Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/g1/concurrentMark.hpp @ 1886:72a161e62cc4
6991377: G1: race between concurrent refinement and humongous object allocation
Summary: There is a race between the concurrent refinement threads and the humongous object allocation that can cause the concurrent refinement threads to corrupt the part of the BOT that it is being initialized by the humongous object allocation operation. The solution is to do the humongous object allocation in careful steps to ensure that the concurrent refinement threads always have a consistent view over the BOT, region contents, and top. The fix includes some very minor tidying up in sparsePRT.
Reviewed-by: jcoomes, johnc, ysr
| author | tonyp |
|---|---|
| date | Sat, 16 Oct 2010 17:12:19 -0400 |
| parents | 4805b9f4779e |
| children | f95d63e2154a |
| rev | line source |
|---|---|
| 342 | 1 /* |
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2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved. |
| 342 | 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. |
| 342 | 22 * |
| 23 */ | |
| 24 | |
| 25 class G1CollectedHeap; | |
| 26 class CMTask; | |
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27 typedef GenericTaskQueue<oop> CMTaskQueue; |
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28 typedef GenericTaskQueueSet<CMTaskQueue> CMTaskQueueSet; |
| 342 | 29 |
| 30 // A generic CM bit map. This is essentially a wrapper around the BitMap | |
| 31 // class, with one bit per (1<<_shifter) HeapWords. | |
| 32 | |
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33 class CMBitMapRO VALUE_OBJ_CLASS_SPEC { |
| 342 | 34 protected: |
| 35 HeapWord* _bmStartWord; // base address of range covered by map | |
| 36 size_t _bmWordSize; // map size (in #HeapWords covered) | |
| 37 const int _shifter; // map to char or bit | |
| 38 VirtualSpace _virtual_space; // underlying the bit map | |
| 39 BitMap _bm; // the bit map itself | |
| 40 | |
| 41 public: | |
| 42 // constructor | |
| 43 CMBitMapRO(ReservedSpace rs, int shifter); | |
| 44 | |
| 45 enum { do_yield = true }; | |
| 46 | |
| 47 // inquiries | |
| 48 HeapWord* startWord() const { return _bmStartWord; } | |
| 49 size_t sizeInWords() const { return _bmWordSize; } | |
| 50 // the following is one past the last word in space | |
| 51 HeapWord* endWord() const { return _bmStartWord + _bmWordSize; } | |
| 52 | |
| 53 // read marks | |
| 54 | |
| 55 bool isMarked(HeapWord* addr) const { | |
| 56 assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize), | |
| 57 "outside underlying space?"); | |
| 58 return _bm.at(heapWordToOffset(addr)); | |
| 59 } | |
| 60 | |
| 61 // iteration | |
| 62 bool iterate(BitMapClosure* cl) { return _bm.iterate(cl); } | |
| 63 bool iterate(BitMapClosure* cl, MemRegion mr); | |
| 64 | |
| 65 // Return the address corresponding to the next marked bit at or after | |
| 66 // "addr", and before "limit", if "limit" is non-NULL. If there is no | |
| 67 // such bit, returns "limit" if that is non-NULL, or else "endWord()". | |
| 68 HeapWord* getNextMarkedWordAddress(HeapWord* addr, | |
| 69 HeapWord* limit = NULL) const; | |
| 70 // Return the address corresponding to the next unmarked bit at or after | |
| 71 // "addr", and before "limit", if "limit" is non-NULL. If there is no | |
| 72 // such bit, returns "limit" if that is non-NULL, or else "endWord()". | |
| 73 HeapWord* getNextUnmarkedWordAddress(HeapWord* addr, | |
| 74 HeapWord* limit = NULL) const; | |
| 75 | |
| 76 // conversion utilities | |
| 77 // XXX Fix these so that offsets are size_t's... | |
| 78 HeapWord* offsetToHeapWord(size_t offset) const { | |
| 79 return _bmStartWord + (offset << _shifter); | |
| 80 } | |
| 81 size_t heapWordToOffset(HeapWord* addr) const { | |
| 82 return pointer_delta(addr, _bmStartWord) >> _shifter; | |
| 83 } | |
| 84 int heapWordDiffToOffsetDiff(size_t diff) const; | |
| 85 HeapWord* nextWord(HeapWord* addr) { | |
| 86 return offsetToHeapWord(heapWordToOffset(addr) + 1); | |
| 87 } | |
| 88 | |
| 89 void mostly_disjoint_range_union(BitMap* from_bitmap, | |
| 90 size_t from_start_index, | |
| 91 HeapWord* to_start_word, | |
| 92 size_t word_num); | |
| 93 | |
| 94 // debugging | |
| 95 NOT_PRODUCT(bool covers(ReservedSpace rs) const;) | |
| 96 }; | |
| 97 | |
| 98 class CMBitMap : public CMBitMapRO { | |
| 99 | |
| 100 public: | |
| 101 // constructor | |
| 102 CMBitMap(ReservedSpace rs, int shifter) : | |
| 103 CMBitMapRO(rs, shifter) {} | |
| 104 | |
| 105 // write marks | |
| 106 void mark(HeapWord* addr) { | |
| 107 assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize), | |
| 108 "outside underlying space?"); | |
| 109 _bm.at_put(heapWordToOffset(addr), true); | |
| 110 } | |
| 111 void clear(HeapWord* addr) { | |
| 112 assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize), | |
| 113 "outside underlying space?"); | |
| 114 _bm.at_put(heapWordToOffset(addr), false); | |
| 115 } | |
| 116 bool parMark(HeapWord* addr) { | |
| 117 assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize), | |
| 118 "outside underlying space?"); | |
| 119 return _bm.par_at_put(heapWordToOffset(addr), true); | |
| 120 } | |
| 121 bool parClear(HeapWord* addr) { | |
| 122 assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize), | |
| 123 "outside underlying space?"); | |
| 124 return _bm.par_at_put(heapWordToOffset(addr), false); | |
| 125 } | |
| 126 void markRange(MemRegion mr); | |
| 127 void clearAll(); | |
| 128 void clearRange(MemRegion mr); | |
| 129 | |
| 130 // Starting at the bit corresponding to "addr" (inclusive), find the next | |
| 131 // "1" bit, if any. This bit starts some run of consecutive "1"'s; find | |
| 132 // the end of this run (stopping at "end_addr"). Return the MemRegion | |
| 133 // covering from the start of the region corresponding to the first bit | |
| 134 // of the run to the end of the region corresponding to the last bit of | |
| 135 // the run. If there is no "1" bit at or after "addr", return an empty | |
| 136 // MemRegion. | |
| 137 MemRegion getAndClearMarkedRegion(HeapWord* addr, HeapWord* end_addr); | |
| 138 }; | |
| 139 | |
| 140 // Represents a marking stack used by the CM collector. | |
| 141 // Ideally this should be GrowableArray<> just like MSC's marking stack(s). | |
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142 class CMMarkStack VALUE_OBJ_CLASS_SPEC { |
| 342 | 143 ConcurrentMark* _cm; |
| 144 oop* _base; // bottom of stack | |
| 145 jint _index; // one more than last occupied index | |
| 146 jint _capacity; // max #elements | |
| 147 jint _oops_do_bound; // Number of elements to include in next iteration. | |
| 148 NOT_PRODUCT(jint _max_depth;) // max depth plumbed during run | |
| 149 | |
| 150 bool _overflow; | |
| 151 DEBUG_ONLY(bool _drain_in_progress;) | |
| 152 DEBUG_ONLY(bool _drain_in_progress_yields;) | |
| 153 | |
