Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/g1/concurrentMark.cpp @ 989:148e5441d916
6863023: need non-perm oops in code cache for JSR 292
Summary: Make a special root-list for those few nmethods which might contain non-perm oops.
Reviewed-by: twisti, kvn, never, jmasa, ysr
| author | jrose |
|---|---|
| date | Tue, 15 Sep 2009 21:53:47 -0700 |
| parents | 308762b2bf14 |
| children | 54b3b351d6f9 |
| rev | line source |
|---|---|
| 342 | 1 /* |
| 844 | 2 * Copyright 2001-2009 Sun Microsystems, Inc. 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 * | |
| 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
| 20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
| 21 * have any questions. | |
| 22 * | |
| 23 */ | |
| 24 | |
| 25 #include "incls/_precompiled.incl" | |
| 26 #include "incls/_concurrentMark.cpp.incl" | |
| 27 | |
| 28 // | |
| 29 // CMS Bit Map Wrapper | |
| 30 | |
| 31 CMBitMapRO::CMBitMapRO(ReservedSpace rs, int shifter): | |
| 32 _bm((uintptr_t*)NULL,0), | |
| 33 _shifter(shifter) { | |
| 34 _bmStartWord = (HeapWord*)(rs.base()); | |
| 35 _bmWordSize = rs.size()/HeapWordSize; // rs.size() is in bytes | |
| 36 ReservedSpace brs(ReservedSpace::allocation_align_size_up( | |
| 37 (_bmWordSize >> (_shifter + LogBitsPerByte)) + 1)); | |
| 38 | |
| 39 guarantee(brs.is_reserved(), "couldn't allocate CMS bit map"); | |
| 40 // For now we'll just commit all of the bit map up fromt. | |
| 41 // Later on we'll try to be more parsimonious with swap. | |
| 42 guarantee(_virtual_space.initialize(brs, brs.size()), | |
| 43 "couldn't reseve backing store for CMS bit map"); | |
| 44 assert(_virtual_space.committed_size() == brs.size(), | |
| 45 "didn't reserve backing store for all of CMS bit map?"); | |
| 46 _bm.set_map((uintptr_t*)_virtual_space.low()); | |
| 47 assert(_virtual_space.committed_size() << (_shifter + LogBitsPerByte) >= | |
| 48 _bmWordSize, "inconsistency in bit map sizing"); | |
| 49 _bm.set_size(_bmWordSize >> _shifter); | |
| 50 } | |
| 51 | |
| 52 HeapWord* CMBitMapRO::getNextMarkedWordAddress(HeapWord* addr, | |
| 53 HeapWord* limit) const { | |
| 54 // First we must round addr *up* to a possible object boundary. | |
| 55 addr = (HeapWord*)align_size_up((intptr_t)addr, | |
| 56 HeapWordSize << _shifter); | |
| 57 size_t addrOffset = heapWordToOffset(addr); | |
| 58 if (limit == NULL) limit = _bmStartWord + _bmWordSize; | |
| 59 size_t limitOffset = heapWordToOffset(limit); | |
| 60 size_t nextOffset = _bm.get_next_one_offset(addrOffset, limitOffset); | |
| 61 HeapWord* nextAddr = offsetToHeapWord(nextOffset); | |
| 62 assert(nextAddr >= addr, "get_next_one postcondition"); | |
| 63 assert(nextAddr == limit || isMarked(nextAddr), | |
| 64 "get_next_one postcondition"); | |
| 65 return nextAddr; | |
| 66 } | |
| 67 | |
| 68 HeapWord* CMBitMapRO::getNextUnmarkedWordAddress(HeapWord* addr, | |
| 69 HeapWord* limit) const { | |
| 70 size_t addrOffset = heapWordToOffset(addr); | |
| 71 if (limit == NULL) limit = _bmStartWord + _bmWordSize; | |
| 72 size_t limitOffset = heapWordToOffset(limit); | |
| 73 size_t nextOffset = _bm.get_next_zero_offset(addrOffset, limitOffset); | |
| 74 HeapWord* nextAddr = offsetToHeapWord(nextOffset); | |
| 75 assert(nextAddr >= addr, "get_next_one postcondition"); | |
| 76 assert(nextAddr == limit || !isMarked(nextAddr), | |
| 77 "get_next_one postcondition"); | |
| 78 return nextAddr; | |
| 79 } | |
| 80 | |
| 81 int CMBitMapRO::heapWordDiffToOffsetDiff(size_t diff) const { | |
| 82 assert((diff & ((1 << _shifter) - 1)) == 0, "argument check"); | |
| 83 return (int) (diff >> _shifter); | |
| 84 } | |
| 85 | |
| 86 bool CMBitMapRO::iterate(BitMapClosure* cl, MemRegion mr) { | |
| 87 HeapWord* left = MAX2(_bmStartWord, mr.start()); | |
| 88 HeapWord* right = MIN2(_bmStartWord + _bmWordSize, mr.end()); | |
| 89 if (right > left) { | |
| 90 // Right-open interval [leftOffset, rightOffset). | |
| 91 return _bm.iterate(cl, heapWordToOffset(left), heapWordToOffset(right)); | |
| 92 } else { | |
| 93 return true; | |
| 94 } | |
| 95 } | |
| 96 | |
| 97 void CMBitMapRO::mostly_disjoint_range_union(BitMap* from_bitmap, | |
| 98 size_t from_start_index, | |
| 99 HeapWord* to_start_word, | |
| 100 size_t word_num) { | |
| 101 _bm.mostly_disjoint_range_union(from_bitmap, | |
| 102 from_start_index, | |
| 103 heapWordToOffset(to_start_word), | |
| 104 word_num); | |
| 105 } | |
| 106 | |
| 107 #ifndef PRODUCT | |
| 108 bool CMBitMapRO::covers(ReservedSpace rs) const { | |
| 109 // assert(_bm.map() == _virtual_space.low(), "map inconsistency"); | |
|
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110 assert(((size_t)_bm.size() * (size_t)(1 << _shifter)) == _bmWordSize, |
| 342 | 111 "size inconsistency"); |
| 112 return _bmStartWord == (HeapWord*)(rs.base()) && | |
| 113 _bmWordSize == rs.size()>>LogHeapWordSize; | |
| 114 } | |
| 115 #endif | |
| 116 | |
| 117 void CMBitMap::clearAll() { | |
| 118 _bm.clear(); | |
| 119 return; | |
| 120 } | |
| 121 | |
| 122 void CMBitMap::markRange(MemRegion mr) { | |
| 123 mr.intersection(MemRegion(_bmStartWord, _bmWordSize)); | |
| 124 assert(!mr.is_empty(), "unexpected empty region"); | |
| 125 assert((offsetToHeapWord(heapWordToOffset(mr.end())) == | |
| 126 ((HeapWord *) mr.end())), | |
| 127 "markRange memory region end is not card aligned"); | |
| 128 // convert address range into offset range | |
| 129 _bm.at_put_range(heapWordToOffset(mr.start()), | |
| 130 heapWordToOffset(mr.end()), true); | |
| 131 } | |
| 132 | |
| 133 void CMBitMap::clearRange(MemRegion mr) { | |
| 134 mr.intersection(MemRegion(_bmStartWord, _bmWordSize)); | |
| 135 assert(!mr.is_empty(), "unexpected empty region"); | |
| 136 // convert address range into offset range | |
| 137 _bm.at_put_range(heapWordToOffset(mr.start()), | |
| 138 heapWordToOffset(mr.end()), false); | |
| 139 } | |
| 140 | |
| 141 MemRegion CMBitMap::getAndClearMarkedRegion(HeapWord* addr, | |
| 142 HeapWord* end_addr) { | |
| 143 HeapWord* start = getNextMarkedWordAddress(addr); | |
| 144 start = MIN2(start, end_addr); | |
| 145 HeapWord* end = getNextUnmarkedWordAddress(start); | |
| 146 end = MIN2(end, end_addr); | |
| 147 assert(start <= end, "Consistency check"); | |
| 148 MemRegion mr(start, end); | |
| 149 if (!mr.is_empty()) { | |
| 150 clearRange(mr); | |
| 151 } | |
| 152 return mr; | |
| 153 } | |
| 154 | |
| 155 CMMarkStack::CMMarkStack(ConcurrentMark* cm) : | |
| 156 _base(NULL), _cm(cm) | |
| 157 #ifdef ASSERT | |
| 158 , _drain_in_progress(false) | |
| 159 , _drain_in_progress_yields(false) | |
| 160 #endif | |
| 161 {} | |
| 162 | |
| 163 void CMMarkStack::allocate(size_t size) { | |
| 164 _base = NEW_C_HEAP_ARRAY(oop, size); | |
| 165 if (_base == NULL) | |
| 166 vm_exit_during_initialization("Failed to allocate " | |
| 167 "CM region mark stack"); | |
| 168 _index = 0; | |
| 169 // QQQQ cast ... | |
| 170 _capacity = (jint) size; | |
| 171 _oops_do_bound = -1; | |
| 172 NOT_PRODUCT(_max_depth = 0); | |
| 173 } | |
| 174 | |
| 175 CMMarkStack::~CMMarkStack() { | |
| 176 if (_base != NULL) FREE_C_HEAP_ARRAY(oop, _base); | |
| 177 } | |
| 178 | |
| 179 void CMMarkStack::par_push(oop ptr) { | |
| 180 while (true) { | |
| 181 if (isFull()) { | |
| 182 _overflow = true; | |
| 183 return; | |
| 184 } | |
| 185 // Otherwise... | |
| 186 jint index = _index; | |
| 187 jint next_index = index+1; | |
| 188 jint res = Atomic::cmpxchg(next_index, &_index, index); | |
| 189 if (res == index) { | |
| 190 _base[index] = ptr; | |
| 191 // Note that we don't maintain this atomically. We could, but it | |
| 192 // doesn't seem necessary. | |
| 193 NOT_PRODUCT(_max_depth = MAX2(_max_depth, next_index)); | |
| 194 return; | |
| 195 } | |
| 196 // Otherwise, we need to try again. | |
| 197 } | |
| 198 } | |
| 199 | |
| 200 void CMMarkStack::par_adjoin_arr(oop* ptr_arr, int n) { | |
| 201 while (true) { | |
| 202 if (isFull()) { | |
| 203 _overflow = true; | |
| 204 return; | |
| 205 } | |
| 206 // Otherwise... | |
| 207 jint index = _index; | |
| 208 jint next_index = index + n; | |
| 209 if (next_index > _capacity) { | |
| 210 _overflow = true; | |
| 211 return; | |
| 212 } | |
| 213 jint res = Atomic::cmpxchg(next_index, &_index, index); | |
| 214 if (res == index) { | |
| 215 for (int i = 0; i < n; i++) { | |
| 216 int ind = index + i; | |
| 217 assert(ind < _capacity, "By overflow test above."); | |
| 218 _base[ind] = ptr_arr[i]; | |
| 219 } | |
| 220 NOT_PRODUCT(_max_depth = MAX2(_max_depth, next_index)); | |
| 221 return; | |
| 222 } | |
| 223 // Otherwise, we need to try again. | |
| 224 } | |
| 225 } | |
| 226 | |
| 227 | |
| 228 void CMMarkStack::par_push_arr(oop* ptr_arr, int n) { | |
| 229 MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag); | |
| 230 jint start = _index; | |
| 231 jint next_index = start + n; | |
| 232 if (next_index > _capacity) { | |
| 233 _overflow = true; | |
| 234 return; | |
| 235 } | |
| 236 // Otherwise. | |
| 237 _index = next_index; | |
| 238 for (int i = 0; i < n; i++) { | |
| 239 int ind = start + i; | |
| 240 guarantee(ind < _capacity, "By overflow test above."); | |
| 241 _base[ind] = ptr_arr[i]; | |
| 242 } | |
| 243 } | |
| 244 | |
| 245 | |
| 246 bool CMMarkStack::par_pop_arr(oop* ptr_arr, int max, int* n) { | |
| 247 MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag); | |
| 248 jint index = _index; | |
| 249 if (index == 0) { | |
| 250 *n = 0; | |
| 251 return false; | |
| 252 } else { | |
| 253 int k = MIN2(max, index); | |
| 254 jint new_ind = index - k; | |
| 255 for (int j = 0; j < k; j++) { | |
| 256 ptr_arr[j] = _base[new_ind + j]; | |
| 257 } | |
| 258 _index = new_ind; | |
| 259 *n = k; | |
| 260 return true; | |
| 261 } | |
| 262 } | |
| 263 | |
| 264 | |
| 265 CMRegionStack::CMRegionStack() : _base(NULL) {} | |
| 266 | |
| 267 void CMRegionStack::allocate(size_t size) { | |
| 268 _base = NEW_C_HEAP_ARRAY(MemRegion, size); | |
| 269 if (_base == NULL) | |
| 270 vm_exit_during_initialization("Failed to allocate " | |
| 271 "CM region mark stack"); | |
| 272 _index = 0; | |
| 273 // QQQQ cast ... | |
| 274 _capacity = (jint) size; | |
| 275 } | |
| 276 | |
| 277 CMRegionStack::~CMRegionStack() { | |
| 278 if (_base != NULL) FREE_C_HEAP_ARRAY(oop, _base); | |
| 279 } | |
| 280 | |
| 281 void CMRegionStack::push(MemRegion mr) { | |
| 282 assert(mr.word_size() > 0, "Precondition"); | |
| 283 while (true) { | |
| 284 if (isFull()) { | |
| 285 _overflow = true; | |
| 286 return; | |
| 287 } | |
| 288 // Otherwise... | |
| 289 jint index = _index; | |
| 290 jint next_index = index+1; | |
| 291 jint res = Atomic::cmpxchg(next_index, &_index, index); | |
| 292 if (res == index) { | |
| 293 _base[index] = mr; | |
| 294 return; | |
| 295 } | |
| 296 // Otherwise, we need to try again. | |
| 297 } | |
| 298 } | |
| 299 | |
| 300 MemRegion CMRegionStack::pop() { | |
| 301 while (true) { | |
| 302 // Otherwise... | |
| 303 jint index = _index; | |
| 304 | |
| 305 if (index == 0) { | |
| 306 return MemRegion(); | |
| 307 } | |
| 308 jint next_index = index-1; | |
| 309 jint res = Atomic::cmpxchg(next_index, &_index, index); | |
| 310 if (res == index) { | |
| 311 MemRegion mr = _base[next_index]; | |
| 312 if (mr.start() != NULL) { | |
| 313 tmp_guarantee_CM( mr.end() != NULL, "invariant" ); | |
| 314 tmp_guarantee_CM( mr.word_size() > 0, "invariant" ); | |
| 315 return mr; | |
| 316 } else { | |
| 317 // that entry was invalidated... let's skip it | |
| 318 tmp_guarantee_CM( mr.end() == NULL, "invariant" ); | |
| 319 } | |
| 320 } | |
| 321 // Otherwise, we need to try again. | |
| 322 } | |
| 323 } | |
| 324 | |
| 325 bool CMRegionStack::invalidate_entries_into_cset() { | |
| 326 bool result = false; | |
| 327 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 328 for (int i = 0; i < _oops_do_bound; ++i) { | |
| 329 MemRegion mr = _base[i]; | |
| 330 if (mr.start() != NULL) { | |
| 331 tmp_guarantee_CM( mr.end() != NULL, "invariant"); | |
| 332 tmp_guarantee_CM( mr.word_size() > 0, "invariant" ); | |
| 333 HeapRegion* hr = g1h->heap_region_containing(mr.start()); | |
| 334 tmp_guarantee_CM( hr != NULL, "invariant" ); | |
| 335 if (hr->in_collection_set()) { | |
| 336 // The region points into the collection set | |
| 337 _base[i] = MemRegion(); | |
| 338 result = true; | |
| 339 } | |
| 340 } else { | |
| 341 // that entry was invalidated... let's skip it | |
| 342 tmp_guarantee_CM( mr.end() == NULL, "invariant" ); | |
| 343 } | |
| 344 } | |
| 345 return result; | |
| 346 } | |
| 347 | |
| 348 template<class OopClosureClass> | |
| 349 bool CMMarkStack::drain(OopClosureClass* cl, CMBitMap* bm, bool yield_after) { | |
| 350 assert(!_drain_in_progress || !_drain_in_progress_yields || yield_after | |
| 351 || SafepointSynchronize::is_at_safepoint(), | |
| 352 "Drain recursion must be yield-safe."); | |
| 353 bool res = true; | |
| 354 debug_only(_drain_in_progress = true); | |
| 355 debug_only(_drain_in_progress_yields = yield_after); | |
| 356 while (!isEmpty()) { | |
| 357 oop newOop = pop(); | |
| 358 assert(G1CollectedHeap::heap()->is_in_reserved(newOop), "Bad pop"); | |
| 359 assert(newOop->is_oop(), "Expected an oop"); | |
| 360 assert(bm == NULL || bm->isMarked((HeapWord*)newOop), | |
| 361 "only grey objects on this stack"); | |
| 362 // iterate over the oops in this oop, marking and pushing | |
| 363 // the ones in CMS generation. | |
| 364 newOop->oop_iterate(cl); | |
| 365 if (yield_after && _cm->do_yield_check()) { | |
| 366 res = false; break; | |
| 367 } | |
| 368 } | |
| 369 debug_only(_drain_in_progress = false); | |
| 370 return res; | |
| 371 } | |
| 372 | |
| 373 void CMMarkStack::oops_do(OopClosure* f) { | |
| 374 if (_index == 0) return; | |
| 375 assert(_oops_do_bound != -1 && _oops_do_bound <= _index, | |
| 376 "Bound must be set."); | |
| 377 for (int i = 0; i < _oops_do_bound; i++) { | |
| 378 f->do_oop(&_base[i]); | |
| 379 } | |
| 380 _oops_do_bound = -1; | |
| 381 } | |
| 382 | |
| 383 bool ConcurrentMark::not_yet_marked(oop obj) const { | |
| 384 return (_g1h->is_obj_ill(obj) | |
| 385 || (_g1h->is_in_permanent(obj) | |
| 386 && !nextMarkBitMap()->isMarked((HeapWord*)obj))); | |
| 387 } | |
| 388 | |
| 389 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away | |
| 390 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list | |
| 391 #endif // _MSC_VER | |
| 392 | |
| 393 ConcurrentMark::ConcurrentMark(ReservedSpace rs, | |
| 394 int max_regions) : | |
| 395 _markBitMap1(rs, MinObjAlignment - 1), | |
| 396 _markBitMap2(rs, MinObjAlignment - 1), | |
| 397 | |
| 398 _parallel_marking_threads(0), | |
| 399 _sleep_factor(0.0), | |
| 400 _marking_task_overhead(1.0), | |
| 401 _cleanup_sleep_factor(0.0), | |
| 402 _cleanup_task_overhead(1.0), | |
| 403 _region_bm(max_regions, false /* in_resource_area*/), | |
| 404 _card_bm((rs.size() + CardTableModRefBS::card_size - 1) >> | |
| 405 CardTableModRefBS::card_shift, | |
| 406 false /* in_resource_area*/), | |
| 407 _prevMarkBitMap(&_markBitMap1), | |
| 408 _nextMarkBitMap(&_markBitMap2), | |
| 409 _at_least_one_mark_complete(false), | |
| 410 | |
| 411 _markStack(this), | |
| 412 _regionStack(), | |
| 413 // _finger set in set_non_marking_state | |
| 414 | |
| 415 _max_task_num(MAX2(ParallelGCThreads, (size_t)1)), | |
| 416 // _active_tasks set in set_non_marking_state | |
| 417 // _tasks set inside the constructor | |
| 418 _task_queues(new CMTaskQueueSet((int) _max_task_num)), | |
| 419 _terminator(ParallelTaskTerminator((int) _max_task_num, _task_queues)), | |
| 420 | |
| 421 _has_overflown(false), | |
| 422 _concurrent(false), | |
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423 _has_aborted(false), |
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424 _restart_for_overflow(false), |
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425 _concurrent_marking_in_progress(false), |
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426 _should_gray_objects(false), |
| 342 | 427 |
| 428 // _verbose_level set below | |
| 429 | |
| 430 _init_times(), | |
| 431 _remark_times(), _remark_mark_times(), _remark_weak_ref_times(), | |
| 432 _cleanup_times(), | |
| 433 _total_counting_time(0.0), | |
| 434 _total_rs_scrub_time(0.0), | |
| 435 | |
| 436 _parallel_workers(NULL), | |
| 437 _cleanup_co_tracker(G1CLGroup) | |
| 438 { | |
| 439 CMVerboseLevel verbose_level = | |
| 440 (CMVerboseLevel) G1MarkingVerboseLevel; | |
| 441 if (verbose_level < no_verbose) | |
| 442 verbose_level = no_verbose; | |
| 443 if (verbose_level > high_verbose) | |
| 444 verbose_level = high_verbose; | |
| 445 _verbose_level = verbose_level; | |
| 446 | |
| 447 if (verbose_low()) | |
| 448 gclog_or_tty->print_cr("[global] init, heap start = "PTR_FORMAT", " | |
| 449 "heap end = "PTR_FORMAT, _heap_start, _heap_end); | |
| 450 | |
| 751 | 451 _markStack.allocate(G1MarkStackSize); |
| 452 _regionStack.allocate(G1MarkRegionStackSize); | |
| 342 | 453 |
| 454 // Create & start a ConcurrentMark thread. | |
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455 _cmThread = new ConcurrentMarkThread(this); |
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456 assert(cmThread() != NULL, "CM Thread should have been created"); |
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457 assert(cmThread()->cm() != NULL, "CM Thread should refer to this cm"); |
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458 |
| 342 | 459 _g1h = G1CollectedHeap::heap(); |
| 460 assert(CGC_lock != NULL, "Where's the CGC_lock?"); | |
| 461 assert(_markBitMap1.covers(rs), "_markBitMap1 inconsistency"); | |
| 462 assert(_markBitMap2.covers(rs), "_markBitMap2 inconsistency"); | |
| 463 | |
| 464 SATBMarkQueueSet& satb_qs = JavaThread::satb_mark_queue_set(); | |
| 465 satb_qs.set_buffer_size(G1SATBLogBufferSize); | |
| 466 | |
| 467 int size = (int) MAX2(ParallelGCThreads, (size_t)1); | |
| 468 _par_cleanup_thread_state = NEW_C_HEAP_ARRAY(ParCleanupThreadState*, size); | |
| 469 for (int i = 0 ; i < size; i++) { | |
| 470 _par_cleanup_thread_state[i] = new ParCleanupThreadState; | |
| 471 } | |
| 472 | |
| 473 _tasks = NEW_C_HEAP_ARRAY(CMTask*, _max_task_num); | |
| 474 _accum_task_vtime = NEW_C_HEAP_ARRAY(double, _max_task_num); | |
| 475 | |
| 476 // so that the assertion in MarkingTaskQueue::task_queue doesn't fail | |
| 477 _active_tasks = _max_task_num; | |
| 478 for (int i = 0; i < (int) _max_task_num; ++i) { | |
| 479 CMTaskQueue* task_queue = new CMTaskQueue(); | |
| 480 task_queue->initialize(); | |
| 481 _task_queues->register_queue(i, task_queue); | |
| 482 | |
| 483 _tasks[i] = new CMTask(i, this, task_queue, _task_queues); | |
| 484 _accum_task_vtime[i] = 0.0; | |
| 485 } | |
| 486 | |
| 487 if (ParallelMarkingThreads > ParallelGCThreads) { | |
| 488 vm_exit_during_initialization("Can't have more ParallelMarkingThreads " | |
| 489 "than ParallelGCThreads."); | |
| 490 } | |
| 491 if (ParallelGCThreads == 0) { | |
| 492 // if we are not running with any parallel GC threads we will not | |
| 493 // spawn any marking threads either | |
| 494 _parallel_marking_threads = 0; | |
| 495 _sleep_factor = 0.0; | |
| 496 _marking_task_overhead = 1.0; | |
| 497 } else { | |
| 498 if (ParallelMarkingThreads > 0) { | |
| 751 | 499 // notice that ParallelMarkingThreads overwrites G1MarkingOverheadPercent |
| 342 | 500 // if both are set |
| 501 | |
| 502 _parallel_marking_threads = ParallelMarkingThreads; | |
| 503 _sleep_factor = 0.0; | |
| 504 _marking_task_overhead = 1.0; | |
| 751 | 505 } else if (G1MarkingOverheadPercent > 0) { |
| 342 | 506 // we will calculate the number of parallel marking threads |
| 507 // based on a target overhead with respect to the soft real-time | |
| 508 // goal | |
| 509 | |
| 751 | 510 double marking_overhead = (double) G1MarkingOverheadPercent / 100.0; |
| 342 | 511 double overall_cm_overhead = |
| 751 | 512 (double) MaxGCPauseMillis * marking_overhead / |
| 513 (double) GCPauseIntervalMillis; | |
| 342 | 514 double cpu_ratio = 1.0 / (double) os::processor_count(); |
| 515 double marking_thread_num = ceil(overall_cm_overhead / cpu_ratio); | |
| 516 double marking_task_overhead = | |
| 517 overall_cm_overhead / marking_thread_num * | |
| 518 (double) os::processor_count(); | |
| 519 double sleep_factor = | |
| 520 (1.0 - marking_task_overhead) / marking_task_overhead; | |
| 521 | |
| 522 _parallel_marking_threads = (size_t) marking_thread_num; | |
| 523 _sleep_factor = sleep_factor; | |
| 524 _marking_task_overhead = marking_task_overhead; | |
| 525 } else { | |
| 526 _parallel_marking_threads = MAX2((ParallelGCThreads + 2) / 4, (size_t)1); | |
| 527 _sleep_factor = 0.0; | |
| 528 _marking_task_overhead = 1.0; | |
| 529 } | |
| 530 | |
| 531 if (parallel_marking_threads() > 1) | |
| 532 _cleanup_task_overhead = 1.0; | |
| 533 else | |
| 534 _cleanup_task_overhead = marking_task_overhead(); | |
| 535 _cleanup_sleep_factor = | |
| 536 (1.0 - cleanup_task_overhead()) / cleanup_task_overhead(); | |
| 537 | |
| 538 #if 0 | |
| 539 gclog_or_tty->print_cr("Marking Threads %d", parallel_marking_threads()); | |
| 540 gclog_or_tty->print_cr("CM Marking Task Overhead %1.4lf", marking_task_overhead()); | |
| 541 gclog_or_tty->print_cr("CM Sleep Factor %1.4lf", sleep_factor()); | |
| 542 gclog_or_tty->print_cr("CL Marking Task Overhead %1.4lf", cleanup_task_overhead()); | |
| 543 gclog_or_tty->print_cr("CL Sleep Factor %1.4lf", cleanup_sleep_factor()); | |
| 544 #endif | |
| 545 | |
| 546 guarantee( parallel_marking_threads() > 0, "peace of mind" ); | |
| 547 _parallel_workers = new WorkGang("Parallel Marking Threads", | |
