Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.hpp @ 1836:894b1d7c7e01
6423256: GC stacks should use a better data structure
6942771: SEGV in ParScanThreadState::take_from_overflow_stack
Reviewed-by: apetrusenko, ysr, pbk
| author | jcoomes |
|---|---|
| date | Tue, 28 Sep 2010 15:56:15 -0700 |
| parents | 8b10f48633dc |
| children | a7214d79fcf1 |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved. |
| 0 | 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. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 25 // ConcurrentMarkSweepGeneration is in support of a concurrent | |
| 26 // mark-sweep old generation in the Detlefs-Printezis--Boehm-Demers-Schenker | |
| 27 // style. We assume, for now, that this generation is always the | |
| 28 // seniormost generation (modulo the PermGeneration), and for simplicity | |
| 29 // in the first implementation, that this generation is a single compactible | |
| 30 // space. Neither of these restrictions appears essential, and will be | |
| 31 // relaxed in the future when more time is available to implement the | |
| 32 // greater generality (and there's a need for it). | |
| 33 // | |
| 34 // Concurrent mode failures are currently handled by | |
| 35 // means of a sliding mark-compact. | |
| 36 | |
| 37 class CMSAdaptiveSizePolicy; | |
| 38 class CMSConcMarkingTask; | |
| 39 class CMSGCAdaptivePolicyCounters; | |
| 40 class ConcurrentMarkSweepGeneration; | |
| 41 class ConcurrentMarkSweepPolicy; | |
| 42 class ConcurrentMarkSweepThread; | |
| 43 class CompactibleFreeListSpace; | |
| 44 class FreeChunk; | |
| 45 class PromotionInfo; | |
| 46 class ScanMarkedObjectsAgainCarefullyClosure; | |
| 47 | |
| 48 // A generic CMS bit map. It's the basis for both the CMS marking bit map | |
| 49 // as well as for the mod union table (in each case only a subset of the | |
| 50 // methods are used). This is essentially a wrapper around the BitMap class, | |
| 51 // with one bit per (1<<_shifter) HeapWords. (i.e. for the marking bit map, | |
| 52 // we have _shifter == 0. and for the mod union table we have | |
| 53 // shifter == CardTableModRefBS::card_shift - LogHeapWordSize.) | |
| 54 // XXX 64-bit issues in BitMap? | |
| 55 class CMSBitMap VALUE_OBJ_CLASS_SPEC { | |
| 56 friend class VMStructs; | |
| 57 | |
| 58 HeapWord* _bmStartWord; // base address of range covered by map | |
| 59 size_t _bmWordSize; // map size (in #HeapWords covered) | |
| 60 const int _shifter; // shifts to convert HeapWord to bit position | |
| 61 VirtualSpace _virtual_space; // underlying the bit map | |
| 62 BitMap _bm; // the bit map itself | |
| 63 public: | |
| 64 Mutex* const _lock; // mutex protecting _bm; | |
| 65 | |
| 66 public: | |
| 67 // constructor | |
| 68 CMSBitMap(int shifter, int mutex_rank, const char* mutex_name); | |
| 69 | |
| 70 // allocates the actual storage for the map | |
| 71 bool allocate(MemRegion mr); | |
| 72 // field getter | |
| 73 Mutex* lock() const { return _lock; } | |
| 74 // locking verifier convenience function | |
| 75 void assert_locked() const PRODUCT_RETURN; | |
| 76 | |
| 77 // inquiries | |
| 78 HeapWord* startWord() const { return _bmStartWord; } | |
| 79 size_t sizeInWords() const { return _bmWordSize; } | |
| 80 size_t sizeInBits() const { return _bm.size(); } | |
| 81 // the following is one past the last word in space | |
| 82 HeapWord* endWord() const { return _bmStartWord + _bmWordSize; } | |
| 83 | |
| 84 // reading marks | |
| 85 bool isMarked(HeapWord* addr) const; | |
| 86 bool par_isMarked(HeapWord* addr) const; // do not lock checks | |
| 87 bool isUnmarked(HeapWord* addr) const; | |
| 88 bool isAllClear() const; | |
| 89 | |
| 90 // writing marks | |
| 91 void mark(HeapWord* addr); | |
| 92 // For marking by parallel GC threads; | |
| 93 // returns true if we did, false if another thread did | |
| 94 bool par_mark(HeapWord* addr); | |
| 95 | |
| 96 void mark_range(MemRegion mr); | |
| 97 void par_mark_range(MemRegion mr); | |
| 98 void mark_large_range(MemRegion mr); | |
| 99 void par_mark_large_range(MemRegion mr); | |
| 100 void par_clear(HeapWord* addr); // For unmarking by parallel GC threads. | |
| 101 void clear_range(MemRegion mr); | |
| 102 void par_clear_range(MemRegion mr); | |
| 103 void clear_large_range(MemRegion mr); | |
| 104 void par_clear_large_range(MemRegion mr); | |
| 105 void clear_all(); | |
| 106 void clear_all_incrementally(); // Not yet implemented!! | |
| 107 | |
| 108 NOT_PRODUCT( | |
| 109 // checks the memory region for validity | |
| 110 void region_invariant(MemRegion mr); | |
| 111 ) | |
| 112 | |
| 113 // iteration | |
| 114 void iterate(BitMapClosure* cl) { | |
| 115 _bm.iterate(cl); | |
| 116 } | |
| 117 void iterate(BitMapClosure* cl, HeapWord* left, HeapWord* right); | |
| 118 void dirty_range_iterate_clear(MemRegionClosure* cl); | |
| 119 void dirty_range_iterate_clear(MemRegion mr, MemRegionClosure* cl); | |
| 120 | |
| 121 // auxiliary support for iteration | |
| 122 HeapWord* getNextMarkedWordAddress(HeapWord* addr) const; | |
| 123 HeapWord* getNextMarkedWordAddress(HeapWord* start_addr, | |
| 124 HeapWord* end_addr) const; | |
| 125 HeapWord* getNextUnmarkedWordAddress(HeapWord* addr) const; | |
| 126 HeapWord* getNextUnmarkedWordAddress(HeapWord* start_addr, | |
| 127 HeapWord* end_addr) const; | |
| 128 MemRegion getAndClearMarkedRegion(HeapWord* addr); | |
| 129 MemRegion getAndClearMarkedRegion(HeapWord* start_addr, | |
| 130 HeapWord* end_addr); | |
| 131 | |
| 132 // conversion utilities | |
| 133 HeapWord* offsetToHeapWord(size_t offset) const; | |
| 134 size_t heapWordToOffset(HeapWord* addr) const; | |
| 135 size_t heapWordDiffToOffsetDiff(size_t diff) const; | |
| 136 | |
| 137 // debugging | |
| 138 // is this address range covered by the bit-map? | |
| 139 NOT_PRODUCT( | |
| 140 bool covers(MemRegion mr) const; | |
| 141 bool covers(HeapWord* start, size_t size = 0) const; | |
| 142 ) | |
| 143 void verifyNoOneBitsInRange(HeapWord* left, HeapWord* right) PRODUCT_RETURN; | |
| 144 }; | |
| 145 | |
| 146 // Represents a marking stack used by the CMS collector. | |
| 147 // Ideally this should be GrowableArray<> just like MSC's marking stack(s). | |
| 148 class CMSMarkStack: public CHeapObj { | |
| 149 // | |
| 150 friend class CMSCollector; // to get at expasion stats further below | |
| 151 // | |
| 152 | |
| 153 VirtualSpace _virtual_space; // space for the stack | |
| 154 oop* _base; // bottom of stack | |
| 155 size_t _index; // one more than last occupied index | |
| 156 size_t _capacity; // max #elements | |
| 157 Mutex _par_lock; // an advisory lock used in case of parallel access | |
| 158 NOT_PRODUCT(size_t _max_depth;) // max depth plumbed during run | |
| 159 | |
| 160 protected: | |
| 161 size_t _hit_limit; // we hit max stack size limit | |
| 162 size_t _failed_double; // we failed expansion before hitting limit | |
| 163 | |
| 164 public: | |
| 165 CMSMarkStack(): | |
| 166 _par_lock(Mutex::event, "CMSMarkStack._par_lock", true), | |
| 167 _hit_limit(0), | |
| 168 _failed_double(0) {} | |
| 169 | |
| 170 bool allocate(size_t size); | |
| 171 | |
| 172 size_t capacity() const { return _capacity; } | |
| 173 | |
| 174 oop pop() { | |
| 175 if (!isEmpty()) { | |
| 176 return _base[--_index] ; | |
| 177 } | |
| 178 return NULL; | |
| 179 } | |
| 180 | |
| 181 bool push(oop ptr) { | |
| 182 if (isFull()) { | |
| 183 return false; | |
| 184 } else { | |
| 185 _base[_index++] = ptr; | |
| 186 NOT_PRODUCT(_max_depth = MAX2(_max_depth, _index)); | |
| 187 return true; | |
| 188 } | |
| 189 } | |
| 190 | |
| 191 bool isEmpty() const { return _index == 0; } | |
| 192 bool isFull() const { | |
| 193 assert(_index <= _capacity, "buffer overflow"); | |
| 194 return _index == _capacity; | |
| 195 } | |
| 196 | |
| 197 size_t length() { return _index; } | |
| 198 | |
| 199 // "Parallel versions" of some of the above | |
| 200 oop par_pop() { | |
| 201 // lock and pop | |
| 202 MutexLockerEx x(&_par_lock, Mutex::_no_safepoint_check_flag); | |
| 203 return pop(); | |
| 204 } | |
| 205 | |
| 206 bool par_push(oop ptr) { | |
| 207 // lock and push | |
| 208 MutexLockerEx x(&_par_lock, Mutex::_no_safepoint_check_flag); | |
| 209 return push(ptr); | |
| 210 } | |
| 211 | |
| 212 // Forcibly reset the stack, losing all of its contents. | |
| 213 void reset() { | |
| 214 _index = 0; | |
| 215 } | |
| 216 | |
| 217 // Expand the stack, typically in response to an overflow condition | |
| 218 void expand(); | |
| 219 | |
| 220 // Compute the least valued stack element. | |
| 221 oop least_value(HeapWord* low) { | |
| 222 oop least = (oop)low; | |
| 223 for (size_t i = 0; i < _index; i++) { | |
| 224 least = MIN2(least, _base[i]); | |
| 225 } | |
| 226 return least; | |
| 227 } | |
| 228 | |
| 229 // Exposed here to allow stack expansion in || case | |
| 230 Mutex* par_lock() { return &_par_lock; } | |
| 231 }; | |
| 232 | |
| 233 class CardTableRS; | |
| 234 class CMSParGCThreadState; | |
| 235 | |
| 236 class ModUnionClosure: public MemRegionClosure { | |
| 237 protected: | |
| 238 CMSBitMap* _t; | |
| 239 public: | |
| 240 ModUnionClosure(CMSBitMap* t): _t(t) { } | |
| 241 void do_MemRegion(MemRegion mr); | |
| 242 }; | |
| 243 | |
| 244 class ModUnionClosurePar: public ModUnionClosure { | |
| 245 public: | |
| 246 ModUnionClosurePar(CMSBitMap* t): ModUnionClosure(t) { } | |
| 247 void do_MemRegion(MemRegion mr); | |
| 248 }; | |
| 249 | |
| 250 // Survivor Chunk Array in support of parallelization of | |
| 251 // Survivor Space rescan. | |
| 252 class ChunkArray: public CHeapObj { | |
| 253 size_t _index; | |
| 254 size_t _capacity; | |
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255 size_t _overflows; |
| 0 | 256 HeapWord** _array; // storage for array |
| 257 | |
| 258 public: | |
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259 ChunkArray() : _index(0), _capacity(0), _overflows(0), _array(NULL) {} |
| 0 | 260 ChunkArray(HeapWord** a, size_t c): |
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261 _index(0), _capacity(c), _overflows(0), _array(a) {} |
| 0 | 262 |
| 263 HeapWord** array() { return _array; } | |
| 264 void set_array(HeapWord** a) { _array = a; } | |
| 265 | |
| 266 size_t capacity() { return _capacity; } | |
| 267 void set_capacity(size_t c) { _capacity = c; } | |
| 268 | |
| 269 size_t end() { | |
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270 assert(_index <= capacity(), |
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271 err_msg("_index (" SIZE_FORMAT ") > _capacity (" SIZE_FORMAT "): out of bounds", |
