Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/g1/concurrentMark.cpp @ 1833:8b10f48633dc
6984287: Regularize how GC parallel workers are specified.
Summary: Associate number of GC workers with the workgang as opposed to the task.
Reviewed-by: johnc, ysr
| author | jmasa |
|---|---|
| date | Mon, 20 Sep 2010 14:38:38 -0700 |
| parents | b63010841f78 |
| children | 4805b9f4779e |
| rev | line source |
|---|---|
| 342 | 1 /* |
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2 * Copyright (c) 2001, 2009, Oracle and/or its affiliates. All rights reserved. |
| 342 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 342 | 22 * |
| 23 */ | |
| 24 | |
| 25 #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; | |
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240 assert(ind < _capacity, "By overflow test above."); |
| 342 | 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 | |
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300 // Currently we do not call this at all. Normally we would call it |
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301 // during the concurrent marking / remark phases but we now call |
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302 // the lock-based version instead. But we might want to resurrect this |
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303 // code in the future. So, we'll leave it here commented out. |
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304 #if 0 |
| 342 | 305 MemRegion CMRegionStack::pop() { |
| 306 while (true) { | |
| 307 // Otherwise... | |
| 308 jint index = _index; | |
| 309 | |
| 310 if (index == 0) { | |
| 311 return MemRegion(); | |
| 312 } | |
| 313 jint next_index = index-1; | |
| 314 jint res = Atomic::cmpxchg(next_index, &_index, index); | |
| 315 if (res == index) { | |
| 316 MemRegion mr = _base[next_index]; | |
| 317 if (mr.start() != NULL) { | |
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318 assert(mr.end() != NULL, "invariant"); |
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319 assert(mr.word_size() > 0, "invariant"); |
| 342 | 320 return mr; |
| 321 } else { | |
| 322 // that entry was invalidated... let's skip it | |
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323 assert(mr.end() == NULL, "invariant"); |
| 342 | 324 } |
| 325 } | |
| 326 // Otherwise, we need to try again. | |
| 327 } | |
| 328 } | |
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329 #endif // 0 |
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330 |
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331 void CMRegionStack::push_with_lock(MemRegion mr) { |
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332 assert(mr.word_size() > 0, "Precondition"); |
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333 MutexLockerEx x(CMRegionStack_lock, Mutex::_no_safepoint_check_flag); |
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334 |
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335 if (isFull()) { |
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336 _overflow = true; |
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337 return; |
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338 } |
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339 |
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340 _base[_index] = mr; |
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341 _index += 1; |
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342 } |
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343 |
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344 MemRegion CMRegionStack::pop_with_lock() { |
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345 MutexLockerEx x(CMRegionStack_lock, Mutex::_no_safepoint_check_flag); |
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346 |
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347 while (true) { |
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348 if (_index == 0) { |
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349 return MemRegion(); |
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350 } |
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351 _index -= 1; |
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352 |
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353 MemRegion mr = _base[_index]; |
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354 if (mr.start() != NULL) { |
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355 assert(mr.end() != NULL, "invariant"); |
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356 assert(mr.word_size() > 0, "invariant"); |
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357 return mr; |
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358 } else { |
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359 // that entry was invalidated... let's skip it |
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360 assert(mr.end() == NULL, "invariant"); |
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361 } |
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362 } |
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363 } |
| 342 | 364 |
| 365 bool CMRegionStack::invalidate_entries_into_cset() { | |
| 366 bool result = false; | |
| 367 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 368 for (int i = 0; i < _oops_do_bound; ++i) { | |
| 369 MemRegion mr = _base[i]; | |
| 370 if (mr.start() != NULL) { | |
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371 assert(mr.end() != NULL, "invariant"); |
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372 assert(mr.word_size() > 0, "invariant"); |
| 342 | 373 HeapRegion* hr = g1h->heap_region_containing(mr.start()); |
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374 assert(hr != NULL, "invariant"); |
| 342 | 375 if (hr->in_collection_set()) { |
| 376 // The region points into the collection set | |
| 377 _base[i] = MemRegion(); | |
| 378 result = true; | |
| 379 } | |
| 380 } else { | |
| 381 // that entry was invalidated... let's skip it | |
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382 assert(mr.end() == NULL, "invariant"); |
| 342 | 383 } |
| 384 } | |
| 385 return result; | |
| 386 } | |
| 387 | |
| 388 template<class OopClosureClass> | |
| 389 bool CMMarkStack::drain(OopClosureClass* cl, CMBitMap* bm, bool yield_after) { | |
| 390 assert(!_drain_in_progress || !_drain_in_progress_yields || yield_after | |
| 391 || SafepointSynchronize::is_at_safepoint(), | |
| 392 "Drain recursion must be yield-safe."); | |
| 393 bool res = true; | |
| 394 debug_only(_drain_in_progress = true); | |
| 395 debug_only(_drain_in_progress_yields = yield_after); | |
| 396 while (!isEmpty()) { | |
| 397 oop newOop = pop(); | |
| 398 assert(G1CollectedHeap::heap()->is_in_reserved(newOop), "Bad pop"); | |
| 399 assert(newOop->is_oop(), "Expected an oop"); | |
| 400 assert(bm == NULL || bm->isMarked((HeapWord*)newOop), | |
| 401 "only grey objects on this stack"); | |
| 402 // iterate over the oops in this oop, marking and pushing | |
| 403 // the ones in CMS generation. | |
| 404 newOop->oop_iterate(cl); | |
| 405 if (yield_after && _cm->do_yield_check()) { | |
| 406 res = false; break; | |
| 407 } | |
| 408 } | |
| 409 debug_only(_drain_in_progress = false); | |
| 410 return res; | |
| 411 } | |
| 412 | |
| 413 void CMMarkStack::oops_do(OopClosure* f) { | |
| 414 if (_index == 0) return; | |
| 415 assert(_oops_do_bound != -1 && _oops_do_bound <= _index, | |
| 416 "Bound must be set."); | |
| 417 for (int i = 0; i < _oops_do_bound; i++) { | |
| 418 f->do_oop(&_base[i]); | |
| 419 } | |
| 420 _oops_do_bound = -1; | |
| 421 } | |
| 422 | |
| 423 bool ConcurrentMark::not_yet_marked(oop obj) const { | |
| 424 return (_g1h->is_obj_ill(obj) | |
| 425 || (_g1h->is_in_permanent(obj) | |
| 426 && !nextMarkBitMap()->isMarked((HeapWord*)obj))); | |
| 427 } | |
| 428 | |
| 429 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away | |
| 430 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list | |
| 431 #endif // _MSC_VER | |
| 432 | |
| 433 ConcurrentMark::ConcurrentMark(ReservedSpace rs, | |
| 434 int max_regions) : | |
| 435 _markBitMap1(rs, MinObjAlignment - 1), | |
| 436 _markBitMap2(rs, MinObjAlignment - 1), | |
| 437 | |
| 438 _parallel_marking_threads(0), | |
| 439 _sleep_factor(0.0), | |
| 440 _marking_task_overhead(1.0), | |
| 441 _cleanup_sleep_factor(0.0), | |
| 442 _cleanup_task_overhead(1.0), | |
| 443 _region_bm(max_regions, false /* in_resource_area*/), | |
| 444 _card_bm((rs.size() + CardTableModRefBS::card_size - 1) >> | |
| 445 CardTableModRefBS::card_shift, | |
| 446 false /* in_resource_area*/), | |
| 447 _prevMarkBitMap(&_markBitMap1), | |
| 448 _nextMarkBitMap(&_markBitMap2), | |
| 449 _at_least_one_mark_complete(false), | |
| 450 | |
| 451 _markStack(this), | |
| 452 _regionStack(), | |
| 453 // _finger set in set_non_marking_state | |
| 454 | |
| 455 _max_task_num(MAX2(ParallelGCThreads, (size_t)1)), | |
| 456 // _active_tasks set in set_non_marking_state | |
| 457 // _tasks set inside the constructor | |
| 458 _task_queues(new CMTaskQueueSet((int) _max_task_num)), | |
| 459 _terminator(ParallelTaskTerminator((int) _max_task_num, _task_queues)), | |
| 460 | |
| 461 _has_overflown(false), | |
| 462 _concurrent(false), | |
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463 _has_aborted(false), |
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464 _restart_for_overflow(false), |
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465 _concurrent_marking_in_progress(false), |
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466 _should_gray_objects(false), |
| 342 | 467 |
| 468 // _verbose_level set below | |
| 469 | |
| 470 _init_times(), | |
| 471 _remark_times(), _remark_mark_times(), _remark_weak_ref_times(), | |
| 472 _cleanup_times(), | |
| 473 _total_counting_time(0.0), | |
| 474 _total_rs_scrub_time(0.0), | |
| 475 | |
| 936 | 476 _parallel_workers(NULL) |
| 342 | 477 { |
| 478 CMVerboseLevel verbose_level = | |
| 479 (CMVerboseLevel) G1MarkingVerboseLevel; | |
| 480 if (verbose_level < no_verbose) | |
| 481 verbose_level = no_verbose; | |
| 482 if (verbose_level > high_verbose) | |
| 483 verbose_level = high_verbose; | |
| 484 _verbose_level = verbose_level; | |
| 485 | |
| 486 if (verbose_low()) | |
| 487 gclog_or_tty->print_cr("[global] init, heap start = "PTR_FORMAT", " | |
| 488 "heap end = "PTR_FORMAT, _heap_start, _heap_end); | |
| 489 | |
| 1284 | 490 _markStack.allocate(MarkStackSize); |
| 751 | 491 _regionStack.allocate(G1MarkRegionStackSize); |
| 342 | 492 |
| 493 // Create & start a ConcurrentMark thread. | |
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494 _cmThread = new ConcurrentMarkThread(this); |
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495 assert(cmThread() != NULL, "CM Thread should have been created"); |
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496 assert(cmThread()->cm() != NULL, "CM Thread should refer to this cm"); |
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497 |
| 342 | 498 _g1h = G1CollectedHeap::heap(); |
| 499 assert(CGC_lock != NULL, "Where's the CGC_lock?"); | |
| 500 assert(_markBitMap1.covers(rs), "_markBitMap1 inconsistency"); | |
| 501 assert(_markBitMap2.covers(rs), "_markBitMap2 inconsistency"); | |
| 502 | |
| 503 SATBMarkQueueSet& satb_qs = JavaThread::satb_mark_queue_set(); | |
| 1282 | 504 satb_qs.set_buffer_size(G1SATBBufferSize); |
| 342 | 505 |
| 506 int size = (int) MAX2(ParallelGCThreads, (size_t)1); | |
| 507 _par_cleanup_thread_state = NEW_C_HEAP_ARRAY(ParCleanupThreadState*, size); | |
| 508 for (int i = 0 ; i < size; i++) { | |
| 509 _par_cleanup_thread_state[i] = new ParCleanupThreadState; | |
| 510 } | |
| 511 | |
| 512 _tasks = NEW_C_HEAP_ARRAY(CMTask*, _max_task_num); | |
| 513 _accum_task_vtime = NEW_C_HEAP_ARRAY(double, _max_task_num); | |
| 514 | |
| 515 // so that the assertion in MarkingTaskQueue::task_queue doesn't fail | |
| 516 _active_tasks = _max_task_num; | |
| 517 for (int i = 0; i < (int) _max_task_num; ++i) { | |
| 518 CMTaskQueue* task_queue = new CMTaskQueue(); | |
| 519 task_queue->initialize(); | |
| 520 _task_queues->register_queue(i, task_queue); | |
| 521 | |
| 522 _tasks[i] = new CMTask(i, this, task_queue, _task_queues); | |
| 523 _accum_task_vtime[i] = 0.0; | |
| 524 } | |
| 525 | |
| 1284 | 526 if (ConcGCThreads > ParallelGCThreads) { |
| 527 vm_exit_during_initialization("Can't have more ConcGCThreads " | |
| 342 | 528 "than ParallelGCThreads."); |
| 529 } | |
| 530 if (ParallelGCThreads == 0) { | |
| 531 // if we are not running with any parallel GC threads we will not | |
| 532 // spawn any marking threads either | |
| 533 _parallel_marking_threads = 0; | |
| 534 _sleep_factor = 0.0; | |
| 535 _marking_task_overhead = 1.0; | |
| 536 } else { | |
| 1284 | 537 if (ConcGCThreads > 0) { |
| 538 // notice that ConcGCThreads overwrites G1MarkingOverheadPercent | |
| 342 | 539 // if both are set |
| 540 | |
| 1284 | 541 _parallel_marking_threads = ConcGCThreads; |
| 342 | 542 _sleep_factor = 0.0; |
| 543 _marking_task_overhead = 1.0; | |
| 751 | 544 } else if (G1MarkingOverheadPercent > 0) { |
| 342 | 545 // we will calculate the number of parallel marking threads |
| 546 // based on a target overhead with respect to the soft real-time | |
| 547 // goal | |
| 548 | |
| 751 | 549 double marking_overhead = (double) G1MarkingOverheadPercent / 100.0; |
| 342 | 550 double overall_cm_overhead = |
| 751 | 551 (double) MaxGCPauseMillis * marking_overhead / |
| 552 (double) GCPauseIntervalMillis; | |
| 342 | 553 double cpu_ratio = 1.0 / (double) os::processor_count(); |
| 554 double marking_thread_num = ceil(overall_cm_overhead / cpu_ratio); | |
| 555 double marking_task_overhead = | |
| 556 overall_cm_overhead / marking_thread_num * | |
| 557 (double) os::processor_count(); | |
| 558 double sleep_factor = | |
| 559 (1.0 - marking_task_overhead) / marking_task_overhead; | |
| 560 | |
| 561 _parallel_marking_threads = (size_t) marking_thread_num; | |
| 562 _sleep_factor = sleep_factor; | |
| 563 _marking_task_overhead = marking_task_overhead; | |
| 564 } else { | |
| 565 _parallel_marking_threads = MAX2((ParallelGCThreads + 2) / 4, (size_t)1); | |
| 566 _sleep_factor = 0.0; | |
| 567 _marking_task_overhead = 1.0; | |
| 568 } | |
| 569 | |
| 570 if (parallel_marking_threads() > 1) | |
| 571 _cleanup_task_overhead = 1.0; | |
| 572 else | |
| 573 _cleanup_task_overhead = marking_task_overhead(); | |
| 574 _cleanup_sleep_factor = | |
| 575 (1.0 - cleanup_task_overhead()) / cleanup_task_overhead(); | |
| 576 | |
| 577 #if 0 | |
| 578 gclog_or_tty->print_cr("Marking Threads %d", parallel_marking_threads()); | |
| 579 gclog_or_tty->print_cr("CM Marking Task Overhead %1.4lf", marking_task_overhead()); | |
| 580 gclog_or_tty->print_cr("CM Sleep Factor %1.4lf", sleep_factor()); | |
| 581 gclog_or_tty->print_cr("CL Marking Task Overhead %1.4lf", cleanup_task_overhead()); | |
| 582 gclog_or_tty->print_cr("CL Sleep Factor %1.4lf", cleanup_sleep_factor()); | |
| 583 #endif | |
| 584 | |
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585 guarantee(parallel_marking_threads() > 0, "peace of mind"); |
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586 _parallel_workers = new FlexibleWorkGang("G1 Parallel Marking Threads", |
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587 (int) _parallel_marking_threads, false, true); |
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588 if (_parallel_workers == NULL) { |
| 342 | 589 vm_exit_during_initialization("Failed necessary allocation."); |
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590 } else { |
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591 _parallel_workers->initialize_workers(); |
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592 } |
| 342 | 593 } |
| 594 | |
| 595 // so that the call below can read a sensible value | |
| 596 _heap_start = (HeapWord*) rs.base(); | |
| 597 set_non_marking_state(); | |
| 598 } | |
| 599 | |
| 600 void ConcurrentMark::update_g1_committed(bool force) { | |
| 601 // If concurrent marking is not in progress, then we do not need to | |
| 602 // update _heap_end. This has a subtle and important | |
| 603 // side-effect. Imagine that two evacuation pauses happen between | |
| 604 // marking completion and remark. The first one can grow the | |
| 605 // heap (hence now the finger is below the heap end). Then, the | |
| 606 // second one could unnecessarily push regions on the region | |
| 607 // stack. This causes the invariant that the region stack is empty | |
| 608 // at the beginning of remark to be false. By ensuring that we do | |
| 609 // not observe heap expansions after marking is complete, then we do | |
| 610 // not have this problem. | |
| 611 if (!concurrent_marking_in_progress() && !force) | |
| 612 return; | |
| 613 | |
| 614 MemRegion committed = _g1h->g1_committed(); | |
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615 assert(committed.start() == _heap_start, "start shouldn't change"); |
| 342 | 616 HeapWord* new_end = committed.end(); |
| 617 if (new_end > _heap_end) { | |
| 618 // The heap has been expanded. | |
| 619 | |
| 620 _heap_end = new_end; | |
| 621 } | |
| 622 // Notice that the heap can also shrink. However, this only happens | |
| 623 // during a Full GC (at least currently) and the entire marking | |
| 624 // phase will bail out and the task will not be restarted. So, let's | |
| 625 // do nothing. | |
| 626 } | |
| 627 | |
| 628 void ConcurrentMark::reset() { | |
| 629 // Starting values for these two. This should be called in a STW | |
| 630 // phase. CM will be notified of any future g1_committed expansions | |
| 631 // will be at the end of evacuation pauses, when tasks are | |
| 632 // inactive. | |
| 633 MemRegion committed = _g1h->g1_committed(); | |
| 634 _heap_start = committed.start(); | |
| 635 _heap_end = committed.end(); | |
| 636 | |
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637 // Separated the asserts so that we know which one fires. |
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638 assert(_heap_start != NULL, "heap bounds should look ok"); |
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639 assert(_heap_end != NULL, "heap bounds should look ok"); |
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640 assert(_heap_start < _heap_end, "heap bounds should look ok"); |
| 342 | 641 |
| 642 // reset all the marking data structures and any necessary flags | |
| 643 clear_marking_state(); | |
| 644 | |
| 645 if (verbose_low()) | |
| 646 gclog_or_tty->print_cr("[global] resetting"); | |
| 647 | |
| 648 // We do reset all of them, since different phases will use | |
| 649 // different number of active threads. So, it's easiest to have all | |
| 650 // of them ready. | |
| 651 for (int i = 0; i < (int) _max_task_num; ++i) | |
| 652 _tasks[i]->reset(_nextMarkBitMap); | |
| 653 | |
| 654 // we need this to make sure that the flag is on during the evac | |
| 655 // pause with initial mark piggy-backed | |
| 656 set_concurrent_marking_in_progress(); | |
| 657 } | |
| 658 | |
| 659 void ConcurrentMark::set_phase(size_t active_tasks, bool concurrent) { | |
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660 assert(active_tasks <= _max_task_num, "we should not have more"); |
| 342 | 661 |
| 662 _active_tasks = active_tasks; | |
| 663 // Need to update the three data structures below according to the | |
| 664 // number of active threads for this phase. | |
| 665 _terminator = ParallelTaskTerminator((int) active_tasks, _task_queues); | |
| 666 _first_overflow_barrier_sync.set_n_workers((int) active_tasks); | |
| 667 _second_overflow_barrier_sync.set_n_workers((int) active_tasks); | |
| 668 | |
| 669 _concurrent = concurrent; | |
| 670 // We propagate this to all tasks, not just the active ones. | |
| 671 for (int i = 0; i < (int) _max_task_num; ++i) | |
| 672 _tasks[i]->set_concurrent(concurrent); | |
| 673 | |
| 674 if (concurrent) { | |
| 675 set_concurrent_marking_in_progress(); | |
| 676 } else { | |
| 677 // We currently assume that the concurrent flag has been set to | |
| 678 // false before we start remark. At this point we should also be | |
| 679 // in a STW phase. | |
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680 assert(!concurrent_marking_in_progress(), "invariant"); |
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681 assert(_finger == _heap_end, "only way to get here"); |
| 342 | 682 update_g1_committed(true); |
| 683 } | |
| 684 } | |
| 685 | |
| 686 void ConcurrentMark::set_non_marking_state() { | |
| 687 // We set the global marking state to some default values when we're | |
| 688 // not doing marking. | |
| 689 clear_marking_state(); | |
| 690 _active_tasks = 0; | |
| 691 clear_concurrent_marking_in_progress(); | |
| 692 } | |
| 693 | |
| 694 ConcurrentMark::~ConcurrentMark() { | |
| 695 int size = (int) MAX2(ParallelGCThreads, (size_t)1); | |
| 696 for (int i = 0; i < size; i++) delete _par_cleanup_thread_state[i]; | |
| 697 FREE_C_HEAP_ARRAY(ParCleanupThreadState*, | |
| 698 _par_cleanup_thread_state); | |
| 699 | |
| 700 for (int i = 0; i < (int) _max_task_num; ++i) { | |
| 701 delete _task_queues->queue(i); | |
| 702 delete _tasks[i]; | |
| 703 } | |
| 704 delete _task_queues; | |
| 705 FREE_C_HEAP_ARRAY(CMTask*, _max_task_num); | |
| 706 } | |
| 707 | |
| 708 // This closure is used to mark refs into the g1 generation | |
| 709 // from external roots in the CMS bit map. | |
| 710 // Called at the first checkpoint. | |
| 711 // | |
| 712 | |
| 713 void ConcurrentMark::clearNextBitmap() { | |
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714 G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
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715 G1CollectorPolicy* g1p = g1h->g1_policy(); |
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716 |
