1 /* 2 * Copyright (c) 2002, 2020, 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 "classfile/javaClasses.inline.hpp" 27 #include "gc/parallel/mutableSpace.hpp" 28 #include "gc/parallel/parallelScavengeHeap.hpp" 29 #include "gc/parallel/psOldGen.hpp" 30 #include "gc/parallel/psPromotionManager.inline.hpp" 31 #include "gc/parallel/psScavenge.inline.hpp" 32 #include "gc/shared/gcTrace.hpp" 33 #include "gc/shared/preservedMarks.inline.hpp" 34 #include "gc/shared/taskqueue.inline.hpp" 35 #include "logging/log.hpp" 36 #include "logging/logStream.hpp" 37 #include "memory/allocation.inline.hpp" 38 #include "memory/iterator.inline.hpp" 39 #include "memory/memRegion.hpp" 40 #include "memory/padded.inline.hpp" 41 #include "memory/resourceArea.hpp" 42 #include "oops/access.inline.hpp" 43 #include "oops/compressedOops.inline.hpp" 44 45 PaddedEnd<PSPromotionManager>* PSPromotionManager::_manager_array = NULL; 46 PSPromotionManager::OopStarTaskQueueSet* PSPromotionManager::_stack_array_depth = NULL; 47 PreservedMarksSet* PSPromotionManager::_preserved_marks_set = NULL; 48 PSOldGen* PSPromotionManager::_old_gen = NULL; 49 MutableSpace* PSPromotionManager::_young_space = NULL; 50 51 void PSPromotionManager::initialize() { 52 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 53 54 _old_gen = heap->old_gen(); 55 _young_space = heap->young_gen()->to_space(); 56 57 const uint promotion_manager_num = ParallelGCThreads + 1; 58 59 // To prevent false sharing, we pad the PSPromotionManagers 60 // and make sure that the first instance starts at a cache line. 61 assert(_manager_array == NULL, "Attempt to initialize twice"); 62 _manager_array = PaddedArray<PSPromotionManager, mtGC>::create_unfreeable(promotion_manager_num); 63 guarantee(_manager_array != NULL, "Could not initialize promotion manager"); 64 65 _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads); 66 guarantee(_stack_array_depth != NULL, "Could not initialize promotion manager"); 67 68 // Create and register the PSPromotionManager(s) for the worker threads. 69 for(uint i=0; i<ParallelGCThreads; i++) { 70 stack_array_depth()->register_queue(i, _manager_array[i].claimed_stack_depth()); 71 } 72 // The VMThread gets its own PSPromotionManager, which is not available 73 // for work stealing. 74 75 assert(_preserved_marks_set == NULL, "Attempt to initialize twice"); 76 _preserved_marks_set = new PreservedMarksSet(true /* in_c_heap */); 77 guarantee(_preserved_marks_set != NULL, "Could not initialize preserved marks set"); 78 _preserved_marks_set->init(promotion_manager_num); 79 for (uint i = 0; i < promotion_manager_num; i += 1) { 80 _manager_array[i].register_preserved_marks(_preserved_marks_set->get(i)); 81 } 82 } 83 84 // Helper functions to get around the circular dependency between 85 // psScavenge.inline.hpp and psPromotionManager.inline.hpp. 86 bool PSPromotionManager::should_scavenge(oop* p, bool check_to_space) { 87 return PSScavenge::should_scavenge(p, check_to_space); 88 } 89 bool PSPromotionManager::should_scavenge(narrowOop* p, bool check_to_space) { 90 return PSScavenge::should_scavenge(p, check_to_space); 91 } 92 93 PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(uint index) { 94 assert(index < ParallelGCThreads, "index out of range"); 95 assert(_manager_array != NULL, "Sanity"); 96 return &_manager_array[index]; 97 } 98 99 PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() { 100 assert(_manager_array != NULL, "Sanity"); 101 return &_manager_array[ParallelGCThreads]; 102 } 103 104 void PSPromotionManager::pre_scavenge() { 105 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 106 107 _preserved_marks_set->assert_empty(); 108 _young_space = heap->young_gen()->to_space(); 109 110 for(uint i=0; i<ParallelGCThreads+1; i++) { 111 manager_array(i)->reset(); 112 } 113 } 114 115 bool PSPromotionManager::post_scavenge(YoungGCTracer& gc_tracer) { 116 bool promotion_failure_occurred = false; 117 118 TASKQUEUE_STATS_ONLY(print_taskqueue_stats()); 119 for (uint i = 0; i < ParallelGCThreads + 1; i++) { 120 PSPromotionManager* manager = manager_array(i); 121 assert(manager->claimed_stack_depth()->is_empty(), "should be empty"); 122 if (manager->_promotion_failed_info.has_failed()) { 123 gc_tracer.report_promotion_failed(manager->_promotion_failed_info); 124 promotion_failure_occurred = true; 125 } 126 manager->flush_labs(); 127 } 128 if (!promotion_failure_occurred) { 129 // If there was no promotion failure, the preserved mark stacks 130 // should be empty. 