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272 _index, _capacity)); |
| 0 | 273 return _index; |
| 274 } // exclusive | |
| 275 | |
| 276 HeapWord* nth(size_t n) { | |
| 277 assert(n < end(), "Out of bounds access"); | |
| 278 return _array[n]; | |
| 279 } | |
| 280 | |
| 281 void reset() { | |
| 282 _index = 0; | |
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283 if (_overflows > 0 && PrintCMSStatistics > 1) { |
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284 warning("CMS: ChunkArray[" SIZE_FORMAT "] overflowed " SIZE_FORMAT " times", |
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285 _capacity, _overflows); |
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286 } |
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287 _overflows = 0; |
| 0 | 288 } |
| 289 | |
| 290 void record_sample(HeapWord* p, size_t sz) { | |
| 291 // For now we do not do anything with the size | |
| 292 if (_index < _capacity) { | |
| 293 _array[_index++] = p; | |
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294 } else { |
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295 ++_overflows; |
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296 assert(_index == _capacity, |
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297 err_msg("_index (" SIZE_FORMAT ") > _capacity (" SIZE_FORMAT |
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298 "): out of bounds at overflow#" SIZE_FORMAT, |
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299 _index, _capacity, _overflows)); |
| 0 | 300 } |
| 301 } | |
| 302 }; | |
| 303 | |
| 304 // | |
| 305 // Timing, allocation and promotion statistics for gc scheduling and incremental | |
| 306 // mode pacing. Most statistics are exponential averages. | |
| 307 // | |
| 308 class CMSStats VALUE_OBJ_CLASS_SPEC { | |
| 309 private: | |
| 310 ConcurrentMarkSweepGeneration* const _cms_gen; // The cms (old) gen. | |
| 311 | |
| 312 // The following are exponential averages with factor alpha: | |
| 313 // avg = (100 - alpha) * avg + alpha * cur_sample | |
| 314 // | |
| 315 // The durations measure: end_time[n] - start_time[n] | |
| 316 // The periods measure: start_time[n] - start_time[n-1] | |
| 317 // | |
| 318 // The cms period and duration include only concurrent collections; time spent | |
| 319 // in foreground cms collections due to System.gc() or because of a failure to | |
| 320 // keep up are not included. | |
| 321 // | |
| 322 // There are 3 alphas to "bootstrap" the statistics. The _saved_alpha is the | |
| 323 // real value, but is used only after the first period. A value of 100 is | |
| 324 // used for the first sample so it gets the entire weight. | |
| 325 unsigned int _saved_alpha; // 0-100 | |
| 326 unsigned int _gc0_alpha; | |
| 327 unsigned int _cms_alpha; | |
| 328 | |
| 329 double _gc0_duration; | |
| 330 double _gc0_period; | |
| 331 size_t _gc0_promoted; // bytes promoted per gc0 | |
| 332 double _cms_duration; | |
| 333 double _cms_duration_pre_sweep; // time from initiation to start of sweep | |
| 334 double _cms_duration_per_mb; | |
| 335 double _cms_period; | |
| 336 size_t _cms_allocated; // bytes of direct allocation per gc0 period | |
| 337 | |
| 338 // Timers. | |
| 339 elapsedTimer _cms_timer; | |
| 340 TimeStamp _gc0_begin_time; | |
| 341 TimeStamp _cms_begin_time; | |
| 342 TimeStamp _cms_end_time; | |
| 343 | |
| 344 // Snapshots of the amount used in the CMS generation. | |
| 345 size_t _cms_used_at_gc0_begin; | |
| 346 size_t _cms_used_at_gc0_end; | |
| 347 size_t _cms_used_at_cms_begin; | |
| 348 | |
| 349 // Used to prevent the duty cycle from being reduced in the middle of a cms | |
| 350 // cycle. | |
| 351 bool _allow_duty_cycle_reduction; | |
| 352 | |
| 353 enum { | |
| 354 _GC0_VALID = 0x1, | |
| 355 _CMS_VALID = 0x2, | |
| 356 _ALL_VALID = _GC0_VALID | _CMS_VALID | |
| 357 }; | |
| 358 | |
| 359 unsigned int _valid_bits; | |
| 360 | |
| 361 unsigned int _icms_duty_cycle; // icms duty cycle (0-100). | |
| 362 | |
| 363 protected: | |
| 364 | |
| 365 // Return a duty cycle that avoids wild oscillations, by limiting the amount | |
| 366 // of change between old_duty_cycle and new_duty_cycle (the latter is treated | |
| 367 // as a recommended value). | |
| 368 static unsigned int icms_damped_duty_cycle(unsigned int old_duty_cycle, | |
| 369 unsigned int new_duty_cycle); | |
| 370 unsigned int icms_update_duty_cycle_impl(); | |
| 371 | |
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372 // In support of adjusting of cms trigger ratios based on history |
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373 // of concurrent mode failure. |
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374 double cms_free_adjustment_factor(size_t free) const; |
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375 void adjust_cms_free_adjustment_factor(bool fail, size_t free); |
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376 |
| 0 | 377 public: |
| 378 CMSStats(ConcurrentMarkSweepGeneration* cms_gen, | |
| 379 unsigned int alpha = CMSExpAvgFactor); | |
| 380 | |
| 381 // Whether or not the statistics contain valid data; higher level statistics | |
| 382 // cannot be called until this returns true (they require at least one young | |
| 383 // gen and one cms cycle to have completed). | |
| 384 bool valid() const; | |
| 385 | |
| 386 // Record statistics. | |
| 387 void record_gc0_begin(); | |
| 388 void record_gc0_end(size_t cms_gen_bytes_used); | |
| 389 void record_cms_begin(); | |
| 390 void record_cms_end(); | |
| 391 | |
| 392 // Allow management of the cms timer, which must be stopped/started around | |
| 393 // yield points. | |
| 394 elapsedTimer& cms_timer() { return _cms_timer; } | |
| 395 void start_cms_timer() { _cms_timer.start(); } | |
| 396 void stop_cms_timer() { _cms_timer.stop(); } | |
| 397 | |
| 398 // Basic statistics; units are seconds or bytes. | |
| 399 double gc0_period() const { return _gc0_period; } | |
| 400 double gc0_duration() const { return _gc0_duration; } | |
| 401 size_t gc0_promoted() const { return _gc0_promoted; } | |
| 402 double cms_period() const { return _cms_period; } | |
| 403 double cms_duration() const { return _cms_duration; } | |
| 404 double cms_duration_per_mb() const { return _cms_duration_per_mb; } | |
| 405 size_t cms_allocated() const { return _cms_allocated; } | |
| 406 | |
| 407 size_t cms_used_at_gc0_end() const { return _cms_used_at_gc0_end;} | |
| 408 | |
| 409 // Seconds since the last background cms cycle began or ended. | |
| 410 double cms_time_since_begin() const; | |
| 411 double cms_time_since_end() const; | |
| 412 | |
| 413 // Higher level statistics--caller must check that valid() returns true before | |
| 414 // calling. | |
| 415 | |
| 416 // Returns bytes promoted per second of wall clock time. | |
| 417 double promotion_rate() const; | |
| 418 | |
| 419 // Returns bytes directly allocated per second of wall clock time. | |
| 420 double cms_allocation_rate() const; | |
| 421 | |
| 422 // Rate at which space in the cms generation is being consumed (sum of the | |
| 423 // above two). | |
| 424 double cms_consumption_rate() const; | |
| 425 | |
| 426 // Returns an estimate of the number of seconds until the cms generation will | |
| 427 // fill up, assuming no collection work is done. | |
| 428 double time_until_cms_gen_full() const; | |
| 429 | |
| 430 // Returns an estimate of the number of seconds remaining until | |
| 431 // the cms generation collection should start. | |
| 432 double time_until_cms_start() const; | |
| 433 | |
| 434 // End of higher level statistics. | |
| 435 | |
| 436 // Returns the cms incremental mode duty cycle, as a percentage (0-100). | |
| 437 unsigned int icms_duty_cycle() const { return _icms_duty_cycle; } | |
| 438 | |
| 439 // Update the duty cycle and return the new value. | |
| 440 unsigned int icms_update_duty_cycle(); | |
| 441 | |
| 442 // Debugging. | |
| 443 void print_on(outputStream* st) const PRODUCT_RETURN; | |
| 444 void print() const { print_on(gclog_or_tty); } | |
| 445 }; | |
| 446 | |
| 447 // A closure related to weak references processing which | |
| 448 // we embed in the CMSCollector, since we need to pass | |
| 449 // it to the reference processor for secondary filtering | |
| 450 // of references based on reachability of referent; | |
| 451 // see role of _is_alive_non_header closure in the | |
| 452 // ReferenceProcessor class. | |
| 453 // For objects in the CMS generation, this closure checks | |
| 454 // if the object is "live" (reachable). Used in weak | |
| 455 // reference processing. | |
| 456 class CMSIsAliveClosure: public BoolObjectClosure { | |
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457 const MemRegion _span; |
| 0 | 458 const CMSBitMap* _bit_map; |
| 459 | |
| 460 friend class CMSCollector; | |
| 461 public: | |
| 462 CMSIsAliveClosure(MemRegion span, | |
| 463 CMSBitMap* bit_map): | |
| 464 _span(span), | |
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465 _bit_map(bit_map) { |
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466 assert(!span.is_empty(), "Empty span could spell trouble"); |
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467 } |
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468 |
| 0 | 469 void do_object(oop obj) { |
| 470 assert(false, "not to be invoked"); | |
| 471 } | |
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472 |
| 0 | 473 bool do_object_b(oop obj); |
| 474 }; | |
| 475 | |
| 476 | |
| 477 // Implements AbstractRefProcTaskExecutor for CMS. | |
| 478 class CMSRefProcTaskExecutor: public AbstractRefProcTaskExecutor { | |
| 479 public: | |
| 480 | |
| 481 CMSRefProcTaskExecutor(CMSCollector& collector) | |
| 482 : _collector(collector) | |
| 483 { } | |
| 484 | |
| 485 // Executes a task using worker threads. | |
| 486 virtual void execute(ProcessTask& task); | |
| 487 virtual void execute(EnqueueTask& task); | |
| 488 private: | |
| 489 CMSCollector& _collector; | |
| 490 }; | |
| 491 | |
| 492 | |
| 493 class CMSCollector: public CHeapObj { | |
| 494 friend class VMStructs; | |
| 495 friend class ConcurrentMarkSweepThread; | |
| 496 friend class ConcurrentMarkSweepGeneration; | |
| 497 friend class CompactibleFreeListSpace; | |
| 498 friend class CMSParRemarkTask; | |
| 499 friend class CMSConcMarkingTask; | |
| 500 friend class CMSRefProcTaskProxy; | |
| 501 friend class CMSRefProcTaskExecutor; | |
| 502 friend class ScanMarkedObjectsAgainCarefullyClosure; // for sampling eden | |
| 503 friend class SurvivorSpacePrecleanClosure; // --- ditto ------- | |
| 504 friend class PushOrMarkClosure; // to access _restart_addr | |