| 154 public: | |
| 155 CMMarkStack(ConcurrentMark* cm); | |
| 156 ~CMMarkStack(); | |
| 157 | |
| 158 void allocate(size_t size); | |
| 159 | |
| 160 oop pop() { | |
| 161 if (!isEmpty()) { | |
| 162 return _base[--_index] ; | |
| 163 } | |
| 164 return NULL; | |
| 165 } | |
| 166 | |
| 167 // If overflow happens, don't do the push, and record the overflow. | |
| 168 // *Requires* that "ptr" is already marked. | |
| 169 void push(oop ptr) { | |
| 170 if (isFull()) { | |
| 171 // Record overflow. | |
| 172 _overflow = true; | |
| 173 return; | |
| 174 } else { | |
| 175 _base[_index++] = ptr; | |
| 176 NOT_PRODUCT(_max_depth = MAX2(_max_depth, _index)); | |
| 177 } | |
| 178 } | |
| 179 // Non-block impl. Note: concurrency is allowed only with other | |
| 180 // "par_push" operations, not with "pop" or "drain". We would need | |
| 181 // parallel versions of them if such concurrency was desired. | |
| 182 void par_push(oop ptr); | |
| 183 | |
| 184 // Pushes the first "n" elements of "ptr_arr" on the stack. | |
| 185 // Non-block impl. Note: concurrency is allowed only with other | |
| 186 // "par_adjoin_arr" or "push" operations, not with "pop" or "drain". | |
| 187 void par_adjoin_arr(oop* ptr_arr, int n); | |
| 188 | |
| 189 // Pushes the first "n" elements of "ptr_arr" on the stack. | |
| 190 // Locking impl: concurrency is allowed only with | |
| 191 // "par_push_arr" and/or "par_pop_arr" operations, which use the same | |
| 192 // locking strategy. | |
| 193 void par_push_arr(oop* ptr_arr, int n); | |
| 194 | |
| 195 // If returns false, the array was empty. Otherwise, removes up to "max" | |
| 196 // elements from the stack, and transfers them to "ptr_arr" in an | |
| 197 // unspecified order. The actual number transferred is given in "n" ("n | |
| 198 // == 0" is deliberately redundant with the return value.) Locking impl: | |
| 199 // concurrency is allowed only with "par_push_arr" and/or "par_pop_arr" | |
| 200 // operations, which use the same locking strategy. | |
| 201 bool par_pop_arr(oop* ptr_arr, int max, int* n); | |
| 202 | |
| 203 // Drain the mark stack, applying the given closure to all fields of | |
| 204 // objects on the stack. (That is, continue until the stack is empty, | |
| 205 // even if closure applications add entries to the stack.) The "bm" | |
| 206 // argument, if non-null, may be used to verify that only marked objects | |
| 207 // are on the mark stack. If "yield_after" is "true", then the | |
| 208 // concurrent marker performing the drain offers to yield after | |
| 209 // processing each object. If a yield occurs, stops the drain operation | |
| 210 // and returns false. Otherwise, returns true. | |
| 211 template<class OopClosureClass> | |
| 212 bool drain(OopClosureClass* cl, CMBitMap* bm, bool yield_after = false); | |
| 213 | |
| 214 bool isEmpty() { return _index == 0; } | |
| 215 bool isFull() { return _index == _capacity; } | |
| 216 int maxElems() { return _capacity; } | |
| 217 | |
| 218 bool overflow() { return _overflow; } | |
| 219 void clear_overflow() { _overflow = false; } | |
| 220 | |
| 221 int size() { return _index; } | |
| 222 | |
| 223 void setEmpty() { _index = 0; clear_overflow(); } | |
| 224 | |
| 225 // Record the current size; a subsequent "oops_do" will iterate only over | |
| 226 // indices valid at the time of this call. | |
| 227 void set_oops_do_bound(jint bound = -1) { | |
| 228 if (bound == -1) { | |
| 229 _oops_do_bound = _index; | |
| 230 } else { | |
| 231 _oops_do_bound = bound; | |
| 232 } | |
| 233 } | |
| 234 jint oops_do_bound() { return _oops_do_bound; } | |
| 235 // iterate over the oops in the mark stack, up to the bound recorded via | |
| 236 // the call above. | |
| 237 void oops_do(OopClosure* f); | |
| 238 }; | |
| 239 | |
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240 class CMRegionStack VALUE_OBJ_CLASS_SPEC { |
| 342 | 241 MemRegion* _base; |
| 242 jint _capacity; | |
| 243 jint _index; | |
| 244 jint _oops_do_bound; | |
| 245 bool _overflow; | |
| 246 public: | |
| 247 CMRegionStack(); | |
| 248 ~CMRegionStack(); | |
| 249 void allocate(size_t size); | |
| 250 | |
| 251 // This is lock-free; assumes that it will only be called in parallel | |
| 252 // with other "push" operations (no pops). | |
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253 void push_lock_free(MemRegion mr); |
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254 |
| 342 | 255 // Lock-free; assumes that it will only be called in parallel |
| 256 // with other "pop" operations (no pushes). | |
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257 MemRegion pop_lock_free(); |
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258 |
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259 #if 0 |
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260 // The routines that manipulate the region stack with a lock are |
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261 // not currently used. They should be retained, however, as a |
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262 // diagnostic aid. |
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263 |
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264 // These two are the implementations that use a lock. They can be |
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265 // called concurrently with each other but they should not be called |
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266 // concurrently with the lock-free versions (push() / pop()). |
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267 void push_with_lock(MemRegion mr); |
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268 MemRegion pop_with_lock(); |
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269 #endif |
| 342 | 270 |
| 271 bool isEmpty() { return _index == 0; } | |
| 272 bool isFull() { return _index == _capacity; } | |
| 273 | |
| 274 bool overflow() { return _overflow; } | |
| 275 void clear_overflow() { _overflow = false; } | |
| 276 | |
| 277 int size() { return _index; } | |
| 278 | |
| 279 // It iterates over the entries in the region stack and it | |
| 280 // invalidates (i.e. assigns MemRegion()) the ones that point to | |
| 281 // regions in the collection set. | |
| 282 bool invalidate_entries_into_cset(); | |
| 283 | |
| 284 // This gives an upper bound up to which the iteration in | |
| 285 // invalidate_entries_into_cset() will reach. This prevents | |
| 286 // newly-added entries to be unnecessarily scanned. | |
| 287 void set_oops_do_bound() { | |
| 288 _oops_do_bound = _index; | |
| 289 } | |
| 290 | |
| 291 void setEmpty() { _index = 0; clear_overflow(); } | |
| 292 }; | |
| 293 | |
| 294 // this will enable a variety of different statistics per GC task | |
| 295 #define _MARKING_STATS_ 0 | |
| 296 // this will enable the higher verbose levels | |
| 297 #define _MARKING_VERBOSE_ 0 | |
