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annotate src/share/vm/memory/referenceProcessor.cpp @ 18136:52b8826ef035

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Backout wrong change in 2a69cbe850a8
author Gilles Duboscq <duboscq@ssw.jku.at>
date Tue, 21 Oct 2014 10:20:33 +0200
parents 52b4284cb496
children 7848fc12602b
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1 /*
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2 * Copyright (c) 2001, 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 "classfile/javaClasses.hpp"
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27 #include "classfile/systemDictionary.hpp"
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28 #include "gc_implementation/shared/gcTimer.hpp"
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29 #include "gc_implementation/shared/gcTraceTime.hpp"
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30 #include "gc_interface/collectedHeap.hpp"
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31 #include "gc_interface/collectedHeap.inline.hpp"
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32 #include "memory/referencePolicy.hpp"
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33 #include "memory/referenceProcessor.hpp"
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34 #include "oops/oop.inline.hpp"
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35 #include "runtime/java.hpp"
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36 #include "runtime/jniHandles.hpp"
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37
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38 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
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39
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40 ReferencePolicy* ReferenceProcessor::_always_clear_soft_ref_policy = NULL;
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41 ReferencePolicy* ReferenceProcessor::_default_soft_ref_policy = NULL;
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42 bool ReferenceProcessor::_pending_list_uses_discovered_field = false;
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43 jlong ReferenceProcessor::_soft_ref_timestamp_clock = 0;
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44
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45 void referenceProcessor_init() {
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46 ReferenceProcessor::init_statics();
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47 }
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48
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49 void ReferenceProcessor::init_statics() {
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50 // We need a monotonically non-deccreasing time in ms but
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51 // os::javaTimeMillis() does not guarantee monotonicity.
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52 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
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53
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54 // Initialize the soft ref timestamp clock.
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55 _soft_ref_timestamp_clock = now;
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56 // Also update the soft ref clock in j.l.r.SoftReference
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57 java_lang_ref_SoftReference::set_clock(_soft_ref_timestamp_clock);
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58
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59 _always_clear_soft_ref_policy = new AlwaysClearPolicy();
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60 _default_soft_ref_policy = new COMPILER2_PRESENT(LRUMaxHeapPolicy())
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61 NOT_COMPILER2(LRUCurrentHeapPolicy());
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62 if (_always_clear_soft_ref_policy == NULL || _default_soft_ref_policy == NULL) {
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63 vm_exit_during_initialization("Could not allocate reference policy object");
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64 }
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65 guarantee(RefDiscoveryPolicy == ReferenceBasedDiscovery ||
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66 RefDiscoveryPolicy == ReferentBasedDiscovery,
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67 "Unrecongnized RefDiscoveryPolicy");
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68 _pending_list_uses_discovered_field = JDK_Version::current().pending_list_uses_discovered_field();
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69 }
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70
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71 void ReferenceProcessor::enable_discovery(bool verify_disabled, bool check_no_refs) {
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72 #ifdef ASSERT
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73 // Verify that we're not currently discovering refs
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74 assert(!verify_disabled || !_discovering_refs, "nested call?");
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75
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76 if (check_no_refs) {
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77 // Verify that the discovered lists are empty
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78 verify_no_references_recorded();
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79 }
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80 #endif // ASSERT
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81
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82 // Someone could have modified the value of the static
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83 // field in the j.l.r.SoftReference class that holds the
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84 // soft reference timestamp clock using reflection or
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85 // Unsafe between GCs. Unconditionally update the static
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86 // field in ReferenceProcessor here so that we use the new
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87 // value during reference discovery.
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88
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89 _soft_ref_timestamp_clock = java_lang_ref_SoftReference::clock();
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90 _discovering_refs = true;
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91 }
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92
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93 ReferenceProcessor::ReferenceProcessor(MemRegion span,
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94 bool mt_processing,
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95 uint mt_processing_degree,
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96 bool mt_discovery,
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97 uint mt_discovery_degree,
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98 bool atomic_discovery,
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99 BoolObjectClosure* is_alive_non_header) :
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100 _discovering_refs(false),
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101 _enqueuing_is_done(false),
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102 _is_alive_non_header(is_alive_non_header),
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103 _processing_is_mt(mt_processing),
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104 _next_id(0)
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105 {
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106 _span = span;
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107 _discovery_is_atomic = atomic_discovery;
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108 _discovery_is_mt = mt_discovery;
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109 _num_q = MAX2(1U, mt_processing_degree);
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110 _max_num_q = MAX2(_num_q, mt_discovery_degree);
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111 _discovered_refs = NEW_C_HEAP_ARRAY(DiscoveredList,
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112 _max_num_q * number_of_subclasses_of_ref(), mtGC);
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113
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114 if (_discovered_refs == NULL) {
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115 vm_exit_during_initialization("Could not allocated RefProc Array");
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116 }
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117 _discoveredSoftRefs = &_discovered_refs[0];
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118 _discoveredWeakRefs = &_discoveredSoftRefs[_max_num_q];
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119 _discoveredFinalRefs = &_discoveredWeakRefs[_max_num_q];
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120 _discoveredPhantomRefs = &_discoveredFinalRefs[_max_num_q];
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121
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122 // Initialize all entries to NULL
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123 for (uint i = 0; i < _max_num_q * number_of_subclasses_of_ref(); i++) {
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124 _discovered_refs[i].set_head(NULL);
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125 _discovered_refs[i].set_length(0);
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126 }
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127
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128 setup_policy(false /* default soft ref policy */);
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129 }
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130
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131 #ifndef PRODUCT
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132 void ReferenceProcessor::verify_no_references_recorded() {
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133 guarantee(!_discovering_refs, "Discovering refs?");
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134 for (uint i = 0; i < _max_num_q * number_of_subclasses_of_ref(); i++) {
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135 guarantee(_discovered_refs[i].is_empty(),
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136 "Found non-empty discovered list");
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137 }
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138 }
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139 #endif
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140
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141 void ReferenceProcessor::weak_oops_do(OopClosure* f) {
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142 for (uint i = 0; i < _max_num_q * number_of_subclasses_of_ref(); i++) {
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143 if (UseCompressedOops) {
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144 f->do_oop((narrowOop*)_discovered_refs[i].adr_head());
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145 } else {
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146 f->do_oop((oop*)_discovered_refs[i].adr_head());
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147 }
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148 }
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149 }
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150
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151 void ReferenceProcessor::update_soft_ref_master_clock() {
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152 // Update (advance) the soft ref master clock field. This must be done
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153 // after processing the soft ref list.
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154
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155 // We need a monotonically non-deccreasing time in ms but
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156 // os::javaTimeMillis() does not guarantee monotonicity.
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157 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
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158 jlong soft_ref_clock = java_lang_ref_SoftReference::clock();
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159 assert(soft_ref_clock == _soft_ref_timestamp_clock, "soft ref clocks out of sync");
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160
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161 NOT_PRODUCT(
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162 if (now < _soft_ref_timestamp_clock) {
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163 warning("time warp: "INT64_FORMAT" to "INT64_FORMAT,
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164 _soft_ref_timestamp_clock, now);
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165 }
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166 )
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167 // The values of now and _soft_ref_timestamp_clock are set using
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168 // javaTimeNanos(), which is guaranteed to be monotonically
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169 // non-decreasing provided the underlying platform provides such
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170 // a time source (and it is bug free).
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171 // In product mode, however, protect ourselves from non-monotonicty.
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172 if (now > _soft_ref_timestamp_clock) {
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173 _soft_ref_timestamp_clock = now;
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174 java_lang_ref_SoftReference::set_clock(now);
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175 }
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176 // Else leave clock stalled at its old value until time progresses
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177 // past clock value.
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178 }
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179
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180 size_t ReferenceProcessor::total_count(DiscoveredList lists[]) {
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181 size_t total = 0;
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182 for (uint i = 0; i < _max_num_q; ++i) {
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183 total += lists[i].length();
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184 }
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185 return total;
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186 }
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187
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188 ReferenceProcessorStats ReferenceProcessor::process_discovered_references(
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189 BoolObjectClosure* is_alive,
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190 OopClosure* keep_alive,
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191 VoidClosure* complete_gc,
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192 AbstractRefProcTaskExecutor* task_executor,
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193 GCTimer* gc_timer) {
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194 NOT_PRODUCT(verify_ok_to_handle_reflists());
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195
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196 assert(!enqueuing_is_done(), "If here enqueuing should not be complete");
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197 // Stop treating discovered references specially.
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198 disable_discovery();
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199
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200 // If discovery was concurrent, someone could have modified
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201 // the value of the static field in the j.l.r.SoftReference
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202 // class that holds the soft reference timestamp clock using
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203 // reflection or Unsafe between when discovery was enabled and
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204 // now. Unconditionally update the static field in ReferenceProcessor
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205 // here so that we use the new value during processing of the
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206 // discovered soft refs.
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207
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208 _soft_ref_timestamp_clock = java_lang_ref_SoftReference::clock();
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209
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210 bool trace_time = PrintGCDetails && PrintReferenceGC;
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211
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212 // Soft references
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213 size_t soft_count = 0;
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214 {
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215 GCTraceTime tt("SoftReference", trace_time, false, gc_timer);
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216 soft_count =
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217 process_discovered_reflist(_discoveredSoftRefs, _current_soft_ref_policy, true,
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218 is_alive, keep_alive, complete_gc, task_executor);
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219 }
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220
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221 update_soft_ref_master_clock();
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222
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223 // Weak references
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224 size_t weak_count = 0;
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225 {
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226 GCTraceTime tt("WeakReference", trace_time, false, gc_timer);
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227 weak_count =
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228 process_discovered_reflist(_discoveredWeakRefs, NULL, true,
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229 is_alive, keep_alive, complete_gc, task_executor);
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230 }
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231
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232 // Final references
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233 size_t final_count = 0;
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234 {
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235 GCTraceTime tt("FinalReference", trace_time, false, gc_timer);
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236 final_count =
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237 process_discovered_reflist(_discoveredFinalRefs, NULL, false,
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238 is_alive, keep_alive, complete_gc, task_executor);
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239 }
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240
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241 // Phantom references
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242 size_t phantom_count = 0;
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243 {
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244 GCTraceTime tt("PhantomReference", trace_time, false, gc_timer);
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245 phantom_count =
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246 process_discovered_reflist(_discoveredPhantomRefs, NULL, false,
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247 is_alive, keep_alive, complete_gc, task_executor);
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248 }
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249
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250 // Weak global JNI references. It would make more sense (semantically) to
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251 // traverse these simultaneously with the regular weak references above, but
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252 // that is not how the JDK1.2 specification is. See #4126360. Native code can
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253 // thus use JNI weak references to circumvent the phantom references and
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254 // resurrect a "post-mortem" object.
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255 {
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256 GCTraceTime tt("JNI Weak Reference", trace_time, false, gc_timer);
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257 if (task_executor != NULL) {
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258 task_executor->set_single_threaded_mode();
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259 }
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260 process_phaseJNI(is_alive, keep_alive, complete_gc);
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261 }
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262
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263 return ReferenceProcessorStats(soft_count, weak_count, final_count, phantom_count);
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264 }
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265
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266 #ifndef PRODUCT
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267 // Calculate the number of jni handles.
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268 uint ReferenceProcessor::count_jni_refs() {
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269 class AlwaysAliveClosure: public BoolObjectClosure {
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270 public:
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271 virtual bool do_object_b(oop obj) { return true; }
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272 };
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273
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274 class CountHandleClosure: public OopClosure {
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275 private:
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276 int _count;
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277 public:
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278 CountHandleClosure(): _count(0) {}
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279 void do_oop(oop* unused) { _count++; }
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280 void do_oop(narrowOop* unused) { ShouldNotReachHere(); }
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281 int count() { return _count; }
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282 };
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283 CountHandleClosure global_handle_count;
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284 AlwaysAliveClosure always_alive;
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285 JNIHandles::weak_oops_do(&always_alive, &global_handle_count);
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286 return global_handle_count.count();
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287 }
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288 #endif
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289
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290 void ReferenceProcessor::process_phaseJNI(BoolObjectClosure* is_alive,
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291 OopClosure* keep_alive,
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292 VoidClosure* complete_gc) {
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293 #ifndef PRODUCT
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294 if (PrintGCDetails && PrintReferenceGC) {
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295 unsigned int count = count_jni_refs();
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296 gclog_or_tty->print(", %u refs", count);
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297 }
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298 #endif
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299 JNIHandles::weak_oops_do(is_alive, keep_alive);
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300 complete_gc->do_void();
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301 }
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302
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303
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304 template <class T>
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305 bool enqueue_discovered_ref_helper(ReferenceProcessor* ref,
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306 AbstractRefProcTaskExecutor* task_executor) {
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307
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308 // Remember old value of pending references list
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309 T* pending_list_addr = (T*)java_lang_ref_Reference::pending_list_addr();
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310 T old_pending_list_value = *pending_list_addr;
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311
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312 // Enqueue references that are not made active again, and
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313 // clear the decks for the next collection (cycle).