| 548 (int) parallel_marking_threads(), false, true); | |
| 549 if (_parallel_workers == NULL) | |
| 550 vm_exit_during_initialization("Failed necessary allocation."); | |
| 551 } | |
| 552 | |
| 553 // so that the call below can read a sensible value | |
| 554 _heap_start = (HeapWord*) rs.base(); | |
| 555 set_non_marking_state(); | |
| 556 } | |
| 557 | |
| 558 void ConcurrentMark::update_g1_committed(bool force) { | |
| 559 // If concurrent marking is not in progress, then we do not need to | |
| 560 // update _heap_end. This has a subtle and important | |
| 561 // side-effect. Imagine that two evacuation pauses happen between | |
| 562 // marking completion and remark. The first one can grow the | |
| 563 // heap (hence now the finger is below the heap end). Then, the | |
| 564 // second one could unnecessarily push regions on the region | |
| 565 // stack. This causes the invariant that the region stack is empty | |
| 566 // at the beginning of remark to be false. By ensuring that we do | |
| 567 // not observe heap expansions after marking is complete, then we do | |
| 568 // not have this problem. | |
| 569 if (!concurrent_marking_in_progress() && !force) | |
| 570 return; | |
| 571 | |
| 572 MemRegion committed = _g1h->g1_committed(); | |
| 573 tmp_guarantee_CM( committed.start() == _heap_start, | |
| 574 "start shouldn't change" ); | |
| 575 HeapWord* new_end = committed.end(); | |
| 576 if (new_end > _heap_end) { | |
| 577 // The heap has been expanded. | |
| 578 | |
| 579 _heap_end = new_end; | |
| 580 } | |
| 581 // Notice that the heap can also shrink. However, this only happens | |
| 582 // during a Full GC (at least currently) and the entire marking | |
| 583 // phase will bail out and the task will not be restarted. So, let's | |
| 584 // do nothing. | |
| 585 } | |
| 586 | |
| 587 void ConcurrentMark::reset() { | |
| 588 // Starting values for these two. This should be called in a STW | |
| 589 // phase. CM will be notified of any future g1_committed expansions | |
| 590 // will be at the end of evacuation pauses, when tasks are | |
| 591 // inactive. | |
| 592 MemRegion committed = _g1h->g1_committed(); | |
| 593 _heap_start = committed.start(); | |
| 594 _heap_end = committed.end(); | |
| 595 | |
| 596 guarantee( _heap_start != NULL && | |
| 597 _heap_end != NULL && | |
| 598 _heap_start < _heap_end, "heap bounds should look ok" ); | |
| 599 | |
| 600 // reset all the marking data structures and any necessary flags | |
| 601 clear_marking_state(); | |
| 602 | |
| 603 if (verbose_low()) | |
| 604 gclog_or_tty->print_cr("[global] resetting"); | |
| 605 | |
| 606 // We do reset all of them, since different phases will use | |
| 607 // different number of active threads. So, it's easiest to have all | |
| 608 // of them ready. | |
| 609 for (int i = 0; i < (int) _max_task_num; ++i) | |
| 610 _tasks[i]->reset(_nextMarkBitMap); | |
| 611 | |
| 612 // we need this to make sure that the flag is on during the evac | |
| 613 // pause with initial mark piggy-backed | |
| 614 set_concurrent_marking_in_progress(); | |
| 615 } | |
| 616 | |
| 617 void ConcurrentMark::set_phase(size_t active_tasks, bool concurrent) { | |
| 618 guarantee( active_tasks <= _max_task_num, "we should not have more" ); | |
| 619 | |
| 620 _active_tasks = active_tasks; | |
| 621 // Need to update the three data structures below according to the | |
| 622 // number of active threads for this phase. | |
| 623 _terminator = ParallelTaskTerminator((int) active_tasks, _task_queues); | |
| 624 _first_overflow_barrier_sync.set_n_workers((int) active_tasks); | |
| 625 _second_overflow_barrier_sync.set_n_workers((int) active_tasks); | |
| 626 | |
| 627 _concurrent = concurrent; | |
| 628 // We propagate this to all tasks, not just the active ones. | |
| 629 for (int i = 0; i < (int) _max_task_num; ++i) | |
| 630 _tasks[i]->set_concurrent(concurrent); | |
| 631 | |
| 632 if (concurrent) { | |
| 633 set_concurrent_marking_in_progress(); | |
| 634 } else { | |
| 635 // We currently assume that the concurrent flag has been set to | |
| 636 // false before we start remark. At this point we should also be | |
| 637 // in a STW phase. | |
| 638 guarantee( !concurrent_marking_in_progress(), "invariant" ); | |
| 639 guarantee( _finger == _heap_end, "only way to get here" ); | |
| 640 update_g1_committed(true); | |
| 641 } | |
| 642 } | |
| 643 | |
| 644 void ConcurrentMark::set_non_marking_state() { | |
| 645 // We set the global marking state to some default values when we're | |
| 646 // not doing marking. | |
| 647 clear_marking_state(); | |
| 648 _active_tasks = 0; | |
| 649 clear_concurrent_marking_in_progress(); | |
| 650 } | |
| 651 | |
| 652 ConcurrentMark::~ConcurrentMark() { | |
| 653 int size = (int) MAX2(ParallelGCThreads, (size_t)1); | |
| 654 for (int i = 0; i < size; i++) delete _par_cleanup_thread_state[i]; | |
| 655 FREE_C_HEAP_ARRAY(ParCleanupThreadState*, | |
| 656 _par_cleanup_thread_state); | |
| 657 | |
| 658 for (int i = 0; i < (int) _max_task_num; ++i) { | |
| 659 delete _task_queues->queue(i); | |
| 660 delete _tasks[i]; | |
| 661 } | |
| 662 delete _task_queues; | |
| 663 FREE_C_HEAP_ARRAY(CMTask*, _max_task_num); | |
| 664 } | |
| 665 | |
| 666 // This closure is used to mark refs into the g1 generation | |
| 667 // from external roots in the CMS bit map. | |
| 668 // Called at the first checkpoint. | |
| 669 // | |
| 670 | |
| 671 #define PRINT_REACHABLE_AT_INITIAL_MARK 0 | |
| 672 #if PRINT_REACHABLE_AT_INITIAL_MARK | |
| 673 static FILE* reachable_file = NULL; | |
| 674 | |
| 675 class PrintReachableClosure: public OopsInGenClosure { | |
| 676 CMBitMap* _bm; | |
| 677 int _level; | |
| 678 public: | |
| 679 PrintReachableClosure(CMBitMap* bm) : | |
| 680 _bm(bm), _level(0) { | |
| 681 guarantee(reachable_file != NULL, "pre-condition"); | |
| 682 } | |
| 683 void do_oop(oop* p) { | |
| 684 oop obj = *p; | |
| 685 HeapWord* obj_addr = (HeapWord*)obj; | |
| 686 if (obj == NULL) return; | |
| 687 fprintf(reachable_file, "%d: "PTR_FORMAT" -> "PTR_FORMAT" (%d)\n", | |
| 688 _level, p, (void*) obj, _bm->isMarked(obj_addr)); | |
| 689 if (!_bm->isMarked(obj_addr)) { | |
| 690 _bm->mark(obj_addr); | |
| 691 _level++; | |
| 692 obj->oop_iterate(this); | |
| 693 _level--; | |
| 694 } | |
| 695 } | |
| 696 }; | |
| 697 #endif // PRINT_REACHABLE_AT_INITIAL_MARK | |
| 698 | |
| 699 #define SEND_HEAP_DUMP_TO_FILE 0 | |
| 700 #if SEND_HEAP_DUMP_TO_FILE | |
| 701 static FILE* heap_dump_file = NULL; | |
| 702 #endif // SEND_HEAP_DUMP_TO_FILE | |
| 703 | |
| 704 void ConcurrentMark::clearNextBitmap() { | |
| 705 guarantee(!G1CollectedHeap::heap()->mark_in_progress(), "Precondition."); | |
| 706 | |
| 707 // clear the mark bitmap (no grey objects to start with). | |
| 708 // We need to do this in chunks and offer to yield in between | |
| 709 // each chunk. | |
| 710 HeapWord* start = _nextMarkBitMap->startWord(); | |
| 711 HeapWord* end = _nextMarkBitMap->endWord(); | |
| 712 HeapWord* cur = start; | |
| 713 size_t chunkSize = M; | |
| 714 while (cur < end) { | |
| 715 HeapWord* next = cur + chunkSize; | |
| 716 if (next > end) | |
| 717 next = end; | |
| 718 MemRegion mr(cur,next); | |
| 719 _nextMarkBitMap->clearRange(mr); | |
| 720 cur = next; | |
| 721 do_yield_check(); | |
| 722 } | |
| 723 } | |
| 724 | |
| 725 class NoteStartOfMarkHRClosure: public HeapRegionClosure { | |
| 726 public: | |
| 727 bool doHeapRegion(HeapRegion* r) { | |
| 728 if (!r->continuesHumongous()) { | |
| 729 r->note_start_of_marking(true); | |
| 730 } | |
| 731 return false; | |
| 732 } | |
| 733 }; | |
| 734 | |
| 735 void ConcurrentMark::checkpointRootsInitialPre() { | |
| 736 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 737 G1CollectorPolicy* g1p = g1h->g1_policy(); | |
| 738 | |
| 739 _has_aborted = false; | |
| 740 | |
| 741 // Find all the reachable objects... | |
| 742 #if PRINT_REACHABLE_AT_INITIAL_MARK | |
| 743 guarantee(reachable_file == NULL, "Protocol"); | |
| 744 char fn_buf[100]; | |
| 745 sprintf(fn_buf, "/tmp/reachable.txt.%d", os::current_process_id()); | |
| 746 reachable_file = fopen(fn_buf, "w"); | |
| 747 // clear the mark bitmap (no grey objects to start with) | |
| 748 _nextMarkBitMap->clearAll(); | |
| 749 PrintReachableClosure prcl(_nextMarkBitMap); | |
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750 g1h->process_strong_roots(true, // activate StrongRootsScope |
| 342 | 751 false, // fake perm gen collection |
| 752 SharedHeap::SO_AllClasses, | |
| 753 &prcl, // Regular roots | |
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754 NULL, // do not visit active blobs |
| 342 | 755 &prcl // Perm Gen Roots |
| 756 ); | |
| 757 // The root iteration above "consumed" dirty cards in the perm gen. | |
| 758 // Therefore, as a shortcut, we dirty all such cards. | |
| 759 g1h->rem_set()->invalidate(g1h->perm_gen()->used_region(), false); | |
| 760 fclose(reachable_file); | |
| 761 reachable_file = NULL; | |
| 762 // clear the mark bitmap again. | |
| 763 _nextMarkBitMap->clearAll(); | |
| 764 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); | |
| 765 COMPILER2_PRESENT(DerivedPointerTable::clear()); | |
| 766 #endif // PRINT_REACHABLE_AT_INITIAL_MARK | |
| 767 | |
| 768 // Initialise marking structures. This has to be done in a STW phase. | |
| 769 reset(); | |
| 770 } | |
| 771 | |
| 772 class CMMarkRootsClosure: public OopsInGenClosure { | |
| 773 private: | |
| 774 ConcurrentMark* _cm; | |
| 775 G1CollectedHeap* _g1h; | |
| 776 bool _do_barrier; | |
| 777 | |
| 778 public: | |
| 779 CMMarkRootsClosure(ConcurrentMark* cm, | |
| 780 G1CollectedHeap* g1h, | |
| 781 bool do_barrier) : _cm(cm), _g1h(g1h), | |
| 782 _do_barrier(do_barrier) { } | |
| 783 | |
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784 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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785 virtual void do_oop( oop* p) { do_oop_work(p); } |
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786 |
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787 template <class T> void do_oop_work(T* p) { |
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788 T heap_oop = oopDesc::load_heap_oop(p); |
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789 if (!oopDesc::is_null(heap_oop)) { |
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790 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); |
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791 assert(obj->is_oop() || obj->mark() == NULL, |
| 342 | 792 "expected an oop, possibly with mark word displaced"); |
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793 HeapWord* addr = (HeapWord*)obj; |
| 342 | 794 if (_g1h->is_in_g1_reserved(addr)) { |
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795 _cm->grayRoot(obj); |
| 342 | 796 } |
| 797 } | |
| 798 if (_do_barrier) { | |
| 799 assert(!_g1h->is_in_g1_reserved(p), | |
| 800 "Should be called on external roots"); | |
| 801 do_barrier(p); | |
| 802 } | |
| 803 } | |
| 804 }; | |
| 805 | |
| 806 void ConcurrentMark::checkpointRootsInitialPost() { | |
| 807 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 808 | |
| 809 // For each region note start of marking. | |
| 810 NoteStartOfMarkHRClosure startcl; | |
| 811 g1h->heap_region_iterate(&startcl); | |
| 812 | |
| 813 // Start weak-reference discovery. | |
| 814 ReferenceProcessor* rp = g1h->ref_processor(); | |
| 815 rp->verify_no_references_recorded(); | |
| 816 rp->enable_discovery(); // enable ("weak") refs discovery | |
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817 rp->setup_policy(false); // snapshot the soft ref policy to be used in this cycle |
| 342 | 818 |
| 819 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 820 satb_mq_set.set_process_completed_threshold(G1SATBProcessCompletedThreshold); | |
| 821 satb_mq_set.set_active_all_threads(true); | |
| 822 | |
| 823 // update_g1_committed() will be called at the end of an evac pause | |
| 824 // when marking is on. So, it's also called at the end of the | |
| 825 // initial-mark pause to update the heap end, if the heap expands | |
| 826 // during it. No need to call it here. | |
| 827 | |
| 828 guarantee( !_cleanup_co_tracker.enabled(), "invariant" ); | |
| 829 | |
| 830 size_t max_marking_threads = | |
| 831 MAX2((size_t) 1, parallel_marking_threads()); | |
| 832 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 833 _tasks[i]->enable_co_tracker(); | |
| 834 if (i < (int) max_marking_threads) | |
| 835 _tasks[i]->reset_co_tracker(marking_task_overhead()); | |
| 836 else | |
| 837 _tasks[i]->reset_co_tracker(0.0); | |
| 838 } | |
| 839 } | |
| 840 | |
| 841 // Checkpoint the roots into this generation from outside | |
| 842 // this generation. [Note this initial checkpoint need only | |
| 843 // be approximate -- we'll do a catch up phase subsequently.] | |
| 844 void ConcurrentMark::checkpointRootsInitial() { | |
| 845 assert(SafepointSynchronize::is_at_safepoint(), "world should be stopped"); | |
| 846 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 847 | |
| 848 double start = os::elapsedTime(); | |
| 849 GCOverheadReporter::recordSTWStart(start); | |
| 850 | |
| 851 G1CollectorPolicy* g1p = G1CollectedHeap::heap()->g1_policy(); | |
| 852 g1p->record_concurrent_mark_init_start(); | |
| 853 checkpointRootsInitialPre(); | |
| 854 | |
| 855 // YSR: when concurrent precleaning is in place, we'll | |
| 856 // need to clear the cached card table here | |
| 857 | |
| 858 ResourceMark rm; | |
| 859 HandleMark hm; | |
| 860 | |
| 861 g1h->ensure_parsability(false); | |
| 862 g1h->perm_gen()->save_marks(); | |
| 863 | |
| 864 CMMarkRootsClosure notOlder(this, g1h, false); | |
| 865 CMMarkRootsClosure older(this, g1h, true); | |
| 866 | |
| 867 g1h->set_marking_started(); | |
| 868 g1h->rem_set()->prepare_for_younger_refs_iterate(false); | |
| 869 | |
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870 g1h->process_strong_roots(true, // activate StrongRootsScope |
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871 false, // fake perm gen collection |
| 342 | 872 SharedHeap::SO_AllClasses, |
| 873 ¬Older, // Regular roots | |
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874 NULL, // do not visit active blobs |
| 342 | 875 &older // Perm Gen Roots |
| 876 ); | |
| 877 checkpointRootsInitialPost(); | |
| 878 | |
| 879 // Statistics. | |
| 880 double end = os::elapsedTime(); | |
| 881 _init_times.add((end - start) * 1000.0); | |
| 882 GCOverheadReporter::recordSTWEnd(end); | |
| 883 | |
| 884 g1p->record_concurrent_mark_init_end(); | |
| 885 } | |
| 886 | |
| 887 /* | |
| 888 Notice that in the next two methods, we actually leave the STS | |
| 889 during the barrier sync and join it immediately afterwards. If we | |
| 890 do not do this, this then the following deadlock can occur: one | |
| 891 thread could be in the barrier sync code, waiting for the other | |
| 892 thread to also sync up, whereas another one could be trying to | |
| 893 yield, while also waiting for the other threads to sync up too. | |
| 894 | |
| 895 Because the thread that does the sync barrier has left the STS, it | |
| 896 is possible to be suspended for a Full GC or an evacuation pause | |
| 897 could occur. This is actually safe, since the entering the sync | |
| 898 barrier is one of the last things do_marking_step() does, and it | |
| 899 doesn't manipulate any data structures afterwards. | |
| 900 */ | |
| 901 | |
| 902 void ConcurrentMark::enter_first_sync_barrier(int task_num) { | |
| 903 if (verbose_low()) | |
| 904 gclog_or_tty->print_cr("[%d] entering first barrier", task_num); | |
| 905 | |
| 906 ConcurrentGCThread::stsLeave(); | |
| 907 _first_overflow_barrier_sync.enter(); | |
| 908 ConcurrentGCThread::stsJoin(); | |
| 909 // at this point everyone should have synced up and not be doing any | |
| 910 // more work | |
| 911 | |
| 912 if (verbose_low()) | |
| 913 gclog_or_tty->print_cr("[%d] leaving first barrier", task_num); | |
| 914 | |
| 915 // let task 0 do this | |
| 916 if (task_num == 0) { | |
| 917 // task 0 is responsible for clearing the global data structures | |
| 918 clear_marking_state(); | |
| 919 | |
| 920 if (PrintGC) { | |
| 921 gclog_or_tty->date_stamp(PrintGCDateStamps); | |
| 922 gclog_or_tty->stamp(PrintGCTimeStamps); | |
| 923 gclog_or_tty->print_cr("[GC concurrent-mark-reset-for-overflow]"); | |
| 924 } | |
| 925 } | |
| 926 | |
| 927 // after this, each task should reset its own data structures then | |
| 928 // then go into the second barrier | |
| 929 } | |
| 930 | |
| 931 void ConcurrentMark::enter_second_sync_barrier(int task_num) { | |
| 932 if (verbose_low()) | |
| 933 gclog_or_tty->print_cr("[%d] entering second barrier", task_num); | |
| 934 | |
| 935 ConcurrentGCThread::stsLeave(); | |
| 936 _second_overflow_barrier_sync.enter(); | |
| 937 ConcurrentGCThread::stsJoin(); | |
| 938 // at this point everything should be re-initialised and ready to go | |
| 939 | |
| 940 if (verbose_low()) | |
| 941 gclog_or_tty->print_cr("[%d] leaving second barrier", task_num); | |
| 942 } | |
| 943 | |
| 944 void ConcurrentMark::grayRoot(oop p) { | |
| 945 HeapWord* addr = (HeapWord*) p; | |
| 946 // We can't really check against _heap_start and _heap_end, since it | |
| 947 // is possible during an evacuation pause with piggy-backed | |
| 948 // initial-mark that the committed space is expanded during the | |
| 949 // pause without CM observing this change. So the assertions below | |
| 950 // is a bit conservative; but better than nothing. | |
| 951 tmp_guarantee_CM( _g1h->g1_committed().contains(addr), | |
| 952 "address should be within the heap bounds" ); | |
| 953 | |
| 954 if (!_nextMarkBitMap->isMarked(addr)) | |
| 955 _nextMarkBitMap->parMark(addr); | |
| 956 } | |
| 957 | |
| 958 void ConcurrentMark::grayRegionIfNecessary(MemRegion mr) { | |
| 959 // The objects on the region have already been marked "in bulk" by | |
| 960 // the caller. We only need to decide whether to push the region on | |
| 961 // the region stack or not. | |
| 962 | |
| 963 if (!concurrent_marking_in_progress() || !_should_gray_objects) | |
| 964 // We're done with marking and waiting for remark. We do not need to | |
| 965 // push anything else on the region stack. | |
| 966 return; | |
| 967 | |
| 968 HeapWord* finger = _finger; | |
| 969 | |
| 970 if (verbose_low()) | |
| 971 gclog_or_tty->print_cr("[global] attempting to push " | |
| 972 "region ["PTR_FORMAT", "PTR_FORMAT"), finger is at " | |
| 973 PTR_FORMAT, mr.start(), mr.end(), finger); | |
| 974 | |
| 975 if (mr.start() < finger) { | |
| 976 // The finger is always heap region aligned and it is not possible | |
| 977 // for mr to span heap regions. | |
| 978 tmp_guarantee_CM( mr.end() <= finger, "invariant" ); | |
| 979 | |
| 980 tmp_guarantee_CM( mr.start() <= mr.end() && | |
| 981 _heap_start <= mr.start() && | |
| 982 mr.end() <= _heap_end, | |
| 983 "region boundaries should fall within the committed space" ); | |
| 984 if (verbose_low()) | |
| 985 gclog_or_tty->print_cr("[global] region ["PTR_FORMAT", "PTR_FORMAT") " | |
| 986 "below the finger, pushing it", | |
| 987 mr.start(), mr.end()); | |
| 988 | |
| 989 if (!region_stack_push(mr)) { | |
| 990 if (verbose_low()) | |
| 991 gclog_or_tty->print_cr("[global] region stack has overflown."); | |
| 992 } | |
| 993 } | |
| 994 } | |
| 995 | |
| 996 void ConcurrentMark::markAndGrayObjectIfNecessary(oop p) { | |
| 997 // The object is not marked by the caller. We need to at least mark | |
| 998 // it and maybe push in on the stack. | |
| 999 | |
| 1000 HeapWord* addr = (HeapWord*)p; | |
| 1001 if (!_nextMarkBitMap->isMarked(addr)) { | |
| 1002 // We definitely need to mark it, irrespective whether we bail out | |
| 1003 // because we're done with marking. | |
| 1004 if (_nextMarkBitMap->parMark(addr)) { | |
| 1005 if (!concurrent_marking_in_progress() || !_should_gray_objects) | |
| 1006 // If we're done with concurrent marking and we're waiting for | |
| 1007 // remark, then we're not pushing anything on the stack. | |
| 1008 return; | |
| 1009 | |
| 1010 // No OrderAccess:store_load() is needed. It is implicit in the | |
| 1011 // CAS done in parMark(addr) above | |
| 1012 HeapWord* finger = _finger; | |
| 1013 | |
| 1014 if (addr < finger) { | |
| 1015 if (!mark_stack_push(oop(addr))) { | |
| 1016 if (verbose_low()) | |
| 1017 gclog_or_tty->print_cr("[global] global stack overflow " | |
| 1018 "during parMark"); | |
| 1019 } | |
| 1020 } | |
| 1021 } | |
| 1022 } | |
| 1023 } | |
| 1024 | |
| 1025 class CMConcurrentMarkingTask: public AbstractGangTask { | |
| 1026 private: | |
| 1027 ConcurrentMark* _cm; | |
| 1028 ConcurrentMarkThread* _cmt; | |
| 1029 | |
| 1030 public: | |
| 1031 void work(int worker_i) { | |
| 1032 guarantee( Thread::current()->is_ConcurrentGC_thread(), | |
| 1033 "this should only be done by a conc GC thread" ); | |
| 1034 | |
| 1035 double start_vtime = os::elapsedVTime(); | |
| 1036 | |
| 1037 ConcurrentGCThread::stsJoin(); | |
| 1038 | |
| 1039 guarantee( (size_t)worker_i < _cm->active_tasks(), "invariant" ); | |
| 1040 CMTask* the_task = _cm->task(worker_i); | |
| 1041 the_task->start_co_tracker(); | |
| 1042 the_task->record_start_time(); | |
| 1043 if (!_cm->has_aborted()) { | |
| 1044 do { | |
| 1045 double start_vtime_sec = os::elapsedVTime(); | |
| 1046 double start_time_sec = os::elapsedTime(); | |
| 1047 the_task->do_marking_step(10.0); | |
| 1048 double end_time_sec = os::elapsedTime(); | |
| 1049 double end_vtime_sec = os::elapsedVTime(); | |
| 1050 double elapsed_vtime_sec = end_vtime_sec - start_vtime_sec; | |
