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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 // ConcurrentMarkSweepGeneration is in support of a concurrent
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26 // mark-sweep old generation in the Detlefs-Printezis--Boehm-Demers-Schenker
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27 // style. We assume, for now, that this generation is always the
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28 // seniormost generation (modulo the PermGeneration), and for simplicity
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29 // in the first implementation, that this generation is a single compactible
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30 // space. Neither of these restrictions appears essential, and will be
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31 // relaxed in the future when more time is available to implement the
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32 // greater generality (and there's a need for it).
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33 //
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34 // Concurrent mode failures are currently handled by
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35 // means of a sliding mark-compact.
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36
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37 class CMSAdaptiveSizePolicy;
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38 class CMSConcMarkingTask;
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39 class CMSGCAdaptivePolicyCounters;
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40 class ConcurrentMarkSweepGeneration;
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41 class ConcurrentMarkSweepPolicy;
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42 class ConcurrentMarkSweepThread;
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43 class CompactibleFreeListSpace;
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44 class FreeChunk;
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45 class PromotionInfo;
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46 class ScanMarkedObjectsAgainCarefullyClosure;
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47
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48 // A generic CMS bit map. It's the basis for both the CMS marking bit map
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49 // as well as for the mod union table (in each case only a subset of the
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50 // methods are used). This is essentially a wrapper around the BitMap class,
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51 // with one bit per (1<<_shifter) HeapWords. (i.e. for the marking bit map,
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52 // we have _shifter == 0. and for the mod union table we have
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53 // shifter == CardTableModRefBS::card_shift - LogHeapWordSize.)
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54 // XXX 64-bit issues in BitMap?
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55 class CMSBitMap VALUE_OBJ_CLASS_SPEC {
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56 friend class VMStructs;
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57
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58 HeapWord* _bmStartWord; // base address of range covered by map
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59 size_t _bmWordSize; // map size (in #HeapWords covered)
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60 const int _shifter; // shifts to convert HeapWord to bit position
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61 VirtualSpace _virtual_space; // underlying the bit map
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62 BitMap _bm; // the bit map itself
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63 public:
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64 Mutex* const _lock; // mutex protecting _bm;
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65
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66 public:
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67 // constructor
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68 CMSBitMap(int shifter, int mutex_rank, const char* mutex_name);
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69
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70 // allocates the actual storage for the map
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71 bool allocate(MemRegion mr);
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72 // field getter
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73 Mutex* lock() const { return _lock; }
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74 // locking verifier convenience function
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75 void assert_locked() const PRODUCT_RETURN;
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76
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77 // inquiries
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78 HeapWord* startWord() const { return _bmStartWord; }
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79 size_t sizeInWords() const { return _bmWordSize; }
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80 size_t sizeInBits() const { return _bm.size(); }
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81 // the following is one past the last word in space
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82 HeapWord* endWord() const { return _bmStartWord + _bmWordSize; }
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83
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84 // reading marks
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85 bool isMarked(HeapWord* addr) const;
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86 bool par_isMarked(HeapWord* addr) const; // do not lock checks
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87 bool isUnmarked(HeapWord* addr) const;
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88 bool isAllClear() const;
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89
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90 // writing marks
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91 void mark(HeapWord* addr);
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92 // For marking by parallel GC threads;
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93 // returns true if we did, false if another thread did
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94 bool par_mark(HeapWord* addr);
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95
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96 void mark_range(MemRegion mr);
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97 void par_mark_range(MemRegion mr);
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98 void mark_large_range(MemRegion mr);
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99 void par_mark_large_range(MemRegion mr);
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100 void par_clear(HeapWord* addr); // For unmarking by parallel GC threads.
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101 void clear_range(MemRegion mr);
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102 void par_clear_range(MemRegion mr);
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103 void clear_large_range(MemRegion mr);
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104 void par_clear_large_range(MemRegion mr);
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105 void clear_all();
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106 void clear_all_incrementally(); // Not yet implemented!!
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107
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108 NOT_PRODUCT(
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109 // checks the memory region for validity
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110 void region_invariant(MemRegion mr);
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111 )
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112
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113 // iteration
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114 void iterate(BitMapClosure* cl) {
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115 _bm.iterate(cl);
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116 }
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117 void iterate(BitMapClosure* cl, HeapWord* left, HeapWord* right);
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118 void dirty_range_iterate_clear(MemRegionClosure* cl);
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119 void dirty_range_iterate_clear(MemRegion mr, MemRegionClosure* cl);
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120
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121 // auxiliary support for iteration
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122 HeapWord* getNextMarkedWordAddress(HeapWord* addr) const;
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123 HeapWord* getNextMarkedWordAddress(HeapWord* start_addr,
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124 HeapWord* end_addr) const;
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125 HeapWord* getNextUnmarkedWordAddress(HeapWord* addr) const;
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126 HeapWord* getNextUnmarkedWordAddress(HeapWord* start_addr,
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127 HeapWord* end_addr) const;
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128 MemRegion getAndClearMarkedRegion(HeapWord* addr);
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129 MemRegion getAndClearMarkedRegion(HeapWord* start_addr,
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130 HeapWord* end_addr);
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131
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132 // conversion utilities
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133 HeapWord* offsetToHeapWord(size_t offset) const;
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134 size_t heapWordToOffset(HeapWord* addr) const;
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135 size_t heapWordDiffToOffsetDiff(size_t diff) const;
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136
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137 // debugging
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138 // is this address range covered by the bit-map?
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139 NOT_PRODUCT(
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140 bool covers(MemRegion mr) const;
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141 bool covers(HeapWord* start, size_t size = 0) const;
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142 )
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143 void verifyNoOneBitsInRange(HeapWord* left, HeapWord* right) PRODUCT_RETURN;
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144 };
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145
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146 // Represents a marking stack used by the CMS collector.
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147 // Ideally this should be GrowableArray<> just like MSC's marking stack(s).
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148 class CMSMarkStack: public CHeapObj {
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149 //
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150 friend class CMSCollector; // to get at expasion stats further below
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151 //
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152
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153 VirtualSpace _virtual_space; // space for the stack
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154 oop* _base; // bottom of stack
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155 size_t _index; // one more than last occupied index
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156 size_t _capacity; // max #elements
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157 Mutex _par_lock; // an advisory lock used in case of parallel access
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158 NOT_PRODUCT(size_t _max_depth;) // max depth plumbed during run
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159
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160 protected:
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161 size_t _hit_limit; // we hit max stack size limit
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162 size_t _failed_double; // we failed expansion before hitting limit
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163
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164 public:
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165 CMSMarkStack():
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166 _par_lock(Mutex::event, "CMSMarkStack._par_lock", true),
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167 _hit_limit(0),
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168 _failed_double(0) {}
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169
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170 bool allocate(size_t size);
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171
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172 size_t capacity() const { return _capacity; }
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173
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174 oop pop() {
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175 if (!isEmpty()) {
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176 return _base[--_index] ;
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177 }
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178 return NULL;
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179 }
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180
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181 bool push(oop ptr) {
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182 if (isFull()) {
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183 return false;
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184 } else {
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185 _base[_index++] = ptr;
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186 NOT_PRODUCT(_max_depth = MAX2(_max_depth, _index));
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187 return true;
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188 }
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189 }
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190
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191 bool isEmpty() const { return _index == 0; }
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192 bool isFull() const {
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193 assert(_index <= _capacity, "buffer overflow");
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194 return _index == _capacity;
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195 }
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196
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197 size_t length() { return _index; }
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198
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199 // "Parallel versions" of some of the above
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200 oop par_pop() {
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201 // lock and pop
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202 MutexLockerEx x(&_par_lock, Mutex::_no_safepoint_check_flag);
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203 return pop();
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204 }
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205
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206 bool par_push(oop ptr) {
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207 // lock and push
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208 MutexLockerEx x(&_par_lock, Mutex::_no_safepoint_check_flag);
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209 return push(ptr);
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210 }
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211
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212 // Forcibly reset the stack, losing all of its contents.
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213 void reset() {
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214 _index = 0;
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215 }
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216
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217 // Expand the stack, typically in response to an overflow condition
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218 void expand();
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219
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220 // Compute the least valued stack element.
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221 oop least_value(HeapWord* low) {
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222 oop least = (oop)low;
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223 for (size_t i = 0; i < _index; i++) {
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224 least = MIN2(least, _base[i]);
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225 }
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226 return least;
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227 }
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228
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229 // Exposed here to allow stack expansion in || case
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230 Mutex* par_lock() { return &_par_lock; }
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231 };
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232
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233 class CardTableRS;
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234 class CMSParGCThreadState;
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235
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236 class ModUnionClosure: public MemRegionClosure {
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237 protected:
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238 CMSBitMap* _t;
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239 public:
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240 ModUnionClosure(CMSBitMap* t): _t(t) { }
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241 void do_MemRegion(MemRegion mr);
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242 };
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243
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244 class ModUnionClosurePar: public ModUnionClosure {
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245 public:
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246 ModUnionClosurePar(CMSBitMap* t): ModUnionClosure(t) { }
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247 void do_MemRegion(MemRegion mr);
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248 };
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249
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250 // Survivor Chunk Array in support of parallelization of
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251 // Survivor Space rescan.
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252 class ChunkArray: public CHeapObj {
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253 size_t _index;
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254 size_t _capacity;
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255 HeapWord** _array; // storage for array
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256
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257 public:
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258 ChunkArray() : _index(0), _capacity(0), _array(NULL) {}
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259 ChunkArray(HeapWord** a, size_t c):
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260 _index(0), _capacity(c), _array(a) {}
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261
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262 HeapWord** array() { return _array; }
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263 void set_array(HeapWord** a) { _array = a; }
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264
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265 size_t capacity() { return _capacity; }
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266 void set_capacity(size_t c) { _capacity = c; }
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267
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268 size_t end() {
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269 assert(_index < capacity(), "_index out of bounds");
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270 return _index;
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271 } // exclusive
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272
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273 HeapWord* nth(size_t n) {
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274 assert(n < end(), "Out of bounds access");
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275 return _array[n];
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276 }
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277
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278 void reset() {
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279 _index = 0;
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280 }
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281
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282 void record_sample(HeapWord* p, size_t sz) {
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283 // For now we do not do anything with the size
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284 if (_index < _capacity) {
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285 _array[_index++] = p;
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286 }
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287 }
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288 };
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289
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290 //
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291 // Timing, allocation and promotion statistics for gc scheduling and incremental
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292 // mode pacing. Most statistics are exponential averages.
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293 //
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294 class CMSStats VALUE_OBJ_CLASS_SPEC {
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295 private:
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296 ConcurrentMarkSweepGeneration* const _cms_gen; // The cms (old) gen.
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297
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298 // The following are exponential averages with factor alpha:
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299 // avg = (100 - alpha) * avg + alpha * cur_sample
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300 //
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301 // The durations measure: end_time[n] - start_time[n]
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302 // The periods measure: start_time[n] - start_time[n-1]
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303 //
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304 // The cms period and duration include only concurrent collections; time spent
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305 // in foreground cms collections due to System.gc() or because of a failure to
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306 // keep up are not included.
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307 //
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308 // There are 3 alphas to "bootstrap" the statistics. The _saved_alpha is the
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309 // real value, but is used only after the first period. A value of 100 is
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310 // used for the first sample so it gets the entire weight.
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311 unsigned int _saved_alpha; // 0-100
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312 unsigned int _gc0_alpha;
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313 unsigned int _cms_alpha;
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314
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315 double _gc0_duration;
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316 double _gc0_period;
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317 size_t _gc0_promoted; // bytes promoted per gc0
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318 double _cms_duration;
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319 double _cms_duration_pre_sweep; // time from initiation to start of sweep
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320 double _cms_duration_per_mb;
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321 double _cms_period;
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322 size_t _cms_allocated; // bytes of direct allocation per gc0 period
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323
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324 // Timers.