| 505 friend class Par_PushOrMarkClosure; // to access _restart_addr | |
| 506 friend class MarkFromRootsClosure; // -- ditto -- | |
| 507 // ... and for clearing cards | |
| 508 friend class Par_MarkFromRootsClosure; // to access _restart_addr | |
| 509 // ... and for clearing cards | |
| 510 friend class Par_ConcMarkingClosure; // to access _restart_addr etc. | |
| 511 friend class MarkFromRootsVerifyClosure; // to access _restart_addr | |
| 512 friend class PushAndMarkVerifyClosure; // -- ditto -- | |
| 513 friend class MarkRefsIntoAndScanClosure; // to access _overflow_list | |
| 514 friend class PushAndMarkClosure; // -- ditto -- | |
| 515 friend class Par_PushAndMarkClosure; // -- ditto -- | |
| 516 friend class CMSKeepAliveClosure; // -- ditto -- | |
| 517 friend class CMSDrainMarkingStackClosure; // -- ditto -- | |
| 518 friend class CMSInnerParMarkAndPushClosure; // -- ditto -- | |
| 519 NOT_PRODUCT(friend class ScanMarkedObjectsAgainClosure;) // assertion on _overflow_list | |
| 520 friend class ReleaseForegroundGC; // to access _foregroundGCShouldWait | |
| 521 friend class VM_CMS_Operation; | |
| 522 friend class VM_CMS_Initial_Mark; | |
| 523 friend class VM_CMS_Final_Remark; | |
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524 friend class TraceCMSMemoryManagerStats; |
| 0 | 525 |
| 526 private: | |
| 527 jlong _time_of_last_gc; | |
| 528 void update_time_of_last_gc(jlong now) { | |
| 529 _time_of_last_gc = now; | |
| 530 } | |
| 531 | |
| 532 OopTaskQueueSet* _task_queues; | |
| 533 | |
| 534 // Overflow list of grey objects, threaded through mark-word | |
| 535 // Manipulated with CAS in the parallel/multi-threaded case. | |
| 536 oop _overflow_list; | |
| 537 // The following array-pair keeps track of mark words | |
| 538 // displaced for accomodating overflow list above. | |
| 539 // This code will likely be revisited under RFE#4922830. | |
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540 Stack<oop> _preserved_oop_stack; |
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541 Stack<markOop> _preserved_mark_stack; |
| 0 | 542 |
| 543 int* _hash_seed; | |
| 544 | |
| 545 // In support of multi-threaded concurrent phases | |
| 546 YieldingFlexibleWorkGang* _conc_workers; | |
| 547 | |
| 548 // Performance Counters | |
| 549 CollectorCounters* _gc_counters; | |
| 550 | |
| 551 // Initialization Errors | |
| 552 bool _completed_initialization; | |
| 553 | |
| 554 // In support of ExplicitGCInvokesConcurrent | |
| 555 static bool _full_gc_requested; | |
| 556 unsigned int _collection_count_start; | |
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557 |
| 0 | 558 // Should we unload classes this concurrent cycle? |
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559 bool _should_unload_classes; |
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560 unsigned int _concurrent_cycles_since_last_unload; |
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561 unsigned int concurrent_cycles_since_last_unload() const { |
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562 return _concurrent_cycles_since_last_unload; |
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563 } |
| 0 | 564 // Did we (allow) unload classes in the previous concurrent cycle? |
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565 bool unloaded_classes_last_cycle() const { |
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566 return concurrent_cycles_since_last_unload() == 0; |
| 0 | 567 } |
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568 // Root scanning options for perm gen |
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569 int _roots_scanning_options; |
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570 int roots_scanning_options() const { return _roots_scanning_options; } |
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571 void add_root_scanning_option(int o) { _roots_scanning_options |= o; } |
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572 void remove_root_scanning_option(int o) { _roots_scanning_options &= ~o; } |
| 0 | 573 |
| 574 // Verification support | |
| 575 CMSBitMap _verification_mark_bm; | |
| 576 void verify_after_remark_work_1(); | |
| 577 void verify_after_remark_work_2(); | |
| 578 | |
| 579 // true if any verification flag is on. | |
| 580 bool _verifying; | |
| 581 bool verifying() const { return _verifying; } | |
| 582 void set_verifying(bool v) { _verifying = v; } | |
| 583 | |
| 584 // Collector policy | |
| 585 ConcurrentMarkSweepPolicy* _collector_policy; | |
| 586 ConcurrentMarkSweepPolicy* collector_policy() { return _collector_policy; } | |
| 587 | |
| 588 // XXX Move these to CMSStats ??? FIX ME !!! | |
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589 elapsedTimer _inter_sweep_timer; // time between sweeps |
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590 elapsedTimer _intra_sweep_timer; // time _in_ sweeps |
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591 // padded decaying average estimates of the above |
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592 AdaptivePaddedAverage _inter_sweep_estimate; |
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593 AdaptivePaddedAverage _intra_sweep_estimate; |
| 0 | 594 |
| 595 protected: | |
| 596 ConcurrentMarkSweepGeneration* _cmsGen; // old gen (CMS) | |
| 597 ConcurrentMarkSweepGeneration* _permGen; // perm gen | |
| 598 MemRegion _span; // span covering above two | |
| 599 CardTableRS* _ct; // card table | |
| 600 | |
| 601 // CMS marking support structures | |
| 602 CMSBitMap _markBitMap; | |
| 603 CMSBitMap _modUnionTable; | |
| 604 CMSMarkStack _markStack; | |
| 605 CMSMarkStack _revisitStack; // used to keep track of klassKlass objects | |
| 606 // to revisit | |
| 607 CMSBitMap _perm_gen_verify_bit_map; // Mark bit map for perm gen verification support. | |
| 608 | |
| 609 HeapWord* _restart_addr; // in support of marking stack overflow | |
| 610 void lower_restart_addr(HeapWord* low); | |
| 611 | |
| 612 // Counters in support of marking stack / work queue overflow handling: | |
| 613 // a non-zero value indicates certain types of overflow events during | |
| 614 // the current CMS cycle and could lead to stack resizing efforts at | |
| 615 // an opportune future time. | |
| 616 size_t _ser_pmc_preclean_ovflw; | |
| 617 size_t _ser_pmc_remark_ovflw; | |
| 618 size_t _par_pmc_remark_ovflw; | |
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619 size_t _ser_kac_preclean_ovflw; |
| 0 | 620 size_t _ser_kac_ovflw; |
| 621 size_t _par_kac_ovflw; | |
| 534 | 622 NOT_PRODUCT(ssize_t _num_par_pushes;) |
| 0 | 623 |
| 624 // ("Weak") Reference processing support | |
| 625 ReferenceProcessor* _ref_processor; | |
| 626 CMSIsAliveClosure _is_alive_closure; | |
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627 // keep this textually after _markBitMap and _span; c'tor dependency |
| 0 | 628 |
| 629 ConcurrentMarkSweepThread* _cmsThread; // the thread doing the work | |
| 630 ModUnionClosure _modUnionClosure; | |
| 631 ModUnionClosurePar _modUnionClosurePar; | |
| 632 | |
| 633 // CMS abstract state machine | |
| 634 // initial_state: Idling | |
| 635 // next_state(Idling) = {Marking} | |
| 636 // next_state(Marking) = {Precleaning, Sweeping} | |
| 637 // next_state(Precleaning) = {AbortablePreclean, FinalMarking} | |
| 638 // next_state(AbortablePreclean) = {FinalMarking} | |
| 639 // next_state(FinalMarking) = {Sweeping} | |
| 640 // next_state(Sweeping) = {Resizing} | |
| 641 // next_state(Resizing) = {Resetting} | |
| 642 // next_state(Resetting) = {Idling} | |
| 643 // The numeric values below are chosen so that: | |
| 644 // . _collectorState <= Idling == post-sweep && pre-mark | |
| 645 // . _collectorState in (Idling, Sweeping) == {initial,final}marking || | |
| 646 // precleaning || abortablePrecleanb | |
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647 public: |
| 0 | 648 enum CollectorState { |
| 649 Resizing = 0, | |
| 650 Resetting = 1, | |
| 651 Idling = 2, | |
| 652 InitialMarking = 3, | |
| 653 Marking = 4, | |
| 654 Precleaning = 5, | |
| 655 AbortablePreclean = 6, | |
| 656 FinalMarking = 7, | |
| 657 Sweeping = 8 | |
| 658 }; | |
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659 protected: |
| 0 | 660 static CollectorState _collectorState; |
| 661 | |
| 662 // State related to prologue/epilogue invocation for my generations | |
| 663 bool _between_prologue_and_epilogue; | |
| 664 | |
| 665 // Signalling/State related to coordination between fore- and backgroud GC | |
| 666 // Note: When the baton has been passed from background GC to foreground GC, | |
| 667 // _foregroundGCIsActive is true and _foregroundGCShouldWait is false. | |
| 668 static bool _foregroundGCIsActive; // true iff foreground collector is active or | |
| 669 // wants to go active | |
| 670 static bool _foregroundGCShouldWait; // true iff background GC is active and has not | |
| 671 // yet passed the baton to the foreground GC | |
| 672 | |
| 673 // Support for CMSScheduleRemark (abortable preclean) | |
| 674 bool _abort_preclean; | |
| 675 bool _start_sampling; | |
| 676 | |
| 677 int _numYields; | |
| 678 size_t _numDirtyCards; | |
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679 size_t _sweep_count; |
| 0 | 680 // number of full gc's since the last concurrent gc. |
| 681 uint _full_gcs_since_conc_gc; | |
| 682 | |
| 683 // occupancy used for bootstrapping stats | |
| 684 double _bootstrap_occupancy; | |
| 685 | |
| 686 // timer | |
| 687 elapsedTimer _timer; | |
| 688 | |
| 689 // Timing, allocation and promotion statistics, used for scheduling. | |
| 690 CMSStats _stats; | |
| 691 | |
| 692 // Allocation limits installed in the young gen, used only in | |
| 693 // CMSIncrementalMode. When an allocation in the young gen would cross one of | |
| 694 // these limits, the cms generation is notified and the cms thread is started | |
| 695 // or stopped, respectively. | |
| 696 HeapWord* _icms_start_limit; | |
| 697 HeapWord* _icms_stop_limit; | |
| 698 | |
| 699 enum CMS_op_type { | |
| 700 CMS_op_checkpointRootsInitial, | |
| 701 CMS_op_checkpointRootsFinal | |
| 702 }; | |
| 703 | |
| 704 void do_CMS_operation(CMS_op_type op); | |
| 705 bool stop_world_and_do(CMS_op_type op); | |
| 706 | |
| 707 OopTaskQueueSet* task_queues() { return _task_queues; } | |
| 708 int* hash_seed(int i) { return &_hash_seed[i]; } | |
| 709 YieldingFlexibleWorkGang* conc_workers() { return _conc_workers; } | |
| 710 | |
| 711 // Support for parallelizing Eden rescan in CMS remark phase | |
| 712 void sample_eden(); // ... sample Eden space top | |