| 1051 double elapsed_time_sec = end_time_sec - start_time_sec; | |
| 1052 _cm->clear_has_overflown(); | |
| 1053 | |
| 1054 bool ret = _cm->do_yield_check(worker_i); | |
| 1055 | |
| 1056 jlong sleep_time_ms; | |
| 1057 if (!_cm->has_aborted() && the_task->has_aborted()) { | |
| 1058 sleep_time_ms = | |
| 1059 (jlong) (elapsed_vtime_sec * _cm->sleep_factor() * 1000.0); | |
| 1060 ConcurrentGCThread::stsLeave(); | |
| 1061 os::sleep(Thread::current(), sleep_time_ms, false); | |
| 1062 ConcurrentGCThread::stsJoin(); | |
| 1063 } | |
| 1064 double end_time2_sec = os::elapsedTime(); | |
| 1065 double elapsed_time2_sec = end_time2_sec - start_time_sec; | |
| 1066 | |
| 1067 the_task->update_co_tracker(); | |
| 1068 | |
| 1069 #if 0 | |
| 1070 gclog_or_tty->print_cr("CM: elapsed %1.4lf ms, sleep %1.4lf ms, " | |
| 1071 "overhead %1.4lf", | |
| 1072 elapsed_vtime_sec * 1000.0, (double) sleep_time_ms, | |
| 1073 the_task->conc_overhead(os::elapsedTime()) * 8.0); | |
| 1074 gclog_or_tty->print_cr("elapsed time %1.4lf ms, time 2: %1.4lf ms", | |
| 1075 elapsed_time_sec * 1000.0, elapsed_time2_sec * 1000.0); | |
| 1076 #endif | |
| 1077 } while (!_cm->has_aborted() && the_task->has_aborted()); | |
| 1078 } | |
| 1079 the_task->record_end_time(); | |
| 1080 guarantee( !the_task->has_aborted() || _cm->has_aborted(), "invariant" ); | |
| 1081 | |
| 1082 ConcurrentGCThread::stsLeave(); | |
| 1083 | |
| 1084 double end_vtime = os::elapsedVTime(); | |
| 1085 the_task->update_co_tracker(true); | |
| 1086 _cm->update_accum_task_vtime(worker_i, end_vtime - start_vtime); | |
| 1087 } | |
| 1088 | |
| 1089 CMConcurrentMarkingTask(ConcurrentMark* cm, | |
| 1090 ConcurrentMarkThread* cmt) : | |
| 1091 AbstractGangTask("Concurrent Mark"), _cm(cm), _cmt(cmt) { } | |
| 1092 | |
| 1093 ~CMConcurrentMarkingTask() { } | |
| 1094 }; | |
| 1095 | |
| 1096 void ConcurrentMark::markFromRoots() { | |
| 1097 // we might be tempted to assert that: | |
| 1098 // assert(asynch == !SafepointSynchronize::is_at_safepoint(), | |
| 1099 // "inconsistent argument?"); | |
| 1100 // However that wouldn't be right, because it's possible that | |
| 1101 // a safepoint is indeed in progress as a younger generation | |
| 1102 // stop-the-world GC happens even as we mark in this generation. | |
| 1103 | |
| 1104 _restart_for_overflow = false; | |
| 1105 | |
| 1106 set_phase(MAX2((size_t) 1, parallel_marking_threads()), true); | |
| 1107 | |
| 1108 CMConcurrentMarkingTask markingTask(this, cmThread()); | |
| 1109 if (parallel_marking_threads() > 0) | |
| 1110 _parallel_workers->run_task(&markingTask); | |
| 1111 else | |
| 1112 markingTask.work(0); | |
| 1113 print_stats(); | |
| 1114 } | |
| 1115 | |
| 1116 void ConcurrentMark::checkpointRootsFinal(bool clear_all_soft_refs) { | |
| 1117 // world is stopped at this checkpoint | |
| 1118 assert(SafepointSynchronize::is_at_safepoint(), | |
| 1119 "world should be stopped"); | |
| 1120 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1121 | |
| 1122 // If a full collection has happened, we shouldn't do this. | |
| 1123 if (has_aborted()) { | |
| 1124 g1h->set_marking_complete(); // So bitmap clearing isn't confused | |
| 1125 return; | |
| 1126 } | |
| 1127 | |
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1128 if (VerifyDuringGC) { |
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1129 HandleMark hm; // handle scope |
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1130 gclog_or_tty->print(" VerifyDuringGC:(before)"); |
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1131 Universe::heap()->prepare_for_verify(); |
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1132 Universe::verify(true, false, true); |
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1133 } |
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1134 |
| 342 | 1135 G1CollectorPolicy* g1p = g1h->g1_policy(); |
| 1136 g1p->record_concurrent_mark_remark_start(); | |
| 1137 | |
| 1138 double start = os::elapsedTime(); | |
| 1139 GCOverheadReporter::recordSTWStart(start); | |
| 1140 | |
| 1141 checkpointRootsFinalWork(); | |
| 1142 | |
| 1143 double mark_work_end = os::elapsedTime(); | |
| 1144 | |
| 1145 weakRefsWork(clear_all_soft_refs); | |
| 1146 | |
| 1147 if (has_overflown()) { | |
| 1148 // Oops. We overflowed. Restart concurrent marking. | |
| 1149 _restart_for_overflow = true; | |
| 1150 // Clear the flag. We do not need it any more. | |
| 1151 clear_has_overflown(); | |
| 1152 if (G1TraceMarkStackOverflow) | |
| 1153 gclog_or_tty->print_cr("\nRemark led to restart for overflow."); | |
| 1154 } else { | |
| 1155 // We're done with marking. | |
| 1156 JavaThread::satb_mark_queue_set().set_active_all_threads(false); | |
| 811 | 1157 |
| 1158 if (VerifyDuringGC) { | |
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1159 HandleMark hm; // handle scope |
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1160 gclog_or_tty->print(" VerifyDuringGC:(after)"); |
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1161 Universe::heap()->prepare_for_verify(); |
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1162 Universe::heap()->verify(/* allow_dirty */ true, |
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1163 /* silent */ false, |
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1164 /* use_prev_marking */ false); |
| 811 | 1165 } |
| 342 | 1166 } |
| 1167 | |
| 1168 #if VERIFY_OBJS_PROCESSED | |
| 1169 _scan_obj_cl.objs_processed = 0; | |
| 1170 ThreadLocalObjQueue::objs_enqueued = 0; | |
| 1171 #endif | |
| 1172 | |
| 1173 // Statistics | |
| 1174 double now = os::elapsedTime(); | |
| 1175 _remark_mark_times.add((mark_work_end - start) * 1000.0); | |
| 1176 _remark_weak_ref_times.add((now - mark_work_end) * 1000.0); | |
| 1177 _remark_times.add((now - start) * 1000.0); | |
| 1178 | |
| 1179 GCOverheadReporter::recordSTWEnd(now); | |
| 1180 for (int i = 0; i < (int)_max_task_num; ++i) | |
| 1181 _tasks[i]->disable_co_tracker(); | |
| 1182 _cleanup_co_tracker.enable(); | |
| 1183 _cleanup_co_tracker.reset(cleanup_task_overhead()); | |
| 1184 g1p->record_concurrent_mark_remark_end(); | |
| 1185 } | |
| 1186 | |
| 1187 | |
| 1188 #define CARD_BM_TEST_MODE 0 | |
| 1189 | |
| 1190 class CalcLiveObjectsClosure: public HeapRegionClosure { | |
| 1191 | |
| 1192 CMBitMapRO* _bm; | |
| 1193 ConcurrentMark* _cm; | |
| 1194 COTracker* _co_tracker; | |
| 1195 bool _changed; | |
| 1196 bool _yield; | |
| 1197 size_t _words_done; | |
| 1198 size_t _tot_live; | |
| 1199 size_t _tot_used; | |
| 1200 size_t _regions_done; | |
| 1201 double _start_vtime_sec; | |
| 1202 | |
| 1203 BitMap* _region_bm; | |
| 1204 BitMap* _card_bm; | |
| 1205 intptr_t _bottom_card_num; | |
| 1206 bool _final; | |
| 1207 | |
| 1208 void mark_card_num_range(intptr_t start_card_num, intptr_t last_card_num) { | |
| 1209 for (intptr_t i = start_card_num; i <= last_card_num; i++) { | |
| 1210 #if CARD_BM_TEST_MODE | |
| 1211 guarantee(_card_bm->at(i - _bottom_card_num), | |
| 1212 "Should already be set."); | |
| 1213 #else | |
| 1214 _card_bm->par_at_put(i - _bottom_card_num, 1); | |
| 1215 #endif | |
| 1216 } | |
| 1217 } | |
| 1218 | |
| 1219 public: | |
| 1220 CalcLiveObjectsClosure(bool final, | |
| 1221 CMBitMapRO *bm, ConcurrentMark *cm, | |
| 1222 BitMap* region_bm, BitMap* card_bm, | |
| 1223 COTracker* co_tracker) : | |
| 1224 _bm(bm), _cm(cm), _changed(false), _yield(true), | |
| 1225 _words_done(0), _tot_live(0), _tot_used(0), | |
| 1226 _region_bm(region_bm), _card_bm(card_bm), | |
| 1227 _final(final), _co_tracker(co_tracker), | |
| 1228 _regions_done(0), _start_vtime_sec(0.0) | |
| 1229 { | |
| 1230 _bottom_card_num = | |
| 1231 intptr_t(uintptr_t(G1CollectedHeap::heap()->reserved_region().start()) >> | |
| 1232 CardTableModRefBS::card_shift); | |
| 1233 } | |
| 1234 | |
| 829 | 1235 // It takes a region that's not empty (i.e., it has at least one |
| 1236 // live object in it and sets its corresponding bit on the region | |
| 1237 // bitmap to 1. If the region is "starts humongous" it will also set | |
| 1238 // to 1 the bits on the region bitmap that correspond to its | |
| 1239 // associated "continues humongous" regions. | |
| 1240 void set_bit_for_region(HeapRegion* hr) { | |
| 1241 assert(!hr->continuesHumongous(), "should have filtered those out"); | |
| 1242 | |
| 1243 size_t index = hr->hrs_index(); | |
| 1244 if (!hr->startsHumongous()) { | |
| 1245 // Normal (non-humongous) case: just set the bit. | |
| 1246 _region_bm->par_at_put((BitMap::idx_t) index, true); | |
| 1247 } else { | |
| 1248 // Starts humongous case: calculate how many regions are part of | |
| 1249 // this humongous region and then set the bit range. It might | |
| 1250 // have been a bit more efficient to look at the object that | |
| 1251 // spans these humongous regions to calculate their number from | |
| 1252 // the object's size. However, it's a good idea to calculate | |
| 1253 // this based on the metadata itself, and not the region | |
| 1254 // contents, so that this code is not aware of what goes into | |
| 1255 // the humongous regions (in case this changes in the future). | |
| 1256 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1257 size_t end_index = index + 1; | |
| 831 | 1258 while (end_index < g1h->n_regions()) { |
| 1259 HeapRegion* chr = g1h->region_at(end_index); | |
| 829 | 1260 if (!chr->continuesHumongous()) { |
| 1261 break; | |
| 1262 } | |
| 1263 end_index += 1; | |
| 1264 } | |
| 1265 _region_bm->par_at_put_range((BitMap::idx_t) index, | |
| 1266 (BitMap::idx_t) end_index, true); | |
| 1267 } | |
| 1268 } | |
| 1269 | |
| 342 | 1270 bool doHeapRegion(HeapRegion* hr) { |
| 1271 if (_co_tracker != NULL) | |
| 1272 _co_tracker->update(); | |
| 1273 | |
| 1274 if (!_final && _regions_done == 0) | |
| 1275 _start_vtime_sec = os::elapsedVTime(); | |
| 1276 | |
| 639 | 1277 if (hr->continuesHumongous()) { |
| 829 | 1278 // We will ignore these here and process them when their |
| 1279 // associated "starts humongous" region is processed (see | |
| 1280 // set_bit_for_heap_region()). Note that we cannot rely on their | |
| 1281 // associated "starts humongous" region to have their bit set to | |
| 1282 // 1 since, due to the region chunking in the parallel region | |
| 1283 // iteration, a "continues humongous" region might be visited | |
| 1284 // before its associated "starts humongous". | |
| 639 | 1285 return false; |
| 1286 } | |
| 342 | 1287 |
| 1288 HeapWord* nextTop = hr->next_top_at_mark_start(); | |
| 1289 HeapWord* start = hr->top_at_conc_mark_count(); | |
| 1290 assert(hr->bottom() <= start && start <= hr->end() && | |
| 1291 hr->bottom() <= nextTop && nextTop <= hr->end() && | |
| 1292 start <= nextTop, | |
| 1293 "Preconditions."); | |
| 1294 // Otherwise, record the number of word's we'll examine. | |
| 1295 size_t words_done = (nextTop - start); | |
| 1296 // Find the first marked object at or after "start". | |
| 1297 start = _bm->getNextMarkedWordAddress(start, nextTop); | |
| 1298 size_t marked_bytes = 0; | |
| 1299 | |
| 1300 // Below, the term "card num" means the result of shifting an address | |
| 1301 // by the card shift -- address 0 corresponds to card number 0. One | |
| 1302 // must subtract the card num of the bottom of the heap to obtain a | |
| 1303 // card table index. | |
| 1304 // The first card num of the sequence of live cards currently being | |
| 1305 // constructed. -1 ==> no sequence. | |
| 1306 intptr_t start_card_num = -1; | |
| 1307 // The last card num of the sequence of live cards currently being | |
| 1308 // constructed. -1 ==> no sequence. | |
| 1309 intptr_t last_card_num = -1; | |
| 1310 | |
| 1311 while (start < nextTop) { | |
| 1312 if (_yield && _cm->do_yield_check()) { | |
| 1313 // We yielded. It might be for a full collection, in which case | |
| 1314 // all bets are off; terminate the traversal. | |
| 1315 if (_cm->has_aborted()) { | |
| 1316 _changed = false; | |
| 1317 return true; | |
| 1318 } else { | |
| 1319 // Otherwise, it might be a collection pause, and the region | |
| 1320 // we're looking at might be in the collection set. We'll | |
| 1321 // abandon this region. | |
| 1322 return false; | |
| 1323 } | |
| 1324 } | |
| 1325 oop obj = oop(start); | |
| 1326 int obj_sz = obj->size(); | |
| 1327 // The card num of the start of the current object. | |
| 1328 intptr_t obj_card_num = | |
| 1329 intptr_t(uintptr_t(start) >> CardTableModRefBS::card_shift); | |
| 1330 | |
| 1331 HeapWord* obj_last = start + obj_sz - 1; | |
| 1332 intptr_t obj_last_card_num = | |
| 1333 intptr_t(uintptr_t(obj_last) >> CardTableModRefBS::card_shift); | |
| 1334 | |
| 1335 if (obj_card_num != last_card_num) { | |
| 1336 if (start_card_num == -1) { | |
| 1337 assert(last_card_num == -1, "Both or neither."); | |
| 1338 start_card_num = obj_card_num; | |
| 1339 } else { | |
| 1340 assert(last_card_num != -1, "Both or neither."); | |
| 1341 assert(obj_card_num >= last_card_num, "Inv"); | |
| 1342 if ((obj_card_num - last_card_num) > 1) { | |
| 1343 // Mark the last run, and start a new one. | |
| 1344 mark_card_num_range(start_card_num, last_card_num); | |
| 1345 start_card_num = obj_card_num; | |
| 1346 } | |
| 1347 } | |
| 1348 #if CARD_BM_TEST_MODE | |
| 1349 /* | |
| 1350 gclog_or_tty->print_cr("Setting bits from %d/%d.", | |
| 1351 obj_card_num - _bottom_card_num, | |
| 1352 obj_last_card_num - _bottom_card_num); | |
| 1353 */ | |
| 1354 for (intptr_t j = obj_card_num; j <= obj_last_card_num; j++) { | |
| 1355 _card_bm->par_at_put(j - _bottom_card_num, 1); | |
| 1356 } | |
| 1357 #endif | |
| 1358 } | |
| 1359 // In any case, we set the last card num. | |
| 1360 last_card_num = obj_last_card_num; | |
| 1361 | |
| 1362 marked_bytes += obj_sz * HeapWordSize; | |
| 1363 // Find the next marked object after this one. | |
| 1364 start = _bm->getNextMarkedWordAddress(start + 1, nextTop); | |
| 1365 _changed = true; | |
| 1366 } | |
| 1367 // Handle the last range, if any. | |
| 1368 if (start_card_num != -1) | |
| 1369 mark_card_num_range(start_card_num, last_card_num); | |
| 1370 if (_final) { | |
| 1371 // Mark the allocated-since-marking portion... | |
| 1372 HeapWord* tp = hr->top(); | |
| 1373 if (nextTop < tp) { | |
| 1374 start_card_num = | |
| 1375 intptr_t(uintptr_t(nextTop) >> CardTableModRefBS::card_shift); | |
| 1376 last_card_num = | |
| 1377 intptr_t(uintptr_t(tp) >> CardTableModRefBS::card_shift); | |
| 1378 mark_card_num_range(start_card_num, last_card_num); | |
| 1379 // This definitely means the region has live objects. | |
| 829 | 1380 set_bit_for_region(hr); |
| 342 | 1381 } |
| 1382 } | |
| 1383 | |
| 1384 hr->add_to_marked_bytes(marked_bytes); | |
| 1385 // Update the live region bitmap. | |
| 1386 if (marked_bytes > 0) { | |
| 829 | 1387 set_bit_for_region(hr); |
| 342 | 1388 } |
| 1389 hr->set_top_at_conc_mark_count(nextTop); | |
| 1390 _tot_live += hr->next_live_bytes(); | |
| 1391 _tot_used += hr->used(); | |
| 1392 _words_done = words_done; | |
| 1393 | |
| 1394 if (!_final) { | |
| 1395 ++_regions_done; | |
| 1396 if (_regions_done % 10 == 0) { | |
| 1397 double end_vtime_sec = os::elapsedVTime(); | |
| 1398 double elapsed_vtime_sec = end_vtime_sec - _start_vtime_sec; | |
| 1399 if (elapsed_vtime_sec > (10.0 / 1000.0)) { | |
| 1400 jlong sleep_time_ms = | |
| 1401 (jlong) (elapsed_vtime_sec * _cm->cleanup_sleep_factor() * 1000.0); | |
| 1402 #if 0 | |
| 1403 gclog_or_tty->print_cr("CL: elapsed %1.4lf ms, sleep %1.4lf ms, " | |
| 1404 "overhead %1.4lf", | |
| 1405 elapsed_vtime_sec * 1000.0, (double) sleep_time_ms, | |
| 1406 _co_tracker->concOverhead(os::elapsedTime())); | |
| 1407 #endif | |
| 1408 os::sleep(Thread::current(), sleep_time_ms, false); | |
| 1409 _start_vtime_sec = end_vtime_sec; | |
| 1410 } | |
| 1411 } | |
| 1412 } | |
| 1413 | |
| 1414 return false; | |
| 1415 } | |
| 1416 | |
| 1417 bool changed() { return _changed; } | |
| 1418 void reset() { _changed = false; _words_done = 0; } | |
| 1419 void no_yield() { _yield = false; } | |
| 1420 size_t words_done() { return _words_done; } | |
| 1421 size_t tot_live() { return _tot_live; } | |
| 1422 size_t tot_used() { return _tot_used; } | |
| 1423 }; | |
| 1424 | |
| 1425 | |
| 1426 void ConcurrentMark::calcDesiredRegions() { | |
| 1427 guarantee( _cleanup_co_tracker.enabled(), "invariant" ); | |
| 1428 _cleanup_co_tracker.start(); | |
| 1429 | |
| 1430 _region_bm.clear(); | |
| 1431 _card_bm.clear(); | |
| 1432 CalcLiveObjectsClosure calccl(false /*final*/, | |
| 1433 nextMarkBitMap(), this, | |
| 1434 &_region_bm, &_card_bm, | |
| 1435 &_cleanup_co_tracker); | |
| 1436 G1CollectedHeap *g1h = G1CollectedHeap::heap(); | |
| 1437 g1h->heap_region_iterate(&calccl); | |
| 1438 | |
| 1439 do { | |
| 1440 calccl.reset(); | |
| 1441 g1h->heap_region_iterate(&calccl); | |
| 1442 } while (calccl.changed()); | |
| 1443 | |
| 1444 _cleanup_co_tracker.update(true); | |
| 1445 } | |
| 1446 | |
| 1447 class G1ParFinalCountTask: public AbstractGangTask { | |
| 1448 protected: | |
| 1449 G1CollectedHeap* _g1h; | |
| 1450 CMBitMap* _bm; | |
| 1451 size_t _n_workers; | |
| 1452 size_t *_live_bytes; | |
| 1453 size_t *_used_bytes; | |
| 1454 BitMap* _region_bm; | |
| 1455 BitMap* _card_bm; | |
| 1456 public: | |
| 1457 G1ParFinalCountTask(G1CollectedHeap* g1h, CMBitMap* bm, | |
| 1458 BitMap* region_bm, BitMap* card_bm) : | |
| 1459 AbstractGangTask("G1 final counting"), _g1h(g1h), | |
| 1460 _bm(bm), _region_bm(region_bm), _card_bm(card_bm) | |
| 1461 { | |
| 1462 if (ParallelGCThreads > 0) | |
| 1463 _n_workers = _g1h->workers()->total_workers(); | |
| 1464 else | |
| 1465 _n_workers = 1; | |
| 1466 _live_bytes = NEW_C_HEAP_ARRAY(size_t, _n_workers); | |
| 1467 _used_bytes = NEW_C_HEAP_ARRAY(size_t, _n_workers); | |
| 1468 } | |
| 1469 | |
| 1470 ~G1ParFinalCountTask() { | |
| 1471 FREE_C_HEAP_ARRAY(size_t, _live_bytes); | |
| 1472 FREE_C_HEAP_ARRAY(size_t, _used_bytes); | |
| 1473 } | |
| 1474 | |
| 1475 void work(int i) { | |
| 1476 CalcLiveObjectsClosure calccl(true /*final*/, | |
| 1477 _bm, _g1h->concurrent_mark(), | |
| 1478 _region_bm, _card_bm, | |
| 1479 NULL /* CO tracker */); | |
| 1480 calccl.no_yield(); | |
| 1481 if (ParallelGCThreads > 0) { | |
| 355 | 1482 _g1h->heap_region_par_iterate_chunked(&calccl, i, |
| 1483 HeapRegion::FinalCountClaimValue); | |
| 342 | 1484 } else { |
| 1485 _g1h->heap_region_iterate(&calccl); | |
| 1486 } | |
| 1487 assert(calccl.complete(), "Shouldn't have yielded!"); | |
| 1488 | |
| 1489 guarantee( (size_t)i < _n_workers, "invariant" ); | |
| 1490 _live_bytes[i] = calccl.tot_live(); | |
| 1491 _used_bytes[i] = calccl.tot_used(); | |
| 1492 } | |
| 1493 size_t live_bytes() { | |
| 1494 size_t live_bytes = 0; | |
| 1495 for (size_t i = 0; i < _n_workers; ++i) | |
| 1496 live_bytes += _live_bytes[i]; | |
| 1497 return live_bytes; | |
| 1498 } | |
| 1499 size_t used_bytes() { | |
| 1500 size_t used_bytes = 0; | |
| 1501 for (size_t i = 0; i < _n_workers; ++i) | |
| 1502 used_bytes += _used_bytes[i]; | |
| 1503 return used_bytes; | |
| 1504 } | |
| 1505 }; | |
| 1506 | |
| 1507 class G1ParNoteEndTask; | |
| 1508 | |
| 1509 class G1NoteEndOfConcMarkClosure : public HeapRegionClosure { | |
| 1510 G1CollectedHeap* _g1; | |
| 1511 int _worker_num; | |
| 1512 size_t _max_live_bytes; | |
| 1513 size_t _regions_claimed; | |
| 1514 size_t _freed_bytes; | |
| 1515 size_t _cleared_h_regions; | |
| 1516 size_t _freed_regions; | |
| 1517 UncleanRegionList* _unclean_region_list; | |
| 1518 double _claimed_region_time; | |
| 1519 double _max_region_time; | |
| 1520 | |
| 1521 public: | |
| 1522 G1NoteEndOfConcMarkClosure(G1CollectedHeap* g1, | |
| 1523 UncleanRegionList* list, | |
| 1524 int worker_num); | |
| 1525 size_t freed_bytes() { return _freed_bytes; } | |
| 1526 size_t cleared_h_regions() { return _cleared_h_regions; } | |
| 1527 size_t freed_regions() { return _freed_regions; } | |
| 1528 UncleanRegionList* unclean_region_list() { | |
| 1529 return _unclean_region_list; | |
| 1530 } | |
| 1531 | |
| 1532 bool doHeapRegion(HeapRegion *r); | |
| 1533 | |
| 1534 size_t max_live_bytes() { return _max_live_bytes; } | |
| 1535 size_t regions_claimed() { return _regions_claimed; } | |
| 1536 double claimed_region_time_sec() { return _claimed_region_time; } | |
| 1537 double max_region_time_sec() { return _max_region_time; } | |
| 1538 }; | |
| 1539 | |
| 1540 class G1ParNoteEndTask: public AbstractGangTask { | |
| 1541 friend class G1NoteEndOfConcMarkClosure; | |
| 1542 protected: | |
| 1543 G1CollectedHeap* _g1h; | |
| 1544 size_t _max_live_bytes; | |
| 1545 size_t _freed_bytes; | |
| 1546 ConcurrentMark::ParCleanupThreadState** _par_cleanup_thread_state; | |
| 1547 public: | |
| 1548 G1ParNoteEndTask(G1CollectedHeap* g1h, | |
| 1549 ConcurrentMark::ParCleanupThreadState** | |
| 1550 par_cleanup_thread_state) : | |
| 1551 AbstractGangTask("G1 note end"), _g1h(g1h), | |
| 1552 _max_live_bytes(0), _freed_bytes(0), | |
| 1553 _par_cleanup_thread_state(par_cleanup_thread_state) | |
| 1554 {} | |
| 1555 | |
| 1556 void work(int i) { | |
| 1557 double start = os::elapsedTime(); | |
| 1558 G1NoteEndOfConcMarkClosure g1_note_end(_g1h, | |
| 1559 &_par_cleanup_thread_state[i]->list, | |
| 1560 i); | |
| 1561 if (ParallelGCThreads > 0) { | |
| 355 | 1562 _g1h->heap_region_par_iterate_chunked(&g1_note_end, i, |
| 1563 HeapRegion::NoteEndClaimValue); | |
| 342 | 1564 } else { |
| 1565 _g1h->heap_region_iterate(&g1_note_end); | |
| 1566 } | |
| 1567 assert(g1_note_end.complete(), "Shouldn't have yielded!"); | |
| 1568 | |
