0
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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/_parallelScavengeHeap.cpp.incl"
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27
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28 PSYoungGen* ParallelScavengeHeap::_young_gen = NULL;
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29 PSOldGen* ParallelScavengeHeap::_old_gen = NULL;
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30 PSPermGen* ParallelScavengeHeap::_perm_gen = NULL;
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31 PSAdaptiveSizePolicy* ParallelScavengeHeap::_size_policy = NULL;
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32 PSGCAdaptivePolicyCounters* ParallelScavengeHeap::_gc_policy_counters = NULL;
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33 ParallelScavengeHeap* ParallelScavengeHeap::_psh = NULL;
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34 GCTaskManager* ParallelScavengeHeap::_gc_task_manager = NULL;
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35
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36 static void trace_gen_sizes(const char* const str,
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37 size_t pg_min, size_t pg_max,
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38 size_t og_min, size_t og_max,
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39 size_t yg_min, size_t yg_max)
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40 {
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41 if (TracePageSizes) {
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42 tty->print_cr("%s: " SIZE_FORMAT "," SIZE_FORMAT " "
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43 SIZE_FORMAT "," SIZE_FORMAT " "
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44 SIZE_FORMAT "," SIZE_FORMAT " "
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45 SIZE_FORMAT,
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46 str, pg_min / K, pg_max / K,
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47 og_min / K, og_max / K,
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48 yg_min / K, yg_max / K,
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49 (pg_max + og_max + yg_max) / K);
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50 }
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51 }
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52
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53 jint ParallelScavengeHeap::initialize() {
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54 // Cannot be initialized until after the flags are parsed
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55 GenerationSizer flag_parser;
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56
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57 size_t yg_min_size = flag_parser.min_young_gen_size();
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58 size_t yg_max_size = flag_parser.max_young_gen_size();
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59 size_t og_min_size = flag_parser.min_old_gen_size();
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60 size_t og_max_size = flag_parser.max_old_gen_size();
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61 // Why isn't there a min_perm_gen_size()?
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62 size_t pg_min_size = flag_parser.perm_gen_size();
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63 size_t pg_max_size = flag_parser.max_perm_gen_size();
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64
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65 trace_gen_sizes("ps heap raw",
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66 pg_min_size, pg_max_size,
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67 og_min_size, og_max_size,
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68 yg_min_size, yg_max_size);
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69
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70 // The ReservedSpace ctor used below requires that the page size for the perm
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71 // gen is <= the page size for the rest of the heap (young + old gens).
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72 const size_t og_page_sz = os::page_size_for_region(yg_min_size + og_min_size,
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73 yg_max_size + og_max_size,
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74 8);
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75 const size_t pg_page_sz = MIN2(os::page_size_for_region(pg_min_size,
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76 pg_max_size, 16),
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77 og_page_sz);
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78
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79 const size_t pg_align = set_alignment(_perm_gen_alignment, pg_page_sz);
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80 const size_t og_align = set_alignment(_old_gen_alignment, og_page_sz);
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81 const size_t yg_align = set_alignment(_young_gen_alignment, og_page_sz);
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82
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83 // Update sizes to reflect the selected page size(s).
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84 //
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85 // NEEDS_CLEANUP. The default TwoGenerationCollectorPolicy uses NewRatio; it
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86 // should check UseAdaptiveSizePolicy. Changes from generationSizer could
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87 // move to the common code.
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88 yg_min_size = align_size_up(yg_min_size, yg_align);
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89 yg_max_size = align_size_up(yg_max_size, yg_align);
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90 size_t yg_cur_size = align_size_up(flag_parser.young_gen_size(), yg_align);
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91 yg_cur_size = MAX2(yg_cur_size, yg_min_size);
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92
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93 og_min_size = align_size_up(og_min_size, og_align);
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94 og_max_size = align_size_up(og_max_size, og_align);
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95 size_t og_cur_size = align_size_up(flag_parser.old_gen_size(), og_align);
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96 og_cur_size = MAX2(og_cur_size, og_min_size);
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97
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98 pg_min_size = align_size_up(pg_min_size, pg_align);
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99 pg_max_size = align_size_up(pg_max_size, pg_align);
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100 size_t pg_cur_size = pg_min_size;
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101
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102 trace_gen_sizes("ps heap rnd",
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103 pg_min_size, pg_max_size,
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104 og_min_size, og_max_size,
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105 yg_min_size, yg_max_size);
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106
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107 // The main part of the heap (old gen + young gen) can often use a larger page
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108 // size than is needed or wanted for the perm gen. Use the "compound
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109 // alignment" ReservedSpace ctor to avoid having to use the same page size for
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110 // all gens.
