rev 57223 : imported patch 8225484-changes-to-survivor-calculation
1 /* 2 * Copyright (c) 2014, 2019, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "gc/g1/g1Allocator.inline.hpp" 27 #include "gc/g1/g1CollectedHeap.inline.hpp" 28 #include "gc/g1/g1CollectionSet.hpp" 29 #include "gc/g1/g1OopClosures.inline.hpp" 30 #include "gc/g1/g1ParScanThreadState.inline.hpp" 31 #include "gc/g1/g1RootClosures.hpp" 32 #include "gc/g1/g1StringDedup.hpp" 33 #include "gc/g1/g1Trace.hpp" 34 #include "gc/shared/taskqueue.inline.hpp" 35 #include "memory/allocation.inline.hpp" 36 #include "oops/access.inline.hpp" 37 #include "oops/oop.inline.hpp" 38 #include "runtime/prefetch.inline.hpp" 39 40 G1ParScanThreadState::G1ParScanThreadState(G1CollectedHeap* g1h, 41 G1RedirtyCardsQueueSet* rdcqs, 42 uint worker_id, 43 size_t young_cset_length, 44 size_t optional_cset_length) 45 : _g1h(g1h), 46 _refs(g1h->task_queue(worker_id)), 47 _rdcq(rdcqs), 48 _ct(g1h->card_table()), 49 _closures(NULL), 50 _plab_allocator(NULL), 51 _age_table(false), 52 _tenuring_threshold(g1h->policy()->tenuring_threshold()), 53 _scanner(g1h, this), 54 _worker_id(worker_id), 55 _last_enqueued_card(SIZE_MAX), 56 _stack_trim_upper_threshold(GCDrainStackTargetSize * 2 + 1), 57 _stack_trim_lower_threshold(GCDrainStackTargetSize), 58 _trim_ticks(), 59 _surviving_survivor_words(0), 60 _surviving_young_words_base(NULL), 61 _surviving_young_words(NULL), 62 _surviving_words_length(young_cset_length + 1), 63 _old_gen_is_full(false), 64 _num_optional_regions(optional_cset_length), 65 _numa(g1h->numa()), 66 _obj_alloc_stat(NULL) 67 { 68 // We allocate number of young gen regions in the collection set plus one 69 // entries, since entry 0 keeps track of surviving bytes for non-young regions. 70 // We also add a few elements at the beginning and at the end in 71 // an attempt to eliminate cache contention 72 size_t array_length = PADDING_ELEM_NUM + _surviving_words_length + PADDING_ELEM_NUM; 73 _surviving_young_words_base = NEW_C_HEAP_ARRAY(size_t, array_length, mtGC); 74 _surviving_young_words = _surviving_young_words_base + PADDING_ELEM_NUM; 75 memset(_surviving_young_words, 0, _surviving_words_length * sizeof(size_t)); 76 77 _plab_allocator = new G1PLABAllocator(_g1h->allocator()); 78 79 // The dest for Young is used when the objects are aged enough to 80 // need to be moved to the next space. 81 _dest[G1HeapRegionAttr::Young] = G1HeapRegionAttr::Old; 82 _dest[G1HeapRegionAttr::Old] = G1HeapRegionAttr::Old; 83 84 _closures = G1EvacuationRootClosures::create_root_closures(this, _g1h); 85 86 _oops_into_optional_regions = new G1OopStarChunkedList[_num_optional_regions]; 87 88 initialize_numa_stats(); 89 } 90 91 size_t G1ParScanThreadState::flush(size_t* surviving_young_words) { 92 _rdcq.flush(); 93 flush_numa_stats(); 94 // Update allocation statistics. 95 _plab_allocator->flush_and_retire_stats(); 96 _g1h->policy()->record_age_table(&_age_table); 97 _g1h->policy()->record_surviving_survivor_words(_surviving_survivor_words); 98 99 size_t sum = 0; 100 for (uint i = 0; i < _surviving_words_length; i++) { 101 surviving_young_words[i] += _surviving_young_words[i]; 102 sum += _surviving_young_words[i]; 103 } 104 return sum; 105 } 106 107 G1ParScanThreadState::~G1ParScanThreadState() { 108 delete _plab_allocator; 109 delete _closures; 110 FREE_C_HEAP_ARRAY(size_t, _surviving_young_words_base); 