| 713 | |
| 714 private: | |
| 715 // Support for parallelizing young gen rescan in CMS remark phase | |
| 716 Generation* _young_gen; // the younger gen | |
| 717 HeapWord** _top_addr; // ... Top of Eden | |
| 718 HeapWord** _end_addr; // ... End of Eden | |
| 719 HeapWord** _eden_chunk_array; // ... Eden partitioning array | |
| 720 size_t _eden_chunk_index; // ... top (exclusive) of array | |
| 721 size_t _eden_chunk_capacity; // ... max entries in array | |
| 722 | |
| 723 // Support for parallelizing survivor space rescan | |
| 724 HeapWord** _survivor_chunk_array; | |
| 725 size_t _survivor_chunk_index; | |
| 726 size_t _survivor_chunk_capacity; | |
| 727 size_t* _cursor; | |
| 728 ChunkArray* _survivor_plab_array; | |
| 729 | |
| 730 // Support for marking stack overflow handling | |
| 731 bool take_from_overflow_list(size_t num, CMSMarkStack* to_stack); | |
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732 bool par_take_from_overflow_list(size_t num, |
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733 OopTaskQueue* to_work_q, |
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734 int no_of_gc_threads); |
| 0 | 735 void push_on_overflow_list(oop p); |
| 736 void par_push_on_overflow_list(oop p); | |
| 737 // the following is, obviously, not, in general, "MT-stable" | |
| 738 bool overflow_list_is_empty() const; | |
| 739 | |
| 740 void preserve_mark_if_necessary(oop p); | |
| 741 void par_preserve_mark_if_necessary(oop p); | |
| 742 void preserve_mark_work(oop p, markOop m); | |
| 743 void restore_preserved_marks_if_any(); | |
| 744 NOT_PRODUCT(bool no_preserved_marks() const;) | |
| 745 // in support of testing overflow code | |
| 746 NOT_PRODUCT(int _overflow_counter;) | |
| 747 NOT_PRODUCT(bool simulate_overflow();) // sequential | |
| 748 NOT_PRODUCT(bool par_simulate_overflow();) // MT version | |
| 749 | |
| 750 // CMS work methods | |
| 751 void checkpointRootsInitialWork(bool asynch); // initial checkpoint work | |
| 752 | |
| 753 // a return value of false indicates failure due to stack overflow | |
| 754 bool markFromRootsWork(bool asynch); // concurrent marking work | |
| 755 | |
| 756 public: // FIX ME!!! only for testing | |
| 757 bool do_marking_st(bool asynch); // single-threaded marking | |
| 758 bool do_marking_mt(bool asynch); // multi-threaded marking | |
| 759 | |
| 760 private: | |
| 761 | |
| 762 // concurrent precleaning work | |
| 763 size_t preclean_mod_union_table(ConcurrentMarkSweepGeneration* gen, | |
| 764 ScanMarkedObjectsAgainCarefullyClosure* cl); | |
| 765 size_t preclean_card_table(ConcurrentMarkSweepGeneration* gen, | |
| 766 ScanMarkedObjectsAgainCarefullyClosure* cl); | |
| 767 // Does precleaning work, returning a quantity indicative of | |
| 768 // the amount of "useful work" done. | |
| 769 size_t preclean_work(bool clean_refs, bool clean_survivors); | |
| 770 void abortable_preclean(); // Preclean while looking for possible abort | |
| 771 void initialize_sequential_subtasks_for_young_gen_rescan(int i); | |
| 772 // Helper function for above; merge-sorts the per-thread plab samples | |
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773 void merge_survivor_plab_arrays(ContiguousSpace* surv, int no_of_gc_threads); |
| 0 | 774 // Resets (i.e. clears) the per-thread plab sample vectors |
| 775 void reset_survivor_plab_arrays(); | |
| 776 | |
| 777 // final (second) checkpoint work | |
| 778 void checkpointRootsFinalWork(bool asynch, bool clear_all_soft_refs, | |
| 779 bool init_mark_was_synchronous); | |
| 780 // work routine for parallel version of remark | |
| 781 void do_remark_parallel(); | |
| 782 // work routine for non-parallel version of remark | |
| 783 void do_remark_non_parallel(); | |
| 784 // reference processing work routine (during second checkpoint) | |
| 785 void refProcessingWork(bool asynch, bool clear_all_soft_refs); | |
| 786 | |
| 787 // concurrent sweeping work | |
| 788 void sweepWork(ConcurrentMarkSweepGeneration* gen, bool asynch); | |
| 789 | |
| 790 // (concurrent) resetting of support data structures | |
| 791 void reset(bool asynch); | |
| 792 | |
| 793 // Clear _expansion_cause fields of constituent generations | |
| 794 void clear_expansion_cause(); | |
| 795 | |
| 796 // An auxilliary method used to record the ends of | |
| 797 // used regions of each generation to limit the extent of sweep | |
| 798 void save_sweep_limits(); | |
| 799 | |
| 800 // Resize the generations included in the collector. | |
| 801 void compute_new_size(); | |
| 802 | |
| 803 // A work method used by foreground collection to determine | |
| 804 // what type of collection (compacting or not, continuing or fresh) | |
| 805 // it should do. | |
| 806 void decide_foreground_collection_type(bool clear_all_soft_refs, | |
| 807 bool* should_compact, bool* should_start_over); | |
| 808 | |
| 809 // A work method used by the foreground collector to do | |
| 810 // a mark-sweep-compact. | |
| 811 void do_compaction_work(bool clear_all_soft_refs); | |
| 812 | |
| 813 // A work method used by the foreground collector to do | |
| 814 // a mark-sweep, after taking over from a possibly on-going | |
| 815 // concurrent mark-sweep collection. | |
| 816 void do_mark_sweep_work(bool clear_all_soft_refs, | |
| 817 CollectorState first_state, bool should_start_over); | |
| 818 | |
| 819 // If the backgrould GC is active, acquire control from the background | |
| 820 // GC and do the collection. | |
| 821 void acquire_control_and_collect(bool full, bool clear_all_soft_refs); | |
| 822 | |
| 823 // For synchronizing passing of control from background to foreground | |
| 824 // GC. waitForForegroundGC() is called by the background | |
| 825 // collector. It if had to wait for a foreground collection, | |
| 826 // it returns true and the background collection should assume | |
| 827 // that the collection was finished by the foreground | |
| 828 // collector. | |
| 829 bool waitForForegroundGC(); | |
| 830 | |
| 831 // Incremental mode triggering: recompute the icms duty cycle and set the | |
| 832 // allocation limits in the young gen. | |
| 833 void icms_update_allocation_limits(); | |
| 834 | |
| 835 size_t block_size_using_printezis_bits(HeapWord* addr) const; | |
| 836 size_t block_size_if_printezis_bits(HeapWord* addr) const; | |
| 837 HeapWord* next_card_start_after_block(HeapWord* addr) const; | |
| 838 | |
| 839 void setup_cms_unloading_and_verification_state(); | |
| 840 public: | |
| 841 CMSCollector(ConcurrentMarkSweepGeneration* cmsGen, | |
| 842 ConcurrentMarkSweepGeneration* permGen, | |
| 843 CardTableRS* ct, | |
| 844 ConcurrentMarkSweepPolicy* cp); | |
| 845 ConcurrentMarkSweepThread* cmsThread() { return _cmsThread; } | |
| 846 | |
| 847 ReferenceProcessor* ref_processor() { return _ref_processor; } | |
| 848 void ref_processor_init(); | |
| 849 | |
| 850 Mutex* bitMapLock() const { return _markBitMap.lock(); } | |
| 851 static CollectorState abstract_state() { return _collectorState; } | |
| 852 | |
| 853 bool should_abort_preclean() const; // Whether preclean should be aborted. | |
| 854 size_t get_eden_used() const; | |
| 855 size_t get_eden_capacity() const; | |
| 856 | |
| 857 ConcurrentMarkSweepGeneration* cmsGen() { return _cmsGen; } | |
| 858 | |
| 859 // locking checks | |
| 860 NOT_PRODUCT(static bool have_cms_token();) | |
| 861 | |
| 862 // XXXPERM bool should_collect(bool full, size_t size, bool tlab); | |
| 863 bool shouldConcurrentCollect(); | |
| 864 | |
| 865 void collect(bool full, | |
| 866 bool clear_all_soft_refs, | |
| 867 size_t size, | |
| 868 bool tlab); | |
| 869 void collect_in_background(bool clear_all_soft_refs); | |
| 870 void collect_in_foreground(bool clear_all_soft_refs); | |
| 871 | |
| 872 // In support of ExplicitGCInvokesConcurrent | |
| 873 static void request_full_gc(unsigned int full_gc_count); | |
| 874 // Should we unload classes in a particular concurrent cycle? | |
|
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875 bool should_unload_classes() const { |
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876 return _should_unload_classes; |
| 0 | 877 } |
|
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878 bool update_should_unload_classes(); |
| 0 | 879 |
| 880 void direct_allocated(HeapWord* start, size_t size); | |
| 881 | |
| 882 // Object is dead if not marked and current phase is sweeping. | |
| 883 bool is_dead_obj(oop obj) const; | |
| 884 | |
| 885 // After a promotion (of "start"), do any necessary marking. | |
| 886 // If "par", then it's being done by a parallel GC thread. | |
| 887 // The last two args indicate if we need precise marking | |
| 888 // and if so the size of the object so it can be dirtied | |
| 889 // in its entirety. | |
| 890 void promoted(bool par, HeapWord* start, | |
| 891 bool is_obj_array, size_t obj_size); | |
| 892 | |
| 893 HeapWord* allocation_limit_reached(Space* space, HeapWord* top, | |
| 894 size_t word_size); | |
| 895 | |
| 896 void getFreelistLocks() const; | |
| 897 void releaseFreelistLocks() const; | |
| 898 bool haveFreelistLocks() const; | |
| 899 | |
| 900 // GC prologue and epilogue | |
| 901 void gc_prologue(bool full); | |
| 902 void gc_epilogue(bool full); | |
| 903 | |
| 904 jlong time_of_last_gc(jlong now) { | |
| 905 if (_collectorState <= Idling) { | |
| 906 // gc not in progress | |
| 907 return _time_of_last_gc; | |
| 908 } else { | |
| 909 // collection in progress | |
| 910 return now; | |
| 911 } | |
| 912 } | |
| 913 | |
| 914 // Support for parallel remark of survivor space | |
| 915 void* get_data_recorder(int thr_num); | |
| 916 | |
| 917 CMSBitMap* markBitMap() { return &_markBitMap; } | |
| 918 void directAllocated(HeapWord* start, size_t size); | |
| 919 | |
| 920 // main CMS steps and related support | |
| 921 void checkpointRootsInitial(bool asynch); | |
| 922 bool markFromRoots(bool asynch); // a return value of false indicates failure | |
| 923 // due to stack overflow | |
| 924 void preclean(); | |
| 925 void checkpointRootsFinal(bool asynch, bool clear_all_soft_refs, | |
| 926 bool init_mark_was_synchronous); | |
| 927 void sweep(bool asynch); | |
| 928 | |
| 929 // Check that the currently executing thread is the expected | |
| 930 // one (foreground collector or background collector). | |
|
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931 static void check_correct_thread_executing() PRODUCT_RETURN; |
| 0 | 932 // XXXPERM void print_statistics() PRODUCT_RETURN; |
| 933 | |
| 934 bool is_cms_reachable(HeapWord* addr); | |
| 935 | |
| 936 // Performance Counter Support | |
