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1 /* |
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2 * Copyright (c) 2011, 2014, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
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22 * |
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23 */ |
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24 |
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25 #include "precompiled.hpp" |
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26 #include "gc_implementation/g1/heapRegionRemSet.hpp" |
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27 #include "gc_implementation/g1/heapRegionSet.inline.hpp" |
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28 |
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29 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC |
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30 |
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31 uint FreeRegionList::_unrealistically_long_length = 0; |
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32 |
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33 void HeapRegionSetBase::fill_in_ext_msg(hrs_ext_msg* msg, const char* message) { |
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34 msg->append("[%s] %s ln: %u cy: "SIZE_FORMAT, |
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35 name(), message, length(), total_capacity_bytes()); |
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36 fill_in_ext_msg_extra(msg); |
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37 } |
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38 |
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39 #ifndef PRODUCT |
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40 void HeapRegionSetBase::verify_region(HeapRegion* hr) { |
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41 assert(hr->containing_set() == this, err_msg("Inconsistent containing set for %u", hr->hrs_index())); |
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42 assert(!hr->is_young(), err_msg("Adding young region %u", hr->hrs_index())); // currently we don't use these sets for young regions |
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43 assert(hr->isHumongous() == regions_humongous(), err_msg("Wrong humongous state for region %u and set %s", hr->hrs_index(), name())); |
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44 assert(hr->is_empty() == regions_empty(), err_msg("Wrong empty state for region %u and set %s", hr->hrs_index(), name())); |
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45 assert(hr->rem_set()->verify_ready_for_par_iteration(), err_msg("Wrong iteration state %u", hr->hrs_index())); |
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46 } |
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47 #endif |
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48 |
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49 void HeapRegionSetBase::verify() { |
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50 // It's important that we also observe the MT safety protocol even |
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51 // for the verification calls. If we do verification without the |
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52 // appropriate locks and the set changes underneath our feet |
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53 // verification might fail and send us on a wild goose chase. |
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54 check_mt_safety(); |
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55 |
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56 guarantee(( is_empty() && length() == 0 && total_capacity_bytes() == 0) || |
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57 (!is_empty() && length() >= 0 && total_capacity_bytes() >= 0), |
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58 hrs_ext_msg(this, "invariant")); |
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59 } |
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60 |
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61 void HeapRegionSetBase::verify_start() { |
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62 // See comment in verify() about MT safety and verification. |
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63 check_mt_safety(); |
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64 assert(!_verify_in_progress, |
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65 hrs_ext_msg(this, "verification should not be in progress")); |
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66 |
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67 // Do the basic verification first before we do the checks over the regions. |
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68 HeapRegionSetBase::verify(); |
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69 |
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70 _verify_in_progress = true; |
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71 } |
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72 |
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73 void HeapRegionSetBase::verify_end() { |
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74 // See comment in verify() about MT safety and verification. |
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75 check_mt_safety(); |
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76 assert(_verify_in_progress, |
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77 hrs_ext_msg(this, "verification should be in progress")); |
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78 |
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79 _verify_in_progress = false; |
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80 } |
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81 |
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82 void HeapRegionSetBase::print_on(outputStream* out, bool print_contents) { |
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83 out->cr(); |
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84 out->print_cr("Set: %s ("PTR_FORMAT")", name(), this); |
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85 out->print_cr(" Region Assumptions"); |
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86 out->print_cr(" humongous : %s", BOOL_TO_STR(regions_humongous())); |
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87 out->print_cr(" empty : %s", BOOL_TO_STR(regions_empty())); |
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88 out->print_cr(" Attributes"); |
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89 out->print_cr(" length : %14u", length()); |
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90 out->print_cr(" total capacity : "SIZE_FORMAT_W(14)" bytes", |
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91 total_capacity_bytes()); |
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92 } |
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93 |
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94 HeapRegionSetBase::HeapRegionSetBase(const char* name, bool humongous, bool empty, HRSMtSafeChecker* mt_safety_checker) |
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95 : _name(name), _verify_in_progress(false), |
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96 _is_humongous(humongous), _is_empty(empty), _mt_safety_checker(mt_safety_checker), |
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97 _count() |
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98 { } |
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99 |
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100 void FreeRegionList::set_unrealistically_long_length(uint len) { |
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101 guarantee(_unrealistically_long_length == 0, "should only be set once"); |
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102 _unrealistically_long_length = len; |
