Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/concurrentMarkSweep/promotionInfo.hpp @ 1644:2a47bd84841f
6965184: possible races in make_not_entrant_or_zombie
Reviewed-by: kvn
| author | never |
|---|---|
| date | Thu, 08 Jul 2010 14:29:44 -0700 |
| parents | c18cbe5936b8 |
| children | f95d63e2154a |
| rev | line source |
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| 1521 | 1 /* |
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2 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved. |
| 1521 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 1521 | 22 * |
| 23 */ | |
| 24 | |
| 25 // Forward declarations | |
| 26 class CompactibleFreeListSpace; | |
| 27 | |
| 28 class PromotedObject VALUE_OBJ_CLASS_SPEC { | |
| 29 private: | |
| 30 enum { | |
| 31 promoted_mask = right_n_bits(2), // i.e. 0x3 | |
| 32 displaced_mark = nth_bit(2), // i.e. 0x4 | |
| 33 next_mask = ~(right_n_bits(3)) // i.e. ~(0x7) | |
| 34 }; | |
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35 |
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36 // Below, we want _narrow_next in the "higher" 32 bit slot, |
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37 // whose position will depend on endian-ness of the platform. |
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38 // This is so that there is no interference with the |
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39 // cms_free_bit occupying bit position 7 (lsb == 0) |
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40 // when we are using compressed oops; see FreeChunk::isFree(). |
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41 // We cannot move the cms_free_bit down because currently |
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42 // biased locking code assumes that age bits are contiguous |
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43 // with the lock bits. Even if that assumption were relaxed, |
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44 // the least position we could move this bit to would be |
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45 // to bit position 3, which would require 16 byte alignment. |
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46 typedef struct { |
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47 #ifdef VM_LITTLE_ENDIAN |
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48 LP64_ONLY(narrowOop _pad;) |
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49 narrowOop _narrow_next; |
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50 #else |
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51 narrowOop _narrow_next; |
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52 LP64_ONLY(narrowOop _pad;) |
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53 #endif |
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54 } Data; |
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55 |
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56 union { |
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57 intptr_t _next; |
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58 Data _data; |
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59 }; |
| 1521 | 60 public: |
| 61 inline PromotedObject* next() const { | |
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62 assert(!((FreeChunk*)this)->isFree(), "Error"); |
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63 PromotedObject* res; |
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64 if (UseCompressedOops) { |
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65 // The next pointer is a compressed oop stored in the top 32 bits |
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66 res = (PromotedObject*)oopDesc::decode_heap_oop(_data._narrow_next); |
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67 } else { |
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68 res = (PromotedObject*)(_next & next_mask); |
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69 } |
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70 assert(oop(res)->is_oop_or_null(true /* ignore mark word */), "Not an oop?"); |
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71 return res; |
| 1521 | 72 } |
| 73 inline void setNext(PromotedObject* x) { | |
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74 assert(((intptr_t)x & ~next_mask) == 0, "Conflict in bit usage, " |
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75 "or insufficient alignment of objects"); |
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76 if (UseCompressedOops) { |
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77 assert(_data._narrow_next == 0, "Overwrite?"); |
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78 _data._narrow_next = oopDesc::encode_heap_oop(oop(x)); |
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79 } else { |
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80 _next |= (intptr_t)x; |
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81 } |
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82 assert(!((FreeChunk*)this)->isFree(), "Error"); |
| 1521 | 83 } |
| 84 inline void setPromotedMark() { | |
| 85 _next |= promoted_mask; | |
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86 assert(!((FreeChunk*)this)->isFree(), "Error"); |
| 1521 | 87 } |
| 88 inline bool hasPromotedMark() const { | |
