0
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1 /*
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2 * Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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4 *
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5 * This code is free software; you can redistribute it and/or modify it
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6 * under the terms of the GNU General Public License version 2 only, as
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7 * published by the Free Software Foundation.
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8 *
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9 * This code is distributed in the hope that it will be useful, but WITHOUT
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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12 * version 2 for more details (a copy is included in the LICENSE file that
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13 * accompanied this code).
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14 *
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15 * You should have received a copy of the GNU General Public License version
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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18 *
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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20 * CA 95054 USA or visit www.sun.com if you need additional information or
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21 * have any questions.
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22 *
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23 */
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24
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25 #include "incls/_precompiled.incl"
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26 #include "incls/_psMarkSweep.cpp.incl"
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27
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28 elapsedTimer PSMarkSweep::_accumulated_time;
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29 unsigned int PSMarkSweep::_total_invocations = 0;
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30 jlong PSMarkSweep::_time_of_last_gc = 0;
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31 CollectorCounters* PSMarkSweep::_counters = NULL;
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32
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33 void PSMarkSweep::initialize() {
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34 MemRegion mr = Universe::heap()->reserved_region();
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35 _ref_processor = new ReferenceProcessor(mr,
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36 true, // atomic_discovery
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37 false); // mt_discovery
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38 if (!UseParallelOldGC || !VerifyParallelOldWithMarkSweep) {
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39 _counters = new CollectorCounters("PSMarkSweep", 1);
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40 }
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41 }
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42
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43 // This method contains all heap specific policy for invoking mark sweep.
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44 // PSMarkSweep::invoke_no_policy() will only attempt to mark-sweep-compact
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45 // the heap. It will do nothing further. If we need to bail out for policy
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46 // reasons, scavenge before full gc, or any other specialized behavior, it
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47 // needs to be added here.
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48 //
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49 // Note that this method should only be called from the vm_thread while
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50 // at a safepoint!
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51 void PSMarkSweep::invoke(bool maximum_heap_compaction) {
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52 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
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53 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
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54 assert(!Universe::heap()->is_gc_active(), "not reentrant");
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55
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56 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
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57 GCCause::Cause gc_cause = heap->gc_cause();
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58 PSAdaptiveSizePolicy* policy = heap->size_policy();
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59
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60 // Before each allocation/collection attempt, find out from the
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61 // policy object if GCs are, on the whole, taking too long. If so,
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62 // bail out without attempting a collection. The exceptions are
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63 // for explicitly requested GC's.
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64 if (!policy->gc_time_limit_exceeded() ||
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65 GCCause::is_user_requested_gc(gc_cause) ||
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66 GCCause::is_serviceability_requested_gc(gc_cause)) {
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67 IsGCActiveMark mark;
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68
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69 if (ScavengeBeforeFullGC) {
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70 PSScavenge::invoke_no_policy();
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71 }
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72
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73 int count = (maximum_heap_compaction)?1:MarkSweepAlwaysCompactCount;
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74 IntFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count);
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75 PSMarkSweep::invoke_no_policy(maximum_heap_compaction);
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76 }
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77 }
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78
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79 // This method contains no policy. You should probably
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80 // be calling invoke() instead.
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81 void PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) {
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82 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
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83 assert(ref_processor() != NULL, "Sanity");
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84
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85 if (GC_locker::check_active_before_gc()) {
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86 return;
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87 }
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88
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89 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
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90 GCCause::Cause gc_cause = heap->gc_cause();
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91 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
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92 PSAdaptiveSizePolicy* size_policy = heap->size_policy();
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93
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94 PSYoungGen* young_gen = heap->young_gen();
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95 PSOldGen* old_gen = heap->old_gen();
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96 PSPermGen* perm_gen = heap->perm_gen();
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97
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98 // Increment the invocation count
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99 heap->increment_total_collections(true /* full */);
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100
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101 // We need to track unique mark sweep invocations as well.