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103 } |
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104 |
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105 void FreeRegionList::fill_in_ext_msg_extra(hrs_ext_msg* msg) { |
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106 msg->append(" hd: "PTR_FORMAT" tl: "PTR_FORMAT, head(), tail()); |
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107 } |
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108 |
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109 void FreeRegionList::add_as_head_or_tail(FreeRegionList* from_list, bool as_head) { |
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110 check_mt_safety(); |
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111 from_list->check_mt_safety(); |
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112 |
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113 verify_optional(); |
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114 from_list->verify_optional(); |
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115 |
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116 if (from_list->is_empty()) { |
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117 return; |
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118 } |
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119 |
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120 #ifdef ASSERT |
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121 FreeRegionListIterator iter(from_list); |
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122 while (iter.more_available()) { |
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123 HeapRegion* hr = iter.get_next(); |
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124 // In set_containing_set() we check that we either set the value |
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125 // from NULL to non-NULL or vice versa to catch bugs. So, we have |
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126 // to NULL it first before setting it to the value. |
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127 hr->set_containing_set(NULL); |
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128 hr->set_containing_set(this); |
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129 } |
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130 #endif // ASSERT |
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131 |
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132 if (_head == NULL) { |
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133 assert(length() == 0 && _tail == NULL, hrs_ext_msg(this, "invariant")); |
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134 _head = from_list->_head; |
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135 _tail = from_list->_tail; |
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136 } else { |
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137 assert(length() > 0 && _tail != NULL, hrs_ext_msg(this, "invariant")); |
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138 if (as_head) { |
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139 from_list->_tail->set_next(_head); |
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140 _head->set_prev(from_list->_tail); |
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141 _head = from_list->_head; |
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142 } else { |
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143 _tail->set_next(from_list->_head); |
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144 from_list->_head->set_prev(_tail); |
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145 _tail = from_list->_tail; |
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146 } |
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147 } |
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148 |
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149 _count.increment(from_list->length(), from_list->total_capacity_bytes()); |
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150 from_list->clear(); |
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151 |
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152 verify_optional(); |
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153 from_list->verify_optional(); |
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154 } |
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155 |
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156 void FreeRegionList::add_as_head(FreeRegionList* from_list) { |
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157 add_as_head_or_tail(from_list, true /* as_head */); |
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158 } |
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159 |
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160 void FreeRegionList::add_as_tail(FreeRegionList* from_list) { |
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161 add_as_head_or_tail(from_list, false /* as_head */); |
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162 } |
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163 |
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164 void FreeRegionList::remove_all() { |
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165 check_mt_safety(); |
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166 verify_optional(); |
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167 |
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168 HeapRegion* curr = _head; |
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169 while (curr != NULL) { |
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170 verify_region(curr); |
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171 |
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172 HeapRegion* next = curr->next(); |
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173 curr->set_next(NULL); |
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174 curr->set_prev(NULL); |
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175 curr->set_containing_set(NULL); |
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176 curr = next; |
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177 } |
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178 clear(); |
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179 |
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180 verify_optional(); |
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181 } |
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182 |
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183 void FreeRegionList::add_ordered(FreeRegionList* from_list) { |
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184 check_mt_safety(); |
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185 from_list->check_mt_safety(); |
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186 |
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187 verify_optional(); |
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188 from_list->verify_optional(); |
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189 |
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190 if (from_list->is_empty()) { |
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191 return; |
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192 } |
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193 |
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194 if (is_empty()) { |
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195 add_as_head(from_list); |
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196 return; |
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197 } |
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198 |
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199 #ifdef ASSERT |
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200 FreeRegionListIterator iter(from_list); |