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111 ReservedSpace heap_rs(pg_max_size, pg_align, og_max_size + yg_max_size,
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112 og_align);
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113 os::trace_page_sizes("ps perm", pg_min_size, pg_max_size, pg_page_sz,
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114 heap_rs.base(), pg_max_size);
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115 os::trace_page_sizes("ps main", og_min_size + yg_min_size,
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116 og_max_size + yg_max_size, og_page_sz,
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117 heap_rs.base() + pg_max_size,
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118 heap_rs.size() - pg_max_size);
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119 if (!heap_rs.is_reserved()) {
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120 vm_shutdown_during_initialization(
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121 "Could not reserve enough space for object heap");
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122 return JNI_ENOMEM;
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123 }
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124
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125 _reserved = MemRegion((HeapWord*)heap_rs.base(),
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126 (HeapWord*)(heap_rs.base() + heap_rs.size()));
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127
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128 CardTableExtension* const barrier_set = new CardTableExtension(_reserved, 3);
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129 _barrier_set = barrier_set;
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130 oopDesc::set_bs(_barrier_set);
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131 if (_barrier_set == NULL) {
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132 vm_shutdown_during_initialization(
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133 "Could not reserve enough space for barrier set");
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134 return JNI_ENOMEM;
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135 }
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136
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137 // Initial young gen size is 4 Mb
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138 //
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139 // XXX - what about flag_parser.young_gen_size()?
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140 const size_t init_young_size = align_size_up(4 * M, yg_align);
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141 yg_cur_size = MAX2(MIN2(init_young_size, yg_max_size), yg_cur_size);
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142
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143 // Split the reserved space into perm gen and the main heap (everything else).
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144 // The main heap uses a different alignment.
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145 ReservedSpace perm_rs = heap_rs.first_part(pg_max_size);
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146 ReservedSpace main_rs = heap_rs.last_part(pg_max_size, og_align);
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147
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148 // Make up the generations
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149 // Calculate the maximum size that a generation can grow. This
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150 // includes growth into the other generation. Note that the
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151 // parameter _max_gen_size is kept as the maximum
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152 // size of the generation as the boundaries currently stand.
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153 // _max_gen_size is still used as that value.
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154 double max_gc_pause_sec = ((double) MaxGCPauseMillis)/1000.0;
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155 double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0;
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156
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157 _gens = new AdjoiningGenerations(main_rs,
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158 og_cur_size,
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159 og_min_size,
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160 og_max_size,
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161 yg_cur_size,
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162 yg_min_size,
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163 yg_max_size,
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164 yg_align);
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165
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166 _old_gen = _gens->old_gen();
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167 _young_gen = _gens->young_gen();
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168
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169 const size_t eden_capacity = _young_gen->eden_space()->capacity_in_bytes();
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170 const size_t old_capacity = _old_gen->capacity_in_bytes();
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171 const size_t initial_promo_size = MIN2(eden_capacity, old_capacity);
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172 _size_policy =
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173 new PSAdaptiveSizePolicy(eden_capacity,
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174 initial_promo_size,
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175 young_gen()->to_space()->capacity_in_bytes(),
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176 intra_generation_alignment(),
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177 max_gc_pause_sec,
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178 max_gc_minor_pause_sec,
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179 GCTimeRatio
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180 );
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181
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182 _perm_gen = new PSPermGen(perm_rs,
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183 pg_align,
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184 pg_cur_size,
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185 pg_cur_size,
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186 pg_max_size,
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187 "perm", 2);
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188
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189 assert(!UseAdaptiveGCBoundary ||
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190 (old_gen()->virtual_space()->high_boundary() ==
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191 young_gen()->virtual_space()->low_boundary()),
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192 "Boundaries must meet");
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193 // initialize the policy counters - 2 collectors, 3 generations
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194 _gc_policy_counters =
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195 new PSGCAdaptivePolicyCounters("ParScav:MSC", 2, 3, _size_policy);
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196 _psh = this;
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197
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198 // Set up the GCTaskManager
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199 _gc_task_manager = GCTaskManager::create(ParallelGCThreads);
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200
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201 if (UseParallelOldGC && !PSParallelCompact::initialize()) {
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202 return JNI_ENOMEM;
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203 }
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204
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205 return JNI_OK;
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206 }
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207
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208 void ParallelScavengeHeap::post_initialize() {
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209 // Need to init the tenuring threshold
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210 PSScavenge::initialize();
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211 if (UseParallelOldGC) {
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212 PSParallelCompact::post_initialize();
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213 if (VerifyParallelOldWithMarkSweep) {
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214 // Will be used for verification of par old.