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314 ref->enqueue_discovered_reflists((HeapWord*)pending_list_addr, task_executor);
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315 // Do the post-barrier on pending_list_addr missed in
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316 // enqueue_discovered_reflist.
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317 oopDesc::bs()->write_ref_field(pending_list_addr, oopDesc::load_decode_heap_oop(pending_list_addr));
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318
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319 // Stop treating discovered references specially.
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320 ref->disable_discovery();
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321
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322 // Return true if new pending references were added
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323 return old_pending_list_value != *pending_list_addr;
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324 }
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325
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326 bool ReferenceProcessor::enqueue_discovered_references(AbstractRefProcTaskExecutor* task_executor) {
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327 NOT_PRODUCT(verify_ok_to_handle_reflists());
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328 if (UseCompressedOops) {
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329 return enqueue_discovered_ref_helper<narrowOop>(this, task_executor);
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330 } else {
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331 return enqueue_discovered_ref_helper<oop>(this, task_executor);
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332 }
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333 }
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334
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335 void ReferenceProcessor::enqueue_discovered_reflist(DiscoveredList& refs_list,
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336 HeapWord* pending_list_addr) {
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337 // Given a list of refs linked through the "discovered" field
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338 // (java.lang.ref.Reference.discovered), self-loop their "next" field
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339 // thus distinguishing them from active References, then
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340 // prepend them to the pending list.
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341 //
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
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342 // The Java threads will see the Reference objects linked together through
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343 // the discovered field. Instead of trying to do the write barrier updates
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344 // in all places in the reference processor where we manipulate the discovered
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345 // field we make sure to do the barrier here where we anyway iterate through
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346 // all linked Reference objects. Note that it is important to not dirty any
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347 // cards during reference processing since this will cause card table
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348 // verification to fail for G1.
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349 //
3917
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350 // BKWRD COMPATIBILITY NOTE: For older JDKs (prior to the fix for 4956777),
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351 // the "next" field is used to chain the pending list, not the discovered
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352 // field.
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353 if (TraceReferenceGC && PrintGCDetails) {
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354 gclog_or_tty->print_cr("ReferenceProcessor::enqueue_discovered_reflist list "
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355 INTPTR_FORMAT, (address)refs_list.head());
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356 }
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357
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358 oop obj = NULL;
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359 oop next_d = refs_list.head();
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360 if (pending_list_uses_discovered_field()) { // New behavior
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361 // Walk down the list, self-looping the next field
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362 // so that the References are not considered active.
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363 while (obj != next_d) {
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364 obj = next_d;
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365 assert(obj->is_instanceRef(), "should be reference object");
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366 next_d = java_lang_ref_Reference::discovered(obj);
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367 if (TraceReferenceGC && PrintGCDetails) {
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368 gclog_or_tty->print_cr(" obj " INTPTR_FORMAT "/next_d " INTPTR_FORMAT,
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369 (void *)obj, (void *)next_d);
3917
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370 }
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371 assert(java_lang_ref_Reference::next(obj) == NULL,
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372 "Reference not active; should not be discovered");
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373 // Self-loop next, so as to make Ref not active.
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374 java_lang_ref_Reference::set_next_raw(obj, obj);
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375 if (next_d != obj) {
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376 oopDesc::bs()->write_ref_field(java_lang_ref_Reference::discovered_addr(obj), next_d);
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377 } else {
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378 // This is the last object.
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379 // Swap refs_list into pending_list_addr and
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380 // set obj's discovered to what we read from pending_list_addr.
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381 oop old = oopDesc::atomic_exchange_oop(refs_list.head(), pending_list_addr);
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382 // Need post-barrier on pending_list_addr. See enqueue_discovered_ref_helper() above.
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383 java_lang_ref_Reference::set_discovered_raw(obj, old); // old may be NULL
fbc1677398c0 8029255: G1: Reference processing should not enqueue references on the shared SATB queue
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384 oopDesc::bs()->write_ref_field(java_lang_ref_Reference::discovered_addr(obj), old);
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385 }
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386 }
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387 } else { // Old behaviour
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388 // Walk down the list, copying the discovered field into
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389 // the next field and clearing the discovered field.
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390 while (obj != next_d) {
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391 obj = next_d;
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392 assert(obj->is_instanceRef(), "should be reference object");
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393 next_d = java_lang_ref_Reference::discovered(obj);
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394 if (TraceReferenceGC && PrintGCDetails) {
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395 gclog_or_tty->print_cr(" obj " INTPTR_FORMAT "/next_d " INTPTR_FORMAT,
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396 (void *)obj, (void *)next_d);
3917
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397 }
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398 assert(java_lang_ref_Reference::next(obj) == NULL,
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
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399 "The reference should not be enqueued");
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400 if (next_d == obj) { // obj is last
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
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diff changeset
401 // Swap refs_list into pendling_list_addr and
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diff changeset
402 // set obj's next to what we read from pending_list_addr.
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403 oop old = oopDesc::atomic_exchange_oop(refs_list.head(), pending_list_addr);
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404 // Need oop_check on pending_list_addr above;
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405 // see special oop-check code at the end of
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diff changeset
406 // enqueue_discovered_reflists() further below.
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
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diff changeset
407 if (old == NULL) {
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
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diff changeset
408 // obj should be made to point to itself, since
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409 // pending list was empty.
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diff changeset
410 java_lang_ref_Reference::set_next(obj, obj);
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diff changeset
411 } else {
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diff changeset
412 java_lang_ref_Reference::set_next(obj, old);
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413 }
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414 } else {
3917
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415 java_lang_ref_Reference::set_next(obj, next_d);
0
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416 }
3917
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diff changeset
417 java_lang_ref_Reference::set_discovered(obj, (oop) NULL);
0
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418 }
a61af66fc99e Initial load
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419 }
a61af66fc99e Initial load
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420 }
a61af66fc99e Initial load
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421
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422 // Parallel enqueue task
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423 class RefProcEnqueueTask: public AbstractRefProcTaskExecutor::EnqueueTask {
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424 public:
a61af66fc99e Initial load
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425 RefProcEnqueueTask(ReferenceProcessor& ref_processor,
a61af66fc99e Initial load
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426 DiscoveredList discovered_refs[],
113
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diff changeset
427 HeapWord* pending_list_addr,
0
a61af66fc99e Initial load
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diff changeset
428 int n_queues)
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429 : EnqueueTask(ref_processor, discovered_refs,
3915
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diff changeset
430 pending_list_addr, n_queues)
0
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431 { }
a61af66fc99e Initial load
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432
113
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diff changeset
433 virtual void work(unsigned int work_id) {
2369
92da084fefc9 6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents: 1995
diff changeset
434 assert(work_id < (unsigned int)_ref_processor.max_num_q(), "Index out-of-bounds");
0
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parents:
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435 // Simplest first cut: static partitioning.
a61af66fc99e Initial load
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diff changeset
436 int index = work_id;
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
437 // The increment on "index" must correspond to the maximum number of queues
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
438 // (n_queues) with which that ReferenceProcessor was created. That
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
439 // is because of the "clever" way the discovered references lists were
2369
92da084fefc9 6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents: 1995
diff changeset
440 // allocated and are indexed into.
92da084fefc9 6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents: 1995
diff changeset
441 assert(_n_queues == (int) _ref_processor.max_num_q(), "Different number not expected");
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
442 for (int j = 0;
3979
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
443 j < ReferenceProcessor::number_of_subclasses_of_ref();
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
444 j++, index += _n_queues) {
0
a61af66fc99e Initial load
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parents:
diff changeset
445 _ref_processor.enqueue_discovered_reflist(
a61af66fc99e Initial load
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parents:
diff changeset
446 _refs_lists[index], _pending_list_addr);
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
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diff changeset
447 _refs_lists[index].set_head(NULL);
0
a61af66fc99e Initial load
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diff changeset
448 _refs_lists[index].set_length(0);
a61af66fc99e Initial load
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449 }
a61af66fc99e Initial load
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parents:
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450 }
a61af66fc99e Initial load
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451 };
a61af66fc99e Initial load
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parents:
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452
a61af66fc99e Initial load
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parents:
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453 // Enqueue references that are not made active again
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
454 void ReferenceProcessor::enqueue_discovered_reflists(HeapWord* pending_list_addr,
0
a61af66fc99e Initial load
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parents:
diff changeset
455 AbstractRefProcTaskExecutor* task_executor) {
a61af66fc99e Initial load
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parents:
diff changeset
456 if (_processing_is_mt && task_executor != NULL) {
a61af66fc99e Initial load
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parents:
diff changeset
457 // Parallel code
4014
bf2d2b8b1726 7095243: Disambiguate ReferenceProcessor::_discoveredSoftRefs
johnc
parents: 3992
diff changeset
458 RefProcEnqueueTask tsk(*this, _discovered_refs,
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
459 pending_list_addr, _max_num_q);
0
a61af66fc99e Initial load
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parents:
diff changeset
460 task_executor->execute(tsk);
a61af66fc99e Initial load
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parents:
diff changeset
461 } else {
a61af66fc99e Initial load
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parents:
diff changeset
462 // Serial code: call the parent class's implementation
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
463 for (uint i = 0; i < _max_num_q * number_of_subclasses_of_ref(); i++) {
4014
bf2d2b8b1726 7095243: Disambiguate ReferenceProcessor::_discoveredSoftRefs
johnc
parents: 3992
diff changeset
464 enqueue_discovered_reflist(_discovered_refs[i], pending_list_addr);
bf2d2b8b1726 7095243: Disambiguate ReferenceProcessor::_discoveredSoftRefs
johnc
parents: 3992
diff changeset
465 _discovered_refs[i].set_head(NULL);
bf2d2b8b1726 7095243: Disambiguate ReferenceProcessor::_discoveredSoftRefs
johnc
parents: 3992
diff changeset
466 _discovered_refs[i].set_length(0);
0
a61af66fc99e Initial load
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parents:
diff changeset
467 }
a61af66fc99e Initial load
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parents:
diff changeset
468 }
a61af66fc99e Initial load
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parents:
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469 }
a61af66fc99e Initial load
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parents:
diff changeset
470
3979
4dfb2df418f2 6484982: G1: process references during evacuation pauses
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parents: 3917
diff changeset
471 void DiscoveredListIterator::load_ptrs(DEBUG_ONLY(bool allow_null_referent)) {
0
a61af66fc99e Initial load
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parents:
diff changeset
472 _discovered_addr = java_lang_ref_Reference::discovered_addr(_ref);
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
473 oop discovered = java_lang_ref_Reference::discovered(_ref);
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
474 assert(_discovered_addr && discovered->is_oop_or_null(),
0
a61af66fc99e Initial load
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parents:
diff changeset
475 "discovered field is bad");
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
476 _next = discovered;
0
a61af66fc99e Initial load
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parents:
diff changeset
477 _referent_addr = java_lang_ref_Reference::referent_addr(_ref);
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
478 _referent = java_lang_ref_Reference::referent(_ref);
0
a61af66fc99e Initial load
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parents:
diff changeset
479 assert(Universe::heap()->is_in_reserved_or_null(_referent),
a61af66fc99e Initial load
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parents:
diff changeset
480 "Wrong oop found in java.lang.Reference object");
a61af66fc99e Initial load
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parents:
diff changeset
481 assert(allow_null_referent ?
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parents:
diff changeset
482 _referent->is_oop_or_null()
a61af66fc99e Initial load
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parents:
diff changeset
483 : _referent->is_oop(),
a61af66fc99e Initial load
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parents:
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484 "bad referent");
a61af66fc99e Initial load
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parents:
diff changeset
485 }
a61af66fc99e Initial load
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parents:
diff changeset
486
3979
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
487 void DiscoveredListIterator::remove() {
0
a61af66fc99e Initial load
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parents:
diff changeset
488 assert(_ref->is_oop(), "Dropping a bad reference");
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
489 oop_store_raw(_discovered_addr, NULL);
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
490
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
491 // First _prev_next ref actually points into DiscoveredList (gross).