| 298 | |
| 299 #if _MARKING_STATS_ | |
| 300 #define statsOnly(statement) \ | |
| 301 do { \ | |
| 302 statement ; \ | |
| 303 } while (0) | |
| 304 #else // _MARKING_STATS_ | |
| 305 #define statsOnly(statement) \ | |
| 306 do { \ | |
| 307 } while (0) | |
| 308 #endif // _MARKING_STATS_ | |
| 309 | |
| 310 typedef enum { | |
| 311 no_verbose = 0, // verbose turned off | |
| 312 stats_verbose, // only prints stats at the end of marking | |
| 313 low_verbose, // low verbose, mostly per region and per major event | |
| 314 medium_verbose, // a bit more detailed than low | |
| 315 high_verbose // per object verbose | |
| 316 } CMVerboseLevel; | |
| 317 | |
| 318 | |
| 319 class ConcurrentMarkThread; | |
| 320 | |
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321 class ConcurrentMark: public CHeapObj { |
| 342 | 322 friend class ConcurrentMarkThread; |
| 323 friend class CMTask; | |
| 324 friend class CMBitMapClosure; | |
| 325 friend class CSMarkOopClosure; | |
| 326 friend class CMGlobalObjectClosure; | |
| 327 friend class CMRemarkTask; | |
| 328 friend class CMConcurrentMarkingTask; | |
| 329 friend class G1ParNoteEndTask; | |
| 330 friend class CalcLiveObjectsClosure; | |
| 331 | |
| 332 protected: | |
| 333 ConcurrentMarkThread* _cmThread; // the thread doing the work | |
| 334 G1CollectedHeap* _g1h; // the heap. | |
| 335 size_t _parallel_marking_threads; // the number of marking | |
| 336 // threads we'll use | |
| 337 double _sleep_factor; // how much we have to sleep, with | |
| 338 // respect to the work we just did, to | |
| 339 // meet the marking overhead goal | |
| 340 double _marking_task_overhead; // marking target overhead for | |
| 341 // a single task | |
| 342 | |
| 343 // same as the two above, but for the cleanup task | |
| 344 double _cleanup_sleep_factor; | |
| 345 double _cleanup_task_overhead; | |
| 346 | |
| 347 // Stuff related to age cohort processing. | |
| 348 struct ParCleanupThreadState { | |
| 349 char _pre[64]; | |
| 350 UncleanRegionList list; | |
| 351 char _post[64]; | |
| 352 }; | |
| 353 ParCleanupThreadState** _par_cleanup_thread_state; | |
| 354 | |
| 355 // CMS marking support structures | |
| 356 CMBitMap _markBitMap1; | |
| 357 CMBitMap _markBitMap2; | |
| 358 CMBitMapRO* _prevMarkBitMap; // completed mark bitmap | |
| 359 CMBitMap* _nextMarkBitMap; // under-construction mark bitmap | |
| 360 bool _at_least_one_mark_complete; | |
| 361 | |
| 362 BitMap _region_bm; | |
| 363 BitMap _card_bm; | |
| 364 | |
| 365 // Heap bounds | |
| 366 HeapWord* _heap_start; | |
| 367 HeapWord* _heap_end; | |
| 368 | |
| 369 // For gray objects | |
| 370 CMMarkStack _markStack; // Grey objects behind global finger. | |
| 371 CMRegionStack _regionStack; // Grey regions behind global finger. | |
| 372 HeapWord* volatile _finger; // the global finger, region aligned, | |
| 373 // always points to the end of the | |
| 374 // last claimed region | |
| 375 | |
| 376 // marking tasks | |
| 377 size_t _max_task_num; // maximum task number | |
| 378 size_t _active_tasks; // task num currently active | |
| 379 CMTask** _tasks; // task queue array (max_task_num len) | |
| 380 CMTaskQueueSet* _task_queues; // task queue set | |
| 381 ParallelTaskTerminator _terminator; // for termination | |
| 382 | |
| 383 // Two sync barriers that are used to synchronise tasks when an | |
| 384 // overflow occurs. The algorithm is the following. All tasks enter | |
| 385 // the first one to ensure that they have all stopped manipulating | |
| 386 // the global data structures. After they exit it, they re-initialise | |
| 387 // their data structures and task 0 re-initialises the global data | |
| 388 // structures. Then, they enter the second sync barrier. This | |
| 389 // ensure, that no task starts doing work before all data | |
| 390 // structures (local and global) have been re-initialised. When they | |
| 391 // exit it, they are free to start working again. | |
| 392 WorkGangBarrierSync _first_overflow_barrier_sync; | |
| 393 WorkGangBarrierSync _second_overflow_barrier_sync; | |
| 394 | |
| 395 | |
| 396 // this is set by any task, when an overflow on the global data | |
| 397 // structures is detected. | |
| 398 volatile bool _has_overflown; | |
| 399 // true: marking is concurrent, false: we're in remark | |
| 400 volatile bool _concurrent; | |
| 401 // set at the end of a Full GC so that marking aborts | |
| 402 volatile bool _has_aborted; | |
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403 |
| 342 | 404 // used when remark aborts due to an overflow to indicate that |
| 405 // another concurrent marking phase should start | |
| 406 volatile bool _restart_for_overflow; | |
| 407 | |
| 408 // This is true from the very start of concurrent marking until the | |
| 409 // point when all the tasks complete their work. It is really used | |
| 410 // to determine the points between the end of concurrent marking and | |
| 411 // time of remark. | |
| 412 volatile bool _concurrent_marking_in_progress; | |
| 413 | |
| 414 // verbose level | |
| 415 CMVerboseLevel _verbose_level; | |
| 416 | |
| 417 // These two fields are used to implement the optimisation that | |
| 418 // avoids pushing objects on the global/region stack if there are | |
| 419 // no collection set regions above the lowest finger. | |
| 420 | |
| 421 // This is the lowest finger (among the global and local fingers), | |
| 422 // which is calculated before a new collection set is chosen. | |
| 423 HeapWord* _min_finger; | |
| 424 // If this flag is true, objects/regions that are marked below the | |
| 425 // finger should be pushed on the stack(s). If this is flag is | |
| 426 // false, it is safe not to push them on the stack(s). | |
| 427 bool _should_gray_objects; | |
| 428 | |
| 429 // All of these times are in ms. | |
| 430 NumberSeq _init_times; | |
| 431 NumberSeq _remark_times; | |
| 432 NumberSeq _remark_mark_times; | |
| 433 NumberSeq _remark_weak_ref_times; | |
| 434 NumberSeq _cleanup_times; | |
| 435 double _total_counting_time; | |
| 436 double _total_rs_scrub_time; | |
| 437 | |
| 438 double* _accum_task_vtime; // accumulated task vtime | |
| 439 | |
| 440 WorkGang* _parallel_workers; | |
| 441 | |
| 442 void weakRefsWork(bool clear_all_soft_refs); | |
| 443 | |
| 444 void swapMarkBitMaps(); | |
| 445 | |
| 446 // It resets the global marking data structures, as well as the | |
| 447 // task local ones; should be called during initial mark. | |
| 448 void reset(); | |
| 449 // It resets all the marking data structures. | |
| 450 void clear_marking_state(); | |
| 451 | |
| 452 // It should be called to indicate which phase we're in (concurrent | |
| 453 // mark or remark) and how many threads are currently active. | |
| 454 void set_phase(size_t active_tasks, bool concurrent); | |
| 455 // We do this after we're done with marking so that the marking data | |