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215 PSMarkSweep::initialize();
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216 }
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217 } else {
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218 PSMarkSweep::initialize();
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219 }
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220 PSPromotionManager::initialize();
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221 }
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222
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223 void ParallelScavengeHeap::update_counters() {
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224 young_gen()->update_counters();
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225 old_gen()->update_counters();
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226 perm_gen()->update_counters();
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227 }
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228
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229 size_t ParallelScavengeHeap::capacity() const {
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230 size_t value = young_gen()->capacity_in_bytes() + old_gen()->capacity_in_bytes();
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231 return value;
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232 }
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233
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234 size_t ParallelScavengeHeap::used() const {
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235 size_t value = young_gen()->used_in_bytes() + old_gen()->used_in_bytes();
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236 return value;
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237 }
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238
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239 bool ParallelScavengeHeap::is_maximal_no_gc() const {
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240 return old_gen()->is_maximal_no_gc() && young_gen()->is_maximal_no_gc();
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241 }
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242
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243
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244 size_t ParallelScavengeHeap::permanent_capacity() const {
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245 return perm_gen()->capacity_in_bytes();
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246 }
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247
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248 size_t ParallelScavengeHeap::permanent_used() const {
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249 return perm_gen()->used_in_bytes();
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250 }
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251
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252 size_t ParallelScavengeHeap::max_capacity() const {
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253 size_t estimated = reserved_region().byte_size();
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254 estimated -= perm_gen()->reserved().byte_size();
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255 if (UseAdaptiveSizePolicy) {
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256 estimated -= _size_policy->max_survivor_size(young_gen()->max_size());
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257 } else {
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258 estimated -= young_gen()->to_space()->capacity_in_bytes();
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259 }
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260 return MAX2(estimated, capacity());
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261 }
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262
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263 bool ParallelScavengeHeap::is_in(const void* p) const {
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264 if (young_gen()->is_in(p)) {
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265 return true;
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266 }
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267
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268 if (old_gen()->is_in(p)) {
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269 return true;
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270 }
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271
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272 if (perm_gen()->is_in(p)) {
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273 return true;
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274 }
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275
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276 return false;
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277 }
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278
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279 bool ParallelScavengeHeap::is_in_reserved(const void* p) const {
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280 if (young_gen()->is_in_reserved(p)) {
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281 return true;
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282 }
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283
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284 if (old_gen()->is_in_reserved(p)) {
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285 return true;
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286 }
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287
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288 if (perm_gen()->is_in_reserved(p)) {
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289 return true;
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290 }
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291
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292 return false;
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293 }
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294
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295 // Static method
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296 bool ParallelScavengeHeap::is_in_young(oop* p) {
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297 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
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298 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap,
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299 "Must be ParallelScavengeHeap");
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300
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301 PSYoungGen* young_gen = heap->young_gen();
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302
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303 if (young_gen->is_in_reserved(p)) {
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304 return true;
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305 }
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306
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307 return false;
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308 }
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309
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310 // Static method
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311 bool ParallelScavengeHeap::is_in_old_or_perm(oop* p) {
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312 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
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313 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap,
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314 "Must be ParallelScavengeHeap");
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315
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316 PSOldGen* old_gen = heap->old_gen();
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317 PSPermGen* perm_gen = heap->perm_gen();
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318
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319 if (old_gen->is_in_reserved(p)) {
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320 return true;
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321 }
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322
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323 if (perm_gen->is_in_reserved(p)) {
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324 return true;
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325 }
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326
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327 return false;
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328 }
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329
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330 // There are two levels of allocation policy here.
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331 //
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332 // When an allocation request fails, the requesting thread must invoke a VM
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333 // operation, transfer control to the VM thread, and await the results of a
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334 // garbage collection. That is quite expensive, and we should avoid doing it
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335 // multiple times if possible.
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336 //
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337 // To accomplish this, we have a basic allocation policy, and also a
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338 // failed allocation policy.
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339 //
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340 // The basic allocation policy controls how you allocate memory without
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341 // attempting garbage collection. It is okay to grab locks and
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342 // expand the heap, if that can be done without coming to a safepoint.
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343 // It is likely that the basic allocation policy will not be very
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344 // aggressive.
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345 //
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346 // The failed allocation policy is invoked from the VM thread after
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347 // the basic allocation policy is unable to satisfy a mem_allocate
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348 // request. This policy needs to cover the entire range of collection,
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349 // heap expansion, and out-of-memory conditions. It should make every
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350 // attempt to allocate the requested memory.
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351
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352 // Basic allocation policy. Should never be called at a safepoint, or
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353 // from the VM thread.
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354 //
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355 // This method must handle cases where many mem_allocate requests fail
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356 // simultaneously. When that happens, only one VM operation will succeed,
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357 // and the rest will not be executed. For that reason, this method loops
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358 // during failed allocation attempts. If the java heap becomes exhausted,
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359 // we rely on the size_policy object to force a bail out.
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360 HeapWord* ParallelScavengeHeap::mem_allocate(
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361 size_t size,
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362 bool is_noref,
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363 bool is_tlab,
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364 bool* gc_overhead_limit_was_exceeded) {
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365 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
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366 assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
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367 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
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368
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369 HeapWord* result = young_gen()->allocate(size, is_tlab);
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370
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371 uint loop_count = 0;
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372 uint gc_count = 0;
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373
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374 while (result == NULL) {
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375 // We don't want to have multiple collections for a single filled generation.
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376 // To prevent this, each thread tracks the total_collections() value, and if
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377 // the count has changed, does not do a new collection.
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378 //
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379 // The collection count must be read only while holding the heap lock. VM
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380 // operations also hold the heap lock during collections. There is a lock
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381 // contention case where thread A blocks waiting on the Heap_lock, while
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382 // thread B is holding it doing a collection. When thread A gets the lock,
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383 // the collection count has already changed. To prevent duplicate collections,
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384 // The policy MUST attempt allocations during the same period it reads the
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385 // total_collections() value!