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717 // Make sure that the concurrent mark thread looks to still be in |
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718 // the current cycle. |
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719 guarantee(cmThread()->during_cycle(), "invariant"); |
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720 |
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721 // We are finishing up the current cycle by clearing the next |
|
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722 // marking bitmap and getting it ready for the next cycle. During |
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723 // this time no other cycle can start. So, let's make sure that this |
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724 // is the case. |
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725 guarantee(!g1h->mark_in_progress(), "invariant"); |
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726 |
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727 // clear the mark bitmap (no grey objects to start with). |
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728 // We need to do this in chunks and offer to yield in between |
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729 // each chunk. |
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730 HeapWord* start = _nextMarkBitMap->startWord(); |
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731 HeapWord* end = _nextMarkBitMap->endWord(); |
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732 HeapWord* cur = start; |
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733 size_t chunkSize = M; |
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734 while (cur < end) { |
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735 HeapWord* next = cur + chunkSize; |
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736 if (next > end) |
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737 next = end; |
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738 MemRegion mr(cur,next); |
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739 _nextMarkBitMap->clearRange(mr); |
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740 cur = next; |
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741 do_yield_check(); |
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742 |
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743 // Repeat the asserts from above. We'll do them as asserts here to |
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744 // minimize their overhead on the product. However, we'll have |
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745 // them as guarantees at the beginning / end of the bitmap |
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746 // clearing to get some checking in the product. |
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747 assert(cmThread()->during_cycle(), "invariant"); |
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748 assert(!g1h->mark_in_progress(), "invariant"); |
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749 } |
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750 |
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751 // Repeat the asserts from above. |
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752 guarantee(cmThread()->during_cycle(), "invariant"); |
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753 guarantee(!g1h->mark_in_progress(), "invariant"); |
| 342 | 754 } |
| 755 | |
| 756 class NoteStartOfMarkHRClosure: public HeapRegionClosure { | |
| 757 public: | |
| 758 bool doHeapRegion(HeapRegion* r) { | |
| 759 if (!r->continuesHumongous()) { | |
| 760 r->note_start_of_marking(true); | |
| 761 } | |
| 762 return false; | |
| 763 } | |
| 764 }; | |
| 765 | |
| 766 void ConcurrentMark::checkpointRootsInitialPre() { | |
| 767 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 768 G1CollectorPolicy* g1p = g1h->g1_policy(); | |
| 769 | |
| 770 _has_aborted = false; | |
| 771 | |
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772 #ifndef PRODUCT |
| 1044 | 773 if (G1PrintReachableAtInitialMark) { |
| 1388 | 774 print_reachable("at-cycle-start", |
| 775 true /* use_prev_marking */, true /* all */); | |
| 1044 | 776 } |
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777 #endif |
| 342 | 778 |
| 779 // Initialise marking structures. This has to be done in a STW phase. | |
| 780 reset(); | |
| 781 } | |
| 782 | |
| 783 class CMMarkRootsClosure: public OopsInGenClosure { | |
| 784 private: | |
| 785 ConcurrentMark* _cm; | |
| 786 G1CollectedHeap* _g1h; | |
| 787 bool _do_barrier; | |
| 788 | |
| 789 public: | |
| 790 CMMarkRootsClosure(ConcurrentMark* cm, | |
| 791 G1CollectedHeap* g1h, | |
| 792 bool do_barrier) : _cm(cm), _g1h(g1h), | |
| 793 _do_barrier(do_barrier) { } | |
| 794 | |
|
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795 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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796 virtual void do_oop( oop* p) { do_oop_work(p); } |
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797 |
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798 template <class T> void do_oop_work(T* p) { |
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799 T heap_oop = oopDesc::load_heap_oop(p); |
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800 if (!oopDesc::is_null(heap_oop)) { |
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801 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); |
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802 assert(obj->is_oop() || obj->mark() == NULL, |
| 342 | 803 "expected an oop, possibly with mark word displaced"); |
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804 HeapWord* addr = (HeapWord*)obj; |
| 342 | 805 if (_g1h->is_in_g1_reserved(addr)) { |
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806 _cm->grayRoot(obj); |
| 342 | 807 } |
| 808 } | |
| 809 if (_do_barrier) { | |
| 810 assert(!_g1h->is_in_g1_reserved(p), | |
| 811 "Should be called on external roots"); | |
| 812 do_barrier(p); | |
| 813 } | |
| 814 } | |
| 815 }; | |
| 816 | |
| 817 void ConcurrentMark::checkpointRootsInitialPost() { | |
| 818 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 819 | |
| 820 // For each region note start of marking. | |
| 821 NoteStartOfMarkHRClosure startcl; | |
| 822 g1h->heap_region_iterate(&startcl); | |
| 823 | |
| 824 // Start weak-reference discovery. | |
| 825 ReferenceProcessor* rp = g1h->ref_processor(); | |
| 826 rp->verify_no_references_recorded(); | |
| 827 rp->enable_discovery(); // enable ("weak") refs discovery | |
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828 rp->setup_policy(false); // snapshot the soft ref policy to be used in this cycle |
| 342 | 829 |
| 830 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
|
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831 // This is the start of the marking cycle, we're expected all |
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832 // threads to have SATB queues with active set to false. |
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833 satb_mq_set.set_active_all_threads(true, /* new active value */ |
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834 false /* expected_active */); |
| 342 | 835 |
| 836 // update_g1_committed() will be called at the end of an evac pause | |
| 837 // when marking is on. So, it's also called at the end of the | |
| 838 // initial-mark pause to update the heap end, if the heap expands | |
| 839 // during it. No need to call it here. | |
| 840 } | |
| 841 | |
| 842 // Checkpoint the roots into this generation from outside | |
| 843 // this generation. [Note this initial checkpoint need only | |
| 844 // be approximate -- we'll do a catch up phase subsequently.] | |
| 845 void ConcurrentMark::checkpointRootsInitial() { | |
| 846 assert(SafepointSynchronize::is_at_safepoint(), "world should be stopped"); | |
| 847 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 848 | |
| 849 double start = os::elapsedTime(); | |
| 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 | |
| 883 g1p->record_concurrent_mark_init_end(); | |
| 884 } | |
| 885 | |
| 886 /* | |
| 887 Notice that in the next two methods, we actually leave the STS | |
| 888 during the barrier sync and join it immediately afterwards. If we | |
| 889 do not do this, this then the following deadlock can occur: one | |
| 890 thread could be in the barrier sync code, waiting for the other | |
| 891 thread to also sync up, whereas another one could be trying to | |
| 892 yield, while also waiting for the other threads to sync up too. | |
| 893 | |
| 894 Because the thread that does the sync barrier has left the STS, it | |
| 895 is possible to be suspended for a Full GC or an evacuation pause | |
| 896 could occur. This is actually safe, since the entering the sync | |
| 897 barrier is one of the last things do_marking_step() does, and it | |
| 898 doesn't manipulate any data structures afterwards. | |
| 899 */ | |
| 900 | |
| 901 void ConcurrentMark::enter_first_sync_barrier(int task_num) { | |
| 902 if (verbose_low()) | |
| 903 gclog_or_tty->print_cr("[%d] entering first barrier", task_num); | |
| 904 | |
| 905 ConcurrentGCThread::stsLeave(); | |
| 906 _first_overflow_barrier_sync.enter(); | |
| 907 ConcurrentGCThread::stsJoin(); | |
| 908 // at this point everyone should have synced up and not be doing any | |
| 909 // more work | |
| 910 | |
| 911 if (verbose_low()) | |
| 912 gclog_or_tty->print_cr("[%d] leaving first barrier", task_num); | |
| 913 | |
| 914 // let task 0 do this | |
| 915 if (task_num == 0) { | |
| 916 // task 0 is responsible for clearing the global data structures | |
| 917 clear_marking_state(); | |
| 918 | |
| 919 if (PrintGC) { | |
| 920 gclog_or_tty->date_stamp(PrintGCDateStamps); | |
| 921 gclog_or_tty->stamp(PrintGCTimeStamps); | |
| 922 gclog_or_tty->print_cr("[GC concurrent-mark-reset-for-overflow]"); | |
| 923 } | |
| 924 } | |
| 925 | |
| 926 // after this, each task should reset its own data structures then | |
| 927 // then go into the second barrier | |
| 928 } | |
| 929 | |
| 930 void ConcurrentMark::enter_second_sync_barrier(int task_num) { | |
| 931 if (verbose_low()) | |
| 932 gclog_or_tty->print_cr("[%d] entering second barrier", task_num); | |
| 933 | |
| 934 ConcurrentGCThread::stsLeave(); | |
| 935 _second_overflow_barrier_sync.enter(); | |
| 936 ConcurrentGCThread::stsJoin(); | |
| 937 // at this point everything should be re-initialised and ready to go | |
| 938 | |
| 939 if (verbose_low()) | |
| 940 gclog_or_tty->print_cr("[%d] leaving second barrier", task_num); | |
| 941 } | |
| 942 | |
| 943 void ConcurrentMark::grayRoot(oop p) { | |
| 944 HeapWord* addr = (HeapWord*) p; | |
| 945 // We can't really check against _heap_start and _heap_end, since it | |
| 946 // is possible during an evacuation pause with piggy-backed | |
| 947 // initial-mark that the committed space is expanded during the | |
| 948 // pause without CM observing this change. So the assertions below | |
| 949 // is a bit conservative; but better than nothing. | |
|
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950 assert(_g1h->g1_committed().contains(addr), |
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951 "address should be within the heap bounds"); |
| 342 | 952 |
| 953 if (!_nextMarkBitMap->isMarked(addr)) | |
| 954 _nextMarkBitMap->parMark(addr); | |
| 955 } | |
| 956 | |
| 957 void ConcurrentMark::grayRegionIfNecessary(MemRegion mr) { | |
| 958 // The objects on the region have already been marked "in bulk" by | |
| 959 // the caller. We only need to decide whether to push the region on | |
| 960 // the region stack or not. | |
| 961 | |
| 962 if (!concurrent_marking_in_progress() || !_should_gray_objects) | |
| 963 // We're done with marking and waiting for remark. We do not need to | |
| 964 // push anything else on the region stack. | |
| 965 return; | |
| 966 | |
| 967 HeapWord* finger = _finger; | |
| 968 | |
| 969 if (verbose_low()) | |
| 970 gclog_or_tty->print_cr("[global] attempting to push " | |
| 971 "region ["PTR_FORMAT", "PTR_FORMAT"), finger is at " | |
| 972 PTR_FORMAT, mr.start(), mr.end(), finger); | |
| 973 | |
| 974 if (mr.start() < finger) { | |
| 975 // The finger is always heap region aligned and it is not possible | |
| 976 // for mr to span heap regions. | |
|
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977 assert(mr.end() <= finger, "invariant"); |
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978 |
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979 // Separated the asserts so that we know which one fires. |
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980 assert(mr.start() <= mr.end(), |
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981 "region boundaries should fall within the committed space"); |
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982 assert(_heap_start <= mr.start(), |
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983 "region boundaries should fall within the committed space"); |
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984 assert(mr.end() <= _heap_end, |
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985 "region boundaries should fall within the committed space"); |
| 342 | 986 if (verbose_low()) |
| 987 gclog_or_tty->print_cr("[global] region ["PTR_FORMAT", "PTR_FORMAT") " | |
| 988 "below the finger, pushing it", | |
| 989 mr.start(), mr.end()); | |
| 990 | |
| 991 if (!region_stack_push(mr)) { | |
| 992 if (verbose_low()) | |
| 993 gclog_or_tty->print_cr("[global] region stack has overflown."); | |
| 994 } | |
| 995 } | |
| 996 } | |
| 997 | |
| 998 void ConcurrentMark::markAndGrayObjectIfNecessary(oop p) { | |
| 999 // The object is not marked by the caller. We need to at least mark | |
| 1000 // it and maybe push in on the stack. | |
| 1001 | |
| 1002 HeapWord* addr = (HeapWord*)p; | |
| 1003 if (!_nextMarkBitMap->isMarked(addr)) { | |
| 1004 // We definitely need to mark it, irrespective whether we bail out | |
| 1005 // because we're done with marking. | |
| 1006 if (_nextMarkBitMap->parMark(addr)) { | |
| 1007 if (!concurrent_marking_in_progress() || !_should_gray_objects) | |
| 1008 // If we're done with concurrent marking and we're waiting for | |
| 1009 // remark, then we're not pushing anything on the stack. | |
| 1010 return; | |
| 1011 | |
| 1012 // No OrderAccess:store_load() is needed. It is implicit in the | |
| 1013 // CAS done in parMark(addr) above | |
| 1014 HeapWord* finger = _finger; | |
| 1015 | |
| 1016 if (addr < finger) { | |
| 1017 if (!mark_stack_push(oop(addr))) { | |
| 1018 if (verbose_low()) | |
| 1019 gclog_or_tty->print_cr("[global] global stack overflow " | |
| 1020 "during parMark"); | |
| 1021 } | |
| 1022 } | |
| 1023 } | |
| 1024 } | |
| 1025 } | |
| 1026 | |
| 1027 class CMConcurrentMarkingTask: public AbstractGangTask { | |
| 1028 private: | |
| 1029 ConcurrentMark* _cm; | |
| 1030 ConcurrentMarkThread* _cmt; | |
| 1031 | |
| 1032 public: | |
| 1033 void work(int worker_i) { | |
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1034 assert(Thread::current()->is_ConcurrentGC_thread(), |
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1035 "this should only be done by a conc GC thread"); |
| 342 | 1036 |
| 1037 double start_vtime = os::elapsedVTime(); | |
| 1038 | |
| 1039 ConcurrentGCThread::stsJoin(); | |
| 1040 | |
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1041 assert((size_t) worker_i < _cm->active_tasks(), "invariant"); |
| 342 | 1042 CMTask* the_task = _cm->task(worker_i); |
| 1043 the_task->record_start_time(); | |
| 1044 if (!_cm->has_aborted()) { | |
| 1045 do { | |
| 1046 double start_vtime_sec = os::elapsedVTime(); | |
| 1047 double start_time_sec = os::elapsedTime(); | |
| 1048 the_task->do_marking_step(10.0); | |
| 1049 double end_time_sec = os::elapsedTime(); | |
| 1050 double end_vtime_sec = os::elapsedVTime(); | |
| 1051 double elapsed_vtime_sec = end_vtime_sec - start_vtime_sec; | |
| 1052 double elapsed_time_sec = end_time_sec - start_time_sec; | |
| 1053 _cm->clear_has_overflown(); | |
| 1054 | |
| 1055 bool ret = _cm->do_yield_check(worker_i); | |
| 1056 | |
| 1057 jlong sleep_time_ms; | |
| 1058 if (!_cm->has_aborted() && the_task->has_aborted()) { | |
| 1059 sleep_time_ms = | |
| 1060 (jlong) (elapsed_vtime_sec * _cm->sleep_factor() * 1000.0); | |
| 1061 ConcurrentGCThread::stsLeave(); | |
| 1062 os::sleep(Thread::current(), sleep_time_ms, false); | |
| 1063 ConcurrentGCThread::stsJoin(); | |
| 1064 } | |
| 1065 double end_time2_sec = os::elapsedTime(); | |
| 1066 double elapsed_time2_sec = end_time2_sec - start_time_sec; | |
| 1067 | |
| 1068 #if 0 | |
| 1069 gclog_or_tty->print_cr("CM: elapsed %1.4lf ms, sleep %1.4lf ms, " | |
| 1070 "overhead %1.4lf", | |
| 1071 elapsed_vtime_sec * 1000.0, (double) sleep_time_ms, | |
| 1072 the_task->conc_overhead(os::elapsedTime()) * 8.0); | |
| 1073 gclog_or_tty->print_cr("elapsed time %1.4lf ms, time 2: %1.4lf ms", | |
| 1074 elapsed_time_sec * 1000.0, elapsed_time2_sec * 1000.0); | |
| 1075 #endif | |
| 1076 } while (!_cm->has_aborted() && the_task->has_aborted()); | |
| 1077 } | |
| 1078 the_task->record_end_time(); | |
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1079 guarantee(!the_task->has_aborted() || _cm->has_aborted(), "invariant"); |
| 342 | 1080 |
| 1081 ConcurrentGCThread::stsLeave(); | |
| 1082 | |
| 1083 double end_vtime = os::elapsedVTime(); | |
| 1084 _cm->update_accum_task_vtime(worker_i, end_vtime - start_vtime); | |
| 1085 } | |
| 1086 | |
| 1087 CMConcurrentMarkingTask(ConcurrentMark* cm, | |
| 1088 ConcurrentMarkThread* cmt) : | |
| 1089 AbstractGangTask("Concurrent Mark"), _cm(cm), _cmt(cmt) { } | |
| 1090 | |
| 1091 ~CMConcurrentMarkingTask() { } | |
| 1092 }; | |
| 1093 | |
| 1094 void ConcurrentMark::markFromRoots() { | |
| 1095 // we might be tempted to assert that: | |
| 1096 // assert(asynch == !SafepointSynchronize::is_at_safepoint(), | |
| 1097 // "inconsistent argument?"); | |
| 1098 // However that wouldn't be right, because it's possible that | |
| 1099 // a safepoint is indeed in progress as a younger generation | |
| 1100 // stop-the-world GC happens even as we mark in this generation. | |
| 1101 | |
| 1102 _restart_for_overflow = false; | |
| 1103 | |
| 1104 set_phase(MAX2((size_t) 1, parallel_marking_threads()), true); | |
| 1105 | |
| 1106 CMConcurrentMarkingTask markingTask(this, cmThread()); | |
| 1107 if (parallel_marking_threads() > 0) | |
| 1108 _parallel_workers->run_task(&markingTask); | |
| 1109 else | |
| 1110 markingTask.work(0); | |
| 1111 print_stats(); | |
| 1112 } | |
| 1113 | |
| 1114 void ConcurrentMark::checkpointRootsFinal(bool clear_all_soft_refs) { | |
| 1115 // world is stopped at this checkpoint | |
| 1116 assert(SafepointSynchronize::is_at_safepoint(), | |
| 1117 "world should be stopped"); | |
| 1118 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1119 | |
| 1120 // If a full collection has happened, we shouldn't do this. | |
| 1121 if (has_aborted()) { | |
| 1122 g1h->set_marking_complete(); // So bitmap clearing isn't confused | |
| 1123 return; | |
| 1124 } | |
| 1125 | |
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1126 if (VerifyDuringGC) { |
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1127 HandleMark hm; // handle scope |
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1128 gclog_or_tty->print(" VerifyDuringGC:(before)"); |
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1129 Universe::heap()->prepare_for_verify(); |
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1130 Universe::verify(true, false, true); |
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1131 } |
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1132 |
| 342 | 1133 G1CollectorPolicy* g1p = g1h->g1_policy(); |
| 1134 g1p->record_concurrent_mark_remark_start(); | |
| 1135 | |
| 1136 double start = os::elapsedTime(); | |
| 1137 | |
| 1138 checkpointRootsFinalWork(); | |
| 1139 | |
| 1140 double mark_work_end = os::elapsedTime(); | |
| 1141 | |
| 1142 weakRefsWork(clear_all_soft_refs); | |
| 1143 | |
| 1144 if (has_overflown()) { | |
| 1145 // Oops. We overflowed. Restart concurrent marking. | |
| 1146 _restart_for_overflow = true; | |
| 1147 // Clear the flag. We do not need it any more. | |
| 1148 clear_has_overflown(); | |
| 1149 if (G1TraceMarkStackOverflow) | |
| 1150 gclog_or_tty->print_cr("\nRemark led to restart for overflow."); | |
| 1151 } else { | |
| 1152 // We're done with marking. | |
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1153 // This is the end of the marking cycle, we're expected all |
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1154 // threads to have SATB queues with active set to true. |
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1155 JavaThread::satb_mark_queue_set().set_active_all_threads( |
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1156 false, /* new active value */ |
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1157 true /* expected_active */); |
| 811 | 1158 |
| 1159 if (VerifyDuringGC) { | |
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1160 HandleMark hm; // handle scope |
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1161 gclog_or_tty->print(" VerifyDuringGC:(after)"); |
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1162 Universe::heap()->prepare_for_verify(); |
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1163 Universe::heap()->verify(/* allow_dirty */ true, |
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1164 /* silent */ false, |
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1165 /* use_prev_marking */ false); |
| 811 | 1166 } |
| 342 | 1167 } |
| 1168 | |
| 1169 #if VERIFY_OBJS_PROCESSED | |
| 1170 _scan_obj_cl.objs_processed = 0; | |