| 456 // structures are initialised to a sensible and predictable state. | |
| 457 void set_non_marking_state(); | |
| 458 | |
| 459 // prints all gathered CM-related statistics | |
| 460 void print_stats(); | |
| 461 | |
| 462 // accessor methods | |
| 463 size_t parallel_marking_threads() { return _parallel_marking_threads; } | |
| 464 double sleep_factor() { return _sleep_factor; } | |
| 465 double marking_task_overhead() { return _marking_task_overhead;} | |
| 466 double cleanup_sleep_factor() { return _cleanup_sleep_factor; } | |
| 467 double cleanup_task_overhead() { return _cleanup_task_overhead;} | |
| 468 | |
| 469 HeapWord* finger() { return _finger; } | |
| 470 bool concurrent() { return _concurrent; } | |
| 471 size_t active_tasks() { return _active_tasks; } | |
| 472 ParallelTaskTerminator* terminator() { return &_terminator; } | |
| 473 | |
| 474 // It claims the next available region to be scanned by a marking | |
| 475 // task. It might return NULL if the next region is empty or we have | |
| 476 // run out of regions. In the latter case, out_of_regions() | |
| 477 // determines whether we've really run out of regions or the task | |
| 478 // should call claim_region() again. This might seem a bit | |
| 479 // awkward. Originally, the code was written so that claim_region() | |
| 480 // either successfully returned with a non-empty region or there | |
| 481 // were no more regions to be claimed. The problem with this was | |
| 482 // that, in certain circumstances, it iterated over large chunks of | |
| 483 // the heap finding only empty regions and, while it was working, it | |
| 484 // was preventing the calling task to call its regular clock | |
| 485 // method. So, this way, each task will spend very little time in | |
| 486 // claim_region() and is allowed to call the regular clock method | |
| 487 // frequently. | |
| 488 HeapRegion* claim_region(int task); | |
| 489 | |
| 490 // It determines whether we've run out of regions to scan. | |
| 491 bool out_of_regions() { return _finger == _heap_end; } | |
| 492 | |
| 493 // Returns the task with the given id | |
| 494 CMTask* task(int id) { | |
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495 assert(0 <= id && id < (int) _active_tasks, |
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496 "task id not within active bounds"); |
| 342 | 497 return _tasks[id]; |
| 498 } | |
| 499 | |
| 500 // Returns the task queue with the given id | |
| 501 CMTaskQueue* task_queue(int id) { | |
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502 assert(0 <= id && id < (int) _active_tasks, |
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503 "task queue id not within active bounds"); |
| 342 | 504 return (CMTaskQueue*) _task_queues->queue(id); |
| 505 } | |
| 506 | |
| 507 // Returns the task queue set | |
| 508 CMTaskQueueSet* task_queues() { return _task_queues; } | |
| 509 | |
| 510 // Access / manipulation of the overflow flag which is set to | |
| 511 // indicate that the global stack or region stack has overflown | |
| 512 bool has_overflown() { return _has_overflown; } | |
| 513 void set_has_overflown() { _has_overflown = true; } | |
| 514 void clear_has_overflown() { _has_overflown = false; } | |
| 515 | |
| 516 bool has_aborted() { return _has_aborted; } | |
| 517 bool restart_for_overflow() { return _restart_for_overflow; } | |
| 518 | |
| 519 // Methods to enter the two overflow sync barriers | |
| 520 void enter_first_sync_barrier(int task_num); | |
| 521 void enter_second_sync_barrier(int task_num); | |
| 522 | |
| 523 public: | |
| 524 // Manipulation of the global mark stack. | |
| 525 // Notice that the first mark_stack_push is CAS-based, whereas the | |
| 526 // two below are Mutex-based. This is OK since the first one is only | |
| 527 // called during evacuation pauses and doesn't compete with the | |
| 528 // other two (which are called by the marking tasks during | |
| 529 // concurrent marking or remark). | |
| 530 bool mark_stack_push(oop p) { | |
| 531 _markStack.par_push(p); | |
| 532 if (_markStack.overflow()) { | |
| 533 set_has_overflown(); | |
| 534 return false; | |
| 535 } | |
| 536 return true; | |
| 537 } | |
| 538 bool mark_stack_push(oop* arr, int n) { | |
| 539 _markStack.par_push_arr(arr, n); | |
| 540 if (_markStack.overflow()) { | |
| 541 set_has_overflown(); | |
| 542 return false; | |
| 543 } | |
| 544 return true; | |
| 545 } | |
| 546 void mark_stack_pop(oop* arr, int max, int* n) { | |
| 547 _markStack.par_pop_arr(arr, max, n); | |
| 548 } | |
| 549 size_t mark_stack_size() { return _markStack.size(); } | |
| 550 size_t partial_mark_stack_size_target() { return _markStack.maxElems()/3; } | |
| 551 bool mark_stack_overflow() { return _markStack.overflow(); } | |
| 552 bool mark_stack_empty() { return _markStack.isEmpty(); } | |
| 553 | |
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554 // (Lock-free) Manipulation of the region stack |
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555 bool region_stack_push_lock_free(MemRegion mr) { |
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556 // Currently we only call the lock-free version during evacuation |
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557 // pauses. |
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558 assert(SafepointSynchronize::is_at_safepoint(), "world should be stopped"); |
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559 |
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560 _regionStack.push_lock_free(mr); |
| 342 | 561 if (_regionStack.overflow()) { |
| 562 set_has_overflown(); | |
| 563 return false; | |
| 564 } | |
| 565 return true; | |
| 566 } | |
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567 |
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568 // Lock-free version of region-stack pop. Should only be |
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569 // called in tandem with other lock-free pops. |
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570 MemRegion region_stack_pop_lock_free() { |
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571 return _regionStack.pop_lock_free(); |
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572 } |
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573 |
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574 #if 0 |
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575 // The routines that manipulate the region stack with a lock are |
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576 // not currently used. They should be retained, however, as a |
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577 // diagnostic aid. |
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578 |
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579 bool region_stack_push_with_lock(MemRegion mr) { |