131 _preserved_marks_set->assert_empty(); 132 } 133 return promotion_failure_occurred; 134 } 135 136 #if TASKQUEUE_STATS 137 void 138 PSPromotionManager::print_local_stats(outputStream* const out, uint i) const { 139 #define FMT " " SIZE_FORMAT_W(10) 140 out->print_cr("%3u" FMT FMT FMT FMT, i, _masked_pushes, _masked_steals, 141 _arrays_chunked, _array_chunks_processed); 142 #undef FMT 143 } 144 145 static const char* const pm_stats_hdr[] = { 146 " --------masked------- arrays array", 147 "thr push steal chunked chunks", 148 "--- ---------- ---------- ---------- ----------" 149 }; 150 151 void 152 PSPromotionManager::print_taskqueue_stats() { 153 if (!log_is_enabled(Trace, gc, task, stats)) { 154 return; 155 } 156 Log(gc, task, stats) log; 157 ResourceMark rm; 158 LogStream ls(log.trace()); 159 outputStream* out = &ls; 160 out->print_cr("== GC Tasks Stats, GC %3d", 161 ParallelScavengeHeap::heap()->total_collections()); 162 163 TaskQueueStats totals; 164 out->print("thr "); TaskQueueStats::print_header(1, out); out->cr(); 165 out->print("--- "); TaskQueueStats::print_header(2, out); out->cr(); 166 for (uint i = 0; i < ParallelGCThreads + 1; ++i) { 167 TaskQueueStats& next = manager_array(i)->_claimed_stack_depth.stats; 168 out->print("%3d ", i); next.print(out); out->cr(); 169 totals += next; 170 } 171 out->print("tot "); totals.print(out); out->cr(); 172 173 const uint hlines = sizeof(pm_stats_hdr) / sizeof(pm_stats_hdr[0]); 174 for (uint i = 0; i < hlines; ++i) out->print_cr("%s", pm_stats_hdr[i]); 175 for (uint i = 0; i < ParallelGCThreads + 1; ++i) { 176 manager_array(i)->print_local_stats(out, i); 177 } 178 } 179 180 void 181 PSPromotionManager::reset_stats() { 182 claimed_stack_depth()->stats.reset(); 183 _masked_pushes = _masked_steals = 0; 184 _arrays_chunked = _array_chunks_processed = 0; 185 } 186 #endif // TASKQUEUE_STATS 187 188 PSPromotionManager::PSPromotionManager() { 189 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 190 191 // We set the old lab's start array. 192 _old_lab.set_start_array(old_gen()->start_array()); 193 194 uint queue_size; 195 claimed_stack_depth()->initialize(); 196 queue_size = claimed_stack_depth()->max_elems(); 197 198 _totally_drain = (ParallelGCThreads == 1) || (GCDrainStackTargetSize == 0); 199 if (_totally_drain) { 200 _target_stack_size = 0; 201 } else { 202 // don't let the target stack size to be more than 1/4 of the entries 203 _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize, 204 (uint) (queue_size / 4)); 205 } 206 207 _array_chunk_size = ParGCArrayScanChunk; 208 // let's choose 1.5x the chunk size 209 _min_array_size_for_chunking = 3 * _array_chunk_size / 2; 210 211 _preserved_marks = NULL; 212 213 reset(); 214 } 215 216 void PSPromotionManager::reset() { 217 assert(stacks_empty(), "reset of non-empty stack"); 218 219 // We need to get an assert in here to make sure the labs are always flushed. 220 221 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 222 223 // Do not prefill the LAB's, save heap wastage! 224 HeapWord* lab_base = young_space()->top(); 225 _young_lab.initialize(MemRegion(lab_base, (size_t)0)); 226 _young_gen_is_full = false; 227 228 lab_base = old_gen()->object_space()->top(); 229 _old_lab.initialize(MemRegion(lab_base, (size_t)0)); 230 _old_gen_is_full = false; 231 232 _promotion_failed_info.reset(); 233 234 TASKQUEUE_STATS_ONLY(reset_stats()); 235 } 236 237 void PSPromotionManager::register_preserved_marks(PreservedMarks* preserved_marks) { 238 assert(_preserved_marks == NULL, "do not set it twice"); 239 _preserved_marks = preserved_marks; 240 } 241 242 void PSPromotionManager::restore_preserved_marks() { 243 _preserved_marks_set->restore(&ParallelScavengeHeap::heap()->workers()); 244 } 245 246 void