| 1171 ThreadLocalObjQueue::objs_enqueued = 0; | |
| 1172 #endif | |
| 1173 | |
| 1174 // Statistics | |
| 1175 double now = os::elapsedTime(); | |
| 1176 _remark_mark_times.add((mark_work_end - start) * 1000.0); | |
| 1177 _remark_weak_ref_times.add((now - mark_work_end) * 1000.0); | |
| 1178 _remark_times.add((now - start) * 1000.0); | |
| 1179 | |
| 1180 g1p->record_concurrent_mark_remark_end(); | |
| 1181 } | |
| 1182 | |
| 1183 | |
| 1184 #define CARD_BM_TEST_MODE 0 | |
| 1185 | |
| 1186 class CalcLiveObjectsClosure: public HeapRegionClosure { | |
| 1187 | |
| 1188 CMBitMapRO* _bm; | |
| 1189 ConcurrentMark* _cm; | |
| 1190 bool _changed; | |
| 1191 bool _yield; | |
| 1192 size_t _words_done; | |
| 1193 size_t _tot_live; | |
| 1194 size_t _tot_used; | |
| 1195 size_t _regions_done; | |
| 1196 double _start_vtime_sec; | |
| 1197 | |
| 1198 BitMap* _region_bm; | |
| 1199 BitMap* _card_bm; | |
| 1200 intptr_t _bottom_card_num; | |
| 1201 bool _final; | |
| 1202 | |
| 1203 void mark_card_num_range(intptr_t start_card_num, intptr_t last_card_num) { | |
| 1204 for (intptr_t i = start_card_num; i <= last_card_num; i++) { | |
| 1205 #if CARD_BM_TEST_MODE | |
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1206 guarantee(_card_bm->at(i - _bottom_card_num), "Should already be set."); |
| 342 | 1207 #else |
| 1208 _card_bm->par_at_put(i - _bottom_card_num, 1); | |
| 1209 #endif | |
| 1210 } | |
| 1211 } | |
| 1212 | |
| 1213 public: | |
| 1214 CalcLiveObjectsClosure(bool final, | |
| 1215 CMBitMapRO *bm, ConcurrentMark *cm, | |
| 936 | 1216 BitMap* region_bm, BitMap* card_bm) : |
| 342 | 1217 _bm(bm), _cm(cm), _changed(false), _yield(true), |
| 1218 _words_done(0), _tot_live(0), _tot_used(0), | |
| 936 | 1219 _region_bm(region_bm), _card_bm(card_bm),_final(final), |
| 342 | 1220 _regions_done(0), _start_vtime_sec(0.0) |
| 1221 { | |
| 1222 _bottom_card_num = | |
| 1223 intptr_t(uintptr_t(G1CollectedHeap::heap()->reserved_region().start()) >> | |
| 1224 CardTableModRefBS::card_shift); | |
| 1225 } | |
| 1226 | |
| 829 | 1227 // It takes a region that's not empty (i.e., it has at least one |
| 1228 // live object in it and sets its corresponding bit on the region | |
| 1229 // bitmap to 1. If the region is "starts humongous" it will also set | |
| 1230 // to 1 the bits on the region bitmap that correspond to its | |
| 1231 // associated "continues humongous" regions. | |
| 1232 void set_bit_for_region(HeapRegion* hr) { | |
| 1233 assert(!hr->continuesHumongous(), "should have filtered those out"); | |
| 1234 | |
| 1235 size_t index = hr->hrs_index(); | |
| 1236 if (!hr->startsHumongous()) { | |
| 1237 // Normal (non-humongous) case: just set the bit. | |
| 1238 _region_bm->par_at_put((BitMap::idx_t) index, true); | |
| 1239 } else { | |
| 1240 // Starts humongous case: calculate how many regions are part of | |
| 1241 // this humongous region and then set the bit range. It might | |
| 1242 // have been a bit more efficient to look at the object that | |
| 1243 // spans these humongous regions to calculate their number from | |
| 1244 // the object's size. However, it's a good idea to calculate | |
| 1245 // this based on the metadata itself, and not the region | |
| 1246 // contents, so that this code is not aware of what goes into | |
| 1247 // the humongous regions (in case this changes in the future). | |
| 1248 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1249 size_t end_index = index + 1; | |
| 831 | 1250 while (end_index < g1h->n_regions()) { |
| 1251 HeapRegion* chr = g1h->region_at(end_index); | |
| 829 | 1252 if (!chr->continuesHumongous()) { |
| 1253 break; | |
| 1254 } | |
| 1255 end_index += 1; | |
| 1256 } | |
| 1257 _region_bm->par_at_put_range((BitMap::idx_t) index, | |
| 1258 (BitMap::idx_t) end_index, true); | |
| 1259 } | |
| 1260 } | |
| 1261 | |
| 342 | 1262 bool doHeapRegion(HeapRegion* hr) { |
| 1263 if (!_final && _regions_done == 0) | |
| 1264 _start_vtime_sec = os::elapsedVTime(); | |
| 1265 | |
| 639 | 1266 if (hr->continuesHumongous()) { |
| 829 | 1267 // We will ignore these here and process them when their |
| 1268 // associated "starts humongous" region is processed (see | |
| 1269 // set_bit_for_heap_region()). Note that we cannot rely on their | |
| 1270 // associated "starts humongous" region to have their bit set to | |
| 1271 // 1 since, due to the region chunking in the parallel region | |
| 1272 // iteration, a "continues humongous" region might be visited | |
| 1273 // before its associated "starts humongous". | |
| 639 | 1274 return false; |
| 1275 } | |
| 342 | 1276 |
| 1277 HeapWord* nextTop = hr->next_top_at_mark_start(); | |
| 1278 HeapWord* start = hr->top_at_conc_mark_count(); | |
| 1279 assert(hr->bottom() <= start && start <= hr->end() && | |
| 1280 hr->bottom() <= nextTop && nextTop <= hr->end() && | |
| 1281 start <= nextTop, | |
| 1282 "Preconditions."); | |
| 1283 // Otherwise, record the number of word's we'll examine. | |
| 1284 size_t words_done = (nextTop - start); | |
| 1285 // Find the first marked object at or after "start". | |
| 1286 start = _bm->getNextMarkedWordAddress(start, nextTop); | |
| 1287 size_t marked_bytes = 0; | |
| 1288 | |
| 1289 // Below, the term "card num" means the result of shifting an address | |
| 1290 // by the card shift -- address 0 corresponds to card number 0. One | |
| 1291 // must subtract the card num of the bottom of the heap to obtain a | |
| 1292 // card table index. | |
| 1293 // The first card num of the sequence of live cards currently being | |
| 1294 // constructed. -1 ==> no sequence. | |
| 1295 intptr_t start_card_num = -1; | |
| 1296 // The last card num of the sequence of live cards currently being | |
| 1297 // constructed. -1 ==> no sequence. | |
| 1298 intptr_t last_card_num = -1; | |
| 1299 | |
| 1300 while (start < nextTop) { | |
| 1301 if (_yield && _cm->do_yield_check()) { | |
| 1302 // We yielded. It might be for a full collection, in which case | |
| 1303 // all bets are off; terminate the traversal. | |
| 1304 if (_cm->has_aborted()) { | |
| 1305 _changed = false; | |
| 1306 return true; | |
| 1307 } else { | |
| 1308 // Otherwise, it might be a collection pause, and the region | |
| 1309 // we're looking at might be in the collection set. We'll | |
| 1310 // abandon this region. | |
| 1311 return false; | |
| 1312 } | |
| 1313 } | |
| 1314 oop obj = oop(start); | |
| 1315 int obj_sz = obj->size(); | |
| 1316 // The card num of the start of the current object. | |
| 1317 intptr_t obj_card_num = | |
| 1318 intptr_t(uintptr_t(start) >> CardTableModRefBS::card_shift); | |
| 1319 | |
| 1320 HeapWord* obj_last = start + obj_sz - 1; | |
| 1321 intptr_t obj_last_card_num = | |
| 1322 intptr_t(uintptr_t(obj_last) >> CardTableModRefBS::card_shift); | |
| 1323 | |
| 1324 if (obj_card_num != last_card_num) { | |
| 1325 if (start_card_num == -1) { | |
| 1326 assert(last_card_num == -1, "Both or neither."); | |
| 1327 start_card_num = obj_card_num; | |
| 1328 } else { | |
| 1329 assert(last_card_num != -1, "Both or neither."); | |
| 1330 assert(obj_card_num >= last_card_num, "Inv"); | |
| 1331 if ((obj_card_num - last_card_num) > 1) { | |
| 1332 // Mark the last run, and start a new one. | |
| 1333 mark_card_num_range(start_card_num, last_card_num); | |
| 1334 start_card_num = obj_card_num; | |
| 1335 } | |
| 1336 } | |
| 1337 #if CARD_BM_TEST_MODE | |
| 1338 /* | |
| 1339 gclog_or_tty->print_cr("Setting bits from %d/%d.", | |
| 1340 obj_card_num - _bottom_card_num, | |
| 1341 obj_last_card_num - _bottom_card_num); | |
| 1342 */ | |
| 1343 for (intptr_t j = obj_card_num; j <= obj_last_card_num; j++) { | |
| 1344 _card_bm->par_at_put(j - _bottom_card_num, 1); | |
| 1345 } | |
| 1346 #endif | |
| 1347 } | |
| 1348 // In any case, we set the last card num. | |
| 1349 last_card_num = obj_last_card_num; | |
| 1350 | |
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1351 marked_bytes += (size_t)obj_sz * HeapWordSize; |
| 342 | 1352 // Find the next marked object after this one. |
| 1353 start = _bm->getNextMarkedWordAddress(start + 1, nextTop); | |
| 1354 _changed = true; | |
| 1355 } | |
| 1356 // Handle the last range, if any. | |
| 1357 if (start_card_num != -1) | |
| 1358 mark_card_num_range(start_card_num, last_card_num); | |
| 1359 if (_final) { | |
| 1360 // Mark the allocated-since-marking portion... | |
| 1361 HeapWord* tp = hr->top(); | |
| 1362 if (nextTop < tp) { | |
| 1363 start_card_num = | |
| 1364 intptr_t(uintptr_t(nextTop) >> CardTableModRefBS::card_shift); | |
| 1365 last_card_num = | |
| 1366 intptr_t(uintptr_t(tp) >> CardTableModRefBS::card_shift); | |
| 1367 mark_card_num_range(start_card_num, last_card_num); | |
| 1368 // This definitely means the region has live objects. | |
| 829 | 1369 set_bit_for_region(hr); |
| 342 | 1370 } |
| 1371 } | |
| 1372 | |
| 1373 hr->add_to_marked_bytes(marked_bytes); | |
| 1374 // Update the live region bitmap. | |
| 1375 if (marked_bytes > 0) { | |
| 829 | 1376 set_bit_for_region(hr); |
| 342 | 1377 } |
| 1378 hr->set_top_at_conc_mark_count(nextTop); | |
| 1379 _tot_live += hr->next_live_bytes(); | |
| 1380 _tot_used += hr->used(); | |
| 1381 _words_done = words_done; | |
| 1382 | |
| 1383 if (!_final) { | |
| 1384 ++_regions_done; | |
| 1385 if (_regions_done % 10 == 0) { | |
| 1386 double end_vtime_sec = os::elapsedVTime(); | |
| 1387 double elapsed_vtime_sec = end_vtime_sec - _start_vtime_sec; | |
| 1388 if (elapsed_vtime_sec > (10.0 / 1000.0)) { | |
| 1389 jlong sleep_time_ms = | |
| 1390 (jlong) (elapsed_vtime_sec * _cm->cleanup_sleep_factor() * 1000.0); | |
| 1391 os::sleep(Thread::current(), sleep_time_ms, false); | |
| 1392 _start_vtime_sec = end_vtime_sec; | |
| 1393 } | |
| 1394 } | |
| 1395 } | |
| 1396 | |
| 1397 return false; | |
| 1398 } | |
| 1399 | |
| 1400 bool changed() { return _changed; } | |
| 1401 void reset() { _changed = false; _words_done = 0; } | |
| 1402 void no_yield() { _yield = false; } | |
| 1403 size_t words_done() { return _words_done; } | |
| 1404 size_t tot_live() { return _tot_live; } | |
| 1405 size_t tot_used() { return _tot_used; } | |
| 1406 }; | |
| 1407 | |
| 1408 | |
| 1409 void ConcurrentMark::calcDesiredRegions() { | |
| 1410 _region_bm.clear(); | |
| 1411 _card_bm.clear(); | |
| 1412 CalcLiveObjectsClosure calccl(false /*final*/, | |
| 1413 nextMarkBitMap(), this, | |
| 936 | 1414 &_region_bm, &_card_bm); |
| 342 | 1415 G1CollectedHeap *g1h = G1CollectedHeap::heap(); |
| 1416 g1h->heap_region_iterate(&calccl); | |
| 1417 | |
| 1418 do { | |
| 1419 calccl.reset(); | |
| 1420 g1h->heap_region_iterate(&calccl); | |
| 1421 } while (calccl.changed()); | |
| 1422 } | |
| 1423 | |
| 1424 class G1ParFinalCountTask: public AbstractGangTask { | |
| 1425 protected: | |
| 1426 G1CollectedHeap* _g1h; | |
| 1427 CMBitMap* _bm; | |
| 1428 size_t _n_workers; | |
| 1429 size_t *_live_bytes; | |
| 1430 size_t *_used_bytes; | |
| 1431 BitMap* _region_bm; | |
| 1432 BitMap* _card_bm; | |
| 1433 public: | |
| 1434 G1ParFinalCountTask(G1CollectedHeap* g1h, CMBitMap* bm, | |
| 1435 BitMap* region_bm, BitMap* card_bm) : | |
| 1436 AbstractGangTask("G1 final counting"), _g1h(g1h), | |
| 1437 _bm(bm), _region_bm(region_bm), _card_bm(card_bm) | |
| 1438 { | |
| 1439 if (ParallelGCThreads > 0) | |
| 1440 _n_workers = _g1h->workers()->total_workers(); | |
| 1441 else | |
| 1442 _n_workers = 1; | |
| 1443 _live_bytes = NEW_C_HEAP_ARRAY(size_t, _n_workers); | |
| 1444 _used_bytes = NEW_C_HEAP_ARRAY(size_t, _n_workers); | |
| 1445 } | |
| 1446 | |
| 1447 ~G1ParFinalCountTask() { | |
| 1448 FREE_C_HEAP_ARRAY(size_t, _live_bytes); | |
| 1449 FREE_C_HEAP_ARRAY(size_t, _used_bytes); | |
| 1450 } | |
| 1451 | |
| 1452 void work(int i) { | |
| 1453 CalcLiveObjectsClosure calccl(true /*final*/, | |
| 1454 _bm, _g1h->concurrent_mark(), | |
| 936 | 1455 _region_bm, _card_bm); |
| 342 | 1456 calccl.no_yield(); |
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1457 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 355 | 1458 _g1h->heap_region_par_iterate_chunked(&calccl, i, |
| 1459 HeapRegion::FinalCountClaimValue); | |
| 342 | 1460 } else { |
| 1461 _g1h->heap_region_iterate(&calccl); | |
| 1462 } | |
| 1463 assert(calccl.complete(), "Shouldn't have yielded!"); | |
| 1464 | |
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1465 assert((size_t) i < _n_workers, "invariant"); |
| 342 | 1466 _live_bytes[i] = calccl.tot_live(); |
| 1467 _used_bytes[i] = calccl.tot_used(); | |
| 1468 } | |
| 1469 size_t live_bytes() { | |
| 1470 size_t live_bytes = 0; | |
| 1471 for (size_t i = 0; i < _n_workers; ++i) | |
| 1472 live_bytes += _live_bytes[i]; | |
| 1473 return live_bytes; | |
| 1474 } | |
| 1475 size_t used_bytes() { | |
| 1476 size_t used_bytes = 0; | |
| 1477 for (size_t i = 0; i < _n_workers; ++i) | |
| 1478 used_bytes += _used_bytes[i]; | |
| 1479 return used_bytes; | |
| 1480 } | |
| 1481 }; | |
| 1482 | |
| 1483 class G1ParNoteEndTask; | |
| 1484 | |
| 1485 class G1NoteEndOfConcMarkClosure : public HeapRegionClosure { | |
| 1486 G1CollectedHeap* _g1; | |
| 1487 int _worker_num; | |
| 1488 size_t _max_live_bytes; | |
| 1489 size_t _regions_claimed; | |
| 1490 size_t _freed_bytes; | |
| 1491 size_t _cleared_h_regions; | |
| 1492 size_t _freed_regions; | |
| 1493 UncleanRegionList* _unclean_region_list; | |
| 1494 double _claimed_region_time; | |
| 1495 double _max_region_time; | |
| 1496 | |
| 1497 public: | |
| 1498 G1NoteEndOfConcMarkClosure(G1CollectedHeap* g1, | |
| 1499 UncleanRegionList* list, | |
| 1500 int worker_num); | |
| 1501 size_t freed_bytes() { return _freed_bytes; } | |
| 1502 size_t cleared_h_regions() { return _cleared_h_regions; } | |
| 1503 size_t freed_regions() { return _freed_regions; } | |
| 1504 UncleanRegionList* unclean_region_list() { | |
| 1505 return _unclean_region_list; | |
| 1506 } | |
| 1507 | |
| 1508 bool doHeapRegion(HeapRegion *r); | |
| 1509 | |
| 1510 size_t max_live_bytes() { return _max_live_bytes; } | |
| 1511 size_t regions_claimed() { return _regions_claimed; } | |
| 1512 double claimed_region_time_sec() { return _claimed_region_time; } | |
| 1513 double max_region_time_sec() { return _max_region_time; } | |
| 1514 }; | |
| 1515 | |
| 1516 class G1ParNoteEndTask: public AbstractGangTask { | |
| 1517 friend class G1NoteEndOfConcMarkClosure; | |
| 1518 protected: | |
| 1519 G1CollectedHeap* _g1h; | |
| 1520 size_t _max_live_bytes; | |
| 1521 size_t _freed_bytes; | |
| 1522 ConcurrentMark::ParCleanupThreadState** _par_cleanup_thread_state; | |
| 1523 public: | |
| 1524 G1ParNoteEndTask(G1CollectedHeap* g1h, | |
| 1525 ConcurrentMark::ParCleanupThreadState** | |
| 1526 par_cleanup_thread_state) : | |
| 1527 AbstractGangTask("G1 note end"), _g1h(g1h), | |
| 1528 _max_live_bytes(0), _freed_bytes(0), | |
| 1529 _par_cleanup_thread_state(par_cleanup_thread_state) | |
| 1530 {} | |
| 1531 | |
| 1532 void work(int i) { | |
| 1533 double start = os::elapsedTime(); | |
| 1534 G1NoteEndOfConcMarkClosure g1_note_end(_g1h, | |
| 1535 &_par_cleanup_thread_state[i]->list, | |
| 1536 i); | |
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1537 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 355 | 1538 _g1h->heap_region_par_iterate_chunked(&g1_note_end, i, |
| 1539 HeapRegion::NoteEndClaimValue); | |
| 342 | 1540 } else { |
| 1541 _g1h->heap_region_iterate(&g1_note_end); | |
| 1542 } | |
| 1543 assert(g1_note_end.complete(), "Shouldn't have yielded!"); | |
| 1544 | |
| 1545 // Now finish up freeing the current thread's regions. | |
| 1546 _g1h->finish_free_region_work(g1_note_end.freed_bytes(), | |
| 1547 g1_note_end.cleared_h_regions(), | |
| 1548 0, NULL); | |
| 1549 { | |
| 1550 MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag); | |
| 1551 _max_live_bytes += g1_note_end.max_live_bytes(); | |
| 1552 _freed_bytes += g1_note_end.freed_bytes(); | |
| 1553 } | |
| 1554 double end = os::elapsedTime(); | |
| 1555 if (G1PrintParCleanupStats) { | |
| 1556 gclog_or_tty->print(" Worker thread %d [%8.3f..%8.3f = %8.3f ms] " | |
| 1557 "claimed %d regions (tot = %8.3f ms, max = %8.3f ms).\n", | |
| 1558 i, start, end, (end-start)*1000.0, | |
| 1559 g1_note_end.regions_claimed(), | |
| 1560 g1_note_end.claimed_region_time_sec()*1000.0, | |
| 1561 g1_note_end.max_region_time_sec()*1000.0); | |
| 1562 } | |
| 1563 } | |
| 1564 size_t max_live_bytes() { return _max_live_bytes; } | |
| 1565 size_t freed_bytes() { return _freed_bytes; } | |
| 1566 }; | |
| 1567 | |
| 1568 class G1ParScrubRemSetTask: public AbstractGangTask { | |
| 1569 protected: | |
| 1570 G1RemSet* _g1rs; | |
| 1571 BitMap* _region_bm; | |
| 1572 BitMap* _card_bm; | |
| 1573 public: | |
| 1574 G1ParScrubRemSetTask(G1CollectedHeap* g1h, | |
| 1575 BitMap* region_bm, BitMap* card_bm) : | |
| 1576 AbstractGangTask("G1 ScrubRS"), _g1rs(g1h->g1_rem_set()), | |
| 1577 _region_bm(region_bm), _card_bm(card_bm) | |
| 1578 {} | |
| 1579 | |
| 1580 void work(int i) { | |
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1581 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 355 | 1582 _g1rs->scrub_par(_region_bm, _card_bm, i, |
| 1583 HeapRegion::ScrubRemSetClaimValue); | |
| 342 | 1584 } else { |
| 1585 _g1rs->scrub(_region_bm, _card_bm); | |
| 1586 } | |
| 1587 } | |
| 1588 | |
| 1589 }; | |
| 1590 | |
| 1591 G1NoteEndOfConcMarkClosure:: | |
| 1592 G1NoteEndOfConcMarkClosure(G1CollectedHeap* g1, | |
| 1593 UncleanRegionList* list, | |
| 1594 int worker_num) | |
| 1595 : _g1(g1), _worker_num(worker_num), | |
| 1596 _max_live_bytes(0), _regions_claimed(0), | |
| 1597 _freed_bytes(0), _cleared_h_regions(0), _freed_regions(0), | |
| 1598 _claimed_region_time(0.0), _max_region_time(0.0), | |
| 1599 _unclean_region_list(list) | |
| 1600 {} | |
| 1601 | |
| 1602 bool G1NoteEndOfConcMarkClosure::doHeapRegion(HeapRegion *r) { | |
| 1603 // We use a claim value of zero here because all regions | |
| 1604 // were claimed with value 1 in the FinalCount task. | |
| 1605 r->reset_gc_time_stamp(); | |
| 1606 if (!r->continuesHumongous()) { | |
| 1607 double start = os::elapsedTime(); | |
| 1608 _regions_claimed++; | |
| 1609 r->note_end_of_marking(); | |
| 1610 _max_live_bytes += r->max_live_bytes(); | |
| 1611 _g1->free_region_if_totally_empty_work(r, | |
| 1612 _freed_bytes, | |
| 1613 _cleared_h_regions, | |
| 1614 _freed_regions, | |
| 1615 _unclean_region_list, | |
| 1616 true /*par*/); | |
| 1617 double region_time = (os::elapsedTime() - start); | |
| 1618 _claimed_region_time += region_time; | |
| 1619 if (region_time > _max_region_time) _max_region_time = region_time; | |
| 1620 } | |
| 1621 return false; | |
| 1622 } | |
| 1623 | |
| 1624 void ConcurrentMark::cleanup() { | |
| 1625 // world is stopped at this checkpoint | |
| 1626 assert(SafepointSynchronize::is_at_safepoint(), | |
| 1627 "world should be stopped"); | |
| 1628 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1629 | |
| 1630 // If a full collection has happened, we shouldn't do this. | |
| 1631 if (has_aborted()) { | |
| 1632 g1h->set_marking_complete(); // So bitmap clearing isn't confused | |
| 1633 return; | |
| 1634 } | |
| 1635 | |
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1636 if (VerifyDuringGC) { |
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1637 HandleMark hm; // handle scope |
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1638 gclog_or_tty->print(" VerifyDuringGC:(before)"); |
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1639 Universe::heap()->prepare_for_verify(); |
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1640 Universe::verify(/* allow dirty */ true, |
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1641 /* silent */ false, |
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1642 /* prev marking */ true); |
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1643 } |
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1644 |
| 342 | 1645 G1CollectorPolicy* g1p = G1CollectedHeap::heap()->g1_policy(); |
| 1646 g1p->record_concurrent_mark_cleanup_start(); | |
| 1647 | |
| 1648 double start = os::elapsedTime(); | |
| 1649 | |
| 1650 // Do counting once more with the world stopped for good measure. | |
| 1651 G1ParFinalCountTask g1_par_count_task(g1h, nextMarkBitMap(), | |
| 1652 &_region_bm, &_card_bm); | |
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1653 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 355 | 1654 assert(g1h->check_heap_region_claim_values( |
| 1655 HeapRegion::InitialClaimValue), | |
| 1656 "sanity check"); | |
| 1657 | |
| 342 | 1658 int n_workers = g1h->workers()->total_workers(); |
| 1659 g1h->set_par_threads(n_workers); | |
| 1660 g1h->workers()->run_task(&g1_par_count_task); | |
| 1661 g1h->set_par_threads(0); | |
| 355 | 1662 |
| 1663 assert(g1h->check_heap_region_claim_values( | |
| 1664 HeapRegion::FinalCountClaimValue), | |
| 1665 "sanity check"); | |
| 342 | 1666 } else { |
| 1667 g1_par_count_task.work(0); | |
| 1668 } | |
| 1669 | |
| 1670 size_t known_garbage_bytes = | |
| 1671 g1_par_count_task.used_bytes() - g1_par_count_task.live_bytes(); | |
| 1672 #if 0 | |
| 1673 gclog_or_tty->print_cr("used %1.2lf, live %1.2lf, garbage %1.2lf", | |
| 1674 (double) g1_par_count_task.used_bytes() / (double) (1024 * 1024), | |
| 1675 (double) g1_par_count_task.live_bytes() / (double) (1024 * 1024), | |
| 1676 (double) known_garbage_bytes / (double) (1024 * 1024)); | |
| 1677 #endif // 0 | |
| 1678 g1p->set_known_garbage_bytes(known_garbage_bytes); | |
| 1679 | |
| 1680 size_t start_used_bytes = g1h->used(); | |
| 1681 _at_least_one_mark_complete = true; | |
| 1682 g1h->set_marking_complete(); | |
| 1683 | |
| 1684 double count_end = os::elapsedTime(); | |
| 1685 double this_final_counting_time = (count_end - start); | |
| 1686 if (G1PrintParCleanupStats) { | |
| 1687 gclog_or_tty->print_cr("Cleanup:"); | |
| 1688 gclog_or_tty->print_cr(" Finalize counting: %8.3f ms", | |