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580 // Currently we only call the lock-based version during either |
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581 // concurrent marking or remark. |
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582 assert(!SafepointSynchronize::is_at_safepoint() || !concurrent(), |
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583 "if we are at a safepoint it should be the remark safepoint"); |
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584 |
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585 _regionStack.push_with_lock(mr); |
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586 if (_regionStack.overflow()) { |
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587 set_has_overflown(); |
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588 return false; |
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589 } |
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590 return true; |
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591 } |
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592 |
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593 MemRegion region_stack_pop_with_lock() { |
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594 // Currently we only call the lock-based version during either |
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595 // concurrent marking or remark. |
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596 assert(!SafepointSynchronize::is_at_safepoint() || !concurrent(), |
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597 "if we are at a safepoint it should be the remark safepoint"); |
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598 |
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599 return _regionStack.pop_with_lock(); |
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600 } |
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601 #endif |
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602 |
| 342 | 603 int region_stack_size() { return _regionStack.size(); } |
| 604 bool region_stack_overflow() { return _regionStack.overflow(); } | |
| 605 bool region_stack_empty() { return _regionStack.isEmpty(); } | |
| 606 | |
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607 // Iterate over any regions that were aborted while draining the |
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608 // region stack (any such regions are saved in the corresponding |
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609 // CMTask) and invalidate (i.e. assign to the empty MemRegion()) |
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610 // any regions that point into the collection set. |
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611 bool invalidate_aborted_regions_in_cset(); |
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612 |
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613 // Returns true if there are any aborted memory regions. |
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614 bool has_aborted_regions(); |
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615 |
| 342 | 616 bool concurrent_marking_in_progress() { |
| 617 return _concurrent_marking_in_progress; | |
| 618 } | |
| 619 void set_concurrent_marking_in_progress() { | |
| 620 _concurrent_marking_in_progress = true; | |
| 621 } | |
| 622 void clear_concurrent_marking_in_progress() { | |
| 623 _concurrent_marking_in_progress = false; | |
| 624 } | |
| 625 | |
| 626 void update_accum_task_vtime(int i, double vtime) { | |
| 627 _accum_task_vtime[i] += vtime; | |
| 628 } | |
| 629 | |
| 630 double all_task_accum_vtime() { | |
| 631 double ret = 0.0; | |
| 632 for (int i = 0; i < (int)_max_task_num; ++i) | |
| 633 ret += _accum_task_vtime[i]; | |
| 634 return ret; | |
| 635 } | |
| 636 | |
| 637 // Attempts to steal an object from the task queues of other tasks | |
| 638 bool try_stealing(int task_num, int* hash_seed, oop& obj) { | |
| 639 return _task_queues->steal(task_num, hash_seed, obj); | |
| 640 } | |
| 641 | |
| 642 // It grays an object by first marking it. Then, if it's behind the | |
| 643 // global finger, it also pushes it on the global stack. | |
| 644 void deal_with_reference(oop obj); | |
| 645 | |
| 646 ConcurrentMark(ReservedSpace rs, int max_regions); | |
| 647 ~ConcurrentMark(); | |
| 648 ConcurrentMarkThread* cmThread() { return _cmThread; } | |
| 649 | |
| 650 CMBitMapRO* prevMarkBitMap() const { return _prevMarkBitMap; } | |
| 651 CMBitMap* nextMarkBitMap() const { return _nextMarkBitMap; } | |
| 652 | |
| 653 // The following three are interaction between CM and | |
| 654 // G1CollectedHeap | |
| 655 | |
| 656 // This notifies CM that a root during initial-mark needs to be | |
| 657 // grayed and it's MT-safe. Currently, we just mark it. But, in the | |
| 658 // future, we can experiment with pushing it on the stack and we can | |
| 659 // do this without changing G1CollectedHeap. | |
| 660 void grayRoot(oop p); | |
| 661 // It's used during evacuation pauses to gray a region, if | |
| 662 // necessary, and it's MT-safe. It assumes that the caller has | |
| 663 // marked any objects on that region. If _should_gray_objects is | |
| 664 // true and we're still doing concurrent marking, the region is | |
| 665 // pushed on the region stack, if it is located below the global | |
| 666 // finger, otherwise we do nothing. | |
| 667 void grayRegionIfNecessary(MemRegion mr); | |
| 668 // It's used during evacuation pauses to mark and, if necessary, | |
| 669 // gray a single object and it's MT-safe. It assumes the caller did | |
| 670 // not mark the object. If _should_gray_objects is true and we're | |
| 671 // still doing concurrent marking, the objects is pushed on the | |
| 672 // global stack, if it is located below the global finger, otherwise | |
| 673 // we do nothing. | |
| 674 void markAndGrayObjectIfNecessary(oop p); | |
| 675 | |
| 1388 | 676 // It iterates over the heap and for each object it comes across it |
| 677 // will dump the contents of its reference fields, as well as | |
| 678 // liveness information for the object and its referents. The dump | |
| 679 // will be written to a file with the following name: | |
| 680 // G1PrintReachableBaseFile + "." + str. use_prev_marking decides | |
| 681 // whether the prev (use_prev_marking == true) or next | |
| 682 // (use_prev_marking == false) marking information will be used to | |
| 683 // determine the liveness of each object / referent. If all is true, | |
| 684 // all objects in the heap will be dumped, otherwise only the live | |
| 685 // ones. In the dump the following symbols / abbreviations are used: | |
| 686 // M : an explicitly live object (its bitmap bit is set) | |
| 687 // > : an implicitly live object (over tams) | |
| 688 // O : an object outside the G1 heap (typically: in the perm gen) | |
| 689 // NOT : a reference field whose referent is not live | |