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102 _total_invocations++;
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103
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104 AdaptiveSizePolicyOutput(size_policy, heap->total_collections());
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105
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106 if (PrintHeapAtGC) {
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107 Universe::print_heap_before_gc();
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108 }
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109
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110 // Fill in TLABs
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111 heap->accumulate_statistics_all_tlabs();
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112 heap->ensure_parsability(true); // retire TLABs
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113
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114 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
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115 HandleMark hm; // Discard invalid handles created during verification
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116 gclog_or_tty->print(" VerifyBeforeGC:");
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117 Universe::verify(true);
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118 }
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119
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120 // Verify object start arrays
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121 if (VerifyObjectStartArray &&
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122 VerifyBeforeGC) {
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123 old_gen->verify_object_start_array();
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124 perm_gen->verify_object_start_array();
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125 }
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126
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127 // Filled in below to track the state of the young gen after the collection.
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128 bool eden_empty;
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129 bool survivors_empty;
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130 bool young_gen_empty;
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131
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132 {
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133 HandleMark hm;
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134 const bool is_system_gc = gc_cause == GCCause::_java_lang_system_gc;
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135 // This is useful for debugging but don't change the output the
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136 // the customer sees.
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137 const char* gc_cause_str = "Full GC";
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138 if (is_system_gc && PrintGCDetails) {
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139 gc_cause_str = "Full GC (System)";
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140 }
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141 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
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142 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
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143 TraceTime t1(gc_cause_str, PrintGC, !PrintGCDetails, gclog_or_tty);
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144 TraceCollectorStats tcs(counters());
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145 TraceMemoryManagerStats tms(true /* Full GC */);
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146
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147 if (TraceGen1Time) accumulated_time()->start();
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148
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149 // Let the size policy know we're starting
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150 size_policy->major_collection_begin();
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151
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152 // When collecting the permanent generation methodOops may be moving,
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153 // so we either have to flush all bcp data or convert it into bci.
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154 CodeCache::gc_prologue();
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155 Threads::gc_prologue();
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156 BiasedLocking::preserve_marks();
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157
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158 // Capture heap size before collection for printing.
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159 size_t prev_used = heap->used();
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160
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161 // Capture perm gen size before collection for sizing.
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162 size_t perm_gen_prev_used = perm_gen->used_in_bytes();
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163
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164 // For PrintGCDetails
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165 size_t old_gen_prev_used = old_gen->used_in_bytes();
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166 size_t young_gen_prev_used = young_gen->used_in_bytes();
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167
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168 allocate_stacks();
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169
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170 NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
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171 COMPILER2_PRESENT(DerivedPointerTable::clear());
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172
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173 ref_processor()->enable_discovery();
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174
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175 mark_sweep_phase1(clear_all_softrefs);
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176
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177 mark_sweep_phase2();
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178
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179 // Don't add any more derived pointers during phase3
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180 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
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181 COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
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182
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183 mark_sweep_phase3();
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184
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185 mark_sweep_phase4();
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186
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187 restore_marks();
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188
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189 deallocate_stacks();
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190
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191 eden_empty = young_gen->eden_space()->is_empty();
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192 if (!eden_empty) {
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193 eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen);
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194 }
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195
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196 // Update heap occupancy information which is used as
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197 // input to soft ref clearing policy at the next gc.