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386 {
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387 MutexLocker ml(Heap_lock);
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388 gc_count = Universe::heap()->total_collections();
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389
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390 result = young_gen()->allocate(size, is_tlab);
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391
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392 // (1) If the requested object is too large to easily fit in the
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393 // young_gen, or
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394 // (2) If GC is locked out via GCLocker, young gen is full and
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395 // the need for a GC already signalled to GCLocker (done
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396 // at a safepoint),
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397 // ... then, rather than force a safepoint and (a potentially futile)
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398 // collection (attempt) for each allocation, try allocation directly
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399 // in old_gen. For case (2) above, we may in the future allow
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400 // TLAB allocation directly in the old gen.
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401 if (result != NULL) {
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402 return result;
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403 }
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404 if (!is_tlab &&
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405 size >= (young_gen()->eden_space()->capacity_in_words() / 2)) {
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406 result = old_gen()->allocate(size, is_tlab);
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407 if (result != NULL) {
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408 return result;
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409 }
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410 }
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411 if (GC_locker::is_active_and_needs_gc()) {
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412 // GC is locked out. If this is a TLAB allocation,
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413 // return NULL; the requestor will retry allocation
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414 // of an idividual object at a time.
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415 if (is_tlab) {
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416 return NULL;
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417 }
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418
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419 // If this thread is not in a jni critical section, we stall
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420 // the requestor until the critical section has cleared and
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421 // GC allowed. When the critical section clears, a GC is
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422 // initiated by the last thread exiting the critical section; so
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423 // we retry the allocation sequence from the beginning of the loop,
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424 // rather than causing more, now probably unnecessary, GC attempts.
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425 JavaThread* jthr = JavaThread::current();
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426 if (!jthr->in_critical()) {
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427 MutexUnlocker mul(Heap_lock);
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428 GC_locker::stall_until_clear();
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429 continue;
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430 } else {
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431 if (CheckJNICalls) {
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|
432 fatal("Possible deadlock due to allocating while"
|
|
433 " in jni critical section");
|
|
434 }
|
|
435 return NULL;
|
|
436 }
|
|
437 }
|
|
438 }
|
|
439
|
|
440 if (result == NULL) {
|
|
441
|
|
442 // Exit the loop if if the gc time limit has been exceeded.
|
|
443 // The allocation must have failed above (result must be NULL),
|
|
444 // and the most recent collection must have exceeded the
|
|
445 // gc time limit. Exit the loop so that an out-of-memory
|
|
446 // will be thrown (returning a NULL will do that), but
|
|
447 // clear gc_time_limit_exceeded so that the next collection
|
|
448 // will succeeded if the applications decides to handle the
|
|
449 // out-of-memory and tries to go on.
|
|
450 *gc_overhead_limit_was_exceeded = size_policy()->gc_time_limit_exceeded();
|
|
451 if (size_policy()->gc_time_limit_exceeded()) {
|
|
452 size_policy()->set_gc_time_limit_exceeded(false);
|
|
453 if (PrintGCDetails && Verbose) {
|
|
454 gclog_or_tty->print_cr("ParallelScavengeHeap::mem_allocate: "
|
|
455 "return NULL because gc_time_limit_exceeded is set");
|
|
456 }
|
|
457 return NULL;
|
|
458 }
|
|
459
|
|
460 // Generate a VM operation
|
|
461 VM_ParallelGCFailedAllocation op(size, is_tlab, gc_count);
|
|
462 VMThread::execute(&op);
|
|
463
|
|
464 // Did the VM operation execute? If so, return the result directly.
|
|
465 // This prevents us from looping until time out on requests that can
|
|
466 // not be satisfied.
|
|
467 if (op.prologue_succeeded()) {
|
|
468 assert(Universe::heap()->is_in_or_null(op.result()),
|
|
469 "result not in heap");
|
|
470
|
|
471 // If GC was locked out during VM operation then retry allocation
|
|
472 // and/or stall as necessary.
|
|
473 if (op.gc_locked()) {
|
|
474 assert(op.result() == NULL, "must be NULL if gc_locked() is true");
|
|
475 continue; // retry and/or stall as necessary
|
|
476 }
|
|
477 // If a NULL result is being returned, an out-of-memory
|
|
478 // will be thrown now. Clear the gc_time_limit_exceeded
|
|
479 // flag to avoid the following situation.
|
|
480 // gc_time_limit_exceeded is set during a collection
|
|
481 // the collection fails to return enough space and an OOM is thrown
|
|
482 // the next GC is skipped because the gc_time_limit_exceeded
|
|
483 // flag is set and another OOM is thrown
|
|
484 if (op.result() == NULL) {
|
|
485 size_policy()->set_gc_time_limit_exceeded(false);
|
|
486 }
|
|
487 return op.result();
|
|
488 }
|
|
489 }
|
|
490
|
|
491 // The policy object will prevent us from looping forever. If the
|
|
492 // time spent in gc crosses a threshold, we will bail out.