| 690 // AND MARKED : indicates that an object is both explicitly and | |
| 691 // implicitly live (it should be one or the other, not both) | |
| 692 void print_reachable(const char* str, | |
| 693 bool use_prev_marking, bool all) PRODUCT_RETURN; | |
| 342 | 694 |
| 695 // Clear the next marking bitmap (will be called concurrently). | |
| 696 void clearNextBitmap(); | |
| 697 | |
| 698 // main CMS steps and related support | |
| 699 void checkpointRootsInitial(); | |
| 700 | |
| 701 // These two do the work that needs to be done before and after the | |
| 702 // initial root checkpoint. Since this checkpoint can be done at two | |
| 703 // different points (i.e. an explicit pause or piggy-backed on a | |
| 704 // young collection), then it's nice to be able to easily share the | |
| 705 // pre/post code. It might be the case that we can put everything in | |
| 706 // the post method. TP | |
| 707 void checkpointRootsInitialPre(); | |
| 708 void checkpointRootsInitialPost(); | |
| 709 | |
| 710 // Do concurrent phase of marking, to a tentative transitive closure. | |
| 711 void markFromRoots(); | |
| 712 | |
| 713 // Process all unprocessed SATB buffers. It is called at the | |
| 714 // beginning of an evacuation pause. | |
| 715 void drainAllSATBBuffers(); | |
| 716 | |
| 717 void checkpointRootsFinal(bool clear_all_soft_refs); | |
| 718 void checkpointRootsFinalWork(); | |
| 719 void calcDesiredRegions(); | |
| 720 void cleanup(); | |
| 721 void completeCleanup(); | |
| 722 | |
| 723 // Mark in the previous bitmap. NB: this is usually read-only, so use | |
| 724 // this carefully! | |
| 725 void markPrev(oop p); | |
| 726 void clear(oop p); | |
| 727 // Clears marks for all objects in the given range, for both prev and | |
| 728 // next bitmaps. NB: the previous bitmap is usually read-only, so use | |
| 729 // this carefully! | |
| 730 void clearRangeBothMaps(MemRegion mr); | |
| 731 | |
| 732 // Record the current top of the mark and region stacks; a | |
| 733 // subsequent oops_do() on the mark stack and | |
| 734 // invalidate_entries_into_cset() on the region stack will iterate | |
| 735 // only over indices valid at the time of this call. | |
| 736 void set_oops_do_bound() { | |
| 737 _markStack.set_oops_do_bound(); | |
| 738 _regionStack.set_oops_do_bound(); | |
| 739 } | |
| 740 // Iterate over the oops in the mark stack and all local queues. It | |
| 741 // also calls invalidate_entries_into_cset() on the region stack. | |
| 742 void oops_do(OopClosure* f); | |
| 743 // It is called at the end of an evacuation pause during marking so | |
| 744 // that CM is notified of where the new end of the heap is. It | |
| 745 // doesn't do anything if concurrent_marking_in_progress() is false, | |
| 746 // unless the force parameter is true. | |
| 747 void update_g1_committed(bool force = false); | |
| 748 | |
| 749 void complete_marking_in_collection_set(); | |
| 750 | |
| 751 // It indicates that a new collection set is being chosen. | |
| 752 void newCSet(); | |
| 753 // It registers a collection set heap region with CM. This is used | |
| 754 // to determine whether any heap regions are located above the finger. | |
| 755 void registerCSetRegion(HeapRegion* hr); | |
| 756 | |
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757 // Registers the maximum region-end associated with a set of |
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758 // regions with CM. Again this is used to determine whether any |
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759 // heap regions are located above the finger. |
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760 void register_collection_set_finger(HeapWord* max_finger) { |
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761 // max_finger is the highest heap region end of the regions currently |
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762 // contained in the collection set. If this value is larger than |
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763 // _min_finger then we need to gray objects. |
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764 // This routine is like registerCSetRegion but for an entire |
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765 // collection of regions. |
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766 if (max_finger > _min_finger) |
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767 _should_gray_objects = true; |
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768 } |
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769 |
| 342 | 770 // Returns "true" if at least one mark has been completed. |
| 771 bool at_least_one_mark_complete() { return _at_least_one_mark_complete; } | |
| 772 | |
| 773 bool isMarked(oop p) const { | |
| 774 assert(p != NULL && p->is_oop(), "expected an oop"); | |
| 775 HeapWord* addr = (HeapWord*)p; | |
| 776 assert(addr >= _nextMarkBitMap->startWord() || | |
| 777 addr < _nextMarkBitMap->endWord(), "in a region"); | |
| 778 | |
| 779 return _nextMarkBitMap->isMarked(addr); | |
| 780 } | |
| 781 | |
| 782 inline bool not_yet_marked(oop p) const; | |
| 783 | |
| 784 // XXX Debug code | |
| 785 bool containing_card_is_marked(void* p); | |
| 786 bool containing_cards_are_marked(void* start, void* last); | |
| 787 | |
| 788 bool isPrevMarked(oop p) const { | |
| 789 assert(p != NULL && p->is_oop(), "expected an oop"); | |
| 790 HeapWord* addr = (HeapWord*)p; | |
| 791 assert(addr >= _prevMarkBitMap->startWord() || | |
| 792 addr < _prevMarkBitMap->endWord(), "in a region"); | |
| 793 | |
| 794 return _prevMarkBitMap->isMarked(addr); | |
| 795 } | |
| 796 | |
| 797 inline bool do_yield_check(int worker_i = 0); | |
| 798 inline bool should_yield(); | |
| 799 | |
| 800 // Called to abort the marking cycle after a Full GC takes palce. | |
| 801 void abort(); | |
| 802 | |
| 803 // This prints the global/local fingers. It is used for debugging. | |
| 804 NOT_PRODUCT(void print_finger();) | |
| 805 | |
| 806 void print_summary_info(); | |
| 807 | |
| 1019 | 808 void print_worker_threads_on(outputStream* st) const; |
| 809 | |
| 342 | 810 // The following indicate whether a given verbose level has been |
| 811 // set. Notice that anything above stats is conditional to | |
| 812 // _MARKING_VERBOSE_ having been set to 1 | |
| 813 bool verbose_stats() | |
| 814 { return _verbose_level >= stats_verbose; } | |
| 815 bool verbose_low() | |
| 816 { return _MARKING_VERBOSE_ && _verbose_level >= low_verbose; } | |
| 817 bool verbose_medium() | |
| 818 { return _MARKING_VERBOSE_ && _verbose_level >= medium_verbose; } | |
| 819 bool verbose_high() | |
| 820 { return _MARKING_VERBOSE_ && _verbose_level >= high_verbose; } | |
| 821 }; | |
| 822 | |
| 823 // A class representing a marking task. | |
| 824 class CMTask : public TerminatorTerminator { | |
| 825 private: | |