| 1569 // Now finish up freeing the current thread's regions. | |
| 1570 _g1h->finish_free_region_work(g1_note_end.freed_bytes(), | |
| 1571 g1_note_end.cleared_h_regions(), | |
| 1572 0, NULL); | |
| 1573 { | |
| 1574 MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag); | |
| 1575 _max_live_bytes += g1_note_end.max_live_bytes(); | |
| 1576 _freed_bytes += g1_note_end.freed_bytes(); | |
| 1577 } | |
| 1578 double end = os::elapsedTime(); | |
| 1579 if (G1PrintParCleanupStats) { | |
| 1580 gclog_or_tty->print(" Worker thread %d [%8.3f..%8.3f = %8.3f ms] " | |
| 1581 "claimed %d regions (tot = %8.3f ms, max = %8.3f ms).\n", | |
| 1582 i, start, end, (end-start)*1000.0, | |
| 1583 g1_note_end.regions_claimed(), | |
| 1584 g1_note_end.claimed_region_time_sec()*1000.0, | |
| 1585 g1_note_end.max_region_time_sec()*1000.0); | |
| 1586 } | |
| 1587 } | |
| 1588 size_t max_live_bytes() { return _max_live_bytes; } | |
| 1589 size_t freed_bytes() { return _freed_bytes; } | |
| 1590 }; | |
| 1591 | |
| 1592 class G1ParScrubRemSetTask: public AbstractGangTask { | |
| 1593 protected: | |
| 1594 G1RemSet* _g1rs; | |
| 1595 BitMap* _region_bm; | |
| 1596 BitMap* _card_bm; | |
| 1597 public: | |
| 1598 G1ParScrubRemSetTask(G1CollectedHeap* g1h, | |
| 1599 BitMap* region_bm, BitMap* card_bm) : | |
| 1600 AbstractGangTask("G1 ScrubRS"), _g1rs(g1h->g1_rem_set()), | |
| 1601 _region_bm(region_bm), _card_bm(card_bm) | |
| 1602 {} | |
| 1603 | |
| 1604 void work(int i) { | |
| 1605 if (ParallelGCThreads > 0) { | |
| 355 | 1606 _g1rs->scrub_par(_region_bm, _card_bm, i, |
| 1607 HeapRegion::ScrubRemSetClaimValue); | |
| 342 | 1608 } else { |
| 1609 _g1rs->scrub(_region_bm, _card_bm); | |
| 1610 } | |
| 1611 } | |
| 1612 | |
| 1613 }; | |
| 1614 | |
| 1615 G1NoteEndOfConcMarkClosure:: | |
| 1616 G1NoteEndOfConcMarkClosure(G1CollectedHeap* g1, | |
| 1617 UncleanRegionList* list, | |
| 1618 int worker_num) | |
| 1619 : _g1(g1), _worker_num(worker_num), | |
| 1620 _max_live_bytes(0), _regions_claimed(0), | |
| 1621 _freed_bytes(0), _cleared_h_regions(0), _freed_regions(0), | |
| 1622 _claimed_region_time(0.0), _max_region_time(0.0), | |
| 1623 _unclean_region_list(list) | |
| 1624 {} | |
| 1625 | |
| 1626 bool G1NoteEndOfConcMarkClosure::doHeapRegion(HeapRegion *r) { | |
| 1627 // We use a claim value of zero here because all regions | |
| 1628 // were claimed with value 1 in the FinalCount task. | |
| 1629 r->reset_gc_time_stamp(); | |
| 1630 if (!r->continuesHumongous()) { | |
| 1631 double start = os::elapsedTime(); | |
| 1632 _regions_claimed++; | |
| 1633 r->note_end_of_marking(); | |
| 1634 _max_live_bytes += r->max_live_bytes(); | |
| 1635 _g1->free_region_if_totally_empty_work(r, | |
| 1636 _freed_bytes, | |
| 1637 _cleared_h_regions, | |
| 1638 _freed_regions, | |
| 1639 _unclean_region_list, | |
| 1640 true /*par*/); | |
| 1641 double region_time = (os::elapsedTime() - start); | |
| 1642 _claimed_region_time += region_time; | |
| 1643 if (region_time > _max_region_time) _max_region_time = region_time; | |
| 1644 } | |
| 1645 return false; | |
| 1646 } | |
| 1647 | |
| 1648 void ConcurrentMark::cleanup() { | |
| 1649 // world is stopped at this checkpoint | |
| 1650 assert(SafepointSynchronize::is_at_safepoint(), | |
| 1651 "world should be stopped"); | |
| 1652 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1653 | |
| 1654 // If a full collection has happened, we shouldn't do this. | |
| 1655 if (has_aborted()) { | |
| 1656 g1h->set_marking_complete(); // So bitmap clearing isn't confused | |
| 1657 return; | |
| 1658 } | |
| 1659 | |
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1660 if (VerifyDuringGC) { |
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1661 HandleMark hm; // handle scope |
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1662 gclog_or_tty->print(" VerifyDuringGC:(before)"); |
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1663 Universe::heap()->prepare_for_verify(); |
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1664 Universe::verify(/* allow dirty */ true, |
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1665 /* silent */ false, |
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1666 /* prev marking */ true); |
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1667 } |
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1668 |
| 342 | 1669 _cleanup_co_tracker.disable(); |
| 1670 | |
| 1671 G1CollectorPolicy* g1p = G1CollectedHeap::heap()->g1_policy(); | |
| 1672 g1p->record_concurrent_mark_cleanup_start(); | |
| 1673 | |
| 1674 double start = os::elapsedTime(); | |
| 1675 GCOverheadReporter::recordSTWStart(start); | |
| 1676 | |
| 1677 // Do counting once more with the world stopped for good measure. | |
| 1678 G1ParFinalCountTask g1_par_count_task(g1h, nextMarkBitMap(), | |
| 1679 &_region_bm, &_card_bm); | |
| 1680 if (ParallelGCThreads > 0) { | |
| 355 | 1681 assert(g1h->check_heap_region_claim_values( |
| 1682 HeapRegion::InitialClaimValue), | |
| 1683 "sanity check"); | |
| 1684 | |
| 342 | 1685 int n_workers = g1h->workers()->total_workers(); |
| 1686 g1h->set_par_threads(n_workers); | |
| 1687 g1h->workers()->run_task(&g1_par_count_task); | |
| 1688 g1h->set_par_threads(0); | |
| 355 | 1689 |
| 1690 assert(g1h->check_heap_region_claim_values( | |
| 1691 HeapRegion::FinalCountClaimValue), | |
| 1692 "sanity check"); | |
| 342 | 1693 } else { |
| 1694 g1_par_count_task.work(0); | |
| 1695 } | |
| 1696 | |
| 1697 size_t known_garbage_bytes = | |
| 1698 g1_par_count_task.used_bytes() - g1_par_count_task.live_bytes(); | |
| 1699 #if 0 | |
| 1700 gclog_or_tty->print_cr("used %1.2lf, live %1.2lf, garbage %1.2lf", | |
| 1701 (double) g1_par_count_task.used_bytes() / (double) (1024 * 1024), | |
| 1702 (double) g1_par_count_task.live_bytes() / (double) (1024 * 1024), | |
| 1703 (double) known_garbage_bytes / (double) (1024 * 1024)); | |
| 1704 #endif // 0 | |
| 1705 g1p->set_known_garbage_bytes(known_garbage_bytes); | |
| 1706 | |
| 1707 size_t start_used_bytes = g1h->used(); | |
| 1708 _at_least_one_mark_complete = true; | |
| 1709 g1h->set_marking_complete(); | |
| 1710 | |
| 1711 double count_end = os::elapsedTime(); | |
| 1712 double this_final_counting_time = (count_end - start); | |
| 1713 if (G1PrintParCleanupStats) { | |
| 1714 gclog_or_tty->print_cr("Cleanup:"); | |
| 1715 gclog_or_tty->print_cr(" Finalize counting: %8.3f ms", | |
| 1716 this_final_counting_time*1000.0); | |
| 1717 } | |
| 1718 _total_counting_time += this_final_counting_time; | |
| 1719 | |
| 1720 // Install newly created mark bitMap as "prev". | |
| 1721 swapMarkBitMaps(); | |
| 1722 | |
| 1723 g1h->reset_gc_time_stamp(); | |
| 1724 | |
| 1725 // Note end of marking in all heap regions. | |
| 1726 double note_end_start = os::elapsedTime(); | |
| 1727 G1ParNoteEndTask g1_par_note_end_task(g1h, _par_cleanup_thread_state); | |
| 1728 if (ParallelGCThreads > 0) { | |
| 1729 int n_workers = g1h->workers()->total_workers(); | |
| 1730 g1h->set_par_threads(n_workers); | |
| 1731 g1h->workers()->run_task(&g1_par_note_end_task); | |
| 1732 g1h->set_par_threads(0); | |
| 355 | 1733 |
| 1734 assert(g1h->check_heap_region_claim_values(HeapRegion::NoteEndClaimValue), | |
| 1735 "sanity check"); | |
| 342 | 1736 } else { |
| 1737 g1_par_note_end_task.work(0); | |
| 1738 } | |
| 1739 g1h->set_unclean_regions_coming(true); | |
| 1740 double note_end_end = os::elapsedTime(); | |
| 1741 // Tell the mutators that there might be unclean regions coming... | |
| 1742 if (G1PrintParCleanupStats) { | |
| 1743 gclog_or_tty->print_cr(" note end of marking: %8.3f ms.", | |
| 1744 (note_end_end - note_end_start)*1000.0); | |
| 1745 } | |
| 1746 | |
| 355 | 1747 |
| 342 | 1748 // call below, since it affects the metric by which we sort the heap |
| 1749 // regions. | |
| 1750 if (G1ScrubRemSets) { | |
| 1751 double rs_scrub_start = os::elapsedTime(); | |
| 1752 G1ParScrubRemSetTask g1_par_scrub_rs_task(g1h, &_region_bm, &_card_bm); | |
| 1753 if (ParallelGCThreads > 0) { | |
| 1754 int n_workers = g1h->workers()->total_workers(); | |
| 1755 g1h->set_par_threads(n_workers); | |
| 1756 g1h->workers()->run_task(&g1_par_scrub_rs_task); | |
| 1757 g1h->set_par_threads(0); | |
| 355 | 1758 |
| 1759 assert(g1h->check_heap_region_claim_values( | |
| 1760 HeapRegion::ScrubRemSetClaimValue), | |
| 1761 "sanity check"); | |
| 342 | 1762 } else { |
| 1763 g1_par_scrub_rs_task.work(0); | |
| 1764 } | |
| 1765 | |
| 1766 double rs_scrub_end = os::elapsedTime(); | |
| 1767 double this_rs_scrub_time = (rs_scrub_end - rs_scrub_start); | |
| 1768 _total_rs_scrub_time += this_rs_scrub_time; | |
| 1769 } | |
| 1770 | |
| 1771 // this will also free any regions totally full of garbage objects, | |
| 1772 // and sort the regions. | |
| 1773 g1h->g1_policy()->record_concurrent_mark_cleanup_end( | |
| 1774 g1_par_note_end_task.freed_bytes(), | |
| 1775 g1_par_note_end_task.max_live_bytes()); | |
| 1776 | |
| 1777 // Statistics. | |
| 1778 double end = os::elapsedTime(); | |
| 1779 _cleanup_times.add((end - start) * 1000.0); | |
| 1780 GCOverheadReporter::recordSTWEnd(end); | |
| 1781 | |
| 1782 // G1CollectedHeap::heap()->print(); | |
| 1783 // gclog_or_tty->print_cr("HEAP GC TIME STAMP : %d", | |
| 1784 // G1CollectedHeap::heap()->get_gc_time_stamp()); | |
| 1785 | |
| 1786 if (PrintGC || PrintGCDetails) { | |
| 1787 g1h->print_size_transition(gclog_or_tty, | |
| 1788 start_used_bytes, | |
| 1789 g1h->used(), | |
| 1790 g1h->capacity()); | |
| 1791 } | |
| 1792 | |
| 1793 size_t cleaned_up_bytes = start_used_bytes - g1h->used(); | |
| 1794 g1p->decrease_known_garbage_bytes(cleaned_up_bytes); | |
| 1795 | |
| 1796 // We need to make this be a "collection" so any collection pause that | |
| 1797 // races with it goes around and waits for completeCleanup to finish. | |
| 1798 g1h->increment_total_collections(); | |
| 1799 | |
| 751 | 1800 if (VerifyDuringGC) { |
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1801 HandleMark hm; // handle scope |
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1802 gclog_or_tty->print(" VerifyDuringGC:(after)"); |
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1803 Universe::heap()->prepare_for_verify(); |
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1804 Universe::verify(/* allow dirty */ true, |
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1805 /* silent */ false, |
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1806 /* prev marking */ true); |
| 342 | 1807 } |
| 1808 } | |
| 1809 | |
| 1810 void ConcurrentMark::completeCleanup() { | |
| 1811 // A full collection intervened. | |
| 1812 if (has_aborted()) return; | |
| 1813 | |
| 1814 int first = 0; | |
| 1815 int last = (int)MAX2(ParallelGCThreads, (size_t)1); | |
| 1816 for (int t = 0; t < last; t++) { | |
| 1817 UncleanRegionList* list = &_par_cleanup_thread_state[t]->list; | |
| 1818 assert(list->well_formed(), "Inv"); | |
| 1819 HeapRegion* hd = list->hd(); | |
| 1820 while (hd != NULL) { | |
| 1821 // Now finish up the other stuff. | |
| 1822 hd->rem_set()->clear(); | |
| 1823 HeapRegion* next_hd = hd->next_from_unclean_list(); | |
| 1824 (void)list->pop(); | |
| 1825 guarantee(list->hd() == next_hd, "how not?"); | |
| 1826 _g1h->put_region_on_unclean_list(hd); | |
| 1827 if (!hd->isHumongous()) { | |
| 1828 // Add this to the _free_regions count by 1. | |
| 1829 _g1h->finish_free_region_work(0, 0, 1, NULL); | |
| 1830 } | |
| 1831 hd = list->hd(); | |
| 1832 guarantee(hd == next_hd, "how not?"); | |
| 1833 } | |
| 1834 } | |
| 1835 } | |
| 1836 | |
| 1837 | |
| 1838 class G1CMIsAliveClosure: public BoolObjectClosure { | |
| 1839 G1CollectedHeap* _g1; | |
| 1840 public: | |
| 1841 G1CMIsAliveClosure(G1CollectedHeap* g1) : | |
| 1842 _g1(g1) | |
| 1843 {} | |
| 1844 | |
| 1845 void do_object(oop obj) { | |
| 1846 assert(false, "not to be invoked"); | |
| 1847 } | |
| 1848 bool do_object_b(oop obj) { | |
| 1849 HeapWord* addr = (HeapWord*)obj; | |
| 1850 return addr != NULL && | |
| 1851 (!_g1->is_in_g1_reserved(addr) || !_g1->is_obj_ill(obj)); | |
| 1852 } | |
| 1853 }; | |
| 1854 | |
| 1855 class G1CMKeepAliveClosure: public OopClosure { | |
| 1856 G1CollectedHeap* _g1; | |
| 1857 ConcurrentMark* _cm; | |
| 1858 CMBitMap* _bitMap; | |
| 1859 public: | |
| 1860 G1CMKeepAliveClosure(G1CollectedHeap* g1, ConcurrentMark* cm, | |
| 1861 CMBitMap* bitMap) : | |
| 1862 _g1(g1), _cm(cm), | |
| 1863 _bitMap(bitMap) {} | |
| 1864 | |
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1865 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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1866 virtual void do_oop( oop* p) { do_oop_work(p); } |
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1867 |
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1868 template <class T> void do_oop_work(T* p) { |
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1869 oop thisOop = oopDesc::load_decode_heap_oop(p); |
| 342 | 1870 HeapWord* addr = (HeapWord*)thisOop; |
| 1871 if (_g1->is_in_g1_reserved(addr) && _g1->is_obj_ill(thisOop)) { | |
| 1872 _bitMap->mark(addr); | |
| 1873 _cm->mark_stack_push(thisOop); | |
| 1874 } | |
| 1875 } | |
| 1876 }; | |
| 1877 | |
| 1878 class G1CMDrainMarkingStackClosure: public VoidClosure { | |
| 1879 CMMarkStack* _markStack; | |
| 1880 CMBitMap* _bitMap; | |
| 1881 G1CMKeepAliveClosure* _oopClosure; | |
| 1882 public: | |
| 1883 G1CMDrainMarkingStackClosure(CMBitMap* bitMap, CMMarkStack* markStack, | |
| 1884 G1CMKeepAliveClosure* oopClosure) : | |
| 1885 _bitMap(bitMap), | |
| 1886 _markStack(markStack), | |
| 1887 _oopClosure(oopClosure) | |
| 1888 {} | |
| 1889 | |
| 1890 void do_void() { | |
| 1891 _markStack->drain((OopClosure*)_oopClosure, _bitMap, false); | |
| 1892 } | |
| 1893 }; | |
| 1894 | |
| 1895 void ConcurrentMark::weakRefsWork(bool clear_all_soft_refs) { | |
| 1896 ResourceMark rm; | |
| 1897 HandleMark hm; | |
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1898 G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
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1899 ReferenceProcessor* rp = g1h->ref_processor(); |
| 342 | 1900 |
| 1901 // Process weak references. | |
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1902 rp->setup_policy(clear_all_soft_refs); |
| 342 | 1903 assert(_markStack.isEmpty(), "mark stack should be empty"); |
| 1904 | |
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1905 G1CMIsAliveClosure g1IsAliveClosure (g1h); |
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1906 G1CMKeepAliveClosure g1KeepAliveClosure(g1h, this, nextMarkBitMap()); |
| 342 | 1907 G1CMDrainMarkingStackClosure |
| 1908 g1DrainMarkingStackClosure(nextMarkBitMap(), &_markStack, | |
| 1909 &g1KeepAliveClosure); | |
| 1910 | |
| 1911 // XXXYYY Also: copy the parallel ref processing code from CMS. | |
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1912 rp->process_discovered_references(&g1IsAliveClosure, |
| 342 | 1913 &g1KeepAliveClosure, |
| 1914 &g1DrainMarkingStackClosure, | |
| 1915 NULL); | |
| 1916 assert(_markStack.overflow() || _markStack.isEmpty(), | |
| 1917 "mark stack should be empty (unless it overflowed)"); | |
| 1918 if (_markStack.overflow()) { | |
| 1919 set_has_overflown(); | |
| 1920 } | |
| 1921 | |
| 1922 rp->enqueue_discovered_references(); | |
| 1923 rp->verify_no_references_recorded(); | |
| 1924 assert(!rp->discovery_enabled(), "should have been disabled"); | |
| 1925 | |
| 1926 // Now clean up stale oops in SymbolTable and StringTable | |
| 1927 SymbolTable::unlink(&g1IsAliveClosure); | |
| 1928 StringTable::unlink(&g1IsAliveClosure); | |
| 1929 } | |
| 1930 | |
| 1931 void ConcurrentMark::swapMarkBitMaps() { | |
| 1932 CMBitMapRO* temp = _prevMarkBitMap; | |
| 1933 _prevMarkBitMap = (CMBitMapRO*)_nextMarkBitMap; | |
| 1934 _nextMarkBitMap = (CMBitMap*) temp; | |
| 1935 } | |
| 1936 | |
| 1937 class CMRemarkTask: public AbstractGangTask { | |
| 1938 private: | |
| 1939 ConcurrentMark *_cm; | |
| 1940 | |
| 1941 public: | |
| 1942 void work(int worker_i) { | |
| 1943 // Since all available tasks are actually started, we should | |
| 1944 // only proceed if we're supposed to be actived. | |
| 1945 if ((size_t)worker_i < _cm->active_tasks()) { | |
| 1946 CMTask* task = _cm->task(worker_i); | |
| 1947 task->record_start_time(); | |
| 1948 do { | |
| 1949 task->do_marking_step(1000000000.0 /* something very large */); | |
| 1950 } while (task->has_aborted() && !_cm->has_overflown()); | |
| 1951 // If we overflow, then we do not want to restart. We instead | |
| 1952 // want to abort remark and do concurrent marking again. | |
| 1953 task->record_end_time(); | |
| 1954 } | |
| 1955 } | |
| 1956 | |
| 1957 CMRemarkTask(ConcurrentMark* cm) : | |
| 1958 AbstractGangTask("Par Remark"), _cm(cm) { } | |
| 1959 }; | |
| 1960 | |
| 1961 void ConcurrentMark::checkpointRootsFinalWork() { | |
| 1962 ResourceMark rm; | |
| 1963 HandleMark hm; | |
| 1964 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1965 | |
| 1966 g1h->ensure_parsability(false); | |
| 1967 | |
| 1968 if (ParallelGCThreads > 0) { | |
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1969 G1CollectedHeap::StrongRootsScope srs(g1h); |
| 342 | 1970 // this is remark, so we'll use up all available threads |
| 1971 int active_workers = ParallelGCThreads; | |
| 1972 set_phase(active_workers, false); | |
| 1973 | |
| 1974 CMRemarkTask remarkTask(this); | |
| 1975 // We will start all available threads, even if we decide that the | |
| 1976 // active_workers will be fewer. The extra ones will just bail out | |
| 1977 // immediately. | |
| 1978 int n_workers = g1h->workers()->total_workers(); | |
| 1979 g1h->set_par_threads(n_workers); | |
| 1980 g1h->workers()->run_task(&remarkTask); | |
| 1981 g1h->set_par_threads(0); | |
| 1982 | |
| 1983 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 1984 guarantee( satb_mq_set.completed_buffers_num() == 0, "invariant" ); | |
| 1985 } else { | |
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1986 G1CollectedHeap::StrongRootsScope srs(g1h); |
| 342 | 1987 // this is remark, so we'll use up all available threads |
| 1988 int active_workers = 1; | |
| 1989 set_phase(active_workers, false); | |
| 1990 | |
| 1991 CMRemarkTask remarkTask(this); | |
| 1992 // We will start all available threads, even if we decide that the | |
| 1993 // active_workers will be fewer. The extra ones will just bail out | |
| 1994 // immediately. | |
| 1995 remarkTask.work(0); | |
| 1996 | |
| 1997 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 1998 guarantee( satb_mq_set.completed_buffers_num() == 0, "invariant" ); | |
| 1999 } | |
| 2000 | |
| 2001 print_stats(); | |
| 2002 | |
| 2003 if (!restart_for_overflow()) | |
| 2004 set_non_marking_state(); | |
| 2005 | |
| 2006 #if VERIFY_OBJS_PROCESSED | |
| 2007 if (_scan_obj_cl.objs_processed != ThreadLocalObjQueue::objs_enqueued) { | |
| 2008 gclog_or_tty->print_cr("Processed = %d, enqueued = %d.", | |
| 2009 _scan_obj_cl.objs_processed, | |
| 2010 ThreadLocalObjQueue::objs_enqueued); | |
| 2011 guarantee(_scan_obj_cl.objs_processed == | |
| 2012 ThreadLocalObjQueue::objs_enqueued, | |
| 2013 "Different number of objs processed and enqueued."); | |
| 2014 } | |
| 2015 #endif | |
| 2016 } | |
| 2017 | |
| 2018 class ReachablePrinterOopClosure: public OopClosure { | |
| 2019 private: | |
| 2020 G1CollectedHeap* _g1h; | |
| 2021 CMBitMapRO* _bitmap; | |
| 2022 outputStream* _out; | |
| 2023 | |
| 2024 public: | |
| 2025 ReachablePrinterOopClosure(CMBitMapRO* bitmap, outputStream* out) : | |
| 2026 _bitmap(bitmap), _g1h(G1CollectedHeap::heap()), _out(out) { } | |
| 2027 | |
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2028 void do_oop(narrowOop* p) { do_oop_work(p); } |
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2029 void do_oop( oop* p) { do_oop_work(p); } |
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2030 |
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2031 template <class T> void do_oop_work(T* p) { |
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2032 oop obj = oopDesc::load_decode_heap_oop(p); |
| 342 | 2033 const char* str = NULL; |
| 2034 const char* str2 = ""; | |
| 2035 | |
| 2036 if (!_g1h->is_in_g1_reserved(obj)) | |
| 2037 str = "outside G1 reserved"; | |
| 2038 else { | |
| 2039 HeapRegion* hr = _g1h->heap_region_containing(obj); | |
| 2040 guarantee( hr != NULL, "invariant" ); | |
| 2041 if (hr->obj_allocated_since_prev_marking(obj)) { | |
| 2042 str = "over TAMS"; | |
| 2043 if (_bitmap->isMarked((HeapWord*) obj)) | |
| 2044 str2 = " AND MARKED"; | |
| 2045 } else if (_bitmap->isMarked((HeapWord*) obj)) | |
| 2046 str = "marked"; | |
| 2047 else | |
| 2048 str = "#### NOT MARKED ####"; | |
| 2049 } | |
| 2050 | |
| 2051 _out->print_cr(" "PTR_FORMAT" contains "PTR_FORMAT" %s%s", | |
| 2052 p, (void*) obj, str, str2); | |
| 2053 } | |
| 2054 }; | |
| 2055 | |
| 2056 class ReachablePrinterClosure: public BitMapClosure { | |
| 2057 private: | |
| 2058 CMBitMapRO* _bitmap; | |
| 2059 outputStream* _out; | |
| 2060 | |
| 2061 public: | |
| 2062 ReachablePrinterClosure(CMBitMapRO* bitmap, outputStream* out) : | |
| 2063 _bitmap(bitmap), _out(out) { } | |
| 2064 | |
| 2065 bool do_bit(size_t offset) { | |
| 2066 HeapWord* addr = _bitmap->offsetToHeapWord(offset); | |
| 2067 ReachablePrinterOopClosure oopCl(_bitmap, _out); | |
| 2068 | |
| 2069 _out->print_cr(" obj "PTR_FORMAT", offset %10d (marked)", addr, offset); | |
| 2070 oop(addr)->oop_iterate(&oopCl); | |
| 2071 _out->print_cr(""); | |
| 2072 | |
| 2073 return true; | |
| 2074 } | |