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198 Universe::update_heap_info_at_gc();
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199
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200 survivors_empty = young_gen->from_space()->is_empty() &&
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201 young_gen->to_space()->is_empty();
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202 young_gen_empty = eden_empty && survivors_empty;
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203
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204 BarrierSet* bs = heap->barrier_set();
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205 if (bs->is_a(BarrierSet::ModRef)) {
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206 ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs;
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207 MemRegion old_mr = heap->old_gen()->reserved();
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208 MemRegion perm_mr = heap->perm_gen()->reserved();
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209 assert(perm_mr.end() <= old_mr.start(), "Generations out of order");
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210
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211 if (young_gen_empty) {
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212 modBS->clear(MemRegion(perm_mr.start(), old_mr.end()));
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213 } else {
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214 modBS->invalidate(MemRegion(perm_mr.start(), old_mr.end()));
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215 }
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216 }
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217
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218 BiasedLocking::restore_marks();
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219 Threads::gc_epilogue();
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220 CodeCache::gc_epilogue();
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221
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222 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
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223
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224 ref_processor()->enqueue_discovered_references(NULL);
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225
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226 // Update time of last GC
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227 reset_millis_since_last_gc();
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228
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229 // Let the size policy know we're done
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230 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause);
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231
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232 if (UseAdaptiveSizePolicy) {
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233
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234 if (PrintAdaptiveSizePolicy) {
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235 gclog_or_tty->print("AdaptiveSizeStart: ");
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236 gclog_or_tty->stamp();
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237 gclog_or_tty->print_cr(" collection: %d ",
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238 heap->total_collections());
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239 if (Verbose) {
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240 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d"
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241 " perm_gen_capacity: %d ",
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242 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(),
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243 perm_gen->capacity_in_bytes());
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244 }
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245 }
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246
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247 // Don't check if the size_policy is ready here. Let
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248 // the size_policy check that internally.
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249 if (UseAdaptiveGenerationSizePolicyAtMajorCollection &&
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250 ((gc_cause != GCCause::_java_lang_system_gc) ||
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251 UseAdaptiveSizePolicyWithSystemGC)) {
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252 // Calculate optimal free space amounts
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253 assert(young_gen->max_size() >
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254 young_gen->from_space()->capacity_in_bytes() +
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255 young_gen->to_space()->capacity_in_bytes(),
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256 "Sizes of space in young gen are out-of-bounds");
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257 size_t max_eden_size = young_gen->max_size() -
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258 young_gen->from_space()->capacity_in_bytes() -
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259 young_gen->to_space()->capacity_in_bytes();
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260 size_policy->compute_generation_free_space(young_gen->used_in_bytes(),
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261 young_gen->eden_space()->used_in_bytes(),
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262 old_gen->used_in_bytes(),
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263 perm_gen->used_in_bytes(),
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264 young_gen->eden_space()->capacity_in_bytes(),
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265 old_gen->max_gen_size(),
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266 max_eden_size,
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267 true /* full gc*/,
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268 gc_cause);
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269
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270 heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes());
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271
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272 // Don't resize the young generation at an major collection. A
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273 // desired young generation size may have been calculated but
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274 // resizing the young generation complicates the code because the
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275 // resizing of the old generation may have moved the boundary
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276 // between the young generation and the old generation. Let the
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277 // young generation resizing happen at the minor collections.
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278 }
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279 if (PrintAdaptiveSizePolicy) {
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280 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ",
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281 heap->total_collections());
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282 }
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283 }
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284
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285 if (UsePerfData) {
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286 heap->gc_policy_counters()->update_counters();
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287 heap->gc_policy_counters()->update_old_capacity(
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288 old_gen->capacity_in_bytes());
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289 heap->gc_policy_counters()->update_young_capacity(
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290 young_gen->capacity_in_bytes());
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291 }
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292
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293 heap->resize_all_tlabs();
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294
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295 // We collected the perm gen, so we'll resize it here.
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296 perm_gen->compute_new_size(perm_gen_prev_used);
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297
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298 if (TraceGen1Time) accumulated_time()->stop();
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299
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300 if (PrintGC) {
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301 if (PrintGCDetails) {
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302 // Don't print a GC timestamp here. This is after the GC so
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303 // would be confusing.
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304 young_gen->print_used_change(young_gen_prev_used);
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305 old_gen->print_used_change(old_gen_prev_used);
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306 }
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307 heap->print_heap_change(prev_used);
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308 // Do perm gen after heap becase prev_used does
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309 // not include the perm gen (done this way in the other
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310 // collectors).