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201 while (iter.more_available()) { |
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202 HeapRegion* hr = iter.get_next(); |
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203 // In set_containing_set() we check that we either set the value |
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204 // from NULL to non-NULL or vice versa to catch bugs. So, we have |
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205 // to NULL it first before setting it to the value. |
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206 hr->set_containing_set(NULL); |
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207 hr->set_containing_set(this); |
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208 } |
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209 #endif // ASSERT |
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210 |
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211 HeapRegion* curr_to = _head; |
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212 HeapRegion* curr_from = from_list->_head; |
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213 |
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214 while (curr_from != NULL) { |
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215 while (curr_to != NULL && curr_to->hrs_index() < curr_from->hrs_index()) { |
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216 curr_to = curr_to->next(); |
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217 } |
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218 |
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219 if (curr_to == NULL) { |
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220 // The rest of the from list should be added as tail |
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221 _tail->set_next(curr_from); |
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222 curr_from->set_prev(_tail); |
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223 curr_from = NULL; |
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224 } else { |
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225 HeapRegion* next_from = curr_from->next(); |
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226 |
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227 curr_from->set_next(curr_to); |
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228 curr_from->set_prev(curr_to->prev()); |
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229 if (curr_to->prev() == NULL) { |
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230 _head = curr_from; |
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231 } else { |
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232 curr_to->prev()->set_next(curr_from); |
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233 } |
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234 curr_to->set_prev(curr_from); |
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235 |
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236 curr_from = next_from; |
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237 } |
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238 } |
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239 |
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240 if (_tail->hrs_index() < from_list->_tail->hrs_index()) { |
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241 _tail = from_list->_tail; |
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242 } |
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243 |
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244 _count.increment(from_list->length(), from_list->total_capacity_bytes()); |
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245 from_list->clear(); |
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246 |
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247 verify_optional(); |
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248 from_list->verify_optional(); |
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249 } |
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250 |
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251 void FreeRegionList::remove_all_pending(uint target_count) { |
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252 check_mt_safety(); |
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253 assert(target_count > 1, hrs_ext_msg(this, "pre-condition")); |
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254 assert(!is_empty(), hrs_ext_msg(this, "pre-condition")); |
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255 |
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256 verify_optional(); |
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257 DEBUG_ONLY(uint old_length = length();) |
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258 |
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259 HeapRegion* curr = _head; |
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260 uint count = 0; |
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261 while (curr != NULL) { |
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262 verify_region(curr); |
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263 HeapRegion* next = curr->next(); |
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264 HeapRegion* prev = curr->prev(); |
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265 |
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266 if (curr->pending_removal()) { |
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267 assert(count < target_count, |
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268 hrs_err_msg("[%s] should not come across more regions " |
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269 "pending for removal than target_count: %u", |
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270 name(), target_count)); |
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271 |
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272 if (prev == NULL) { |
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273 assert(_head == curr, hrs_ext_msg(this, "invariant")); |
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274 _head = next; |
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275 } else { |
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276 assert(_head != curr, hrs_ext_msg(this, "invariant")); |
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277 prev->set_next(next); |
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278 } |
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279 if (next == NULL) { |
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280 assert(_tail == curr, hrs_ext_msg(this, "invariant")); |
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281 _tail = prev; |
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282 } else { |
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283 assert(_tail != curr, hrs_ext_msg(this, "invariant")); |
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284 next->set_prev(prev); |
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285 } |
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286 if (_last = curr) { |
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287 _last = NULL; |
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288 } |
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289 |
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290 curr->set_next(NULL); |
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291 curr->set_prev(NULL); |
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292 remove(curr); |
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293 curr->set_pending_removal(false); |
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294 |
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295 count += 1; |
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296 |