| 1689 this_final_counting_time*1000.0); | |
| 1690 } | |
| 1691 _total_counting_time += this_final_counting_time; | |
| 1692 | |
| 1693 // Install newly created mark bitMap as "prev". | |
| 1694 swapMarkBitMaps(); | |
| 1695 | |
| 1696 g1h->reset_gc_time_stamp(); | |
| 1697 | |
| 1698 // Note end of marking in all heap regions. | |
| 1699 double note_end_start = os::elapsedTime(); | |
| 1700 G1ParNoteEndTask g1_par_note_end_task(g1h, _par_cleanup_thread_state); | |
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1701 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 342 | 1702 int n_workers = g1h->workers()->total_workers(); |
| 1703 g1h->set_par_threads(n_workers); | |
| 1704 g1h->workers()->run_task(&g1_par_note_end_task); | |
| 1705 g1h->set_par_threads(0); | |
| 355 | 1706 |
| 1707 assert(g1h->check_heap_region_claim_values(HeapRegion::NoteEndClaimValue), | |
| 1708 "sanity check"); | |
| 342 | 1709 } else { |
| 1710 g1_par_note_end_task.work(0); | |
| 1711 } | |
| 1712 g1h->set_unclean_regions_coming(true); | |
| 1713 double note_end_end = os::elapsedTime(); | |
| 1714 // Tell the mutators that there might be unclean regions coming... | |
| 1715 if (G1PrintParCleanupStats) { | |
| 1716 gclog_or_tty->print_cr(" note end of marking: %8.3f ms.", | |
| 1717 (note_end_end - note_end_start)*1000.0); | |
| 1718 } | |
| 1719 | |
| 355 | 1720 |
| 342 | 1721 // call below, since it affects the metric by which we sort the heap |
| 1722 // regions. | |
| 1723 if (G1ScrubRemSets) { | |
| 1724 double rs_scrub_start = os::elapsedTime(); | |
| 1725 G1ParScrubRemSetTask g1_par_scrub_rs_task(g1h, &_region_bm, &_card_bm); | |
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1726 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 342 | 1727 int n_workers = g1h->workers()->total_workers(); |
| 1728 g1h->set_par_threads(n_workers); | |
| 1729 g1h->workers()->run_task(&g1_par_scrub_rs_task); | |
| 1730 g1h->set_par_threads(0); | |
| 355 | 1731 |
| 1732 assert(g1h->check_heap_region_claim_values( | |
| 1733 HeapRegion::ScrubRemSetClaimValue), | |
| 1734 "sanity check"); | |
| 342 | 1735 } else { |
| 1736 g1_par_scrub_rs_task.work(0); | |
| 1737 } | |
| 1738 | |
| 1739 double rs_scrub_end = os::elapsedTime(); | |
| 1740 double this_rs_scrub_time = (rs_scrub_end - rs_scrub_start); | |
| 1741 _total_rs_scrub_time += this_rs_scrub_time; | |
| 1742 } | |
| 1743 | |
| 1744 // this will also free any regions totally full of garbage objects, | |
| 1745 // and sort the regions. | |
| 1746 g1h->g1_policy()->record_concurrent_mark_cleanup_end( | |
| 1747 g1_par_note_end_task.freed_bytes(), | |
| 1748 g1_par_note_end_task.max_live_bytes()); | |
| 1749 | |
| 1750 // Statistics. | |
| 1751 double end = os::elapsedTime(); | |
| 1752 _cleanup_times.add((end - start) * 1000.0); | |
| 1753 | |
| 1754 // G1CollectedHeap::heap()->print(); | |
| 1755 // gclog_or_tty->print_cr("HEAP GC TIME STAMP : %d", | |
| 1756 // G1CollectedHeap::heap()->get_gc_time_stamp()); | |
| 1757 | |
| 1758 if (PrintGC || PrintGCDetails) { | |
| 1759 g1h->print_size_transition(gclog_or_tty, | |
| 1760 start_used_bytes, | |
| 1761 g1h->used(), | |
| 1762 g1h->capacity()); | |
| 1763 } | |
| 1764 | |
| 1765 size_t cleaned_up_bytes = start_used_bytes - g1h->used(); | |
| 1766 g1p->decrease_known_garbage_bytes(cleaned_up_bytes); | |
| 1767 | |
| 1768 // We need to make this be a "collection" so any collection pause that | |
| 1769 // races with it goes around and waits for completeCleanup to finish. | |
| 1770 g1h->increment_total_collections(); | |
| 1771 | |
| 751 | 1772 if (VerifyDuringGC) { |
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1773 HandleMark hm; // handle scope |
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1774 gclog_or_tty->print(" VerifyDuringGC:(after)"); |
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1775 Universe::heap()->prepare_for_verify(); |
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1776 Universe::verify(/* allow dirty */ true, |
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1777 /* silent */ false, |
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1778 /* prev marking */ true); |
| 342 | 1779 } |
| 1780 } | |
| 1781 | |
| 1782 void ConcurrentMark::completeCleanup() { | |
| 1783 // A full collection intervened. | |
| 1784 if (has_aborted()) return; | |
| 1785 | |
| 1786 int first = 0; | |
| 1787 int last = (int)MAX2(ParallelGCThreads, (size_t)1); | |
| 1788 for (int t = 0; t < last; t++) { | |
| 1789 UncleanRegionList* list = &_par_cleanup_thread_state[t]->list; | |
| 1790 assert(list->well_formed(), "Inv"); | |
| 1791 HeapRegion* hd = list->hd(); | |
| 1792 while (hd != NULL) { | |
| 1793 // Now finish up the other stuff. | |
| 1794 hd->rem_set()->clear(); | |
| 1795 HeapRegion* next_hd = hd->next_from_unclean_list(); | |
| 1796 (void)list->pop(); | |
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1797 assert(list->hd() == next_hd, "how not?"); |
| 342 | 1798 _g1h->put_region_on_unclean_list(hd); |
| 1799 if (!hd->isHumongous()) { | |
| 1800 // Add this to the _free_regions count by 1. | |
| 1801 _g1h->finish_free_region_work(0, 0, 1, NULL); | |
| 1802 } | |
| 1803 hd = list->hd(); | |
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1804 assert(hd == next_hd, "how not?"); |
| 342 | 1805 } |
| 1806 } | |
| 1807 } | |
| 1808 | |
| 1809 | |
| 1810 class G1CMIsAliveClosure: public BoolObjectClosure { | |
| 1811 G1CollectedHeap* _g1; | |
| 1812 public: | |
| 1813 G1CMIsAliveClosure(G1CollectedHeap* g1) : | |
| 1814 _g1(g1) | |
| 1815 {} | |
| 1816 | |
| 1817 void do_object(oop obj) { | |
| 1818 assert(false, "not to be invoked"); | |
| 1819 } | |
| 1820 bool do_object_b(oop obj) { | |
| 1821 HeapWord* addr = (HeapWord*)obj; | |
| 1822 return addr != NULL && | |
| 1823 (!_g1->is_in_g1_reserved(addr) || !_g1->is_obj_ill(obj)); | |
| 1824 } | |
| 1825 }; | |
| 1826 | |
| 1827 class G1CMKeepAliveClosure: public OopClosure { | |
| 1828 G1CollectedHeap* _g1; | |
| 1829 ConcurrentMark* _cm; | |
| 1830 CMBitMap* _bitMap; | |
| 1831 public: | |
| 1832 G1CMKeepAliveClosure(G1CollectedHeap* g1, ConcurrentMark* cm, | |
| 1833 CMBitMap* bitMap) : | |
| 1834 _g1(g1), _cm(cm), | |
| 1835 _bitMap(bitMap) {} | |
| 1836 | |
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1837 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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1838 virtual void do_oop( oop* p) { do_oop_work(p); } |
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1839 |
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1840 template <class T> void do_oop_work(T* p) { |
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1841 oop thisOop = oopDesc::load_decode_heap_oop(p); |
| 342 | 1842 HeapWord* addr = (HeapWord*)thisOop; |
| 1843 if (_g1->is_in_g1_reserved(addr) && _g1->is_obj_ill(thisOop)) { | |
| 1844 _bitMap->mark(addr); | |
| 1845 _cm->mark_stack_push(thisOop); | |
| 1846 } | |
| 1847 } | |
| 1848 }; | |
| 1849 | |
| 1850 class G1CMDrainMarkingStackClosure: public VoidClosure { | |
| 1851 CMMarkStack* _markStack; | |
| 1852 CMBitMap* _bitMap; | |
| 1853 G1CMKeepAliveClosure* _oopClosure; | |
| 1854 public: | |
| 1855 G1CMDrainMarkingStackClosure(CMBitMap* bitMap, CMMarkStack* markStack, | |
| 1856 G1CMKeepAliveClosure* oopClosure) : | |
| 1857 _bitMap(bitMap), | |
| 1858 _markStack(markStack), | |
| 1859 _oopClosure(oopClosure) | |
| 1860 {} | |
| 1861 | |
| 1862 void do_void() { | |
| 1863 _markStack->drain((OopClosure*)_oopClosure, _bitMap, false); | |
| 1864 } | |
| 1865 }; | |
| 1866 | |
| 1867 void ConcurrentMark::weakRefsWork(bool clear_all_soft_refs) { | |
| 1868 ResourceMark rm; | |
| 1869 HandleMark hm; | |
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1870 G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
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1871 ReferenceProcessor* rp = g1h->ref_processor(); |
| 342 | 1872 |
| 1873 // Process weak references. | |
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1874 rp->setup_policy(clear_all_soft_refs); |
| 342 | 1875 assert(_markStack.isEmpty(), "mark stack should be empty"); |
| 1876 | |
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1877 G1CMIsAliveClosure g1IsAliveClosure (g1h); |
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1878 G1CMKeepAliveClosure g1KeepAliveClosure(g1h, this, nextMarkBitMap()); |
| 342 | 1879 G1CMDrainMarkingStackClosure |
| 1880 g1DrainMarkingStackClosure(nextMarkBitMap(), &_markStack, | |
| 1881 &g1KeepAliveClosure); | |
| 1882 | |
| 1883 // XXXYYY Also: copy the parallel ref processing code from CMS. | |
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1884 rp->process_discovered_references(&g1IsAliveClosure, |
| 342 | 1885 &g1KeepAliveClosure, |
| 1886 &g1DrainMarkingStackClosure, | |
| 1887 NULL); | |
| 1888 assert(_markStack.overflow() || _markStack.isEmpty(), | |
| 1889 "mark stack should be empty (unless it overflowed)"); | |
| 1890 if (_markStack.overflow()) { | |
| 1891 set_has_overflown(); | |
| 1892 } | |
| 1893 | |
| 1894 rp->enqueue_discovered_references(); | |
| 1895 rp->verify_no_references_recorded(); | |
| 1896 assert(!rp->discovery_enabled(), "should have been disabled"); | |
| 1897 | |
| 1898 // Now clean up stale oops in SymbolTable and StringTable | |
| 1899 SymbolTable::unlink(&g1IsAliveClosure); | |
| 1900 StringTable::unlink(&g1IsAliveClosure); | |
| 1901 } | |
| 1902 | |
| 1903 void ConcurrentMark::swapMarkBitMaps() { | |
| 1904 CMBitMapRO* temp = _prevMarkBitMap; | |
| 1905 _prevMarkBitMap = (CMBitMapRO*)_nextMarkBitMap; | |
| 1906 _nextMarkBitMap = (CMBitMap*) temp; | |
| 1907 } | |
| 1908 | |
| 1909 class CMRemarkTask: public AbstractGangTask { | |
| 1910 private: | |
| 1911 ConcurrentMark *_cm; | |
| 1912 | |
| 1913 public: | |
| 1914 void work(int worker_i) { | |
| 1915 // Since all available tasks are actually started, we should | |
| 1916 // only proceed if we're supposed to be actived. | |
| 1917 if ((size_t)worker_i < _cm->active_tasks()) { | |
| 1918 CMTask* task = _cm->task(worker_i); | |
| 1919 task->record_start_time(); | |
| 1920 do { | |
| 1921 task->do_marking_step(1000000000.0 /* something very large */); | |
| 1922 } while (task->has_aborted() && !_cm->has_overflown()); | |
| 1923 // If we overflow, then we do not want to restart. We instead | |
| 1924 // want to abort remark and do concurrent marking again. | |
| 1925 task->record_end_time(); | |
| 1926 } | |
| 1927 } | |
| 1928 | |
| 1929 CMRemarkTask(ConcurrentMark* cm) : | |
| 1930 AbstractGangTask("Par Remark"), _cm(cm) { } | |
| 1931 }; | |
| 1932 | |
| 1933 void ConcurrentMark::checkpointRootsFinalWork() { | |
| 1934 ResourceMark rm; | |
| 1935 HandleMark hm; | |
| 1936 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 1937 | |
| 1938 g1h->ensure_parsability(false); | |
| 1939 | |
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1940 if (G1CollectedHeap::use_parallel_gc_threads()) { |
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1941 G1CollectedHeap::StrongRootsScope srs(g1h); |
| 342 | 1942 // this is remark, so we'll use up all available threads |
| 1943 int active_workers = ParallelGCThreads; | |
| 1944 set_phase(active_workers, false); | |
| 1945 | |
| 1946 CMRemarkTask remarkTask(this); | |
| 1947 // We will start all available threads, even if we decide that the | |
| 1948 // active_workers will be fewer. The extra ones will just bail out | |
| 1949 // immediately. | |
| 1950 int n_workers = g1h->workers()->total_workers(); | |
| 1951 g1h->set_par_threads(n_workers); | |
| 1952 g1h->workers()->run_task(&remarkTask); | |
| 1953 g1h->set_par_threads(0); | |
| 1954 } else { | |
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1955 G1CollectedHeap::StrongRootsScope srs(g1h); |
| 342 | 1956 // this is remark, so we'll use up all available threads |
| 1957 int active_workers = 1; | |
| 1958 set_phase(active_workers, false); | |
| 1959 | |
| 1960 CMRemarkTask remarkTask(this); | |
| 1961 // We will start all available threads, even if we decide that the | |
| 1962 // active_workers will be fewer. The extra ones will just bail out | |
| 1963 // immediately. | |
| 1964 remarkTask.work(0); | |
| 1965 } | |
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1966 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); |
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1967 guarantee(satb_mq_set.completed_buffers_num() == 0, "invariant"); |
| 342 | 1968 |
| 1969 print_stats(); | |
| 1970 | |
| 1971 if (!restart_for_overflow()) | |
| 1972 set_non_marking_state(); | |
| 1973 | |
| 1974 #if VERIFY_OBJS_PROCESSED | |
| 1975 if (_scan_obj_cl.objs_processed != ThreadLocalObjQueue::objs_enqueued) { | |
| 1976 gclog_or_tty->print_cr("Processed = %d, enqueued = %d.", | |
| 1977 _scan_obj_cl.objs_processed, | |
| 1978 ThreadLocalObjQueue::objs_enqueued); | |
| 1979 guarantee(_scan_obj_cl.objs_processed == | |
| 1980 ThreadLocalObjQueue::objs_enqueued, | |
| 1981 "Different number of objs processed and enqueued."); | |
| 1982 } | |
| 1983 #endif | |
| 1984 } | |
| 1985 | |
| 1044 | 1986 #ifndef PRODUCT |
| 1987 | |
| 1388 | 1988 class PrintReachableOopClosure: public OopClosure { |
| 342 | 1989 private: |
| 1990 G1CollectedHeap* _g1h; | |
| 1991 CMBitMapRO* _bitmap; | |
| 1992 outputStream* _out; | |
| 1044 | 1993 bool _use_prev_marking; |
| 1388 | 1994 bool _all; |
| 342 | 1995 |
| 1996 public: | |
| 1388 | 1997 PrintReachableOopClosure(CMBitMapRO* bitmap, |
| 1998 outputStream* out, | |
| 1999 bool use_prev_marking, | |
| 2000 bool all) : | |
| 1044 | 2001 _g1h(G1CollectedHeap::heap()), |
| 1388 | 2002 _bitmap(bitmap), _out(out), _use_prev_marking(use_prev_marking), _all(all) { } |
| 342 | 2003 |
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2004 void do_oop(narrowOop* p) { do_oop_work(p); } |
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2005 void do_oop( oop* p) { do_oop_work(p); } |
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2006 |
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2007 template <class T> void do_oop_work(T* p) { |
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2008 oop obj = oopDesc::load_decode_heap_oop(p); |
| 342 | 2009 const char* str = NULL; |
| 2010 const char* str2 = ""; | |
| 2011 | |
| 1388 | 2012 if (obj == NULL) { |
| 2013 str = ""; | |
| 2014 } else if (!_g1h->is_in_g1_reserved(obj)) { | |
| 2015 str = " O"; | |
| 2016 } else { | |
| 342 | 2017 HeapRegion* hr = _g1h->heap_region_containing(obj); |
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2018 guarantee(hr != NULL, "invariant"); |
| 1044 | 2019 bool over_tams = false; |
| 2020 if (_use_prev_marking) { | |
| 2021 over_tams = hr->obj_allocated_since_prev_marking(obj); | |
| 2022 } else { | |
| 2023 over_tams = hr->obj_allocated_since_next_marking(obj); | |
| 2024 } | |
| 1388 | 2025 bool marked = _bitmap->isMarked((HeapWord*) obj); |
| 1044 | 2026 |
| 2027 if (over_tams) { | |
| 1388 | 2028 str = " >"; |
| 2029 if (marked) { | |
| 342 | 2030 str2 = " AND MARKED"; |
| 1044 | 2031 } |
| 1388 | 2032 } else if (marked) { |
| 2033 str = " M"; | |
| 1044 | 2034 } else { |
| 1388 | 2035 str = " NOT"; |
| 1044 | 2036 } |
| 342 | 2037 } |
| 2038 | |
| 1388 | 2039 _out->print_cr(" "PTR_FORMAT": "PTR_FORMAT"%s%s", |
| 342 | 2040 p, (void*) obj, str, str2); |
| 2041 } | |
| 2042 }; | |
| 2043 | |
| 1388 | 2044 class PrintReachableObjectClosure : public ObjectClosure { |
| 342 | 2045 private: |
| 1044 | 2046 CMBitMapRO* _bitmap; |
| 342 | 2047 outputStream* _out; |
| 1044 | 2048 bool _use_prev_marking; |
| 1388 | 2049 bool _all; |
| 2050 HeapRegion* _hr; | |
| 342 | 2051 |
| 2052 public: | |
| 1388 | 2053 PrintReachableObjectClosure(CMBitMapRO* bitmap, |
| 2054 outputStream* out, | |
| 2055 bool use_prev_marking, | |
| 2056 bool all, | |
| 2057 HeapRegion* hr) : | |
| 2058 _bitmap(bitmap), _out(out), | |
| 2059 _use_prev_marking(use_prev_marking), _all(all), _hr(hr) { } | |
| 2060 | |
| 2061 void do_object(oop o) { | |
| 2062 bool over_tams; | |
| 2063 if (_use_prev_marking) { | |
| 2064 over_tams = _hr->obj_allocated_since_prev_marking(o); | |
| 2065 } else { | |
| 2066 over_tams = _hr->obj_allocated_since_next_marking(o); | |
| 2067 } | |
| 2068 bool marked = _bitmap->isMarked((HeapWord*) o); | |
| 2069 bool print_it = _all || over_tams || marked; | |
| 2070 | |
| 2071 if (print_it) { | |
| 2072 _out->print_cr(" "PTR_FORMAT"%s", | |
| 2073 o, (over_tams) ? " >" : (marked) ? " M" : ""); | |
| 2074 PrintReachableOopClosure oopCl(_bitmap, _out, _use_prev_marking, _all); | |
| 2075 o->oop_iterate(&oopCl); | |
| 2076 } | |
| 342 | 2077 } |
| 2078 }; | |
| 2079 | |
| 1388 | 2080 class PrintReachableRegionClosure : public HeapRegionClosure { |
| 342 | 2081 private: |
| 1044 | 2082 CMBitMapRO* _bitmap; |
| 342 | 2083 outputStream* _out; |
| 1044 | 2084 bool _use_prev_marking; |
| 1388 | 2085 bool _all; |
| 342 | 2086 |
| 2087 public: | |
| 2088 bool doHeapRegion(HeapRegion* hr) { | |
| 2089 HeapWord* b = hr->bottom(); | |
| 2090 HeapWord* e = hr->end(); | |
| 2091 HeapWord* t = hr->top(); | |
| 1044 | 2092 HeapWord* p = NULL; |
| 2093 if (_use_prev_marking) { | |
| 2094 p = hr->prev_top_at_mark_start(); | |
| 2095 } else { | |
| 2096 p = hr->next_top_at_mark_start(); | |
| 2097 } | |
| 342 | 2098 _out->print_cr("** ["PTR_FORMAT", "PTR_FORMAT"] top: "PTR_FORMAT" " |
| 1044 | 2099 "TAMS: "PTR_FORMAT, b, e, t, p); |
| 1388 | 2100 _out->cr(); |
| 2101 | |
| 2102 HeapWord* from = b; | |
| 2103 HeapWord* to = t; | |
| 2104 | |
| 2105 if (to > from) { | |
| 2106 _out->print_cr("Objects in ["PTR_FORMAT", "PTR_FORMAT"]", from, to); | |
| 2107 _out->cr(); | |
| 2108 PrintReachableObjectClosure ocl(_bitmap, _out, | |
| 2109 _use_prev_marking, _all, hr); | |
| 2110 hr->object_iterate_mem_careful(MemRegion(from, to), &ocl); | |
| 2111 _out->cr(); | |
| 2112 } | |
| 342 | 2113 |
| 2114 return false; | |
| 2115 } | |
| 2116 | |
| 1388 | 2117 PrintReachableRegionClosure(CMBitMapRO* bitmap, |
| 2118 outputStream* out, | |
| 2119 bool use_prev_marking, | |
| 2120 bool all) : | |
| 2121 _bitmap(bitmap), _out(out), _use_prev_marking(use_prev_marking), _all(all) { } | |
| 342 | 2122 }; |
| 2123 | |
| 1388 | 2124 void ConcurrentMark::print_reachable(const char* str, |
| 2125 bool use_prev_marking, | |
| 2126 bool all) { | |
| 2127 gclog_or_tty->cr(); | |
| 2128 gclog_or_tty->print_cr("== Doing heap dump... "); | |
| 1044 | 2129 |
| 2130 if (G1PrintReachableBaseFile == NULL) { | |
| 2131 gclog_or_tty->print_cr(" #### error: no base file defined"); | |
| 2132 return; | |
| 2133 } | |
| 2134 | |
| 2135 if (strlen(G1PrintReachableBaseFile) + 1 + strlen(str) > | |
| 2136 (JVM_MAXPATHLEN - 1)) { | |
| 2137 gclog_or_tty->print_cr(" #### error: file name too long"); | |
| 2138 return; | |
| 2139 } | |
| 2140 | |
| 2141 char file_name[JVM_MAXPATHLEN]; | |
| 2142 sprintf(file_name, "%s.%s", G1PrintReachableBaseFile, str); | |
| 2143 gclog_or_tty->print_cr(" dumping to file %s", file_name); | |
| 2144 | |
| 2145 fileStream fout(file_name); | |
| 2146 if (!fout.is_open()) { | |
| 2147 gclog_or_tty->print_cr(" #### error: could not open file"); | |
| 2148 return; | |
| 2149 } | |
| 2150 | |
| 2151 outputStream* out = &fout; | |
| 2152 | |
| 2153 CMBitMapRO* bitmap = NULL; | |
| 2154 if (use_prev_marking) { | |
| 2155 bitmap = _prevMarkBitMap; | |
| 2156 } else { | |
| 2157 bitmap = _nextMarkBitMap; | |
| 2158 } | |
| 2159 | |
| 2160 out->print_cr("-- USING %s", (use_prev_marking) ? "PTAMS" : "NTAMS"); | |
| 2161 out->cr(); | |
| 2162 | |
| 1388 | 2163 out->print_cr("--- ITERATING OVER REGIONS"); |
| 1044 | 2164 out->cr(); |
| 1388 | 2165 PrintReachableRegionClosure rcl(bitmap, out, use_prev_marking, all); |
| 2166 _g1h->heap_region_iterate(&rcl); | |
| 1044 | 2167 out->cr(); |
| 2168 | |
| 2169 gclog_or_tty->print_cr(" done"); | |
| 1388 | 2170 gclog_or_tty->flush(); |
| 342 | 2171 } |
| 2172 | |
| 1044 | 2173 #endif // PRODUCT |
| 2174 | |
| 342 | 2175 // This note is for drainAllSATBBuffers and the code in between. |
| 2176 // In the future we could reuse a task to do this work during an | |
| 2177 // evacuation pause (since now tasks are not active and can be claimed | |
| 2178 // during an evacuation pause). This was a late change to the code and | |
| 2179 // is currently not being taken advantage of. | |
| 2180 | |
| 2181 class CMGlobalObjectClosure : public ObjectClosure { | |
| 2182 private: | |
| 2183 ConcurrentMark* _cm; | |
| 2184 | |
| 2185 public: | |
| 2186 void do_object(oop obj) { | |
| 2187 _cm->deal_with_reference(obj); | |
| 2188 } | |
| 2189 | |
| 2190 CMGlobalObjectClosure(ConcurrentMark* cm) : _cm(cm) { } | |
| 2191 }; | |
| 2192 | |
| 2193 void ConcurrentMark::deal_with_reference(oop obj) { | |
| 2194 if (verbose_high()) | |
| 2195 gclog_or_tty->print_cr("[global] we're dealing with reference "PTR_FORMAT, | |
| 2196 (void*) obj); | |
| 2197 | |
| 2198 | |
| 2199 HeapWord* objAddr = (HeapWord*) obj; | |
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2200 assert(obj->is_oop_or_null(true /* ignore mark word */), "Error"); |
| 342 | 2201 if (_g1h->is_in_g1_reserved(objAddr)) { |
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2202 assert(obj != NULL, "is_in_g1_reserved should ensure this"); |
| 342 | 2203 HeapRegion* hr = _g1h->heap_region_containing(obj); |
| 2204 if (_g1h->is_obj_ill(obj, hr)) { | |
| 2205 if (verbose_high()) | |
| 2206 gclog_or_tty->print_cr("[global] "PTR_FORMAT" is not considered " | |
| 2207 "marked", (void*) obj); | |
| 2208 | |
| 2209 // we need to mark it first | |
| 2210 if (_nextMarkBitMap->parMark(objAddr)) { | |
| 2211 // No OrderAccess:store_load() is needed. It is implicit in the | |
| 2212 // CAS done in parMark(objAddr) above | |
| 2213 HeapWord* finger = _finger; | |
| 2214 if (objAddr < finger) { | |
| 2215 if (verbose_high()) | |
| 2216 gclog_or_tty->print_cr("[global] below the global finger " | |