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
492 oop new_next;
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
493 if (_next == _ref) {
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
494 // At the end of the list, we should make _prev point to itself.
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
495 // If _ref is the first ref, then _prev_next will be in the DiscoveredList,
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
496 // and _prev will be NULL.
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
497 new_next = _prev;
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
498 } else {
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
499 new_next = _next;
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
500 }
17748
d60ecdb2773e 8031703: Missing post-barrier in ReferenceProcessor
pliden
parents: 14252
diff changeset
501 // Remove Reference object from discovered list. Note that G1 does not need a
d60ecdb2773e 8031703: Missing post-barrier in ReferenceProcessor
pliden
parents: 14252
diff changeset
502 // pre-barrier here because we know the Reference has already been found/marked,
d60ecdb2773e 8031703: Missing post-barrier in ReferenceProcessor
pliden
parents: 14252
diff changeset
503 // that's how it ended up in the discovered list in the first place.
d60ecdb2773e 8031703: Missing post-barrier in ReferenceProcessor
pliden
parents: 14252
diff changeset
504 oop_store_raw(_prev_next, new_next);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
505 NOT_PRODUCT(_removed++);
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
506 _refs_list.dec_length(1);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
507 }
a61af66fc99e Initial load
duke
parents:
diff changeset
508
3979
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
509 // Make the Reference object active again.
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
510 void DiscoveredListIterator::make_active() {
17976
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
brutisso
parents: 17937
diff changeset
511 // The pre barrier for G1 is probably just needed for the old
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
brutisso
parents: 17937
diff changeset
512 // reference processing behavior. Should we guard this with
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
brutisso
parents: 17937
diff changeset
513 // ReferenceProcessor::pending_list_uses_discovered_field() ?
3979
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
514 if (UseG1GC) {
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
515 HeapWord* next_addr = java_lang_ref_Reference::next_addr(_ref);
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
516 if (UseCompressedOops) {
14252
fbc1677398c0 8029255: G1: Reference processing should not enqueue references on the shared SATB queue
pliden
parents: 12316
diff changeset
517 oopDesc::bs()->write_ref_field_pre((narrowOop*)next_addr, NULL);
3979
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
518 } else {
14252
fbc1677398c0 8029255: G1: Reference processing should not enqueue references on the shared SATB queue
pliden
parents: 12316
diff changeset
519 oopDesc::bs()->write_ref_field_pre((oop*)next_addr, NULL);
3979
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
520 }
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
521 }
17976
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
brutisso
parents: 17937
diff changeset
522 java_lang_ref_Reference::set_next_raw(_ref, NULL);
3979
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
523 }
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
524
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
525 void DiscoveredListIterator::clear_referent() {
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
526 oop_store_raw(_referent_addr, NULL);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
527 }
a61af66fc99e Initial load
duke
parents:
diff changeset
528
a61af66fc99e Initial load
duke
parents:
diff changeset
529 // NOTE: process_phase*() are largely similar, and at a high level
a61af66fc99e Initial load
duke
parents:
diff changeset
530 // merely iterate over the extant list applying a predicate to
a61af66fc99e Initial load
duke
parents:
diff changeset
531 // each of its elements and possibly removing that element from the
a61af66fc99e Initial load
duke
parents:
diff changeset
532 // list and applying some further closures to that element.
a61af66fc99e Initial load
duke
parents:
diff changeset
533 // We should consider the possibility of replacing these
a61af66fc99e Initial load
duke
parents:
diff changeset
534 // process_phase*() methods by abstracting them into
a61af66fc99e Initial load
duke
parents:
diff changeset
535 // a single general iterator invocation that receives appropriate
a61af66fc99e Initial load
duke
parents:
diff changeset
536 // closures that accomplish this work.
a61af66fc99e Initial load
duke
parents:
diff changeset
537
a61af66fc99e Initial load
duke
parents:
diff changeset
538 // (SoftReferences only) Traverse the list and remove any SoftReferences whose
a61af66fc99e Initial load
duke
parents:
diff changeset
539 // referents are not alive, but that should be kept alive for policy reasons.
a61af66fc99e Initial load
duke
parents:
diff changeset
540 // Keep alive the transitive closure of all such referents.
a61af66fc99e Initial load
duke
parents:
diff changeset
541 void
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
542 ReferenceProcessor::process_phase1(DiscoveredList& refs_list,
0
a61af66fc99e Initial load
duke
parents:
diff changeset
543 ReferencePolicy* policy,
a61af66fc99e Initial load
duke
parents:
diff changeset
544 BoolObjectClosure* is_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
545 OopClosure* keep_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
546 VoidClosure* complete_gc) {
a61af66fc99e Initial load
duke
parents:
diff changeset
547 assert(policy != NULL, "Must have a non-NULL policy");
17976
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
brutisso
parents: 17937
diff changeset
548 DiscoveredListIterator iter(refs_list, keep_alive, is_alive);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
549 // Decide which softly reachable refs should be kept alive.
a61af66fc99e Initial load
duke
parents:
diff changeset
550 while (iter.has_next()) {
a61af66fc99e Initial load
duke
parents:
diff changeset
551 iter.load_ptrs(DEBUG_ONLY(!discovery_is_atomic() /* allow_null_referent */));
a61af66fc99e Initial load
duke
parents:
diff changeset
552 bool referent_is_dead = (iter.referent() != NULL) && !iter.is_referent_alive();
3992
d1bdeef3e3e2 7098282: G1: assert(interval >= 0) failed: Sanity check, referencePolicy.cpp: 76
johnc
parents: 3979
diff changeset
553 if (referent_is_dead &&
d1bdeef3e3e2 7098282: G1: assert(interval >= 0) failed: Sanity check, referencePolicy.cpp: 76
johnc
parents: 3979
diff changeset
554 !policy->should_clear_reference(iter.obj(), _soft_ref_timestamp_clock)) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
555 if (TraceReferenceGC) {
a61af66fc99e Initial load
duke
parents:
diff changeset
556 gclog_or_tty->print_cr("Dropping reference (" INTPTR_FORMAT ": %s" ") by policy",
12316
190899198332 7195622: CheckUnhandledOops has limited usefulness now
hseigel
parents: 10405
diff changeset
557 (void *)iter.obj(), iter.obj()->klass()->internal_name());
0
a61af66fc99e Initial load
duke
parents:
diff changeset
558 }
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
559 // Remove Reference object from list
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
560 iter.remove();
0
a61af66fc99e Initial load
duke
parents:
diff changeset
561 // Make the Reference object active again
a61af66fc99e Initial load
duke
parents:
diff changeset
562 iter.make_active();
a61af66fc99e Initial load
duke
parents:
diff changeset
563 // keep the referent around
a61af66fc99e Initial load
duke
parents:
diff changeset
564 iter.make_referent_alive();
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
565 iter.move_to_next();
0
a61af66fc99e Initial load
duke
parents:
diff changeset
566 } else {
a61af66fc99e Initial load
duke
parents:
diff changeset
567 iter.next();
a61af66fc99e Initial load
duke
parents:
diff changeset
568 }
a61af66fc99e Initial load
duke
parents:
diff changeset
569 }
a61af66fc99e Initial load
duke
parents:
diff changeset
570 // Close the reachable set
a61af66fc99e Initial load
duke
parents:
diff changeset
571 complete_gc->do_void();
a61af66fc99e Initial load
duke
parents:
diff changeset
572 NOT_PRODUCT(
a61af66fc99e Initial load
duke
parents:
diff changeset
573 if (PrintGCDetails && TraceReferenceGC) {
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
574 gclog_or_tty->print_cr(" Dropped %d dead Refs out of %d "
3917
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
575 "discovered Refs by policy, from list " INTPTR_FORMAT,
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
576 iter.removed(), iter.processed(), (address)refs_list.head());
0
a61af66fc99e Initial load
duke
parents:
diff changeset
577 }
a61af66fc99e Initial load
duke
parents:
diff changeset
578 )
a61af66fc99e Initial load
duke
parents:
diff changeset
579 }
a61af66fc99e Initial load
duke
parents:
diff changeset
580
a61af66fc99e Initial load
duke
parents:
diff changeset
581 // Traverse the list and remove any Refs that are not active, or
a61af66fc99e Initial load
duke
parents:
diff changeset
582 // whose referents are either alive or NULL.
a61af66fc99e Initial load
duke
parents:
diff changeset
583 void
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
584 ReferenceProcessor::pp2_work(DiscoveredList& refs_list,
0
a61af66fc99e Initial load
duke
parents:
diff changeset
585 BoolObjectClosure* is_alive,
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
586 OopClosure* keep_alive) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
587 assert(discovery_is_atomic(), "Error");
17976
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
brutisso
parents: 17937
diff changeset
588 DiscoveredListIterator iter(refs_list, keep_alive, is_alive);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
589 while (iter.has_next()) {
a61af66fc99e Initial load
duke
parents:
diff changeset
590 iter.load_ptrs(DEBUG_ONLY(false /* allow_null_referent */));
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
591 DEBUG_ONLY(oop next = java_lang_ref_Reference::next(iter.obj());)
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
592 assert(next == NULL, "Should not discover inactive Reference");
0
a61af66fc99e Initial load
duke
parents:
diff changeset
593 if (iter.is_referent_alive()) {
a61af66fc99e Initial load
duke
parents:
diff changeset
594 if (TraceReferenceGC) {
a61af66fc99e Initial load
duke
parents:
diff changeset
595 gclog_or_tty->print_cr("Dropping strongly reachable reference (" INTPTR_FORMAT ": %s)",
12316
190899198332 7195622: CheckUnhandledOops has limited usefulness now
hseigel
parents: 10405
diff changeset
596 (void *)iter.obj(), iter.obj()->klass()->internal_name());
0
a61af66fc99e Initial load
duke
parents:
diff changeset
597 }
a61af66fc99e Initial load
duke
parents:
diff changeset
598 // The referent is reachable after all.
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
599 // Remove Reference object from list.
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
600 iter.remove();
0
a61af66fc99e Initial load
duke
parents:
diff changeset
601 // Update the referent pointer as necessary: Note that this
a61af66fc99e Initial load
duke
parents:
diff changeset
602 // should not entail any recursive marking because the
a61af66fc99e Initial load
duke
parents:
diff changeset
603 // referent must already have been traversed.