| 937 CollectorCounters* counters() { return _gc_counters; } | |
| 938 | |
| 939 // timer stuff | |
| 940 void startTimer() { assert(!_timer.is_active(), "Error"); _timer.start(); } | |
| 941 void stopTimer() { assert( _timer.is_active(), "Error"); _timer.stop(); } | |
| 942 void resetTimer() { assert(!_timer.is_active(), "Error"); _timer.reset(); } | |
| 943 double timerValue() { assert(!_timer.is_active(), "Error"); return _timer.seconds(); } | |
| 944 | |
| 945 int yields() { return _numYields; } | |
| 946 void resetYields() { _numYields = 0; } | |
| 947 void incrementYields() { _numYields++; } | |
| 948 void resetNumDirtyCards() { _numDirtyCards = 0; } | |
| 949 void incrementNumDirtyCards(size_t num) { _numDirtyCards += num; } | |
| 950 size_t numDirtyCards() { return _numDirtyCards; } | |
| 951 | |
| 952 static bool foregroundGCShouldWait() { return _foregroundGCShouldWait; } | |
| 953 static void set_foregroundGCShouldWait(bool v) { _foregroundGCShouldWait = v; } | |
| 954 static bool foregroundGCIsActive() { return _foregroundGCIsActive; } | |
| 955 static void set_foregroundGCIsActive(bool v) { _foregroundGCIsActive = v; } | |
|
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956 size_t sweep_count() const { return _sweep_count; } |
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957 void increment_sweep_count() { _sweep_count++; } |
| 0 | 958 |
| 959 // Timers/stats for gc scheduling and incremental mode pacing. | |
| 960 CMSStats& stats() { return _stats; } | |
| 961 | |
| 962 // Convenience methods that check whether CMSIncrementalMode is enabled and | |
| 963 // forward to the corresponding methods in ConcurrentMarkSweepThread. | |
| 964 static void start_icms(); | |
| 965 static void stop_icms(); // Called at the end of the cms cycle. | |
| 966 static void disable_icms(); // Called before a foreground collection. | |
| 967 static void enable_icms(); // Called after a foreground collection. | |
| 968 void icms_wait(); // Called at yield points. | |
| 969 | |
| 970 // Adaptive size policy | |
| 971 CMSAdaptiveSizePolicy* size_policy(); | |
| 972 CMSGCAdaptivePolicyCounters* gc_adaptive_policy_counters(); | |
| 973 | |
| 974 // debugging | |
| 975 void verify(bool); | |
| 976 bool verify_after_remark(); | |
| 977 void verify_ok_to_terminate() const PRODUCT_RETURN; | |
| 978 void verify_work_stacks_empty() const PRODUCT_RETURN; | |
| 979 void verify_overflow_empty() const PRODUCT_RETURN; | |
| 980 | |
| 981 // convenience methods in support of debugging | |
| 982 static const size_t skip_header_HeapWords() PRODUCT_RETURN0; | |
| 983 HeapWord* block_start(const void* p) const PRODUCT_RETURN0; | |
| 984 | |
| 985 // accessors | |
| 986 CMSMarkStack* verification_mark_stack() { return &_markStack; } | |
| 987 CMSBitMap* verification_mark_bm() { return &_verification_mark_bm; } | |
| 988 | |
| 989 // Get the bit map with a perm gen "deadness" information. | |
| 990 CMSBitMap* perm_gen_verify_bit_map() { return &_perm_gen_verify_bit_map; } | |
| 991 | |
| 992 // Initialization errors | |
| 993 bool completed_initialization() { return _completed_initialization; } | |
| 994 }; | |
| 995 | |
| 996 class CMSExpansionCause : public AllStatic { | |
| 997 public: | |
| 998 enum Cause { | |
| 999 _no_expansion, | |
| 1000 _satisfy_free_ratio, | |
| 1001 _satisfy_promotion, | |
| 1002 _satisfy_allocation, | |
| 1003 _allocate_par_lab, | |
| 1004 _allocate_par_spooling_space, | |
| 1005 _adaptive_size_policy | |
| 1006 }; | |
| 1007 // Return a string describing the cause of the expansion. | |
| 1008 static const char* to_string(CMSExpansionCause::Cause cause); | |
| 1009 }; | |
| 1010 | |
| 1011 class ConcurrentMarkSweepGeneration: public CardGeneration { | |
| 1012 friend class VMStructs; | |
| 1013 friend class ConcurrentMarkSweepThread; | |
| 1014 friend class ConcurrentMarkSweep; | |
| 1015 friend class CMSCollector; | |
| 1016 protected: | |
| 1017 static CMSCollector* _collector; // the collector that collects us | |
| 1018 CompactibleFreeListSpace* _cmsSpace; // underlying space (only one for now) | |
| 1019 | |
| 1020 // Performance Counters | |
| 1021 GenerationCounters* _gen_counters; | |
| 1022 GSpaceCounters* _space_counters; | |
| 1023 | |
| 1024 // Words directly allocated, used by CMSStats. | |
| 1025 size_t _direct_allocated_words; | |
| 1026 | |
| 1027 // Non-product stat counters | |
| 1028 NOT_PRODUCT( | |
|
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1029 size_t _numObjectsPromoted; |
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1030 size_t _numWordsPromoted; |
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1031 size_t _numObjectsAllocated; |
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1032 size_t _numWordsAllocated; |
| 0 | 1033 ) |
| 1034 | |
| 1035 // Used for sizing decisions | |
| 1036 bool _incremental_collection_failed; | |
| 1037 bool incremental_collection_failed() { | |
| 1038 return _incremental_collection_failed; | |
| 1039 } | |
| 1040 void set_incremental_collection_failed() { | |
| 1041 _incremental_collection_failed = true; | |
| 1042 } | |
| 1043 void clear_incremental_collection_failed() { | |
| 1044 _incremental_collection_failed = false; | |
| 1045 } | |
| 1046 | |
|
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1047 // accessors |
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1048 void set_expansion_cause(CMSExpansionCause::Cause v) { _expansion_cause = v;} |
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1049 CMSExpansionCause::Cause expansion_cause() const { return _expansion_cause; } |
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1050 |
| 0 | 1051 private: |
| 1052 // For parallel young-gen GC support. | |
| 1053 CMSParGCThreadState** _par_gc_thread_states; | |
| 1054 | |
| 1055 // Reason generation was expanded | |
| 1056 CMSExpansionCause::Cause _expansion_cause; | |
| 1057 | |
| 1058 // In support of MinChunkSize being larger than min object size | |
| 1059 const double _dilatation_factor; | |
| 1060 | |
| 1061 enum CollectionTypes { | |
| 1062 Concurrent_collection_type = 0, | |
| 1063 MS_foreground_collection_type = 1, | |
| 1064 MSC_foreground_collection_type = 2, | |
| 1065 Unknown_collection_type = 3 | |
| 1066 }; | |
| 1067 | |
| 1068 CollectionTypes _debug_collection_type; | |
| 1069 | |
|
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1070 // Fraction of current occupancy at which to start a CMS collection which |
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1071 // will collect this generation (at least). |
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1072 double _initiating_occupancy; |
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1073 |
| 0 | 1074 protected: |
| 1075 // Shrink generation by specified size (returns false if unable to shrink) | |
| 1076 virtual void shrink_by(size_t bytes); | |
| 1077 | |
| 1078 // Update statistics for GC | |
| 1079 virtual void update_gc_stats(int level, bool full); | |
| 1080 | |
| 1081 // Maximum available space in the generation (including uncommitted) | |
| 1082 // space. | |
| 1083 size_t max_available() const; | |
| 1084 | |
|
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1085 // getter and initializer for _initiating_occupancy field. |
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1086 double initiating_occupancy() const { return _initiating_occupancy; } |
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1087 void init_initiating_occupancy(intx io, intx tr); |
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1088 |
| 0 | 1089 public: |
| 1090 ConcurrentMarkSweepGeneration(ReservedSpace rs, size_t initial_byte_size, | |
| 1091 int level, CardTableRS* ct, | |
| 1092 bool use_adaptive_freelists, | |
| 1093 FreeBlockDictionary::DictionaryChoice); | |
| 1094 | |
| 1095 // Accessors | |
| 1096 CMSCollector* collector() const { return _collector; } | |
| 1097 static void set_collector(CMSCollector* collector) { | |
| 1098 assert(_collector == NULL, "already set"); | |
| 1099 _collector = collector; | |
| 1100 } | |
| 1101 CompactibleFreeListSpace* cmsSpace() const { return _cmsSpace; } | |
| 1102 | |
| 1103 Mutex* freelistLock() const; | |
| 1104 | |
| 1105 virtual Generation::Name kind() { return Generation::ConcurrentMarkSweep; } | |
| 1106 | |
| 1107 // Adaptive size policy | |
| 1108 CMSAdaptiveSizePolicy* size_policy(); | |
| 1109 | |
| 1110 bool refs_discovery_is_atomic() const { return false; } | |
| 1111 bool refs_discovery_is_mt() const { | |
| 1112 // Note: CMS does MT-discovery during the parallel-remark | |
| 1113 // phases. Use ReferenceProcessorMTMutator to make refs | |
| 1114 // discovery MT-safe during such phases or other parallel | |
| 1115 // discovery phases in the future. This may all go away | |
| 1116 // if/when we decide that refs discovery is sufficiently | |
| 1117 // rare that the cost of the CAS's involved is in the | |
| 1118 // noise. That's a measurement that should be done, and | |
| 1119 // the code simplified if that turns out to be the case. | |
| 1120 return false; | |
| 1121 } | |
| 1122 | |
| 1123 // Override | |
| 1124 virtual void ref_processor_init(); | |
| 1125 | |
|
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1126 // Grow generation by specified size (returns false if unable to grow) |
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1127 bool grow_by(size_t bytes); |
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1128 // Grow generation to reserved size. |
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1129 bool grow_to_reserved(); |
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1130 |
| 0 | 1131 void clear_expansion_cause() { _expansion_cause = CMSExpansionCause::_no_expansion; } |
| 1132 | |
| 1133 // Space enquiries | |
| 1134 size_t capacity() const; | |
| 1135 size_t used() const; | |
| 1136 size_t free() const; | |
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1137 double occupancy() const { return ((double)used())/((double)capacity()); } |
| 0 | 1138 size_t contiguous_available() const; |
| 1139 size_t unsafe_max_alloc_nogc() const; | |
| 1140 | |
| 1141 // over-rides | |
| 1142 MemRegion used_region() const; | |
| 1143 MemRegion used_region_at_save_marks() const; | |
| 1144 | |
| 1145 // Does a "full" (forced) collection invoked on this generation collect | |
| 1146 // all younger generations as well? Note that the second conjunct is a | |
| 1147 // hack to allow the collection of the younger gen first if the flag is | |
| 1148 // set. This is better than using th policy's should_collect_gen0_first() | |