|
|
493 loop_count++;
|
|
494 if ((result == NULL) && (QueuedAllocationWarningCount > 0) &&
|
|
495 (loop_count % QueuedAllocationWarningCount == 0)) {
|
|
496 warning("ParallelScavengeHeap::mem_allocate retries %d times \n\t"
|
|
497 " size=%d %s", loop_count, size, is_tlab ? "(TLAB)" : "");
|
|
498 }
|
|
499 }
|
|
500
|
|
501 return result;
|
|
502 }
|
|
503
|
|
504 // Failed allocation policy. Must be called from the VM thread, and
|
|
505 // only at a safepoint! Note that this method has policy for allocation
|
|
506 // flow, and NOT collection policy. So we do not check for gc collection
|
|
507 // time over limit here, that is the responsibility of the heap specific
|
|
508 // collection methods. This method decides where to attempt allocations,
|
|
509 // and when to attempt collections, but no collection specific policy.
|
|
510 HeapWord* ParallelScavengeHeap::failed_mem_allocate(size_t size, bool is_tlab) {
|
|
511 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
|
|
512 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
|
|
513 assert(!Universe::heap()->is_gc_active(), "not reentrant");
|
|
514 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
|
|
515
|
|
516 size_t mark_sweep_invocation_count = total_invocations();
|
|
517
|
|
518 // We assume (and assert!) that an allocation at this point will fail
|
|
519 // unless we collect.
|
|
520
|
|
521 // First level allocation failure, scavenge and allocate in young gen.
|
|
522 GCCauseSetter gccs(this, GCCause::_allocation_failure);
|
|
523 PSScavenge::invoke();
|
|
524 HeapWord* result = young_gen()->allocate(size, is_tlab);
|
|
525
|
|
526 // Second level allocation failure.
|
|
527 // Mark sweep and allocate in young generation.
|
|
528 if (result == NULL) {
|
|
529 // There is some chance the scavenge method decided to invoke mark_sweep.
|
|
530 // Don't mark sweep twice if so.
|
|
531 if (mark_sweep_invocation_count == total_invocations()) {
|
|
532 invoke_full_gc(false);
|
|
533 result = young_gen()->allocate(size, is_tlab);
|
|
534 }
|
|
535 }
|
|
536
|
|
537 // Third level allocation failure.
|
|
538 // After mark sweep and young generation allocation failure,
|
|
539 // allocate in old generation.
|
|
540 if (result == NULL && !is_tlab) {
|
|
541 result = old_gen()->allocate(size, is_tlab);
|
|
542 }
|
|
543
|
|
544 // Fourth level allocation failure. We're running out of memory.
|
|
545 // More complete mark sweep and allocate in young generation.
|
|
546 if (result == NULL) {
|
|
547 invoke_full_gc(true);
|
|
548 result = young_gen()->allocate(size, is_tlab);
|
|
549 }
|
|
550
|
|
551 // Fifth level allocation failure.
|
|
552 // After more complete mark sweep, allocate in old generation.
|
|
553 if (result == NULL && !is_tlab) {
|
|
554 result = old_gen()->allocate(size, is_tlab);
|
|
555 }
|
|
556
|
|
557 return result;
|
|
558 }
|
|
559
|
|
560 //
|
|
561 // This is the policy loop for allocating in the permanent generation.
|
|
562 // If the initial allocation fails, we create a vm operation which will
|
|
563 // cause a collection.
|
|
564 HeapWord* ParallelScavengeHeap::permanent_mem_allocate(size_t size) {
|
|
565 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
|
|
566 assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
|
|
567 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
|
|
568
|
|
569 HeapWord* result;
|
|
570
|
|
571 uint loop_count = 0;
|
|
572 uint gc_count = 0;
|
|
573 uint full_gc_count = 0;
|
|
574
|
|
575 do {
|
|
576 // We don't want to have multiple collections for a single filled generation.
|
|
577 // To prevent this, each thread tracks the total_collections() value, and if
|
|
578 // the count has changed, does not do a new collection.
|
|
579 //
|
|
580 // The collection count must be read only while holding the heap lock. VM
|
|
581 // operations also hold the heap lock during collections. There is a lock
|
|
582 // contention case where thread A blocks waiting on the Heap_lock, while
|
|
583 // thread B is holding it doing a collection. When thread A gets the lock,
|
|
584 // the collection count has already changed. To prevent duplicate collections,
|
|
585 // The policy MUST attempt allocations during the same period it reads the
|
|
586 // total_collections() value!
|
|
587 {
|
|
588 MutexLocker ml(Heap_lock);
|
|
589 gc_count = Universe::heap()->total_collections();
|
|
590 full_gc_count = Universe::heap()->total_full_collections();
|
|
591
|
|
592 result = perm_gen()->allocate_permanent(size);
|
|
593 }
|
|
594
|
|
595 if (result == NULL) {
|
|
596
|
|
597 // Exit the loop if the gc time limit has been exceeded.
