
|
621 assert(_array->address_for_index(bottom_index) == _bottom,
|
|
622 "Precondition of call");
|
|
623 _array->set_offset_array(bottom_index, 0);
|
|
624 }
|