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297 // If we have come across the target number of regions we can |
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298 // just bail out. However, for debugging purposes, we can just |
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299 // carry on iterating to make sure there are not more regions |
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300 // tagged with pending removal. |
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301 DEBUG_ONLY(if (count == target_count) break;) |
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302 } |
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303 curr = next; |
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304 } |
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305 |
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306 assert(count == target_count, |
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307 hrs_err_msg("[%s] count: %u should be == target_count: %u", |
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308 name(), count, target_count)); |
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309 assert(length() + target_count == old_length, |
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310 hrs_err_msg("[%s] new length should be consistent " |
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311 "new length: %u old length: %u target_count: %u", |
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312 name(), length(), old_length, target_count)); |
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313 |
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314 verify_optional(); |
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315 } |
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316 |
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317 void FreeRegionList::verify() { |
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318 // See comment in HeapRegionSetBase::verify() about MT safety and |
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319 // verification. |
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320 check_mt_safety(); |
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321 |
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322 // This will also do the basic verification too. |
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323 verify_start(); |
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324 |
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325 verify_list(); |
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326 |
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327 verify_end(); |
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328 } |
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329 |
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330 void FreeRegionList::clear() { |
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331 _count = HeapRegionSetCount(); |
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332 _head = NULL; |
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333 _tail = NULL; |
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334 _last = NULL; |
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335 } |
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336 |
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337 void FreeRegionList::print_on(outputStream* out, bool print_contents) { |
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338 HeapRegionSetBase::print_on(out, print_contents); |
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339 out->print_cr(" Linking"); |
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340 out->print_cr(" head : "PTR_FORMAT, _head); |
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341 out->print_cr(" tail : "PTR_FORMAT, _tail); |
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342 |
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343 if (print_contents) { |
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344 out->print_cr(" Contents"); |
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345 FreeRegionListIterator iter(this); |
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346 while (iter.more_available()) { |
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347 HeapRegion* hr = iter.get_next(); |
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348 hr->print_on(out); |
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349 } |
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350 } |
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351 } |
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352 |
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353 void FreeRegionList::verify_list() { |
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354 HeapRegion* curr = head(); |
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355 HeapRegion* prev1 = NULL; |
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356 HeapRegion* prev0 = NULL; |
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357 uint count = 0; |
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358 size_t capacity = 0; |
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359 uint last_index = 0; |
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360 |
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361 guarantee(_head == NULL || _head->prev() == NULL, "_head should not have a prev"); |
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362 while (curr != NULL) { |
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363 verify_region(curr); |
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364 |
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365 count++; |
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366 guarantee(count < _unrealistically_long_length, |
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367 hrs_err_msg("[%s] the calculated length: %u seems very long, is there maybe a cycle? curr: "PTR_FORMAT" prev0: "PTR_FORMAT" " "prev1: "PTR_FORMAT" length: %u", name(), count, curr, prev0, prev1, length())); |
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368 |
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369 if (curr->next() != NULL) { |
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370 guarantee(curr->next()->prev() == curr, "Next or prev pointers messed up"); |
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371 } |
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372 guarantee(curr->hrs_index() == 0 || curr->hrs_index() > last_index, "List should be sorted"); |
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373 last_index = curr->hrs_index(); |
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374 |
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375 capacity += curr->capacity(); |
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376 |
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377 prev1 = prev0; |
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378 prev0 = curr; |
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379 curr = curr->next(); |
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380 } |
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381 |
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382 guarantee(tail() == prev0, err_msg("Expected %s to end with %u but it ended with %u.", name(), tail()->hrs_index(), prev0->hrs_index())); |
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383 guarantee(_tail == NULL || _tail->next() == NULL, "_tail should not have a next"); |
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384 guarantee(length() == count, err_msg("%s count mismatch. Expected %u, actual %u.", name(), length(), count)); |
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385 guarantee(total_capacity_bytes() == capacity, err_msg("%s capacity mismatch. Expected " SIZE_FORMAT ", actual " SIZE_FORMAT, |
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386 name(), total_capacity_bytes(), capacity)); |