a61af66fc99e Initial load
duke
parents:
diff changeset
604 iter.make_referent_alive();
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
605 iter.move_to_next();
0
a61af66fc99e Initial load
duke
parents:
diff changeset
606 } else {
a61af66fc99e Initial load
duke
parents:
diff changeset
607 iter.next();
a61af66fc99e Initial load
duke
parents:
diff changeset
608 }
a61af66fc99e Initial load
duke
parents:
diff changeset
609 }
a61af66fc99e Initial load
duke
parents:
diff changeset
610 NOT_PRODUCT(
2369
92da084fefc9 6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents: 1995
diff changeset
611 if (PrintGCDetails && TraceReferenceGC && (iter.processed() > 0)) {
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
612 gclog_or_tty->print_cr(" Dropped %d active Refs out of %d "
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
613 "Refs in discovered list " INTPTR_FORMAT,
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
614 iter.removed(), iter.processed(), (address)refs_list.head());
0
a61af66fc99e Initial load
duke
parents:
diff changeset
615 }
a61af66fc99e Initial load
duke
parents:
diff changeset
616 )
a61af66fc99e Initial load
duke
parents:
diff changeset
617 }
a61af66fc99e Initial load
duke
parents:
diff changeset
618
a61af66fc99e Initial load
duke
parents:
diff changeset
619 void
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
620 ReferenceProcessor::pp2_work_concurrent_discovery(DiscoveredList& refs_list,
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
621 BoolObjectClosure* is_alive,
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
622 OopClosure* keep_alive,
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
623 VoidClosure* complete_gc) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
624 assert(!discovery_is_atomic(), "Error");
17976
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
brutisso
parents: 17937
diff changeset
625 DiscoveredListIterator iter(refs_list, keep_alive, is_alive);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
626 while (iter.has_next()) {
a61af66fc99e Initial load
duke
parents:
diff changeset
627 iter.load_ptrs(DEBUG_ONLY(true /* allow_null_referent */));
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
628 HeapWord* next_addr = java_lang_ref_Reference::next_addr(iter.obj());
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
629 oop next = java_lang_ref_Reference::next(iter.obj());
0
a61af66fc99e Initial load
duke
parents:
diff changeset
630 if ((iter.referent() == NULL || iter.is_referent_alive() ||
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
631 next != NULL)) {
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
632 assert(next->is_oop_or_null(), "bad next field");
0
a61af66fc99e Initial load
duke
parents:
diff changeset
633 // Remove Reference object from list
a61af66fc99e Initial load
duke
parents:
diff changeset
634 iter.remove();
a61af66fc99e Initial load
duke
parents:
diff changeset
635 // Trace the cohorts
a61af66fc99e Initial load
duke
parents:
diff changeset
636 iter.make_referent_alive();
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
637 if (UseCompressedOops) {
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
638 keep_alive->do_oop((narrowOop*)next_addr);
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
639 } else {
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
640 keep_alive->do_oop((oop*)next_addr);
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
641 }
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
642 iter.move_to_next();
0
a61af66fc99e Initial load
duke
parents:
diff changeset
643 } else {
a61af66fc99e Initial load
duke
parents:
diff changeset
644 iter.next();
a61af66fc99e Initial load
duke
parents:
diff changeset
645 }
a61af66fc99e Initial load
duke
parents:
diff changeset
646 }
a61af66fc99e Initial load
duke
parents:
diff changeset
647 // Now close the newly reachable set
a61af66fc99e Initial load
duke
parents:
diff changeset
648 complete_gc->do_void();
a61af66fc99e Initial load
duke
parents:
diff changeset
649 NOT_PRODUCT(
2369
92da084fefc9 6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents: 1995
diff changeset
650 if (PrintGCDetails && TraceReferenceGC && (iter.processed() > 0)) {
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
651 gclog_or_tty->print_cr(" Dropped %d active Refs out of %d "
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
652 "Refs in discovered list " INTPTR_FORMAT,
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
653 iter.removed(), iter.processed(), (address)refs_list.head());
0
a61af66fc99e Initial load
duke
parents:
diff changeset
654 }
a61af66fc99e Initial load
duke
parents:
diff changeset
655 )
a61af66fc99e Initial load
duke
parents:
diff changeset
656 }
a61af66fc99e Initial load
duke
parents:
diff changeset
657
a61af66fc99e Initial load
duke
parents:
diff changeset
658 // Traverse the list and process the referents, by either
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
659 // clearing them or keeping them (and their reachable
0
a61af66fc99e Initial load
duke
parents:
diff changeset
660 // closure) alive.
a61af66fc99e Initial load
duke
parents:
diff changeset
661 void
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
662 ReferenceProcessor::process_phase3(DiscoveredList& refs_list,
0
a61af66fc99e Initial load
duke
parents:
diff changeset
663 bool clear_referent,
a61af66fc99e Initial load
duke
parents:
diff changeset
664 BoolObjectClosure* is_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
665 OopClosure* keep_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
666 VoidClosure* complete_gc) {
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
667 ResourceMark rm;
17976
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
brutisso
parents: 17937
diff changeset
668 DiscoveredListIterator iter(refs_list, keep_alive, is_alive);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
669 while (iter.has_next()) {
a61af66fc99e Initial load
duke
parents:
diff changeset
670 iter.update_discovered();
a61af66fc99e Initial load
duke
parents:
diff changeset
671 iter.load_ptrs(DEBUG_ONLY(false /* allow_null_referent */));
a61af66fc99e Initial load
duke
parents:
diff changeset
672 if (clear_referent) {
a61af66fc99e Initial load
duke
parents:
diff changeset
673 // NULL out referent pointer
a61af66fc99e Initial load
duke
parents:
diff changeset
674 iter.clear_referent();
a61af66fc99e Initial load
duke
parents:
diff changeset
675 } else {
a61af66fc99e Initial load
duke
parents:
diff changeset
676 // keep the referent around
a61af66fc99e Initial load
duke
parents:
diff changeset
677 iter.make_referent_alive();
a61af66fc99e Initial load
duke
parents:
diff changeset
678 }
a61af66fc99e Initial load
duke
parents:
diff changeset
679 if (TraceReferenceGC) {
a61af66fc99e Initial load
duke
parents:
diff changeset
680 gclog_or_tty->print_cr("Adding %sreference (" INTPTR_FORMAT ": %s) as pending",
a61af66fc99e Initial load
duke
parents:
diff changeset
681 clear_referent ? "cleared " : "",
12316
190899198332 7195622: CheckUnhandledOops has limited usefulness now
hseigel
parents: 10405
diff changeset
682 (void *)iter.obj(), iter.obj()->klass()->internal_name());
0
a61af66fc99e Initial load
duke
parents:
diff changeset
683 }
a61af66fc99e Initial load
duke
parents:
diff changeset
684 assert(iter.obj()->is_oop(UseConcMarkSweepGC), "Adding a bad reference");
a61af66fc99e Initial load
duke
parents:
diff changeset
685 iter.next();
a61af66fc99e Initial load
duke
parents:
diff changeset
686 }
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
687 // Remember to update the next pointer of the last ref.
0
a61af66fc99e Initial load
duke
parents:
diff changeset
688 iter.update_discovered();
a61af66fc99e Initial load
duke
parents:
diff changeset
689 // Close the reachable set
a61af66fc99e Initial load
duke
parents:
diff changeset
690 complete_gc->do_void();
a61af66fc99e Initial load
duke
parents:
diff changeset
691 }
a61af66fc99e Initial load
duke
parents:
diff changeset
692
a61af66fc99e Initial load
duke
parents:
diff changeset
693 void
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
694 ReferenceProcessor::clear_discovered_references(DiscoveredList& refs_list) {
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
695 oop obj = NULL;
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
696 oop next = refs_list.head();
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
697 while (next != obj) {
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
698 obj = next;
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
699 next = java_lang_ref_Reference::discovered(obj);
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
700 java_lang_ref_Reference::set_discovered_raw(obj, NULL);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
701 }
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
702 refs_list.set_head(NULL);
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
703 refs_list.set_length(0);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
704 }
a61af66fc99e Initial load
duke
parents:
diff changeset
705
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
706 void
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
707 ReferenceProcessor::abandon_partial_discovered_list(DiscoveredList& refs_list) {
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
708 clear_discovered_references(refs_list);
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
709 }
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
710
342
37f87013dfd8 6711316: Open source the Garbage-First garbage collector
ysr
parents: 113
diff changeset
711 void ReferenceProcessor::abandon_partial_discovery() {
37f87013dfd8 6711316: Open source the Garbage-First garbage collector
ysr
parents: 113
diff changeset
712 // loop over the lists
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
713 for (uint i = 0; i < _max_num_q * number_of_subclasses_of_ref(); i++) {
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
714 if (TraceReferenceGC && PrintGCDetails && ((i % _max_num_q) == 0)) {
3979
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
715 gclog_or_tty->print_cr("\nAbandoning %s discovered list", list_name(i));
342
37f87013dfd8 6711316: Open source the Garbage-First garbage collector
ysr
parents: 113
diff changeset
716 }
4014
bf2d2b8b1726 7095243: Disambiguate ReferenceProcessor::_discoveredSoftRefs
johnc
parents: 3992
diff changeset
717 abandon_partial_discovered_list(_discovered_refs[i]);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
718 }
a61af66fc99e Initial load
duke
parents:
diff changeset
719 }
a61af66fc99e Initial load
duke
parents:
diff changeset
720
a61af66fc99e Initial load
duke
parents:
diff changeset
721 class RefProcPhase1Task: public AbstractRefProcTaskExecutor::ProcessTask {
a61af66fc99e Initial load
duke
parents:
diff changeset
722 public:
a61af66fc99e Initial load
duke
parents:
diff changeset
723 RefProcPhase1Task(ReferenceProcessor& ref_processor,
a61af66fc99e Initial load
duke
parents:
diff changeset
724 DiscoveredList refs_lists[],
a61af66fc99e Initial load
duke
parents:
diff changeset
725 ReferencePolicy* policy,
a61af66fc99e Initial load
duke
parents:
diff changeset
726 bool marks_oops_alive)
a61af66fc99e Initial load
duke
parents:
diff changeset
727 : ProcessTask(ref_processor, refs_lists, marks_oops_alive),
a61af66fc99e Initial load
duke
parents:
diff changeset
728 _policy(policy)
a61af66fc99e Initial load
duke
parents:
diff changeset
729 { }
a61af66fc99e Initial load
duke
parents:
diff changeset
730 virtual void work(unsigned int i, BoolObjectClosure& is_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
731 OopClosure& keep_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
732 VoidClosure& complete_gc)
a61af66fc99e Initial load
duke
parents:
diff changeset
733 {
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
734 Thread* thr = Thread::current();
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
735 int refs_list_index = ((WorkerThread*)thr)->id();
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
736 _ref_processor.process_phase1(_refs_lists[refs_list_index], _policy,
0
a61af66fc99e Initial load
duke
parents:
diff changeset
737 &is_alive, &keep_alive, &complete_gc);
a61af66fc99e Initial load
duke
parents:
diff changeset
738 }
a61af66fc99e Initial load
duke
parents:
diff changeset
739 private:
a61af66fc99e Initial load
duke
parents:
diff changeset
740 ReferencePolicy* _policy;
a61af66fc99e Initial load
duke
parents:
diff changeset
741 };
a61af66fc99e Initial load
duke
parents:
diff changeset
742
a61af66fc99e Initial load
duke
parents:
diff changeset
743 class RefProcPhase2Task: public AbstractRefProcTaskExecutor::ProcessTask {
a61af66fc99e Initial load
duke
parents:
diff changeset
744 public:
a61af66fc99e Initial load
duke
parents:
diff changeset
745 RefProcPhase2Task(ReferenceProcessor& ref_processor,
a61af66fc99e Initial load
duke
parents:
diff changeset
746 DiscoveredList refs_lists[],
a61af66fc99e Initial load
duke
parents:
diff changeset
747 bool marks_oops_alive)
a61af66fc99e Initial load
duke
parents:
diff changeset
748 : ProcessTask(ref_processor, refs_lists, marks_oops_alive)
a61af66fc99e Initial load
duke
parents:
diff changeset
749 { }
a61af66fc99e Initial load
duke
parents:
diff changeset
750 virtual void work(unsigned int i, BoolObjectClosure& is_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
751 OopClosure& keep_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
752 VoidClosure& complete_gc)
a61af66fc99e Initial load
duke
parents:
diff changeset
753 {
a61af66fc99e Initial load
duke
parents:
diff changeset
754 _ref_processor.process_phase2(_refs_lists[i],
a61af66fc99e Initial load
duke
parents:
diff changeset
755 &is_alive, &keep_alive, &complete_gc);
a61af66fc99e Initial load
duke
parents:
diff changeset
756 }
a61af66fc99e Initial load
duke
parents:
diff changeset
757 };
a61af66fc99e Initial load
duke
parents:
diff changeset
758
a61af66fc99e Initial load
duke
parents:
diff changeset
759 class RefProcPhase3Task: public AbstractRefProcTaskExecutor::ProcessTask {
a61af66fc99e Initial load
duke
parents:
diff changeset
760 public:
a61af66fc99e Initial load
duke
parents:
diff changeset
761 RefProcPhase3Task(ReferenceProcessor& ref_processor,
a61af66fc99e Initial load
duke
parents:
diff changeset
762 DiscoveredList refs_lists[],
a61af66fc99e Initial load
duke
parents:
diff changeset
763 bool clear_referent,
a61af66fc99e Initial load
duke
parents:
diff changeset
764 bool marks_oops_alive)
a61af66fc99e Initial load
duke
parents:
diff changeset
765 : ProcessTask(ref_processor, refs_lists, marks_oops_alive),
a61af66fc99e Initial load
duke
parents:
diff changeset
766 _clear_referent(clear_referent)
a61af66fc99e Initial load
duke
parents:
diff changeset
767 { }
a61af66fc99e Initial load
duke
parents:
diff changeset
768 virtual void work(unsigned int i, BoolObjectClosure& is_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
769 OopClosure& keep_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
770 VoidClosure& complete_gc)
a61af66fc99e Initial load
duke
parents:
diff changeset
771 {
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
772 // Don't use "refs_list_index" calculated in this way because
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
773 // balance_queues() has moved the Ref's into the first n queues.