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311 if (PrintGCDetails) {
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312 perm_gen->print_used_change(perm_gen_prev_used);
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313 }
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314 }
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315
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316 // Track memory usage and detect low memory
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317 MemoryService::track_memory_usage();
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318 heap->update_counters();
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319
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320 if (PrintGCDetails) {
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321 if (size_policy->print_gc_time_limit_would_be_exceeded()) {
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322 if (size_policy->gc_time_limit_exceeded()) {
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323 gclog_or_tty->print_cr(" GC time is exceeding GCTimeLimit "
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324 "of %d%%", GCTimeLimit);
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325 } else {
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326 gclog_or_tty->print_cr(" GC time would exceed GCTimeLimit "
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327 "of %d%%", GCTimeLimit);
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328 }
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329 }
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330 size_policy->set_print_gc_time_limit_would_be_exceeded(false);
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331 }
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332 }
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333
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334 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
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335 HandleMark hm; // Discard invalid handles created during verification
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336 gclog_or_tty->print(" VerifyAfterGC:");
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337 Universe::verify(false);
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338 }
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339
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340 // Re-verify object start arrays
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341 if (VerifyObjectStartArray &&
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342 VerifyAfterGC) {
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343 old_gen->verify_object_start_array();
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344 perm_gen->verify_object_start_array();
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345 }
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346
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347 NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
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348
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349 if (PrintHeapAtGC) {
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350 Universe::print_heap_after_gc();
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351 }
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352 }
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353
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354 bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
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355 PSYoungGen* young_gen,
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356 PSOldGen* old_gen) {
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357 MutableSpace* const eden_space = young_gen->eden_space();
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358 assert(!eden_space->is_empty(), "eden must be non-empty");
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359 assert(young_gen->virtual_space()->alignment() ==
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360 old_gen->virtual_space()->alignment(), "alignments do not match");
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361
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362 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) {
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363 return false;
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364 }
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365
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366 // Both generations must be completely committed.
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367 if (young_gen->virtual_space()->uncommitted_size() != 0) {
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368 return false;
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369 }
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370 if (old_gen->virtual_space()->uncommitted_size() != 0) {
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371 return false;
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372 }
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373
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374 // Figure out how much to take from eden. Include the average amount promoted
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375 // in the total; otherwise the next young gen GC will simply bail out to a
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376 // full GC.
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377 const size_t alignment = old_gen->virtual_space()->alignment();
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378 const size_t eden_used = eden_space->used_in_bytes();
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379 const size_t promoted = (size_t)(size_policy->avg_promoted()->padded_average());
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380 const size_t absorb_size = align_size_up(eden_used + promoted, alignment);
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381 const size_t eden_capacity = eden_space->capacity_in_bytes();
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382
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383 if (absorb_size >= eden_capacity) {
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384 return false; // Must leave some space in eden.
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385 }
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386
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387 const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size;
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388 if (new_young_size < young_gen->min_gen_size()) {
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389 return false; // Respect young gen minimum size.
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390 }
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391
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392 if (TraceAdaptiveGCBoundary && Verbose) {
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393 gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: "
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394 "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K "
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395 "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K "
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396 "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ",
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397 absorb_size / K,
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398 eden_capacity / K, (eden_capacity - absorb_size) / K,
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399 young_gen->from_space()->used_in_bytes() / K,
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400 young_gen->to_space()->used_in_bytes() / K,
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401 young_gen->capacity_in_bytes() / K, new_young_size / K);
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402 }
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403
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404 // Fill the unused part of the old gen.
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405 MutableSpace* const old_space = old_gen->object_space();
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406 MemRegion old_gen_unused(old_space->top(), old_space->end());
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407
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408 // If the unused part of the old gen cannot be filled, skip
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409 // absorbing eden.
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410 if (old_gen_unused.word_size() < SharedHeap::min_fill_size()) {
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411 return false;
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412 }
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413
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414 if (!old_gen_unused.is_empty()) {
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415 SharedHeap::fill_region_with_object(old_gen_unused);
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416 }
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417
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418 // Take the live data from eden and set both top and end in the old gen to
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419 // eden top. (Need to set end because reset_after_change() mangles the region
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420 // from end to virtual_space->high() in debug builds).