|
|
598 // The allocation must have failed above (result must be NULL),
|
|
599 // and the most recent collection must have exceeded the
|
|
600 // gc time limit. Exit the loop so that an out-of-memory
|
|
601 // will be thrown (returning a NULL will do that), but
|
|
602 // clear gc_time_limit_exceeded so that the next collection
|
|
603 // will succeeded if the applications decides to handle the
|
|
604 // out-of-memory and tries to go on.
|
|
605 if (size_policy()->gc_time_limit_exceeded()) {
|
|
606 size_policy()->set_gc_time_limit_exceeded(false);
|
|
607 if (PrintGCDetails && Verbose) {
|
|
608 gclog_or_tty->print_cr("ParallelScavengeHeap::permanent_mem_allocate: "
|
|
609 "return NULL because gc_time_limit_exceeded is set");
|
|
610 }
|
|
611 assert(result == NULL, "Allocation did not fail");
|
|
612 return NULL;
|
|
613 }
|
|
614
|
|
615 // Generate a VM operation
|
|
616 VM_ParallelGCFailedPermanentAllocation op(size, gc_count, full_gc_count);
|
|
617 VMThread::execute(&op);
|
|
618
|
|
619 // Did the VM operation execute? If so, return the result directly.
|
|
620 // This prevents us from looping until time out on requests that can
|
|
621 // not be satisfied.
|
|
622 if (op.prologue_succeeded()) {
|
|
623 assert(Universe::heap()->is_in_permanent_or_null(op.result()),
|
|
624 "result not in heap");
|
|
625 // If a NULL results is being returned, an out-of-memory
|
|
626 // will be thrown now. Clear the gc_time_limit_exceeded
|
|
627 // flag to avoid the following situation.
|
|
628 // gc_time_limit_exceeded is set during a collection
|
|
629 // the collection fails to return enough space and an OOM is thrown
|
|
630 // the next GC is skipped because the gc_time_limit_exceeded
|
|
631 // flag is set and another OOM is thrown
|
|
632 if (op.result() == NULL) {
|
|
633 size_policy()->set_gc_time_limit_exceeded(false);
|
|
634 }
|
|
635 return op.result();
|
|
636 }
|
|
637 }
|
|
638
|
|
639 // The policy object will prevent us from looping forever. If the
|
|
640 // time spent in gc crosses a threshold, we will bail out.
|
|
641 loop_count++;
|
|
642 if ((QueuedAllocationWarningCount > 0) &&
|
|
643 (loop_count % QueuedAllocationWarningCount == 0)) {
|
|
644 warning("ParallelScavengeHeap::permanent_mem_allocate retries %d times \n\t"
|
|
645 " size=%d", loop_count, size);
|
|
646 }
|
|
647 } while (result == NULL);
|
|
648
|
|
649 return result;
|
|
650 }
|
|
651
|
|
652 //
|
|
653 // This is the policy code for permanent allocations which have failed
|
|
654 // and require a collection. Note that just as in failed_mem_allocate,
|
|
655 // we do not set collection policy, only where & when to allocate and
|
|
656 // collect.
|
|
657 HeapWord* ParallelScavengeHeap::failed_permanent_mem_allocate(size_t size) {
|
|
658 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
|
|
659 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
|
|
660 assert(!Universe::heap()->is_gc_active(), "not reentrant");
|
|
661 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
|
|
662 assert(size > perm_gen()->free_in_words(), "Allocation should fail");
|
|
663
|
|
664 // We assume (and assert!) that an allocation at this point will fail
|
|
665 // unless we collect.
|
|
666
|
|
667 // First level allocation failure. Mark-sweep and allocate in perm gen.
|
|
668 GCCauseSetter gccs(this, GCCause::_allocation_failure);
|
|
669 invoke_full_gc(false);
|
|
670 HeapWord* result = perm_gen()->allocate_permanent(size);
|
|
671
|
|
672 // Second level allocation failure. We're running out of memory.
|
|
673 if (result == NULL) {
|
|
674 invoke_full_gc(true);
|
|
675 result = perm_gen()->allocate_permanent(size);
|
|
676 }
|
|
677
|
|
678 return result;
|
|
679 }
|
|
680
|
|
681 void ParallelScavengeHeap::ensure_parsability(bool retire_tlabs) {
|
|
682 CollectedHeap::ensure_parsability(retire_tlabs);
|
|
683 young_gen()->eden_space()->ensure_parsability();
|
|
684 }
|
|
685
|
|
686 size_t ParallelScavengeHeap::unsafe_max_alloc() {
|
|
687 return young_gen()->eden_space()->free_in_bytes();
|
|
688 }
|
|
689
|
|
690 size_t ParallelScavengeHeap::tlab_capacity(Thread* thr) const {
|
|
691 return young_gen()->eden_space()->tlab_capacity(thr);
|
|
692 }
|
|
693
|
|
694 size_t ParallelScavengeHeap::unsafe_max_tlab_alloc(Thread* thr) const {
|
|
695 return young_gen()->eden_space()->unsafe_max_tlab_alloc(thr);
|
|
696 }
|
|
697
|
|
698 HeapWord* ParallelScavengeHeap::allocate_new_tlab(size_t size) {
|
|
699 return young_gen()->allocate(size, true);
|
|
700 }
|
|
701
|
|
702 void ParallelScavengeHeap::fill_all_tlabs(bool retire) {
|
|
703 CollectedHeap::fill_all_tlabs(retire);
|
|
704 }
|
|
705
|
|
706 void ParallelScavengeHeap::accumulate_statistics_all_tlabs() {
|
|
707 CollectedHeap::accumulate_statistics_all_tlabs();
|
|
708 }
|
|
709
|
|
710 void ParallelScavengeHeap::resize_all_tlabs() {
|
|
711 CollectedHeap::resize_all_tlabs();
|
|
712 }
|
|
713
|
|
714 // This method is used by System.gc() and JVMTI.