111 delete[] _oops_into_optional_regions; 112 FREE_C_HEAP_ARRAY(size_t, _obj_alloc_stat); 113 } 114 115 size_t G1ParScanThreadState::lab_waste_words() const { 116 return _plab_allocator->waste(); 117 } 118 119 size_t G1ParScanThreadState::lab_undo_waste_words() const { 120 return _plab_allocator->undo_waste(); 121 } 122 123 #ifdef ASSERT 124 bool G1ParScanThreadState::verify_ref(narrowOop* ref) const { 125 assert(ref != NULL, "invariant"); 126 assert(UseCompressedOops, "sanity"); 127 assert(!has_partial_array_mask(ref), "ref=" PTR_FORMAT, p2i(ref)); 128 oop p = RawAccess<>::oop_load(ref); 129 assert(_g1h->is_in_g1_reserved(p), 130 "ref=" PTR_FORMAT " p=" PTR_FORMAT, p2i(ref), p2i(p)); 131 return true; 132 } 133 134 bool G1ParScanThreadState::verify_ref(oop* ref) const { 135 assert(ref != NULL, "invariant"); 136 if (has_partial_array_mask(ref)) { 137 // Must be in the collection set--it's already been copied. 138 oop p = clear_partial_array_mask(ref); 139 assert(_g1h->is_in_cset(p), 140 "ref=" PTR_FORMAT " p=" PTR_FORMAT, p2i(ref), p2i(p)); 141 } else { 142 oop p = RawAccess<>::oop_load(ref); 143 assert(_g1h->is_in_g1_reserved(p), 144 "ref=" PTR_FORMAT " p=" PTR_FORMAT, p2i(ref), p2i(p)); 145 } 146 return true; 147 } 148 149 bool G1ParScanThreadState::verify_task(StarTask ref) const { 150 if (ref.is_narrow()) { 151 return verify_ref((narrowOop*) ref); 152 } else { 153 return verify_ref((oop*) ref); 154 } 155 } 156 #endif // ASSERT 157 158 void G1ParScanThreadState::trim_queue() { 159 StarTask ref; 160 do { 161 // Fully drain the queue. 162 trim_queue_to_threshold(0); 163 } while (!_refs->is_empty()); 164 } 165 166 HeapWord* G1ParScanThreadState::allocate_in_next_plab(G1HeapRegionAttr* dest, 167 size_t word_sz, 168 bool previous_plab_refill_failed, 169 uint node_index) { 170 171 assert(dest->is_in_cset_or_humongous(), "Unexpected dest: %s region attr", dest->get_type_str()); 172 173 // Right now we only have two types of regions (young / old) so 174 // let's keep the logic here simple. We can generalize it when necessary. 175 if (dest->is_young()) { 176 bool plab_refill_in_old_failed = false; 177 HeapWord* const obj_ptr = _plab_allocator->allocate(G1HeapRegionAttr::Old, 178 word_sz, 179 &plab_refill_in_old_failed, 180 node_index); 181 // Make sure that we won't attempt to copy any other objects out 182 // of a survivor region (given that apparently we cannot allocate 183 // any new ones) to avoid coming into this slow path again and again. 184 // Only consider failed PLAB refill here: failed inline allocations are 185 // typically large, so not indicative of remaining space. 186 if (previous_plab_refill_failed) { 187 _tenuring_threshold = 0; 188 } 189 190 if (obj_ptr != NULL) { 191 dest->set_old(); 192 } else { 193 // We just failed to allocate in old gen. The same idea as explained above 194 // for making survivor gen unavailable for allocation applies for old gen. 195 _old_gen_is_full = plab_refill_in_old_failed; 196 } 197 return obj_ptr; 198 } else { 199 _old_gen_is_full = previous_plab_refill_failed; 200 assert(dest->is_old(), "Unexpected dest region attr: %s", dest->get_type_str()); 201 // no other space to try. 202 return NULL; 203 } 204 } 205 206 G1HeapRegionAttr G1ParScanThreadState::next_region_attr(G1HeapRegionAttr const region_attr, markWord const m, uint& age) { 207 if (region_attr.is_young()) { 208 age = !m.has_displaced_mark_helper() ? m.age() 209 : m.displaced_mark_helper().age(); 210 if (age < _tenuring_threshold) { 211 return region_attr; 212 } 213 } 214 return dest(region_attr); 215 } 216 217 void G1ParScanThreadState::report_promotion_event(G1HeapRegionAttr const dest_attr, 218 oop const old, size_t word_sz, uint age, 219 HeapWord * const obj_ptr, uint node_index) const { 220 PLAB* alloc_buf = _plab_allocator->alloc_buffer(dest_attr, node_index); 221 if (alloc_buf->contains(obj_ptr)) { 222 _g1h->_gc_tracer_stw->report_promotion_in_new_plab_event(old->klass(), word_sz * HeapWordSize, age, 223 dest_attr.type() == G1HeapRegionAttr::Old, 224 alloc_buf->word_sz() * HeapWordSize); 225 } else { 226 _g1h->_gc_tracer_stw->report_promotion_outside_plab_event(old->klass(), word_sz * HeapWordSize, age, 227 dest_attr.type() == G1HeapRegionAttr::Old); 228 } 229 } 230 231 oop G1ParScanThreadState::copy_to_survivor_space(G1HeapRegionAttr const region_attr, 232 oop const old, 233 markWord const old_mark) { 234 const size_t word_sz = old->size(); 235 236 uint age = 0; 237 G1HeapRegionAttr dest_attr = next_region_attr(region_attr, old_mark, age); 238 // The second clause is to prevent premature evacuation failure in case there 239 // is still space in survivor, but old gen is full. 240 if (_old_gen_is_full && dest_attr.is_old()) { 241 return handle_evacuation_failure_par(old, old_mark); 242 } 243 HeapRegion* const from_region = _g1h->heap_region_containing(old); 244 uint node_index = from_region->node_index(); 245 246 HeapWord* obj_ptr = _plab_allocator->plab_allocate(dest_attr, word_sz, node_index); 247 248 // PLAB allocations should succeed most of the time, so we'll 249 // normally check against NULL once and that's it. 250 if (obj_ptr == NULL) { 251 bool plab_refill_failed = false; 252 obj_ptr = _plab_allocator->allocate_direct_or_new_plab(dest_attr, word_sz, &plab_refill_failed, node_index); 253 if (obj_ptr == NULL) { 254 assert(region_attr.is_in_cset(), "Unexpected region attr type: %s", region_attr.get_type_str()); 255 obj_ptr = allocate_in_next_plab(&dest_attr, word_sz, plab_refill_failed, node_index); 256 if (obj_ptr == NULL) { 257 // This will either forward-to-self, or detect that someone else has 258 // installed a forwarding pointer. 259 return handle_evacuation_failure_par(old, old_mark); 260 } 261 } 262 update_numa_stats(node_index); 263 264 if (_g1h->_gc_tracer_stw->should_report_promotion_events()) { 265 // The events are checked individually as part of the actual commit 266 report_promotion_event(dest_attr, old, word_sz, age, obj_ptr, node_index); 267 } 268 } 269 270 assert(obj_ptr != NULL, "when we get here, allocation should have succeeded"); 271 assert(_g1h->is_in_reserved(obj_ptr), "Allocated memory should be in the heap"); 272 273 #ifndef PRODUCT 274 // Should this evacuation fail? 275 if (_g1h->evacuation_should_fail()) { 276 // Doing this after all the allocation attempts also tests the 277 // undo_allocation() method too. 278 _plab_allocator->undo_allocation(dest_attr, obj_ptr, word_sz, node_index); 279 return handle_evacuation_failure_par(old, old_mark); 280 } 281 #endif // !PRODUCT 282 283 // We're going to allocate linearly, so might as well prefetch ahead. 