| 826 enum PrivateConstants { | |
| 827 // the regular clock call is called once the scanned words reaches | |
| 828 // this limit | |
| 829 words_scanned_period = 12*1024, | |
| 830 // the regular clock call is called once the number of visited | |
| 831 // references reaches this limit | |
| 832 refs_reached_period = 384, | |
| 833 // initial value for the hash seed, used in the work stealing code | |
| 834 init_hash_seed = 17, | |
| 835 // how many entries will be transferred between global stack and | |
| 836 // local queues | |
| 837 global_stack_transfer_size = 16 | |
| 838 }; | |
| 839 | |
| 840 int _task_id; | |
| 841 G1CollectedHeap* _g1h; | |
| 842 ConcurrentMark* _cm; | |
| 843 CMBitMap* _nextMarkBitMap; | |
| 844 // the task queue of this task | |
| 845 CMTaskQueue* _task_queue; | |
|
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846 private: |
| 342 | 847 // the task queue set---needed for stealing |
| 848 CMTaskQueueSet* _task_queues; | |
| 849 // indicates whether the task has been claimed---this is only for | |
| 850 // debugging purposes | |
| 851 bool _claimed; | |
| 852 | |
| 853 // number of calls to this task | |
| 854 int _calls; | |
| 855 | |
| 856 // when the virtual timer reaches this time, the marking step should | |
| 857 // exit | |
| 858 double _time_target_ms; | |
| 859 // the start time of the current marking step | |
| 860 double _start_time_ms; | |
| 861 | |
| 862 // the oop closure used for iterations over oops | |
| 863 OopClosure* _oop_closure; | |
| 864 | |
| 865 // the region this task is scanning, NULL if we're not scanning any | |
| 866 HeapRegion* _curr_region; | |
| 867 // the local finger of this task, NULL if we're not scanning a region | |
| 868 HeapWord* _finger; | |
| 869 // limit of the region this task is scanning, NULL if we're not scanning one | |
| 870 HeapWord* _region_limit; | |
| 871 | |
| 872 // This is used only when we scan regions popped from the region | |
| 873 // stack. It records what the last object on such a region we | |
| 874 // scanned was. It is used to ensure that, if we abort region | |
| 875 // iteration, we do not rescan the first part of the region. This | |
| 876 // should be NULL when we're not scanning a region from the region | |
| 877 // stack. | |
| 878 HeapWord* _region_finger; | |
| 879 | |
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880 // If we abort while scanning a region we record the remaining |
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881 // unscanned portion and check this field when marking restarts. |
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882 // This avoids having to push on the region stack while other |
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883 // marking threads may still be popping regions. |
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884 // If we were to push the unscanned portion directly to the |
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885 // region stack then we would need to using locking versions |
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886 // of the push and pop operations. |
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887 MemRegion _aborted_region; |
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888 |
| 342 | 889 // the number of words this task has scanned |
| 890 size_t _words_scanned; | |
| 891 // When _words_scanned reaches this limit, the regular clock is | |
| 892 // called. Notice that this might be decreased under certain | |
| 893 // circumstances (i.e. when we believe that we did an expensive | |
| 894 // operation). | |
| 895 size_t _words_scanned_limit; | |
| 896 // the initial value of _words_scanned_limit (i.e. what it was | |
| 897 // before it was decreased). | |
| 898 size_t _real_words_scanned_limit; | |
| 899 | |
| 900 // the number of references this task has visited | |
| 901 size_t _refs_reached; | |
| 902 // When _refs_reached reaches this limit, the regular clock is | |
| 903 // called. Notice this this might be decreased under certain | |
| 904 // circumstances (i.e. when we believe that we did an expensive | |
| 905 // operation). | |
| 906 size_t _refs_reached_limit; | |
| 907 // the initial value of _refs_reached_limit (i.e. what it was before | |
| 908 // it was decreased). | |
| 909 size_t _real_refs_reached_limit; | |
| 910 | |
| 911 // used by the work stealing stuff | |
| 912 int _hash_seed; | |
| 913 // if this is true, then the task has aborted for some reason | |
| 914 bool _has_aborted; | |
| 915 // set when the task aborts because it has met its time quota | |
| 916 bool _has_aborted_timed_out; | |
| 917 // true when we're draining SATB buffers; this avoids the task | |
| 918 // aborting due to SATB buffers being available (as we're already | |
| 919 // dealing with them) | |
| 920 bool _draining_satb_buffers; | |
| 921 | |
| 922 // number sequence of past step times | |
| 923 NumberSeq _step_times_ms; | |
| 924 // elapsed time of this task | |
| 925 double _elapsed_time_ms; | |
| 926 // termination time of this task | |
| 927 double _termination_time_ms; | |
| 928 // when this task got into the termination protocol | |
| 929 double _termination_start_time_ms; | |
| 930 | |
| 931 // true when the task is during a concurrent phase, false when it is | |
| 932 // in the remark phase (so, in the latter case, we do not have to | |
| 933 // check all the things that we have to check during the concurrent | |
| 934 // phase, i.e. SATB buffer availability...) | |
| 935 bool _concurrent; | |
| 936 | |
| 937 TruncatedSeq _marking_step_diffs_ms; | |
| 938 | |
| 939 // LOTS of statistics related with this task | |
| 940 #if _MARKING_STATS_ | |
| 941 NumberSeq _all_clock_intervals_ms; | |
| 942 double _interval_start_time_ms; | |
| 943 | |
| 944 int _aborted; | |
| 945 int _aborted_overflow; | |
| 946 int _aborted_cm_aborted; | |
| 947 int _aborted_yield; | |
| 948 int _aborted_timed_out; | |
| 949 int _aborted_satb; | |
| 950 int _aborted_termination; | |
| 951 | |
| 952 int _steal_attempts; | |
| 953 int _steals; | |
| 954 | |
| 955 int _clock_due_to_marking; | |
| 956 int _clock_due_to_scanning; | |
| 957 | |
| 958 int _local_pushes; | |
| 959 int _local_pops; | |
| 960 int _local_max_size; | |
| 961 int _objs_scanned; | |
| 962 | |
| 963 int _global_pushes; | |
| 964 int _global_pops; | |
| 965 int _global_max_size; | |
| 966 | |
| 967 int _global_transfers_to; | |
| 968 int _global_transfers_from; | |
| 969 | |
| 970 int _region_stack_pops; | |
| 971 | |
| 972 int _regions_claimed; | |
| 973 int _objs_found_on_bitmap; | |
| 974 | |
| 975 int _satb_buffers_processed; | |
| 976 #endif // _MARKING_STATS_ | |
| 977 | |
| 978 // it updates the local fields after this task has claimed | |
| 979 // a new region to scan | |
| 980 void setup_for_region(HeapRegion* hr); | |
| 981 // it brings up-to-date the limit of the region | |