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
774 // Thread* thr = Thread::current();
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
775 // int refs_list_index = ((WorkerThread*)thr)->id();
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
776 // _ref_processor.process_phase3(_refs_lists[refs_list_index], _clear_referent,
0
a61af66fc99e Initial load
duke
parents:
diff changeset
777 _ref_processor.process_phase3(_refs_lists[i], _clear_referent,
a61af66fc99e Initial load
duke
parents:
diff changeset
778 &is_alive, &keep_alive, &complete_gc);
a61af66fc99e Initial load
duke
parents:
diff changeset
779 }
a61af66fc99e Initial load
duke
parents:
diff changeset
780 private:
a61af66fc99e Initial load
duke
parents:
diff changeset
781 bool _clear_referent;
a61af66fc99e Initial load
duke
parents:
diff changeset
782 };
a61af66fc99e Initial load
duke
parents:
diff changeset
783
a61af66fc99e Initial load
duke
parents:
diff changeset
784 // Balances reference queues.
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
785 // Move entries from all queues[0, 1, ..., _max_num_q-1] to
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
786 // queues[0, 1, ..., _num_q-1] because only the first _num_q
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
787 // corresponding to the active workers will be processed.
0
a61af66fc99e Initial load
duke
parents:
diff changeset
788 void ReferenceProcessor::balance_queues(DiscoveredList ref_lists[])
a61af66fc99e Initial load
duke
parents:
diff changeset
789 {
a61af66fc99e Initial load
duke
parents:
diff changeset
790 // calculate total length
a61af66fc99e Initial load
duke
parents:
diff changeset
791 size_t total_refs = 0;
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
792 if (TraceReferenceGC && PrintGCDetails) {
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
793 gclog_or_tty->print_cr("\nBalance ref_lists ");
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
794 }
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
795
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
796 for (uint i = 0; i < _max_num_q; ++i) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
797 total_refs += ref_lists[i].length();
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
798 if (TraceReferenceGC && PrintGCDetails) {
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
799 gclog_or_tty->print("%d ", ref_lists[i].length());
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
800 }
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
801 }
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
802 if (TraceReferenceGC && PrintGCDetails) {
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
803 gclog_or_tty->print_cr(" = %d", total_refs);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
804 }
a61af66fc99e Initial load
duke
parents:
diff changeset
805 size_t avg_refs = total_refs / _num_q + 1;
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
806 uint to_idx = 0;
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
807 for (uint from_idx = 0; from_idx < _max_num_q; from_idx++) {
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
808 bool move_all = false;
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
809 if (from_idx >= _num_q) {
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
810 move_all = ref_lists[from_idx].length() > 0;
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
811 }
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
812 while ((ref_lists[from_idx].length() > avg_refs) ||
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
813 move_all) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
814 assert(to_idx < _num_q, "Sanity Check!");
a61af66fc99e Initial load
duke
parents:
diff changeset
815 if (ref_lists[to_idx].length() < avg_refs) {
a61af66fc99e Initial load
duke
parents:
diff changeset
816 // move superfluous refs
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
817 size_t refs_to_move;
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
818 // Move all the Ref's if the from queue will not be processed.
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
819 if (move_all) {
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
820 refs_to_move = MIN2(ref_lists[from_idx].length(),
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
821 avg_refs - ref_lists[to_idx].length());
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
822 } else {
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
823 refs_to_move = MIN2(ref_lists[from_idx].length() - avg_refs,
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
824 avg_refs - ref_lists[to_idx].length());
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
825 }
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
826
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
827 assert(refs_to_move > 0, "otherwise the code below will fail");
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
828
0
a61af66fc99e Initial load
duke
parents:
diff changeset
829 oop move_head = ref_lists[from_idx].head();
a61af66fc99e Initial load
duke
parents:
diff changeset
830 oop move_tail = move_head;
a61af66fc99e Initial load
duke
parents:
diff changeset
831 oop new_head = move_head;
a61af66fc99e Initial load
duke
parents:
diff changeset
832 // find an element to split the list on
a61af66fc99e Initial load
duke
parents:
diff changeset
833 for (size_t j = 0; j < refs_to_move; ++j) {
a61af66fc99e Initial load
duke
parents:
diff changeset
834 move_tail = new_head;
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
835 new_head = java_lang_ref_Reference::discovered(new_head);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
836 }
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
837
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
838 // Add the chain to the to list.
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
839 if (ref_lists[to_idx].head() == NULL) {
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
840 // to list is empty. Make a loop at the end.
17976
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
brutisso
parents: 17937
diff changeset
841 java_lang_ref_Reference::set_discovered_raw(move_tail, move_tail);
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
842 } else {
17976
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
brutisso
parents: 17937
diff changeset
843 java_lang_ref_Reference::set_discovered_raw(move_tail, ref_lists[to_idx].head());
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
844 }
0
a61af66fc99e Initial load
duke
parents:
diff changeset
845 ref_lists[to_idx].set_head(move_head);
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
846 ref_lists[to_idx].inc_length(refs_to_move);
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
847
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
848 // Remove the chain from the from list.
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
849 if (move_tail == new_head) {
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
850 // We found the end of the from list.
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
851 ref_lists[from_idx].set_head(NULL);
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
852 } else {
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
853 ref_lists[from_idx].set_head(new_head);
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
854 }
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
855 ref_lists[from_idx].dec_length(refs_to_move);
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
856 if (ref_lists[from_idx].length() == 0) {
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
857 break;
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
858 }
0
a61af66fc99e Initial load
duke
parents:
diff changeset
859 } else {
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
860 to_idx = (to_idx + 1) % _num_q;
0
a61af66fc99e Initial load
duke
parents:
diff changeset
861 }
a61af66fc99e Initial load
duke
parents:
diff changeset
862 }
a61af66fc99e Initial load
duke
parents:
diff changeset
863 }
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
864 #ifdef ASSERT
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
865 size_t balanced_total_refs = 0;
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
866 for (uint i = 0; i < _max_num_q; ++i) {
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
867 balanced_total_refs += ref_lists[i].length();
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
868 if (TraceReferenceGC && PrintGCDetails) {
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
869 gclog_or_tty->print("%d ", ref_lists[i].length());
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
870 }
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
871 }
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
872 if (TraceReferenceGC && PrintGCDetails) {
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
873 gclog_or_tty->print_cr(" = %d", balanced_total_refs);
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
874 gclog_or_tty->flush();
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
875 }
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
876 assert(total_refs == balanced_total_refs, "Balancing was incomplete");
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
877 #endif
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
878 }
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
879
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
880 void ReferenceProcessor::balance_all_queues() {
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
881 balance_queues(_discoveredSoftRefs);
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
882 balance_queues(_discoveredWeakRefs);
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
883 balance_queues(_discoveredFinalRefs);
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
884 balance_queues(_discoveredPhantomRefs);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
885 }
a61af66fc99e Initial load
duke
parents:
diff changeset
886
10405
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
887 size_t
0
a61af66fc99e Initial load
duke
parents:
diff changeset
888 ReferenceProcessor::process_discovered_reflist(
a61af66fc99e Initial load
duke
parents:
diff changeset
889 DiscoveredList refs_lists[],
a61af66fc99e Initial load
duke
parents:
diff changeset
890 ReferencePolicy* policy,
a61af66fc99e Initial load
duke
parents:
diff changeset
891 bool clear_referent,
a61af66fc99e Initial load
duke
parents:
diff changeset
892 BoolObjectClosure* is_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
893 OopClosure* keep_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
894 VoidClosure* complete_gc,
a61af66fc99e Initial load
duke
parents:
diff changeset
895 AbstractRefProcTaskExecutor* task_executor)
a61af66fc99e Initial load
duke
parents:
diff changeset
896 {
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
897 bool mt_processing = task_executor != NULL && _processing_is_mt;
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
898 // If discovery used MT and a dynamic number of GC threads, then
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
899 // the queues must be balanced for correctness if fewer than the
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
900 // maximum number of queues were used. The number of queue used
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
901 // during discovery may be different than the number to be used
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
902 // for processing so don't depend of _num_q < _max_num_q as part
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
903 // of the test.
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
904 bool must_balance = _discovery_is_mt;
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
905
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
906 if ((mt_processing && ParallelRefProcBalancingEnabled) ||
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
907 must_balance) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
908 balance_queues(refs_lists);
a61af66fc99e Initial load
duke
parents:
diff changeset
909 }
10405
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
910
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
911 size_t total_list_count = total_count(refs_lists);
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
912
0
a61af66fc99e Initial load
duke
parents:
diff changeset
913 if (PrintReferenceGC && PrintGCDetails) {
10405
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
914 gclog_or_tty->print(", %u refs", total_list_count);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
915 }
a61af66fc99e Initial load
duke
parents:
diff changeset
916
a61af66fc99e Initial load
duke
parents:
diff changeset
917 // Phase 1 (soft refs only):
a61af66fc99e Initial load
duke
parents:
diff changeset
918 // . Traverse the list and remove any SoftReferences whose
a61af66fc99e Initial load
duke
parents:
diff changeset
919 // referents are not alive, but that should be kept alive for
a61af66fc99e Initial load
duke
parents:
diff changeset
920 // policy reasons. Keep alive the transitive closure of all
a61af66fc99e Initial load
duke
parents:
diff changeset
921 // such referents.
a61af66fc99e Initial load
duke
parents:
diff changeset
922 if (policy != NULL) {
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
923 if (mt_processing) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
924 RefProcPhase1Task phase1(*this, refs_lists, policy, true /*marks_oops_alive*/);
a61af66fc99e Initial load
duke
parents:
diff changeset
925 task_executor->execute(phase1);
a61af66fc99e Initial load
duke
parents:
diff changeset
926 } else {
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
927 for (uint i = 0; i < _max_num_q; i++) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
928 process_phase1(refs_lists[i], policy,
a61af66fc99e Initial load
duke
parents:
diff changeset
929 is_alive, keep_alive, complete_gc);
a61af66fc99e Initial load
duke
parents:
diff changeset
930 }
a61af66fc99e Initial load
duke
parents:
diff changeset
931 }
a61af66fc99e Initial load
duke
parents:
diff changeset
932 } else { // policy == NULL
a61af66fc99e Initial load
duke
parents:
diff changeset
933 assert(refs_lists != _discoveredSoftRefs,
a61af66fc99e Initial load
duke
parents:
diff changeset
934 "Policy must be specified for soft references.");
a61af66fc99e Initial load
duke
parents:
diff changeset
935 }
a61af66fc99e Initial load
duke
parents:
diff changeset
936
a61af66fc99e Initial load
duke
parents:
diff changeset
937 // Phase 2:
a61af66fc99e Initial load
duke
parents:
diff changeset
938 // . Traverse the list and remove any refs whose referents are alive.
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
939 if (mt_processing) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
940 RefProcPhase2Task phase2(*this, refs_lists, !discovery_is_atomic() /*marks_oops_alive*/);
a61af66fc99e Initial load
duke
parents:
diff changeset
941 task_executor->execute(phase2);
a61af66fc99e Initial load
duke
parents:
diff changeset
942 } else {
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
943 for (uint i = 0; i < _max_num_q; i++) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
944 process_phase2(refs_lists[i], is_alive, keep_alive, complete_gc);
a61af66fc99e Initial load
duke
parents:
diff changeset
945 }
a61af66fc99e Initial load
duke
parents:
diff changeset
946 }
a61af66fc99e Initial load
duke
parents:
diff changeset
947
a61af66fc99e Initial load
duke
parents:
diff changeset
948 // Phase 3:
a61af66fc99e Initial load
duke
parents:
diff changeset
949 // . Traverse the list and process referents as appropriate.