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325 elapsedTimer _cms_timer;
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326 TimeStamp _gc0_begin_time;
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327 TimeStamp _cms_begin_time;
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328 TimeStamp _cms_end_time;
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329
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330 // Snapshots of the amount used in the CMS generation.
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331 size_t _cms_used_at_gc0_begin;
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332 size_t _cms_used_at_gc0_end;
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333 size_t _cms_used_at_cms_begin;
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334
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335 // Used to prevent the duty cycle from being reduced in the middle of a cms
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336 // cycle.
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337 bool _allow_duty_cycle_reduction;
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338
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339 enum {
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340 _GC0_VALID = 0x1,
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341 _CMS_VALID = 0x2,
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342 _ALL_VALID = _GC0_VALID | _CMS_VALID
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343 };
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344
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345 unsigned int _valid_bits;
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346
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347 unsigned int _icms_duty_cycle; // icms duty cycle (0-100).
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348
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349 protected:
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350
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351 // Return a duty cycle that avoids wild oscillations, by limiting the amount
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352 // of change between old_duty_cycle and new_duty_cycle (the latter is treated
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353 // as a recommended value).
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354 static unsigned int icms_damped_duty_cycle(unsigned int old_duty_cycle,
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355 unsigned int new_duty_cycle);
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356 unsigned int icms_update_duty_cycle_impl();
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357
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358 public:
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359 CMSStats(ConcurrentMarkSweepGeneration* cms_gen,
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360 unsigned int alpha = CMSExpAvgFactor);
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361
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362 // Whether or not the statistics contain valid data; higher level statistics
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363 // cannot be called until this returns true (they require at least one young
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364 // gen and one cms cycle to have completed).
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365 bool valid() const;
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366
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367 // Record statistics.
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368 void record_gc0_begin();
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369 void record_gc0_end(size_t cms_gen_bytes_used);
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370 void record_cms_begin();
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371 void record_cms_end();
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372
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373 // Allow management of the cms timer, which must be stopped/started around
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374 // yield points.
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375 elapsedTimer& cms_timer() { return _cms_timer; }
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376 void start_cms_timer() { _cms_timer.start(); }
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377 void stop_cms_timer() { _cms_timer.stop(); }
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378
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379 // Basic statistics; units are seconds or bytes.
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380 double gc0_period() const { return _gc0_period; }
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381 double gc0_duration() const { return _gc0_duration; }
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382 size_t gc0_promoted() const { return _gc0_promoted; }
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383 double cms_period() const { return _cms_period; }
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384 double cms_duration() const { return _cms_duration; }
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385 double cms_duration_per_mb() const { return _cms_duration_per_mb; }
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386 size_t cms_allocated() const { return _cms_allocated; }
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387
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388 size_t cms_used_at_gc0_end() const { return _cms_used_at_gc0_end;}
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389
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390 // Seconds since the last background cms cycle began or ended.
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391 double cms_time_since_begin() const;
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392 double cms_time_since_end() const;
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393
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394 // Higher level statistics--caller must check that valid() returns true before
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395 // calling.
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396
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397 // Returns bytes promoted per second of wall clock time.
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398 double promotion_rate() const;
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399
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|
400 // Returns bytes directly allocated per second of wall clock time.
|
|
|
401 double cms_allocation_rate() const;
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402
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|
403 // Rate at which space in the cms generation is being consumed (sum of the
|
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|
404 // above two).
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|
405 double cms_consumption_rate() const;
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406
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|
407 // Returns an estimate of the number of seconds until the cms generation will
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|
|
408 // fill up, assuming no collection work is done.
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|
409 double time_until_cms_gen_full() const;
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410
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|
411 // Returns an estimate of the number of seconds remaining until
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|
412 // the cms generation collection should start.
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|
413 double time_until_cms_start() const;
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414
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|
415 // End of higher level statistics.
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416
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417 // Returns the cms incremental mode duty cycle, as a percentage (0-100).
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418 unsigned int icms_duty_cycle() const { return _icms_duty_cycle; }
|
|
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419
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|
|
420 // Update the duty cycle and return the new value.
|
|
|
421 unsigned int icms_update_duty_cycle();
|
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422
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|
423 // Debugging.
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424 void print_on(outputStream* st) const PRODUCT_RETURN;
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|
425 void print() const { print_on(gclog_or_tty); }
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426 };
|
|
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427
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|
428 // A closure related to weak references processing which
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|
429 // we embed in the CMSCollector, since we need to pass
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|
430 // it to the reference processor for secondary filtering
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431 // of references based on reachability of referent;
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432 // see role of _is_alive_non_header closure in the
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433 // ReferenceProcessor class.
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434 // For objects in the CMS generation, this closure checks
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435 // if the object is "live" (reachable). Used in weak
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436 // reference processing.
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437 class CMSIsAliveClosure: public BoolObjectClosure {
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438 MemRegion _span;
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439 const CMSBitMap* _bit_map;
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440
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441 friend class CMSCollector;
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442 protected:
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443 void set_span(MemRegion span) { _span = span; }
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444 public:
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445 CMSIsAliveClosure(CMSBitMap* bit_map):
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446 _bit_map(bit_map) { }
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447
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448 CMSIsAliveClosure(MemRegion span,
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449 CMSBitMap* bit_map):
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450 _span(span),
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451 _bit_map(bit_map) { }
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|
452 void do_object(oop obj) {
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|
453 assert(false, "not to be invoked");
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|
454 }
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|
|
455 bool do_object_b(oop obj);
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|
456 };
|
|
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457
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458
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|
459 // Implements AbstractRefProcTaskExecutor for CMS.
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|
460 class CMSRefProcTaskExecutor: public AbstractRefProcTaskExecutor {
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461 public:
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462
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|
|
463 CMSRefProcTaskExecutor(CMSCollector& collector)
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464 : _collector(collector)
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|
465 { }
|
|
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466
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|
|
467 // Executes a task using worker threads.
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|
468 virtual void execute(ProcessTask& task);
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|
469 virtual void execute(EnqueueTask& task);
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470 private:
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|
|
471 CMSCollector& _collector;
|
|
|
472 };
|
|
|
473
|
|
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474
|
|
|
475 class CMSCollector: public CHeapObj {
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|
476 friend class VMStructs;
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|
|
477 friend class ConcurrentMarkSweepThread;
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|
|
478 friend class ConcurrentMarkSweepGeneration;
|
|
|
479 friend class CompactibleFreeListSpace;
|
|
|
480 friend class CMSParRemarkTask;
|
|
|
481 friend class CMSConcMarkingTask;
|
|
|
482 friend class CMSRefProcTaskProxy;
|
|
|
483 friend class CMSRefProcTaskExecutor;
|
|
|
484 friend class ScanMarkedObjectsAgainCarefullyClosure; // for sampling eden
|
|
|
485 friend class SurvivorSpacePrecleanClosure; // --- ditto -------
|
|
|
486 friend class PushOrMarkClosure; // to access _restart_addr
|
|
|
487 friend class Par_PushOrMarkClosure; // to access _restart_addr
|
|
|
488 friend class MarkFromRootsClosure; // -- ditto --
|
|
|
489 // ... and for clearing cards
|
|
|
490 friend class Par_MarkFromRootsClosure; // to access _restart_addr
|
|
|
491 // ... and for clearing cards
|
|
|
492 friend class Par_ConcMarkingClosure; // to access _restart_addr etc.
|
|
|
493 friend class MarkFromRootsVerifyClosure; // to access _restart_addr
|
|
|
494 friend class PushAndMarkVerifyClosure; // -- ditto --
|
|
|
495 friend class MarkRefsIntoAndScanClosure; // to access _overflow_list
|
|
|
496 friend class PushAndMarkClosure; // -- ditto --
|
|
|
497 friend class Par_PushAndMarkClosure; // -- ditto --
|
|
|
498 friend class CMSKeepAliveClosure; // -- ditto --
|
|
|
499 friend class CMSDrainMarkingStackClosure; // -- ditto --
|
|
|
500 friend class CMSInnerParMarkAndPushClosure; // -- ditto --
|
|
|
501 NOT_PRODUCT(friend class ScanMarkedObjectsAgainClosure;) // assertion on _overflow_list
|
|
|
502 friend class ReleaseForegroundGC; // to access _foregroundGCShouldWait
|
|
|
503 friend class VM_CMS_Operation;
|
|
|
504 friend class VM_CMS_Initial_Mark;
|
|
|
505 friend class VM_CMS_Final_Remark;
|
|
|
506
|
|
|
507 private:
|
|
|
508 jlong _time_of_last_gc;
|
|
|
509 void update_time_of_last_gc(jlong now) {
|
|
|
510 _time_of_last_gc = now;
|
|
|
511 }
|
|
|
512
|
|
|
513 OopTaskQueueSet* _task_queues;
|
|
|
514
|
|
|
515 // Overflow list of grey objects, threaded through mark-word
|
|
|
516 // Manipulated with CAS in the parallel/multi-threaded case.
|
|
|
517 oop _overflow_list;
|
|
|
518 // The following array-pair keeps track of mark words
|
|
|
519 // displaced for accomodating overflow list above.
|
|
|
520 // This code will likely be revisited under RFE#4922830.
|
|
|
521 GrowableArray<oop>* _preserved_oop_stack;
|
|
|
522 GrowableArray<markOop>* _preserved_mark_stack;
|
|
|
523
|
|
|
524 int* _hash_seed;
|
|
|
525
|
|
|
526 // In support of multi-threaded concurrent phases
|
|
|
527 YieldingFlexibleWorkGang* _conc_workers;
|
|
|
528
|
|
|
529 // Performance Counters
|
|
|
530 CollectorCounters* _gc_counters;
|
|
|
531
|
|
|
532 // Initialization Errors
|
|
|
533 bool _completed_initialization;
|
|
|
534
|
|
|
535 // In support of ExplicitGCInvokesConcurrent
|
|
|
536 static bool _full_gc_requested;
|
|
|
537 unsigned int _collection_count_start;
|
|
|
538 // Should we unload classes this concurrent cycle?
|
|
|
539 // Set in response to a concurrent full gc request.
|
|
|
540 bool _unload_classes;
|
|
|
541 bool _unloaded_classes_last_cycle;
|
|
|
542 // Did we (allow) unload classes in the previous concurrent cycle?
|
|
|
543 bool cms_unloaded_classes_last_cycle() const {
|
|
|
544 return _unloaded_classes_last_cycle || CMSClassUnloadingEnabled;
|
|
|
545 }
|
|
|
546
|
|
|
547 // Verification support
|
|
|
548 CMSBitMap _verification_mark_bm;
|
|
|
549 void verify_after_remark_work_1();
|
|
|
550 void verify_after_remark_work_2();
|
|
|
551
|
|
|
552 // true if any verification flag is on.
|
|
|
553 bool _verifying;
|
|
|
554 bool verifying() const { return _verifying; }
|
|
|
555 void set_verifying(bool v) { _verifying = v; }
|
|
|
556
|
|
|
557 // Collector policy
|
|
|
558 ConcurrentMarkSweepPolicy* _collector_policy;
|
|
|
559 ConcurrentMarkSweepPolicy* collector_policy() { return _collector_policy; }
|
|
|
560
|
|
|
561 // Check whether the gc time limit has been
|
|
|
562 // exceeded and set the size policy flag
|
|
|
563 // appropriately.