| 1149 // since that causes us to do an extra unnecessary pair of restart-&-stop-world. | |
| 1150 virtual bool full_collects_younger_generations() const { | |
| 1151 return UseCMSCompactAtFullCollection && !CollectGen0First; | |
| 1152 } | |
| 1153 | |
| 1154 void space_iterate(SpaceClosure* blk, bool usedOnly = false); | |
| 1155 | |
| 1156 // Support for compaction | |
| 1157 CompactibleSpace* first_compaction_space() const; | |
| 1158 // Adjust quantites in the generation affected by | |
| 1159 // the compaction. | |
| 1160 void reset_after_compaction(); | |
| 1161 | |
| 1162 // Allocation support | |
| 1163 HeapWord* allocate(size_t size, bool tlab); | |
| 1164 HeapWord* have_lock_and_allocate(size_t size, bool tlab); | |
|
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1165 oop promote(oop obj, size_t obj_size); |
| 0 | 1166 HeapWord* par_allocate(size_t size, bool tlab) { |
| 1167 return allocate(size, tlab); | |
| 1168 } | |
| 1169 | |
| 1170 // Incremental mode triggering. | |
| 1171 HeapWord* allocation_limit_reached(Space* space, HeapWord* top, | |
| 1172 size_t word_size); | |
| 1173 | |
| 1174 // Used by CMSStats to track direct allocation. The value is sampled and | |
| 1175 // reset after each young gen collection. | |
| 1176 size_t direct_allocated_words() const { return _direct_allocated_words; } | |
| 1177 void reset_direct_allocated_words() { _direct_allocated_words = 0; } | |
| 1178 | |
| 1179 // Overrides for parallel promotion. | |
| 1180 virtual oop par_promote(int thread_num, | |
| 1181 oop obj, markOop m, size_t word_sz); | |
| 1182 // This one should not be called for CMS. | |
| 1183 virtual void par_promote_alloc_undo(int thread_num, | |
| 1184 HeapWord* obj, size_t word_sz); | |
| 1185 virtual void par_promote_alloc_done(int thread_num); | |
| 1186 virtual void par_oop_since_save_marks_iterate_done(int thread_num); | |
| 1187 | |
| 1188 virtual bool promotion_attempt_is_safe(size_t promotion_in_bytes, | |
| 1189 bool younger_handles_promotion_failure) const; | |
| 1190 | |
|
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1191 // Inform this (non-young) generation that a promotion failure was |
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1192 // encountered during a collection of a younger generation that |
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1193 // promotes into this generation. |
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1194 virtual void promotion_failure_occurred(); |
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1195 |
| 0 | 1196 bool should_collect(bool full, size_t size, bool tlab); |
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1197 virtual bool should_concurrent_collect() const; |
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1198 virtual bool is_too_full() const; |
| 0 | 1199 void collect(bool full, |
| 1200 bool clear_all_soft_refs, | |
| 1201 size_t size, | |
| 1202 bool tlab); | |
| 1203 | |
| 1204 HeapWord* expand_and_allocate(size_t word_size, | |
| 1205 bool tlab, | |
| 1206 bool parallel = false); | |
| 1207 | |
| 1208 // GC prologue and epilogue | |
| 1209 void gc_prologue(bool full); | |
| 1210 void gc_prologue_work(bool full, bool registerClosure, | |
| 1211 ModUnionClosure* modUnionClosure); | |
| 1212 void gc_epilogue(bool full); | |
| 1213 void gc_epilogue_work(bool full); | |
| 1214 | |
| 1215 // Time since last GC of this generation | |
| 1216 jlong time_of_last_gc(jlong now) { | |
| 1217 return collector()->time_of_last_gc(now); | |
| 1218 } | |
| 1219 void update_time_of_last_gc(jlong now) { | |
| 1220 collector()-> update_time_of_last_gc(now); | |
| 1221 } | |
| 1222 | |
| 1223 // Allocation failure | |
| 1224 void expand(size_t bytes, size_t expand_bytes, | |
| 1225 CMSExpansionCause::Cause cause); | |
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1226 virtual bool expand(size_t bytes, size_t expand_bytes); |
| 0 | 1227 void shrink(size_t bytes); |
| 1228 HeapWord* expand_and_par_lab_allocate(CMSParGCThreadState* ps, size_t word_sz); | |
| 1229 bool expand_and_ensure_spooling_space(PromotionInfo* promo); | |
| 1230 | |
| 1231 // Iteration support and related enquiries | |
| 1232 void save_marks(); | |
| 1233 bool no_allocs_since_save_marks(); | |
| 1234 void object_iterate_since_last_GC(ObjectClosure* cl); | |
| 1235 void younger_refs_iterate(OopsInGenClosure* cl); | |
| 1236 | |
| 1237 // Iteration support specific to CMS generations | |
| 1238 void save_sweep_limit(); | |
| 1239 | |
| 1240 // More iteration support | |
| 1241 virtual void oop_iterate(MemRegion mr, OopClosure* cl); | |
| 1242 virtual void oop_iterate(OopClosure* cl); | |
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1243 virtual void safe_object_iterate(ObjectClosure* cl); |
| 0 | 1244 virtual void object_iterate(ObjectClosure* cl); |
| 1245 | |
| 1246 // Need to declare the full complement of closures, whether we'll | |
| 1247 // override them or not, or get message from the compiler: | |
| 1248 // oop_since_save_marks_iterate_nv hides virtual function... | |
| 1249 #define CMS_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ | |
| 1250 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl); | |
| 1251 ALL_SINCE_SAVE_MARKS_CLOSURES(CMS_SINCE_SAVE_MARKS_DECL) | |
| 1252 | |
| 1253 // Smart allocation XXX -- move to CFLSpace? | |
| 1254 void setNearLargestChunk(); | |
| 1255 bool isNearLargestChunk(HeapWord* addr); | |
| 1256 | |
| 1257 // Get the chunk at the end of the space. Delagates to | |
| 1258 // the space. | |
| 1259 FreeChunk* find_chunk_at_end(); | |
| 1260 | |
| 1261 // Overriding of unused functionality (sharing not yet supported with CMS) | |
| 1262 void pre_adjust_pointers(); | |
| 1263 void post_compact(); | |
| 1264 | |
| 1265 // Debugging | |
| 1266 void prepare_for_verify(); | |
| 1267 void verify(bool allow_dirty); | |
| 1268 void print_statistics() PRODUCT_RETURN; | |
| 1269 | |
| 1270 // Performance Counters support | |
| 1271 virtual void update_counters(); | |
| 1272 virtual void update_counters(size_t used); | |
| 1273 void initialize_performance_counters(); | |
| 1274 CollectorCounters* counters() { return collector()->counters(); } | |
| 1275 | |
| 1276 // Support for parallel remark of survivor space | |
| 1277 void* get_data_recorder(int thr_num) { | |
| 1278 //Delegate to collector | |
| 1279 return collector()->get_data_recorder(thr_num); | |
| 1280 } | |
| 1281 | |
| 1282 // Printing | |
| 1283 const char* name() const; | |
| 1284 virtual const char* short_name() const { return "CMS"; } | |
| 1285 void print() const; | |
| 1286 void printOccupancy(const char* s); | |
| 1287 bool must_be_youngest() const { return false; } | |
| 1288 bool must_be_oldest() const { return true; } | |
| 1289 | |
| 1290 void compute_new_size(); | |
| 1291 | |
| 1292 CollectionTypes debug_collection_type() { return _debug_collection_type; } | |
| 1293 void rotate_debug_collection_type(); | |
| 1294 }; | |
| 1295 | |
| 1296 class ASConcurrentMarkSweepGeneration : public ConcurrentMarkSweepGeneration { | |
| 1297 | |
| 1298 // Return the size policy from the heap's collector | |
| 1299 // policy casted to CMSAdaptiveSizePolicy*. | |
| 1300 CMSAdaptiveSizePolicy* cms_size_policy() const; | |
| 1301 | |
| 1302 // Resize the generation based on the adaptive size | |
| 1303 // policy. | |
| 1304 void resize(size_t cur_promo, size_t desired_promo); | |
| 1305 | |
| 1306 // Return the GC counters from the collector policy | |
| 1307 CMSGCAdaptivePolicyCounters* gc_adaptive_policy_counters(); | |
| 1308 | |
| 1309 virtual void shrink_by(size_t bytes); | |
| 1310 | |
| 1311 public: | |
| 1312 virtual void compute_new_size(); | |
| 1313 ASConcurrentMarkSweepGeneration(ReservedSpace rs, size_t initial_byte_size, | |
| 1314 int level, CardTableRS* ct, | |
| 1315 bool use_adaptive_freelists, | |
| 1316 FreeBlockDictionary::DictionaryChoice | |
| 1317 dictionaryChoice) : | |
| 1318 ConcurrentMarkSweepGeneration(rs, initial_byte_size, level, ct, | |
| 1319 use_adaptive_freelists, dictionaryChoice) {} | |
| 1320 | |
| 1321 virtual const char* short_name() const { return "ASCMS"; } | |
| 1322 virtual Generation::Name kind() { return Generation::ASConcurrentMarkSweep; } | |
| 1323 | |
| 1324 virtual void update_counters(); | |
| 1325 virtual void update_counters(size_t used); | |
| 1326 }; | |
| 1327 | |
| 1328 // | |
| 1329 // Closures of various sorts used by CMS to accomplish its work | |
| 1330 // | |
| 1331 | |
| 1332 // This closure is used to check that a certain set of oops is empty. | |
| 1333 class FalseClosure: public OopClosure { | |
| 1334 public: | |
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1335 void do_oop(oop* p) { guarantee(false, "Should be an empty set"); } |
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1336 void do_oop(narrowOop* p) { guarantee(false, "Should be an empty set"); } |
| 0 | 1337 }; |
| 1338 | |
| 1339 // This closure is used to do concurrent marking from the roots | |
| 1340 // following the first checkpoint. | |
| 1341 class MarkFromRootsClosure: public BitMapClosure { | |
| 1342 CMSCollector* _collector; | |
| 1343 MemRegion _span; | |
| 1344 CMSBitMap* _bitMap; | |
| 1345 CMSBitMap* _mut; | |
| 1346 CMSMarkStack* _markStack; | |
| 1347 CMSMarkStack* _revisitStack; | |
| 1348 bool _yield; | |
| 1349 int _skipBits; | |
| 1350 HeapWord* _finger; | |
| 1351 HeapWord* _threshold; | |
| 1352 DEBUG_ONLY(bool _verifying;) | |
| 1353 | |
| 1354 public: | |
| 1355 MarkFromRootsClosure(CMSCollector* collector, MemRegion span, | |
| 1356 CMSBitMap* bitMap, | |
| 1357 CMSMarkStack* markStack, | |
| 1358 CMSMarkStack* revisitStack, | |
| 1359 bool should_yield, bool verifying = false); | |
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1360 bool do_bit(size_t offset); |
| 0 | 1361 void reset(HeapWord* addr); |
| 1362 inline void do_yield_check(); | |
| 1363 | |
| 1364 private: | |
| 1365 void scanOopsInOop(HeapWord* ptr); | |
| 1366 void do_yield_work(); | |
| 1367 }; | |
| 1368 | |
| 1369 // This closure is used to do concurrent multi-threaded | |
| 1370 // marking from the roots following the first checkpoint. | |
| 1371 // XXX This should really be a subclass of The serial version | |
| 1372 // above, but i have not had the time to refactor things cleanly. | |
| 1373 // That willbe done for Dolphin. | |
| 1374 class Par_MarkFromRootsClosure: public BitMapClosure { | |
| 1375 CMSCollector* _collector; | |
| 1376 MemRegion _whole_span; | |
| 1377 MemRegion _span; | |
| 1378 CMSBitMap* _bit_map; | |
| 1379 CMSBitMap* _mut; | |
| 1380 OopTaskQueue* _work_queue; | |
| 1381 CMSMarkStack* _overflow_stack; | |