| 2075 }; | |
| 2076 | |
| 2077 class ObjInRegionReachablePrinterClosure : public ObjectClosure { | |
| 2078 private: | |
| 2079 CMBitMapRO* _bitmap; | |
| 2080 outputStream* _out; | |
| 2081 | |
| 2082 public: | |
| 2083 void do_object(oop o) { | |
| 2084 ReachablePrinterOopClosure oopCl(_bitmap, _out); | |
| 2085 | |
| 2086 _out->print_cr(" obj "PTR_FORMAT" (over TAMS)", (void*) o); | |
| 2087 o->oop_iterate(&oopCl); | |
| 2088 _out->print_cr(""); | |
| 2089 } | |
| 2090 | |
| 2091 ObjInRegionReachablePrinterClosure(CMBitMapRO* bitmap, outputStream* out) : | |
| 2092 _bitmap(bitmap), _out(out) { } | |
| 2093 }; | |
| 2094 | |
| 2095 class RegionReachablePrinterClosure : public HeapRegionClosure { | |
| 2096 private: | |
| 2097 CMBitMapRO* _bitmap; | |
| 2098 outputStream* _out; | |
| 2099 | |
| 2100 public: | |
| 2101 bool doHeapRegion(HeapRegion* hr) { | |
| 2102 HeapWord* b = hr->bottom(); | |
| 2103 HeapWord* e = hr->end(); | |
| 2104 HeapWord* t = hr->top(); | |
| 2105 HeapWord* p = hr->prev_top_at_mark_start(); | |
| 2106 _out->print_cr("** ["PTR_FORMAT", "PTR_FORMAT"] top: "PTR_FORMAT" " | |
| 2107 "PTAMS: "PTR_FORMAT, b, e, t, p); | |
| 2108 _out->print_cr(""); | |
| 2109 | |
| 2110 ObjInRegionReachablePrinterClosure ocl(_bitmap, _out); | |
| 2111 hr->object_iterate_mem_careful(MemRegion(p, t), &ocl); | |
| 2112 | |
| 2113 return false; | |
| 2114 } | |
| 2115 | |
| 2116 RegionReachablePrinterClosure(CMBitMapRO* bitmap, | |
| 2117 outputStream* out) : | |
| 2118 _bitmap(bitmap), _out(out) { } | |
| 2119 }; | |
| 2120 | |
| 2121 void ConcurrentMark::print_prev_bitmap_reachable() { | |
| 2122 outputStream* out = gclog_or_tty; | |
| 2123 | |
| 2124 #if SEND_HEAP_DUMP_TO_FILE | |
| 2125 guarantee(heap_dump_file == NULL, "Protocol"); | |
| 2126 char fn_buf[100]; | |
| 2127 sprintf(fn_buf, "/tmp/dump.txt.%d", os::current_process_id()); | |
| 2128 heap_dump_file = fopen(fn_buf, "w"); | |
| 2129 fileStream fstream(heap_dump_file); | |
| 2130 out = &fstream; | |
| 2131 #endif // SEND_HEAP_DUMP_TO_FILE | |
| 2132 | |
| 2133 RegionReachablePrinterClosure rcl(_prevMarkBitMap, out); | |
| 2134 out->print_cr("--- ITERATING OVER REGIONS WITH PTAMS < TOP"); | |
| 2135 _g1h->heap_region_iterate(&rcl); | |
| 2136 out->print_cr(""); | |
| 2137 | |
| 2138 ReachablePrinterClosure cl(_prevMarkBitMap, out); | |
| 2139 out->print_cr("--- REACHABLE OBJECTS ON THE BITMAP"); | |
| 2140 _prevMarkBitMap->iterate(&cl); | |
| 2141 out->print_cr(""); | |
| 2142 | |
| 2143 #if SEND_HEAP_DUMP_TO_FILE | |
| 2144 fclose(heap_dump_file); | |
| 2145 heap_dump_file = NULL; | |
| 2146 #endif // SEND_HEAP_DUMP_TO_FILE | |
| 2147 } | |
| 2148 | |
| 2149 // This note is for drainAllSATBBuffers and the code in between. | |
| 2150 // In the future we could reuse a task to do this work during an | |
| 2151 // evacuation pause (since now tasks are not active and can be claimed | |
| 2152 // during an evacuation pause). This was a late change to the code and | |
| 2153 // is currently not being taken advantage of. | |
| 2154 | |
| 2155 class CMGlobalObjectClosure : public ObjectClosure { | |
| 2156 private: | |
| 2157 ConcurrentMark* _cm; | |
| 2158 | |
| 2159 public: | |
| 2160 void do_object(oop obj) { | |
| 2161 _cm->deal_with_reference(obj); | |
| 2162 } | |
| 2163 | |
| 2164 CMGlobalObjectClosure(ConcurrentMark* cm) : _cm(cm) { } | |
| 2165 }; | |
| 2166 | |
| 2167 void ConcurrentMark::deal_with_reference(oop obj) { | |
| 2168 if (verbose_high()) | |
| 2169 gclog_or_tty->print_cr("[global] we're dealing with reference "PTR_FORMAT, | |
| 2170 (void*) obj); | |
| 2171 | |
| 2172 | |
| 2173 HeapWord* objAddr = (HeapWord*) obj; | |
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2174 assert(obj->is_oop_or_null(true /* ignore mark word */), "Error"); |
| 342 | 2175 if (_g1h->is_in_g1_reserved(objAddr)) { |
| 2176 tmp_guarantee_CM( obj != NULL, "is_in_g1_reserved should ensure this" ); | |
| 2177 HeapRegion* hr = _g1h->heap_region_containing(obj); | |
| 2178 if (_g1h->is_obj_ill(obj, hr)) { | |
| 2179 if (verbose_high()) | |
| 2180 gclog_or_tty->print_cr("[global] "PTR_FORMAT" is not considered " | |
| 2181 "marked", (void*) obj); | |
| 2182 | |
| 2183 // we need to mark it first | |
| 2184 if (_nextMarkBitMap->parMark(objAddr)) { | |
| 2185 // No OrderAccess:store_load() is needed. It is implicit in the | |
| 2186 // CAS done in parMark(objAddr) above | |
| 2187 HeapWord* finger = _finger; | |
| 2188 if (objAddr < finger) { | |
| 2189 if (verbose_high()) | |
| 2190 gclog_or_tty->print_cr("[global] below the global finger " | |
| 2191 "("PTR_FORMAT"), pushing it", finger); | |
| 2192 if (!mark_stack_push(obj)) { | |
| 2193 if (verbose_low()) | |
| 2194 gclog_or_tty->print_cr("[global] global stack overflow during " | |
| 2195 "deal_with_reference"); | |
| 2196 } | |
| 2197 } | |
| 2198 } | |
| 2199 } | |
| 2200 } | |
| 2201 } | |
| 2202 | |
| 2203 void ConcurrentMark::drainAllSATBBuffers() { | |
| 2204 CMGlobalObjectClosure oc(this); | |
| 2205 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 2206 satb_mq_set.set_closure(&oc); | |
| 2207 | |
| 2208 while (satb_mq_set.apply_closure_to_completed_buffer()) { | |
| 2209 if (verbose_medium()) | |
| 2210 gclog_or_tty->print_cr("[global] processed an SATB buffer"); | |
| 2211 } | |
| 2212 | |
| 2213 // no need to check whether we should do this, as this is only | |
| 2214 // called during an evacuation pause | |
| 2215 satb_mq_set.iterate_closure_all_threads(); | |
| 2216 | |
| 2217 satb_mq_set.set_closure(NULL); | |
| 2218 guarantee( satb_mq_set.completed_buffers_num() == 0, "invariant" ); | |
| 2219 } | |
| 2220 | |
| 2221 void ConcurrentMark::markPrev(oop p) { | |
| 2222 // Note we are overriding the read-only view of the prev map here, via | |
| 2223 // the cast. | |
| 2224 ((CMBitMap*)_prevMarkBitMap)->mark((HeapWord*)p); | |
| 2225 } | |
| 2226 | |
| 2227 void ConcurrentMark::clear(oop p) { | |
| 2228 assert(p != NULL && p->is_oop(), "expected an oop"); | |
| 2229 HeapWord* addr = (HeapWord*)p; | |
| 2230 assert(addr >= _nextMarkBitMap->startWord() || | |
| 2231 addr < _nextMarkBitMap->endWord(), "in a region"); | |
| 2232 | |
| 2233 _nextMarkBitMap->clear(addr); | |
| 2234 } | |
| 2235 | |
| 2236 void ConcurrentMark::clearRangeBothMaps(MemRegion mr) { | |
| 2237 // Note we are overriding the read-only view of the prev map here, via | |
| 2238 // the cast. | |
| 2239 ((CMBitMap*)_prevMarkBitMap)->clearRange(mr); | |
| 2240 _nextMarkBitMap->clearRange(mr); | |
| 2241 } | |
| 2242 | |
| 2243 HeapRegion* | |
| 2244 ConcurrentMark::claim_region(int task_num) { | |
| 2245 // "checkpoint" the finger | |
| 2246 HeapWord* finger = _finger; | |
| 2247 | |
| 2248 // _heap_end will not change underneath our feet; it only changes at | |
| 2249 // yield points. | |
| 2250 while (finger < _heap_end) { | |
| 2251 tmp_guarantee_CM( _g1h->is_in_g1_reserved(finger), "invariant" ); | |
| 2252 | |
| 2253 // is the gap between reading the finger and doing the CAS too long? | |
| 2254 | |
| 2255 HeapRegion* curr_region = _g1h->heap_region_containing(finger); | |
| 2256 HeapWord* bottom = curr_region->bottom(); | |
| 2257 HeapWord* end = curr_region->end(); | |
| 2258 HeapWord* limit = curr_region->next_top_at_mark_start(); | |
| 2259 | |
| 2260 if (verbose_low()) | |
| 2261 gclog_or_tty->print_cr("[%d] curr_region = "PTR_FORMAT" " | |
| 2262 "["PTR_FORMAT", "PTR_FORMAT"), " | |
| 2263 "limit = "PTR_FORMAT, | |
| 2264 task_num, curr_region, bottom, end, limit); | |
| 2265 | |
| 2266 HeapWord* res = | |
| 2267 (HeapWord*) Atomic::cmpxchg_ptr(end, &_finger, finger); | |
| 2268 if (res == finger) { | |
| 2269 // we succeeded | |
| 2270 | |
| 2271 // notice that _finger == end cannot be guaranteed here since, | |
| 2272 // someone else might have moved the finger even further | |
| 2273 guarantee( _finger >= end, "the finger should have moved forward" ); | |
| 2274 | |
| 2275 if (verbose_low()) | |
| 2276 gclog_or_tty->print_cr("[%d] we were successful with region = " | |
| 2277 PTR_FORMAT, task_num, curr_region); | |
| 2278 | |
| 2279 if (limit > bottom) { | |
| 2280 if (verbose_low()) | |
| 2281 gclog_or_tty->print_cr("[%d] region "PTR_FORMAT" is not empty, " | |
| 2282 "returning it ", task_num, curr_region); | |
| 2283 return curr_region; | |
| 2284 } else { | |
| 2285 tmp_guarantee_CM( limit == bottom, | |
| 2286 "the region limit should be at bottom" ); | |
| 2287 if (verbose_low()) | |
| 2288 gclog_or_tty->print_cr("[%d] region "PTR_FORMAT" is empty, " | |
| 2289 "returning NULL", task_num, curr_region); | |
| 2290 // we return NULL and the caller should try calling | |
| 2291 // claim_region() again. | |
| 2292 return NULL; | |
| 2293 } | |
| 2294 } else { | |
| 2295 guarantee( _finger > finger, "the finger should have moved forward" ); | |
| 2296 if (verbose_low()) | |
| 2297 gclog_or_tty->print_cr("[%d] somebody else moved the finger, " | |
| 2298 "global finger = "PTR_FORMAT", " | |
| 2299 "our finger = "PTR_FORMAT, | |
| 2300 task_num, _finger, finger); | |
| 2301 | |
| 2302 // read it again | |
| 2303 finger = _finger; | |
| 2304 } | |
| 2305 } | |
| 2306 | |
| 2307 return NULL; | |
| 2308 } | |
| 2309 | |
| 2310 void ConcurrentMark::oops_do(OopClosure* cl) { | |
| 2311 if (_markStack.size() > 0 && verbose_low()) | |
| 2312 gclog_or_tty->print_cr("[global] scanning the global marking stack, " | |
| 2313 "size = %d", _markStack.size()); | |
| 2314 // we first iterate over the contents of the mark stack... | |
| 2315 _markStack.oops_do(cl); | |
| 2316 | |
| 2317 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 2318 OopTaskQueue* queue = _task_queues->queue((int)i); | |
| 2319 | |
| 2320 if (queue->size() > 0 && verbose_low()) | |
| 2321 gclog_or_tty->print_cr("[global] scanning task queue of task %d, " | |
| 2322 "size = %d", i, queue->size()); | |
| 2323 | |
| 2324 // ...then over the contents of the all the task queues. | |
| 2325 queue->oops_do(cl); | |
| 2326 } | |
| 2327 | |
| 2328 // finally, invalidate any entries that in the region stack that | |
| 2329 // point into the collection set | |
| 2330 if (_regionStack.invalidate_entries_into_cset()) { | |
| 2331 // otherwise, any gray objects copied during the evacuation pause | |
| 2332 // might not be visited. | |
| 2333 guarantee( _should_gray_objects, "invariant" ); | |
| 2334 } | |
| 2335 } | |
| 2336 | |
| 2337 void ConcurrentMark::clear_marking_state() { | |
| 2338 _markStack.setEmpty(); | |
| 2339 _markStack.clear_overflow(); | |
| 2340 _regionStack.setEmpty(); | |
| 2341 _regionStack.clear_overflow(); | |
| 2342 clear_has_overflown(); | |
| 2343 _finger = _heap_start; | |
| 2344 | |
| 2345 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 2346 OopTaskQueue* queue = _task_queues->queue(i); | |
| 2347 queue->set_empty(); | |
| 2348 } | |
| 2349 } | |
| 2350 | |
| 2351 void ConcurrentMark::print_stats() { | |
| 2352 if (verbose_stats()) { | |
| 2353 gclog_or_tty->print_cr("---------------------------------------------------------------------"); | |
| 2354 for (size_t i = 0; i < _active_tasks; ++i) { | |
| 2355 _tasks[i]->print_stats(); | |
| 2356 gclog_or_tty->print_cr("---------------------------------------------------------------------"); | |
| 2357 } | |
| 2358 } | |
| 2359 } | |
| 2360 | |
| 2361 class CSMarkOopClosure: public OopClosure { | |
| 2362 friend class CSMarkBitMapClosure; | |
| 2363 | |
| 2364 G1CollectedHeap* _g1h; | |
| 2365 CMBitMap* _bm; | |
| 2366 ConcurrentMark* _cm; | |
| 2367 oop* _ms; | |
| 2368 jint* _array_ind_stack; | |
| 2369 int _ms_size; | |
| 2370 int _ms_ind; | |
| 2371 int _array_increment; | |
| 2372 | |
| 2373 bool push(oop obj, int arr_ind = 0) { | |
| 2374 if (_ms_ind == _ms_size) { | |
| 2375 gclog_or_tty->print_cr("Mark stack is full."); | |
| 2376 return false; | |
| 2377 } | |
| 2378 _ms[_ms_ind] = obj; | |
| 2379 if (obj->is_objArray()) _array_ind_stack[_ms_ind] = arr_ind; | |
| 2380 _ms_ind++; | |
| 2381 return true; | |
| 2382 } | |
| 2383 | |
| 2384 oop pop() { | |
| 2385 if (_ms_ind == 0) return NULL; | |
| 2386 else { | |
| 2387 _ms_ind--; | |
| 2388 return _ms[_ms_ind]; | |
| 2389 } | |
| 2390 } | |
| 2391 | |
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2392 template <class T> bool drain() { |
| 342 | 2393 while (_ms_ind > 0) { |
| 2394 oop obj = pop(); | |
| 2395 assert(obj != NULL, "Since index was non-zero."); | |
| 2396 if (obj->is_objArray()) { | |
| 2397 jint arr_ind = _array_ind_stack[_ms_ind]; | |
| 2398 objArrayOop aobj = objArrayOop(obj); | |
| 2399 jint len = aobj->length(); | |
| 2400 jint next_arr_ind = arr_ind + _array_increment; | |
| 2401 if (next_arr_ind < len) { | |
| 2402 push(obj, next_arr_ind); | |
| 2403 } | |
| 2404 // Now process this portion of this one. | |
| 2405 int lim = MIN2(next_arr_ind, len); | |
| 2406 for (int j = arr_ind; j < lim; j++) { | |
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2407 do_oop(aobj->objArrayOopDesc::obj_at_addr<T>(j)); |
| 342 | 2408 } |
| 2409 | |
| 2410 } else { | |
| 2411 obj->oop_iterate(this); | |
| 2412 } | |
| 2413 if (abort()) return false; | |
| 2414 } | |
| 2415 return true; | |
| 2416 } | |
| 2417 | |
| 2418 public: | |
| 2419 CSMarkOopClosure(ConcurrentMark* cm, int ms_size) : | |
| 2420 _g1h(G1CollectedHeap::heap()), | |
| 2421 _cm(cm), | |
| 2422 _bm(cm->nextMarkBitMap()), | |
| 2423 _ms_size(ms_size), _ms_ind(0), | |
| 2424 _ms(NEW_C_HEAP_ARRAY(oop, ms_size)), | |
| 2425 _array_ind_stack(NEW_C_HEAP_ARRAY(jint, ms_size)), | |
| 2426 _array_increment(MAX2(ms_size/8, 16)) | |
| 2427 {} | |
| 2428 | |
| 2429 ~CSMarkOopClosure() { | |
| 2430 FREE_C_HEAP_ARRAY(oop, _ms); | |
| 2431 FREE_C_HEAP_ARRAY(jint, _array_ind_stack); | |
| 2432 } | |
| 2433 | |
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2434 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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2435 virtual void do_oop( oop* p) { do_oop_work(p); } |
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2436 |
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2437 template <class T> void do_oop_work(T* p) { |
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2438 T heap_oop = oopDesc::load_heap_oop(p); |
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2439 if (oopDesc::is_null(heap_oop)) return; |
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2440 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); |
| 342 | 2441 if (obj->is_forwarded()) { |
| 2442 // If the object has already been forwarded, we have to make sure | |
| 2443 // that it's marked. So follow the forwarding pointer. Note that | |
| 2444 // this does the right thing for self-forwarding pointers in the | |
| 2445 // evacuation failure case. | |
| 2446 obj = obj->forwardee(); | |
| 2447 } | |
| 2448 HeapRegion* hr = _g1h->heap_region_containing(obj); | |
| 2449 if (hr != NULL) { | |
| 2450 if (hr->in_collection_set()) { | |
| 2451 if (_g1h->is_obj_ill(obj)) { | |
| 2452 _bm->mark((HeapWord*)obj); | |
| 2453 if (!push(obj)) { | |
| 2454 gclog_or_tty->print_cr("Setting abort in CSMarkOopClosure because push failed."); | |
| 2455 set_abort(); | |
| 2456 } | |
| 2457 } | |
| 2458 } else { | |
| 2459 // Outside the collection set; we need to gray it | |
| 2460 _cm->deal_with_reference(obj); | |
| 2461 } | |
| 2462 } | |
| 2463 } | |
| 2464 }; | |
| 2465 | |
| 2466 class CSMarkBitMapClosure: public BitMapClosure { | |
| 2467 G1CollectedHeap* _g1h; | |
| 2468 CMBitMap* _bitMap; | |
| 2469 ConcurrentMark* _cm; | |
| 2470 CSMarkOopClosure _oop_cl; | |
| 2471 public: | |
| 2472 CSMarkBitMapClosure(ConcurrentMark* cm, int ms_size) : | |
| 2473 _g1h(G1CollectedHeap::heap()), | |
| 2474 _bitMap(cm->nextMarkBitMap()), | |
| 2475 _oop_cl(cm, ms_size) | |
| 2476 {} | |
| 2477 | |
| 2478 ~CSMarkBitMapClosure() {} | |
| 2479 | |
| 2480 bool do_bit(size_t offset) { | |
| 2481 // convert offset into a HeapWord* | |
| 2482 HeapWord* addr = _bitMap->offsetToHeapWord(offset); | |
| 2483 assert(_bitMap->endWord() && addr < _bitMap->endWord(), | |
| 2484 "address out of range"); | |
| 2485 assert(_bitMap->isMarked(addr), "tautology"); | |
| 2486 oop obj = oop(addr); | |
| 2487 if (!obj->is_forwarded()) { | |
| 2488 if (!_oop_cl.push(obj)) return false; | |
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2489 if (UseCompressedOops) { |
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2490 if (!_oop_cl.drain<narrowOop>()) return false; |
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2491 } else { |
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2492 if (!_oop_cl.drain<oop>()) return false; |
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2493 } |
| 342 | 2494 } |
| 2495 // Otherwise... | |
| 2496 return true; | |
| 2497 } | |
| 2498 }; | |
| 2499 | |
| 2500 | |
| 2501 class CompleteMarkingInCSHRClosure: public HeapRegionClosure { | |
| 2502 CMBitMap* _bm; | |
| 2503 CSMarkBitMapClosure _bit_cl; | |
| 2504 enum SomePrivateConstants { | |
| 2505 MSSize = 1000 | |
| 2506 }; | |
| 2507 bool _completed; | |
| 2508 public: | |
| 2509 CompleteMarkingInCSHRClosure(ConcurrentMark* cm) : | |
| 2510 _bm(cm->nextMarkBitMap()), | |
| 2511 _bit_cl(cm, MSSize), | |
| 2512 _completed(true) | |
| 2513 {} | |
| 2514 | |
| 2515 ~CompleteMarkingInCSHRClosure() {} | |
| 2516 | |
| 2517 bool doHeapRegion(HeapRegion* r) { | |
| 2518 if (!r->evacuation_failed()) { | |
| 2519 MemRegion mr = MemRegion(r->bottom(), r->next_top_at_mark_start()); | |
| 2520 if (!mr.is_empty()) { | |
| 2521 if (!_bm->iterate(&_bit_cl, mr)) { | |
| 2522 _completed = false; | |
| 2523 return true; | |
| 2524 } | |
| 2525 } | |
| 2526 } | |
| 2527 return false; | |
| 2528 } | |
| 2529 | |
| 2530 bool completed() { return _completed; } | |
| 2531 }; | |
| 2532 | |
| 2533 class ClearMarksInHRClosure: public HeapRegionClosure { | |
| 2534 CMBitMap* _bm; | |
| 2535 public: | |
| 2536 ClearMarksInHRClosure(CMBitMap* bm): _bm(bm) { } | |
| 2537 | |
| 2538 bool doHeapRegion(HeapRegion* r) { | |
| 2539 if (!r->used_region().is_empty() && !r->evacuation_failed()) { | |
| 2540 MemRegion usedMR = r->used_region(); | |
| 2541 _bm->clearRange(r->used_region()); | |
| 2542 } | |
| 2543 return false; | |
| 2544 } | |
| 2545 }; | |
| 2546 | |
| 2547 void ConcurrentMark::complete_marking_in_collection_set() { | |
| 2548 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 2549 | |
| 2550 if (!g1h->mark_in_progress()) { | |
| 2551 g1h->g1_policy()->record_mark_closure_time(0.0); | |
| 2552 return; | |
| 2553 } | |
| 2554 | |
| 2555 int i = 1; | |
| 2556 double start = os::elapsedTime(); | |
| 2557 while (true) { | |
| 2558 i++; | |
| 2559 CompleteMarkingInCSHRClosure cmplt(this); | |
| 2560 g1h->collection_set_iterate(&cmplt); | |
| 2561 if (cmplt.completed()) break; | |
| 2562 } | |
| 2563 double end_time = os::elapsedTime(); | |
| 2564 double elapsed_time_ms = (end_time - start) * 1000.0; | |
| 2565 g1h->g1_policy()->record_mark_closure_time(elapsed_time_ms); | |
| 2566 if (PrintGCDetails) { | |
| 2567 gclog_or_tty->print_cr("Mark closure took %5.2f ms.", elapsed_time_ms); | |
| 2568 } | |
| 2569 | |
| 2570 ClearMarksInHRClosure clr(nextMarkBitMap()); | |
| 2571 g1h->collection_set_iterate(&clr); | |
| 2572 } | |
| 2573 | |
| 2574 // The next two methods deal with the following optimisation. Some | |
| 2575 // objects are gray by being marked and located above the finger. If | |
| 2576 // they are copied, during an evacuation pause, below the finger then | |
| 2577 // the need to be pushed on the stack. The observation is that, if | |
| 2578 // there are no regions in the collection set located above the | |
| 2579 // finger, then the above cannot happen, hence we do not need to | |
| 2580 // explicitly gray any objects when copying them to below the | |
| 2581 // finger. The global stack will be scanned to ensure that, if it | |
| 2582 // points to objects being copied, it will update their | |
| 2583 // location. There is a tricky situation with the gray objects in | |
| 2584 // region stack that are being coped, however. See the comment in | |
| 2585 // newCSet(). | |
| 2586 | |
| 2587 void ConcurrentMark::newCSet() { | |
| 2588 if (!concurrent_marking_in_progress()) | |
| 2589 // nothing to do if marking is not in progress | |
| 2590 return; | |
| 2591 | |
| 2592 // find what the lowest finger is among the global and local fingers | |
| 2593 _min_finger = _finger; | |
| 2594 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 2595 CMTask* task = _tasks[i]; | |
| 2596 HeapWord* task_finger = task->finger(); | |
| 2597 if (task_finger != NULL && task_finger < _min_finger) | |
| 2598 _min_finger = task_finger; | |
| 2599 } | |
| 2600 | |
| 2601 _should_gray_objects = false; | |
| 2602 | |
| 2603 // This fixes a very subtle and fustrating bug. It might be the case | |
| 2604 // that, during en evacuation pause, heap regions that contain | |
| 2605 // objects that are gray (by being in regions contained in the | |
| 2606 // region stack) are included in the collection set. Since such gray | |
| 2607 // objects will be moved, and because it's not easy to redirect | |
| 2608 // region stack entries to point to a new location (because objects | |
| 2609 // in one region might be scattered to multiple regions after they | |
| 2610 // are copied), one option is to ensure that all marked objects | |
| 2611 // copied during a pause are pushed on the stack. Notice, however, | |
| 2612 // that this problem can only happen when the region stack is not | |
| 2613 // empty during an evacuation pause. So, we make the fix a bit less | |