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
950 if (mt_processing) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
951 RefProcPhase3Task phase3(*this, refs_lists, clear_referent, true /*marks_oops_alive*/);
a61af66fc99e Initial load
duke
parents:
diff changeset
952 task_executor->execute(phase3);
a61af66fc99e Initial load
duke
parents:
diff changeset
953 } else {
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
954 for (uint i = 0; i < _max_num_q; i++) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
955 process_phase3(refs_lists[i], clear_referent,
a61af66fc99e Initial load
duke
parents:
diff changeset
956 is_alive, keep_alive, complete_gc);
a61af66fc99e Initial load
duke
parents:
diff changeset
957 }
a61af66fc99e Initial load
duke
parents:
diff changeset
958 }
10405
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
959
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
960 return total_list_count;
0
a61af66fc99e Initial load
duke
parents:
diff changeset
961 }
a61af66fc99e Initial load
duke
parents:
diff changeset
962
a61af66fc99e Initial load
duke
parents:
diff changeset
963 void ReferenceProcessor::clean_up_discovered_references() {
a61af66fc99e Initial load
duke
parents:
diff changeset
964 // loop over the lists
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
965 for (uint i = 0; i < _max_num_q * number_of_subclasses_of_ref(); i++) {
2369
92da084fefc9 6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents: 1995
diff changeset
966 if (TraceReferenceGC && PrintGCDetails && ((i % _max_num_q) == 0)) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
967 gclog_or_tty->print_cr(
a61af66fc99e Initial load
duke
parents:
diff changeset
968 "\nScrubbing %s discovered list of Null referents",
a61af66fc99e Initial load
duke
parents:
diff changeset
969 list_name(i));
a61af66fc99e Initial load
duke
parents:
diff changeset
970 }
4014
bf2d2b8b1726 7095243: Disambiguate ReferenceProcessor::_discoveredSoftRefs
johnc
parents: 3992
diff changeset
971 clean_up_discovered_reflist(_discovered_refs[i]);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
972 }
a61af66fc99e Initial load
duke
parents:
diff changeset
973 }
a61af66fc99e Initial load
duke
parents:
diff changeset
974
a61af66fc99e Initial load
duke
parents:
diff changeset
975 void ReferenceProcessor::clean_up_discovered_reflist(DiscoveredList& refs_list) {
a61af66fc99e Initial load
duke
parents:
diff changeset
976 assert(!discovery_is_atomic(), "Else why call this method?");
17976
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
brutisso
parents: 17937
diff changeset
977 DiscoveredListIterator iter(refs_list, NULL, NULL);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
978 while (iter.has_next()) {
a61af66fc99e Initial load
duke
parents:
diff changeset
979 iter.load_ptrs(DEBUG_ONLY(true /* allow_null_referent */));
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
980 oop next = java_lang_ref_Reference::next(iter.obj());
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
981 assert(next->is_oop_or_null(), "bad next field");
0
a61af66fc99e Initial load
duke
parents:
diff changeset
982 // If referent has been cleared or Reference is not active,
a61af66fc99e Initial load
duke
parents:
diff changeset
983 // drop it.
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
984 if (iter.referent() == NULL || next != NULL) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
985 debug_only(
a61af66fc99e Initial load
duke
parents:
diff changeset
986 if (PrintGCDetails && TraceReferenceGC) {
a61af66fc99e Initial load
duke
parents:
diff changeset
987 gclog_or_tty->print_cr("clean_up_discovered_list: Dropping Reference: "
a61af66fc99e Initial load
duke
parents:
diff changeset
988 INTPTR_FORMAT " with next field: " INTPTR_FORMAT
a61af66fc99e Initial load
duke
parents:
diff changeset
989 " and referent: " INTPTR_FORMAT,
12316
190899198332 7195622: CheckUnhandledOops has limited usefulness now
hseigel
parents: 10405
diff changeset
990 (void *)iter.obj(), (void *)next, (void *)iter.referent());
0
a61af66fc99e Initial load
duke
parents:
diff changeset
991 }
a61af66fc99e Initial load
duke
parents:
diff changeset
992 )
a61af66fc99e Initial load
duke
parents:
diff changeset
993 // Remove Reference object from list
a61af66fc99e Initial load
duke
parents:
diff changeset
994 iter.remove();
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
995 iter.move_to_next();
0
a61af66fc99e Initial load
duke
parents:
diff changeset
996 } else {
a61af66fc99e Initial load
duke
parents:
diff changeset
997 iter.next();
a61af66fc99e Initial load
duke
parents:
diff changeset
998 }
a61af66fc99e Initial load
duke
parents:
diff changeset
999 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1000 NOT_PRODUCT(
a61af66fc99e Initial load
duke
parents:
diff changeset
1001 if (PrintGCDetails && TraceReferenceGC) {
a61af66fc99e Initial load
duke
parents:
diff changeset
1002 gclog_or_tty->print(
a61af66fc99e Initial load
duke
parents:
diff changeset
1003 " Removed %d Refs with NULL referents out of %d discovered Refs",
a61af66fc99e Initial load
duke
parents:
diff changeset
1004 iter.removed(), iter.processed());
a61af66fc99e Initial load
duke
parents:
diff changeset
1005 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1006 )
a61af66fc99e Initial load
duke
parents:
diff changeset
1007 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1008
a61af66fc99e Initial load
duke
parents:
diff changeset
1009 inline DiscoveredList* ReferenceProcessor::get_discovered_list(ReferenceType rt) {
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
1010 uint id = 0;
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1011 // Determine the queue index to use for this object.
a61af66fc99e Initial load
duke
parents:
diff changeset
1012 if (_discovery_is_mt) {
a61af66fc99e Initial load
duke
parents:
diff changeset
1013 // During a multi-threaded discovery phase,
a61af66fc99e Initial load
duke
parents:
diff changeset
1014 // each thread saves to its "own" list.
a61af66fc99e Initial load
duke
parents:
diff changeset
1015 Thread* thr = Thread::current();
1974
fd1d227ef1b9 6983204: G1: Nightly test nsk/regression/b4958615 failing with +ExplicitGCInvokesConcurrent
johnc
parents: 1972
diff changeset
1016 id = thr->as_Worker_thread()->id();
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1017 } else {
a61af66fc99e Initial load
duke
parents:
diff changeset
1018 // single-threaded discovery, we save in round-robin
a61af66fc99e Initial load
duke
parents:
diff changeset
1019 // fashion to each of the lists.
a61af66fc99e Initial load
duke
parents:
diff changeset
1020 if (_processing_is_mt) {
a61af66fc99e Initial load
duke
parents:
diff changeset
1021 id = next_id();
a61af66fc99e Initial load
duke
parents:
diff changeset
1022 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1023 }
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
1024 assert(0 <= id && id < _max_num_q, "Id is out-of-bounds (call Freud?)");
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1025
a61af66fc99e Initial load
duke
parents:
diff changeset
1026 // Get the discovered queue to which we will add
a61af66fc99e Initial load
duke
parents:
diff changeset
1027 DiscoveredList* list = NULL;
a61af66fc99e Initial load
duke
parents:
diff changeset
1028 switch (rt) {
a61af66fc99e Initial load
duke
parents:
diff changeset
1029 case REF_OTHER:
a61af66fc99e Initial load
duke
parents:
diff changeset
1030 // Unknown reference type, no special treatment
a61af66fc99e Initial load
duke
parents:
diff changeset
1031 break;
a61af66fc99e Initial load
duke
parents:
diff changeset
1032 case REF_SOFT:
a61af66fc99e Initial load
duke
parents:
diff changeset
1033 list = &_discoveredSoftRefs[id];
a61af66fc99e Initial load
duke
parents:
diff changeset
1034 break;
a61af66fc99e Initial load
duke
parents:
diff changeset
1035 case REF_WEAK:
a61af66fc99e Initial load
duke
parents:
diff changeset
1036 list = &_discoveredWeakRefs[id];
a61af66fc99e Initial load
duke
parents:
diff changeset
1037 break;
a61af66fc99e Initial load
duke
parents:
diff changeset
1038 case REF_FINAL:
a61af66fc99e Initial load
duke
parents:
diff changeset
1039 list = &_discoveredFinalRefs[id];
a61af66fc99e Initial load
duke
parents:
diff changeset
1040 break;
a61af66fc99e Initial load
duke
parents:
diff changeset
1041 case REF_PHANTOM:
a61af66fc99e Initial load
duke
parents:
diff changeset
1042 list = &_discoveredPhantomRefs[id];
a61af66fc99e Initial load
duke
parents:
diff changeset
1043 break;
a61af66fc99e Initial load
duke
parents:
diff changeset
1044 case REF_NONE:
6735
aed758eda82a 7195833: NPG: Rename instanceClassLoaderKlass, instanceRefKlass and instanceMirrorKlass
coleenp
parents: 6725
diff changeset
1045 // we should not reach here if we are an InstanceRefKlass
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1046 default:
a61af66fc99e Initial load
duke
parents:
diff changeset
1047 ShouldNotReachHere();
a61af66fc99e Initial load
duke
parents:
diff changeset
1048 }
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
1049 if (TraceReferenceGC && PrintGCDetails) {
1974
fd1d227ef1b9 6983204: G1: Nightly test nsk/regression/b4958615 failing with +ExplicitGCInvokesConcurrent
johnc
parents: 1972
diff changeset
1050 gclog_or_tty->print_cr("Thread %d gets list " INTPTR_FORMAT, id, list);
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
1051 }
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1052 return list;
a61af66fc99e Initial load
duke
parents:
diff changeset
1053 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1054
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1055 inline void
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1056 ReferenceProcessor::add_to_discovered_list_mt(DiscoveredList& refs_list,
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1057 oop obj,
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1058 HeapWord* discovered_addr) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1059 assert(_discovery_is_mt, "!_discovery_is_mt should have been handled by caller");
a61af66fc99e Initial load
duke
parents:
diff changeset
1060 // First we must make sure this object is only enqueued once. CAS in a non null
a61af66fc99e Initial load
duke
parents:
diff changeset
1061 // discovered_addr.
342
37f87013dfd8 6711316: Open source the Garbage-First garbage collector
ysr
parents: 113
diff changeset
1062 oop current_head = refs_list.head();
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
1063 // The last ref must have its discovered field pointing to itself.
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
1064 oop next_discovered = (current_head != NULL) ? current_head : obj;
342
37f87013dfd8 6711316: Open source the Garbage-First garbage collector
ysr
parents: 113
diff changeset
1065
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
1066 oop retest = oopDesc::atomic_compare_exchange_oop(next_discovered, discovered_addr,
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1067 NULL);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1068 if (retest == NULL) {
a61af66fc99e Initial load
duke
parents:
diff changeset
1069 // This thread just won the right to enqueue the object.
3917
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1070 // We have separate lists for enqueueing, so no synchronization
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1071 // is necessary.
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1072 refs_list.set_head(obj);
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1073 refs_list.inc_length(1);
1974
fd1d227ef1b9 6983204: G1: Nightly test nsk/regression/b4958615 failing with +ExplicitGCInvokesConcurrent
johnc
parents: 1972
diff changeset
1074
fd1d227ef1b9 6983204: G1: Nightly test nsk/regression/b4958615 failing with +ExplicitGCInvokesConcurrent
johnc
parents: 1972
diff changeset
1075 if (TraceReferenceGC) {
3917
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1076 gclog_or_tty->print_cr("Discovered reference (mt) (" INTPTR_FORMAT ": %s)",
12316
190899198332 7195622: CheckUnhandledOops has limited usefulness now
hseigel
parents: 10405
diff changeset
1077 (void *)obj, obj->klass()->internal_name());
1974
fd1d227ef1b9 6983204: G1: Nightly test nsk/regression/b4958615 failing with +ExplicitGCInvokesConcurrent
johnc
parents: 1972
diff changeset
1078 }
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1079 } else {
a61af66fc99e Initial load
duke
parents:
diff changeset
1080 // If retest was non NULL, another thread beat us to it:
a61af66fc99e Initial load
duke
parents:
diff changeset
1081 // The reference has already been discovered...
a61af66fc99e Initial load
duke
parents:
diff changeset
1082 if (TraceReferenceGC) {
3917
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1083 gclog_or_tty->print_cr("Already discovered reference (" INTPTR_FORMAT ": %s)",
12316
190899198332 7195622: CheckUnhandledOops has limited usefulness now
hseigel
parents: 10405
diff changeset
1084 (void *)obj, obj->klass()->internal_name());
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1085 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1086 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1087 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1088
1995
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1089 #ifndef PRODUCT
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1090 // Non-atomic (i.e. concurrent) discovery might allow us
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1091 // to observe j.l.References with NULL referents, being those
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1092 // cleared concurrently by mutators during (or after) discovery.