PSPromotionManager::drain_stacks_depth(bool totally_drain) { 247 totally_drain = totally_drain || _totally_drain; 248 249 #ifdef ASSERT 250 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 251 MutableSpace* to_space = heap->young_gen()->to_space(); 252 MutableSpace* old_space = heap->old_gen()->object_space(); 253 #endif /* ASSERT */ 254 255 OopStarTaskQueue* const tq = claimed_stack_depth(); 256 do { 257 StarTask p; 258 259 // Drain overflow stack first, so other threads can steal from 260 // claimed stack while we work. 261 while (tq->pop_overflow(p)) { 262 process_popped_location_depth(p); 263 } 264 265 if (totally_drain) { 266 while (tq->pop_local(p)) { 267 process_popped_location_depth(p); 268 } 269 } else { 270 while (tq->size() > _target_stack_size && tq->pop_local(p)) { 271 process_popped_location_depth(p); 272 } 273 } 274 } while ((totally_drain && !tq->taskqueue_empty()) || !tq->overflow_empty()); 275 276 assert(!totally_drain || tq->taskqueue_empty(), "Sanity"); 277 assert(totally_drain || tq->size() <= _target_stack_size, "Sanity"); 278 assert(tq->overflow_empty(), "Sanity"); 279 } 280 281 void PSPromotionManager::flush_labs() { 282 assert(stacks_empty(), "Attempt to flush lab with live stack"); 283 284 // If either promotion lab fills up, we can flush the 285 // lab but not refill it, so check first. 286 assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity"); 287 if (!_young_lab.is_flushed()) 288 _young_lab.flush(); 289 290 assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity"); 291 if (!_old_lab.is_flushed()) 292 _old_lab.flush(); 293 294 // Let PSScavenge know if we overflowed 295 if (_young_gen_is_full) { 296 PSScavenge::set_survivor_overflow(true); 297 } 298 } 299 300 template <class T> void PSPromotionManager::process_array_chunk_work( 301 oop obj, 302 int start, int end) { 303 assert(start <= end, "invariant"); 304 T* const base = (T*)objArrayOop(obj)->base(); 305 T* p = base + start; 306 T* const chunk_end = base + end; 307 while (p < chunk_end) { 308 if (PSScavenge::should_scavenge(p)) { 309 claim_or_forward_depth(p); 310 } 311 ++p; 312 } 313 } 314 315 void PSPromotionManager::process_array_chunk(oop old) { 316 assert(PSChunkLargeArrays, "invariant"); 317 assert(old->is_objArray(), "invariant"); 318 assert(old->is_forwarded(), "invariant"); 319 320 TASKQUEUE_STATS_ONLY(++_array_chunks_processed); 321 322 oop const obj = old->forwardee(); 323 324 int start; 325 int const end = arrayOop(old)->length(); 326 if (end > (int) _min_array_size_for_chunking) { 327 // we'll chunk more 328 start = end - _array_chunk_size; 329 assert(start > 0, "invariant"); 330 arrayOop(old)->set_length(start); 331 push_depth(mask_chunked_array_oop(old)); 332 TASKQUEUE_STATS_ONLY(++_masked_pushes); 333 } else { 334 // this is the final chunk for this array 335 start = 0; 336 int const actual_length = arrayOop(obj)->length(); 337 arrayOop(old)->set_length(actual_length); 338 } 339 340 if (UseCompressedOops) { 341 process_array_chunk_work<narrowOop>(obj, start, end); 342 } else { 343 process_array_chunk_work<oop>(obj, start, end); 344 } 345 } 346 347 oop PSPromotionManager::oop_promotion_failed(oop obj, markWord obj_mark) { 348 assert(_old_gen_is_full || PromotionFailureALot, "Sanity"); 349 350 // Attempt to CAS in the header. 351 // This tests if the header is still the same as when 352 // this started. If it is the same (i.e., no forwarding 353 // pointer has been installed), then this thread owns 354 // it. 355 if (obj->cas_forward_to(obj, obj_mark)) { 356 // We won any races, we "own" this object. 357 assert(obj == obj->forwardee(), "Sanity"); 358 359 _promotion_failed_info.register_copy_failure(obj->size()); 360 361 push_contents(obj); 362 363 _preserved_marks->push_if_necessary(obj, obj_mark); 364 } else { 365 // We lost, someone else "owns" this object 366 guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed."); 367 368 // No unallocation to worry about. 369 obj = obj->forwardee(); 370 } 371 372 log_develop_trace(gc, scavenge)("{promotion-failure %s " PTR_FORMAT " (%d)}", obj->klass()->internal_name(), p2i(obj), obj->size()); 373 374 return obj; 375 }