| 2614 // conservative and ensure that regions are pushed on the stack, | |
| 2615 // irrespective whether all collection set regions are below the | |
| 2616 // finger, if the region stack is not empty. This is expected to be | |
| 2617 // a rare case, so I don't think it's necessary to be smarted about it. | |
| 2618 if (!region_stack_empty()) | |
| 2619 _should_gray_objects = true; | |
| 2620 } | |
| 2621 | |
| 2622 void ConcurrentMark::registerCSetRegion(HeapRegion* hr) { | |
| 2623 if (!concurrent_marking_in_progress()) | |
| 2624 return; | |
| 2625 | |
| 2626 HeapWord* region_end = hr->end(); | |
| 2627 if (region_end > _min_finger) | |
| 2628 _should_gray_objects = true; | |
| 2629 } | |
| 2630 | |
| 2631 void ConcurrentMark::disable_co_trackers() { | |
| 2632 if (has_aborted()) { | |
| 2633 if (_cleanup_co_tracker.enabled()) | |
| 2634 _cleanup_co_tracker.disable(); | |
| 2635 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 2636 CMTask* task = _tasks[i]; | |
| 2637 if (task->co_tracker_enabled()) | |
| 2638 task->disable_co_tracker(); | |
| 2639 } | |
| 2640 } else { | |
| 2641 guarantee( !_cleanup_co_tracker.enabled(), "invariant" ); | |
| 2642 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 2643 CMTask* task = _tasks[i]; | |
| 2644 guarantee( !task->co_tracker_enabled(), "invariant" ); | |
| 2645 } | |
| 2646 } | |
| 2647 } | |
| 2648 | |
| 2649 // abandon current marking iteration due to a Full GC | |
| 2650 void ConcurrentMark::abort() { | |
| 2651 // Clear all marks to force marking thread to do nothing | |
| 2652 _nextMarkBitMap->clearAll(); | |
| 2653 // Empty mark stack | |
| 2654 clear_marking_state(); | |
| 2655 for (int i = 0; i < (int)_max_task_num; ++i) | |
| 2656 _tasks[i]->clear_region_fields(); | |
| 2657 _has_aborted = true; | |
| 2658 | |
| 2659 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 2660 satb_mq_set.abandon_partial_marking(); | |
| 2661 satb_mq_set.set_active_all_threads(false); | |
| 2662 } | |
| 2663 | |
| 2664 static void print_ms_time_info(const char* prefix, const char* name, | |
| 2665 NumberSeq& ns) { | |
| 2666 gclog_or_tty->print_cr("%s%5d %12s: total time = %8.2f s (avg = %8.2f ms).", | |
| 2667 prefix, ns.num(), name, ns.sum()/1000.0, ns.avg()); | |
| 2668 if (ns.num() > 0) { | |
| 2669 gclog_or_tty->print_cr("%s [std. dev = %8.2f ms, max = %8.2f ms]", | |
| 2670 prefix, ns.sd(), ns.maximum()); | |
| 2671 } | |
| 2672 } | |
| 2673 | |
| 2674 void ConcurrentMark::print_summary_info() { | |
| 2675 gclog_or_tty->print_cr(" Concurrent marking:"); | |
| 2676 print_ms_time_info(" ", "init marks", _init_times); | |
| 2677 print_ms_time_info(" ", "remarks", _remark_times); | |
| 2678 { | |
| 2679 print_ms_time_info(" ", "final marks", _remark_mark_times); | |
| 2680 print_ms_time_info(" ", "weak refs", _remark_weak_ref_times); | |
| 2681 | |
| 2682 } | |
| 2683 print_ms_time_info(" ", "cleanups", _cleanup_times); | |
| 2684 gclog_or_tty->print_cr(" Final counting total time = %8.2f s (avg = %8.2f ms).", | |
| 2685 _total_counting_time, | |
| 2686 (_cleanup_times.num() > 0 ? _total_counting_time * 1000.0 / | |
| 2687 (double)_cleanup_times.num() | |
| 2688 : 0.0)); | |
| 2689 if (G1ScrubRemSets) { | |
| 2690 gclog_or_tty->print_cr(" RS scrub total time = %8.2f s (avg = %8.2f ms).", | |
| 2691 _total_rs_scrub_time, | |
| 2692 (_cleanup_times.num() > 0 ? _total_rs_scrub_time * 1000.0 / | |
| 2693 (double)_cleanup_times.num() | |
| 2694 : 0.0)); | |
| 2695 } | |
| 2696 gclog_or_tty->print_cr(" Total stop_world time = %8.2f s.", | |
| 2697 (_init_times.sum() + _remark_times.sum() + | |
| 2698 _cleanup_times.sum())/1000.0); | |
| 2699 gclog_or_tty->print_cr(" Total concurrent time = %8.2f s " | |
| 2700 "(%8.2f s marking, %8.2f s counting).", | |
| 2701 cmThread()->vtime_accum(), | |
| 2702 cmThread()->vtime_mark_accum(), | |
| 2703 cmThread()->vtime_count_accum()); | |
| 2704 } | |
| 2705 | |
| 2706 // Closures | |
| 2707 // XXX: there seems to be a lot of code duplication here; | |
| 2708 // should refactor and consolidate the shared code. | |
| 2709 | |
| 2710 // This closure is used to mark refs into the CMS generation in | |
| 2711 // the CMS bit map. Called at the first checkpoint. | |
| 2712 | |
| 2713 // We take a break if someone is trying to stop the world. | |
| 2714 bool ConcurrentMark::do_yield_check(int worker_i) { | |
| 2715 if (should_yield()) { | |
| 2716 if (worker_i == 0) | |
| 2717 _g1h->g1_policy()->record_concurrent_pause(); | |
| 2718 cmThread()->yield(); | |
| 2719 if (worker_i == 0) | |
| 2720 _g1h->g1_policy()->record_concurrent_pause_end(); | |
| 2721 return true; | |
| 2722 } else { | |
| 2723 return false; | |
| 2724 } | |
| 2725 } | |
| 2726 | |
| 2727 bool ConcurrentMark::should_yield() { | |
| 2728 return cmThread()->should_yield(); | |
| 2729 } | |
| 2730 | |
| 2731 bool ConcurrentMark::containing_card_is_marked(void* p) { | |
| 2732 size_t offset = pointer_delta(p, _g1h->reserved_region().start(), 1); | |
| 2733 return _card_bm.at(offset >> CardTableModRefBS::card_shift); | |
| 2734 } | |
| 2735 | |
| 2736 bool ConcurrentMark::containing_cards_are_marked(void* start, | |
| 2737 void* last) { | |
| 2738 return | |
| 2739 containing_card_is_marked(start) && | |
| 2740 containing_card_is_marked(last); | |
| 2741 } | |
| 2742 | |
| 2743 #ifndef PRODUCT | |
| 2744 // for debugging purposes | |
| 2745 void ConcurrentMark::print_finger() { | |
| 2746 gclog_or_tty->print_cr("heap ["PTR_FORMAT", "PTR_FORMAT"), global finger = "PTR_FORMAT, | |
| 2747 _heap_start, _heap_end, _finger); | |
| 2748 for (int i = 0; i < (int) _max_task_num; ++i) { | |
| 2749 gclog_or_tty->print(" %d: "PTR_FORMAT, i, _tasks[i]->finger()); | |
| 2750 } | |
| 2751 gclog_or_tty->print_cr(""); | |
| 2752 } | |
| 2753 #endif | |
| 2754 | |
| 2755 // Closure for iteration over bitmaps | |
| 2756 class CMBitMapClosure : public BitMapClosure { | |
| 2757 private: | |
| 2758 // the bitmap that is being iterated over | |
| 2759 CMBitMap* _nextMarkBitMap; | |
| 2760 ConcurrentMark* _cm; | |
| 2761 CMTask* _task; | |
| 2762 // true if we're scanning a heap region claimed by the task (so that | |
| 2763 // we move the finger along), false if we're not, i.e. currently when | |
| 2764 // scanning a heap region popped from the region stack (so that we | |
| 2765 // do not move the task finger along; it'd be a mistake if we did so). | |
| 2766 bool _scanning_heap_region; | |
| 2767 | |
| 2768 public: | |
| 2769 CMBitMapClosure(CMTask *task, | |
| 2770 ConcurrentMark* cm, | |
| 2771 CMBitMap* nextMarkBitMap) | |
| 2772 : _task(task), _cm(cm), _nextMarkBitMap(nextMarkBitMap) { } | |
| 2773 | |
| 2774 void set_scanning_heap_region(bool scanning_heap_region) { | |
| 2775 _scanning_heap_region = scanning_heap_region; | |
| 2776 } | |
| 2777 | |
| 2778 bool do_bit(size_t offset) { | |
| 2779 HeapWord* addr = _nextMarkBitMap->offsetToHeapWord(offset); | |
| 2780 tmp_guarantee_CM( _nextMarkBitMap->isMarked(addr), "invariant" ); | |
| 2781 tmp_guarantee_CM( addr < _cm->finger(), "invariant" ); | |
| 2782 | |
| 2783 if (_scanning_heap_region) { | |
| 2784 statsOnly( _task->increase_objs_found_on_bitmap() ); | |
| 2785 tmp_guarantee_CM( addr >= _task->finger(), "invariant" ); | |
| 2786 // We move that task's local finger along. | |
| 2787 _task->move_finger_to(addr); | |
| 2788 } else { | |
| 2789 // We move the task's region finger along. | |
| 2790 _task->move_region_finger_to(addr); | |
| 2791 } | |
| 2792 | |
| 2793 _task->scan_object(oop(addr)); | |
| 2794 // we only partially drain the local queue and global stack | |
| 2795 _task->drain_local_queue(true); | |
| 2796 _task->drain_global_stack(true); | |
| 2797 | |
| 2798 // if the has_aborted flag has been raised, we need to bail out of | |
| 2799 // the iteration | |
| 2800 return !_task->has_aborted(); | |
| 2801 } | |
| 2802 }; | |
| 2803 | |
| 2804 // Closure for iterating over objects, currently only used for | |
| 2805 // processing SATB buffers. | |
| 2806 class CMObjectClosure : public ObjectClosure { | |
| 2807 private: | |
| 2808 CMTask* _task; | |
| 2809 | |
| 2810 public: | |
| 2811 void do_object(oop obj) { | |
| 2812 _task->deal_with_reference(obj); | |
| 2813 } | |
| 2814 | |
| 2815 CMObjectClosure(CMTask* task) : _task(task) { } | |
| 2816 }; | |
| 2817 | |
| 2818 // Closure for iterating over object fields | |
| 2819 class CMOopClosure : public OopClosure { | |
| 2820 private: | |
| 2821 G1CollectedHeap* _g1h; | |
| 2822 ConcurrentMark* _cm; | |
| 2823 CMTask* _task; | |
| 2824 | |
| 2825 public: | |
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2826 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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2827 virtual void do_oop( oop* p) { do_oop_work(p); } |
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2828 |
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2829 template <class T> void do_oop_work(T* p) { |
| 342 | 2830 tmp_guarantee_CM( _g1h->is_in_g1_reserved((HeapWord*) p), "invariant" ); |
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2831 tmp_guarantee_CM( !_g1h->heap_region_containing((HeapWord*) p)->is_on_free_list(), "invariant" ); |
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2832 |
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2833 oop obj = oopDesc::load_decode_heap_oop(p); |
| 342 | 2834 if (_cm->verbose_high()) |
| 2835 gclog_or_tty->print_cr("[%d] we're looking at location " | |
| 2836 "*"PTR_FORMAT" = "PTR_FORMAT, | |
| 2837 _task->task_id(), p, (void*) obj); | |
| 2838 _task->deal_with_reference(obj); | |
| 2839 } | |
| 2840 | |
| 2841 CMOopClosure(G1CollectedHeap* g1h, | |
| 2842 ConcurrentMark* cm, | |
| 2843 CMTask* task) | |
| 2844 : _g1h(g1h), _cm(cm), _task(task) { } | |
| 2845 }; | |
| 2846 | |
| 2847 void CMTask::setup_for_region(HeapRegion* hr) { | |
| 2848 tmp_guarantee_CM( hr != NULL && !hr->continuesHumongous(), | |
| 2849 "claim_region() should have filtered out continues humongous regions" ); | |
| 2850 | |
| 2851 if (_cm->verbose_low()) | |
| 2852 gclog_or_tty->print_cr("[%d] setting up for region "PTR_FORMAT, | |
| 2853 _task_id, hr); | |
| 2854 | |
| 2855 _curr_region = hr; | |
| 2856 _finger = hr->bottom(); | |
| 2857 update_region_limit(); | |
| 2858 } | |
| 2859 | |
| 2860 void CMTask::update_region_limit() { | |
| 2861 HeapRegion* hr = _curr_region; | |
| 2862 HeapWord* bottom = hr->bottom(); | |
| 2863 HeapWord* limit = hr->next_top_at_mark_start(); | |
| 2864 | |
| 2865 if (limit == bottom) { | |
| 2866 if (_cm->verbose_low()) | |
| 2867 gclog_or_tty->print_cr("[%d] found an empty region " | |
| 2868 "["PTR_FORMAT", "PTR_FORMAT")", | |
| 2869 _task_id, bottom, limit); | |
| 2870 // The region was collected underneath our feet. | |
| 2871 // We set the finger to bottom to ensure that the bitmap | |
| 2872 // iteration that will follow this will not do anything. | |
| 2873 // (this is not a condition that holds when we set the region up, | |
| 2874 // as the region is not supposed to be empty in the first place) | |
| 2875 _finger = bottom; | |
| 2876 } else if (limit >= _region_limit) { | |
| 2877 tmp_guarantee_CM( limit >= _finger, "peace of mind" ); | |
| 2878 } else { | |
| 2879 tmp_guarantee_CM( limit < _region_limit, "only way to get here" ); | |
| 2880 // This can happen under some pretty unusual circumstances. An | |
| 2881 // evacuation pause empties the region underneath our feet (NTAMS | |
| 2882 // at bottom). We then do some allocation in the region (NTAMS | |
| 2883 // stays at bottom), followed by the region being used as a GC | |
| 2884 // alloc region (NTAMS will move to top() and the objects | |
| 2885 // originally below it will be grayed). All objects now marked in | |
| 2886 // the region are explicitly grayed, if below the global finger, | |
| 2887 // and we do not need in fact to scan anything else. So, we simply | |
| 2888 // set _finger to be limit to ensure that the bitmap iteration | |
| 2889 // doesn't do anything. | |
| 2890 _finger = limit; | |
| 2891 } | |
| 2892 | |
| 2893 _region_limit = limit; | |
| 2894 } | |
| 2895 | |
| 2896 void CMTask::giveup_current_region() { | |
| 2897 tmp_guarantee_CM( _curr_region != NULL, "invariant" ); | |
| 2898 if (_cm->verbose_low()) | |
| 2899 gclog_or_tty->print_cr("[%d] giving up region "PTR_FORMAT, | |
| 2900 _task_id, _curr_region); | |
| 2901 clear_region_fields(); | |
| 2902 } | |
| 2903 | |
| 2904 void CMTask::clear_region_fields() { | |
| 2905 // Values for these three fields that indicate that we're not | |
| 2906 // holding on to a region. | |
| 2907 _curr_region = NULL; | |
| 2908 _finger = NULL; | |
| 2909 _region_limit = NULL; | |
| 2910 | |
| 2911 _region_finger = NULL; | |
| 2912 } | |
| 2913 | |
| 2914 void CMTask::reset(CMBitMap* nextMarkBitMap) { | |
| 2915 guarantee( nextMarkBitMap != NULL, "invariant" ); | |
| 2916 | |
| 2917 if (_cm->verbose_low()) | |
| 2918 gclog_or_tty->print_cr("[%d] resetting", _task_id); | |
| 2919 | |
| 2920 _nextMarkBitMap = nextMarkBitMap; | |
| 2921 clear_region_fields(); | |
| 2922 | |
| 2923 _calls = 0; | |
| 2924 _elapsed_time_ms = 0.0; | |
| 2925 _termination_time_ms = 0.0; | |
| 2926 _termination_start_time_ms = 0.0; | |
| 2927 | |
| 2928 #if _MARKING_STATS_ | |
| 2929 _local_pushes = 0; | |
| 2930 _local_pops = 0; | |
| 2931 _local_max_size = 0; | |
| 2932 _objs_scanned = 0; | |
| 2933 _global_pushes = 0; | |
| 2934 _global_pops = 0; | |
| 2935 _global_max_size = 0; | |
| 2936 _global_transfers_to = 0; | |
| 2937 _global_transfers_from = 0; | |
| 2938 _region_stack_pops = 0; | |
| 2939 _regions_claimed = 0; | |
| 2940 _objs_found_on_bitmap = 0; | |
| 2941 _satb_buffers_processed = 0; | |
| 2942 _steal_attempts = 0; | |
| 2943 _steals = 0; | |
| 2944 _aborted = 0; | |
| 2945 _aborted_overflow = 0; | |
| 2946 _aborted_cm_aborted = 0; | |
| 2947 _aborted_yield = 0; | |
| 2948 _aborted_timed_out = 0; | |
| 2949 _aborted_satb = 0; | |
| 2950 _aborted_termination = 0; | |
| 2951 #endif // _MARKING_STATS_ | |
| 2952 } | |
| 2953 | |
| 2954 bool CMTask::should_exit_termination() { | |
| 2955 regular_clock_call(); | |
| 2956 // This is called when we are in the termination protocol. We should | |
| 2957 // quit if, for some reason, this task wants to abort or the global | |
| 2958 // stack is not empty (this means that we can get work from it). | |
| 2959 return !_cm->mark_stack_empty() || has_aborted(); | |
| 2960 } | |
| 2961 | |
| 2962 // This determines whether the method below will check both the local | |
| 2963 // and global fingers when determining whether to push on the stack a | |
| 2964 // gray object (value 1) or whether it will only check the global one | |
| 2965 // (value 0). The tradeoffs are that the former will be a bit more | |
| 2966 // accurate and possibly push less on the stack, but it might also be | |
| 2967 // a little bit slower. | |
| 2968 | |
| 2969 #define _CHECK_BOTH_FINGERS_ 1 | |
| 2970 | |
| 2971 void CMTask::deal_with_reference(oop obj) { | |
| 2972 if (_cm->verbose_high()) | |
| 2973 gclog_or_tty->print_cr("[%d] we're dealing with reference = "PTR_FORMAT, | |
| 2974 _task_id, (void*) obj); | |
| 2975 | |
| 2976 ++_refs_reached; | |
| 2977 | |
| 2978 HeapWord* objAddr = (HeapWord*) obj; | |
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2979 assert(obj->is_oop_or_null(true /* ignore mark word */), "Error"); |
| 342 | 2980 if (_g1h->is_in_g1_reserved(objAddr)) { |
| 2981 tmp_guarantee_CM( obj != NULL, "is_in_g1_reserved should ensure this" ); | |
| 2982 HeapRegion* hr = _g1h->heap_region_containing(obj); | |
| 2983 if (_g1h->is_obj_ill(obj, hr)) { | |
| 2984 if (_cm->verbose_high()) | |
| 2985 gclog_or_tty->print_cr("[%d] "PTR_FORMAT" is not considered marked", | |
| 2986 _task_id, (void*) obj); | |
| 2987 | |
| 2988 // we need to mark it first | |
| 2989 if (_nextMarkBitMap->parMark(objAddr)) { | |
| 2990 // No OrderAccess:store_load() is needed. It is implicit in the | |
| 2991 // CAS done in parMark(objAddr) above | |
| 2992 HeapWord* global_finger = _cm->finger(); | |
| 2993 | |
| 2994 #if _CHECK_BOTH_FINGERS_ | |
| 2995 // we will check both the local and global fingers | |
| 2996 | |
| 2997 if (_finger != NULL && objAddr < _finger) { | |
| 2998 if (_cm->verbose_high()) | |
| 2999 gclog_or_tty->print_cr("[%d] below the local finger ("PTR_FORMAT"), " | |
| 3000 "pushing it", _task_id, _finger); | |
| 3001 push(obj); | |
| 3002 } else if (_curr_region != NULL && objAddr < _region_limit) { | |
| 3003 // do nothing | |
| 3004 } else if (objAddr < global_finger) { | |
| 3005 // Notice that the global finger might be moving forward | |
| 3006 // concurrently. This is not a problem. In the worst case, we | |
| 3007 // mark the object while it is above the global finger and, by | |
| 3008 // the time we read the global finger, it has moved forward | |
| 3009 // passed this object. In this case, the object will probably | |
| 3010 // be visited when a task is scanning the region and will also | |
| 3011 // be pushed on the stack. So, some duplicate work, but no | |
| 3012 // correctness problems. | |
| 3013 | |
| 3014 if (_cm->verbose_high()) | |
| 3015 gclog_or_tty->print_cr("[%d] below the global finger " | |
| 3016 "("PTR_FORMAT"), pushing it", | |
| 3017 _task_id, global_finger); | |
| 3018 push(obj); | |
| 3019 } else { | |
| 3020 // do nothing | |
| 3021 } | |
| 3022 #else // _CHECK_BOTH_FINGERS_ | |
| 3023 // we will only check the global finger | |
| 3024 | |
| 3025 if (objAddr < global_finger) { | |
| 3026 // see long comment above | |
| 3027 | |
| 3028 if (_cm->verbose_high()) | |
| 3029 gclog_or_tty->print_cr("[%d] below the global finger " | |
| 3030 "("PTR_FORMAT"), pushing it", | |
| 3031 _task_id, global_finger); | |
| 3032 push(obj); | |
| 3033 } | |
| 3034 #endif // _CHECK_BOTH_FINGERS_ | |
| 3035 } | |
| 3036 } | |
| 3037 } | |
| 3038 } | |
| 3039 | |
| 3040 void CMTask::push(oop obj) { | |
| 3041 HeapWord* objAddr = (HeapWord*) obj; | |
| 3042 tmp_guarantee_CM( _g1h->is_in_g1_reserved(objAddr), "invariant" ); | |
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3043 tmp_guarantee_CM( !_g1h->heap_region_containing(objAddr)->is_on_free_list(), "invariant" ); |
| 342 | 3044 tmp_guarantee_CM( !_g1h->is_obj_ill(obj), "invariant" ); |
| 3045 tmp_guarantee_CM( _nextMarkBitMap->isMarked(objAddr), "invariant" ); | |
| 3046 | |
| 3047 if (_cm->verbose_high()) | |
| 3048 gclog_or_tty->print_cr("[%d] pushing "PTR_FORMAT, _task_id, (void*) obj); | |
| 3049 | |
| 3050 if (!_task_queue->push(obj)) { | |
| 3051 // The local task queue looks full. We need to push some entries | |
| 3052 // to the global stack. | |
| 3053 | |
| 3054 if (_cm->verbose_medium()) | |
| 3055 gclog_or_tty->print_cr("[%d] task queue overflow, " | |
| 3056 "moving entries to the global stack", | |
| 3057 _task_id); | |
| 3058 move_entries_to_global_stack(); | |
| 3059 | |
| 3060 // this should succeed since, even if we overflow the global | |
| 3061 // stack, we should have definitely removed some entries from the | |
| 3062 // local queue. So, there must be space on it. | |
| 3063 bool success = _task_queue->push(obj); | |
| 3064 tmp_guarantee_CM( success, "invariant" ); | |
| 3065 } | |
| 3066 | |
| 3067 statsOnly( int tmp_size = _task_queue->size(); | |
| 3068 if (tmp_size > _local_max_size) | |
| 3069 _local_max_size = tmp_size; | |
| 3070 ++_local_pushes ); | |
| 3071 } | |
| 3072 | |
| 3073 void CMTask::reached_limit() { | |
| 3074 tmp_guarantee_CM( _words_scanned >= _words_scanned_limit || | |
| 3075 _refs_reached >= _refs_reached_limit , | |
| 3076 "shouldn't have been called otherwise" ); | |
| 3077 regular_clock_call(); | |
| 3078 } | |
| 3079 | |
| 3080 void CMTask::regular_clock_call() { | |
| 3081 if (has_aborted()) | |
| 3082 return; | |
| 3083 | |
| 3084 // First, we need to recalculate the words scanned and refs reached | |
| 3085 // limits for the next clock call. | |
| 3086 recalculate_limits(); | |
| 3087 | |
| 3088 // During the regular clock call we do the following | |
| 3089 | |
| 3090 // (1) If an overflow has been flagged, then we abort. | |
| 3091 if (_cm->has_overflown()) { | |
| 3092 set_has_aborted(); | |
| 3093 return; | |
| 3094 } | |
| 3095 | |
| 3096 // If we are not concurrent (i.e. we're doing remark) we don't need | |
| 3097 // to check anything else. The other steps are only needed during | |
| 3098 // the concurrent marking phase. | |
| 3099 if (!concurrent()) | |
| 3100 return; | |
| 3101 | |
| 3102 // (2) If marking has been aborted for Full GC, then we also abort. | |
| 3103 if (_cm->has_aborted()) { | |
| 3104 set_has_aborted(); | |
| 3105 statsOnly( ++_aborted_cm_aborted ); | |
| 3106 return; | |
| 3107 } | |
| 3108 | |
| 3109 double curr_time_ms = os::elapsedVTime() * 1000.0; | |
| 3110 | |
| 3111 // (3) If marking stats are enabled, then we update the step history. | |
| 3112 #if _MARKING_STATS_ | |
| 3113 if (_words_scanned >= _words_scanned_limit) | |
| 3114 ++_clock_due_to_scanning; | |
| 3115 if (_refs_reached >= _refs_reached_limit) | |
| 3116 ++_clock_due_to_marking; | |
| 3117 | |
| 3118 double last_interval_ms = curr_time_ms - _interval_start_time_ms; | |
| 3119 _interval_start_time_ms = curr_time_ms; | |
| 3120 _all_clock_intervals_ms.add(last_interval_ms); | |
| 3121 | |
| 3122 if (_cm->verbose_medium()) { | |
| 3123 gclog_or_tty->print_cr("[%d] regular clock, interval = %1.2lfms, " | |
| 3124 "scanned = %d%s, refs reached = %d%s", | |
| 3125 _task_id, last_interval_ms, | |
| 3126 _words_scanned, | |
| 3127 (_words_scanned >= _words_scanned_limit) ? " (*)" : "", | |
| 3128 _refs_reached, | |