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1093 void ReferenceProcessor::verify_referent(oop obj) {
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1094 bool da = discovery_is_atomic();
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1095 oop referent = java_lang_ref_Reference::referent(obj);
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1096 assert(da ? referent->is_oop() : referent->is_oop_or_null(),
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1097 err_msg("Bad referent " INTPTR_FORMAT " found in Reference "
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1098 INTPTR_FORMAT " during %satomic discovery ",
12316
190899198332 7195622: CheckUnhandledOops has limited usefulness now
hseigel
parents: 10405
diff changeset
1099 (void *)referent, (void *)obj, da ? "" : "non-"));
1995
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1100 }
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1101 #endif
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1102
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1103 // We mention two of several possible choices here:
a61af66fc99e Initial load
duke
parents:
diff changeset
1104 // #0: if the reference object is not in the "originating generation"
a61af66fc99e Initial load
duke
parents:
diff changeset
1105 // (or part of the heap being collected, indicated by our "span"
a61af66fc99e Initial load
duke
parents:
diff changeset
1106 // we don't treat it specially (i.e. we scan it as we would
a61af66fc99e Initial load
duke
parents:
diff changeset
1107 // a normal oop, treating its references as strong references).
3917
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1108 // This means that references can't be discovered unless their
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1109 // referent is also in the same span. This is the simplest,
a61af66fc99e Initial load
duke
parents:
diff changeset
1110 // most "local" and most conservative approach, albeit one
a61af66fc99e Initial load
duke
parents:
diff changeset
1111 // that may cause weak references to be enqueued least promptly.
a61af66fc99e Initial load
duke
parents:
diff changeset
1112 // We call this choice the "ReferenceBasedDiscovery" policy.
a61af66fc99e Initial load
duke
parents:
diff changeset
1113 // #1: the reference object may be in any generation (span), but if
a61af66fc99e Initial load
duke
parents:
diff changeset
1114 // the referent is in the generation (span) being currently collected
a61af66fc99e Initial load
duke
parents:
diff changeset
1115 // then we can discover the reference object, provided
a61af66fc99e Initial load
duke
parents:
diff changeset
1116 // the object has not already been discovered by
a61af66fc99e Initial load
duke
parents:
diff changeset
1117 // a different concurrently running collector (as may be the
a61af66fc99e Initial load
duke
parents:
diff changeset
1118 // case, for instance, if the reference object is in CMS and
a61af66fc99e Initial load
duke
parents:
diff changeset
1119 // the referent in DefNewGeneration), and provided the processing
a61af66fc99e Initial load
duke
parents:
diff changeset
1120 // of this reference object by the current collector will
a61af66fc99e Initial load
duke
parents:
diff changeset
1121 // appear atomic to every other collector in the system.
a61af66fc99e Initial load
duke
parents:
diff changeset
1122 // (Thus, for instance, a concurrent collector may not
a61af66fc99e Initial load
duke
parents:
diff changeset
1123 // discover references in other generations even if the
a61af66fc99e Initial load
duke
parents:
diff changeset
1124 // referent is in its own generation). This policy may,
a61af66fc99e Initial load
duke
parents:
diff changeset
1125 // in certain cases, enqueue references somewhat sooner than
a61af66fc99e Initial load
duke
parents:
diff changeset
1126 // might Policy #0 above, but at marginally increased cost
a61af66fc99e Initial load
duke
parents:
diff changeset
1127 // and complexity in processing these references.
a61af66fc99e Initial load
duke
parents:
diff changeset
1128 // We call this choice the "RefeferentBasedDiscovery" policy.
a61af66fc99e Initial load
duke
parents:
diff changeset
1129 bool ReferenceProcessor::discover_reference(oop obj, ReferenceType rt) {
3917
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1130 // Make sure we are discovering refs (rather than processing discovered refs).
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1131 if (!_discovering_refs || !RegisterReferences) {
a61af66fc99e Initial load
duke
parents:
diff changeset
1132 return false;
a61af66fc99e Initial load
duke
parents:
diff changeset
1133 }
3917
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1134 // We only discover active references.
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1135 oop next = java_lang_ref_Reference::next(obj);
3917
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1136 if (next != NULL) { // Ref is no longer active
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1137 return false;
a61af66fc99e Initial load
duke
parents:
diff changeset
1138 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1139
a61af66fc99e Initial load
duke
parents:
diff changeset
1140 HeapWord* obj_addr = (HeapWord*)obj;
a61af66fc99e Initial load
duke
parents:
diff changeset
1141 if (RefDiscoveryPolicy == ReferenceBasedDiscovery &&
a61af66fc99e Initial load
duke
parents:
diff changeset
1142 !_span.contains(obj_addr)) {
a61af66fc99e Initial load
duke
parents:
diff changeset
1143 // Reference is not in the originating generation;
a61af66fc99e Initial load
duke
parents:
diff changeset
1144 // don't treat it specially (i.e. we want to scan it as a normal
a61af66fc99e Initial load
duke
parents:
diff changeset
1145 // object with strong references).
a61af66fc99e Initial load
duke
parents:
diff changeset
1146 return false;
a61af66fc99e Initial load
duke
parents:
diff changeset
1147 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1148
3917
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1149 // We only discover references whose referents are not (yet)
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1150 // known to be strongly reachable.
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1151 if (is_alive_non_header() != NULL) {
1995
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1152 verify_referent(obj);
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1153 if (is_alive_non_header()->do_object_b(java_lang_ref_Reference::referent(obj))) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1154 return false; // referent is reachable
a61af66fc99e Initial load
duke
parents:
diff changeset
1155 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1156 }
453
c96030fff130 6684579: SoftReference processing can be made more efficient
ysr
parents: 452
diff changeset
1157 if (rt == REF_SOFT) {
c96030fff130 6684579: SoftReference processing can be made more efficient
ysr
parents: 452
diff changeset
1158 // For soft refs we can decide now if these are not
c96030fff130 6684579: SoftReference processing can be made more efficient
ysr
parents: 452
diff changeset
1159 // current candidates for clearing, in which case we
c96030fff130 6684579: SoftReference processing can be made more efficient
ysr
parents: 452
diff changeset
1160 // can mark through them now, rather than delaying that
c96030fff130 6684579: SoftReference processing can be made more efficient
ysr
parents: 452
diff changeset
1161 // to the reference-processing phase. Since all current
c96030fff130 6684579: SoftReference processing can be made more efficient
ysr
parents: 452
diff changeset
1162 // time-stamp policies advance the soft-ref clock only
c96030fff130 6684579: SoftReference processing can be made more efficient
ysr
parents: 452
diff changeset
1163 // at a major collection cycle, this is always currently
c96030fff130 6684579: SoftReference processing can be made more efficient
ysr
parents: 452
diff changeset
1164 // accurate.
3992
d1bdeef3e3e2 7098282: G1: assert(interval >= 0) failed: Sanity check, referencePolicy.cpp: 76
johnc
parents: 3979
diff changeset
1165 if (!_current_soft_ref_policy->should_clear_reference(obj, _soft_ref_timestamp_clock)) {
453
c96030fff130 6684579: SoftReference processing can be made more efficient
ysr
parents: 452
diff changeset
1166 return false;
c96030fff130 6684579: SoftReference processing can be made more efficient
ysr
parents: 452
diff changeset
1167 }
c96030fff130 6684579: SoftReference processing can be made more efficient
ysr
parents: 452
diff changeset
1168 }
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1169
3979
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
1170 ResourceMark rm; // Needed for tracing.
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
1171
342
37f87013dfd8 6711316: Open source the Garbage-First garbage collector
ysr
parents: 113
diff changeset
1172 HeapWord* const discovered_addr = java_lang_ref_Reference::discovered_addr(obj);
37f87013dfd8 6711316: Open source the Garbage-First garbage collector
ysr
parents: 113
diff changeset
1173 const oop discovered = java_lang_ref_Reference::discovered(obj);
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1174 assert(discovered->is_oop_or_null(), "bad discovered field");
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1175 if (discovered != NULL) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1176 // The reference has already been discovered...
a61af66fc99e Initial load
duke
parents:
diff changeset
1177 if (TraceReferenceGC) {
3917
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1178 gclog_or_tty->print_cr("Already discovered reference (" INTPTR_FORMAT ": %s)",
12316
190899198332 7195622: CheckUnhandledOops has limited usefulness now
hseigel
parents: 10405
diff changeset
1179 (void *)obj, obj->klass()->internal_name());
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1180 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1181 if (RefDiscoveryPolicy == ReferentBasedDiscovery) {
a61af66fc99e Initial load
duke
parents:
diff changeset
1182 // assumes that an object is not processed twice;
a61af66fc99e Initial load
duke
parents:
diff changeset
1183 // if it's been already discovered it must be on another
a61af66fc99e Initial load
duke
parents:
diff changeset
1184 // generation's discovered list; so we won't discover it.
a61af66fc99e Initial load
duke
parents:
diff changeset
1185 return false;
a61af66fc99e Initial load
duke
parents:
diff changeset
1186 } else {
a61af66fc99e Initial load
duke
parents:
diff changeset
1187 assert(RefDiscoveryPolicy == ReferenceBasedDiscovery,
a61af66fc99e Initial load
duke
parents:
diff changeset
1188 "Unrecognized policy");
a61af66fc99e Initial load
duke
parents:
diff changeset
1189 // Check assumption that an object is not potentially
a61af66fc99e Initial load
duke
parents:
diff changeset
1190 // discovered twice except by concurrent collectors that potentially
a61af66fc99e Initial load
duke
parents:
diff changeset
1191 // trace the same Reference object twice.
1974
fd1d227ef1b9 6983204: G1: Nightly test nsk/regression/b4958615 failing with +ExplicitGCInvokesConcurrent
johnc
parents: 1972
diff changeset
1192 assert(UseConcMarkSweepGC || UseG1GC,
fd1d227ef1b9 6983204: G1: Nightly test nsk/regression/b4958615 failing with +ExplicitGCInvokesConcurrent
johnc
parents: 1972
diff changeset
1193 "Only possible with a concurrent marking collector");
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1194 return true;
a61af66fc99e Initial load
duke
parents:
diff changeset
1195 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1196 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1197
a61af66fc99e Initial load
duke
parents:
diff changeset
1198 if (RefDiscoveryPolicy == ReferentBasedDiscovery) {
1995
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1199 verify_referent(obj);
3917
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1200 // Discover if and only if EITHER:
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1201 // .. reference is in our span, OR
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1202 // .. we are an atomic collector and referent is in our span
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1203 if (_span.contains(obj_addr) ||
1995
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1204 (discovery_is_atomic() &&
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1205 _span.contains(java_lang_ref_Reference::referent(obj)))) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1206 // should_enqueue = true;
a61af66fc99e Initial load
duke
parents:
diff changeset
1207 } else {
a61af66fc99e Initial load
duke
parents:
diff changeset
1208 return false;
a61af66fc99e Initial load
duke
parents:
diff changeset
1209 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1210 } else {
a61af66fc99e Initial load
duke
parents:
diff changeset
1211 assert(RefDiscoveryPolicy == ReferenceBasedDiscovery &&
a61af66fc99e Initial load
duke
parents:
diff changeset
1212 _span.contains(obj_addr), "code inconsistency");
a61af66fc99e Initial load
duke
parents:
diff changeset
1213 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1214
a61af66fc99e Initial load
duke
parents:
diff changeset
1215 // Get the right type of discovered queue head.
a61af66fc99e Initial load
duke
parents:
diff changeset
1216 DiscoveredList* list = get_discovered_list(rt);
a61af66fc99e Initial load
duke
parents:
diff changeset
1217 if (list == NULL) {
a61af66fc99e Initial load
duke
parents:
diff changeset
1218 return false; // nothing special needs to be done
a61af66fc99e Initial load
duke
parents:
diff changeset
1219 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1220
a61af66fc99e Initial load
duke
parents:
diff changeset
1221 if (_discovery_is_mt) {
a61af66fc99e Initial load
duke
parents:
diff changeset
1222 add_to_discovered_list_mt(*list, obj, discovered_addr);
a61af66fc99e Initial load
duke
parents:
diff changeset
1223 } else {
17976
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
brutisso
parents: 17937
diff changeset
1224 // We do a raw store here: the field will be visited later when processing
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
brutisso
parents: 17937
diff changeset
1225 // the discovered references.
342
37f87013dfd8 6711316: Open source the Garbage-First garbage collector
ysr
parents: 113
diff changeset
1226 oop current_head = list->head();
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
1227 // The last ref must have its discovered field pointing to itself.