| 2217 "("PTR_FORMAT"), pushing it", finger); | |
| 2218 if (!mark_stack_push(obj)) { | |
| 2219 if (verbose_low()) | |
| 2220 gclog_or_tty->print_cr("[global] global stack overflow during " | |
| 2221 "deal_with_reference"); | |
| 2222 } | |
| 2223 } | |
| 2224 } | |
| 2225 } | |
| 2226 } | |
| 2227 } | |
| 2228 | |
| 2229 void ConcurrentMark::drainAllSATBBuffers() { | |
| 2230 CMGlobalObjectClosure oc(this); | |
| 2231 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 2232 satb_mq_set.set_closure(&oc); | |
| 2233 | |
| 2234 while (satb_mq_set.apply_closure_to_completed_buffer()) { | |
| 2235 if (verbose_medium()) | |
| 2236 gclog_or_tty->print_cr("[global] processed an SATB buffer"); | |
| 2237 } | |
| 2238 | |
| 2239 // no need to check whether we should do this, as this is only | |
| 2240 // called during an evacuation pause | |
| 2241 satb_mq_set.iterate_closure_all_threads(); | |
| 2242 | |
| 2243 satb_mq_set.set_closure(NULL); | |
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2244 assert(satb_mq_set.completed_buffers_num() == 0, "invariant"); |
| 342 | 2245 } |
| 2246 | |
| 2247 void ConcurrentMark::markPrev(oop p) { | |
| 2248 // Note we are overriding the read-only view of the prev map here, via | |
| 2249 // the cast. | |
| 2250 ((CMBitMap*)_prevMarkBitMap)->mark((HeapWord*)p); | |
| 2251 } | |
| 2252 | |
| 2253 void ConcurrentMark::clear(oop p) { | |
| 2254 assert(p != NULL && p->is_oop(), "expected an oop"); | |
| 2255 HeapWord* addr = (HeapWord*)p; | |
| 2256 assert(addr >= _nextMarkBitMap->startWord() || | |
| 2257 addr < _nextMarkBitMap->endWord(), "in a region"); | |
| 2258 | |
| 2259 _nextMarkBitMap->clear(addr); | |
| 2260 } | |
| 2261 | |
| 2262 void ConcurrentMark::clearRangeBothMaps(MemRegion mr) { | |
| 2263 // Note we are overriding the read-only view of the prev map here, via | |
| 2264 // the cast. | |
| 2265 ((CMBitMap*)_prevMarkBitMap)->clearRange(mr); | |
| 2266 _nextMarkBitMap->clearRange(mr); | |
| 2267 } | |
| 2268 | |
| 2269 HeapRegion* | |
| 2270 ConcurrentMark::claim_region(int task_num) { | |
| 2271 // "checkpoint" the finger | |
| 2272 HeapWord* finger = _finger; | |
| 2273 | |
| 2274 // _heap_end will not change underneath our feet; it only changes at | |
| 2275 // yield points. | |
| 2276 while (finger < _heap_end) { | |
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2277 assert(_g1h->is_in_g1_reserved(finger), "invariant"); |
| 342 | 2278 |
| 2279 // is the gap between reading the finger and doing the CAS too long? | |
| 2280 | |
| 2281 HeapRegion* curr_region = _g1h->heap_region_containing(finger); | |
| 2282 HeapWord* bottom = curr_region->bottom(); | |
| 2283 HeapWord* end = curr_region->end(); | |
| 2284 HeapWord* limit = curr_region->next_top_at_mark_start(); | |
| 2285 | |
| 2286 if (verbose_low()) | |
| 2287 gclog_or_tty->print_cr("[%d] curr_region = "PTR_FORMAT" " | |
| 2288 "["PTR_FORMAT", "PTR_FORMAT"), " | |
| 2289 "limit = "PTR_FORMAT, | |
| 2290 task_num, curr_region, bottom, end, limit); | |
| 2291 | |
| 2292 HeapWord* res = | |
| 2293 (HeapWord*) Atomic::cmpxchg_ptr(end, &_finger, finger); | |
| 2294 if (res == finger) { | |
| 2295 // we succeeded | |
| 2296 | |
| 2297 // notice that _finger == end cannot be guaranteed here since, | |
| 2298 // someone else might have moved the finger even further | |
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2299 assert(_finger >= end, "the finger should have moved forward"); |
| 342 | 2300 |
| 2301 if (verbose_low()) | |
| 2302 gclog_or_tty->print_cr("[%d] we were successful with region = " | |
| 2303 PTR_FORMAT, task_num, curr_region); | |
| 2304 | |
| 2305 if (limit > bottom) { | |
| 2306 if (verbose_low()) | |
| 2307 gclog_or_tty->print_cr("[%d] region "PTR_FORMAT" is not empty, " | |
| 2308 "returning it ", task_num, curr_region); | |
| 2309 return curr_region; | |
| 2310 } else { | |
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2311 assert(limit == bottom, |
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2312 "the region limit should be at bottom"); |
| 342 | 2313 if (verbose_low()) |
| 2314 gclog_or_tty->print_cr("[%d] region "PTR_FORMAT" is empty, " | |
| 2315 "returning NULL", task_num, curr_region); | |
| 2316 // we return NULL and the caller should try calling | |
| 2317 // claim_region() again. | |
| 2318 return NULL; | |
| 2319 } | |
| 2320 } else { | |
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2321 assert(_finger > finger, "the finger should have moved forward"); |
| 342 | 2322 if (verbose_low()) |
| 2323 gclog_or_tty->print_cr("[%d] somebody else moved the finger, " | |
| 2324 "global finger = "PTR_FORMAT", " | |
| 2325 "our finger = "PTR_FORMAT, | |
| 2326 task_num, _finger, finger); | |
| 2327 | |
| 2328 // read it again | |
| 2329 finger = _finger; | |
| 2330 } | |
| 2331 } | |
| 2332 | |
| 2333 return NULL; | |
| 2334 } | |
| 2335 | |
| 2336 void ConcurrentMark::oops_do(OopClosure* cl) { | |
| 2337 if (_markStack.size() > 0 && verbose_low()) | |
| 2338 gclog_or_tty->print_cr("[global] scanning the global marking stack, " | |
| 2339 "size = %d", _markStack.size()); | |
| 2340 // we first iterate over the contents of the mark stack... | |
| 2341 _markStack.oops_do(cl); | |
| 2342 | |
| 2343 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 2344 OopTaskQueue* queue = _task_queues->queue((int)i); | |
| 2345 | |
| 2346 if (queue->size() > 0 && verbose_low()) | |
| 2347 gclog_or_tty->print_cr("[global] scanning task queue of task %d, " | |
| 2348 "size = %d", i, queue->size()); | |
| 2349 | |
| 2350 // ...then over the contents of the all the task queues. | |
| 2351 queue->oops_do(cl); | |
| 2352 } | |
| 2353 | |
| 2354 // finally, invalidate any entries that in the region stack that | |
| 2355 // point into the collection set | |
| 2356 if (_regionStack.invalidate_entries_into_cset()) { | |
| 2357 // otherwise, any gray objects copied during the evacuation pause | |
| 2358 // might not be visited. | |
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2359 assert(_should_gray_objects, "invariant"); |
| 342 | 2360 } |
| 2361 } | |
| 2362 | |
| 2363 void ConcurrentMark::clear_marking_state() { | |
| 2364 _markStack.setEmpty(); | |
| 2365 _markStack.clear_overflow(); | |
| 2366 _regionStack.setEmpty(); | |
| 2367 _regionStack.clear_overflow(); | |
| 2368 clear_has_overflown(); | |
| 2369 _finger = _heap_start; | |
| 2370 | |
| 2371 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 2372 OopTaskQueue* queue = _task_queues->queue(i); | |
| 2373 queue->set_empty(); | |
| 2374 } | |
| 2375 } | |
| 2376 | |
| 2377 void ConcurrentMark::print_stats() { | |
| 2378 if (verbose_stats()) { | |
| 2379 gclog_or_tty->print_cr("---------------------------------------------------------------------"); | |
| 2380 for (size_t i = 0; i < _active_tasks; ++i) { | |
| 2381 _tasks[i]->print_stats(); | |
| 2382 gclog_or_tty->print_cr("---------------------------------------------------------------------"); | |
| 2383 } | |
| 2384 } | |
| 2385 } | |
| 2386 | |
| 2387 class CSMarkOopClosure: public OopClosure { | |
| 2388 friend class CSMarkBitMapClosure; | |
| 2389 | |
| 2390 G1CollectedHeap* _g1h; | |
| 2391 CMBitMap* _bm; | |
| 2392 ConcurrentMark* _cm; | |
| 2393 oop* _ms; | |
| 2394 jint* _array_ind_stack; | |
| 2395 int _ms_size; | |
| 2396 int _ms_ind; | |
| 2397 int _array_increment; | |
| 2398 | |
| 2399 bool push(oop obj, int arr_ind = 0) { | |
| 2400 if (_ms_ind == _ms_size) { | |
| 2401 gclog_or_tty->print_cr("Mark stack is full."); | |
| 2402 return false; | |
| 2403 } | |
| 2404 _ms[_ms_ind] = obj; | |
| 2405 if (obj->is_objArray()) _array_ind_stack[_ms_ind] = arr_ind; | |
| 2406 _ms_ind++; | |
| 2407 return true; | |
| 2408 } | |
| 2409 | |
| 2410 oop pop() { | |
| 2411 if (_ms_ind == 0) return NULL; | |
| 2412 else { | |
| 2413 _ms_ind--; | |
| 2414 return _ms[_ms_ind]; | |
| 2415 } | |
| 2416 } | |
| 2417 | |
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2418 template <class T> bool drain() { |
| 342 | 2419 while (_ms_ind > 0) { |
| 2420 oop obj = pop(); | |
| 2421 assert(obj != NULL, "Since index was non-zero."); | |
| 2422 if (obj->is_objArray()) { | |
| 2423 jint arr_ind = _array_ind_stack[_ms_ind]; | |
| 2424 objArrayOop aobj = objArrayOop(obj); | |
| 2425 jint len = aobj->length(); | |
| 2426 jint next_arr_ind = arr_ind + _array_increment; | |
| 2427 if (next_arr_ind < len) { | |
| 2428 push(obj, next_arr_ind); | |
| 2429 } | |
| 2430 // Now process this portion of this one. | |
| 2431 int lim = MIN2(next_arr_ind, len); | |
| 2432 for (int j = arr_ind; j < lim; j++) { | |
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2433 do_oop(aobj->objArrayOopDesc::obj_at_addr<T>(j)); |
| 342 | 2434 } |
| 2435 | |
| 2436 } else { | |
| 2437 obj->oop_iterate(this); | |
| 2438 } | |
| 2439 if (abort()) return false; | |
| 2440 } | |
| 2441 return true; | |
| 2442 } | |
| 2443 | |
| 2444 public: | |
| 2445 CSMarkOopClosure(ConcurrentMark* cm, int ms_size) : | |
| 2446 _g1h(G1CollectedHeap::heap()), | |
| 2447 _cm(cm), | |
| 2448 _bm(cm->nextMarkBitMap()), | |
| 2449 _ms_size(ms_size), _ms_ind(0), | |
| 2450 _ms(NEW_C_HEAP_ARRAY(oop, ms_size)), | |
| 2451 _array_ind_stack(NEW_C_HEAP_ARRAY(jint, ms_size)), | |
| 2452 _array_increment(MAX2(ms_size/8, 16)) | |
| 2453 {} | |
| 2454 | |
| 2455 ~CSMarkOopClosure() { | |
| 2456 FREE_C_HEAP_ARRAY(oop, _ms); | |
| 2457 FREE_C_HEAP_ARRAY(jint, _array_ind_stack); | |
| 2458 } | |
| 2459 | |
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2460 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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2461 virtual void do_oop( oop* p) { do_oop_work(p); } |
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2462 |
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2463 template <class T> void do_oop_work(T* p) { |
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2464 T heap_oop = oopDesc::load_heap_oop(p); |
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2465 if (oopDesc::is_null(heap_oop)) return; |
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2466 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); |
| 342 | 2467 if (obj->is_forwarded()) { |
| 2468 // If the object has already been forwarded, we have to make sure | |
| 2469 // that it's marked. So follow the forwarding pointer. Note that | |
| 2470 // this does the right thing for self-forwarding pointers in the | |
| 2471 // evacuation failure case. | |
| 2472 obj = obj->forwardee(); | |
| 2473 } | |
| 2474 HeapRegion* hr = _g1h->heap_region_containing(obj); | |
| 2475 if (hr != NULL) { | |
| 2476 if (hr->in_collection_set()) { | |
| 2477 if (_g1h->is_obj_ill(obj)) { | |
| 2478 _bm->mark((HeapWord*)obj); | |
| 2479 if (!push(obj)) { | |
| 2480 gclog_or_tty->print_cr("Setting abort in CSMarkOopClosure because push failed."); | |
| 2481 set_abort(); | |
| 2482 } | |
| 2483 } | |
| 2484 } else { | |
| 2485 // Outside the collection set; we need to gray it | |
| 2486 _cm->deal_with_reference(obj); | |
| 2487 } | |
| 2488 } | |
| 2489 } | |
| 2490 }; | |
| 2491 | |
| 2492 class CSMarkBitMapClosure: public BitMapClosure { | |
| 2493 G1CollectedHeap* _g1h; | |
| 2494 CMBitMap* _bitMap; | |
| 2495 ConcurrentMark* _cm; | |
| 2496 CSMarkOopClosure _oop_cl; | |
| 2497 public: | |
| 2498 CSMarkBitMapClosure(ConcurrentMark* cm, int ms_size) : | |
| 2499 _g1h(G1CollectedHeap::heap()), | |
| 2500 _bitMap(cm->nextMarkBitMap()), | |
| 2501 _oop_cl(cm, ms_size) | |
| 2502 {} | |
| 2503 | |
| 2504 ~CSMarkBitMapClosure() {} | |
| 2505 | |
| 2506 bool do_bit(size_t offset) { | |
| 2507 // convert offset into a HeapWord* | |
| 2508 HeapWord* addr = _bitMap->offsetToHeapWord(offset); | |
| 2509 assert(_bitMap->endWord() && addr < _bitMap->endWord(), | |
| 2510 "address out of range"); | |
| 2511 assert(_bitMap->isMarked(addr), "tautology"); | |
| 2512 oop obj = oop(addr); | |
| 2513 if (!obj->is_forwarded()) { | |
| 2514 if (!_oop_cl.push(obj)) return false; | |
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2515 if (UseCompressedOops) { |
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2516 if (!_oop_cl.drain<narrowOop>()) return false; |
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2517 } else { |
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2518 if (!_oop_cl.drain<oop>()) return false; |
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2519 } |
| 342 | 2520 } |
| 2521 // Otherwise... | |
| 2522 return true; | |
| 2523 } | |
| 2524 }; | |
| 2525 | |
| 2526 | |
| 2527 class CompleteMarkingInCSHRClosure: public HeapRegionClosure { | |
| 2528 CMBitMap* _bm; | |
| 2529 CSMarkBitMapClosure _bit_cl; | |
| 2530 enum SomePrivateConstants { | |
| 2531 MSSize = 1000 | |
| 2532 }; | |
| 2533 bool _completed; | |
| 2534 public: | |
| 2535 CompleteMarkingInCSHRClosure(ConcurrentMark* cm) : | |
| 2536 _bm(cm->nextMarkBitMap()), | |
| 2537 _bit_cl(cm, MSSize), | |
| 2538 _completed(true) | |
| 2539 {} | |
| 2540 | |
| 2541 ~CompleteMarkingInCSHRClosure() {} | |
| 2542 | |
| 2543 bool doHeapRegion(HeapRegion* r) { | |
| 2544 if (!r->evacuation_failed()) { | |
| 2545 MemRegion mr = MemRegion(r->bottom(), r->next_top_at_mark_start()); | |
| 2546 if (!mr.is_empty()) { | |
| 2547 if (!_bm->iterate(&_bit_cl, mr)) { | |
| 2548 _completed = false; | |
| 2549 return true; | |
| 2550 } | |
| 2551 } | |
| 2552 } | |
| 2553 return false; | |
| 2554 } | |
| 2555 | |
| 2556 bool completed() { return _completed; } | |
| 2557 }; | |
| 2558 | |
| 2559 class ClearMarksInHRClosure: public HeapRegionClosure { | |
| 2560 CMBitMap* _bm; | |
| 2561 public: | |
| 2562 ClearMarksInHRClosure(CMBitMap* bm): _bm(bm) { } | |
| 2563 | |
| 2564 bool doHeapRegion(HeapRegion* r) { | |
| 2565 if (!r->used_region().is_empty() && !r->evacuation_failed()) { | |
| 2566 MemRegion usedMR = r->used_region(); | |
| 2567 _bm->clearRange(r->used_region()); | |
| 2568 } | |
| 2569 return false; | |
| 2570 } | |
| 2571 }; | |
| 2572 | |
| 2573 void ConcurrentMark::complete_marking_in_collection_set() { | |
| 2574 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
| 2575 | |
| 2576 if (!g1h->mark_in_progress()) { | |
| 2577 g1h->g1_policy()->record_mark_closure_time(0.0); | |
| 2578 return; | |
| 2579 } | |
| 2580 | |
| 2581 int i = 1; | |
| 2582 double start = os::elapsedTime(); | |
| 2583 while (true) { | |
| 2584 i++; | |
| 2585 CompleteMarkingInCSHRClosure cmplt(this); | |
| 2586 g1h->collection_set_iterate(&cmplt); | |
| 2587 if (cmplt.completed()) break; | |
| 2588 } | |
| 2589 double end_time = os::elapsedTime(); | |
| 2590 double elapsed_time_ms = (end_time - start) * 1000.0; | |
| 2591 g1h->g1_policy()->record_mark_closure_time(elapsed_time_ms); | |
| 2592 | |
| 2593 ClearMarksInHRClosure clr(nextMarkBitMap()); | |
| 2594 g1h->collection_set_iterate(&clr); | |
| 2595 } | |
| 2596 | |
| 2597 // The next two methods deal with the following optimisation. Some | |
| 2598 // objects are gray by being marked and located above the finger. If | |
| 2599 // they are copied, during an evacuation pause, below the finger then | |
| 2600 // the need to be pushed on the stack. The observation is that, if | |
| 2601 // there are no regions in the collection set located above the | |
| 2602 // finger, then the above cannot happen, hence we do not need to | |
| 2603 // explicitly gray any objects when copying them to below the | |
| 2604 // finger. The global stack will be scanned to ensure that, if it | |
| 2605 // points to objects being copied, it will update their | |
| 2606 // location. There is a tricky situation with the gray objects in | |
| 2607 // region stack that are being coped, however. See the comment in | |
| 2608 // newCSet(). | |
| 2609 | |
| 2610 void ConcurrentMark::newCSet() { | |
| 2611 if (!concurrent_marking_in_progress()) | |
| 2612 // nothing to do if marking is not in progress | |
| 2613 return; | |
| 2614 | |
| 2615 // find what the lowest finger is among the global and local fingers | |
| 2616 _min_finger = _finger; | |
| 2617 for (int i = 0; i < (int)_max_task_num; ++i) { | |
| 2618 CMTask* task = _tasks[i]; | |
| 2619 HeapWord* task_finger = task->finger(); | |
| 2620 if (task_finger != NULL && task_finger < _min_finger) | |
| 2621 _min_finger = task_finger; | |
| 2622 } | |
| 2623 | |
| 2624 _should_gray_objects = false; | |
| 2625 | |
| 2626 // This fixes a very subtle and fustrating bug. It might be the case | |
| 2627 // that, during en evacuation pause, heap regions that contain | |
| 2628 // objects that are gray (by being in regions contained in the | |
| 2629 // region stack) are included in the collection set. Since such gray | |
| 2630 // objects will be moved, and because it's not easy to redirect | |
| 2631 // region stack entries to point to a new location (because objects | |
| 2632 // in one region might be scattered to multiple regions after they | |
| 2633 // are copied), one option is to ensure that all marked objects | |
| 2634 // copied during a pause are pushed on the stack. Notice, however, | |
| 2635 // that this problem can only happen when the region stack is not | |
| 2636 // empty during an evacuation pause. So, we make the fix a bit less | |
| 2637 // conservative and ensure that regions are pushed on the stack, | |
| 2638 // irrespective whether all collection set regions are below the | |
| 2639 // finger, if the region stack is not empty. This is expected to be | |
| 2640 // a rare case, so I don't think it's necessary to be smarted about it. | |
| 2641 if (!region_stack_empty()) | |
| 2642 _should_gray_objects = true; | |
| 2643 } | |
| 2644 | |
| 2645 void ConcurrentMark::registerCSetRegion(HeapRegion* hr) { | |
| 2646 if (!concurrent_marking_in_progress()) | |
| 2647 return; | |
| 2648 | |
| 2649 HeapWord* region_end = hr->end(); | |
| 2650 if (region_end > _min_finger) | |
| 2651 _should_gray_objects = true; | |
| 2652 } | |
| 2653 | |
| 2654 // abandon current marking iteration due to a Full GC | |
| 2655 void ConcurrentMark::abort() { | |
| 2656 // Clear all marks to force marking thread to do nothing | |
| 2657 _nextMarkBitMap->clearAll(); | |
| 2658 // Empty mark stack | |
| 2659 clear_marking_state(); | |
| 2660 for (int i = 0; i < (int)_max_task_num; ++i) | |
| 2661 _tasks[i]->clear_region_fields(); | |
| 2662 _has_aborted = true; | |
| 2663 | |
| 2664 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 2665 satb_mq_set.abandon_partial_marking(); | |
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2666 // This can be called either during or outside marking, we'll read |
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2667 // the expected_active value from the SATB queue set. |
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2668 satb_mq_set.set_active_all_threads( |
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2669 false, /* new active value */ |
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2670 satb_mq_set.is_active() /* expected_active */); |
| 342 | 2671 } |
| 2672 | |
| 2673 static void print_ms_time_info(const char* prefix, const char* name, | |
| 2674 NumberSeq& ns) { | |
| 2675 gclog_or_tty->print_cr("%s%5d %12s: total time = %8.2f s (avg = %8.2f ms).", | |
| 2676 prefix, ns.num(), name, ns.sum()/1000.0, ns.avg()); | |
| 2677 if (ns.num() > 0) { | |
| 2678 gclog_or_tty->print_cr("%s [std. dev = %8.2f ms, max = %8.2f ms]", | |
| 2679 prefix, ns.sd(), ns.maximum()); | |
| 2680 } | |
| 2681 } | |
| 2682 | |
| 2683 void ConcurrentMark::print_summary_info() { | |
| 2684 gclog_or_tty->print_cr(" Concurrent marking:"); | |
| 2685 print_ms_time_info(" ", "init marks", _init_times); | |
| 2686 print_ms_time_info(" ", "remarks", _remark_times); | |
| 2687 { | |
| 2688 print_ms_time_info(" ", "final marks", _remark_mark_times); | |
| 2689 print_ms_time_info(" ", "weak refs", _remark_weak_ref_times); | |
| 2690 | |
| 2691 } | |
| 2692 print_ms_time_info(" ", "cleanups", _cleanup_times); | |
| 2693 gclog_or_tty->print_cr(" Final counting total time = %8.2f s (avg = %8.2f ms).", | |
| 2694 _total_counting_time, | |
| 2695 (_cleanup_times.num() > 0 ? _total_counting_time * 1000.0 / | |
| 2696 (double)_cleanup_times.num() | |
| 2697 : 0.0)); | |
| 2698 if (G1ScrubRemSets) { | |
| 2699 gclog_or_tty->print_cr(" RS scrub total time = %8.2f s (avg = %8.2f ms).", | |
| 2700 _total_rs_scrub_time, | |
| 2701 (_cleanup_times.num() > 0 ? _total_rs_scrub_time * 1000.0 / | |
| 2702 (double)_cleanup_times.num() | |
| 2703 : 0.0)); | |
| 2704 } | |
| 2705 gclog_or_tty->print_cr(" Total stop_world time = %8.2f s.", | |
| 2706 (_init_times.sum() + _remark_times.sum() + | |
| 2707 _cleanup_times.sum())/1000.0); | |
| 2708 gclog_or_tty->print_cr(" Total concurrent time = %8.2f s " | |
| 2709 "(%8.2f s marking, %8.2f s counting).", | |
| 2710 cmThread()->vtime_accum(), | |
| 2711 cmThread()->vtime_mark_accum(), | |
| 2712 cmThread()->vtime_count_accum()); | |
| 2713 } | |
| 2714 | |
| 1019 | 2715 void ConcurrentMark::print_worker_threads_on(outputStream* st) const { |
| 2716 _parallel_workers->print_worker_threads_on(st); | |
| 2717 } | |
| 2718 | |
| 342 | 2719 // Closures |
| 2720 // XXX: there seems to be a lot of code duplication here; | |
| 2721 // should refactor and consolidate the shared code. | |
| 2722 | |
| 2723 // This closure is used to mark refs into the CMS generation in | |
| 2724 // the CMS bit map. Called at the first checkpoint. | |
| 2725 | |
| 2726 // We take a break if someone is trying to stop the world. | |
| 2727 bool ConcurrentMark::do_yield_check(int worker_i) { | |
| 2728 if (should_yield()) { | |
| 2729 if (worker_i == 0) | |
| 2730 _g1h->g1_policy()->record_concurrent_pause(); | |
| 2731 cmThread()->yield(); | |
| 2732 if (worker_i == 0) | |
| 2733 _g1h->g1_policy()->record_concurrent_pause_end(); | |
| 2734 return true; | |
| 2735 } else { | |
| 2736 return false; | |
| 2737 } | |
| 2738 } | |
| 2739 | |