|
|
|
564 void check_gc_time_limit();
|
|
|
565 // XXX Move these to CMSStats ??? FIX ME !!!
|
|
|
566 elapsedTimer _sweep_timer;
|
|
|
567 AdaptivePaddedAverage _sweep_estimate;
|
|
|
568
|
|
|
569 protected:
|
|
|
570 ConcurrentMarkSweepGeneration* _cmsGen; // old gen (CMS)
|
|
|
571 ConcurrentMarkSweepGeneration* _permGen; // perm gen
|
|
|
572 MemRegion _span; // span covering above two
|
|
|
573 CardTableRS* _ct; // card table
|
|
|
574
|
|
|
575 // CMS marking support structures
|
|
|
576 CMSBitMap _markBitMap;
|
|
|
577 CMSBitMap _modUnionTable;
|
|
|
578 CMSMarkStack _markStack;
|
|
|
579 CMSMarkStack _revisitStack; // used to keep track of klassKlass objects
|
|
|
580 // to revisit
|
|
|
581 CMSBitMap _perm_gen_verify_bit_map; // Mark bit map for perm gen verification support.
|
|
|
582
|
|
|
583 HeapWord* _restart_addr; // in support of marking stack overflow
|
|
|
584 void lower_restart_addr(HeapWord* low);
|
|
|
585
|
|
|
586 // Counters in support of marking stack / work queue overflow handling:
|
|
|
587 // a non-zero value indicates certain types of overflow events during
|
|
|
588 // the current CMS cycle and could lead to stack resizing efforts at
|
|
|
589 // an opportune future time.
|
|
|
590 size_t _ser_pmc_preclean_ovflw;
|
|
|
591 size_t _ser_pmc_remark_ovflw;
|
|
|
592 size_t _par_pmc_remark_ovflw;
|
|
|
593 size_t _ser_kac_ovflw;
|
|
|
594 size_t _par_kac_ovflw;
|
|
|
595 NOT_PRODUCT(size_t _num_par_pushes;)
|
|
|
596
|
|
|
597 // ("Weak") Reference processing support
|
|
|
598 ReferenceProcessor* _ref_processor;
|
|
|
599 CMSIsAliveClosure _is_alive_closure;
|
|
|
600 // keep this textually after _markBitMap; c'tor dependency
|
|
|
601
|
|
|
602 ConcurrentMarkSweepThread* _cmsThread; // the thread doing the work
|
|
|
603 ModUnionClosure _modUnionClosure;
|
|
|
604 ModUnionClosurePar _modUnionClosurePar;
|
|
|
605
|
|
|
606 // CMS abstract state machine
|
|
|
607 // initial_state: Idling
|
|
|
608 // next_state(Idling) = {Marking}
|
|
|
609 // next_state(Marking) = {Precleaning, Sweeping}
|
|
|
610 // next_state(Precleaning) = {AbortablePreclean, FinalMarking}
|
|
|
611 // next_state(AbortablePreclean) = {FinalMarking}
|
|
|
612 // next_state(FinalMarking) = {Sweeping}
|
|
|
613 // next_state(Sweeping) = {Resizing}
|
|
|
614 // next_state(Resizing) = {Resetting}
|
|
|
615 // next_state(Resetting) = {Idling}
|
|
|
616 // The numeric values below are chosen so that:
|
|
|
617 // . _collectorState <= Idling == post-sweep && pre-mark
|
|
|
618 // . _collectorState in (Idling, Sweeping) == {initial,final}marking ||
|
|
|
619 // precleaning || abortablePrecleanb
|
|
|
620 enum CollectorState {
|
|
|
621 Resizing = 0,
|
|
|
622 Resetting = 1,
|
|
|
623 Idling = 2,
|
|
|
624 InitialMarking = 3,
|
|
|
625 Marking = 4,
|
|
|
626 Precleaning = 5,
|
|
|
627 AbortablePreclean = 6,
|
|
|
628 FinalMarking = 7,
|
|
|
629 Sweeping = 8
|
|
|
630 };
|
|
|
631 static CollectorState _collectorState;
|
|
|
632
|
|
|
633 // State related to prologue/epilogue invocation for my generations
|
|
|
634 bool _between_prologue_and_epilogue;
|
|
|
635
|
|
|
636 // Signalling/State related to coordination between fore- and backgroud GC
|
|
|
637 // Note: When the baton has been passed from background GC to foreground GC,
|
|
|
638 // _foregroundGCIsActive is true and _foregroundGCShouldWait is false.
|
|
|
639 static bool _foregroundGCIsActive; // true iff foreground collector is active or
|
|
|
640 // wants to go active
|
|
|
641 static bool _foregroundGCShouldWait; // true iff background GC is active and has not
|
|
|
642 // yet passed the baton to the foreground GC
|
|
|
643
|
|
|
644 // Support for CMSScheduleRemark (abortable preclean)
|
|
|
645 bool _abort_preclean;
|
|
|
646 bool _start_sampling;
|
|
|
647
|
|
|
648 int _numYields;
|
|
|
649 size_t _numDirtyCards;
|
|
|
650 uint _sweepCount;
|
|
|
651 // number of full gc's since the last concurrent gc.
|
|
|
652 uint _full_gcs_since_conc_gc;
|
|
|
653
|
|
|
654 // if occupancy exceeds this, start a new gc cycle
|
|
|
655 double _initiatingOccupancy;
|
|
|
656 // occupancy used for bootstrapping stats
|
|
|
657 double _bootstrap_occupancy;
|
|
|
658
|
|
|
659 // timer
|
|
|
660 elapsedTimer _timer;
|
|
|
661
|
|
|
662 // Timing, allocation and promotion statistics, used for scheduling.
|
|
|
663 CMSStats _stats;
|
|
|
664
|
|
|
665 // Allocation limits installed in the young gen, used only in
|
|
|
666 // CMSIncrementalMode. When an allocation in the young gen would cross one of
|
|
|
667 // these limits, the cms generation is notified and the cms thread is started
|
|
|
668 // or stopped, respectively.
|
|
|
669 HeapWord* _icms_start_limit;
|
|
|
670 HeapWord* _icms_stop_limit;
|
|
|
671
|
|
|
672 enum CMS_op_type {
|
|
|
673 CMS_op_checkpointRootsInitial,
|
|
|
674 CMS_op_checkpointRootsFinal
|
|
|
675 };
|
|
|
676
|
|
|
677 void do_CMS_operation(CMS_op_type op);
|
|
|
678 bool stop_world_and_do(CMS_op_type op);
|
|
|
679
|
|
|
680 OopTaskQueueSet* task_queues() { return _task_queues; }
|
|
|
681 int* hash_seed(int i) { return &_hash_seed[i]; }
|
|
|
682 YieldingFlexibleWorkGang* conc_workers() { return _conc_workers; }
|
|
|
683
|
|
|
684 // Support for parallelizing Eden rescan in CMS remark phase
|
|
|
685 void sample_eden(); // ... sample Eden space top
|
|
|
686
|
|
|
687 private:
|
|
|
688 // Support for parallelizing young gen rescan in CMS remark phase
|
|
|
689 Generation* _young_gen; // the younger gen
|
|
|
690 HeapWord** _top_addr; // ... Top of Eden
|
|
|
691 HeapWord** _end_addr; // ... End of Eden
|
|
|
692 HeapWord** _eden_chunk_array; // ... Eden partitioning array
|
|
|
693 size_t _eden_chunk_index; // ... top (exclusive) of array
|
|
|
694 size_t _eden_chunk_capacity; // ... max entries in array
|
|
|
695
|
|
|
696 // Support for parallelizing survivor space rescan
|
|
|
697 HeapWord** _survivor_chunk_array;
|
|
|
698 size_t _survivor_chunk_index;
|
|
|
699 size_t _survivor_chunk_capacity;
|
|
|
700 size_t* _cursor;
|
|
|
701 ChunkArray* _survivor_plab_array;
|
|
|
702
|
|
|
703 // Support for marking stack overflow handling
|
|
|
704 bool take_from_overflow_list(size_t num, CMSMarkStack* to_stack);
|
|
|
705 bool par_take_from_overflow_list(size_t num, OopTaskQueue* to_work_q);
|
|
|
706 void push_on_overflow_list(oop p);
|
|
|
707 void par_push_on_overflow_list(oop p);
|
|
|
708 // the following is, obviously, not, in general, "MT-stable"
|
|
|
709 bool overflow_list_is_empty() const;
|
|
|
710
|
|
|
711 void preserve_mark_if_necessary(oop p);
|
|
|
712 void par_preserve_mark_if_necessary(oop p);
|
|
|
713 void preserve_mark_work(oop p, markOop m);
|
|
|
714 void restore_preserved_marks_if_any();
|
|
|
715 NOT_PRODUCT(bool no_preserved_marks() const;)
|
|
|
716 // in support of testing overflow code
|
|
|
717 NOT_PRODUCT(int _overflow_counter;)
|
|
|
718 NOT_PRODUCT(bool simulate_overflow();) // sequential
|
|
|
719 NOT_PRODUCT(bool par_simulate_overflow();) // MT version
|
|
|
720
|
|
|
721 int _roots_scanning_options;
|
|
|
722 int roots_scanning_options() const { return _roots_scanning_options; }
|
|
|
723 void add_root_scanning_option(int o) { _roots_scanning_options |= o; }
|
|
|
724 void remove_root_scanning_option(int o) { _roots_scanning_options &= ~o; }
|
|
|
725
|
|
|
726 // CMS work methods
|
|
|
727 void checkpointRootsInitialWork(bool asynch); // initial checkpoint work
|
|
|
728
|
|
|
729 // a return value of false indicates failure due to stack overflow
|
|
|
730 bool markFromRootsWork(bool asynch); // concurrent marking work
|
|
|
731
|
|
|
732 public: // FIX ME!!! only for testing
|
|
|
733 bool do_marking_st(bool asynch); // single-threaded marking
|
|
|
734 bool do_marking_mt(bool asynch); // multi-threaded marking
|
|
|
735
|
|
|
736 private:
|
|
|
737
|
|
|
738 // concurrent precleaning work
|
|
|
739 size_t preclean_mod_union_table(ConcurrentMarkSweepGeneration* gen,
|
|
|
740 ScanMarkedObjectsAgainCarefullyClosure* cl);
|
|
|
741 size_t preclean_card_table(ConcurrentMarkSweepGeneration* gen,
|
|
|
742 ScanMarkedObjectsAgainCarefullyClosure* cl);
|
|
|
743 // Does precleaning work, returning a quantity indicative of
|
|
|
744 // the amount of "useful work" done.
|
|
|
745 size_t preclean_work(bool clean_refs, bool clean_survivors);
|
|
|
746 void abortable_preclean(); // Preclean while looking for possible abort
|
|
|
747 void initialize_sequential_subtasks_for_young_gen_rescan(int i);
|
|
|
748 // Helper function for above; merge-sorts the per-thread plab samples
|
|
|
749 void merge_survivor_plab_arrays(ContiguousSpace* surv);
|
|
|
750 // Resets (i.e. clears) the per-thread plab sample vectors
|
|
|
751 void reset_survivor_plab_arrays();
|
|
|
752
|
|
|
753 // final (second) checkpoint work
|
|
|
754 void checkpointRootsFinalWork(bool asynch, bool clear_all_soft_refs,
|
|
|
755 bool init_mark_was_synchronous);
|
|
|
756 // work routine for parallel version of remark
|
|
|
757 void do_remark_parallel();
|
|
|
758 // work routine for non-parallel version of remark
|
|
|
759 void do_remark_non_parallel();
|
|
|
760 // reference processing work routine (during second checkpoint)
|
|
|
761 void refProcessingWork(bool asynch, bool clear_all_soft_refs);
|
|
|
762
|
|
|
763 // concurrent sweeping work
|
|
|
764 void sweepWork(ConcurrentMarkSweepGeneration* gen, bool asynch);
|
|
|
765
|
|
|
766 // (concurrent) resetting of support data structures
|
|
|
767 void reset(bool asynch);
|
|
|
768
|
|
|
769 // Clear _expansion_cause fields of constituent generations
|
|
|
770 void clear_expansion_cause();
|
|
|
771
|
|
|
772 // An auxilliary method used to record the ends of
|
|
|
773 // used regions of each generation to limit the extent of sweep
|
|
|
774 void save_sweep_limits();
|
|
|
775
|
|
|
776 // Resize the generations included in the collector.