| 3129 (_refs_reached >= _refs_reached_limit) ? " (*)" : ""); | |
| 3130 } | |
| 3131 #endif // _MARKING_STATS_ | |
| 3132 | |
| 3133 // (4) We check whether we should yield. If we have to, then we abort. | |
| 3134 if (_cm->should_yield()) { | |
| 3135 // We should yield. To do this we abort the task. The caller is | |
| 3136 // responsible for yielding. | |
| 3137 set_has_aborted(); | |
| 3138 statsOnly( ++_aborted_yield ); | |
| 3139 return; | |
| 3140 } | |
| 3141 | |
| 3142 // (5) We check whether we've reached our time quota. If we have, | |
| 3143 // then we abort. | |
| 3144 double elapsed_time_ms = curr_time_ms - _start_time_ms; | |
| 3145 if (elapsed_time_ms > _time_target_ms) { | |
| 3146 set_has_aborted(); | |
| 3147 _has_aborted_timed_out = true; | |
| 3148 statsOnly( ++_aborted_timed_out ); | |
| 3149 return; | |
| 3150 } | |
| 3151 | |
| 3152 // (6) Finally, we check whether there are enough completed STAB | |
| 3153 // buffers available for processing. If there are, we abort. | |
| 3154 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 3155 if (!_draining_satb_buffers && satb_mq_set.process_completed_buffers()) { | |
| 3156 if (_cm->verbose_low()) | |
| 3157 gclog_or_tty->print_cr("[%d] aborting to deal with pending SATB buffers", | |
| 3158 _task_id); | |
| 3159 // we do need to process SATB buffers, we'll abort and restart | |
| 3160 // the marking task to do so | |
| 3161 set_has_aborted(); | |
| 3162 statsOnly( ++_aborted_satb ); | |
| 3163 return; | |
| 3164 } | |
| 3165 } | |
| 3166 | |
| 3167 void CMTask::recalculate_limits() { | |
| 3168 _real_words_scanned_limit = _words_scanned + words_scanned_period; | |
| 3169 _words_scanned_limit = _real_words_scanned_limit; | |
| 3170 | |
| 3171 _real_refs_reached_limit = _refs_reached + refs_reached_period; | |
| 3172 _refs_reached_limit = _real_refs_reached_limit; | |
| 3173 } | |
| 3174 | |
| 3175 void CMTask::decrease_limits() { | |
| 3176 // This is called when we believe that we're going to do an infrequent | |
| 3177 // operation which will increase the per byte scanned cost (i.e. move | |
| 3178 // entries to/from the global stack). It basically tries to decrease the | |
| 3179 // scanning limit so that the clock is called earlier. | |
| 3180 | |
| 3181 if (_cm->verbose_medium()) | |
| 3182 gclog_or_tty->print_cr("[%d] decreasing limits", _task_id); | |
| 3183 | |
| 3184 _words_scanned_limit = _real_words_scanned_limit - | |
| 3185 3 * words_scanned_period / 4; | |
| 3186 _refs_reached_limit = _real_refs_reached_limit - | |
| 3187 3 * refs_reached_period / 4; | |
| 3188 } | |
| 3189 | |
| 3190 void CMTask::move_entries_to_global_stack() { | |
| 3191 // local array where we'll store the entries that will be popped | |
| 3192 // from the local queue | |
| 3193 oop buffer[global_stack_transfer_size]; | |
| 3194 | |
| 3195 int n = 0; | |
| 3196 oop obj; | |
| 3197 while (n < global_stack_transfer_size && _task_queue->pop_local(obj)) { | |
| 3198 buffer[n] = obj; | |
| 3199 ++n; | |
| 3200 } | |
| 3201 | |
| 3202 if (n > 0) { | |
| 3203 // we popped at least one entry from the local queue | |
| 3204 | |
| 3205 statsOnly( ++_global_transfers_to; _local_pops += n ); | |
| 3206 | |
| 3207 if (!_cm->mark_stack_push(buffer, n)) { | |
| 3208 if (_cm->verbose_low()) | |
| 3209 gclog_or_tty->print_cr("[%d] aborting due to global stack overflow", _task_id); | |
| 3210 set_has_aborted(); | |
| 3211 } else { | |
| 3212 // the transfer was successful | |
| 3213 | |
| 3214 if (_cm->verbose_medium()) | |
| 3215 gclog_or_tty->print_cr("[%d] pushed %d entries to the global stack", | |
| 3216 _task_id, n); | |
| 3217 statsOnly( int tmp_size = _cm->mark_stack_size(); | |
| 3218 if (tmp_size > _global_max_size) | |
| 3219 _global_max_size = tmp_size; | |
| 3220 _global_pushes += n ); | |
| 3221 } | |
| 3222 } | |
| 3223 | |
| 3224 // this operation was quite expensive, so decrease the limits | |
| 3225 decrease_limits(); | |
| 3226 } | |
| 3227 | |
| 3228 void CMTask::get_entries_from_global_stack() { | |
| 3229 // local array where we'll store the entries that will be popped | |
| 3230 // from the global stack. | |
| 3231 oop buffer[global_stack_transfer_size]; | |
| 3232 int n; | |
| 3233 _cm->mark_stack_pop(buffer, global_stack_transfer_size, &n); | |
| 3234 tmp_guarantee_CM( n <= global_stack_transfer_size, | |
| 3235 "we should not pop more than the given limit" ); | |
| 3236 if (n > 0) { | |
| 3237 // yes, we did actually pop at least one entry | |
| 3238 | |
| 3239 statsOnly( ++_global_transfers_from; _global_pops += n ); | |
| 3240 if (_cm->verbose_medium()) | |
| 3241 gclog_or_tty->print_cr("[%d] popped %d entries from the global stack", | |
| 3242 _task_id, n); | |
| 3243 for (int i = 0; i < n; ++i) { | |
| 3244 bool success = _task_queue->push(buffer[i]); | |
| 3245 // We only call this when the local queue is empty or under a | |
| 3246 // given target limit. So, we do not expect this push to fail. | |
| 3247 tmp_guarantee_CM( success, "invariant" ); | |
| 3248 } | |
| 3249 | |
| 3250 statsOnly( int tmp_size = _task_queue->size(); | |
| 3251 if (tmp_size > _local_max_size) | |
| 3252 _local_max_size = tmp_size; | |
| 3253 _local_pushes += n ); | |
| 3254 } | |
| 3255 | |
| 3256 // this operation was quite expensive, so decrease the limits | |
| 3257 decrease_limits(); | |
| 3258 } | |
| 3259 | |
| 3260 void CMTask::drain_local_queue(bool partially) { | |
| 3261 if (has_aborted()) | |
| 3262 return; | |
| 3263 | |
| 3264 // Decide what the target size is, depending whether we're going to | |
| 3265 // drain it partially (so that other tasks can steal if they run out | |
| 3266 // of things to do) or totally (at the very end). | |
| 3267 size_t target_size; | |
| 3268 if (partially) | |
| 3269 target_size = MIN2((size_t)_task_queue->max_elems()/3, GCDrainStackTargetSize); | |
| 3270 else | |
| 3271 target_size = 0; | |
| 3272 | |
| 3273 if (_task_queue->size() > target_size) { | |
| 3274 if (_cm->verbose_high()) | |
| 3275 gclog_or_tty->print_cr("[%d] draining local queue, target size = %d", | |
| 3276 _task_id, target_size); | |
| 3277 | |
| 3278 oop obj; | |
| 3279 bool ret = _task_queue->pop_local(obj); | |
| 3280 while (ret) { | |
| 3281 statsOnly( ++_local_pops ); | |
| 3282 | |
| 3283 if (_cm->verbose_high()) | |
| 3284 gclog_or_tty->print_cr("[%d] popped "PTR_FORMAT, _task_id, | |
| 3285 (void*) obj); | |
| 3286 | |
| 3287 tmp_guarantee_CM( _g1h->is_in_g1_reserved((HeapWord*) obj), | |
| 3288 "invariant" ); | |
|
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|
3289 tmp_guarantee_CM( !_g1h->heap_region_containing(obj)->is_on_free_list(), |
|
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|
3290 "invariant" ); |
| 342 | 3291 |
| 3292 scan_object(obj); | |
| 3293 | |
| 3294 if (_task_queue->size() <= target_size || has_aborted()) | |
| 3295 ret = false; | |
| 3296 else | |
| 3297 ret = _task_queue->pop_local(obj); | |
| 3298 } | |
| 3299 | |
| 3300 if (_cm->verbose_high()) | |
| 3301 gclog_or_tty->print_cr("[%d] drained local queue, size = %d", | |
| 3302 _task_id, _task_queue->size()); | |
| 3303 } | |
| 3304 } | |
| 3305 | |
| 3306 void CMTask::drain_global_stack(bool partially) { | |
| 3307 if (has_aborted()) | |
| 3308 return; | |
| 3309 | |
| 3310 // We have a policy to drain the local queue before we attempt to | |
| 3311 // drain the global stack. | |
| 3312 tmp_guarantee_CM( partially || _task_queue->size() == 0, "invariant" ); | |
| 3313 | |
| 3314 // Decide what the target size is, depending whether we're going to | |
| 3315 // drain it partially (so that other tasks can steal if they run out | |
| 3316 // of things to do) or totally (at the very end). Notice that, | |
| 3317 // because we move entries from the global stack in chunks or | |
| 3318 // because another task might be doing the same, we might in fact | |
| 3319 // drop below the target. But, this is not a problem. | |
| 3320 size_t target_size; | |
| 3321 if (partially) | |
| 3322 target_size = _cm->partial_mark_stack_size_target(); | |
| 3323 else | |
| 3324 target_size = 0; | |
| 3325 | |
| 3326 if (_cm->mark_stack_size() > target_size) { | |
| 3327 if (_cm->verbose_low()) | |
| 3328 gclog_or_tty->print_cr("[%d] draining global_stack, target size %d", | |
| 3329 _task_id, target_size); | |
| 3330 | |
| 3331 while (!has_aborted() && _cm->mark_stack_size() > target_size) { | |
| 3332 get_entries_from_global_stack(); | |
| 3333 drain_local_queue(partially); | |
| 3334 } | |
| 3335 | |
| 3336 if (_cm->verbose_low()) | |
| 3337 gclog_or_tty->print_cr("[%d] drained global stack, size = %d", | |
| 3338 _task_id, _cm->mark_stack_size()); | |
| 3339 } | |
| 3340 } | |
| 3341 | |
| 3342 // SATB Queue has several assumptions on whether to call the par or | |
| 3343 // non-par versions of the methods. this is why some of the code is | |
| 3344 // replicated. We should really get rid of the single-threaded version | |
| 3345 // of the code to simplify things. | |
| 3346 void CMTask::drain_satb_buffers() { | |
| 3347 if (has_aborted()) | |
| 3348 return; | |
| 3349 | |
| 3350 // We set this so that the regular clock knows that we're in the | |
| 3351 // middle of draining buffers and doesn't set the abort flag when it | |
| 3352 // notices that SATB buffers are available for draining. It'd be | |
| 3353 // very counter productive if it did that. :-) | |
| 3354 _draining_satb_buffers = true; | |
| 3355 | |
| 3356 CMObjectClosure oc(this); | |
| 3357 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 3358 if (ParallelGCThreads > 0) | |
| 3359 satb_mq_set.set_par_closure(_task_id, &oc); | |
| 3360 else | |
| 3361 satb_mq_set.set_closure(&oc); | |
| 3362 | |
| 3363 // This keeps claiming and applying the closure to completed buffers | |
| 3364 // until we run out of buffers or we need to abort. | |
| 3365 if (ParallelGCThreads > 0) { | |
| 3366 while (!has_aborted() && | |
| 3367 satb_mq_set.par_apply_closure_to_completed_buffer(_task_id)) { | |
| 3368 if (_cm->verbose_medium()) | |
| 3369 gclog_or_tty->print_cr("[%d] processed an SATB buffer", _task_id); | |
| 3370 statsOnly( ++_satb_buffers_processed ); | |
| 3371 regular_clock_call(); | |
| 3372 } | |
| 3373 } else { | |
| 3374 while (!has_aborted() && | |
| 3375 satb_mq_set.apply_closure_to_completed_buffer()) { | |
| 3376 if (_cm->verbose_medium()) | |
| 3377 gclog_or_tty->print_cr("[%d] processed an SATB buffer", _task_id); | |
| 3378 statsOnly( ++_satb_buffers_processed ); | |
| 3379 regular_clock_call(); | |
| 3380 } | |
| 3381 } | |
| 3382 | |
| 3383 if (!concurrent() && !has_aborted()) { | |
| 3384 // We should only do this during remark. | |
| 3385 if (ParallelGCThreads > 0) | |
| 3386 satb_mq_set.par_iterate_closure_all_threads(_task_id); | |
| 3387 else | |
| 3388 satb_mq_set.iterate_closure_all_threads(); | |
| 3389 } | |
| 3390 | |
| 3391 _draining_satb_buffers = false; | |
| 3392 | |
| 3393 tmp_guarantee_CM( has_aborted() || | |
| 3394 concurrent() || | |
| 3395 satb_mq_set.completed_buffers_num() == 0, "invariant" ); | |
| 3396 | |
| 3397 if (ParallelGCThreads > 0) | |
| 3398 satb_mq_set.set_par_closure(_task_id, NULL); | |
| 3399 else | |
| 3400 satb_mq_set.set_closure(NULL); | |
| 3401 | |
| 3402 // again, this was a potentially expensive operation, decrease the | |
| 3403 // limits to get the regular clock call early | |
| 3404 decrease_limits(); | |
| 3405 } | |
| 3406 | |
| 3407 void CMTask::drain_region_stack(BitMapClosure* bc) { | |
| 3408 if (has_aborted()) | |
| 3409 return; | |
| 3410 | |
| 3411 tmp_guarantee_CM( _region_finger == NULL, | |
| 3412 "it should be NULL when we're not scanning a region" ); | |
| 3413 | |
| 3414 if (!_cm->region_stack_empty()) { | |
| 3415 if (_cm->verbose_low()) | |
| 3416 gclog_or_tty->print_cr("[%d] draining region stack, size = %d", | |
| 3417 _task_id, _cm->region_stack_size()); | |
| 3418 | |
| 3419 MemRegion mr = _cm->region_stack_pop(); | |
| 3420 // it returns MemRegion() if the pop fails | |
| 3421 statsOnly(if (mr.start() != NULL) ++_region_stack_pops ); | |
| 3422 | |
| 3423 while (mr.start() != NULL) { | |
| 3424 if (_cm->verbose_medium()) | |
| 3425 gclog_or_tty->print_cr("[%d] we are scanning region " | |
| 3426 "["PTR_FORMAT", "PTR_FORMAT")", | |
| 3427 _task_id, mr.start(), mr.end()); | |
| 3428 tmp_guarantee_CM( mr.end() <= _cm->finger(), | |
| 3429 "otherwise the region shouldn't be on the stack" ); | |
| 3430 assert(!mr.is_empty(), "Only non-empty regions live on the region stack"); | |
| 3431 if (_nextMarkBitMap->iterate(bc, mr)) { | |
| 3432 tmp_guarantee_CM( !has_aborted(), | |
| 3433 "cannot abort the task without aborting the bitmap iteration" ); | |
| 3434 | |
| 3435 // We finished iterating over the region without aborting. | |
| 3436 regular_clock_call(); | |
| 3437 if (has_aborted()) | |
| 3438 mr = MemRegion(); | |
| 3439 else { | |
| 3440 mr = _cm->region_stack_pop(); | |
| 3441 // it returns MemRegion() if the pop fails | |
| 3442 statsOnly(if (mr.start() != NULL) ++_region_stack_pops ); | |
| 3443 } | |
| 3444 } else { | |
| 3445 guarantee( has_aborted(), "currently the only way to do so" ); | |
| 3446 | |
| 3447 // The only way to abort the bitmap iteration is to return | |
| 3448 // false from the do_bit() method. However, inside the | |
| 3449 // do_bit() method we move the _region_finger to point to the | |
| 3450 // object currently being looked at. So, if we bail out, we | |
| 3451 // have definitely set _region_finger to something non-null. | |
| 3452 guarantee( _region_finger != NULL, "invariant" ); | |
| 3453 | |
| 3454 // The iteration was actually aborted. So now _region_finger | |
| 3455 // points to the address of the object we last scanned. If we | |
| 3456 // leave it there, when we restart this task, we will rescan | |
| 3457 // the object. It is easy to avoid this. We move the finger by | |
| 3458 // enough to point to the next possible object header (the | |
| 3459 // bitmap knows by how much we need to move it as it knows its | |
| 3460 // granularity). | |
| 3461 MemRegion newRegion = | |
| 3462 MemRegion(_nextMarkBitMap->nextWord(_region_finger), mr.end()); | |
| 3463 | |
| 3464 if (!newRegion.is_empty()) { | |
| 3465 if (_cm->verbose_low()) { | |
| 3466 gclog_or_tty->print_cr("[%d] pushing unscanned region" | |
| 3467 "[" PTR_FORMAT "," PTR_FORMAT ") on region stack", | |
| 3468 _task_id, | |
| 3469 newRegion.start(), newRegion.end()); | |
| 3470 } | |
| 3471 // Now push the part of the region we didn't scan on the | |
| 3472 // region stack to make sure a task scans it later. | |
| 3473 _cm->region_stack_push(newRegion); | |
| 3474 } | |
| 3475 // break from while | |
| 3476 mr = MemRegion(); | |
| 3477 } | |
| 3478 _region_finger = NULL; | |
| 3479 } | |
| 3480 | |
| 3481 // We only push regions on the region stack during evacuation | |
| 3482 // pauses. So if we come out the above iteration because we region | |
| 3483 // stack is empty, it will remain empty until the next yield | |
| 3484 // point. So, the guarantee below is safe. | |
| 3485 guarantee( has_aborted() || _cm->region_stack_empty(), | |
| 3486 "only way to exit the loop" ); | |
| 3487 | |
| 3488 if (_cm->verbose_low()) | |
| 3489 gclog_or_tty->print_cr("[%d] drained region stack, size = %d", | |
| 3490 _task_id, _cm->region_stack_size()); | |
| 3491 } | |
| 3492 } | |
| 3493 | |
| 3494 void CMTask::print_stats() { | |
| 3495 gclog_or_tty->print_cr("Marking Stats, task = %d, calls = %d", | |
| 3496 _task_id, _calls); | |
| 3497 gclog_or_tty->print_cr(" Elapsed time = %1.2lfms, Termination time = %1.2lfms", | |
| 3498 _elapsed_time_ms, _termination_time_ms); | |
| 3499 gclog_or_tty->print_cr(" Step Times (cum): num = %d, avg = %1.2lfms, sd = %1.2lfms", | |
| 3500 _step_times_ms.num(), _step_times_ms.avg(), | |
| 3501 _step_times_ms.sd()); | |
| 3502 gclog_or_tty->print_cr(" max = %1.2lfms, total = %1.2lfms", | |
| 3503 _step_times_ms.maximum(), _step_times_ms.sum()); | |
| 3504 | |
| 3505 #if _MARKING_STATS_ | |
| 3506 gclog_or_tty->print_cr(" Clock Intervals (cum): num = %d, avg = %1.2lfms, sd = %1.2lfms", | |
| 3507 _all_clock_intervals_ms.num(), _all_clock_intervals_ms.avg(), | |
| 3508 _all_clock_intervals_ms.sd()); | |
| 3509 gclog_or_tty->print_cr(" max = %1.2lfms, total = %1.2lfms", | |
| 3510 _all_clock_intervals_ms.maximum(), | |
| 3511 _all_clock_intervals_ms.sum()); | |
| 3512 gclog_or_tty->print_cr(" Clock Causes (cum): scanning = %d, marking = %d", | |
| 3513 _clock_due_to_scanning, _clock_due_to_marking); | |
| 3514 gclog_or_tty->print_cr(" Objects: scanned = %d, found on the bitmap = %d", | |
| 3515 _objs_scanned, _objs_found_on_bitmap); | |
| 3516 gclog_or_tty->print_cr(" Local Queue: pushes = %d, pops = %d, max size = %d", | |
| 3517 _local_pushes, _local_pops, _local_max_size); | |
| 3518 gclog_or_tty->print_cr(" Global Stack: pushes = %d, pops = %d, max size = %d", | |
| 3519 _global_pushes, _global_pops, _global_max_size); | |
| 3520 gclog_or_tty->print_cr(" transfers to = %d, transfers from = %d", | |
| 3521 _global_transfers_to,_global_transfers_from); | |
| 3522 gclog_or_tty->print_cr(" Regions: claimed = %d, Region Stack: pops = %d", | |
| 3523 _regions_claimed, _region_stack_pops); | |
| 3524 gclog_or_tty->print_cr(" SATB buffers: processed = %d", _satb_buffers_processed); | |
| 3525 gclog_or_tty->print_cr(" Steals: attempts = %d, successes = %d", | |
| 3526 _steal_attempts, _steals); | |
| 3527 gclog_or_tty->print_cr(" Aborted: %d, due to", _aborted); | |
| 3528 gclog_or_tty->print_cr(" overflow: %d, global abort: %d, yield: %d", | |
| 3529 _aborted_overflow, _aborted_cm_aborted, _aborted_yield); | |
| 3530 gclog_or_tty->print_cr(" time out: %d, SATB: %d, termination: %d", | |
| 3531 _aborted_timed_out, _aborted_satb, _aborted_termination); | |
| 3532 #endif // _MARKING_STATS_ | |
| 3533 } | |
| 3534 | |
| 3535 /***************************************************************************** | |
| 3536 | |
| 3537 The do_marking_step(time_target_ms) method is the building block | |
| 3538 of the parallel marking framework. It can be called in parallel | |
| 3539 with other invocations of do_marking_step() on different tasks | |
| 3540 (but only one per task, obviously) and concurrently with the | |
| 3541 mutator threads, or during remark, hence it eliminates the need | |
| 3542 for two versions of the code. When called during remark, it will | |
| 3543 pick up from where the task left off during the concurrent marking | |
| 3544 phase. Interestingly, tasks are also claimable during evacuation | |
| 3545 pauses too, since do_marking_step() ensures that it aborts before | |
| 3546 it needs to yield. | |
| 3547 | |
| 3548 The data structures that is uses to do marking work are the | |
| 3549 following: | |
| 3550 | |
| 3551 (1) Marking Bitmap. If there are gray objects that appear only | |
| 3552 on the bitmap (this happens either when dealing with an overflow | |
| 3553 or when the initial marking phase has simply marked the roots | |
| 3554 and didn't push them on the stack), then tasks claim heap | |
| 3555 regions whose bitmap they then scan to find gray objects. A | |
| 3556 global finger indicates where the end of the last claimed region | |
| 3557 is. A local finger indicates how far into the region a task has | |
| 3558 scanned. The two fingers are used to determine how to gray an | |
| 3559 object (i.e. whether simply marking it is OK, as it will be | |
| 3560 visited by a task in the future, or whether it needs to be also | |
| 3561 pushed on a stack). | |
| 3562 | |
| 3563 (2) Local Queue. The local queue of the task which is accessed | |
| 3564 reasonably efficiently by the task. Other tasks can steal from | |
| 3565 it when they run out of work. Throughout the marking phase, a | |
| 3566 task attempts to keep its local queue short but not totally | |
| 3567 empty, so that entries are available for stealing by other | |
| 3568 tasks. Only when there is no more work, a task will totally | |
| 3569 drain its local queue. | |
| 3570 | |
| 3571 (3) Global Mark Stack. This handles local queue overflow. During | |
| 3572 marking only sets of entries are moved between it and the local | |
| 3573 queues, as access to it requires a mutex and more fine-grain | |
| 3574 interaction with it which might cause contention. If it | |
| 3575 overflows, then the marking phase should restart and iterate | |
| 3576 over the bitmap to identify gray objects. Throughout the marking | |
| 3577 phase, tasks attempt to keep the global mark stack at a small | |
| 3578 length but not totally empty, so that entries are available for | |
| 3579 popping by other tasks. Only when there is no more work, tasks | |
| 3580 will totally drain the global mark stack. | |
| 3581 | |
| 3582 (4) Global Region Stack. Entries on it correspond to areas of | |
| 3583 the bitmap that need to be scanned since they contain gray | |
| 3584 objects. Pushes on the region stack only happen during | |
| 3585 evacuation pauses and typically correspond to areas covered by | |
| 3586 GC LABS. If it overflows, then the marking phase should restart | |
| 3587 and iterate over the bitmap to identify gray objects. Tasks will | |
| 3588 try to totally drain the region stack as soon as possible. | |
| 3589 | |
| 3590 (5) SATB Buffer Queue. This is where completed SATB buffers are | |
| 3591 made available. Buffers are regularly removed from this queue | |
| 3592 and scanned for roots, so that the queue doesn't get too | |
| 3593 long. During remark, all completed buffers are processed, as | |
| 3594 well as the filled in parts of any uncompleted buffers. | |
| 3595 | |