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387 } |
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388 |
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389 // Note on the check_mt_safety() methods below: |
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390 // |
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391 // Verification of the "master" heap region sets / lists that are |
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392 // maintained by G1CollectedHeap is always done during a STW pause and |
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393 // by the VM thread at the start / end of the pause. The standard |
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394 // verification methods all assert check_mt_safety(). This is |
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395 // important as it ensures that verification is done without |
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396 // concurrent updates taking place at the same time. It follows, that, |
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397 // for the "master" heap region sets / lists, the check_mt_safety() |
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398 // method should include the VM thread / STW case. |
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399 |
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400 void MasterFreeRegionListMtSafeChecker::check() { |
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401 // Master Free List MT safety protocol: |
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402 // (a) If we're at a safepoint, operations on the master free list |
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403 // should be invoked by either the VM thread (which will serialize |
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404 // them) or by the GC workers while holding the |
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405 // FreeList_lock. |
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406 // (b) If we're not at a safepoint, operations on the master free |
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407 // list should be invoked while holding the Heap_lock. |
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408 |
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409 if (SafepointSynchronize::is_at_safepoint()) { |
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410 guarantee(Thread::current()->is_VM_thread() || |
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411 FreeList_lock->owned_by_self(), "master free list MT safety protocol at a safepoint"); |
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412 } else { |
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413 guarantee(Heap_lock->owned_by_self(), "master free list MT safety protocol outside a safepoint"); |
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414 } |
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415 } |
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416 |
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417 void SecondaryFreeRegionListMtSafeChecker::check() { |
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418 // Secondary Free List MT safety protocol: |
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419 // Operations on the secondary free list should always be invoked |
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420 // while holding the SecondaryFreeList_lock. |
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421 |
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422 guarantee(SecondaryFreeList_lock->owned_by_self(), "secondary free list MT safety protocol"); |
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423 } |
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424 |
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425 void OldRegionSetMtSafeChecker::check() { |
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426 // Master Old Set MT safety protocol: |
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427 // (a) If we're at a safepoint, operations on the master old set |
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428 // should be invoked: |
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429 // - by the VM thread (which will serialize them), or |
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430 // - by the GC workers while holding the FreeList_lock, if we're |
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431 // at a safepoint for an evacuation pause (this lock is taken |
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432 // anyway when an GC alloc region is retired so that a new one |
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433 // is allocated from the free list), or |
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434 // - by the GC workers while holding the OldSets_lock, if we're at a |
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435 // safepoint for a cleanup pause. |
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436 // (b) If we're not at a safepoint, operations on the master old set |
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437 // should be invoked while holding the Heap_lock. |
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438 |
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439 if (SafepointSynchronize::is_at_safepoint()) { |
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440 guarantee(Thread::current()->is_VM_thread() |
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441 || FreeList_lock->owned_by_self() || OldSets_lock->owned_by_self(), |
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442 "master old set MT safety protocol at a safepoint"); |
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443 } else { |
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444 guarantee(Heap_lock->owned_by_self(), "master old set MT safety protocol outside a safepoint"); |
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445 } |
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446 } |
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447 |
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448 void HumongousRegionSetMtSafeChecker::check() { |
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449 // Humongous Set MT safety protocol: |
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450 // (a) If we're at a safepoint, operations on the master humongous |
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451 // set should be invoked by either the VM thread (which will |
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452 // serialize them) or by the GC workers while holding the |
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453 // OldSets_lock. |
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454 // (b) If we're not at a safepoint, operations on the master |
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455 // humongous set should be invoked while holding the Heap_lock. |
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456 |
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457 if (SafepointSynchronize::is_at_safepoint()) { |
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458 guarantee(Thread::current()->is_VM_thread() || |
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459 OldSets_lock->owned_by_self(), |
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460 "master humongous set MT safety protocol at a safepoint"); |
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461 } else { |
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462 guarantee(Heap_lock->owned_by_self(), |
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463 "master humongous set MT safety protocol outside a safepoint"); |
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464 } |
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465 } |