| 2740 bool ConcurrentMark::should_yield() { | |
| 2741 return cmThread()->should_yield(); | |
| 2742 } | |
| 2743 | |
| 2744 bool ConcurrentMark::containing_card_is_marked(void* p) { | |
| 2745 size_t offset = pointer_delta(p, _g1h->reserved_region().start(), 1); | |
| 2746 return _card_bm.at(offset >> CardTableModRefBS::card_shift); | |
| 2747 } | |
| 2748 | |
| 2749 bool ConcurrentMark::containing_cards_are_marked(void* start, | |
| 2750 void* last) { | |
| 2751 return | |
| 2752 containing_card_is_marked(start) && | |
| 2753 containing_card_is_marked(last); | |
| 2754 } | |
| 2755 | |
| 2756 #ifndef PRODUCT | |
| 2757 // for debugging purposes | |
| 2758 void ConcurrentMark::print_finger() { | |
| 2759 gclog_or_tty->print_cr("heap ["PTR_FORMAT", "PTR_FORMAT"), global finger = "PTR_FORMAT, | |
| 2760 _heap_start, _heap_end, _finger); | |
| 2761 for (int i = 0; i < (int) _max_task_num; ++i) { | |
| 2762 gclog_or_tty->print(" %d: "PTR_FORMAT, i, _tasks[i]->finger()); | |
| 2763 } | |
| 2764 gclog_or_tty->print_cr(""); | |
| 2765 } | |
| 2766 #endif | |
| 2767 | |
| 2768 // Closure for iteration over bitmaps | |
| 2769 class CMBitMapClosure : public BitMapClosure { | |
| 2770 private: | |
| 2771 // the bitmap that is being iterated over | |
| 2772 CMBitMap* _nextMarkBitMap; | |
| 2773 ConcurrentMark* _cm; | |
| 2774 CMTask* _task; | |
| 2775 // true if we're scanning a heap region claimed by the task (so that | |
| 2776 // we move the finger along), false if we're not, i.e. currently when | |
| 2777 // scanning a heap region popped from the region stack (so that we | |
| 2778 // do not move the task finger along; it'd be a mistake if we did so). | |
| 2779 bool _scanning_heap_region; | |
| 2780 | |
| 2781 public: | |
| 2782 CMBitMapClosure(CMTask *task, | |
| 2783 ConcurrentMark* cm, | |
| 2784 CMBitMap* nextMarkBitMap) | |
| 2785 : _task(task), _cm(cm), _nextMarkBitMap(nextMarkBitMap) { } | |
| 2786 | |
| 2787 void set_scanning_heap_region(bool scanning_heap_region) { | |
| 2788 _scanning_heap_region = scanning_heap_region; | |
| 2789 } | |
| 2790 | |
| 2791 bool do_bit(size_t offset) { | |
| 2792 HeapWord* addr = _nextMarkBitMap->offsetToHeapWord(offset); | |
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2793 assert(_nextMarkBitMap->isMarked(addr), "invariant"); |
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2794 assert( addr < _cm->finger(), "invariant"); |
| 342 | 2795 |
| 2796 if (_scanning_heap_region) { | |
| 2797 statsOnly( _task->increase_objs_found_on_bitmap() ); | |
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2798 assert(addr >= _task->finger(), "invariant"); |
| 342 | 2799 // We move that task's local finger along. |
| 2800 _task->move_finger_to(addr); | |
| 2801 } else { | |
| 2802 // We move the task's region finger along. | |
| 2803 _task->move_region_finger_to(addr); | |
| 2804 } | |
| 2805 | |
| 2806 _task->scan_object(oop(addr)); | |
| 2807 // we only partially drain the local queue and global stack | |
| 2808 _task->drain_local_queue(true); | |
| 2809 _task->drain_global_stack(true); | |
| 2810 | |
| 2811 // if the has_aborted flag has been raised, we need to bail out of | |
| 2812 // the iteration | |
| 2813 return !_task->has_aborted(); | |
| 2814 } | |
| 2815 }; | |
| 2816 | |
| 2817 // Closure for iterating over objects, currently only used for | |
| 2818 // processing SATB buffers. | |
| 2819 class CMObjectClosure : public ObjectClosure { | |
| 2820 private: | |
| 2821 CMTask* _task; | |
| 2822 | |
| 2823 public: | |
| 2824 void do_object(oop obj) { | |
| 2825 _task->deal_with_reference(obj); | |
| 2826 } | |
| 2827 | |
| 2828 CMObjectClosure(CMTask* task) : _task(task) { } | |
| 2829 }; | |
| 2830 | |
| 2831 // Closure for iterating over object fields | |
| 2832 class CMOopClosure : public OopClosure { | |
| 2833 private: | |
| 2834 G1CollectedHeap* _g1h; | |
| 2835 ConcurrentMark* _cm; | |
| 2836 CMTask* _task; | |
| 2837 | |
| 2838 public: | |
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2839 virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
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2840 virtual void do_oop( oop* p) { do_oop_work(p); } |
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2841 |
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2842 template <class T> void do_oop_work(T* p) { |
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2843 assert(_g1h->is_in_g1_reserved((HeapWord*) p), "invariant"); |
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2844 assert(!_g1h->heap_region_containing((HeapWord*) p)->is_on_free_list(), |
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2845 "invariant"); |
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2846 |
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2847 oop obj = oopDesc::load_decode_heap_oop(p); |
| 342 | 2848 if (_cm->verbose_high()) |
| 2849 gclog_or_tty->print_cr("[%d] we're looking at location " | |
| 2850 "*"PTR_FORMAT" = "PTR_FORMAT, | |
| 2851 _task->task_id(), p, (void*) obj); | |
| 2852 _task->deal_with_reference(obj); | |
| 2853 } | |
| 2854 | |
| 2855 CMOopClosure(G1CollectedHeap* g1h, | |
| 2856 ConcurrentMark* cm, | |
| 2857 CMTask* task) | |
| 2858 : _g1h(g1h), _cm(cm), _task(task) { } | |
| 2859 }; | |
| 2860 | |
| 2861 void CMTask::setup_for_region(HeapRegion* hr) { | |
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2862 // Separated the asserts so that we know which one fires. |
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2863 assert(hr != NULL, |
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2864 "claim_region() should have filtered out continues humongous regions"); |
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2865 assert(!hr->continuesHumongous(), |
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2866 "claim_region() should have filtered out continues humongous regions"); |
| 342 | 2867 |
| 2868 if (_cm->verbose_low()) | |
| 2869 gclog_or_tty->print_cr("[%d] setting up for region "PTR_FORMAT, | |
| 2870 _task_id, hr); | |
| 2871 | |
| 2872 _curr_region = hr; | |
| 2873 _finger = hr->bottom(); | |
| 2874 update_region_limit(); | |
| 2875 } | |
| 2876 | |
| 2877 void CMTask::update_region_limit() { | |
| 2878 HeapRegion* hr = _curr_region; | |
| 2879 HeapWord* bottom = hr->bottom(); | |
| 2880 HeapWord* limit = hr->next_top_at_mark_start(); | |
| 2881 | |
| 2882 if (limit == bottom) { | |
| 2883 if (_cm->verbose_low()) | |
| 2884 gclog_or_tty->print_cr("[%d] found an empty region " | |
| 2885 "["PTR_FORMAT", "PTR_FORMAT")", | |
| 2886 _task_id, bottom, limit); | |
| 2887 // The region was collected underneath our feet. | |
| 2888 // We set the finger to bottom to ensure that the bitmap | |
| 2889 // iteration that will follow this will not do anything. | |
| 2890 // (this is not a condition that holds when we set the region up, | |
| 2891 // as the region is not supposed to be empty in the first place) | |
| 2892 _finger = bottom; | |
| 2893 } else if (limit >= _region_limit) { | |
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2894 assert(limit >= _finger, "peace of mind"); |
| 342 | 2895 } else { |
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2896 assert(limit < _region_limit, "only way to get here"); |
| 342 | 2897 // This can happen under some pretty unusual circumstances. An |
| 2898 // evacuation pause empties the region underneath our feet (NTAMS | |
| 2899 // at bottom). We then do some allocation in the region (NTAMS | |
| 2900 // stays at bottom), followed by the region being used as a GC | |
| 2901 // alloc region (NTAMS will move to top() and the objects | |
| 2902 // originally below it will be grayed). All objects now marked in | |
| 2903 // the region are explicitly grayed, if below the global finger, | |
| 2904 // and we do not need in fact to scan anything else. So, we simply | |
| 2905 // set _finger to be limit to ensure that the bitmap iteration | |
| 2906 // doesn't do anything. | |
| 2907 _finger = limit; | |
| 2908 } | |
| 2909 | |
| 2910 _region_limit = limit; | |
| 2911 } | |
| 2912 | |
| 2913 void CMTask::giveup_current_region() { | |
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2914 assert(_curr_region != NULL, "invariant"); |
| 342 | 2915 if (_cm->verbose_low()) |
| 2916 gclog_or_tty->print_cr("[%d] giving up region "PTR_FORMAT, | |
| 2917 _task_id, _curr_region); | |
| 2918 clear_region_fields(); | |
| 2919 } | |
| 2920 | |
| 2921 void CMTask::clear_region_fields() { | |
| 2922 // Values for these three fields that indicate that we're not | |
| 2923 // holding on to a region. | |
| 2924 _curr_region = NULL; | |
| 2925 _finger = NULL; | |
| 2926 _region_limit = NULL; | |
| 2927 | |
| 2928 _region_finger = NULL; | |
| 2929 } | |
| 2930 | |
| 2931 void CMTask::reset(CMBitMap* nextMarkBitMap) { | |
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2932 guarantee(nextMarkBitMap != NULL, "invariant"); |
| 342 | 2933 |
| 2934 if (_cm->verbose_low()) | |
| 2935 gclog_or_tty->print_cr("[%d] resetting", _task_id); | |
| 2936 | |
| 2937 _nextMarkBitMap = nextMarkBitMap; | |
| 2938 clear_region_fields(); | |
| 2939 | |
| 2940 _calls = 0; | |
| 2941 _elapsed_time_ms = 0.0; | |
| 2942 _termination_time_ms = 0.0; | |
| 2943 _termination_start_time_ms = 0.0; | |
| 2944 | |
| 2945 #if _MARKING_STATS_ | |
| 2946 _local_pushes = 0; | |
| 2947 _local_pops = 0; | |
| 2948 _local_max_size = 0; | |
| 2949 _objs_scanned = 0; | |
| 2950 _global_pushes = 0; | |
| 2951 _global_pops = 0; | |
| 2952 _global_max_size = 0; | |
| 2953 _global_transfers_to = 0; | |
| 2954 _global_transfers_from = 0; | |
| 2955 _region_stack_pops = 0; | |
| 2956 _regions_claimed = 0; | |
| 2957 _objs_found_on_bitmap = 0; | |
| 2958 _satb_buffers_processed = 0; | |
| 2959 _steal_attempts = 0; | |
| 2960 _steals = 0; | |
| 2961 _aborted = 0; | |
| 2962 _aborted_overflow = 0; | |
| 2963 _aborted_cm_aborted = 0; | |
| 2964 _aborted_yield = 0; | |
| 2965 _aborted_timed_out = 0; | |
| 2966 _aborted_satb = 0; | |
| 2967 _aborted_termination = 0; | |
| 2968 #endif // _MARKING_STATS_ | |
| 2969 } | |
| 2970 | |
| 2971 bool CMTask::should_exit_termination() { | |
| 2972 regular_clock_call(); | |
| 2973 // This is called when we are in the termination protocol. We should | |
| 2974 // quit if, for some reason, this task wants to abort or the global | |
| 2975 // stack is not empty (this means that we can get work from it). | |
| 2976 return !_cm->mark_stack_empty() || has_aborted(); | |
| 2977 } | |
| 2978 | |
| 2979 // This determines whether the method below will check both the local | |
| 2980 // and global fingers when determining whether to push on the stack a | |
| 2981 // gray object (value 1) or whether it will only check the global one | |
| 2982 // (value 0). The tradeoffs are that the former will be a bit more | |
| 2983 // accurate and possibly push less on the stack, but it might also be | |
| 2984 // a little bit slower. | |
| 2985 | |
| 2986 #define _CHECK_BOTH_FINGERS_ 1 | |
| 2987 | |
| 2988 void CMTask::deal_with_reference(oop obj) { | |
| 2989 if (_cm->verbose_high()) | |
| 2990 gclog_or_tty->print_cr("[%d] we're dealing with reference = "PTR_FORMAT, | |
| 2991 _task_id, (void*) obj); | |
| 2992 | |
| 2993 ++_refs_reached; | |
| 2994 | |
| 2995 HeapWord* objAddr = (HeapWord*) obj; | |
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2996 assert(obj->is_oop_or_null(true /* ignore mark word */), "Error"); |
| 342 | 2997 if (_g1h->is_in_g1_reserved(objAddr)) { |
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2998 assert(obj != NULL, "is_in_g1_reserved should ensure this"); |
| 342 | 2999 HeapRegion* hr = _g1h->heap_region_containing(obj); |
| 3000 if (_g1h->is_obj_ill(obj, hr)) { | |
| 3001 if (_cm->verbose_high()) | |
| 3002 gclog_or_tty->print_cr("[%d] "PTR_FORMAT" is not considered marked", | |
| 3003 _task_id, (void*) obj); | |
| 3004 | |
| 3005 // we need to mark it first | |
| 3006 if (_nextMarkBitMap->parMark(objAddr)) { | |
| 3007 // No OrderAccess:store_load() is needed. It is implicit in the | |
| 3008 // CAS done in parMark(objAddr) above | |
| 3009 HeapWord* global_finger = _cm->finger(); | |
| 3010 | |
| 3011 #if _CHECK_BOTH_FINGERS_ | |
| 3012 // we will check both the local and global fingers | |
| 3013 | |
| 3014 if (_finger != NULL && objAddr < _finger) { | |
| 3015 if (_cm->verbose_high()) | |
| 3016 gclog_or_tty->print_cr("[%d] below the local finger ("PTR_FORMAT"), " | |
| 3017 "pushing it", _task_id, _finger); | |
| 3018 push(obj); | |
| 3019 } else if (_curr_region != NULL && objAddr < _region_limit) { | |
| 3020 // do nothing | |
| 3021 } else if (objAddr < global_finger) { | |
| 3022 // Notice that the global finger might be moving forward | |
| 3023 // concurrently. This is not a problem. In the worst case, we | |
| 3024 // mark the object while it is above the global finger and, by | |
| 3025 // the time we read the global finger, it has moved forward | |
| 3026 // passed this object. In this case, the object will probably | |
| 3027 // be visited when a task is scanning the region and will also | |
| 3028 // be pushed on the stack. So, some duplicate work, but no | |
| 3029 // correctness problems. | |
| 3030 | |
| 3031 if (_cm->verbose_high()) | |
| 3032 gclog_or_tty->print_cr("[%d] below the global finger " | |
| 3033 "("PTR_FORMAT"), pushing it", | |
| 3034 _task_id, global_finger); | |
| 3035 push(obj); | |
| 3036 } else { | |
| 3037 // do nothing | |
| 3038 } | |
| 3039 #else // _CHECK_BOTH_FINGERS_ | |
| 3040 // we will only check the global finger | |
| 3041 | |
| 3042 if (objAddr < global_finger) { | |
| 3043 // see long comment above | |
| 3044 | |
| 3045 if (_cm->verbose_high()) | |
| 3046 gclog_or_tty->print_cr("[%d] below the global finger " | |
| 3047 "("PTR_FORMAT"), pushing it", | |
| 3048 _task_id, global_finger); | |
| 3049 push(obj); | |
| 3050 } | |
| 3051 #endif // _CHECK_BOTH_FINGERS_ | |
| 3052 } | |
| 3053 } | |
| 3054 } | |
| 3055 } | |
| 3056 | |
| 3057 void CMTask::push(oop obj) { | |
| 3058 HeapWord* objAddr = (HeapWord*) obj; | |
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3059 assert(_g1h->is_in_g1_reserved(objAddr), "invariant"); |
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3060 assert(!_g1h->heap_region_containing(objAddr)->is_on_free_list(), |
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3061 "invariant"); |
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3062 assert(!_g1h->is_obj_ill(obj), "invariant"); |
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3063 assert(_nextMarkBitMap->isMarked(objAddr), "invariant"); |
| 342 | 3064 |
| 3065 if (_cm->verbose_high()) | |
| 3066 gclog_or_tty->print_cr("[%d] pushing "PTR_FORMAT, _task_id, (void*) obj); | |
| 3067 | |
| 3068 if (!_task_queue->push(obj)) { | |
| 3069 // The local task queue looks full. We need to push some entries | |
| 3070 // to the global stack. | |
| 3071 | |
| 3072 if (_cm->verbose_medium()) | |
| 3073 gclog_or_tty->print_cr("[%d] task queue overflow, " | |
| 3074 "moving entries to the global stack", | |
| 3075 _task_id); | |
| 3076 move_entries_to_global_stack(); | |
| 3077 | |
| 3078 // this should succeed since, even if we overflow the global | |
| 3079 // stack, we should have definitely removed some entries from the | |
| 3080 // local queue. So, there must be space on it. | |
| 3081 bool success = _task_queue->push(obj); | |
|
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3082 assert(success, "invariant"); |
| 342 | 3083 } |
| 3084 | |
| 3085 statsOnly( int tmp_size = _task_queue->size(); | |
| 3086 if (tmp_size > _local_max_size) | |
| 3087 _local_max_size = tmp_size; | |
| 3088 ++_local_pushes ); | |
| 3089 } | |
| 3090 | |
| 3091 void CMTask::reached_limit() { | |
|
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3092 assert(_words_scanned >= _words_scanned_limit || |
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3093 _refs_reached >= _refs_reached_limit , |
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3094 "shouldn't have been called otherwise"); |
| 342 | 3095 regular_clock_call(); |
| 3096 } | |
| 3097 | |
| 3098 void CMTask::regular_clock_call() { | |
| 3099 if (has_aborted()) | |
| 3100 return; | |
| 3101 | |
| 3102 // First, we need to recalculate the words scanned and refs reached | |
| 3103 // limits for the next clock call. | |
| 3104 recalculate_limits(); | |
| 3105 | |
| 3106 // During the regular clock call we do the following | |
| 3107 | |
| 3108 // (1) If an overflow has been flagged, then we abort. | |
| 3109 if (_cm->has_overflown()) { | |
| 3110 set_has_aborted(); | |
| 3111 return; | |
| 3112 } | |
| 3113 | |
| 3114 // If we are not concurrent (i.e. we're doing remark) we don't need | |
| 3115 // to check anything else. The other steps are only needed during | |
| 3116 // the concurrent marking phase. | |
| 3117 if (!concurrent()) | |
| 3118 return; | |
| 3119 | |
| 3120 // (2) If marking has been aborted for Full GC, then we also abort. | |
| 3121 if (_cm->has_aborted()) { | |
| 3122 set_has_aborted(); | |
| 3123 statsOnly( ++_aborted_cm_aborted ); | |
| 3124 return; | |
| 3125 } | |
| 3126 | |
| 3127 double curr_time_ms = os::elapsedVTime() * 1000.0; | |
| 3128 | |
| 3129 // (3) If marking stats are enabled, then we update the step history. | |
| 3130 #if _MARKING_STATS_ | |
| 3131 if (_words_scanned >= _words_scanned_limit) | |
| 3132 ++_clock_due_to_scanning; | |
| 3133 if (_refs_reached >= _refs_reached_limit) | |
| 3134 ++_clock_due_to_marking; | |
| 3135 | |
| 3136 double last_interval_ms = curr_time_ms - _interval_start_time_ms; | |
| 3137 _interval_start_time_ms = curr_time_ms; | |
| 3138 _all_clock_intervals_ms.add(last_interval_ms); | |
| 3139 | |
| 3140 if (_cm->verbose_medium()) { | |
| 3141 gclog_or_tty->print_cr("[%d] regular clock, interval = %1.2lfms, " | |
| 3142 "scanned = %d%s, refs reached = %d%s", | |
| 3143 _task_id, last_interval_ms, | |
| 3144 _words_scanned, | |
| 3145 (_words_scanned >= _words_scanned_limit) ? " (*)" : "", | |
| 3146 _refs_reached, | |
| 3147 (_refs_reached >= _refs_reached_limit) ? " (*)" : ""); | |
| 3148 } | |
| 3149 #endif // _MARKING_STATS_ | |
| 3150 | |
| 3151 // (4) We check whether we should yield. If we have to, then we abort. | |
| 3152 if (_cm->should_yield()) { | |
| 3153 // We should yield. To do this we abort the task. The caller is | |
| 3154 // responsible for yielding. | |
| 3155 set_has_aborted(); | |
| 3156 statsOnly( ++_aborted_yield ); | |
| 3157 return; | |
| 3158 } | |
| 3159 | |
| 3160 // (5) We check whether we've reached our time quota. If we have, | |
| 3161 // then we abort. | |
| 3162 double elapsed_time_ms = curr_time_ms - _start_time_ms; | |
| 3163 if (elapsed_time_ms > _time_target_ms) { | |
| 3164 set_has_aborted(); | |
| 3165 _has_aborted_timed_out = true; | |
| 3166 statsOnly( ++_aborted_timed_out ); | |
| 3167 return; | |
| 3168 } | |
| 3169 | |
| 3170 // (6) Finally, we check whether there are enough completed STAB | |
| 3171 // buffers available for processing. If there are, we abort. | |
| 3172 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
| 3173 if (!_draining_satb_buffers && satb_mq_set.process_completed_buffers()) { | |
| 3174 if (_cm->verbose_low()) | |
| 3175 gclog_or_tty->print_cr("[%d] aborting to deal with pending SATB buffers", | |
| 3176 _task_id); | |
| 3177 // we do need to process SATB buffers, we'll abort and restart | |
| 3178 // the marking task to do so | |
| 3179 set_has_aborted(); | |
| 3180 statsOnly( ++_aborted_satb ); | |
| 3181 return; | |
| 3182 } | |
| 3183 } | |
| 3184 | |
| 3185 void CMTask::recalculate_limits() { | |
| 3186 _real_words_scanned_limit = _words_scanned + words_scanned_period; | |
| 3187 _words_scanned_limit = _real_words_scanned_limit; | |
| 3188 | |
| 3189 _real_refs_reached_limit = _refs_reached + refs_reached_period; | |
| 3190 _refs_reached_limit = _real_refs_reached_limit; | |
| 3191 } | |
| 3192 | |
| 3193 void CMTask::decrease_limits() { | |
| 3194 // This is called when we believe that we're going to do an infrequent | |
| 3195 // operation which will increase the per byte scanned cost (i.e. move | |
| 3196 // entries to/from the global stack). It basically tries to decrease the | |
| 3197 // scanning limit so that the clock is called earlier. | |
| 3198 | |
| 3199 if (_cm->verbose_medium()) | |
| 3200 gclog_or_tty->print_cr("[%d] decreasing limits", _task_id); | |
| 3201 | |
| 3202 _words_scanned_limit = _real_words_scanned_limit - | |
| 3203 3 * words_scanned_period / 4; | |
| 3204 _refs_reached_limit = _real_refs_reached_limit - | |
| 3205 3 * refs_reached_period / 4; | |
| 3206 } | |
| 3207 | |
| 3208 void CMTask::move_entries_to_global_stack() { | |
| 3209 // local array where we'll store the entries that will be popped | |
| 3210 // from the local queue | |
| 3211 oop buffer[global_stack_transfer_size]; | |
| 3212 | |
| 3213 int n = 0; | |
| 3214 oop obj; | |
| 3215 while (n < global_stack_transfer_size && _task_queue->pop_local(obj)) { | |
| 3216 buffer[n] = obj; | |
| 3217 ++n; | |
| 3218 } | |
| 3219 | |
| 3220 if (n > 0) { | |
| 3221 // we popped at least one entry from the local queue | |
| 3222 | |
| 3223 statsOnly( ++_global_transfers_to; _local_pops += n ); | |
| 3224 | |
| 3225 if (!_cm->mark_stack_push(buffer, n)) { | |
| 3226 if (_cm->verbose_low()) | |
| 3227 gclog_or_tty->print_cr("[%d] aborting due to global stack overflow", _task_id); | |
| 3228 set_has_aborted(); | |
| 3229 } else { | |
| 3230 // the transfer was successful | |
| 3231 | |
| 3232 if (_cm->verbose_medium()) | |
| 3233 gclog_or_tty->print_cr("[%d] pushed %d entries to the global stack", | |
| 3234 _task_id, n); | |
| 3235 statsOnly( int tmp_size = _cm->mark_stack_size(); | |
| 3236 if (tmp_size > _global_max_size) | |
| 3237 _global_max_size = tmp_size; | |
| 3238 _global_pushes += n ); | |
| 3239 } | |
| 3240 } | |
| 3241 | |