|
|
|
777 void compute_new_size();
|
|
|
778
|
|
|
779 // A work method used by foreground collection to determine
|
|
|
780 // what type of collection (compacting or not, continuing or fresh)
|
|
|
781 // it should do.
|
|
|
782 void decide_foreground_collection_type(bool clear_all_soft_refs,
|
|
|
783 bool* should_compact, bool* should_start_over);
|
|
|
784
|
|
|
785 // A work method used by the foreground collector to do
|
|
|
786 // a mark-sweep-compact.
|
|
|
787 void do_compaction_work(bool clear_all_soft_refs);
|
|
|
788
|
|
|
789 // A work method used by the foreground collector to do
|
|
|
790 // a mark-sweep, after taking over from a possibly on-going
|
|
|
791 // concurrent mark-sweep collection.
|
|
|
792 void do_mark_sweep_work(bool clear_all_soft_refs,
|
|
|
793 CollectorState first_state, bool should_start_over);
|
|
|
794
|
|
|
795 // If the backgrould GC is active, acquire control from the background
|
|
|
796 // GC and do the collection.
|
|
|
797 void acquire_control_and_collect(bool full, bool clear_all_soft_refs);
|
|
|
798
|
|
|
799 // For synchronizing passing of control from background to foreground
|
|
|
800 // GC. waitForForegroundGC() is called by the background
|
|
|
801 // collector. It if had to wait for a foreground collection,
|
|
|
802 // it returns true and the background collection should assume
|
|
|
803 // that the collection was finished by the foreground
|
|
|
804 // collector.
|
|
|
805 bool waitForForegroundGC();
|
|
|
806
|
|
|
807 // Incremental mode triggering: recompute the icms duty cycle and set the
|
|
|
808 // allocation limits in the young gen.
|
|
|
809 void icms_update_allocation_limits();
|
|
|
810
|
|
|
811 size_t block_size_using_printezis_bits(HeapWord* addr) const;
|
|
|
812 size_t block_size_if_printezis_bits(HeapWord* addr) const;
|
|
|
813 HeapWord* next_card_start_after_block(HeapWord* addr) const;
|
|
|
814
|
|
|
815 void setup_cms_unloading_and_verification_state();
|
|
|
816 public:
|
|
|
817 CMSCollector(ConcurrentMarkSweepGeneration* cmsGen,
|
|
|
818 ConcurrentMarkSweepGeneration* permGen,
|
|
|
819 CardTableRS* ct,
|
|
|
820 ConcurrentMarkSweepPolicy* cp);
|
|
|
821 ConcurrentMarkSweepThread* cmsThread() { return _cmsThread; }
|
|
|
822
|
|
|
823 ReferenceProcessor* ref_processor() { return _ref_processor; }
|
|
|
824 void ref_processor_init();
|
|
|
825
|
|
|
826 Mutex* bitMapLock() const { return _markBitMap.lock(); }
|
|
|
827 static CollectorState abstract_state() { return _collectorState; }
|
|
|
828 double initiatingOccupancy() const { return _initiatingOccupancy; }
|
|
|
829
|
|
|
830 bool should_abort_preclean() const; // Whether preclean should be aborted.
|
|
|
831 size_t get_eden_used() const;
|
|
|
832 size_t get_eden_capacity() const;
|
|
|
833
|
|
|
834 ConcurrentMarkSweepGeneration* cmsGen() { return _cmsGen; }
|
|
|
835
|
|
|
836 // locking checks
|
|
|
837 NOT_PRODUCT(static bool have_cms_token();)
|
|
|
838
|
|
|
839 // XXXPERM bool should_collect(bool full, size_t size, bool tlab);
|
|
|
840 bool shouldConcurrentCollect();
|
|
|
841
|
|
|
842 void collect(bool full,
|
|
|
843 bool clear_all_soft_refs,
|
|
|
844 size_t size,
|
|
|
845 bool tlab);
|
|
|
846 void collect_in_background(bool clear_all_soft_refs);
|
|
|
847 void collect_in_foreground(bool clear_all_soft_refs);
|
|
|
848
|
|
|
849 // In support of ExplicitGCInvokesConcurrent
|
|
|
850 static void request_full_gc(unsigned int full_gc_count);
|
|
|
851 // Should we unload classes in a particular concurrent cycle?
|
|
|
852 bool cms_should_unload_classes() const {
|
|
|
853 assert(!_unload_classes || ExplicitGCInvokesConcurrentAndUnloadsClasses,
|
|
|
854 "Inconsistency; see CR 6541037");
|
|
|
855 return _unload_classes || CMSClassUnloadingEnabled;
|
|
|
856 }
|
|
|
857
|
|
|
858 void direct_allocated(HeapWord* start, size_t size);
|
|
|
859
|
|
|
860 // Object is dead if not marked and current phase is sweeping.
|
|
|
861 bool is_dead_obj(oop obj) const;
|
|
|
862
|
|
|
863 // After a promotion (of "start"), do any necessary marking.
|
|
|
864 // If "par", then it's being done by a parallel GC thread.
|
|
|
865 // The last two args indicate if we need precise marking
|
|
|
866 // and if so the size of the object so it can be dirtied
|
|
|
867 // in its entirety.
|
|
|
868 void promoted(bool par, HeapWord* start,
|
|
|
869 bool is_obj_array, size_t obj_size);
|
|
|
870
|
|
|
871 HeapWord* allocation_limit_reached(Space* space, HeapWord* top,
|
|
|
872 size_t word_size);
|
|
|
873
|
|
|
874 void getFreelistLocks() const;
|
|
|
875 void releaseFreelistLocks() const;
|
|
|
876 bool haveFreelistLocks() const;
|
|
|
877
|
|
|
878 // GC prologue and epilogue
|
|
|
879 void gc_prologue(bool full);
|
|
|
880 void gc_epilogue(bool full);
|
|
|
881
|
|
|
882 jlong time_of_last_gc(jlong now) {
|
|
|
883 if (_collectorState <= Idling) {
|
|
|
884 // gc not in progress
|
|
|
885 return _time_of_last_gc;
|
|
|
886 } else {
|
|
|
887 // collection in progress
|
|
|
888 return now;
|
|
|
889 }
|
|
|
890 }
|
|
|
891
|
|
|
892 // Support for parallel remark of survivor space
|
|
|
893 void* get_data_recorder(int thr_num);
|
|
|
894
|
|
|
895 CMSBitMap* markBitMap() { return &_markBitMap; }
|
|
|
896 void directAllocated(HeapWord* start, size_t size);
|
|
|
897
|
|
|
898 // main CMS steps and related support
|
|
|
899 void checkpointRootsInitial(bool asynch);
|
|
|
900 bool markFromRoots(bool asynch); // a return value of false indicates failure
|
|
|
901 // due to stack overflow
|
|
|
902 void preclean();
|
|
|
903 void checkpointRootsFinal(bool asynch, bool clear_all_soft_refs,
|
|
|
904 bool init_mark_was_synchronous);
|
|
|
905 void sweep(bool asynch);
|
|
|
906
|
|
|
907 // Check that the currently executing thread is the expected
|
|
|
908 // one (foreground collector or background collector).
|
|
|
909 void check_correct_thread_executing() PRODUCT_RETURN;
|
|
|
910 // XXXPERM void print_statistics() PRODUCT_RETURN;
|
|
|
911
|
|
|
912 bool is_cms_reachable(HeapWord* addr);
|
|
|
913
|
|
|
914 // Performance Counter Support
|
|
|
915 CollectorCounters* counters() { return _gc_counters; }
|
|
|
916
|
|
|
917 // timer stuff
|
|
|
918 void startTimer() { assert(!_timer.is_active(), "Error"); _timer.start(); }
|
|
|
919 void stopTimer() { assert( _timer.is_active(), "Error"); _timer.stop(); }
|
|
|
920 void resetTimer() { assert(!_timer.is_active(), "Error"); _timer.reset(); }
|
|
|
921 double timerValue() { assert(!_timer.is_active(), "Error"); return _timer.seconds(); }
|
|
|
922
|
|
|
923 int yields() { return _numYields; }
|
|
|
924 void resetYields() { _numYields = 0; }
|
|
|
925 void incrementYields() { _numYields++; }
|
|
|
926 void resetNumDirtyCards() { _numDirtyCards = 0; }
|
|
|
927 void incrementNumDirtyCards(size_t num) { _numDirtyCards += num; }
|
|
|
928 size_t numDirtyCards() { return _numDirtyCards; }
|
|
|
929
|
|
|
930 static bool foregroundGCShouldWait() { return _foregroundGCShouldWait; }
|
|
|
931 static void set_foregroundGCShouldWait(bool v) { _foregroundGCShouldWait = v; }
|
|
|
932 static bool foregroundGCIsActive() { return _foregroundGCIsActive; }
|
|
|
933 static void set_foregroundGCIsActive(bool v) { _foregroundGCIsActive = v; }
|
|
|
934 uint sweepCount() const { return _sweepCount; }
|
|
|
935 void incrementSweepCount() { _sweepCount++; }
|
|
|
936
|
|
|
937 // Timers/stats for gc scheduling and incremental mode pacing.
|
|
|
938 CMSStats& stats() { return _stats; }
|
|
|
939
|
|
|
940 // Convenience methods that check whether CMSIncrementalMode is enabled and
|
|
|
941 // forward to the corresponding methods in ConcurrentMarkSweepThread.
|
|
|
942 static void start_icms();
|
|
|
943 static void stop_icms(); // Called at the end of the cms cycle.
|
|
|
944 static void disable_icms(); // Called before a foreground collection.
|
|
|
945 static void enable_icms(); // Called after a foreground collection.
|
|
|
946 void icms_wait(); // Called at yield points.
|
|
|
947
|
|
|
948 // Adaptive size policy
|
|
|
949 CMSAdaptiveSizePolicy* size_policy();
|
|
|
950 CMSGCAdaptivePolicyCounters* gc_adaptive_policy_counters();
|
|
|
951
|
|
|
952 // debugging
|
|
|
953 void verify(bool);
|
|
|
954 bool verify_after_remark();
|
|
|
955 void verify_ok_to_terminate() const PRODUCT_RETURN;
|
|
|
956 void verify_work_stacks_empty() const PRODUCT_RETURN;
|
|
|
957 void verify_overflow_empty() const PRODUCT_RETURN;
|
|
|
958
|
|
|
959 // convenience methods in support of debugging
|
|
|
960 static const size_t skip_header_HeapWords() PRODUCT_RETURN0;
|
|
|
961 HeapWord* block_start(const void* p) const PRODUCT_RETURN0;
|
|
|
962
|
|
|
963 // accessors
|
|
|
964 CMSMarkStack* verification_mark_stack() { return &_markStack; }
|
|
|
965 CMSBitMap* verification_mark_bm() { return &_verification_mark_bm; }
|
|
|
966
|
|
|
967 // Get the bit map with a perm gen "deadness" information.