| 1382 CMSMarkStack* _revisit_stack; | |
| 1383 bool _yield; | |
| 1384 int _skip_bits; | |
| 1385 HeapWord* _finger; | |
| 1386 HeapWord* _threshold; | |
| 1387 CMSConcMarkingTask* _task; | |
| 1388 public: | |
| 1389 Par_MarkFromRootsClosure(CMSConcMarkingTask* task, CMSCollector* collector, | |
| 1390 MemRegion span, | |
| 1391 CMSBitMap* bit_map, | |
| 1392 OopTaskQueue* work_queue, | |
| 1393 CMSMarkStack* overflow_stack, | |
| 1394 CMSMarkStack* revisit_stack, | |
| 1395 bool should_yield); | |
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1396 bool do_bit(size_t offset); |
| 0 | 1397 inline void do_yield_check(); |
| 1398 | |
| 1399 private: | |
| 1400 void scan_oops_in_oop(HeapWord* ptr); | |
| 1401 void do_yield_work(); | |
| 1402 bool get_work_from_overflow_stack(); | |
| 1403 }; | |
| 1404 | |
| 1405 // The following closures are used to do certain kinds of verification of | |
| 1406 // CMS marking. | |
| 1407 class PushAndMarkVerifyClosure: public OopClosure { | |
| 1408 CMSCollector* _collector; | |
| 1409 MemRegion _span; | |
| 1410 CMSBitMap* _verification_bm; | |
| 1411 CMSBitMap* _cms_bm; | |
| 1412 CMSMarkStack* _mark_stack; | |
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1413 protected: |
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1414 void do_oop(oop p); |
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1415 template <class T> inline void do_oop_work(T *p) { |
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1416 oop obj = oopDesc::load_decode_heap_oop_not_null(p); |
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1417 do_oop(obj); |
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1418 } |
| 0 | 1419 public: |
| 1420 PushAndMarkVerifyClosure(CMSCollector* cms_collector, | |
| 1421 MemRegion span, | |
| 1422 CMSBitMap* verification_bm, | |
| 1423 CMSBitMap* cms_bm, | |
| 1424 CMSMarkStack* mark_stack); | |
| 1425 void do_oop(oop* p); | |
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1426 void do_oop(narrowOop* p); |
| 0 | 1427 // Deal with a stack overflow condition |
| 1428 void handle_stack_overflow(HeapWord* lost); | |
| 1429 }; | |
| 1430 | |
| 1431 class MarkFromRootsVerifyClosure: public BitMapClosure { | |
| 1432 CMSCollector* _collector; | |
| 1433 MemRegion _span; | |
| 1434 CMSBitMap* _verification_bm; | |
| 1435 CMSBitMap* _cms_bm; | |
| 1436 CMSMarkStack* _mark_stack; | |
| 1437 HeapWord* _finger; | |
| 1438 PushAndMarkVerifyClosure _pam_verify_closure; | |
| 1439 public: | |
| 1440 MarkFromRootsVerifyClosure(CMSCollector* collector, MemRegion span, | |
| 1441 CMSBitMap* verification_bm, | |
| 1442 CMSBitMap* cms_bm, | |
| 1443 CMSMarkStack* mark_stack); | |
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1444 bool do_bit(size_t offset); |
| 0 | 1445 void reset(HeapWord* addr); |
| 1446 }; | |
| 1447 | |
| 1448 | |
| 1449 // This closure is used to check that a certain set of bits is | |
| 1450 // "empty" (i.e. the bit vector doesn't have any 1-bits). | |
| 1451 class FalseBitMapClosure: public BitMapClosure { | |
| 1452 public: | |
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1453 bool do_bit(size_t offset) { |
| 0 | 1454 guarantee(false, "Should not have a 1 bit"); |
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1455 return true; |
| 0 | 1456 } |
| 1457 }; | |
| 1458 | |
| 1459 // This closure is used during the second checkpointing phase | |
| 1460 // to rescan the marked objects on the dirty cards in the mod | |
| 1461 // union table and the card table proper. It's invoked via | |
| 1462 // MarkFromDirtyCardsClosure below. It uses either | |
| 1463 // [Par_]MarkRefsIntoAndScanClosure (Par_ in the parallel case) | |
| 1464 // declared in genOopClosures.hpp to accomplish some of its work. | |
| 1465 // In the parallel case the bitMap is shared, so access to | |
| 1466 // it needs to be suitably synchronized for updates by embedded | |
| 1467 // closures that update it; however, this closure itself only | |
| 1468 // reads the bit_map and because it is idempotent, is immune to | |
| 1469 // reading stale values. | |
| 1470 class ScanMarkedObjectsAgainClosure: public UpwardsObjectClosure { | |
| 1471 #ifdef ASSERT | |
| 1472 CMSCollector* _collector; | |
| 1473 MemRegion _span; | |
| 1474 union { | |
| 1475 CMSMarkStack* _mark_stack; | |
| 1476 OopTaskQueue* _work_queue; | |
| 1477 }; | |
| 1478 #endif // ASSERT | |
| 1479 bool _parallel; | |
| 1480 CMSBitMap* _bit_map; | |
| 1481 union { | |
| 1482 MarkRefsIntoAndScanClosure* _scan_closure; | |
| 1483 Par_MarkRefsIntoAndScanClosure* _par_scan_closure; | |
| 1484 }; | |
| 1485 | |
| 1486 public: | |
| 1487 ScanMarkedObjectsAgainClosure(CMSCollector* collector, | |
| 1488 MemRegion span, | |
| 1489 ReferenceProcessor* rp, | |
| 1490 CMSBitMap* bit_map, | |
| 1491 CMSMarkStack* mark_stack, | |
| 1492 CMSMarkStack* revisit_stack, | |
| 1493 MarkRefsIntoAndScanClosure* cl): | |
| 1494 #ifdef ASSERT | |
| 1495 _collector(collector), | |
| 1496 _span(span), | |
| 1497 _mark_stack(mark_stack), | |
| 1498 #endif // ASSERT | |
| 1499 _parallel(false), | |
| 1500 _bit_map(bit_map), | |
| 1501 _scan_closure(cl) { } | |
| 1502 | |
| 1503 ScanMarkedObjectsAgainClosure(CMSCollector* collector, | |
| 1504 MemRegion span, | |
| 1505 ReferenceProcessor* rp, | |
| 1506 CMSBitMap* bit_map, | |
| 1507 OopTaskQueue* work_queue, | |
| 1508 CMSMarkStack* revisit_stack, | |
| 1509 Par_MarkRefsIntoAndScanClosure* cl): | |
| 1510 #ifdef ASSERT | |
| 1511 _collector(collector), | |
| 1512 _span(span), | |
| 1513 _work_queue(work_queue), | |
| 1514 #endif // ASSERT | |
| 1515 _parallel(true), | |
| 1516 _bit_map(bit_map), | |
| 1517 _par_scan_closure(cl) { } | |
| 1518 | |
| 1519 void do_object(oop obj) { | |
| 1520 guarantee(false, "Call do_object_b(oop, MemRegion) instead"); | |
| 1521 } | |
| 1522 bool do_object_b(oop obj) { | |
| 1523 guarantee(false, "Call do_object_b(oop, MemRegion) form instead"); | |
| 1524 return false; | |
| 1525 } | |
| 1526 bool do_object_bm(oop p, MemRegion mr); | |
| 1527 }; | |
| 1528 | |
| 1529 // This closure is used during the second checkpointing phase | |
| 1530 // to rescan the marked objects on the dirty cards in the mod | |
| 1531 // union table and the card table proper. It invokes | |
| 1532 // ScanMarkedObjectsAgainClosure above to accomplish much of its work. | |
| 1533 // In the parallel case, the bit map is shared and requires | |
| 1534 // synchronized access. | |
| 1535 class MarkFromDirtyCardsClosure: public MemRegionClosure { | |
| 1536 CompactibleFreeListSpace* _space; | |
| 1537 ScanMarkedObjectsAgainClosure _scan_cl; | |
| 1538 size_t _num_dirty_cards; | |
| 1539 | |
| 1540 public: | |
| 1541 MarkFromDirtyCardsClosure(CMSCollector* collector, | |
| 1542 MemRegion span, | |
| 1543 CompactibleFreeListSpace* space, | |
| 1544 CMSBitMap* bit_map, | |
| 1545 CMSMarkStack* mark_stack, | |
| 1546 CMSMarkStack* revisit_stack, | |
| 1547 MarkRefsIntoAndScanClosure* cl): | |
| 1548 _space(space), | |
| 1549 _num_dirty_cards(0), | |
| 1550 _scan_cl(collector, span, collector->ref_processor(), bit_map, | |
| 1551 mark_stack, revisit_stack, cl) { } | |
| 1552 | |
| 1553 MarkFromDirtyCardsClosure(CMSCollector* collector, | |
| 1554 MemRegion span, | |
| 1555 CompactibleFreeListSpace* space, | |
| 1556 CMSBitMap* bit_map, | |
| 1557 OopTaskQueue* work_queue, | |
| 1558 CMSMarkStack* revisit_stack, | |
| 1559 Par_MarkRefsIntoAndScanClosure* cl): | |
| 1560 _space(space), | |
| 1561 _num_dirty_cards(0), | |
| 1562 _scan_cl(collector, span, collector->ref_processor(), bit_map, | |
| 1563 work_queue, revisit_stack, cl) { } | |
| 1564 | |
| 1565 void do_MemRegion(MemRegion mr); | |
| 1566 void set_space(CompactibleFreeListSpace* space) { _space = space; } | |
| 1567 size_t num_dirty_cards() { return _num_dirty_cards; } | |
| 1568 }; | |
| 1569 | |
| 1570 // This closure is used in the non-product build to check | |
| 1571 // that there are no MemRegions with a certain property. | |
| 1572 class FalseMemRegionClosure: public MemRegionClosure { | |
| 1573 void do_MemRegion(MemRegion mr) { | |
| 1574 guarantee(!mr.is_empty(), "Shouldn't be empty"); | |
| 1575 guarantee(false, "Should never be here"); | |
| 1576 } | |
| 1577 }; | |
| 1578 | |
| 1579 // This closure is used during the precleaning phase | |
| 1580 // to "carefully" rescan marked objects on dirty cards. | |
| 1581 // It uses MarkRefsIntoAndScanClosure declared in genOopClosures.hpp | |
| 1582 // to accomplish some of its work. | |
| 1583 class ScanMarkedObjectsAgainCarefullyClosure: public ObjectClosureCareful { | |
| 1584 CMSCollector* _collector; | |
| 1585 MemRegion _span; | |
| 1586 bool _yield; | |
| 1587 Mutex* _freelistLock; | |
| 1588 CMSBitMap* _bitMap; | |
| 1589 CMSMarkStack* _markStack; | |
| 1590 MarkRefsIntoAndScanClosure* _scanningClosure; | |
| 1591 | |
| 1592 public: | |
| 1593 ScanMarkedObjectsAgainCarefullyClosure(CMSCollector* collector, | |
| 1594 MemRegion span, | |
| 1595 CMSBitMap* bitMap, | |
| 1596 CMSMarkStack* markStack, | |
| 1597 CMSMarkStack* revisitStack, | |
| 1598 MarkRefsIntoAndScanClosure* cl, | |
| 1599 bool should_yield): | |
| 1600 _collector(collector), | |
| 1601 _span(span), | |
| 1602 _yield(should_yield), | |
| 1603 _bitMap(bitMap), | |
| 1604 _markStack(markStack), | |
| 1605 _scanningClosure(cl) { | |
| 1606 } | |
| 1607 | |
| 1608 void do_object(oop p) { | |
| 1609 guarantee(false, "call do_object_careful instead"); | |
| 1610 } | |
| 1611 | |
| 1612 size_t do_object_careful(oop p) { | |
| 1613 guarantee(false, "Unexpected caller"); | |
| 1614 return 0; | |
| 1615 } | |
| 1616 | |
| 1617 size_t do_object_careful_m(oop p, MemRegion mr); | |
| 1618 | |
| 1619 void setFreelistLock(Mutex* m) { | |
| 1620 _freelistLock = m; | |
| 1621 _scanningClosure->set_freelistLock(m); | |
| 1622 } | |
| 1623 | |
| 1624 private: | |
| 1625 inline bool do_yield_check(); | |
| 1626 | |
| 1627 void do_yield_work(); | |
| 1628 }; | |
| 1629 | |
| 1630 class SurvivorSpacePrecleanClosure: public ObjectClosureCareful { | |
| 1631 CMSCollector* _collector; | |
| 1632 MemRegion _span; | |
| 1633 bool _yield; | |
| 1634 CMSBitMap* _bit_map; | |
| 1635 CMSMarkStack* _mark_stack; | |
| 1636 PushAndMarkClosure* _scanning_closure; | |
| 1637 unsigned int _before_count; | |
| 1638 | |
| 1639 public: | |
| 1640 SurvivorSpacePrecleanClosure(CMSCollector* collector, | |
| 1641 MemRegion span, | |
| 1642 CMSBitMap* bit_map, | |
| 1643 CMSMarkStack* mark_stack, | |
| 1644 PushAndMarkClosure* cl, | |
| 1645 unsigned int before_count, | |
| 1646 bool should_yield): | |
| 1647 _collector(collector), | |
