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::PSScannerTasksQueueSet* 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 64 _stack_array_depth = new PSScannerTasksQueueSet(ParallelGCThreads); 65 66 // Create and register the PSPromotionManager(s) for the worker threads. 67 for(uint i=0; i<ParallelGCThreads; i++) { 68 stack_array_depth()->register_queue(i, _manager_array[i].claimed_stack_depth()); 69 } 70 // The VMThread gets its own PSPromotionManager, which is not available 71 // for work stealing. 72 73 assert(_preserved_marks_set == NULL, "Attempt to initialize twice"); 74 _preserved_marks_set = new PreservedMarksSet(true /* in_c_heap */); 75 _preserved_marks_set->init(promotion_manager_num); 76 for (uint i = 0; i < promotion_manager_num; i += 1) { 77 _manager_array[i].register_preserved_marks(_preserved_marks_set->get(i)); 78 } 79 } 80 81 // Helper functions to get around the circular dependency between 82 // psScavenge.inline.hpp and psPromotionManager.inline.hpp. 83 bool PSPromotionManager::should_scavenge(oop* p, bool check_to_space) { 84 return PSScavenge::should_scavenge(p, check_to_space); 85 } 86 bool PSPromotionManager::should_scavenge(narrowOop* p, bool check_to_space) { 87 return PSScavenge::should_scavenge(p, check_to_space); 88 } 89 90 PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(uint index) { 91 assert(index < ParallelGCThreads, "index out of range"); 92 assert(_manager_array != NULL, "Sanity"); 93 return &_manager_array[index]; 94 } 95 96 PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() { 97 assert(_manager_array != NULL, "Sanity"); 98 return &_manager_array[ParallelGCThreads]; 99 } 100 101 void PSPromotionManager::pre_scavenge() { 102 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 103 104 _preserved_marks_set->assert_empty(); 105 _young_space = heap->young_gen()->to_space(); 106 107 for(uint i=0; i<ParallelGCThreads+1; i++) { 108 manager_array(i)->reset(); 109 } 110 } 111 112 bool PSPromotionManager::post_scavenge(YoungGCTracer& gc_tracer) { 113 bool promotion_failure_occurred = false; 114 115 TASKQUEUE_STATS_ONLY(print_taskqueue_stats()); 116 for (uint i = 0; i < ParallelGCThreads + 1; i++) { 117 PSPromotionManager* manager = manager_array(i); 118 assert(manager->claimed_stack_depth()->is_empty(), "should be empty"); 119 if (manager->_promotion_failed_info.has_failed()) { 120 gc_tracer.report_promotion_failed(manager->_promotion_failed_info); 121 promotion_failure_occurred = true; 122 } 123 manager->flush_labs(); 124 } 125 if (!promotion_failure_occurred) { 126 // If there was no promotion failure, the preserved mark stacks 127 // should be empty. 128 _preserved_marks_set->assert_empty(); 129 } 130 return promotion_failure_occurred; 131 } 132 133 #if TASKQUEUE_STATS 134 void 135 PSPromotionManager::print_local_stats(outputStream* const out, uint i) const { 136 #define FMT " " SIZE_FORMAT_W(10) 137 out->print_cr("%3u" FMT FMT FMT FMT, 138 i, _array_chunk_pushes, _array_chunk_steals, 139 _arrays_chunked, _array_chunks_processed); 140 #undef FMT 141 } 142 143 static const char* const pm_stats_hdr[] = { 144 " ----partial array---- arrays array", 145 "thr push steal chunked chunks", 146 "--- ---------- ---------- ---------- ----------" 147 }; 148 149 void 150 PSPromotionManager::print_taskqueue_stats() { 151 if (!log_is_enabled(Trace, gc, task, stats)) { 152 return; 153 } 154 Log(gc, task, stats) log; 155 ResourceMark rm; 156 LogStream ls(log.trace()); 157 outputStream* out = &ls; 158 out->print_cr("== GC Tasks Stats, GC %3d", 159 ParallelScavengeHeap::heap()->total_collections()); 160 161 TaskQueueStats totals; 162 out->print("thr "); TaskQueueStats::print_header(1, out); out->cr(); 163 out->print("--- "); TaskQueueStats::print_header(2, out); out->cr(); 164 for (uint i = 0; i < ParallelGCThreads + 1; ++i) { 165 TaskQueueStats& next = manager_array(i)->_claimed_stack_depth.stats; 166 out->print("%3d ", i); next.print(out); out->cr(); 167 totals += next; 168 } 169 out->print("tot "); totals.print(out); out->cr(); 170 171 const uint hlines = sizeof(pm_stats_hdr) / sizeof(pm_stats_hdr[0]); 172 for (uint i = 0; i < hlines; ++i) out->print_cr("%s", pm_stats_hdr[i]); 173 for (uint i = 0; i < ParallelGCThreads + 1; ++i) { 174 manager_array(i)->print_local_stats(out, i); 175 } 176 } 177 178 void 179 PSPromotionManager::reset_stats() { 180 claimed_stack_depth()->stats.reset(); 181 _array_chunk_pushes = _array_chunk_steals = 0; 182 _arrays_chunked = _array_chunks_processed = 0; 183 } 184 #endif // TASKQUEUE_STATS 185 186 PSPromotionManager::PSPromotionManager() { 187 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 188 189 // We set the old lab's start array. 