| 982 void update_region_limit(); | |
| 983 // it resets the local fields after a task has finished scanning a | |
| 984 // region | |
| 985 void giveup_current_region(); | |
| 986 | |
| 987 // called when either the words scanned or the refs visited limit | |
| 988 // has been reached | |
| 989 void reached_limit(); | |
| 990 // recalculates the words scanned and refs visited limits | |
| 991 void recalculate_limits(); | |
| 992 // decreases the words scanned and refs visited limits when we reach | |
| 993 // an expensive operation | |
| 994 void decrease_limits(); | |
| 995 // it checks whether the words scanned or refs visited reached their | |
| 996 // respective limit and calls reached_limit() if they have | |
| 997 void check_limits() { | |
| 998 if (_words_scanned >= _words_scanned_limit || | |
| 999 _refs_reached >= _refs_reached_limit) | |
| 1000 reached_limit(); | |
| 1001 } | |
| 1002 // this is supposed to be called regularly during a marking step as | |
| 1003 // it checks a bunch of conditions that might cause the marking step | |
| 1004 // to abort | |
| 1005 void regular_clock_call(); | |
| 1006 bool concurrent() { return _concurrent; } | |
| 1007 | |
| 1008 public: | |
| 1009 // It resets the task; it should be called right at the beginning of | |
| 1010 // a marking phase. | |
| 1011 void reset(CMBitMap* _nextMarkBitMap); | |
| 1012 // it clears all the fields that correspond to a claimed region. | |
| 1013 void clear_region_fields(); | |
| 1014 | |
| 1015 void set_concurrent(bool concurrent) { _concurrent = concurrent; } | |
| 1016 | |
| 1017 // The main method of this class which performs a marking step | |
| 1018 // trying not to exceed the given duration. However, it might exit | |
| 1019 // prematurely, according to some conditions (i.e. SATB buffers are | |
| 1020 // available for processing). | |
| 1021 void do_marking_step(double target_ms); | |
| 1022 | |
| 1023 // These two calls start and stop the timer | |
| 1024 void record_start_time() { | |
| 1025 _elapsed_time_ms = os::elapsedTime() * 1000.0; | |
| 1026 } | |
| 1027 void record_end_time() { | |
| 1028 _elapsed_time_ms = os::elapsedTime() * 1000.0 - _elapsed_time_ms; | |
| 1029 } | |
| 1030 | |
| 1031 // returns the task ID | |
| 1032 int task_id() { return _task_id; } | |
| 1033 | |
| 1034 // From TerminatorTerminator. It determines whether this task should | |
| 1035 // exit the termination protocol after it's entered it. | |
| 1036 virtual bool should_exit_termination(); | |
| 1037 | |
| 1038 HeapWord* finger() { return _finger; } | |
| 1039 | |
| 1040 bool has_aborted() { return _has_aborted; } | |
| 1041 void set_has_aborted() { _has_aborted = true; } | |
| 1042 void clear_has_aborted() { _has_aborted = false; } | |
| 1043 bool claimed() { return _claimed; } | |
| 1044 | |
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1045 // Support routines for the partially scanned region that may be |
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1046 // recorded as a result of aborting while draining the CMRegionStack |
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1047 MemRegion aborted_region() { return _aborted_region; } |
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1048 void set_aborted_region(MemRegion mr) |
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1049 { _aborted_region = mr; } |
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1050 |
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1051 // Clears any recorded partially scanned region |
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1052 void clear_aborted_region() { set_aborted_region(MemRegion()); } |
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1053 |
| 342 | 1054 void set_oop_closure(OopClosure* oop_closure) { |
| 1055 _oop_closure = oop_closure; | |
| 1056 } | |
| 1057 | |
| 1058 // It grays the object by marking it and, if necessary, pushing it | |
| 1059 // on the local queue | |
| 1060 void deal_with_reference(oop obj); | |
| 1061 | |
| 1062 // It scans an object and visits its children. | |
| 1063 void scan_object(oop obj) { | |
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1064 assert(_nextMarkBitMap->isMarked((HeapWord*) obj), "invariant"); |
| 342 | 1065 |
| 1066 if (_cm->verbose_high()) | |
| 1067 gclog_or_tty->print_cr("[%d] we're scanning object "PTR_FORMAT, | |
| 1068 _task_id, (void*) obj); | |
| 1069 | |
| 1070 size_t obj_size = obj->size(); | |
| 1071 _words_scanned += obj_size; | |
| 1072 | |
| 1073 obj->oop_iterate(_oop_closure); | |
| 1074 statsOnly( ++_objs_scanned ); | |
| 1075 check_limits(); | |
| 1076 } | |
| 1077 | |
| 1078 // It pushes an object on the local queue. | |
| 1079 void push(oop obj); | |
| 1080 | |
| 1081 // These two move entries to/from the global stack. | |
| 1082 void move_entries_to_global_stack(); | |
| 1083 void get_entries_from_global_stack(); | |
| 1084 | |
| 1085 // It pops and scans objects from the local queue. If partially is | |
| 1086 // true, then it stops when the queue size is of a given limit. If | |
| 1087 // partially is false, then it stops when the queue is empty. | |
| 1088 void drain_local_queue(bool partially); | |
| 1089 // It moves entries from the global stack to the local queue and | |
| 1090 // drains the local queue. If partially is true, then it stops when | |
| 1091 // both the global stack and the local queue reach a given size. If | |
| 1092 // partially if false, it tries to empty them totally. | |
| 1093 void drain_global_stack(bool partially); | |
| 1094 // It keeps picking SATB buffers and processing them until no SATB | |
| 1095 // buffers are available. | |
| 1096 void drain_satb_buffers(); | |
| 1097 // It keeps popping regions from the region stack and processing | |
| 1098 // them until the region stack is empty. | |
| 1099 void drain_region_stack(BitMapClosure* closure); | |
| 1100 | |
| 1101 // moves the local finger to a new location | |
| 1102 inline void move_finger_to(HeapWord* new_finger) { | |
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1103 assert(new_finger >= _finger && new_finger < _region_limit, "invariant"); |
| 342 | 1104 _finger = new_finger; |
| 1105 } | |
| 1106 | |
| 1107 // moves the region finger to a new location | |
| 1108 inline void move_region_finger_to(HeapWord* new_finger) { | |
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1109 assert(new_finger < _cm->finger(), "invariant"); |
| 342 | 1110 _region_finger = new_finger; |
| 1111 } | |
| 1112 | |
| 1113 CMTask(int task_num, ConcurrentMark *cm, | |
| 1114 CMTaskQueue* task_queue, CMTaskQueueSet* task_queues); | |
| 1115 | |
| 1116 // it prints statistics associated with this task | |
| 1117 void print_stats(); | |
| 1118 | |
| 1119 #if _MARKING_STATS_ | |
| 1120 void increase_objs_found_on_bitmap() { ++_objs_found_on_bitmap; } | |
| 1121 #endif // _MARKING_STATS_ | |
| 1122 }; |