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421 HeapWord* const new_top = eden_space->top();
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422 old_gen->virtual_space()->expand_into(young_gen->virtual_space(),
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423 absorb_size);
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424 young_gen->reset_after_change();
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425 old_space->set_top(new_top);
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426 old_space->set_end(new_top);
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427 old_gen->reset_after_change();
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428
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429 // Update the object start array for the filler object and the data from eden.
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430 ObjectStartArray* const start_array = old_gen->start_array();
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431 HeapWord* const start = old_gen_unused.start();
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432 for (HeapWord* addr = start; addr < new_top; addr += oop(addr)->size()) {
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433 start_array->allocate_block(addr);
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434 }
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435
|
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436 // Could update the promoted average here, but it is not typically updated at
|
|
437 // full GCs and the value to use is unclear. Something like
|
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438 //
|
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439 // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc.
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440
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441 size_policy->set_bytes_absorbed_from_eden(absorb_size);
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442 return true;
|
|
443 }
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444
|
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445 void PSMarkSweep::allocate_stacks() {
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446 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
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447 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
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448
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449 PSYoungGen* young_gen = heap->young_gen();
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450
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451 MutableSpace* to_space = young_gen->to_space();
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452 _preserved_marks = (PreservedMark*)to_space->top();
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453 _preserved_count = 0;
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454
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455 // We want to calculate the size in bytes first.
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456 _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte));
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457 // Now divide by the size of a PreservedMark
|
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458 _preserved_count_max /= sizeof(PreservedMark);
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459
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460 _preserved_mark_stack = NULL;
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461 _preserved_oop_stack = NULL;
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462
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463 _marking_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true);
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464
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465 int size = SystemDictionary::number_of_classes() * 2;
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466 _revisit_klass_stack = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true);
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467 }
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468
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469
|
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470 void PSMarkSweep::deallocate_stacks() {
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471 if (_preserved_oop_stack) {
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472 delete _preserved_mark_stack;
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473 _preserved_mark_stack = NULL;
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474 delete _preserved_oop_stack;
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475 _preserved_oop_stack = NULL;
|
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476 }
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477
|
|
478 delete _marking_stack;
|
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479 delete _revisit_klass_stack;
|
|
480 }
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|
481
|
|
482 void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) {
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483 // Recursively traverse all live objects and mark them
|
|
484 EventMark m("1 mark object");
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485 TraceTime tm("phase 1", PrintGCDetails && Verbose, true, gclog_or_tty);
|
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486 trace(" 1");
|
|
487
|
|
488 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
|
|
489 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
|
|
490
|
|
491 // General strong roots.
|
|
492 Universe::oops_do(mark_and_push_closure());
|
|
493 ReferenceProcessor::oops_do(mark_and_push_closure());
|
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494 JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles
|
|
495 Threads::oops_do(mark_and_push_closure());
|
|
496 ObjectSynchronizer::oops_do(mark_and_push_closure());
|
|
497 FlatProfiler::oops_do(mark_and_push_closure());
|
|
498 Management::oops_do(mark_and_push_closure());
|
|
499 JvmtiExport::oops_do(mark_and_push_closure());
|
|
500 SystemDictionary::always_strong_oops_do(mark_and_push_closure());
|
|
501 vmSymbols::oops_do(mark_and_push_closure());
|
|
502
|
|
503 // Flush marking stack.
|
|
504 follow_stack();
|
|
505
|
|
506 // Process reference objects found during marking
|
|
507
|
|
508 // Skipping the reference processing for VerifyParallelOldWithMarkSweep
|
|
509 // affects the marking (makes it different).