|
|
|
968 CMSBitMap* perm_gen_verify_bit_map() { return &_perm_gen_verify_bit_map; }
|
|
|
969
|
|
|
970 // Initialization errors
|
|
|
971 bool completed_initialization() { return _completed_initialization; }
|
|
|
972 };
|
|
|
973
|
|
|
974 class CMSExpansionCause : public AllStatic {
|
|
|
975 public:
|
|
|
976 enum Cause {
|
|
|
977 _no_expansion,
|
|
|
978 _satisfy_free_ratio,
|
|
|
979 _satisfy_promotion,
|
|
|
980 _satisfy_allocation,
|
|
|
981 _allocate_par_lab,
|
|
|
982 _allocate_par_spooling_space,
|
|
|
983 _adaptive_size_policy
|
|
|
984 };
|
|
|
985 // Return a string describing the cause of the expansion.
|
|
|
986 static const char* to_string(CMSExpansionCause::Cause cause);
|
|
|
987 };
|
|
|
988
|
|
|
989 class ConcurrentMarkSweepGeneration: public CardGeneration {
|
|
|
990 friend class VMStructs;
|
|
|
991 friend class ConcurrentMarkSweepThread;
|
|
|
992 friend class ConcurrentMarkSweep;
|
|
|
993 friend class CMSCollector;
|
|
|
994 protected:
|
|
|
995 static CMSCollector* _collector; // the collector that collects us
|
|
|
996 CompactibleFreeListSpace* _cmsSpace; // underlying space (only one for now)
|
|
|
997
|
|
|
998 // Performance Counters
|
|
|
999 GenerationCounters* _gen_counters;
|
|
|
1000 GSpaceCounters* _space_counters;
|
|
|
1001
|
|
|
1002 // Words directly allocated, used by CMSStats.
|
|
|
1003 size_t _direct_allocated_words;
|
|
|
1004
|
|
|
1005 // Non-product stat counters
|
|
|
1006 NOT_PRODUCT(
|
|
|
1007 int _numObjectsPromoted;
|
|
|
1008 int _numWordsPromoted;
|
|
|
1009 int _numObjectsAllocated;
|
|
|
1010 int _numWordsAllocated;
|
|
|
1011 )
|
|
|
1012
|
|
|
1013 // Used for sizing decisions
|
|
|
1014 bool _incremental_collection_failed;
|
|
|
1015 bool incremental_collection_failed() {
|
|
|
1016 return _incremental_collection_failed;
|
|
|
1017 }
|
|
|
1018 void set_incremental_collection_failed() {
|
|
|
1019 _incremental_collection_failed = true;
|
|
|
1020 }
|
|
|
1021 void clear_incremental_collection_failed() {
|
|
|
1022 _incremental_collection_failed = false;
|
|
|
1023 }
|
|
|
1024
|
|
|
1025 private:
|
|
|
1026 // For parallel young-gen GC support.
|
|
|
1027 CMSParGCThreadState** _par_gc_thread_states;
|
|
|
1028
|
|
|
1029 // Reason generation was expanded
|
|
|
1030 CMSExpansionCause::Cause _expansion_cause;
|
|
|
1031
|
|
|
1032 // accessors
|
|
|
1033 void set_expansion_cause(CMSExpansionCause::Cause v) { _expansion_cause = v;}
|
|
|
1034 CMSExpansionCause::Cause expansion_cause() { return _expansion_cause; }
|
|
|
1035
|
|
|
1036 // In support of MinChunkSize being larger than min object size
|
|
|
1037 const double _dilatation_factor;
|
|
|
1038
|
|
|
1039 enum CollectionTypes {
|
|
|
1040 Concurrent_collection_type = 0,
|
|
|
1041 MS_foreground_collection_type = 1,
|
|
|
1042 MSC_foreground_collection_type = 2,
|
|
|
1043 Unknown_collection_type = 3
|
|
|
1044 };
|
|
|
1045
|
|
|
1046 CollectionTypes _debug_collection_type;
|
|
|
1047
|
|
|
1048 protected:
|
|
|
1049 // Grow generation by specified size (returns false if unable to grow)
|
|
|
1050 bool grow_by(size_t bytes);
|
|
|
1051 // Grow generation to reserved size.
|
|
|
1052 bool grow_to_reserved();
|
|
|
1053 // Shrink generation by specified size (returns false if unable to shrink)
|
|
|
1054 virtual void shrink_by(size_t bytes);
|
|
|
1055
|
|
|
1056 // Update statistics for GC
|
|
|
1057 virtual void update_gc_stats(int level, bool full);
|
|
|
1058
|
|
|
1059 // Maximum available space in the generation (including uncommitted)
|
|
|
1060 // space.
|
|
|
1061 size_t max_available() const;
|
|
|
1062
|
|
|
1063 public:
|
|
|
1064 ConcurrentMarkSweepGeneration(ReservedSpace rs, size_t initial_byte_size,
|
|
|
1065 int level, CardTableRS* ct,
|
|
|
1066 bool use_adaptive_freelists,
|
|
|
1067 FreeBlockDictionary::DictionaryChoice);
|
|
|
1068
|
|
|
1069 // Accessors
|
|
|
1070 CMSCollector* collector() const { return _collector; }
|
|
|
1071 static void set_collector(CMSCollector* collector) {
|
|
|
1072 assert(_collector == NULL, "already set");
|
|
|
1073 _collector = collector;
|
|
|
1074 }
|
|
|
1075 CompactibleFreeListSpace* cmsSpace() const { return _cmsSpace; }
|
|
|
1076
|
|
|
1077 Mutex* freelistLock() const;
|
|
|
1078
|
|
|
1079 virtual Generation::Name kind() { return Generation::ConcurrentMarkSweep; }
|
|
|
1080
|
|
|
1081 // Adaptive size policy
|
|
|
1082 CMSAdaptiveSizePolicy* size_policy();
|
|
|
1083
|
|
|
1084 bool refs_discovery_is_atomic() const { return false; }
|
|
|
1085 bool refs_discovery_is_mt() const {
|
|
|
1086 // Note: CMS does MT-discovery during the parallel-remark
|
|
|
1087 // phases. Use ReferenceProcessorMTMutator to make refs
|
|
|
1088 // discovery MT-safe during such phases or other parallel
|
|
|
1089 // discovery phases in the future. This may all go away
|
|
|
1090 // if/when we decide that refs discovery is sufficiently
|
|
|
1091 // rare that the cost of the CAS's involved is in the
|
|
|
1092 // noise. That's a measurement that should be done, and
|
|
|
1093 // the code simplified if that turns out to be the case.
|
|
|
1094 return false;
|
|
|
1095 }
|
|
|
1096
|
|
|
1097 // Override
|
|
|
1098 virtual void ref_processor_init();
|
|
|
1099
|
|
|
1100 void clear_expansion_cause() { _expansion_cause = CMSExpansionCause::_no_expansion; }
|
|
|
1101
|
|
|
1102 // Space enquiries
|
|
|
1103 size_t capacity() const;
|
|
|
1104 size_t used() const;
|
|
|
1105 size_t free() const;
|
|
|
1106 double occupancy() { return ((double)used())/((double)capacity()); }
|
|
|
1107 size_t contiguous_available() const;
|
|
|
1108 size_t unsafe_max_alloc_nogc() const;
|
|
|
1109
|
|
|
1110 // over-rides
|
|
|
1111 MemRegion used_region() const;
|
|
|
1112 MemRegion used_region_at_save_marks() const;
|
|
|
1113
|
|
|
1114 // Does a "full" (forced) collection invoked on this generation collect
|
|
|
1115 // all younger generations as well? Note that the second conjunct is a
|
|
|
1116 // hack to allow the collection of the younger gen first if the flag is
|
|
|
1117 // set. This is better than using th policy's should_collect_gen0_first()
|
|
|
1118 // since that causes us to do an extra unnecessary pair of restart-&-stop-world.
|
|
|
1119 virtual bool full_collects_younger_generations() const {
|
|
|
1120 return UseCMSCompactAtFullCollection && !CollectGen0First;
|
|
|
1121 }
|
|
|
1122
|
|
|
1123 void space_iterate(SpaceClosure* blk, bool usedOnly = false);
|
|
|
1124
|
|
|
1125 // Support for compaction
|
|
|
1126 CompactibleSpace* first_compaction_space() const;
|
|
|
1127 // Adjust quantites in the generation affected by
|
|
|
1128 // the compaction.
|
|
|
1129 void reset_after_compaction();
|
|
|
1130
|
|
|
1131 // Allocation support
|
|
|
1132 HeapWord* allocate(size_t size, bool tlab);
|
|
|
1133 HeapWord* have_lock_and_allocate(size_t size, bool tlab);
|
|
|
1134 oop promote(oop obj, size_t obj_size, oop* ref);
|
|
|
1135 HeapWord* par_allocate(size_t size, bool tlab) {
|
|
|
1136 return allocate(size, tlab);
|
|
|
1137 }
|
|
|
1138
|
|
|
1139 // Incremental mode triggering.
|
|
|
1140 HeapWord* allocation_limit_reached(Space* space, HeapWord* top,
|
|
|
1141 size_t word_size);
|
|
|
1142
|
|
|
1143 // Used by CMSStats to track direct allocation. The value is sampled and
|
|
|
1144 // reset after each young gen collection.
|
|
|
1145 size_t direct_allocated_words() const { return _direct_allocated_words; }
|
|
|
1146 void reset_direct_allocated_words() { _direct_allocated_words = 0; }
|
|
|
1147
|
|
|
1148 // Overrides for parallel promotion.
|
|
|
1149 virtual oop par_promote(int thread_num,
|
|
|
1150 oop obj, markOop m, size_t word_sz);
|
|
|
1151 // This one should not be called for CMS.
|
|
|
1152 virtual void par_promote_alloc_undo(int thread_num,
|
|
|
1153 HeapWord* obj, size_t word_sz);
|
|
|
1154 virtual void par_promote_alloc_done(int thread_num);
|
|
|
1155 virtual void par_oop_since_save_marks_iterate_done(int thread_num);
|
|
|
1156
|
|
|
1157 virtual bool promotion_attempt_is_safe(size_t promotion_in_bytes,
|
|
|
1158 bool younger_handles_promotion_failure) const;
|
|
|
1159
|
|
|
1160 bool should_collect(bool full, size_t size, bool tlab);
|
|
|
1161 // XXXPERM
|
|
|
1162 bool shouldConcurrentCollect(double initiatingOccupancy); // XXXPERM
|
|
|
1163 void collect(bool full,
|
|
|
1164 bool clear_all_soft_refs,
|
|
|
1165 size_t size,
|
|
|
1166 bool tlab);
|
|
|
1167
|
|
|
1168 HeapWord* expand_and_allocate(size_t word_size,
|
|
|
1169 bool tlab,
|
|
|
1170 bool parallel = false);
|
|
|
1171
|
|
|
1172 // GC prologue and epilogue
|
|
|
1173 void gc_prologue(bool full);
|
|
|
1174 void gc_prologue_work(bool full, bool registerClosure,
|
|
|
1175 ModUnionClosure* modUnionClosure);
|
|
|
1176 void gc_epilogue(bool full);
|
|
|
1177 void gc_epilogue_work(bool full);
|
|
|
1178
|
|
|
1179 // Time since last GC of this generation
|
|
|
1180 jlong time_of_last_gc(jlong now) {
|
|
|
1181 return collector()->time_of_last_gc(now);
|
|
|
1182 }
|
|
|
1183 void update_time_of_last_gc(jlong now) {
|
|
|
1184 collector()-> update_time_of_last_gc(now);
|
|
|
1185 }
|
|
|
1186
|
|
|
1187 // Allocation failure
|
|
|
1188 void expand(size_t bytes, size_t expand_bytes,
|
|
|
1189 CMSExpansionCause::Cause cause);
|
|
|
1190 void shrink(size_t bytes);
|
|
|
1191 HeapWord* expand_and_par_lab_allocate(CMSParGCThreadState* ps, size_t word_sz);
|
|
|
1192 bool expand_and_ensure_spooling_space(PromotionInfo* promo);
|
|
|
1193
|
|
|
1194 // Iteration support and related enquiries
|
|
|
1195 void save_marks();
|
|
|
1196 bool no_allocs_since_save_marks();
|
|
|
1197 void object_iterate_since_last_GC(ObjectClosure* cl);
|
|
|
1198 void younger_refs_iterate(OopsInGenClosure* cl);
|
|
|
1199
|
|
|
1200 // Iteration support specific to CMS generations
|
|
|
1201 void save_sweep_limit();
|
|
|
1202
|
|
|
1203 // More iteration support
|
|
|
1204 virtual void oop_iterate(MemRegion mr, OopClosure* cl);
|
|
|
1205 virtual void oop_iterate(OopClosure* cl);
|
|
|
1206 virtual void object_iterate(ObjectClosure* cl);
|
|
|
1207
|
|
|
1208 // Need to declare the full complement of closures, whether we'll
|
|
|
1209 // override them or not, or get message from the compiler:
|
|
|
1210 // oop_since_save_marks_iterate_nv hides virtual function...