|
|
715 void ParallelScavengeHeap::collect(GCCause::Cause cause) {
|
|
716 assert(!Heap_lock->owned_by_self(),
|
|
717 "this thread should not own the Heap_lock");
|
|
718
|
|
719 unsigned int gc_count = 0;
|
|
720 unsigned int full_gc_count = 0;
|
|
721 {
|
|
722 MutexLocker ml(Heap_lock);
|
|
723 // This value is guarded by the Heap_lock
|
|
724 gc_count = Universe::heap()->total_collections();
|
|
725 full_gc_count = Universe::heap()->total_full_collections();
|
|
726 }
|
|
727
|
|
728 VM_ParallelGCSystemGC op(gc_count, full_gc_count, cause);
|
|
729 VMThread::execute(&op);
|
|
730 }
|
|
731
|
|
732 // This interface assumes that it's being called by the
|
|
733 // vm thread. It collects the heap assuming that the
|
|
734 // heap lock is already held and that we are executing in
|
|
735 // the context of the vm thread.
|
|
736 void ParallelScavengeHeap::collect_as_vm_thread(GCCause::Cause cause) {
|
|
737 assert(Thread::current()->is_VM_thread(), "Precondition#1");
|
|
738 assert(Heap_lock->is_locked(), "Precondition#2");
|
|
739 GCCauseSetter gcs(this, cause);
|
|
740 switch (cause) {
|
|
741 case GCCause::_heap_inspection:
|
|
742 case GCCause::_heap_dump: {
|
|
743 HandleMark hm;
|
|
744 invoke_full_gc(false);
|
|
745 break;
|
|
746 }
|
|
747 default: // XXX FIX ME
|
|
748 ShouldNotReachHere();
|
|
749 }
|
|
750 }
|
|
751
|
|
752
|
|
753 void ParallelScavengeHeap::oop_iterate(OopClosure* cl) {
|
|
754 Unimplemented();
|
|
755 }
|
|
756
|
|
757 void ParallelScavengeHeap::object_iterate(ObjectClosure* cl) {
|
|
758 young_gen()->object_iterate(cl);
|
|
759 old_gen()->object_iterate(cl);
|
|
760 perm_gen()->object_iterate(cl);
|
|
761 }
|
|
762
|
|
763 void ParallelScavengeHeap::permanent_oop_iterate(OopClosure* cl) {
|
|
764 Unimplemented();
|
|
765 }
|
|
766
|
|
767 void ParallelScavengeHeap::permanent_object_iterate(ObjectClosure* cl) {
|
|
768 perm_gen()->object_iterate(cl);
|
|
769 }
|
|
770
|
|
771 HeapWord* ParallelScavengeHeap::block_start(const void* addr) const {
|
|
772 if (young_gen()->is_in_reserved(addr)) {
|
|
773 assert(young_gen()->is_in(addr),
|
|
774 "addr should be in allocated part of young gen");
|
|
775 Unimplemented();
|
|
776 } else if (old_gen()->is_in_reserved(addr)) {
|
|
777 assert(old_gen()->is_in(addr),
|
|
778 "addr should be in allocated part of old gen");
|
|
779 return old_gen()->start_array()->object_start((HeapWord*)addr);
|
|
780 } else if (perm_gen()->is_in_reserved(addr)) {
|
|
781 assert(perm_gen()->is_in(addr),
|
|
782 "addr should be in allocated part of perm gen");
|
|
783 return perm_gen()->start_array()->object_start((HeapWord*)addr);
|
|
784 }
|
|
785 return 0;
|
|
786 }
|
|
787
|
|
788 size_t ParallelScavengeHeap::block_size(const HeapWord* addr) const {
|
|
789 return oop(addr)->size();
|
|
790 }
|
|
791
|
|
792 bool ParallelScavengeHeap::block_is_obj(const HeapWord* addr) const {
|
|
793 return block_start(addr) == addr;
|
|
794 }
|
|
795
|
|
796 jlong ParallelScavengeHeap::millis_since_last_gc() {
|
|
797 return UseParallelOldGC ?