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89 assert(!((FreeChunk*)this)->isFree(), "Error"); |
| 1521 | 90 return (_next & promoted_mask) == promoted_mask; |
| 91 } | |
| 92 inline void setDisplacedMark() { | |
| 93 _next |= displaced_mark; | |
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94 assert(!((FreeChunk*)this)->isFree(), "Error"); |
| 1521 | 95 } |
| 96 inline bool hasDisplacedMark() const { | |
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97 assert(!((FreeChunk*)this)->isFree(), "Error"); |
| 1521 | 98 return (_next & displaced_mark) != 0; |
| 99 } | |
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100 inline void clearNext() { |
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101 _next = 0; |
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102 assert(!((FreeChunk*)this)->isFree(), "Error"); |
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103 } |
| 1521 | 104 debug_only(void *next_addr() { return (void *) &_next; }) |
| 105 }; | |
| 106 | |
| 107 class SpoolBlock: public FreeChunk { | |
| 108 friend class PromotionInfo; | |
| 109 protected: | |
| 110 SpoolBlock* nextSpoolBlock; | |
| 111 size_t bufferSize; // number of usable words in this block | |
| 112 markOop* displacedHdr; // the displaced headers start here | |
| 113 | |
| 114 // Note about bufferSize: it denotes the number of entries available plus 1; | |
| 115 // legal indices range from 1 through BufferSize - 1. See the verification | |
| 116 // code verify() that counts the number of displaced headers spooled. | |
| 117 size_t computeBufferSize() { | |
| 118 return (size() * sizeof(HeapWord) - sizeof(*this)) / sizeof(markOop); | |
| 119 } | |
| 120 | |
| 121 public: | |
| 122 void init() { | |
| 123 bufferSize = computeBufferSize(); | |
| 124 displacedHdr = (markOop*)&displacedHdr; | |
| 125 nextSpoolBlock = NULL; | |
| 126 } | |
| 127 | |
| 128 void print_on(outputStream* st) const; | |
| 129 void print() const { print_on(gclog_or_tty); } | |
| 130 }; | |
| 131 | |
| 132 class PromotionInfo VALUE_OBJ_CLASS_SPEC { | |
| 133 bool _tracking; // set if tracking | |
| 134 CompactibleFreeListSpace* _space; // the space to which this belongs | |
| 135 PromotedObject* _promoHead; // head of list of promoted objects | |
| 136 PromotedObject* _promoTail; // tail of list of promoted objects | |
| 137 SpoolBlock* _spoolHead; // first spooling block | |
| 138 SpoolBlock* _spoolTail; // last non-full spooling block or null | |
| 139 SpoolBlock* _splice_point; // when _spoolTail is null, holds list tail | |
| 140 SpoolBlock* _spareSpool; // free spool buffer | |
| 141 size_t _firstIndex; // first active index in | |
| 142 // first spooling block (_spoolHead) | |
| 143 size_t _nextIndex; // last active index + 1 in last | |
| 144 // spooling block (_spoolTail) | |
| 145 private: | |
| 146 // ensure that spooling space exists; return true if there is spooling space | |
| 147 bool ensure_spooling_space_work(); | |
| 148 | |
| 149 public: | |
| 150 PromotionInfo() : | |
| 151 _tracking(0), _space(NULL), | |
| 152 _promoHead(NULL), _promoTail(NULL), | |
| 153 _spoolHead(NULL), _spoolTail(NULL), | |
| 154 _spareSpool(NULL), _firstIndex(1), | |
| 155 _nextIndex(1) {} | |
| 156 | |
| 157 bool noPromotions() const { | |
| 158 assert(_promoHead != NULL || _promoTail == NULL, "list inconsistency"); | |
| 159 return _promoHead == NULL; | |
| 160 } | |
| 161 void startTrackingPromotions(); | |
| 162 void stopTrackingPromotions(uint worker_id = 0); | |
| 163 bool tracking() const { return _tracking; } | |
| 164 void track(PromotedObject* trackOop); // keep track of a promoted oop | |
| 165 // The following variant must be used when trackOop is not fully | |
| 166 // initialized and has a NULL klass: | |
| 167 void track(PromotedObject* trackOop, klassOop klassOfOop); // keep track of a promoted oop | |
| 168 void setSpace(CompactibleFreeListSpace* sp) { _space = sp; } | |
| 169 CompactibleFreeListSpace* space() const { return _space; } | |
| 170 markOop nextDisplacedHeader(); // get next header & forward spool pointer | |
| 171 void saveDisplacedHeader(markOop hdr); | |
| 172 // save header and forward spool | |
| 173 | |
| 174 inline size_t refillSize() const; | |
| 175 | |
| 176 SpoolBlock* getSpoolBlock(); // return a free spooling block | |
| 177 inline bool has_spooling_space() { | |
| 178 return _spoolTail != NULL && _spoolTail->bufferSize > _nextIndex; | |
| 179 } | |
| 180 // ensure that spooling space exists | |
| 181 bool ensure_spooling_space() { | |
| 182 return has_spooling_space() || ensure_spooling_space_work(); | |
| 183 } | |
| 184 #define PROMOTED_OOPS_ITERATE_DECL(OopClosureType, nv_suffix) \ | |
| 185 void promoted_oops_iterate##nv_suffix(OopClosureType* cl); | |
| 186 ALL_SINCE_SAVE_MARKS_CLOSURES(PROMOTED_OOPS_ITERATE_DECL) | |
| 187 #undef PROMOTED_OOPS_ITERATE_DECL | |
| 188 void promoted_oops_iterate(OopsInGenClosure* cl) { | |
| 189 promoted_oops_iterate_v(cl); | |
| 190 } | |
| 191 void verify() const; | |
| 192 void reset() { | |
| 193 _promoHead = NULL; | |
| 194 _promoTail = NULL; | |
| 195 _spoolHead = NULL; | |
| 196 _spoolTail = NULL; | |
| 197 _spareSpool = NULL; | |
| 198 _firstIndex = 0; | |
| 199 _nextIndex = 0; | |
| 200 | |
| 201 } | |
| 202 | |
| 203 void print_on(outputStream* st) const; | |
| 204 void print_statistics(uint worker_id) const; | |
| 205 }; | |
| 206 |