|
|
|
1211 #define CMS_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
|
|
|
1212 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
|
|
|
1213 ALL_SINCE_SAVE_MARKS_CLOSURES(CMS_SINCE_SAVE_MARKS_DECL)
|
|
|
1214
|
|
|
1215 // Smart allocation XXX -- move to CFLSpace?
|
|
|
1216 void setNearLargestChunk();
|
|
|
1217 bool isNearLargestChunk(HeapWord* addr);
|
|
|
1218
|
|
|
1219 // Get the chunk at the end of the space. Delagates to
|
|
|
1220 // the space.
|
|
|
1221 FreeChunk* find_chunk_at_end();
|
|
|
1222
|
|
|
1223 // Overriding of unused functionality (sharing not yet supported with CMS)
|
|
|
1224 void pre_adjust_pointers();
|
|
|
1225 void post_compact();
|
|
|
1226
|
|
|
1227 // Debugging
|
|
|
1228 void prepare_for_verify();
|
|
|
1229 void verify(bool allow_dirty);
|
|
|
1230 void print_statistics() PRODUCT_RETURN;
|
|
|
1231
|
|
|
1232 // Performance Counters support
|
|
|
1233 virtual void update_counters();
|
|
|
1234 virtual void update_counters(size_t used);
|
|
|
1235 void initialize_performance_counters();
|
|
|
1236 CollectorCounters* counters() { return collector()->counters(); }
|
|
|
1237
|
|
|
1238 // Support for parallel remark of survivor space
|
|
|
1239 void* get_data_recorder(int thr_num) {
|
|
|
1240 //Delegate to collector
|
|
|
1241 return collector()->get_data_recorder(thr_num);
|
|
|
1242 }
|
|
|
1243
|
|
|
1244 // Printing
|
|
|
1245 const char* name() const;
|
|
|
1246 virtual const char* short_name() const { return "CMS"; }
|
|
|
1247 void print() const;
|
|
|
1248 void printOccupancy(const char* s);
|
|
|
1249 bool must_be_youngest() const { return false; }
|
|
|
1250 bool must_be_oldest() const { return true; }
|
|
|
1251
|
|
|
1252 void compute_new_size();
|
|
|
1253
|
|
|
1254 CollectionTypes debug_collection_type() { return _debug_collection_type; }
|
|
|
1255 void rotate_debug_collection_type();
|
|
|
1256 };
|
|
|
1257
|
|
|
1258 class ASConcurrentMarkSweepGeneration : public ConcurrentMarkSweepGeneration {
|
|
|
1259
|
|
|
1260 // Return the size policy from the heap's collector
|
|
|
1261 // policy casted to CMSAdaptiveSizePolicy*.
|
|
|
1262 CMSAdaptiveSizePolicy* cms_size_policy() const;
|
|
|
1263
|
|
|
1264 // Resize the generation based on the adaptive size
|
|
|
1265 // policy.
|
|
|
1266 void resize(size_t cur_promo, size_t desired_promo);
|
|
|
1267
|
|
|
1268 // Return the GC counters from the collector policy
|
|
|
1269 CMSGCAdaptivePolicyCounters* gc_adaptive_policy_counters();
|
|
|
1270
|
|
|
1271 virtual void shrink_by(size_t bytes);
|
|
|
1272
|
|
|
1273 public:
|
|
|
1274 virtual void compute_new_size();
|
|
|
1275 ASConcurrentMarkSweepGeneration(ReservedSpace rs, size_t initial_byte_size,
|
|
|
1276 int level, CardTableRS* ct,
|
|
|
1277 bool use_adaptive_freelists,
|
|
|
1278 FreeBlockDictionary::DictionaryChoice
|
|
|
1279 dictionaryChoice) :
|
|
|
1280 ConcurrentMarkSweepGeneration(rs, initial_byte_size, level, ct,
|
|
|
1281 use_adaptive_freelists, dictionaryChoice) {}
|
|
|
1282
|
|
|
1283 virtual const char* short_name() const { return "ASCMS"; }
|
|
|
1284 virtual Generation::Name kind() { return Generation::ASConcurrentMarkSweep; }
|
|
|
1285
|
|
|
1286 virtual void update_counters();
|
|
|
1287 virtual void update_counters(size_t used);
|
|
|
1288 };
|
|
|
1289
|
|
|
1290 //
|
|
|
1291 // Closures of various sorts used by CMS to accomplish its work
|
|
|
1292 //
|
|
|
1293
|
|
|
1294 // This closure is used to check that a certain set of oops is empty.
|
|
|
1295 class FalseClosure: public OopClosure {
|
|
|
1296 public:
|
|
|
1297 void do_oop(oop* p) {
|
|
|
1298 guarantee(false, "Should be an empty set");
|
|
|
1299 }
|
|
|
1300 };
|
|
|
1301
|
|
|
1302 // This closure is used to do concurrent marking from the roots
|
|
|
1303 // following the first checkpoint.
|
|
|
1304 class MarkFromRootsClosure: public BitMapClosure {
|
|
|
1305 CMSCollector* _collector;
|
|
|
1306 MemRegion _span;
|
|
|
1307 CMSBitMap* _bitMap;
|
|
|
1308 CMSBitMap* _mut;
|
|
|
1309 CMSMarkStack* _markStack;
|
|
|
1310 CMSMarkStack* _revisitStack;
|
|
|
1311 bool _yield;
|
|
|
1312 int _skipBits;
|
|
|
1313 HeapWord* _finger;
|
|
|
1314 HeapWord* _threshold;
|
|
|
1315 DEBUG_ONLY(bool _verifying;)
|
|
|
1316
|
|
|
1317 public:
|
|
|
1318 MarkFromRootsClosure(CMSCollector* collector, MemRegion span,
|
|
|
1319 CMSBitMap* bitMap,
|
|
|
1320 CMSMarkStack* markStack,
|
|
|
1321 CMSMarkStack* revisitStack,
|
|
|
1322 bool should_yield, bool verifying = false);
|
|
|
1323 void do_bit(size_t offset);
|
|
|
1324 void reset(HeapWord* addr);
|
|
|
1325 inline void do_yield_check();
|
|
|
1326
|
|
|
1327 private:
|
|
|
1328 void scanOopsInOop(HeapWord* ptr);
|
|
|
1329 void do_yield_work();
|
|
|
1330 };
|
|
|
1331
|
|
|
1332 // This closure is used to do concurrent multi-threaded
|
|
|
1333 // marking from the roots following the first checkpoint.
|
|
|
1334 // XXX This should really be a subclass of The serial version
|
|
|
1335 // above, but i have not had the time to refactor things cleanly.
|
|
|
1336 // That willbe done for Dolphin.
|
|
|
1337 class Par_MarkFromRootsClosure: public BitMapClosure {
|
|
|
1338 CMSCollector* _collector;
|
|
|
1339 MemRegion _whole_span;
|
|
|
1340 MemRegion _span;
|
|
|
1341 CMSBitMap* _bit_map;
|
|
|
1342 CMSBitMap* _mut;
|
|
|
1343 OopTaskQueue* _work_queue;
|
|
|
1344 CMSMarkStack* _overflow_stack;
|
|
|
1345 CMSMarkStack* _revisit_stack;
|
|
|
1346 bool _yield;
|
|
|
1347 int _skip_bits;
|
|
|
1348 HeapWord* _finger;
|
|
|
1349 HeapWord* _threshold;
|
|
|
1350 CMSConcMarkingTask* _task;
|
|
|
1351 public:
|
|
|
1352 Par_MarkFromRootsClosure(CMSConcMarkingTask* task, CMSCollector* collector,
|
|
|
1353 MemRegion span,
|
|
|
1354 CMSBitMap* bit_map,
|
|
|
1355 OopTaskQueue* work_queue,
|
|
|
1356 CMSMarkStack* overflow_stack,
|
|
|
1357 CMSMarkStack* revisit_stack,
|
|
|
1358 bool should_yield);
|
|
|
1359 void do_bit(size_t offset);
|
|
|
1360 inline void do_yield_check();
|
|
|
1361
|
|
|
1362 private:
|
|
|
1363 void scan_oops_in_oop(HeapWord* ptr);
|
|
|
1364 void do_yield_work();
|
|
|
1365 bool get_work_from_overflow_stack();
|
|
|
1366 };
|
|
|
1367
|
|
|
1368 // The following closures are used to do certain kinds of verification of
|
|
|
1369 // CMS marking.
|
|
|
1370 class PushAndMarkVerifyClosure: public OopClosure {
|
|
|
1371 CMSCollector* _collector;
|
|
|
1372 MemRegion _span;
|
|
|
1373 CMSBitMap* _verification_bm;
|
|
|
1374 CMSBitMap* _cms_bm;
|
|
|
1375 CMSMarkStack* _mark_stack;
|
|
|
1376 public:
|
|
|
1377 PushAndMarkVerifyClosure(CMSCollector* cms_collector,
|
|
|
1378 MemRegion span,
|
|
|
1379 CMSBitMap* verification_bm,
|
|
|
1380 CMSBitMap* cms_bm,
|
|
|
1381 CMSMarkStack* mark_stack);
|
|
|
1382 void do_oop(oop* p);
|
|
|
1383 // Deal with a stack overflow condition
|
|
|
1384 void handle_stack_overflow(HeapWord* lost);
|
|
|
1385 };
|
|
|
1386
|
|
|
1387 class MarkFromRootsVerifyClosure: public BitMapClosure {
|
|
|
1388 CMSCollector* _collector;
|
|
|
1389 MemRegion _span;
|
|
|
1390 CMSBitMap* _verification_bm;
|
|
|
1391 CMSBitMap* _cms_bm;
|
|
|
1392 CMSMarkStack* _mark_stack;
|
|
|
1393 HeapWord* _finger;
|
|
|
1394 PushAndMarkVerifyClosure _pam_verify_closure;
|
|
|
1395 public:
|
|
|
1396 MarkFromRootsVerifyClosure(CMSCollector* collector, MemRegion span,
|
|
|
1397 CMSBitMap* verification_bm,
|
|
|
1398 CMSBitMap* cms_bm,
|
|
|
1399 CMSMarkStack* mark_stack);
|
|
|
1400 void do_bit(size_t offset);
|
|
|
1401 void reset(HeapWord* addr);
|
|
|
1402 };
|
|
|
1403
|
|
|
1404
|
|
|
1405 // This closure is used to check that a certain set of bits is
|
|
|
1406 // "empty" (i.e. the bit vector doesn't have any 1-bits).