|
|
510 {
|
|
511 ReferencePolicy *soft_ref_policy;
|
|
512 if (clear_all_softrefs) {
|
|
513 soft_ref_policy = new AlwaysClearPolicy();
|
|
514 } else {
|
|
515 #ifdef COMPILER2
|
|
516 soft_ref_policy = new LRUMaxHeapPolicy();
|
|
517 #else
|
|
518 soft_ref_policy = new LRUCurrentHeapPolicy();
|
|
519 #endif // COMPILER2
|
|
520 }
|
|
521 assert(soft_ref_policy != NULL,"No soft reference policy");
|
|
522 ref_processor()->process_discovered_references(
|
|
523 soft_ref_policy, is_alive_closure(), mark_and_push_closure(),
|
|
524 follow_stack_closure(), NULL);
|
|
525 }
|
|
526
|
|
527 // Follow system dictionary roots and unload classes
|
|
528 bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
|
|
529
|
|
530 // Follow code cache roots
|
|
531 CodeCache::do_unloading(is_alive_closure(), mark_and_push_closure(),
|
|
532 purged_class);
|
|
533 follow_stack(); // Flush marking stack
|
|
534
|
|
535 // Update subklass/sibling/implementor links of live klasses
|
|
536 follow_weak_klass_links();
|
|
537 assert(_marking_stack->is_empty(), "just drained");
|
|
538
|
|
539 // Visit symbol and interned string tables and delete unmarked oops
|
|
540 SymbolTable::unlink(is_alive_closure());
|
|
541 StringTable::unlink(is_alive_closure());
|
|
542
|
|
543 assert(_marking_stack->is_empty(), "stack should be empty by now");
|
|
544 }
|
|
545
|
|
546
|
|
547 void PSMarkSweep::mark_sweep_phase2() {
|
|
548 EventMark m("2 compute new addresses");
|
|
549 TraceTime tm("phase 2", PrintGCDetails && Verbose, true, gclog_or_tty);
|
|
550 trace("2");
|
|
551
|
|
552 // Now all live objects are marked, compute the new object addresses.
|
|
553
|
|
554 // It is imperative that we traverse perm_gen LAST. If dead space is
|
|
555 // allowed a range of dead object may get overwritten by a dead int
|
|
556 // array. If perm_gen is not traversed last a klassOop may get
|
|
557 // overwritten. This is fine since it is dead, but if the class has dead
|
|
558 // instances we have to skip them, and in order to find their size we
|
|
559 // need the klassOop!
|
|
560 //
|
|
561 // It is not required that we traverse spaces in the same order in
|
|
562 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops
|
|
563 // tracking expects us to do so. See comment under phase4.
|
|
564
|
|
565 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
|
|
566 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
|
|
567
|
|
568 PSOldGen* old_gen = heap->old_gen();
|
|
569 PSPermGen* perm_gen = heap->perm_gen();
|
|
570
|
|
571 // Begin compacting into the old gen
|
|
572 PSMarkSweepDecorator::set_destination_decorator_tenured();
|
|
573
|
|
574 // This will also compact the young gen spaces.
|
|
575 old_gen->precompact();
|
|
576
|
|
577 // Compact the perm gen into the perm gen
|
|
578 PSMarkSweepDecorator::set_destination_decorator_perm_gen();
|
|
579
|
|
580 perm_gen->precompact();
|
|
581 }
|
|
582
|
|
583 // This should be moved to the shared markSweep code!
|
|
584 class PSAlwaysTrueClosure: public BoolObjectClosure {
|
|
585 public:
|
|
586 void do_object(oop p) { ShouldNotReachHere(); }
|
|
587 bool do_object_b(oop p) { return true; }
|
|
588 };
|
|
589 static PSAlwaysTrueClosure always_true;
|
|
590
|
|
591 void PSMarkSweep::mark_sweep_phase3() {
|
|
592 // Adjust the pointers to reflect the new locations
|
|
593 EventMark m("3 adjust pointers");
|
|
594 TraceTime tm("phase 3", PrintGCDetails && Verbose, true, gclog_or_tty);
|
|
595 trace("3");
|
|
596
|
|
597 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
|
|
598 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
|
|
599
|
|
600 PSYoungGen* young_gen = heap->young_gen();
|
|
601 PSOldGen* old_gen = heap->old_gen();
|
|
602 PSPermGen* perm_gen = heap->perm_gen();
|
|
603
|
|
604 // General strong roots.