|
|
798 PSParallelCompact::millis_since_last_gc() :
|
|
799 PSMarkSweep::millis_since_last_gc();
|
|
800 }
|
|
801
|
|
802 void ParallelScavengeHeap::prepare_for_verify() {
|
|
803 ensure_parsability(false); // no need to retire TLABs for verification
|
|
804 }
|
|
805
|
|
806 void ParallelScavengeHeap::print() const { print_on(tty); }
|
|
807
|
|
808 void ParallelScavengeHeap::print_on(outputStream* st) const {
|
|
809 young_gen()->print_on(st);
|
|
810 old_gen()->print_on(st);
|
|
811 perm_gen()->print_on(st);
|
|
812 }
|
|
813
|
|
814 void ParallelScavengeHeap::gc_threads_do(ThreadClosure* tc) const {
|
|
815 PSScavenge::gc_task_manager()->threads_do(tc);
|
|
816 }
|
|
817
|
|
818 void ParallelScavengeHeap::print_gc_threads_on(outputStream* st) const {
|
|
819 PSScavenge::gc_task_manager()->print_threads_on(st);
|
|
820 }
|
|
821
|
|
822 void ParallelScavengeHeap::print_tracing_info() const {
|
|
823 if (TraceGen0Time) {
|
|
824 double time = PSScavenge::accumulated_time()->seconds();
|
|
825 tty->print_cr("[Accumulated GC generation 0 time %3.7f secs]", time);
|
|
826 }
|
|
827 if (TraceGen1Time) {
|
|
828 double time = PSMarkSweep::accumulated_time()->seconds();
|
|
829 tty->print_cr("[Accumulated GC generation 1 time %3.7f secs]", time);
|
|
830 }
|
|
831 }
|
|
832
|
|
833
|
|
834 void ParallelScavengeHeap::verify(bool allow_dirty, bool silent) {
|
|
835 // Why do we need the total_collections()-filter below?
|
|
836 if (total_collections() > 0) {
|
|
837 if (!silent) {
|
|
838 gclog_or_tty->print("permanent ");
|
|
839 }
|
|
840 perm_gen()->verify(allow_dirty);
|
|
841
|
|
842 if (!silent) {
|
|
843 gclog_or_tty->print("tenured ");
|
|
844 }
|
|
845 old_gen()->verify(allow_dirty);
|
|
846
|
|
847 if (!silent) {
|
|
848 gclog_or_tty->print("eden ");
|
|
849 }
|
|
850 young_gen()->verify(allow_dirty);
|
|
851 }
|
|
852 if (!silent) {
|
|
853 gclog_or_tty->print("ref_proc ");
|
|
854 }
|
|
855 ReferenceProcessor::verify();
|
|
856 }
|
|
857
|
|
858 void ParallelScavengeHeap::print_heap_change(size_t prev_used) {
|
|
859 if (PrintGCDetails && Verbose) {
|
|
860 gclog_or_tty->print(" " SIZE_FORMAT
|
|
861 "->" SIZE_FORMAT
|
|
862 "(" SIZE_FORMAT ")",
|
|
863 prev_used, used(), capacity());
|
|
864 } else {
|
|
865 gclog_or_tty->print(" " SIZE_FORMAT "K"
|
|
866 "->" SIZE_FORMAT "K"
|
|
867 "(" SIZE_FORMAT "K)",
|
|
868 prev_used / K, used() / K, capacity() / K);
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869 }
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870 }
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871
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872 ParallelScavengeHeap* ParallelScavengeHeap::heap() {
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873 assert(_psh != NULL, "Uninitialized access to ParallelScavengeHeap::heap()");
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874 assert(_psh->kind() == CollectedHeap::ParallelScavengeHeap, "not a parallel scavenge heap");
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875 return _psh;
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876 }
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877
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878 // Before delegating the resize to the young generation,
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879 // the reserved space for the young and old generations
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880 // may be changed to accomodate the desired resize.
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881 void ParallelScavengeHeap::resize_young_gen(size_t eden_size,
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882 size_t survivor_size) {
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883 if (UseAdaptiveGCBoundary) {
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884 if (size_policy()->bytes_absorbed_from_eden() != 0) {
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885 size_policy()->reset_bytes_absorbed_from_eden();
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886 return; // The generation changed size already.
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887 }
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888 gens()->adjust_boundary_for_young_gen_needs(eden_size, survivor_size);
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889 }
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890
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891 // Delegate the resize to the generation.
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892 _young_gen->resize(eden_size, survivor_size);
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|
893 }
|
|
894
|
|
895 // Before delegating the resize to the old generation,
|
|
896 // the reserved space for the young and old generations
|
|
897 // may be changed to accomodate the desired resize.
|
|
898 void ParallelScavengeHeap::resize_old_gen(size_t desired_free_space) {
|
|
899 if (UseAdaptiveGCBoundary) {
|
|
900 if (size_policy()->bytes_absorbed_from_eden() != 0) {
|
|
901 size_policy()->reset_bytes_absorbed_from_eden();
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|
902 return; // The generation changed size already.
|
|
903 }
|
|
904 gens()->adjust_boundary_for_old_gen_needs(desired_free_space);
|
|
905 }
|
|
906
|
|
907 // Delegate the resize to the generation.
|
|
908 _old_gen->resize(desired_free_space);
|
|
909 }
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