|
|
|
1407 class FalseBitMapClosure: public BitMapClosure {
|
|
|
1408 public:
|
|
|
1409 void do_bit(size_t offset) {
|
|
|
1410 guarantee(false, "Should not have a 1 bit");
|
|
|
1411 }
|
|
|
1412 };
|
|
|
1413
|
|
|
1414 // This closure is used during the second checkpointing phase
|
|
|
1415 // to rescan the marked objects on the dirty cards in the mod
|
|
|
1416 // union table and the card table proper. It's invoked via
|
|
|
1417 // MarkFromDirtyCardsClosure below. It uses either
|
|
|
1418 // [Par_]MarkRefsIntoAndScanClosure (Par_ in the parallel case)
|
|
|
1419 // declared in genOopClosures.hpp to accomplish some of its work.
|
|
|
1420 // In the parallel case the bitMap is shared, so access to
|
|
|
1421 // it needs to be suitably synchronized for updates by embedded
|
|
|
1422 // closures that update it; however, this closure itself only
|
|
|
1423 // reads the bit_map and because it is idempotent, is immune to
|
|
|
1424 // reading stale values.
|
|
|
1425 class ScanMarkedObjectsAgainClosure: public UpwardsObjectClosure {
|
|
|
1426 #ifdef ASSERT
|
|
|
1427 CMSCollector* _collector;
|
|
|
1428 MemRegion _span;
|
|
|
1429 union {
|
|
|
1430 CMSMarkStack* _mark_stack;
|
|
|
1431 OopTaskQueue* _work_queue;
|
|
|
1432 };
|
|
|
1433 #endif // ASSERT
|
|
|
1434 bool _parallel;
|
|
|
1435 CMSBitMap* _bit_map;
|
|
|
1436 union {
|
|
|
1437 MarkRefsIntoAndScanClosure* _scan_closure;
|
|
|
1438 Par_MarkRefsIntoAndScanClosure* _par_scan_closure;
|
|
|
1439 };
|
|
|
1440
|
|
|
1441 public:
|
|
|
1442 ScanMarkedObjectsAgainClosure(CMSCollector* collector,
|
|
|
1443 MemRegion span,
|
|
|
1444 ReferenceProcessor* rp,
|
|
|
1445 CMSBitMap* bit_map,
|
|
|
1446 CMSMarkStack* mark_stack,
|
|
|
1447 CMSMarkStack* revisit_stack,
|
|
|
1448 MarkRefsIntoAndScanClosure* cl):
|
|
|
1449 #ifdef ASSERT
|
|
|
1450 _collector(collector),
|
|
|
1451 _span(span),
|
|
|
1452 _mark_stack(mark_stack),
|
|
|
1453 #endif // ASSERT
|
|
|
1454 _parallel(false),
|
|
|
1455 _bit_map(bit_map),
|
|
|
1456 _scan_closure(cl) { }
|
|
|
1457
|
|
|
1458 ScanMarkedObjectsAgainClosure(CMSCollector* collector,
|
|
|
1459 MemRegion span,
|
|
|
1460 ReferenceProcessor* rp,
|
|
|
1461 CMSBitMap* bit_map,
|
|
|
1462 OopTaskQueue* work_queue,
|
|
|
1463 CMSMarkStack* revisit_stack,
|
|
|
1464 Par_MarkRefsIntoAndScanClosure* cl):
|
|
|
1465 #ifdef ASSERT
|
|
|
1466 _collector(collector),
|
|
|
1467 _span(span),
|
|
|
1468 _work_queue(work_queue),
|
|
|
1469 #endif // ASSERT
|
|
|
1470 _parallel(true),
|
|
|
1471 _bit_map(bit_map),
|
|
|
1472 _par_scan_closure(cl) { }
|
|
|
1473
|
|
|
1474 void do_object(oop obj) {
|
|
|
1475 guarantee(false, "Call do_object_b(oop, MemRegion) instead");
|
|
|
1476 }
|
|
|
1477 bool do_object_b(oop obj) {
|
|
|
1478 guarantee(false, "Call do_object_b(oop, MemRegion) form instead");
|
|
|
1479 return false;
|
|
|
1480 }
|
|
|
1481 bool do_object_bm(oop p, MemRegion mr);
|
|
|
1482 };
|
|
|
1483
|
|
|
1484 // This closure is used during the second checkpointing phase
|
|
|
1485 // to rescan the marked objects on the dirty cards in the mod
|
|
|
1486 // union table and the card table proper. It invokes
|
|
|
1487 // ScanMarkedObjectsAgainClosure above to accomplish much of its work.
|
|
|
1488 // In the parallel case, the bit map is shared and requires
|
|
|
1489 // synchronized access.
|
|
|
1490 class MarkFromDirtyCardsClosure: public MemRegionClosure {
|
|
|
1491 CompactibleFreeListSpace* _space;
|
|
|
1492 ScanMarkedObjectsAgainClosure _scan_cl;
|
|
|
1493 size_t _num_dirty_cards;
|
|
|
1494
|
|
|
1495 public:
|
|
|
1496 MarkFromDirtyCardsClosure(CMSCollector* collector,
|
|
|
1497 MemRegion span,
|
|
|
1498 CompactibleFreeListSpace* space,
|
|
|
1499 CMSBitMap* bit_map,
|
|
|
1500 CMSMarkStack* mark_stack,
|
|
|
1501 CMSMarkStack* revisit_stack,
|
|
|
1502 MarkRefsIntoAndScanClosure* cl):
|
|
|
1503 _space(space),
|
|
|
1504 _num_dirty_cards(0),
|
|
|
1505 _scan_cl(collector, span, collector->ref_processor(), bit_map,
|
|
|
1506 mark_stack, revisit_stack, cl) { }
|
|
|
1507
|
|
|
1508 MarkFromDirtyCardsClosure(CMSCollector* collector,
|
|
|
1509 MemRegion span,
|
|
|
1510 CompactibleFreeListSpace* space,
|
|
|
1511 CMSBitMap* bit_map,
|
|
|
1512 OopTaskQueue* work_queue,
|
|
|
1513 CMSMarkStack* revisit_stack,
|
|
|
1514 Par_MarkRefsIntoAndScanClosure* cl):
|
|
|
1515 _space(space),
|
|
|
1516 _num_dirty_cards(0),
|
|
|
1517 _scan_cl(collector, span, collector->ref_processor(), bit_map,
|
|
|
1518 work_queue, revisit_stack, cl) { }
|
|
|
1519
|
|
|
1520 void do_MemRegion(MemRegion mr);
|
|
|
1521 void set_space(CompactibleFreeListSpace* space) { _space = space; }
|
|
|
1522 size_t num_dirty_cards() { return _num_dirty_cards; }
|
|
|
1523 };
|
|
|
1524
|
|
|
1525 // This closure is used in the non-product build to check
|
|
|
1526 // that there are no MemRegions with a certain property.
|
|
|
1527 class FalseMemRegionClosure: public MemRegionClosure {
|
|
|
1528 void do_MemRegion(MemRegion mr) {
|
|
|
1529 guarantee(!mr.is_empty(), "Shouldn't be empty");
|
|
|
1530 guarantee(false, "Should never be here");
|
|
|
1531 }
|
|
|
1532 };
|
|
|
1533
|
|
|
1534 // This closure is used during the precleaning phase
|
|
|
1535 // to "carefully" rescan marked objects on dirty cards.
|
|
|
1536 // It uses MarkRefsIntoAndScanClosure declared in genOopClosures.hpp
|
|
|
1537 // to accomplish some of its work.
|
|
|
1538 class ScanMarkedObjectsAgainCarefullyClosure: public ObjectClosureCareful {
|
|
|
1539 CMSCollector* _collector;
|
|
|
1540 MemRegion _span;
|
|
|
1541 bool _yield;
|
|
|
1542 Mutex* _freelistLock;
|
|
|
1543 CMSBitMap* _bitMap;
|
|
|
1544 CMSMarkStack* _markStack;
|
|
|
1545 MarkRefsIntoAndScanClosure* _scanningClosure;
|
|
|
1546
|
|
|
1547 public:
|
|
|
1548 ScanMarkedObjectsAgainCarefullyClosure(CMSCollector* collector,
|
|
|
1549 MemRegion span,
|
|
|
1550 CMSBitMap* bitMap,
|
|
|
1551 CMSMarkStack* markStack,
|
|
|
1552 CMSMarkStack* revisitStack,
|
|
|
1553 MarkRefsIntoAndScanClosure* cl,
|
|
|
1554 bool should_yield):
|
|
|
1555 _collector(collector),
|
|
|
1556 _span(span),
|
|
|
1557 _yield(should_yield),
|
|
|
1558 _bitMap(bitMap),
|
|
|
1559 _markStack(markStack),
|
|
|
1560 _scanningClosure(cl) {
|
|
|
1561 }
|
|
|
1562
|
|
|
1563 void do_object(oop p) {
|
|
|
1564 guarantee(false, "call do_object_careful instead");
|
|
|
1565 }
|
|
|
1566
|
|
|
1567 size_t do_object_careful(oop p) {
|
|
|
1568 guarantee(false, "Unexpected caller");
|
|
|
1569 return 0;
|
|
|
1570 }
|
|
|
1571
|
|
|
1572 size_t do_object_careful_m(oop p, MemRegion mr);
|
|
|
1573
|
|
|
1574 void setFreelistLock(Mutex* m) {
|
|
|
1575 _freelistLock = m;
|
|
|
1576 _scanningClosure->set_freelistLock(m);
|
|
|
1577 }
|
|
|
1578
|
|
|
1579 private:
|
|
|
1580 inline bool do_yield_check();
|
|
|
1581
|
|
|
1582 void do_yield_work();
|
|
|
1583 };
|
|
|
1584
|
|
|
1585 class SurvivorSpacePrecleanClosure: public ObjectClosureCareful {
|
|
|
1586 CMSCollector* _collector;
|
|
|
1587 MemRegion _span;
|
|
|
1588 bool _yield;
|
|
|
1589 CMSBitMap* _bit_map;
|
|
|
1590 CMSMarkStack* _mark_stack;
|
|
|
1591 PushAndMarkClosure* _scanning_closure;
|
|
|
1592 unsigned int _before_count;
|
|
|
1593
|
|
|
1594 public:
|
|
|
1595 SurvivorSpacePrecleanClosure(CMSCollector* collector,
|
|
|
1596 MemRegion span,
|
|
|
1597 CMSBitMap* bit_map,
|
|
|
1598 CMSMarkStack* mark_stack,
|
|
|
1599 PushAndMarkClosure* cl,
|
|
|
1600 unsigned int before_count,
|
|
|
1601 bool should_yield):
|
|
|
1602 _collector(collector),
|
|
|
1603 _span(span),
|
|
|
1604 _yield(should_yield),
|
|
|
1605 _bit_map(bit_map),
|
|
|
1606 _mark_stack(mark_stack),
|
|
|
1607 _scanning_closure(cl),
|
|
|
1608 _before_count(before_count)
|
|
|
1609 { }
|
|
|
1610
|
|
|
1611 void do_object(oop p) {
|
|
|
1612 guarantee(false, "call do_object_careful instead");
|
|
|
1613 }
|
|
|
1614
|
|
|
1615 size_t do_object_careful(oop p);
|
|
|
1616
|
|
|
1617 size_t do_object_careful_m(oop p, MemRegion mr) {
|
|
|
1618 guarantee(false, "Unexpected caller");
|
|
|
1619 return 0;
|
|
|
1620 }
|
|
|
1621
|
|
|
1622 private:
|
|
|
1623 inline void do_yield_check();
|
|
|
1624 void do_yield_work();
|
|
|
1625 };
|
|
|
1626
|
|
|
1627 // This closure is used to accomplish the sweeping work
|
|
|
1628 // after the second checkpoint but before the concurrent reset
|
|
|
1629 // phase.