| 1648 _span(span), | |
| 1649 _yield(should_yield), | |
| 1650 _bit_map(bit_map), | |
| 1651 _mark_stack(mark_stack), | |
| 1652 _scanning_closure(cl), | |
| 1653 _before_count(before_count) | |
| 1654 { } | |
| 1655 | |
| 1656 void do_object(oop p) { | |
| 1657 guarantee(false, "call do_object_careful instead"); | |
| 1658 } | |
| 1659 | |
| 1660 size_t do_object_careful(oop p); | |
| 1661 | |
| 1662 size_t do_object_careful_m(oop p, MemRegion mr) { | |
| 1663 guarantee(false, "Unexpected caller"); | |
| 1664 return 0; | |
| 1665 } | |
| 1666 | |
| 1667 private: | |
| 1668 inline void do_yield_check(); | |
| 1669 void do_yield_work(); | |
| 1670 }; | |
| 1671 | |
| 1672 // This closure is used to accomplish the sweeping work | |
| 1673 // after the second checkpoint but before the concurrent reset | |
| 1674 // phase. | |
| 1675 // | |
| 1676 // Terminology | |
| 1677 // left hand chunk (LHC) - block of one or more chunks currently being | |
| 1678 // coalesced. The LHC is available for coalescing with a new chunk. | |
| 1679 // right hand chunk (RHC) - block that is currently being swept that is | |
| 1680 // free or garbage that can be coalesced with the LHC. | |
| 1681 // _inFreeRange is true if there is currently a LHC | |
| 1682 // _lastFreeRangeCoalesced is true if the LHC consists of more than one chunk. | |
| 1683 // _freeRangeInFreeLists is true if the LHC is in the free lists. | |
| 1684 // _freeFinger is the address of the current LHC | |
| 1685 class SweepClosure: public BlkClosureCareful { | |
| 1686 CMSCollector* _collector; // collector doing the work | |
| 1687 ConcurrentMarkSweepGeneration* _g; // Generation being swept | |
| 1688 CompactibleFreeListSpace* _sp; // Space being swept | |
| 1689 HeapWord* _limit; | |
| 1690 Mutex* _freelistLock; // Free list lock (in space) | |
| 1691 CMSBitMap* _bitMap; // Marking bit map (in | |
| 1692 // generation) | |
| 1693 bool _inFreeRange; // Indicates if we are in the | |
| 1694 // midst of a free run | |
| 1695 bool _freeRangeInFreeLists; | |
| 1696 // Often, we have just found | |
| 1697 // a free chunk and started | |
| 1698 // a new free range; we do not | |
| 1699 // eagerly remove this chunk from | |
| 1700 // the free lists unless there is | |
| 1701 // a possibility of coalescing. | |
| 1702 // When true, this flag indicates | |
| 1703 // that the _freeFinger below | |
| 1704 // points to a potentially free chunk | |
| 1705 // that may still be in the free lists | |
| 1706 bool _lastFreeRangeCoalesced; | |
| 1707 // free range contains chunks | |
| 1708 // coalesced | |
| 1709 bool _yield; | |
| 1710 // Whether sweeping should be | |
| 1711 // done with yields. For instance | |
| 1712 // when done by the foreground | |
| 1713 // collector we shouldn't yield. | |
| 1714 HeapWord* _freeFinger; // When _inFreeRange is set, the | |
| 1715 // pointer to the "left hand | |
| 1716 // chunk" | |
| 1717 size_t _freeRangeSize; | |
| 1718 // When _inFreeRange is set, this | |
| 1719 // indicates the accumulated size | |
| 1720 // of the "left hand chunk" | |
| 1721 NOT_PRODUCT( | |
| 1722 size_t _numObjectsFreed; | |
| 1723 size_t _numWordsFreed; | |
| 1724 size_t _numObjectsLive; | |
| 1725 size_t _numWordsLive; | |
| 1726 size_t _numObjectsAlreadyFree; | |
| 1727 size_t _numWordsAlreadyFree; | |
| 1728 FreeChunk* _last_fc; | |
| 1729 ) | |
| 1730 private: | |
| 1731 // Code that is common to a free chunk or garbage when | |
| 1732 // encountered during sweeping. | |
| 1733 void doPostIsFreeOrGarbageChunk(FreeChunk *fc, | |
| 1734 size_t chunkSize); | |
| 1735 // Process a free chunk during sweeping. | |
| 1736 void doAlreadyFreeChunk(FreeChunk *fc); | |
| 1737 // Process a garbage chunk during sweeping. | |
| 1738 size_t doGarbageChunk(FreeChunk *fc); | |
| 1739 // Process a live chunk during sweeping. | |
| 1740 size_t doLiveChunk(FreeChunk* fc); | |
| 1741 | |
| 1742 // Accessors. | |
| 1743 HeapWord* freeFinger() const { return _freeFinger; } | |
| 1744 void set_freeFinger(HeapWord* v) { _freeFinger = v; } | |
| 1745 size_t freeRangeSize() const { return _freeRangeSize; } | |
| 1746 void set_freeRangeSize(size_t v) { _freeRangeSize = v; } | |
| 1747 bool inFreeRange() const { return _inFreeRange; } | |
| 1748 void set_inFreeRange(bool v) { _inFreeRange = v; } | |
| 1749 bool lastFreeRangeCoalesced() const { return _lastFreeRangeCoalesced; } | |
| 1750 void set_lastFreeRangeCoalesced(bool v) { _lastFreeRangeCoalesced = v; } | |
| 1751 bool freeRangeInFreeLists() const { return _freeRangeInFreeLists; } | |
| 1752 void set_freeRangeInFreeLists(bool v) { _freeRangeInFreeLists = v; } | |
| 1753 | |
| 1754 // Initialize a free range. | |
| 1755 void initialize_free_range(HeapWord* freeFinger, bool freeRangeInFreeLists); | |
| 1756 // Return this chunk to the free lists. | |
| 1757 void flushCurFreeChunk(HeapWord* chunk, size_t size); | |
| 1758 | |
| 1759 // Check if we should yield and do so when necessary. | |
| 1760 inline void do_yield_check(HeapWord* addr); | |
| 1761 | |
| 1762 // Yield | |
| 1763 void do_yield_work(HeapWord* addr); | |
| 1764 | |
| 1765 // Debugging/Printing | |
| 1766 void record_free_block_coalesced(FreeChunk* fc) const PRODUCT_RETURN; | |
| 1767 | |
| 1768 public: | |
| 1769 SweepClosure(CMSCollector* collector, ConcurrentMarkSweepGeneration* g, | |
| 1770 CMSBitMap* bitMap, bool should_yield); | |
| 1771 ~SweepClosure(); | |
| 1772 | |
| 1773 size_t do_blk_careful(HeapWord* addr); | |
| 1774 }; | |
| 1775 | |
| 1776 // Closures related to weak references processing | |
| 1777 | |
| 1778 // During CMS' weak reference processing, this is a | |
| 1779 // work-routine/closure used to complete transitive | |
| 1780 // marking of objects as live after a certain point | |
| 1781 // in which an initial set has been completely accumulated. | |
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1782 // This closure is currently used both during the final |
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1783 // remark stop-world phase, as well as during the concurrent |
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1784 // precleaning of the discovered reference lists. |
| 0 | 1785 class CMSDrainMarkingStackClosure: public VoidClosure { |
| 1786 CMSCollector* _collector; | |
| 1787 MemRegion _span; | |
| 1788 CMSMarkStack* _mark_stack; | |
| 1789 CMSBitMap* _bit_map; | |
| 1790 CMSKeepAliveClosure* _keep_alive; | |
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1791 bool _concurrent_precleaning; |
| 0 | 1792 public: |
| 1793 CMSDrainMarkingStackClosure(CMSCollector* collector, MemRegion span, | |
| 1794 CMSBitMap* bit_map, CMSMarkStack* mark_stack, | |
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1795 CMSKeepAliveClosure* keep_alive, |
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1796 bool cpc): |
| 0 | 1797 _collector(collector), |
| 1798 _span(span), | |
| 1799 _bit_map(bit_map), | |
| 1800 _mark_stack(mark_stack), | |
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1801 _keep_alive(keep_alive), |
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1802 _concurrent_precleaning(cpc) { |
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1803 assert(_concurrent_precleaning == _keep_alive->concurrent_precleaning(), |
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1804 "Mismatch"); |
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1805 } |
| 0 | 1806 |
| 1807 void do_void(); | |
| 1808 }; | |
| 1809 | |
| 1810 // A parallel version of CMSDrainMarkingStackClosure above. | |
| 1811 class CMSParDrainMarkingStackClosure: public VoidClosure { | |
| 1812 CMSCollector* _collector; | |
| 1813 MemRegion _span; | |
| 1814 OopTaskQueue* _work_queue; | |
| 1815 CMSBitMap* _bit_map; | |
| 1816 CMSInnerParMarkAndPushClosure _mark_and_push; | |
| 1817 | |
| 1818 public: | |
| 1819 CMSParDrainMarkingStackClosure(CMSCollector* collector, | |
| 1820 MemRegion span, CMSBitMap* bit_map, | |
| 935 | 1821 CMSMarkStack* revisit_stack, |
| 0 | 1822 OopTaskQueue* work_queue): |
| 1823 _collector(collector), | |
| 1824 _span(span), | |
| 1825 _bit_map(bit_map), | |
| 1826 _work_queue(work_queue), | |
| 935 | 1827 _mark_and_push(collector, span, bit_map, revisit_stack, work_queue) { } |
| 0 | 1828 |
| 1829 public: | |
| 1830 void trim_queue(uint max); | |
| 1831 void do_void(); | |
| 1832 }; | |
| 1833 | |
| 1834 // Allow yielding or short-circuiting of reference list | |
| 1835 // prelceaning work. | |
| 1836 class CMSPrecleanRefsYieldClosure: public YieldClosure { | |
| 1837 CMSCollector* _collector; | |
| 1838 void do_yield_work(); | |
| 1839 public: | |
| 1840 CMSPrecleanRefsYieldClosure(CMSCollector* collector): | |
| 1841 _collector(collector) {} | |
| 1842 virtual bool should_return(); | |
| 1843 }; | |
| 1844 | |
| 1845 | |
| 1846 // Convenience class that locks free list locks for given CMS collector | |
| 1847 class FreelistLocker: public StackObj { | |
| 1848 private: | |
| 1849 CMSCollector* _collector; | |
| 1850 public: | |
| 1851 FreelistLocker(CMSCollector* collector): | |
| 1852 _collector(collector) { | |
| 1853 _collector->getFreelistLocks(); | |
| 1854 } | |
| 1855 | |
| 1856 ~FreelistLocker() { | |
| 1857 _collector->releaseFreelistLocks(); | |
| 1858 } | |
| 1859 }; | |
| 1860 | |
| 1861 // Mark all dead objects in a given space. | |
| 1862 class MarkDeadObjectsClosure: public BlkClosure { | |
| 1863 const CMSCollector* _collector; | |
| 1864 const CompactibleFreeListSpace* _sp; | |
| 1865 CMSBitMap* _live_bit_map; | |
| 1866 CMSBitMap* _dead_bit_map; | |
| 1867 public: | |
| 1868 MarkDeadObjectsClosure(const CMSCollector* collector, | |
| 1869 const CompactibleFreeListSpace* sp, | |
| 1870 CMSBitMap *live_bit_map, | |
| 1871 CMSBitMap *dead_bit_map) : | |
| 1872 _collector(collector), | |
| 1873 _sp(sp), | |
| 1874 _live_bit_map(live_bit_map), | |
| 1875 _dead_bit_map(dead_bit_map) {} | |
| 1876 size_t do_blk(HeapWord* addr); | |
| 1877 }; | |
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1878 |
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1879 class TraceCMSMemoryManagerStats : public TraceMemoryManagerStats { |
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1880 |
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1881 public: |
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1882 TraceCMSMemoryManagerStats(CMSCollector::CollectorState phase); |
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1883 TraceCMSMemoryManagerStats(); |
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1884 }; |
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1885 |