| 3242 // this operation was quite expensive, so decrease the limits | |
| 3243 decrease_limits(); | |
| 3244 } | |
| 3245 | |
| 3246 void CMTask::get_entries_from_global_stack() { | |
| 3247 // local array where we'll store the entries that will be popped | |
| 3248 // from the global stack. | |
| 3249 oop buffer[global_stack_transfer_size]; | |
| 3250 int n; | |
| 3251 _cm->mark_stack_pop(buffer, global_stack_transfer_size, &n); | |
|
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3252 assert(n <= global_stack_transfer_size, |
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3253 "we should not pop more than the given limit"); |
| 342 | 3254 if (n > 0) { |
| 3255 // yes, we did actually pop at least one entry | |
| 3256 | |
| 3257 statsOnly( ++_global_transfers_from; _global_pops += n ); | |
| 3258 if (_cm->verbose_medium()) | |
| 3259 gclog_or_tty->print_cr("[%d] popped %d entries from the global stack", | |
| 3260 _task_id, n); | |
| 3261 for (int i = 0; i < n; ++i) { | |
| 3262 bool success = _task_queue->push(buffer[i]); | |
| 3263 // We only call this when the local queue is empty or under a | |
| 3264 // given target limit. So, we do not expect this push to fail. | |
|
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3265 assert(success, "invariant"); |
| 342 | 3266 } |
| 3267 | |
| 3268 statsOnly( int tmp_size = _task_queue->size(); | |
| 3269 if (tmp_size > _local_max_size) | |
| 3270 _local_max_size = tmp_size; | |
| 3271 _local_pushes += n ); | |
| 3272 } | |
| 3273 | |
| 3274 // this operation was quite expensive, so decrease the limits | |
| 3275 decrease_limits(); | |
| 3276 } | |
| 3277 | |
| 3278 void CMTask::drain_local_queue(bool partially) { | |
| 3279 if (has_aborted()) | |
| 3280 return; | |
| 3281 | |
| 3282 // Decide what the target size is, depending whether we're going to | |
| 3283 // drain it partially (so that other tasks can steal if they run out | |
| 3284 // of things to do) or totally (at the very end). | |
| 3285 size_t target_size; | |
| 3286 if (partially) | |
| 3287 target_size = MIN2((size_t)_task_queue->max_elems()/3, GCDrainStackTargetSize); | |
| 3288 else | |
| 3289 target_size = 0; | |
| 3290 | |
| 3291 if (_task_queue->size() > target_size) { | |
| 3292 if (_cm->verbose_high()) | |
| 3293 gclog_or_tty->print_cr("[%d] draining local queue, target size = %d", | |
| 3294 _task_id, target_size); | |
| 3295 | |
| 3296 oop obj; | |
| 3297 bool ret = _task_queue->pop_local(obj); | |
| 3298 while (ret) { | |
| 3299 statsOnly( ++_local_pops ); | |
| 3300 | |
| 3301 if (_cm->verbose_high()) | |
| 3302 gclog_or_tty->print_cr("[%d] popped "PTR_FORMAT, _task_id, | |
| 3303 (void*) obj); | |
| 3304 | |
|
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3305 assert(_g1h->is_in_g1_reserved((HeapWord*) obj), "invariant" ); |
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3306 assert(!_g1h->heap_region_containing(obj)->is_on_free_list(), |
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3307 "invariant"); |
| 342 | 3308 |
| 3309 scan_object(obj); | |
| 3310 | |
| 3311 if (_task_queue->size() <= target_size || has_aborted()) | |
| 3312 ret = false; | |
| 3313 else | |
| 3314 ret = _task_queue->pop_local(obj); | |
| 3315 } | |
| 3316 | |
| 3317 if (_cm->verbose_high()) | |
| 3318 gclog_or_tty->print_cr("[%d] drained local queue, size = %d", | |
| 3319 _task_id, _task_queue->size()); | |
| 3320 } | |
| 3321 } | |
| 3322 | |
| 3323 void CMTask::drain_global_stack(bool partially) { | |
| 3324 if (has_aborted()) | |
| 3325 return; | |
| 3326 | |
| 3327 // We have a policy to drain the local queue before we attempt to | |
| 3328 // drain the global stack. | |
|
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3329 assert(partially || _task_queue->size() == 0, "invariant"); |
| 342 | 3330 |
| 3331 // Decide what the target size is, depending whether we're going to | |
| 3332 // drain it partially (so that other tasks can steal if they run out | |
| 3333 // of things to do) or totally (at the very end). Notice that, | |
| 3334 // because we move entries from the global stack in chunks or | |
| 3335 // because another task might be doing the same, we might in fact | |
| 3336 // drop below the target. But, this is not a problem. | |
| 3337 size_t target_size; | |
| 3338 if (partially) | |
| 3339 target_size = _cm->partial_mark_stack_size_target(); | |
| 3340 else | |
| 3341 target_size = 0; | |
| 3342 | |
| 3343 if (_cm->mark_stack_size() > target_size) { | |
| 3344 if (_cm->verbose_low()) | |
| 3345 gclog_or_tty->print_cr("[%d] draining global_stack, target size %d", | |
| 3346 _task_id, target_size); | |
| 3347 | |
| 3348 while (!has_aborted() && _cm->mark_stack_size() > target_size) { | |
| 3349 get_entries_from_global_stack(); | |
| 3350 drain_local_queue(partially); | |
| 3351 } | |
| 3352 | |
| 3353 if (_cm->verbose_low()) | |
| 3354 gclog_or_tty->print_cr("[%d] drained global stack, size = %d", | |
| 3355 _task_id, _cm->mark_stack_size()); | |
| 3356 } | |
| 3357 } | |
| 3358 | |
| 3359 // SATB Queue has several assumptions on whether to call the par or | |
| 3360 // non-par versions of the methods. this is why some of the code is | |
| 3361 // replicated. We should really get rid of the single-threaded version | |
| 3362 // of the code to simplify things. | |
| 3363 void CMTask::drain_satb_buffers() { | |
| 3364 if (has_aborted()) | |
| 3365 return; | |
| 3366 | |
| 3367 // We set this so that the regular clock knows that we're in the | |
| 3368 // middle of draining buffers and doesn't set the abort flag when it | |
| 3369 // notices that SATB buffers are available for draining. It'd be | |
| 3370 // very counter productive if it did that. :-) | |
| 3371 _draining_satb_buffers = true; | |
| 3372 | |
| 3373 CMObjectClosure oc(this); | |
| 3374 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set(); | |
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3375 if (G1CollectedHeap::use_parallel_gc_threads()) |
| 342 | 3376 satb_mq_set.set_par_closure(_task_id, &oc); |
| 3377 else | |
| 3378 satb_mq_set.set_closure(&oc); | |
| 3379 | |
| 3380 // This keeps claiming and applying the closure to completed buffers | |
| 3381 // until we run out of buffers or we need to abort. | |
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3382 if (G1CollectedHeap::use_parallel_gc_threads()) { |
| 342 | 3383 while (!has_aborted() && |
| 3384 satb_mq_set.par_apply_closure_to_completed_buffer(_task_id)) { | |
| 3385 if (_cm->verbose_medium()) | |
| 3386 gclog_or_tty->print_cr("[%d] processed an SATB buffer", _task_id); | |
| 3387 statsOnly( ++_satb_buffers_processed ); | |
| 3388 regular_clock_call(); | |
| 3389 } | |
| 3390 } else { | |
| 3391 while (!has_aborted() && | |
| 3392 satb_mq_set.apply_closure_to_completed_buffer()) { | |
| 3393 if (_cm->verbose_medium()) | |
| 3394 gclog_or_tty->print_cr("[%d] processed an SATB buffer", _task_id); | |
| 3395 statsOnly( ++_satb_buffers_processed ); | |
| 3396 regular_clock_call(); | |
| 3397 } | |
| 3398 } | |
| 3399 | |
| 3400 if (!concurrent() && !has_aborted()) { | |
| 3401 // We should only do this during remark. | |
|
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3402 if (G1CollectedHeap::use_parallel_gc_threads()) |
| 342 | 3403 satb_mq_set.par_iterate_closure_all_threads(_task_id); |
| 3404 else | |
| 3405 satb_mq_set.iterate_closure_all_threads(); | |
| 3406 } | |
| 3407 | |
| 3408 _draining_satb_buffers = false; | |
| 3409 | |
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3410 assert(has_aborted() || |
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3411 concurrent() || |
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3412 satb_mq_set.completed_buffers_num() == 0, "invariant"); |
| 342 | 3413 |
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3414 if (G1CollectedHeap::use_parallel_gc_threads()) |
| 342 | 3415 satb_mq_set.set_par_closure(_task_id, NULL); |
| 3416 else | |
| 3417 satb_mq_set.set_closure(NULL); | |
| 3418 | |
| 3419 // again, this was a potentially expensive operation, decrease the | |
| 3420 // limits to get the regular clock call early | |
| 3421 decrease_limits(); | |
| 3422 } | |
| 3423 | |
| 3424 void CMTask::drain_region_stack(BitMapClosure* bc) { | |
| 3425 if (has_aborted()) | |
| 3426 return; | |
| 3427 | |
|
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3428 assert(_region_finger == NULL, |
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3429 "it should be NULL when we're not scanning a region"); |
| 342 | 3430 |
| 3431 if (!_cm->region_stack_empty()) { | |
| 3432 if (_cm->verbose_low()) | |
| 3433 gclog_or_tty->print_cr("[%d] draining region stack, size = %d", | |
| 3434 _task_id, _cm->region_stack_size()); | |
| 3435 | |
|
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3436 MemRegion mr = _cm->region_stack_pop_with_lock(); |
| 342 | 3437 // it returns MemRegion() if the pop fails |
| 3438 statsOnly(if (mr.start() != NULL) ++_region_stack_pops ); | |
| 3439 | |
| 3440 while (mr.start() != NULL) { | |
| 3441 if (_cm->verbose_medium()) | |
| 3442 gclog_or_tty->print_cr("[%d] we are scanning region " | |
| 3443 "["PTR_FORMAT", "PTR_FORMAT")", | |
| 3444 _task_id, mr.start(), mr.end()); | |
|
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3445 assert(mr.end() <= _cm->finger(), |
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3446 "otherwise the region shouldn't be on the stack"); |
| 342 | 3447 assert(!mr.is_empty(), "Only non-empty regions live on the region stack"); |
| 3448 if (_nextMarkBitMap->iterate(bc, mr)) { | |
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3449 assert(!has_aborted(), |
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3450 "cannot abort the task without aborting the bitmap iteration"); |
| 342 | 3451 |
| 3452 // We finished iterating over the region without aborting. | |
| 3453 regular_clock_call(); | |
| 3454 if (has_aborted()) | |
| 3455 mr = MemRegion(); | |
| 3456 else { | |
|
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3457 mr = _cm->region_stack_pop_with_lock(); |
| 342 | 3458 // it returns MemRegion() if the pop fails |
| 3459 statsOnly(if (mr.start() != NULL) ++_region_stack_pops ); | |
| 3460 } | |
| 3461 } else { | |
|
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3462 assert(has_aborted(), "currently the only way to do so"); |
| 342 | 3463 |
| 3464 // The only way to abort the bitmap iteration is to return | |
| 3465 // false from the do_bit() method. However, inside the | |
| 3466 // do_bit() method we move the _region_finger to point to the | |
| 3467 // object currently being looked at. So, if we bail out, we | |
| 3468 // have definitely set _region_finger to something non-null. | |
|
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3469 assert(_region_finger != NULL, "invariant"); |
| 342 | 3470 |
| 3471 // The iteration was actually aborted. So now _region_finger | |
| 3472 // points to the address of the object we last scanned. If we | |
| 3473 // leave it there, when we restart this task, we will rescan | |
| 3474 // the object. It is easy to avoid this. We move the finger by | |
| 3475 // enough to point to the next possible object header (the | |
| 3476 // bitmap knows by how much we need to move it as it knows its | |
| 3477 // granularity). | |
| 3478 MemRegion newRegion = | |
| 3479 MemRegion(_nextMarkBitMap->nextWord(_region_finger), mr.end()); | |
| 3480 | |
| 3481 if (!newRegion.is_empty()) { | |
| 3482 if (_cm->verbose_low()) { | |
| 3483 gclog_or_tty->print_cr("[%d] pushing unscanned region" | |
| 3484 "[" PTR_FORMAT "," PTR_FORMAT ") on region stack", | |
| 3485 _task_id, | |
| 3486 newRegion.start(), newRegion.end()); | |
| 3487 } | |
| 3488 // Now push the part of the region we didn't scan on the | |
| 3489 // region stack to make sure a task scans it later. | |
|
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|
3490 _cm->region_stack_push_with_lock(newRegion); |
| 342 | 3491 } |
| 3492 // break from while | |
| 3493 mr = MemRegion(); | |
| 3494 } | |
| 3495 _region_finger = NULL; | |
| 3496 } | |
| 3497 | |
| 3498 if (_cm->verbose_low()) | |
| 3499 gclog_or_tty->print_cr("[%d] drained region stack, size = %d", | |
| 3500 _task_id, _cm->region_stack_size()); | |
| 3501 } | |
| 3502 } | |
| 3503 | |
| 3504 void CMTask::print_stats() { | |
| 3505 gclog_or_tty->print_cr("Marking Stats, task = %d, calls = %d", | |
| 3506 _task_id, _calls); | |
| 3507 gclog_or_tty->print_cr(" Elapsed time = %1.2lfms, Termination time = %1.2lfms", | |
| 3508 _elapsed_time_ms, _termination_time_ms); | |
| 3509 gclog_or_tty->print_cr(" Step Times (cum): num = %d, avg = %1.2lfms, sd = %1.2lfms", | |
| 3510 _step_times_ms.num(), _step_times_ms.avg(), | |
| 3511 _step_times_ms.sd()); | |
| 3512 gclog_or_tty->print_cr(" max = %1.2lfms, total = %1.2lfms", | |
| 3513 _step_times_ms.maximum(), _step_times_ms.sum()); | |
| 3514 | |
| 3515 #if _MARKING_STATS_ | |
| 3516 gclog_or_tty->print_cr(" Clock Intervals (cum): num = %d, avg = %1.2lfms, sd = %1.2lfms", | |
| 3517 _all_clock_intervals_ms.num(), _all_clock_intervals_ms.avg(), | |
| 3518 _all_clock_intervals_ms.sd()); | |
| 3519 gclog_or_tty->print_cr(" max = %1.2lfms, total = %1.2lfms", | |
| 3520 _all_clock_intervals_ms.maximum(), | |
| 3521 _all_clock_intervals_ms.sum()); | |
| 3522 gclog_or_tty->print_cr(" Clock Causes (cum): scanning = %d, marking = %d", | |
| 3523 _clock_due_to_scanning, _clock_due_to_marking); | |
| 3524 gclog_or_tty->print_cr(" Objects: scanned = %d, found on the bitmap = %d", | |
| 3525 _objs_scanned, _objs_found_on_bitmap); | |
| 3526 gclog_or_tty->print_cr(" Local Queue: pushes = %d, pops = %d, max size = %d", | |
| 3527 _local_pushes, _local_pops, _local_max_size); | |
| 3528 gclog_or_tty->print_cr(" Global Stack: pushes = %d, pops = %d, max size = %d", | |
| 3529 _global_pushes, _global_pops, _global_max_size); | |
| 3530 gclog_or_tty->print_cr(" transfers to = %d, transfers from = %d", | |
| 3531 _global_transfers_to,_global_transfers_from); | |
| 3532 gclog_or_tty->print_cr(" Regions: claimed = %d, Region Stack: pops = %d", | |
| 3533 _regions_claimed, _region_stack_pops); | |
| 3534 gclog_or_tty->print_cr(" SATB buffers: processed = %d", _satb_buffers_processed); | |
| 3535 gclog_or_tty->print_cr(" Steals: attempts = %d, successes = %d", | |
| 3536 _steal_attempts, _steals); | |
| 3537 gclog_or_tty->print_cr(" Aborted: %d, due to", _aborted); | |
| 3538 gclog_or_tty->print_cr(" overflow: %d, global abort: %d, yield: %d", | |
| 3539 _aborted_overflow, _aborted_cm_aborted, _aborted_yield); | |
| 3540 gclog_or_tty->print_cr(" time out: %d, SATB: %d, termination: %d", | |
| 3541 _aborted_timed_out, _aborted_satb, _aborted_termination); | |
| 3542 #endif // _MARKING_STATS_ | |
| 3543 } | |
| 3544 | |
| 3545 /***************************************************************************** | |
| 3546 | |
| 3547 The do_marking_step(time_target_ms) method is the building block | |
| 3548 of the parallel marking framework. It can be called in parallel | |
| 3549 with other invocations of do_marking_step() on different tasks | |
| 3550 (but only one per task, obviously) and concurrently with the | |
| 3551 mutator threads, or during remark, hence it eliminates the need | |
| 3552 for two versions of the code. When called during remark, it will | |
| 3553 pick up from where the task left off during the concurrent marking | |
| 3554 phase. Interestingly, tasks are also claimable during evacuation | |
| 3555 pauses too, since do_marking_step() ensures that it aborts before | |
| 3556 it needs to yield. | |
| 3557 | |
| 3558 The data structures that is uses to do marking work are the | |
| 3559 following: | |
| 3560 | |
| 3561 (1) Marking Bitmap. If there are gray objects that appear only | |
| 3562 on the bitmap (this happens either when dealing with an overflow | |
| 3563 or when the initial marking phase has simply marked the roots | |
| 3564 and didn't push them on the stack), then tasks claim heap | |
| 3565 regions whose bitmap they then scan to find gray objects. A | |
| 3566 global finger indicates where the end of the last claimed region | |
| 3567 is. A local finger indicates how far into the region a task has | |
| 3568 scanned. The two fingers are used to determine how to gray an | |
| 3569 object (i.e. whether simply marking it is OK, as it will be | |
| 3570 visited by a task in the future, or whether it needs to be also | |
| 3571 pushed on a stack). | |
| 3572 | |
| 3573 (2) Local Queue. The local queue of the task which is accessed | |
| 3574 reasonably efficiently by the task. Other tasks can steal from | |
| 3575 it when they run out of work. Throughout the marking phase, a | |
| 3576 task attempts to keep its local queue short but not totally | |
| 3577 empty, so that entries are available for stealing by other | |
| 3578 tasks. Only when there is no more work, a task will totally | |
| 3579 drain its local queue. | |
| 3580 | |
| 3581 (3) Global Mark Stack. This handles local queue overflow. During | |
| 3582 marking only sets of entries are moved between it and the local | |
| 3583 queues, as access to it requires a mutex and more fine-grain | |
| 3584 interaction with it which might cause contention. If it | |
| 3585 overflows, then the marking phase should restart and iterate | |
| 3586 over the bitmap to identify gray objects. Throughout the marking | |
| 3587 phase, tasks attempt to keep the global mark stack at a small | |
| 3588 length but not totally empty, so that entries are available for | |
| 3589 popping by other tasks. Only when there is no more work, tasks | |
| 3590 will totally drain the global mark stack. | |
| 3591 | |
| 3592 (4) Global Region Stack. Entries on it correspond to areas of | |
| 3593 the bitmap that need to be scanned since they contain gray | |
| 3594 objects. Pushes on the region stack only happen during | |
| 3595 evacuation pauses and typically correspond to areas covered by | |
| 3596 GC LABS. If it overflows, then the marking phase should restart | |
| 3597 and iterate over the bitmap to identify gray objects. Tasks will | |
| 3598 try to totally drain the region stack as soon as possible. | |
| 3599 | |
| 3600 (5) SATB Buffer Queue. This is where completed SATB buffers are | |
| 3601 made available. Buffers are regularly removed from this queue | |
| 3602 and scanned for roots, so that the queue doesn't get too | |
| 3603 long. During remark, all completed buffers are processed, as | |
| 3604 well as the filled in parts of any uncompleted buffers. | |
| 3605 | |
| 3606 The do_marking_step() method tries to abort when the time target | |
| 3607 has been reached. There are a few other cases when the | |
| 3608 do_marking_step() method also aborts: | |
| 3609 | |
| 3610 (1) When the marking phase has been aborted (after a Full GC). | |
| 3611 | |
| 3612 (2) When a global overflow (either on the global stack or the | |
| 3613 region stack) has been triggered. Before the task aborts, it | |
| 3614 will actually sync up with the other tasks to ensure that all | |
| 3615 the marking data structures (local queues, stacks, fingers etc.) | |
| 3616 are re-initialised so that when do_marking_step() completes, | |
| 3617 the marking phase can immediately restart. | |
| 3618 | |
| 3619 (3) When enough completed SATB buffers are available. The | |
| 3620 do_marking_step() method only tries to drain SATB buffers right | |
| 3621 at the beginning. So, if enough buffers are available, the | |
| 3622 marking step aborts and the SATB buffers are processed at | |
| 3623 the beginning of the next invocation. | |
| 3624 | |
| 3625 (4) To yield. when we have to yield then we abort and yield | |
| 3626 right at the end of do_marking_step(). This saves us from a lot | |
| 3627 of hassle as, by yielding we might allow a Full GC. If this | |
| 3628 happens then objects will be compacted underneath our feet, the | |
| 3629 heap might shrink, etc. We save checking for this by just | |
| 3630 aborting and doing the yield right at the end. | |
| 3631 | |
| 3632 From the above it follows that the do_marking_step() method should | |
| 3633 be called in a loop (or, otherwise, regularly) until it completes. | |
| 3634 | |
| 3635 If a marking step completes without its has_aborted() flag being | |
| 3636 true, it means it has completed the current marking phase (and | |
| 3637 also all other marking tasks have done so and have all synced up). | |
| 3638 | |
| 3639 A method called regular_clock_call() is invoked "regularly" (in | |
| 3640 sub ms intervals) throughout marking. It is this clock method that | |
| 3641 checks all the abort conditions which were mentioned above and | |
| 3642 decides when the task should abort. A work-based scheme is used to | |
| 3643 trigger this clock method: when the number of object words the | |
| 3644 marking phase has scanned or the number of references the marking | |
| 3645 phase has visited reach a given limit. Additional invocations to | |
| 3646 the method clock have been planted in a few other strategic places | |
| 3647 too. The initial reason for the clock method was to avoid calling | |
| 3648 vtime too regularly, as it is quite expensive. So, once it was in | |
| 3649 place, it was natural to piggy-back all the other conditions on it | |
| 3650 too and not constantly check them throughout the code. | |
| 3651 | |
| 3652 *****************************************************************************/ | |
| 3653 | |
| 3654 void CMTask::do_marking_step(double time_target_ms) { | |
|
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3655 assert(time_target_ms >= 1.0, "minimum granularity is 1ms"); |
|
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3656 assert(concurrent() == _cm->concurrent(), "they should be the same"); |
|
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3657 |
|