284 Prefetch::write(obj_ptr, PrefetchCopyIntervalInBytes); 285 286 const oop obj = oop(obj_ptr); 287 const oop forward_ptr = old->forward_to_atomic(obj, old_mark, memory_order_relaxed); 288 if (forward_ptr == NULL) { 289 Copy::aligned_disjoint_words((HeapWord*) old, obj_ptr, word_sz); 290 291 const uint young_index = from_region->young_index_in_cset(); 292 293 assert(from_region->is_young() || 294 (!from_region->is_young() && young_index == 0), "region %u %s index %u", from_region->hrm_index(), from_region->get_short_type_str(), young_index); 295 296 if (age > 0 && region_attr.is_young()) { 297 _surviving_survivor_words += word_sz; 298 } 299 300 if (dest_attr.is_young()) { 301 if (age < markWord::max_age) { 302 age++; 303 } 304 if (old_mark.has_displaced_mark_helper()) { 305 // In this case, we have to install the mark word first, 306 // otherwise obj looks to be forwarded (the old mark word, 307 // which contains the forward pointer, was copied) 308 obj->set_mark_raw(old_mark); 309 markWord new_mark = old_mark.displaced_mark_helper().set_age(age); 310 old_mark.set_displaced_mark_helper(new_mark); 311 } else { 312 obj->set_mark_raw(old_mark.set_age(age)); 313 } 314 _age_table.add(age, word_sz); 315 } else { 316 obj->set_mark_raw(old_mark); 317 } 318 319 if (G1StringDedup::is_enabled()) { 320 const bool is_from_young = region_attr.is_young(); 321 const bool is_to_young = dest_attr.is_young(); 322 assert(is_from_young == from_region->is_young(), 323 "sanity"); 324 assert(is_to_young == _g1h->heap_region_containing(obj)->is_young(), 325 "sanity"); 326 G1StringDedup::enqueue_from_evacuation(is_from_young, 327 is_to_young, 328 _worker_id, 329 obj); 330 } 331 332 _surviving_young_words[young_index] += word_sz; 333 334 if (obj->is_objArray() && arrayOop(obj)->length() >= ParGCArrayScanChunk) { 335 // We keep track of the next start index in the length field of 336 // the to-space object. The actual length can be found in the 337 // length field of the from-space object. 338 arrayOop(obj)->set_length(0); 339 oop* old_p = set_partial_array_mask(old); 340 do_oop_partial_array(old_p); 341 } else { 342 G1ScanInYoungSetter x(&_scanner, dest_attr.is_young()); 343 obj->oop_iterate_backwards(&_scanner); 344 } 345 return obj; 346 } else { 347 _plab_allocator->undo_allocation(dest_attr, obj_ptr, word_sz, node_index); 348 return forward_ptr; 349 } 350 } 351 352 G1ParScanThreadState* G1ParScanThreadStateSet::state_for_worker(uint worker_id) { 353 assert(worker_id < _n_workers, "out of bounds access"); 354 if (_states[worker_id] == NULL) { 355 _states[worker_id] = 356 new G1ParScanThreadState(_g1h, _rdcqs, worker_id, _young_cset_length, _optional_cset_length); 357 } 358 return _states[worker_id]; 359 } 360 361 const size_t* G1ParScanThreadStateSet::surviving_young_words() const { 362 assert(_flushed, "thread local state from the per thread states should have been flushed"); 363 return _surviving_young_words_total; 364 } 365 366 void G1ParScanThreadStateSet::flush() { 367 assert(!