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
1228 oop next_discovered = (current_head != NULL) ? current_head : obj;
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
1229
342
37f87013dfd8 6711316: Open source the Garbage-First garbage collector
ysr
parents: 113
diff changeset
1230 assert(discovered == NULL, "control point invariant");
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
1231 oop_store_raw(discovered_addr, next_discovered);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1232 list->set_head(obj);
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1233 list->inc_length(1);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1234
1974
fd1d227ef1b9 6983204: G1: Nightly test nsk/regression/b4958615 failing with +ExplicitGCInvokesConcurrent
johnc
parents: 1972
diff changeset
1235 if (TraceReferenceGC) {
3917
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1236 gclog_or_tty->print_cr("Discovered reference (" INTPTR_FORMAT ": %s)",
12316
190899198332 7195622: CheckUnhandledOops has limited usefulness now
hseigel
parents: 10405
diff changeset
1237 (void *)obj, obj->klass()->internal_name());
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1238 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1239 }
3917
eca1193ca245 4965777: GC changes to support use of discovered field for pending references
ysr
parents: 3915
diff changeset
1240 assert(obj->is_oop(), "Discovered a bad reference");
1995
8df09fb45352 7005259: CMS: BubbleUpRef asserts referent(obj)->is_oop() failed: Enqueued a bad referent
ysr
parents: 1974
diff changeset
1241 verify_referent(obj);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1242 return true;
a61af66fc99e Initial load
duke
parents:
diff changeset
1243 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1244
a61af66fc99e Initial load
duke
parents:
diff changeset
1245 // Preclean the discovered references by removing those
a61af66fc99e Initial load
duke
parents:
diff changeset
1246 // whose referents are alive, and by marking from those that
a61af66fc99e Initial load
duke
parents:
diff changeset
1247 // are not active. These lists can be handled here
a61af66fc99e Initial load
duke
parents:
diff changeset
1248 // in any order and, indeed, concurrently.
a61af66fc99e Initial load
duke
parents:
diff changeset
1249 void ReferenceProcessor::preclean_discovered_references(
a61af66fc99e Initial load
duke
parents:
diff changeset
1250 BoolObjectClosure* is_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
1251 OopClosure* keep_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
1252 VoidClosure* complete_gc,
10405
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
1253 YieldClosure* yield,
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
1254 GCTimer* gc_timer) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1255
a61af66fc99e Initial load
duke
parents:
diff changeset
1256 NOT_PRODUCT(verify_ok_to_handle_reflists());
a61af66fc99e Initial load
duke
parents:
diff changeset
1257
a61af66fc99e Initial load
duke
parents:
diff changeset
1258 // Soft references
a61af66fc99e Initial load
duke
parents:
diff changeset
1259 {
10405
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
1260 GCTraceTime tt("Preclean SoftReferences", PrintGCDetails && PrintReferenceGC,
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
1261 false, gc_timer);
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
1262 for (uint i = 0; i < _max_num_q; i++) {
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1263 if (yield->should_return()) {
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1264 return;
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1265 }
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1266 preclean_discovered_reflist(_discoveredSoftRefs[i], is_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
1267 keep_alive, complete_gc, yield);
a61af66fc99e Initial load
duke
parents:
diff changeset
1268 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1269 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1270
a61af66fc99e Initial load
duke
parents:
diff changeset
1271 // Weak references
a61af66fc99e Initial load
duke
parents:
diff changeset
1272 {
10405
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
1273 GCTraceTime tt("Preclean WeakReferences", PrintGCDetails && PrintReferenceGC,
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
1274 false, gc_timer);
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
1275 for (uint i = 0; i < _max_num_q; i++) {
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1276 if (yield->should_return()) {
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1277 return;
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1278 }
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1279 preclean_discovered_reflist(_discoveredWeakRefs[i], is_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
1280 keep_alive, complete_gc, yield);
a61af66fc99e Initial load
duke
parents:
diff changeset
1281 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1282 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1283
a61af66fc99e Initial load
duke
parents:
diff changeset
1284 // Final references
a61af66fc99e Initial load
duke
parents:
diff changeset
1285 {
10405
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
1286 GCTraceTime tt("Preclean FinalReferences", PrintGCDetails && PrintReferenceGC,
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
1287 false, gc_timer);
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
1288 for (uint i = 0; i < _max_num_q; i++) {
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1289 if (yield->should_return()) {
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1290 return;
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1291 }
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1292 preclean_discovered_reflist(_discoveredFinalRefs[i], is_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
1293 keep_alive, complete_gc, yield);
a61af66fc99e Initial load
duke
parents:
diff changeset
1294 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1295 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1296
a61af66fc99e Initial load
duke
parents:
diff changeset
1297 // Phantom references
a61af66fc99e Initial load
duke
parents:
diff changeset
1298 {
10405
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
1299 GCTraceTime tt("Preclean PhantomReferences", PrintGCDetails && PrintReferenceGC,
f2110083203d 8005849: JEP 167: Event-Based JVM Tracing
sla
parents: 10327
diff changeset
1300 false, gc_timer);
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
1301 for (uint i = 0; i < _max_num_q; i++) {
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1302 if (yield->should_return()) {
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1303 return;
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1304 }
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1305 preclean_discovered_reflist(_discoveredPhantomRefs[i], is_alive,
a61af66fc99e Initial load
duke
parents:
diff changeset
1306 keep_alive, complete_gc, yield);
a61af66fc99e Initial load
duke
parents:
diff changeset
1307 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1308 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1309 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1310
a61af66fc99e Initial load
duke
parents:
diff changeset
1311 // Walk the given discovered ref list, and remove all reference objects
a61af66fc99e Initial load
duke
parents:
diff changeset
1312 // whose referents are still alive, whose referents are NULL or which
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1313 // are not active (have a non-NULL next field). NOTE: When we are
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1314 // thus precleaning the ref lists (which happens single-threaded today),
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1315 // we do not disable refs discovery to honour the correct semantics of
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1316 // java.lang.Reference. As a result, we need to be careful below
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1317 // that ref removal steps interleave safely with ref discovery steps
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1318 // (in this thread).
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1319 void
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1320 ReferenceProcessor::preclean_discovered_reflist(DiscoveredList& refs_list,
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1321 BoolObjectClosure* is_alive,
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1322 OopClosure* keep_alive,
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1323 VoidClosure* complete_gc,
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1324 YieldClosure* yield) {
17976
8e20ef014b08 8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects
brutisso
parents: 17937
diff changeset
1325 DiscoveredListIterator iter(refs_list, keep_alive, is_alive);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1326 while (iter.has_next()) {
a61af66fc99e Initial load
duke
parents:
diff changeset
1327 iter.load_ptrs(DEBUG_ONLY(true /* allow_null_referent */));
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1328 oop obj = iter.obj();
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1329 oop next = java_lang_ref_Reference::next(obj);
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1330 if (iter.referent() == NULL || iter.is_referent_alive() ||
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1331 next != NULL) {
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1332 // The referent has been cleared, or is alive, or the Reference is not
a61af66fc99e Initial load
duke
parents:
diff changeset
1333 // active; we need to trace and mark its cohort.
a61af66fc99e Initial load
duke
parents:
diff changeset
1334 if (TraceReferenceGC) {
a61af66fc99e Initial load
duke
parents:
diff changeset
1335 gclog_or_tty->print_cr("Precleaning Reference (" INTPTR_FORMAT ": %s)",
12316
190899198332 7195622: CheckUnhandledOops has limited usefulness now
hseigel
parents: 10405
diff changeset
1336 (void *)iter.obj(), iter.obj()->klass()->internal_name());
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1337 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1338 // Remove Reference object from list
a61af66fc99e Initial load
duke
parents:
diff changeset
1339 iter.remove();
a61af66fc99e Initial load
duke
parents:
diff changeset
1340 // Keep alive its cohort.
a61af66fc99e Initial load
duke
parents:
diff changeset
1341 iter.make_referent_alive();
113
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1342 if (UseCompressedOops) {
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1343 narrowOop* next_addr = (narrowOop*)java_lang_ref_Reference::next_addr(obj);
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1344 keep_alive->do_oop(next_addr);
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1345 } else {
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1346 oop* next_addr = (oop*)java_lang_ref_Reference::next_addr(obj);
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1347 keep_alive->do_oop(next_addr);
ba764ed4b6f2 6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents: 5
diff changeset
1348 }
452
00b023ae2d78 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
ysr
parents: 356
diff changeset
1349 iter.move_to_next();
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1350 } else {
a61af66fc99e Initial load
duke
parents:
diff changeset
1351 iter.next();
a61af66fc99e Initial load
duke
parents:
diff changeset
1352 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1353 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1354 // Close the reachable set
a61af66fc99e Initial load
duke
parents:
diff changeset
1355 complete_gc->do_void();
a61af66fc99e Initial load
duke
parents:
diff changeset
1356
a61af66fc99e Initial load
duke
parents:
diff changeset
1357 NOT_PRODUCT(
2369
92da084fefc9 6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads
ysr
parents: 1995
diff changeset
1358 if (PrintGCDetails && PrintReferenceGC && (iter.processed() > 0)) {
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
1359 gclog_or_tty->print_cr(" Dropped %d Refs out of %d "
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
1360 "Refs in discovered list " INTPTR_FORMAT,
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
1361 iter.removed(), iter.processed(), (address)refs_list.head());
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1362 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1363 )
a61af66fc99e Initial load
duke
parents:
diff changeset
1364 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1365
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
diff changeset
1366 const char* ReferenceProcessor::list_name(uint i) {
3979
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
1367 assert(i >= 0 && i <= _max_num_q * number_of_subclasses_of_ref(),
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
1368 "Out of bounds index");
4dfb2df418f2 6484982: G1: process references during evacuation pauses
johnc
parents: 3917
diff changeset
1369
1833
8b10f48633dc 6984287: Regularize how GC parallel workers are specified.
jmasa
parents: 1552
diff changeset
1370 int j = i / _max_num_q;
0
a61af66fc99e Initial load
duke
parents:
diff changeset
1371 switch (j) {
a61af66fc99e Initial load
duke
parents:
diff changeset
1372 case 0: return "SoftRef";
a61af66fc99e Initial load
duke
parents:
diff changeset
1373 case 1: return "WeakRef";
a61af66fc99e Initial load
duke
parents:
diff changeset
1374 case 2: return "FinalRef";
a61af66fc99e Initial load
duke
parents:
diff changeset
1375 case 3: return "PhantomRef";
a61af66fc99e Initial load
duke
parents:
diff changeset
1376 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1377 ShouldNotReachHere();
a61af66fc99e Initial load
duke
parents:
diff changeset
1378 return NULL;
a61af66fc99e Initial load
duke
parents:
diff changeset
1379 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1380
a61af66fc99e Initial load
duke
parents:
diff changeset
1381 #ifndef PRODUCT
a61af66fc99e Initial load
duke
parents:
diff changeset
1382 void ReferenceProcessor::verify_ok_to_handle_reflists() {
a61af66fc99e Initial load
duke
parents:
diff changeset
1383 // empty for now
a61af66fc99e Initial load
duke
parents:
diff changeset
1384 }
a61af66fc99e Initial load
duke
parents:
diff changeset
1385 #endif
a61af66fc99e Initial load
duke
parents:
diff changeset
1386
a61af66fc99e Initial load
duke
parents:
diff changeset
1387 #ifndef PRODUCT
a61af66fc99e Initial load
duke
parents:
diff changeset
1388 void ReferenceProcessor::clear_discovered_references() {
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duke
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1389 guarantee(!_discovering_refs, "Discovering refs?");
4728
441e946dc1af 7121618: Change type of number of GC workers to unsigned int.
jmasa
parents: 4712
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1390 for (uint i = 0; i < _max_num_q * number_of_subclasses_of_ref(); i++) {
4014
bf2d2b8b1726 7095243: Disambiguate ReferenceProcessor::_discoveredSoftRefs
johnc
parents: 3992
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1391 clear_discovered_references(_discovered_refs[i]);
0
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duke
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1392 }
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duke
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1393 }
3915
c2bf0120ee5d 7085906: Replace the permgen allocated sentinelRef with a self-looped end
stefank
parents: 2369
diff changeset
1394
0
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duke
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1395 #endif // PRODUCT