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3658 assert(concurrent() || _cm->region_stack_empty(), |
|
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3659 "the region stack should have been cleared before remark"); |
|
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|
3660 assert(_region_finger == NULL, |
|
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|
3661 "this should be non-null only when a region is being scanned"); |
| 342 | 3662 |
| 3663 G1CollectorPolicy* g1_policy = _g1h->g1_policy(); | |
|
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3664 assert(_task_queues != NULL, "invariant"); |
|
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3665 assert(_task_queue != NULL, "invariant"); |
|
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3666 assert(_task_queues->queue(_task_id) == _task_queue, "invariant"); |
|
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3667 |
|
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3668 assert(!_claimed, |
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|
3669 "only one thread should claim this task at any one time"); |
| 342 | 3670 |
| 3671 // OK, this doesn't safeguard again all possible scenarios, as it is | |
| 3672 // possible for two threads to set the _claimed flag at the same | |
| 3673 // time. But it is only for debugging purposes anyway and it will | |
| 3674 // catch most problems. | |
| 3675 _claimed = true; | |
| 3676 | |
| 3677 _start_time_ms = os::elapsedVTime() * 1000.0; | |
| 3678 statsOnly( _interval_start_time_ms = _start_time_ms ); | |
| 3679 | |
| 3680 double diff_prediction_ms = | |
| 3681 g1_policy->get_new_prediction(&_marking_step_diffs_ms); | |
| 3682 _time_target_ms = time_target_ms - diff_prediction_ms; | |
| 3683 | |
| 3684 // set up the variables that are used in the work-based scheme to | |
| 3685 // call the regular clock method | |
| 3686 _words_scanned = 0; | |
| 3687 _refs_reached = 0; | |
| 3688 recalculate_limits(); | |
| 3689 | |
| 3690 // clear all flags | |
| 3691 clear_has_aborted(); | |
| 3692 _has_aborted_timed_out = false; | |
| 3693 _draining_satb_buffers = false; | |
| 3694 | |
| 3695 ++_calls; | |
| 3696 | |
| 3697 if (_cm->verbose_low()) | |
| 3698 gclog_or_tty->print_cr("[%d] >>>>>>>>>> START, call = %d, " | |
| 3699 "target = %1.2lfms >>>>>>>>>>", | |
| 3700 _task_id, _calls, _time_target_ms); | |
| 3701 | |
| 3702 // Set up the bitmap and oop closures. Anything that uses them is | |
| 3703 // eventually called from this method, so it is OK to allocate these | |
| 3704 // statically. | |
| 3705 CMBitMapClosure bitmap_closure(this, _cm, _nextMarkBitMap); | |
| 3706 CMOopClosure oop_closure(_g1h, _cm, this); | |
| 3707 set_oop_closure(&oop_closure); | |
| 3708 | |
| 3709 if (_cm->has_overflown()) { | |
| 3710 // This can happen if the region stack or the mark stack overflows | |
| 3711 // during a GC pause and this task, after a yield point, | |
| 3712 // restarts. We have to abort as we need to get into the overflow | |
| 3713 // protocol which happens right at the end of this task. | |
| 3714 set_has_aborted(); | |
| 3715 } | |
| 3716 | |
| 3717 // First drain any available SATB buffers. After this, we will not | |
| 3718 // look at SATB buffers before the next invocation of this method. | |
| 3719 // If enough completed SATB buffers are queued up, the regular clock | |
| 3720 // will abort this task so that it restarts. | |
| 3721 drain_satb_buffers(); | |
| 3722 // ...then partially drain the local queue and the global stack | |
| 3723 drain_local_queue(true); | |
| 3724 drain_global_stack(true); | |
| 3725 | |
| 3726 // Then totally drain the region stack. We will not look at | |
| 3727 // it again before the next invocation of this method. Entries on | |
| 3728 // the region stack are only added during evacuation pauses, for | |
| 3729 // which we have to yield. When we do, we abort the task anyway so | |
| 3730 // it will look at the region stack again when it restarts. | |
| 3731 bitmap_closure.set_scanning_heap_region(false); | |
| 3732 drain_region_stack(&bitmap_closure); | |
| 3733 // ...then partially drain the local queue and the global stack | |
| 3734 drain_local_queue(true); | |
| 3735 drain_global_stack(true); | |
| 3736 | |
| 3737 do { | |
| 3738 if (!has_aborted() && _curr_region != NULL) { | |
| 3739 // This means that we're already holding on to a region. | |
|
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3740 assert(_finger != NULL, "if region is not NULL, then the finger " |
|
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|
3741 "should not be NULL either"); |
| 342 | 3742 |
| 3743 // We might have restarted this task after an evacuation pause | |
| 3744 // which might have evacuated the region we're holding on to | |
| 3745 // underneath our feet. Let's read its limit again to make sure | |
| 3746 // that we do not iterate over a region of the heap that | |
| 3747 // contains garbage (update_region_limit() will also move | |
| 3748 // _finger to the start of the region if it is found empty). | |
| 3749 update_region_limit(); | |
| 3750 // We will start from _finger not from the start of the region, | |
| 3751 // as we might be restarting this task after aborting half-way | |
| 3752 // through scanning this region. In this case, _finger points to | |
| 3753 // the address where we last found a marked object. If this is a | |
| 3754 // fresh region, _finger points to start(). | |
| 3755 MemRegion mr = MemRegion(_finger, _region_limit); | |
| 3756 | |
| 3757 if (_cm->verbose_low()) | |
| 3758 gclog_or_tty->print_cr("[%d] we're scanning part " | |
| 3759 "["PTR_FORMAT", "PTR_FORMAT") " | |
| 3760 "of region "PTR_FORMAT, | |
| 3761 _task_id, _finger, _region_limit, _curr_region); | |
| 3762 | |
| 3763 // Let's iterate over the bitmap of the part of the | |
| 3764 // region that is left. | |
| 3765 bitmap_closure.set_scanning_heap_region(true); | |
| 3766 if (mr.is_empty() || | |
| 3767 _nextMarkBitMap->iterate(&bitmap_closure, mr)) { | |
| 3768 // We successfully completed iterating over the region. Now, | |
| 3769 // let's give up the region. | |
| 3770 giveup_current_region(); | |
| 3771 regular_clock_call(); | |
| 3772 } else { | |
|
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|
3773 assert(has_aborted(), "currently the only way to do so"); |
| 342 | 3774 // The only way to abort the bitmap iteration is to return |
| 3775 // false from the do_bit() method. However, inside the | |
| 3776 // do_bit() method we move the _finger to point to the | |
| 3777 // object currently being looked at. So, if we bail out, we | |
| 3778 // have definitely set _finger to something non-null. | |
|
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|
3779 assert(_finger != NULL, "invariant"); |
| 342 | 3780 |
| 3781 // Region iteration was actually aborted. So now _finger | |
| 3782 // points to the address of the object we last scanned. If we | |
| 3783 // leave it there, when we restart this task, we will rescan | |
| 3784 // the object. It is easy to avoid this. We move the finger by | |
| 3785 // enough to point to the next possible object header (the | |
| 3786 // bitmap knows by how much we need to move it as it knows its | |
| 3787 // granularity). | |
|
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|
3788 assert(_finger < _region_limit, "invariant"); |
|
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|
3789 HeapWord* new_finger = _nextMarkBitMap->nextWord(_finger); |
|
3f0549ed0c98
6921710: G1: assert(new_finger >= _finger && new_finger < _region_limit,"invariant")
apetrusenko
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|
3790 // Check if bitmap iteration was aborted while scanning the last object |
|
3f0549ed0c98
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apetrusenko
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|
3791 if (new_finger >= _region_limit) { |
|
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|
3792 giveup_current_region(); |
|
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apetrusenko
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|
3793 } else { |
|
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|
3794 move_finger_to(new_finger); |
|
3f0549ed0c98
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|
3795 } |
| 342 | 3796 } |
| 3797 } | |
| 3798 // At this point we have either completed iterating over the | |
| 3799 // region we were holding on to, or we have aborted. | |
| 3800 | |
| 3801 // We then partially drain the local queue and the global stack. | |
| 3802 // (Do we really need this?) | |
| 3803 drain_local_queue(true); | |
| 3804 drain_global_stack(true); | |
| 3805 | |
| 3806 // Read the note on the claim_region() method on why it might | |
| 3807 // return NULL with potentially more regions available for | |
| 3808 // claiming and why we have to check out_of_regions() to determine | |
| 3809 // whether we're done or not. | |
| 3810 while (!has_aborted() && _curr_region == NULL && !_cm->out_of_regions()) { | |
| 3811 // We are going to try to claim a new region. We should have | |
| 3812 // given up on the previous one. | |
|
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3813 // Separated the asserts so that we know which one fires. |
|
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|
3814 assert(_curr_region == NULL, "invariant"); |
|
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|
3815 assert(_finger == NULL, "invariant"); |
|
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|
3816 assert(_region_limit == NULL, "invariant"); |
| 342 | 3817 if (_cm->verbose_low()) |
| 3818 gclog_or_tty->print_cr("[%d] trying to claim a new region", _task_id); | |
| 3819 HeapRegion* claimed_region = _cm->claim_region(_task_id); | |
| 3820 if (claimed_region != NULL) { | |
| 3821 // Yes, we managed to claim one | |
| 3822 statsOnly( ++_regions_claimed ); | |
| 3823 | |
| 3824 if (_cm->verbose_low()) | |
| 3825 gclog_or_tty->print_cr("[%d] we successfully claimed " | |
| 3826 "region "PTR_FORMAT, | |
| 3827 _task_id, claimed_region); | |
| 3828 | |
| 3829 setup_for_region(claimed_region); | |
|
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|
3830 assert(_curr_region == claimed_region, "invariant"); |
| 342 | 3831 } |
| 3832 // It is important to call the regular clock here. It might take | |
| 3833 // a while to claim a region if, for example, we hit a large | |
| 3834 // block of empty regions. So we need to call the regular clock | |
| 3835 // method once round the loop to make sure it's called | |
| 3836 // frequently enough. | |
| 3837 regular_clock_call(); | |
| 3838 } | |
| 3839 | |
| 3840 if (!has_aborted() && _curr_region == NULL) { | |
|
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3841 assert(_cm->out_of_regions(), |
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3842 "at this point we should be out of regions"); |
| 342 | 3843 } |
| 3844 } while ( _curr_region != NULL && !has_aborted()); | |
| 3845 | |
| 3846 if (!has_aborted()) { | |
| 3847 // We cannot check whether the global stack is empty, since other | |
|
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3848 // tasks might be pushing objects to it concurrently. We also cannot |
|
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3849 // check if the region stack is empty because if a thread is aborting |
|
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3850 // it can push a partially done region back. |
|
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3851 assert(_cm->out_of_regions(), |
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3852 "at this point we should be out of regions"); |
| 342 | 3853 |
| 3854 if (_cm->verbose_low()) | |
| 3855 gclog_or_tty->print_cr("[%d] all regions claimed", _task_id); | |
| 3856 | |
| 3857 // Try to reduce the number of available SATB buffers so that | |
| 3858 // remark has less work to do. | |
| 3859 drain_satb_buffers(); | |
| 3860 } | |
| 3861 | |
| 3862 // Since we've done everything else, we can now totally drain the | |
| 3863 // local queue and global stack. | |
| 3864 drain_local_queue(false); | |
| 3865 drain_global_stack(false); | |
| 3866 | |
| 3867 // Attempt at work stealing from other task's queues. | |
| 3868 if (!has_aborted()) { | |
| 3869 // We have not aborted. This means that we have finished all that | |
| 3870 // we could. Let's try to do some stealing... | |
| 3871 | |
| 3872 // We cannot check whether the global stack is empty, since other | |
|
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3873 // tasks might be pushing objects to it concurrently. We also cannot |
|
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3874 // check if the region stack is empty because if a thread is aborting |
|
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3875 // it can push a partially done region back. |
|
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3876 assert(_cm->out_of_regions() && _task_queue->size() == 0, |
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3877 "only way to reach here"); |
| 342 | 3878 |
| 3879 if (_cm->verbose_low()) | |
| 3880 gclog_or_tty->print_cr("[%d] starting to steal", _task_id); | |
| 3881 | |
| 3882 while (!has_aborted()) { | |
| 3883 oop obj; | |
| 3884 statsOnly( ++_steal_attempts ); | |
| 3885 | |
| 3886 if (_cm->try_stealing(_task_id, &_hash_seed, obj)) { | |
| 3887 if (_cm->verbose_medium()) | |
| 3888 gclog_or_tty->print_cr("[%d] stolen "PTR_FORMAT" successfully", | |
| 3889 _task_id, (void*) obj); | |
| 3890 | |
| 3891 statsOnly( ++_steals ); | |
| 3892 | |
|
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3893 assert(_nextMarkBitMap->isMarked((HeapWord*) obj), |
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|
3894 "any stolen object should be marked"); |
| 342 | 3895 scan_object(obj); |
| 3896 | |
| 3897 // And since we're towards the end, let's totally drain the | |
| 3898 // local queue and global stack. | |
| 3899 drain_local_queue(false); | |
| 3900 drain_global_stack(false); | |
| 3901 } else { | |
| 3902 break; | |
| 3903 } | |
| 3904 } | |
| 3905 } | |
| 3906 | |
| 3907 // We still haven't aborted. Now, let's try to get into the | |
| 3908 // termination protocol. | |
| 3909 if (!has_aborted()) { | |
| 3910 // We cannot check whether the global stack is empty, since other | |
|
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3911 // tasks might be concurrently pushing objects on it. We also cannot |
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3912 // check if the region stack is empty because if a thread is aborting |
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3913 // it can push a partially done region back. |
|
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3914 // Separated the asserts so that we know which one fires. |
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3915 assert(_cm->out_of_regions(), "only way to reach here"); |
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3916 assert(_task_queue->size() == 0, "only way to reach here"); |
| 342 | 3917 |
| 3918 if (_cm->verbose_low()) | |
| 3919 gclog_or_tty->print_cr("[%d] starting termination protocol", _task_id); | |
| 3920 | |
| 3921 _termination_start_time_ms = os::elapsedVTime() * 1000.0; | |
| 3922 // The CMTask class also extends the TerminatorTerminator class, | |
| 3923 // hence its should_exit_termination() method will also decide | |
| 3924 // whether to exit the termination protocol or not. | |
| 3925 bool finished = _cm->terminator()->offer_termination(this); | |
| 3926 double termination_end_time_ms = os::elapsedVTime() * 1000.0; | |
| 3927 _termination_time_ms += | |
| 3928 termination_end_time_ms - _termination_start_time_ms; | |
| 3929 | |
| 3930 if (finished) { | |
| 3931 // We're all done. | |
| 3932 | |
| 3933 if (_task_id == 0) { | |
| 3934 // let's allow task 0 to do this | |
| 3935 if (concurrent()) { | |
|
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3936 assert(_cm->concurrent_marking_in_progress(), "invariant"); |
| 342 | 3937 // we need to set this to false before the next |
| 3938 // safepoint. This way we ensure that the marking phase | |
| 3939 // doesn't observe any more heap expansions. | |
| 3940 _cm->clear_concurrent_marking_in_progress(); | |
| 3941 } | |
| 3942 } | |
| 3943 | |
| 3944 // We can now guarantee that the global stack is empty, since | |
|
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3945 // all other tasks have finished. We separated the guarantees so |
|
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3946 // that, if a condition is false, we can immediately find out |
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3947 // which one. |
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|
3948 guarantee(_cm->out_of_regions(), "only way to reach here"); |
|
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|
3949 guarantee(_cm->region_stack_empty(), "only way to reach here"); |
|
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|
3950 guarantee(_cm->mark_stack_empty(), "only way to reach here"); |
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|
3951 guarantee(_task_queue->size() == 0, "only way to reach here"); |
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|
3952 guarantee(!_cm->has_overflown(), "only way to reach here"); |
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3953 guarantee(!_cm->mark_stack_overflow(), "only way to reach here"); |
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|
3954 guarantee(!_cm->region_stack_overflow(), "only way to reach here"); |
| 342 | 3955 |
| 3956 if (_cm->verbose_low()) | |
| 3957 gclog_or_tty->print_cr("[%d] all tasks terminated", _task_id); | |
| 3958 } else { | |
| 3959 // Apparently there's more work to do. Let's abort this task. It | |
| 3960 // will restart it and we can hopefully find more things to do. | |
| 3961 | |
| 3962 if (_cm->verbose_low()) | |
| 3963 gclog_or_tty->print_cr("[%d] apparently there is more work to do", _task_id); | |
| 3964 | |
| 3965 set_has_aborted(); | |
| 3966 statsOnly( ++_aborted_termination ); | |
| 3967 } | |
| 3968 } | |
| 3969 | |
| 3970 // Mainly for debugging purposes to make sure that a pointer to the | |
| 3971 // closure which was statically allocated in this frame doesn't | |
| 3972 // escape it by accident. | |
| 3973 set_oop_closure(NULL); | |
| 3974 double end_time_ms = os::elapsedVTime() * 1000.0; | |
| 3975 double elapsed_time_ms = end_time_ms - _start_time_ms; | |
| 3976 // Update the step history. | |
| 3977 _step_times_ms.add(elapsed_time_ms); | |
| 3978 | |
| 3979 if (has_aborted()) { | |
| 3980 // The task was aborted for some reason. | |
| 3981 | |
| 3982 statsOnly( ++_aborted ); | |
| 3983 | |
| 3984 if (_has_aborted_timed_out) { | |
| 3985 double diff_ms = elapsed_time_ms - _time_target_ms; | |
| 3986 // Keep statistics of how well we did with respect to hitting | |
| 3987 // our target only if we actually timed out (if we aborted for | |
| 3988 // other reasons, then the results might get skewed). | |
| 3989 _marking_step_diffs_ms.add(diff_ms); | |
| 3990 } | |
| 3991 | |
| 3992 if (_cm->has_overflown()) { | |
| 3993 // This is the interesting one. We aborted because a global | |
| 3994 // overflow was raised. This means we have to restart the | |
| 3995 // marking phase and start iterating over regions. However, in | |
| 3996 // order to do this we have to make sure that all tasks stop | |
| 3997 // what they are doing and re-initialise in a safe manner. We | |
| 3998 // will achieve this with the use of two barrier sync points. | |
| 3999 | |
| 4000 if (_cm->verbose_low()) | |
| 4001 gclog_or_tty->print_cr("[%d] detected overflow", _task_id); | |
| 4002 | |
| 4003 _cm->enter_first_sync_barrier(_task_id); | |
| 4004 // When we exit this sync barrier we know that all tasks have | |
| 4005 // stopped doing marking work. So, it's now safe to | |
| 4006 // re-initialise our data structures. At the end of this method, | |
| 4007 // task 0 will clear the global data structures. | |
| 4008 | |
| 4009 statsOnly( ++_aborted_overflow ); | |
| 4010 | |
| 4011 // We clear the local state of this task... | |
| 4012 clear_region_fields(); | |
| 4013 | |
| 4014 // ...and enter the second barrier. | |
| 4015 _cm->enter_second_sync_barrier(_task_id); | |
| 4016 // At this point everything has bee re-initialised and we're | |
| 4017 // ready to restart. | |
| 4018 } | |
| 4019 | |
| 4020 if (_cm->verbose_low()) { | |
| 4021 gclog_or_tty->print_cr("[%d] <<<<<<<<<< ABORTING, target = %1.2lfms, " | |
| 4022 "elapsed = %1.2lfms <<<<<<<<<<", | |
| 4023 _task_id, _time_target_ms, elapsed_time_ms); | |
| 4024 if (_cm->has_aborted()) | |
| 4025 gclog_or_tty->print_cr("[%d] ========== MARKING ABORTED ==========", | |
| 4026 _task_id); | |
| 4027 } | |
| 4028 } else { | |
| 4029 if (_cm->verbose_low()) | |
| 4030 gclog_or_tty->print_cr("[%d] <<<<<<<<<< FINISHED, target = %1.2lfms, " | |
| 4031 "elapsed = %1.2lfms <<<<<<<<<<", | |
| 4032 _task_id, _time_target_ms, elapsed_time_ms); | |
| 4033 } | |
| 4034 | |
| 4035 _claimed = false; | |
| 4036 } | |
| 4037 | |
| 4038 CMTask::CMTask(int task_id, | |
| 4039 ConcurrentMark* cm, | |
| 4040 CMTaskQueue* task_queue, | |
| 4041 CMTaskQueueSet* task_queues) | |
| 4042 : _g1h(G1CollectedHeap::heap()), | |
| 4043 _task_id(task_id), _cm(cm), | |
| 4044 _claimed(false), | |
| 4045 _nextMarkBitMap(NULL), _hash_seed(17), | |
| 4046 _task_queue(task_queue), | |
| 4047 _task_queues(task_queues), | |
| 4048 _oop_closure(NULL) { | |
|
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4049 guarantee(task_queue != NULL, "invariant"); |
|
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|
4050 guarantee(task_queues != NULL, "invariant"); |
| 342 | 4051 |
| 4052 statsOnly( _clock_due_to_scanning = 0; | |
| 4053 _clock_due_to_marking = 0 ); | |
| 4054 | |
| 4055 _marking_step_diffs_ms.add(0.5); | |
| 4056 } |