|
|
|
1630 //
|
|
|
1631 // Terminology
|
|
|
1632 // left hand chunk (LHC) - block of one or more chunks currently being
|
|
|
1633 // coalesced. The LHC is available for coalescing with a new chunk.
|
|
|
1634 // right hand chunk (RHC) - block that is currently being swept that is
|
|
|
1635 // free or garbage that can be coalesced with the LHC.
|
|
|
1636 // _inFreeRange is true if there is currently a LHC
|
|
|
1637 // _lastFreeRangeCoalesced is true if the LHC consists of more than one chunk.
|
|
|
1638 // _freeRangeInFreeLists is true if the LHC is in the free lists.
|
|
|
1639 // _freeFinger is the address of the current LHC
|
|
|
1640 class SweepClosure: public BlkClosureCareful {
|
|
|
1641 CMSCollector* _collector; // collector doing the work
|
|
|
1642 ConcurrentMarkSweepGeneration* _g; // Generation being swept
|
|
|
1643 CompactibleFreeListSpace* _sp; // Space being swept
|
|
|
1644 HeapWord* _limit;
|
|
|
1645 Mutex* _freelistLock; // Free list lock (in space)
|
|
|
1646 CMSBitMap* _bitMap; // Marking bit map (in
|
|
|
1647 // generation)
|
|
|
1648 bool _inFreeRange; // Indicates if we are in the
|
|
|
1649 // midst of a free run
|
|
|
1650 bool _freeRangeInFreeLists;
|
|
|
1651 // Often, we have just found
|
|
|
1652 // a free chunk and started
|
|
|
1653 // a new free range; we do not
|
|
|
1654 // eagerly remove this chunk from
|
|
|
1655 // the free lists unless there is
|
|
|
1656 // a possibility of coalescing.
|
|
|
1657 // When true, this flag indicates
|
|
|
1658 // that the _freeFinger below
|
|
|
1659 // points to a potentially free chunk
|
|
|
1660 // that may still be in the free lists
|
|
|
1661 bool _lastFreeRangeCoalesced;
|
|
|
1662 // free range contains chunks
|
|
|
1663 // coalesced
|
|
|
1664 bool _yield;
|
|
|
1665 // Whether sweeping should be
|
|
|
1666 // done with yields. For instance
|
|
|
1667 // when done by the foreground
|
|
|
1668 // collector we shouldn't yield.
|
|
|
1669 HeapWord* _freeFinger; // When _inFreeRange is set, the
|
|
|
1670 // pointer to the "left hand
|
|
|
1671 // chunk"
|
|
|
1672 size_t _freeRangeSize;
|
|
|
1673 // When _inFreeRange is set, this
|
|
|
1674 // indicates the accumulated size
|
|
|
1675 // of the "left hand chunk"
|
|
|
1676 NOT_PRODUCT(
|
|
|
1677 size_t _numObjectsFreed;
|
|
|
1678 size_t _numWordsFreed;
|
|
|
1679 size_t _numObjectsLive;
|
|
|
1680 size_t _numWordsLive;
|
|
|
1681 size_t _numObjectsAlreadyFree;
|
|
|
1682 size_t _numWordsAlreadyFree;
|
|
|
1683 FreeChunk* _last_fc;
|
|
|
1684 )
|
|
|
1685 private:
|
|
|
1686 // Code that is common to a free chunk or garbage when
|
|
|
1687 // encountered during sweeping.
|
|
|
1688 void doPostIsFreeOrGarbageChunk(FreeChunk *fc,
|
|
|
1689 size_t chunkSize);
|
|
|
1690 // Process a free chunk during sweeping.
|
|
|
1691 void doAlreadyFreeChunk(FreeChunk *fc);
|
|
|
1692 // Process a garbage chunk during sweeping.
|
|
|
1693 size_t doGarbageChunk(FreeChunk *fc);
|
|
|
1694 // Process a live chunk during sweeping.
|
|
|
1695 size_t doLiveChunk(FreeChunk* fc);
|
|
|
1696
|
|
|
1697 // Accessors.
|
|
|
1698 HeapWord* freeFinger() const { return _freeFinger; }
|
|
|
1699 void set_freeFinger(HeapWord* v) { _freeFinger = v; }
|
|
|
1700 size_t freeRangeSize() const { return _freeRangeSize; }
|
|
|
1701 void set_freeRangeSize(size_t v) { _freeRangeSize = v; }
|
|
|
1702 bool inFreeRange() const { return _inFreeRange; }
|
|
|
1703 void set_inFreeRange(bool v) { _inFreeRange = v; }
|
|
|
1704 bool lastFreeRangeCoalesced() const { return _lastFreeRangeCoalesced; }
|
|
|
1705 void set_lastFreeRangeCoalesced(bool v) { _lastFreeRangeCoalesced = v; }
|
|
|
1706 bool freeRangeInFreeLists() const { return _freeRangeInFreeLists; }
|
|
|
1707 void set_freeRangeInFreeLists(bool v) { _freeRangeInFreeLists = v; }
|
|
|
1708
|
|
|
1709 // Initialize a free range.
|
|
|
1710 void initialize_free_range(HeapWord* freeFinger, bool freeRangeInFreeLists);
|
|
|
1711 // Return this chunk to the free lists.
|
|
|
1712 void flushCurFreeChunk(HeapWord* chunk, size_t size);
|
|
|
1713
|
|
|
1714 // Check if we should yield and do so when necessary.
|
|
|
1715 inline void do_yield_check(HeapWord* addr);
|
|
|
1716
|
|
|
1717 // Yield
|
|
|
1718 void do_yield_work(HeapWord* addr);
|
|
|
1719
|
|
|
1720 // Debugging/Printing
|
|
|
1721 void record_free_block_coalesced(FreeChunk* fc) const PRODUCT_RETURN;
|
|
|
1722
|
|
|
1723 public:
|
|
|
1724 SweepClosure(CMSCollector* collector, ConcurrentMarkSweepGeneration* g,
|
|
|
1725 CMSBitMap* bitMap, bool should_yield);
|
|
|
1726 ~SweepClosure();
|
|
|
1727
|
|
|
1728 size_t do_blk_careful(HeapWord* addr);
|
|
|
1729 };
|
|
|
1730
|
|
|
1731 // Closures related to weak references processing
|
|
|
1732
|
|
|
1733 // During CMS' weak reference processing, this is a
|
|
|
1734 // work-routine/closure used to complete transitive
|
|
|
1735 // marking of objects as live after a certain point
|
|
|
1736 // in which an initial set has been completely accumulated.
|
|
|
1737 class CMSDrainMarkingStackClosure: public VoidClosure {
|
|
|
1738 CMSCollector* _collector;
|
|
|
1739 MemRegion _span;
|
|
|
1740 CMSMarkStack* _mark_stack;
|
|
|
1741 CMSBitMap* _bit_map;
|
|
|
1742 CMSKeepAliveClosure* _keep_alive;
|
|
|
1743 public:
|
|
|
1744 CMSDrainMarkingStackClosure(CMSCollector* collector, MemRegion span,
|
|
|
1745 CMSBitMap* bit_map, CMSMarkStack* mark_stack,
|
|
|
1746 CMSKeepAliveClosure* keep_alive):
|
|
|
1747 _collector(collector),
|
|
|
1748 _span(span),
|
|
|
1749 _bit_map(bit_map),
|
|
|
1750 _mark_stack(mark_stack),
|
|
|
1751 _keep_alive(keep_alive) { }
|
|
|
1752
|
|
|
1753 void do_void();
|
|
|
1754 };
|
|
|
1755
|
|
|
1756 // A parallel version of CMSDrainMarkingStackClosure above.
|
|
|
1757 class CMSParDrainMarkingStackClosure: public VoidClosure {
|
|
|
1758 CMSCollector* _collector;
|
|
|
1759 MemRegion _span;
|
|
|
1760 OopTaskQueue* _work_queue;
|
|
|
1761 CMSBitMap* _bit_map;
|
|
|
1762 CMSInnerParMarkAndPushClosure _mark_and_push;
|
|
|
1763
|
|
|
1764 public:
|
|
|
1765 CMSParDrainMarkingStackClosure(CMSCollector* collector,
|
|
|
1766 MemRegion span, CMSBitMap* bit_map,
|
|
|
1767 OopTaskQueue* work_queue):
|
|
|
1768 _collector(collector),
|
|
|
1769 _span(span),
|
|
|
1770 _bit_map(bit_map),
|
|
|
1771 _work_queue(work_queue),
|
|
|
1772 _mark_and_push(collector, span, bit_map, work_queue) { }
|
|
|
1773
|
|
|
1774 public:
|
|
|
1775 void trim_queue(uint max);
|
|
|
1776 void do_void();
|
|
|
1777 };
|
|
|
1778
|
|
|
1779 // Allow yielding or short-circuiting of reference list
|
|
|
1780 // prelceaning work.
|
|
|
1781 class CMSPrecleanRefsYieldClosure: public YieldClosure {
|
|
|
1782 CMSCollector* _collector;
|
|
|
1783 void do_yield_work();
|
|
|
1784 public:
|
|
|
1785 CMSPrecleanRefsYieldClosure(CMSCollector* collector):
|
|
|
1786 _collector(collector) {}
|
|
|
1787 virtual bool should_return();
|
|
|
1788 };
|
|
|
1789
|
|
|
1790
|
|
|
1791 // Convenience class that locks free list locks for given CMS collector
|
|
|
1792 class FreelistLocker: public StackObj {
|
|
|
1793 private:
|
|
|
1794 CMSCollector* _collector;
|
|
|
1795 public:
|
|
|
1796 FreelistLocker(CMSCollector* collector):
|
|
|
1797 _collector(collector) {
|
|
|
1798 _collector->getFreelistLocks();
|
|
|
1799 }
|
|
|
1800
|
|
|
1801 ~FreelistLocker() {
|
|
|
1802 _collector->releaseFreelistLocks();
|
|
|
1803 }
|
|
|
1804 };
|
|
|
1805
|
|
|
1806 // Mark all dead objects in a given space.
|
|
|
1807 class MarkDeadObjectsClosure: public BlkClosure {
|
|
|
1808 const CMSCollector* _collector;
|
|
|
1809 const CompactibleFreeListSpace* _sp;
|
|
|
1810 CMSBitMap* _live_bit_map;
|
|
|
1811 CMSBitMap* _dead_bit_map;
|
|
|
1812 public:
|
|
|
1813 MarkDeadObjectsClosure(const CMSCollector* collector,
|
|
|
1814 const CompactibleFreeListSpace* sp,
|
|
|
1815 CMSBitMap *live_bit_map,
|
|
|
1816 CMSBitMap *dead_bit_map) :
|
|
|
1817 _collector(collector),
|
|
|
1818 _sp(sp),
|
|
|
1819 _live_bit_map(live_bit_map),
|
|
|
1820 _dead_bit_map(dead_bit_map) {}
|
|
|
1821 size_t do_blk(HeapWord* addr);
|
|
|
1822 };
|