_flushed, "thread local state from the per thread states should be flushed once"); 368 369 for (uint worker_id = 0; worker_id < _n_workers; ++worker_id) { 370 G1ParScanThreadState* pss = _states[worker_id]; 371 372 if (pss == NULL) { 373 continue; 374 } 375 376 G1GCPhaseTimes* p = _g1h->phase_times(); 377 378 // Need to get the following two before the call to G1ParThreadScanState::flush() 379 // because it resets the PLAB allocator where we get this info from. 380 size_t lab_waste_bytes = pss->lab_waste_words() * HeapWordSize; 381 size_t lab_undo_waste_bytes = pss->lab_undo_waste_words() * HeapWordSize; 382 size_t copied_bytes = pss->flush(_surviving_young_words_total) * HeapWordSize; 383 384 p->record_or_add_thread_work_item(G1GCPhaseTimes::MergePSS, worker_id, copied_bytes, G1GCPhaseTimes::MergePSSCopiedBytes); 385 p->record_or_add_thread_work_item(G1GCPhaseTimes::MergePSS, worker_id, lab_waste_bytes, G1GCPhaseTimes::MergePSSLABWasteBytes); 386 p->record_or_add_thread_work_item(G1GCPhaseTimes::MergePSS, worker_id, lab_undo_waste_bytes, G1GCPhaseTimes::MergePSSLABUndoWasteBytes); 387 388 delete pss; 389 _states[worker_id] = NULL; 390 } 391 _flushed = true; 392 } 393 394 void G1ParScanThreadStateSet::record_unused_optional_region(HeapRegion* hr) { 395 for (uint worker_index = 0; worker_index < _n_workers; ++worker_index) { 396 G1ParScanThreadState* pss = _states[worker_index]; 397 398 if (pss == NULL) { 399 continue; 400 } 401 402 size_t used_memory = pss->oops_into_optional_region(hr)->used_memory(); 403 _g1h->phase_times()->record_or_add_thread_work_item(G1GCPhaseTimes::OptScanHR, worker_index, used_memory, G1GCPhaseTimes::ScanHRUsedMemory); 404 } 405 } 406 407 oop G1ParScanThreadState::handle_evacuation_failure_par(oop old, markWord m) { 408 assert(_g1h->is_in_cset(old), "Object " PTR_FORMAT " should be in the CSet", p2i(old)); 409 410 oop forward_ptr = old->forward_to_atomic(old, m, memory_order_relaxed); 411 if (forward_ptr == NULL) { 412 // Forward-to-self succeeded. We are the "owner" of the object. 413 HeapRegion* r = _g1h->heap_region_containing(old); 414 415 if (!r->evacuation_failed()) { 416 r->set_evacuation_failed(true); 417 _g1h->hr_printer()->evac_failure(r); 418 } 419 420 _g1h->preserve_mark_during_evac_failure(_worker_id, old, m); 421 422 G1ScanInYoungSetter x(&_scanner, r->is_young()); 423 old->oop_iterate_backwards(&_scanner); 424 425 return old; 426 } else { 427 // Forward-to-self failed. Either someone else managed to allocate 428 // space for this object (old != forward_ptr) or they beat us in 429 // self-forwarding it (old == forward_ptr). 430 assert(old == forward_ptr || !_g1h->is_in_cset(forward_ptr), 431 "Object " PTR_FORMAT " forwarded to: " PTR_FORMAT " " 432 "should not be in the CSet", 433 p2i(old), p2i(forward_ptr)); 434 return forward_ptr; 435 } 436 } 437 G1ParScanThreadStateSet::G1ParScanThreadStateSet(G1CollectedHeap* g1h, 438 G1RedirtyCardsQueueSet* rdcqs, 439 uint n_workers, 440 size_t young_cset_length, 441 size_t optional_cset_length) : 442 _g1h(g1h), 443 _rdcqs(rdcqs), 444 _states(NEW_C_HEAP_ARRAY(G1ParScanThreadState*, n_workers, mtGC)), 445 _surviving_young_words_total(NEW_C_HEAP_ARRAY(size_t, young_cset_length + 1, mtGC)), 446 _young_cset_length(young_cset_length), 447 _optional_cset_length(optional_cset_length), 448 _n_workers(n_workers), 449 _flushed(false) { 450 for (uint i = 0; i < n_workers; ++i) { 451 _states[i] = NULL; 452 } 453 memset(_surviving_young_words_total, 0, (young_cset_length + 1) * sizeof(size_t)); 454 } 455 456 G1ParScanThreadStateSet::~G1ParScanThreadStateSet() { 457 assert(_flushed, "thread local state from the per thread states should have been flushed"); 458 FREE_C_HEAP_ARRAY(G1ParScanThreadState*, _states); 459 FREE_C_HEAP_ARRAY(size_t, _surviving_young_words_total); 460 } --- EOF ---