| 3596 The do_marking_step() method tries to abort when the time target | |
| 3597 has been reached. There are a few other cases when the | |
| 3598 do_marking_step() method also aborts: | |
| 3599 | |
| 3600 (1) When the marking phase has been aborted (after a Full GC). | |
| 3601 | |
| 3602 (2) When a global overflow (either on the global stack or the | |
| 3603 region stack) has been triggered. Before the task aborts, it | |
| 3604 will actually sync up with the other tasks to ensure that all | |
| 3605 the marking data structures (local queues, stacks, fingers etc.) | |
| 3606 are re-initialised so that when do_marking_step() completes, | |
| 3607 the marking phase can immediately restart. | |
| 3608 | |
| 3609 (3) When enough completed SATB buffers are available. The | |
| 3610 do_marking_step() method only tries to drain SATB buffers right | |
| 3611 at the beginning. So, if enough buffers are available, the | |
| 3612 marking step aborts and the SATB buffers are processed at | |
| 3613 the beginning of the next invocation. | |
| 3614 | |
| 3615 (4) To yield. when we have to yield then we abort and yield | |
| 3616 right at the end of do_marking_step(). This saves us from a lot | |
| 3617 of hassle as, by yielding we might allow a Full GC. If this | |
| 3618 happens then objects will be compacted underneath our feet, the | |
| 3619 heap might shrink, etc. We save checking for this by just | |
| 3620 aborting and doing the yield right at the end. | |
| 3621 | |
| 3622 From the above it follows that the do_marking_step() method should | |
| 3623 be called in a loop (or, otherwise, regularly) until it completes. | |
| 3624 | |
| 3625 If a marking step completes without its has_aborted() flag being | |
| 3626 true, it means it has completed the current marking phase (and | |
| 3627 also all other marking tasks have done so and have all synced up). | |
| 3628 | |
| 3629 A method called regular_clock_call() is invoked "regularly" (in | |
| 3630 sub ms intervals) throughout marking. It is this clock method that | |
| 3631 checks all the abort conditions which were mentioned above and | |
| 3632 decides when the task should abort. A work-based scheme is used to | |
| 3633 trigger this clock method: when the number of object words the | |
| 3634 marking phase has scanned or the number of references the marking | |
| 3635 phase has visited reach a given limit. Additional invocations to | |
| 3636 the method clock have been planted in a few other strategic places | |
| 3637 too. The initial reason for the clock method was to avoid calling | |
| 3638 vtime too regularly, as it is quite expensive. So, once it was in | |
| 3639 place, it was natural to piggy-back all the other conditions on it | |
| 3640 too and not constantly check them throughout the code. | |
| 3641 | |
| 3642 *****************************************************************************/ | |
| 3643 | |
| 3644 void CMTask::do_marking_step(double time_target_ms) { | |
| 3645 guarantee( time_target_ms >= 1.0, "minimum granularity is 1ms" ); | |
| 3646 guarantee( concurrent() == _cm->concurrent(), "they should be the same" ); | |
| 3647 | |
| 3648 guarantee( concurrent() || _cm->region_stack_empty(), | |
| 3649 "the region stack should have been cleared before remark" ); | |
| 3650 guarantee( _region_finger == NULL, | |
| 3651 "this should be non-null only when a region is being scanned" ); | |
| 3652 | |
| 3653 G1CollectorPolicy* g1_policy = _g1h->g1_policy(); | |
| 3654 guarantee( _task_queues != NULL, "invariant" ); | |
| 3655 guarantee( _task_queue != NULL, "invariant" ); | |
| 3656 guarantee( _task_queues->queue(_task_id) == _task_queue, "invariant" ); | |
| 3657 | |
| 3658 guarantee( !_claimed, | |
| 3659 "only one thread should claim this task at any one time" ); | |
| 3660 | |
| 3661 // OK, this doesn't safeguard again all possible scenarios, as it is | |
| 3662 // possible for two threads to set the _claimed flag at the same | |
| 3663 // time. But it is only for debugging purposes anyway and it will | |
| 3664 // catch most problems. | |
| 3665 _claimed = true; | |
| 3666 | |
| 3667 _start_time_ms = os::elapsedVTime() * 1000.0; | |
| 3668 statsOnly( _interval_start_time_ms = _start_time_ms ); | |
| 3669 | |
| 3670 double diff_prediction_ms = | |
| 3671 g1_policy->get_new_prediction(&_marking_step_diffs_ms); | |
| 3672 _time_target_ms = time_target_ms - diff_prediction_ms; | |
| 3673 | |
| 3674 // set up the variables that are used in the work-based scheme to | |
| 3675 // call the regular clock method | |
| 3676 _words_scanned = 0; | |
| 3677 _refs_reached = 0; | |
| 3678 recalculate_limits(); | |
| 3679 | |
| 3680 // clear all flags | |
| 3681 clear_has_aborted(); | |
| 3682 _has_aborted_timed_out = false; | |
| 3683 _draining_satb_buffers = false; | |
| 3684 | |
| 3685 ++_calls; | |
| 3686 | |
| 3687 if (_cm->verbose_low()) | |
| 3688 gclog_or_tty->print_cr("[%d] >>>>>>>>>> START, call = %d, " | |
| 3689 "target = %1.2lfms >>>>>>>>>>", | |
| 3690 _task_id, _calls, _time_target_ms); | |
| 3691 | |
| 3692 // Set up the bitmap and oop closures. Anything that uses them is | |
| 3693 // eventually called from this method, so it is OK to allocate these | |
| 3694 // statically. | |
| 3695 CMBitMapClosure bitmap_closure(this, _cm, _nextMarkBitMap); | |
| 3696 CMOopClosure oop_closure(_g1h, _cm, this); | |
| 3697 set_oop_closure(&oop_closure); | |
| 3698 | |
| 3699 if (_cm->has_overflown()) { | |
| 3700 // This can happen if the region stack or the mark stack overflows | |
| 3701 // during a GC pause and this task, after a yield point, | |
| 3702 // restarts. We have to abort as we need to get into the overflow | |
| 3703 // protocol which happens right at the end of this task. | |
| 3704 set_has_aborted(); | |
| 3705 } | |
| 3706 | |
| 3707 // First drain any available SATB buffers. After this, we will not | |
| 3708 // look at SATB buffers before the next invocation of this method. | |
| 3709 // If enough completed SATB buffers are queued up, the regular clock | |
| 3710 // will abort this task so that it restarts. | |
| 3711 drain_satb_buffers(); | |
| 3712 // ...then partially drain the local queue and the global stack | |
| 3713 drain_local_queue(true); | |
| 3714 drain_global_stack(true); | |
| 3715 | |
| 3716 // Then totally drain the region stack. We will not look at | |
| 3717 // it again before the next invocation of this method. Entries on | |
| 3718 // the region stack are only added during evacuation pauses, for | |
| 3719 // which we have to yield. When we do, we abort the task anyway so | |
| 3720 // it will look at the region stack again when it restarts. | |
| 3721 bitmap_closure.set_scanning_heap_region(false); | |
| 3722 drain_region_stack(&bitmap_closure); | |
| 3723 // ...then partially drain the local queue and the global stack | |
| 3724 drain_local_queue(true); | |
| 3725 drain_global_stack(true); | |
| 3726 | |
| 3727 do { | |
| 3728 if (!has_aborted() && _curr_region != NULL) { | |
| 3729 // This means that we're already holding on to a region. | |
| 3730 tmp_guarantee_CM( _finger != NULL, | |
| 3731 "if region is not NULL, then the finger " | |
| 3732 "should not be NULL either" ); | |
| 3733 | |
| 3734 // We might have restarted this task after an evacuation pause | |
| 3735 // which might have evacuated the region we're holding on to | |
| 3736 // underneath our feet. Let's read its limit again to make sure | |
| 3737 // that we do not iterate over a region of the heap that | |
| 3738 // contains garbage (update_region_limit() will also move | |
| 3739 // _finger to the start of the region if it is found empty). | |
| 3740 update_region_limit(); | |
| 3741 // We will start from _finger not from the start of the region, | |
| 3742 // as we might be restarting this task after aborting half-way | |
| 3743 // through scanning this region. In this case, _finger points to | |
| 3744 // the address where we last found a marked object. If this is a | |
| 3745 // fresh region, _finger points to start(). | |
| 3746 MemRegion mr = MemRegion(_finger, _region_limit); | |
| 3747 | |
| 3748 if (_cm->verbose_low()) | |
| 3749 gclog_or_tty->print_cr("[%d] we're scanning part " | |
| 3750 "["PTR_FORMAT", "PTR_FORMAT") " | |
| 3751 "of region "PTR_FORMAT, | |
| 3752 _task_id, _finger, _region_limit, _curr_region); | |
| 3753 | |
| 3754 // Let's iterate over the bitmap of the part of the | |
| 3755 // region that is left. | |
| 3756 bitmap_closure.set_scanning_heap_region(true); | |
| 3757 if (mr.is_empty() || | |
| 3758 _nextMarkBitMap->iterate(&bitmap_closure, mr)) { | |
| 3759 // We successfully completed iterating over the region. Now, | |
| 3760 // let's give up the region. | |
| 3761 giveup_current_region(); | |
| 3762 regular_clock_call(); | |
| 3763 } else { | |
| 3764 guarantee( has_aborted(), "currently the only way to do so" ); | |
| 3765 // The only way to abort the bitmap iteration is to return | |
| 3766 // false from the do_bit() method. However, inside the | |
| 3767 // do_bit() method we move the _finger to point to the | |
| 3768 // object currently being looked at. So, if we bail out, we | |
| 3769 // have definitely set _finger to something non-null. | |
| 3770 guarantee( _finger != NULL, "invariant" ); | |
| 3771 | |
| 3772 // Region iteration was actually aborted. So now _finger | |
| 3773 // points to the address of the object we last scanned. If we | |
| 3774 // leave it there, when we restart this task, we will rescan | |
| 3775 // the object. It is easy to avoid this. We move the finger by | |
| 3776 // enough to point to the next possible object header (the | |
| 3777 // bitmap knows by how much we need to move it as it knows its | |
| 3778 // granularity). | |
| 3779 move_finger_to(_nextMarkBitMap->nextWord(_finger)); | |
| 3780 } | |
| 3781 } | |
| 3782 // At this point we have either completed iterating over the | |
| 3783 // region we were holding on to, or we have aborted. | |
| 3784 | |
| 3785 // We then partially drain the local queue and the global stack. | |
| 3786 // (Do we really need this?) | |
| 3787 drain_local_queue(true); | |
| 3788 drain_global_stack(true); | |
| 3789 | |
| 3790 // Read the note on the claim_region() method on why it might | |
| 3791 // return NULL with potentially more regions available for | |
| 3792 // claiming and why we have to check out_of_regions() to determine | |
| 3793 // whether we're done or not. | |
| 3794 while (!has_aborted() && _curr_region == NULL && !_cm->out_of_regions()) { | |
| 3795 // We are going to try to claim a new region. We should have | |
| 3796 // given up on the previous one. | |
| 3797 tmp_guarantee_CM( _curr_region == NULL && | |
| 3798 _finger == NULL && | |
| 3799 _region_limit == NULL, "invariant" ); | |
| 3800 if (_cm->verbose_low()) | |
| 3801 gclog_or_tty->print_cr("[%d] trying to claim a new region", _task_id); | |
| 3802 HeapRegion* claimed_region = _cm->claim_region(_task_id); | |
| 3803 if (claimed_region != NULL) { | |
| 3804 // Yes, we managed to claim one | |
| 3805 statsOnly( ++_regions_claimed ); | |
| 3806 | |
| 3807 if (_cm->verbose_low()) | |
| 3808 gclog_or_tty->print_cr("[%d] we successfully claimed " | |
| 3809 "region "PTR_FORMAT, | |
| 3810 _task_id, claimed_region); | |
| 3811 | |
| 3812 setup_for_region(claimed_region); | |
| 3813 tmp_guarantee_CM( _curr_region == claimed_region, "invariant" ); | |
| 3814 } | |
| 3815 // It is important to call the regular clock here. It might take | |
| 3816 // a while to claim a region if, for example, we hit a large | |
| 3817 // block of empty regions. So we need to call the regular clock | |
| 3818 // method once round the loop to make sure it's called | |
| 3819 // frequently enough. | |
| 3820 regular_clock_call(); | |
| 3821 } | |
| 3822 | |
| 3823 if (!has_aborted() && _curr_region == NULL) { | |
| 3824 tmp_guarantee_CM( _cm->out_of_regions(), | |
| 3825 "at this point we should be out of regions" ); | |
| 3826 } | |
| 3827 } while ( _curr_region != NULL && !has_aborted()); | |
| 3828 | |
| 3829 if (!has_aborted()) { | |
| 3830 // We cannot check whether the global stack is empty, since other | |
|
343
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|
3831 // tasks might be pushing objects to it concurrently. We also cannot |
|
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|
3832 // check if the region stack is empty because if a thread is aborting |
|
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|
3833 // it can push a partially done region back. |
|
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|
3834 tmp_guarantee_CM( _cm->out_of_regions(), |
| 342 | 3835 "at this point we should be out of regions" ); |
| 3836 | |
| 3837 if (_cm->verbose_low()) | |
| 3838 gclog_or_tty->print_cr("[%d] all regions claimed", _task_id); | |
| 3839 | |
| 3840 // Try to reduce the number of available SATB buffers so that | |
| 3841 // remark has less work to do. | |
| 3842 drain_satb_buffers(); | |
| 3843 } | |
| 3844 | |
| 3845 // Since we've done everything else, we can now totally drain the | |
| 3846 // local queue and global stack. | |
| 3847 drain_local_queue(false); | |
| 3848 drain_global_stack(false); | |
| 3849 | |
| 3850 // Attempt at work stealing from other task's queues. | |
| 3851 if (!has_aborted()) { | |
| 3852 // We have not aborted. This means that we have finished all that | |
| 3853 // we could. Let's try to do some stealing... | |
| 3854 | |
| 3855 // We cannot check whether the global stack is empty, since other | |
|
343
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|
3856 // tasks might be pushing objects to it concurrently. We also cannot |
|
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|
3857 // check if the region stack is empty because if a thread is aborting |
|
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|
3858 // it can push a partially done region back. |
| 342 | 3859 guarantee( _cm->out_of_regions() && |
| 3860 _task_queue->size() == 0, "only way to reach here" ); | |
| 3861 | |
| 3862 if (_cm->verbose_low()) | |
| 3863 gclog_or_tty->print_cr("[%d] starting to steal", _task_id); | |
| 3864 | |
| 3865 while (!has_aborted()) { | |
| 3866 oop obj; | |
| 3867 statsOnly( ++_steal_attempts ); | |
| 3868 | |
| 3869 if (_cm->try_stealing(_task_id, &_hash_seed, obj)) { | |
| 3870 if (_cm->verbose_medium()) | |
| 3871 gclog_or_tty->print_cr("[%d] stolen "PTR_FORMAT" successfully", | |
| 3872 _task_id, (void*) obj); | |
| 3873 | |
| 3874 statsOnly( ++_steals ); | |
| 3875 | |
| 3876 tmp_guarantee_CM( _nextMarkBitMap->isMarked((HeapWord*) obj), | |
| 3877 "any stolen object should be marked" ); | |
| 3878 scan_object(obj); | |
| 3879 | |
| 3880 // And since we're towards the end, let's totally drain the | |
| 3881 // local queue and global stack. | |
| 3882 drain_local_queue(false); | |
| 3883 drain_global_stack(false); | |
| 3884 } else { | |
| 3885 break; | |
| 3886 } | |
| 3887 } | |
| 3888 } | |
| 3889 | |
| 3890 // We still haven't aborted. Now, let's try to get into the | |
| 3891 // termination protocol. | |
| 3892 if (!has_aborted()) { | |
| 3893 // We cannot check whether the global stack is empty, since other | |
|
343
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|
3894 // tasks might be concurrently pushing objects on it. We also cannot |
|
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|
3895 // check if the region stack is empty because if a thread is aborting |
|
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|
3896 // it can push a partially done region back. |
| 342 | 3897 guarantee( _cm->out_of_regions() && |
| 3898 _task_queue->size() == 0, "only way to reach here" ); | |
| 3899 | |
| 3900 if (_cm->verbose_low()) | |
| 3901 gclog_or_tty->print_cr("[%d] starting termination protocol", _task_id); | |
| 3902 | |
| 3903 _termination_start_time_ms = os::elapsedVTime() * 1000.0; | |
| 3904 // The CMTask class also extends the TerminatorTerminator class, | |
| 3905 // hence its should_exit_termination() method will also decide | |
| 3906 // whether to exit the termination protocol or not. | |
| 3907 bool finished = _cm->terminator()->offer_termination(this); | |
| 3908 double termination_end_time_ms = os::elapsedVTime() * 1000.0; | |
| 3909 _termination_time_ms += | |
| 3910 termination_end_time_ms - _termination_start_time_ms; | |
| 3911 | |
| 3912 if (finished) { | |
| 3913 // We're all done. | |
| 3914 | |
| 3915 if (_task_id == 0) { | |
| 3916 // let's allow task 0 to do this | |
| 3917 if (concurrent()) { | |
| 3918 guarantee( _cm->concurrent_marking_in_progress(), "invariant" ); | |
| 3919 // we need to set this to false before the next | |
| 3920 // safepoint. This way we ensure that the marking phase | |
| 3921 // doesn't observe any more heap expansions. | |
| 3922 _cm->clear_concurrent_marking_in_progress(); | |
| 3923 } | |
| 3924 } | |
| 3925 | |
| 3926 // We can now guarantee that the global stack is empty, since | |
| 3927 // all other tasks have finished. | |
| 3928 guarantee( _cm->out_of_regions() && | |
| 3929 _cm->region_stack_empty() && | |
| 3930 _cm->mark_stack_empty() && | |
| 3931 _task_queue->size() == 0 && | |
| 3932 !_cm->has_overflown() && | |
| 3933 !_cm->mark_stack_overflow() && | |
| 3934 !_cm->region_stack_overflow(), | |
| 3935 "only way to reach here" ); | |
| 3936 | |
| 3937 if (_cm->verbose_low()) | |
| 3938 gclog_or_tty->print_cr("[%d] all tasks terminated", _task_id); | |
| 3939 } else { | |
| 3940 // Apparently there's more work to do. Let's abort this task. It | |
| 3941 // will restart it and we can hopefully find more things to do. | |
| 3942 | |
| 3943 if (_cm->verbose_low()) | |
| 3944 gclog_or_tty->print_cr("[%d] apparently there is more work to do", _task_id); | |
| 3945 | |
| 3946 set_has_aborted(); | |
| 3947 statsOnly( ++_aborted_termination ); | |
| 3948 } | |
| 3949 } | |
| 3950 | |
| 3951 // Mainly for debugging purposes to make sure that a pointer to the | |
| 3952 // closure which was statically allocated in this frame doesn't | |
| 3953 // escape it by accident. | |
| 3954 set_oop_closure(NULL); | |
| 3955 double end_time_ms = os::elapsedVTime() * 1000.0; | |
| 3956 double elapsed_time_ms = end_time_ms - _start_time_ms; | |
| 3957 // Update the step history. | |
| 3958 _step_times_ms.add(elapsed_time_ms); | |
| 3959 | |
| 3960 if (has_aborted()) { | |
| 3961 // The task was aborted for some reason. | |
| 3962 | |
| 3963 statsOnly( ++_aborted ); | |
| 3964 | |
| 3965 if (_has_aborted_timed_out) { | |
| 3966 double diff_ms = elapsed_time_ms - _time_target_ms; | |
| 3967 // Keep statistics of how well we did with respect to hitting | |
| 3968 // our target only if we actually timed out (if we aborted for | |
| 3969 // other reasons, then the results might get skewed). | |
| 3970 _marking_step_diffs_ms.add(diff_ms); | |
| 3971 } | |
| 3972 | |
| 3973 if (_cm->has_overflown()) { | |
| 3974 // This is the interesting one. We aborted because a global | |
| 3975 // overflow was raised. This means we have to restart the | |
| 3976 // marking phase and start iterating over regions. However, in | |
| 3977 // order to do this we have to make sure that all tasks stop | |
| 3978 // what they are doing and re-initialise in a safe manner. We | |
| 3979 // will achieve this with the use of two barrier sync points. | |
| 3980 | |
| 3981 if (_cm->verbose_low()) | |
| 3982 gclog_or_tty->print_cr("[%d] detected overflow", _task_id); | |
| 3983 | |
| 3984 _cm->enter_first_sync_barrier(_task_id); | |
| 3985 // When we exit this sync barrier we know that all tasks have | |
| 3986 // stopped doing marking work. So, it's now safe to | |
| 3987 // re-initialise our data structures. At the end of this method, | |
| 3988 // task 0 will clear the global data structures. | |
| 3989 | |
| 3990 statsOnly( ++_aborted_overflow ); | |
| 3991 | |
| 3992 // We clear the local state of this task... | |
| 3993 clear_region_fields(); | |
| 3994 | |
| 3995 // ...and enter the second barrier. | |
| 3996 _cm->enter_second_sync_barrier(_task_id); | |
| 3997 // At this point everything has bee re-initialised and we're | |
| 3998 // ready to restart. | |
| 3999 } | |
| 4000 | |
| 4001 if (_cm->verbose_low()) { | |
| 4002 gclog_or_tty->print_cr("[%d] <<<<<<<<<< ABORTING, target = %1.2lfms, " | |
| 4003 "elapsed = %1.2lfms <<<<<<<<<<", | |
| 4004 _task_id, _time_target_ms, elapsed_time_ms); | |
| 4005 if (_cm->has_aborted()) | |
| 4006 gclog_or_tty->print_cr("[%d] ========== MARKING ABORTED ==========", | |
| 4007 _task_id); | |
| 4008 } | |
| 4009 } else { | |
| 4010 if (_cm->verbose_low()) | |
| 4011 gclog_or_tty->print_cr("[%d] <<<<<<<<<< FINISHED, target = %1.2lfms, " | |
| 4012 "elapsed = %1.2lfms <<<<<<<<<<", | |
| 4013 _task_id, _time_target_ms, elapsed_time_ms); | |
| 4014 } | |
| 4015 | |
| 4016 _claimed = false; | |
| 4017 } | |
| 4018 | |
| 4019 CMTask::CMTask(int task_id, | |
| 4020 ConcurrentMark* cm, | |
| 4021 CMTaskQueue* task_queue, | |
| 4022 CMTaskQueueSet* task_queues) | |
| 4023 : _g1h(G1CollectedHeap::heap()), | |
| 4024 _co_tracker(G1CMGroup), | |
| 4025 _task_id(task_id), _cm(cm), | |
| 4026 _claimed(false), | |
| 4027 _nextMarkBitMap(NULL), _hash_seed(17), | |
| 4028 _task_queue(task_queue), | |
| 4029 _task_queues(task_queues), | |
| 4030 _oop_closure(NULL) { | |
| 4031 guarantee( task_queue != NULL, "invariant" ); | |
| 4032 guarantee( task_queues != NULL, "invariant" ); | |
| 4033 | |
| 4034 statsOnly( _clock_due_to_scanning = 0; | |
| 4035 _clock_due_to_marking = 0 ); | |
| 4036 | |
| 4037 _marking_step_diffs_ms.add(0.5); | |
| 4038 } |