190 _old_lab.set_start_array(old_gen()->start_array()); 191 192 uint queue_size; 193 claimed_stack_depth()->initialize(); 194 queue_size = claimed_stack_depth()->max_elems(); 195 196 _totally_drain = (ParallelGCThreads == 1) || (GCDrainStackTargetSize == 0); 197 if (_totally_drain) { 198 _target_stack_size = 0; 199 } else { 200 // don't let the target stack size to be more than 1/4 of the entries 201 _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize, 202 (uint) (queue_size / 4)); 203 } 204 205 _array_chunk_size = ParGCArrayScanChunk; 206 // let's choose 1.5x the chunk size 207 _min_array_size_for_chunking = 3 * _array_chunk_size / 2; 208 209 _preserved_marks = NULL; 210 211 reset(); 212 } 213 214 void PSPromotionManager::reset() { 215 assert(stacks_empty(), "reset of non-empty stack"); 216 217 // We need to get an assert in here to make sure the labs are always flushed. 218 219 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 220 221 // Do not prefill the LAB's, save heap wastage! 222 HeapWord* lab_base = young_space()->top(); 223 _young_lab.initialize(MemRegion(lab_base, (size_t)0)); 224 _young_gen_is_full = false; 225 226 lab_base = old_gen()->object_space()->top(); 227 _old_lab.initialize(MemRegion(lab_base, (size_t)0)); 228 _old_gen_is_full = false; 229 230 _promotion_failed_info.reset(); 231 232 TASKQUEUE_STATS_ONLY(reset_stats()); 233 } 234 235 void PSPromotionManager::register_preserved_marks(PreservedMarks* preserved_marks) { 236 assert(_preserved_marks == NULL, "do not set it twice"); 237 _preserved_marks = preserved_marks; 238 } 239 240 void PSPromotionManager::restore_preserved_marks() { 241 _preserved_marks_set->restore(&ParallelScavengeHeap::heap()->workers()); 242 } 243 244 void PSPromotionManager::drain_stacks_depth(bool totally_drain) { 245 totally_drain = totally_drain || _totally_drain; 246 247 #ifdef ASSERT 248 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 249 MutableSpace* to_space = heap->young_gen()->to_space(); 250 MutableSpace* old_space = heap->old_gen()->object_space(); 251 #endif /* ASSERT */ 252 253 PSScannerTasksQueue* const tq = claimed_stack_depth(); 254 do { 255 ScannerTask task; 256 257 // Drain overflow stack first, so other threads can steal from 258 // claimed stack while we work. 259 while (tq->pop_overflow(task)) { 260 process_popped_location_depth(task); 261 } 262 263 if (totally_drain) { 264 while (tq->pop_local(task)) { 265 process_popped_location_depth(task); 266 } 267 } else { 268 while (tq->size() > _target_stack_size && tq->pop_local(task)) { 269 process_popped_location_depth(task); 270 } 271 } 272 } while ((totally_drain && !tq->taskqueue_empty()) || !tq->overflow_empty()); 273 274 assert(!totally_drain || tq->taskqueue_empty(), "Sanity"); 275 assert(totally_drain || tq->size() <= _target_stack_size, "Sanity"); 276 assert(tq->overflow_empty(), "Sanity"); 277 } 278 279 void PSPromotionManager::flush_labs() { 280 assert(stacks_empty(), "Attempt to flush lab with live stack"); 281 282 // If either promotion lab fills up, we can flush the 283 // lab but not refill it, so check first. 284 assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity"); 285 if (!_young_lab.is_flushed()) 286 _young_lab.flush(); 287 288 assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity"); 289 if (!_old_lab.is_flushed()) 290 _old_lab.flush(); 291 292 // Let PSScavenge know if we overflowed 293 if (_young_gen_is_full) { 294 PSScavenge::set_survivor_overflow(true); 295 } 296 } 297 298 template <class T> void PSPromotionManager::process_array_chunk_work( 299 oop obj, 300 int start, int end) { 301 assert(start <= end, "invariant"); 302 T* const base = (T*)objArrayOop(obj)->base(); 303 T* p = base + start; 304 T* const chunk_end = base + end; 305 while (p < chunk_end) { 306 if (PSScavenge::should_scavenge(p)) { 307 claim_or_forward_depth(p); 308 } 309 ++p; 310 } 311 } 312 313 void PSPromotionManager::process_array_chunk(PartialArrayScanTask task) { 314 assert(PSChunkLargeArrays, "invariant"); 315 316 oop old = task.to_source_array(); 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(ScannerTask(PartialArrayScanTask(old))); 332 TASKQUEUE_STATS_ONLY(++_array_chunk_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 // Save the markWord of promotion-failed objs in _preserved_marks for later 364 // restoration. This way we don't have to walk the young-gen to locate 365 // these promotion-failed objs. 366 _preserved_marks->push_always(obj, obj_mark); 367 } else { 368 // We lost, someone else "owns" this object 369 guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed."); 370 371 // No unallocation to worry about. 372 obj = obj->forwardee(); 373 } 374 375 log_develop_trace(gc, scavenge)("{promotion-failure %s " PTR_FORMAT " (%d)}", obj->klass()->internal_name(), p2i(obj), obj->size()); 376 377 return obj; 378 } --- EOF ---