|
|
605 Universe::oops_do(adjust_root_pointer_closure());
|
|
606 ReferenceProcessor::oops_do(adjust_root_pointer_closure());
|
|
607 JNIHandles::oops_do(adjust_root_pointer_closure()); // Global (strong) JNI handles
|
|
608 Threads::oops_do(adjust_root_pointer_closure());
|
|
609 ObjectSynchronizer::oops_do(adjust_root_pointer_closure());
|
|
610 FlatProfiler::oops_do(adjust_root_pointer_closure());
|
|
611 Management::oops_do(adjust_root_pointer_closure());
|
|
612 JvmtiExport::oops_do(adjust_root_pointer_closure());
|
|
613 // SO_AllClasses
|
|
614 SystemDictionary::oops_do(adjust_root_pointer_closure());
|
|
615 vmSymbols::oops_do(adjust_root_pointer_closure());
|
|
616
|
|
617 // Now adjust pointers in remaining weak roots. (All of which should
|
|
618 // have been cleared if they pointed to non-surviving objects.)
|
|
619 // Global (weak) JNI handles
|
|
620 JNIHandles::weak_oops_do(&always_true, adjust_root_pointer_closure());
|
|
621
|
|
622 CodeCache::oops_do(adjust_pointer_closure());
|
|
623 SymbolTable::oops_do(adjust_root_pointer_closure());
|
|
624 StringTable::oops_do(adjust_root_pointer_closure());
|
|
625 ref_processor()->weak_oops_do(adjust_root_pointer_closure());
|
|
626 PSScavenge::reference_processor()->weak_oops_do(adjust_root_pointer_closure());
|
|
627
|
|
628 adjust_marks();
|
|
629
|
|
630 young_gen->adjust_pointers();
|
|
631 old_gen->adjust_pointers();
|
|
632 perm_gen->adjust_pointers();
|
|
633 }
|
|
634
|
|
635 void PSMarkSweep::mark_sweep_phase4() {
|
|
636 EventMark m("4 compact heap");
|
|
637 TraceTime tm("phase 4", PrintGCDetails && Verbose, true, gclog_or_tty);
|
|
638 trace("4");
|
|
639
|
|
640 // All pointers are now adjusted, move objects accordingly
|
|
641
|
|
642 // It is imperative that we traverse perm_gen first in phase4. All
|
|
643 // classes must be allocated earlier than their instances, and traversing
|
|
644 // perm_gen first makes sure that all klassOops have moved to their new
|
|
645 // location before any instance does a dispatch through it's klass!
|
|
646 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
|
|
647 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
|
|
648
|
|
649 PSYoungGen* young_gen = heap->young_gen();
|
|
650 PSOldGen* old_gen = heap->old_gen();
|
|
651 PSPermGen* perm_gen = heap->perm_gen();
|
|
652
|
|
653 perm_gen->compact();
|
|
654 old_gen->compact();
|
|
655 young_gen->compact();
|
|
656 }
|
|
657
|
|
658 jlong PSMarkSweep::millis_since_last_gc() {
|
|
659 jlong ret_val = os::javaTimeMillis() - _time_of_last_gc;
|
|
660 // XXX See note in genCollectedHeap::millis_since_last_gc().
|
|
661 if (ret_val < 0) {
|
|
662 NOT_PRODUCT(warning("time warp: %d", ret_val);)
|
|
663 return 0;
|
|
664 }
|
|
665 return ret_val;
|
|
666 }
|
|
667
|
|
668 void PSMarkSweep::reset_millis_since_last_gc() {
|
|
669 _time_of_last_gc = os::javaTimeMillis();
|
|
670 }
|