1 /* 2 * Copyright (c) 2002, 2023, 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 #ifndef SHARE_GC_PARALLEL_PSPROMOTIONMANAGER_INLINE_HPP 26 #define SHARE_GC_PARALLEL_PSPROMOTIONMANAGER_INLINE_HPP 27 28 #include "gc/parallel/psPromotionManager.hpp" 29 30 #include "gc/parallel/parallelScavengeHeap.hpp" 31 #include "gc/parallel/parMarkBitMap.inline.hpp" 32 #include "gc/parallel/psOldGen.hpp" 33 #include "gc/parallel/psPromotionLAB.inline.hpp" 34 #include "gc/parallel/psScavenge.inline.hpp" 35 #include "gc/parallel/psStringDedup.hpp" 36 #include "gc/shared/continuationGCSupport.inline.hpp" 37 #include "gc/shared/taskqueue.inline.hpp" 38 #include "gc/shared/tlab_globals.hpp" 39 #include "logging/log.hpp" 40 #include "memory/iterator.inline.hpp" 41 #include "oops/access.inline.hpp" 42 #include "oops/oop.inline.hpp" 43 #include "runtime/orderAccess.hpp" 44 #include "runtime/prefetch.inline.hpp" 45 #include "utilities/copy.hpp" 46 47 inline PSPromotionManager* PSPromotionManager::manager_array(uint index) { 48 assert(_manager_array != nullptr, "access of null manager_array"); 49 assert(index < ParallelGCThreads, "out of range manager_array access"); 50 return &_manager_array[index]; 51 } 52 53 inline void PSPromotionManager::push_depth(ScannerTask task) { 54 claimed_stack_depth()->push(task); 55 } 56 57 template <class T> 58 inline void PSPromotionManager::claim_or_forward_depth(T* p) { 59 assert(should_scavenge(p, true), "revisiting object?"); 60 assert(ParallelScavengeHeap::heap()->is_in(p), "pointer outside heap"); 61 oop obj = RawAccess<IS_NOT_NULL>::oop_load(p); 62 Prefetch::write(obj->mark_addr(), 0); 63 push_depth(ScannerTask(p)); 64 } 65 66 inline void PSPromotionManager::promotion_trace_event(oop new_obj, oop old_obj, 67 size_t obj_size, 68 uint age, bool tenured, 69 const PSPromotionLAB* lab) { 70 // Skip if memory allocation failed 71 if (new_obj != nullptr) { 72 const ParallelScavengeTracer* gc_tracer = PSScavenge::gc_tracer(); 73 74 if (lab != nullptr) { 75 // Promotion of object through newly allocated PLAB 76 if (gc_tracer->should_report_promotion_in_new_plab_event()) { 77 size_t obj_bytes = obj_size * HeapWordSize; 78 size_t lab_size = lab->capacity(); 79 gc_tracer->report_promotion_in_new_plab_event(old_obj->klass(), obj_bytes, 80 age, tenured, lab_size); 81 } 82 } else { 83 // Promotion of object directly to heap 84 if (gc_tracer->should_report_promotion_outside_plab_event()) { 85 size_t obj_bytes = obj_size * HeapWordSize; 86 gc_tracer->report_promotion_outside_plab_event(old_obj->klass(), obj_bytes, 87 age, tenured); 88 } 89 } 90 } 91 } 92 93 class PSPushContentsClosure: public BasicOopIterateClosure { 94 PSPromotionManager* _pm; 95 public: 96 PSPushContentsClosure(PSPromotionManager* pm) : BasicOopIterateClosure(PSScavenge::reference_processor()), _pm(pm) {} 97 98 template <typename T> void do_oop_nv(T* p) { 99 if (PSScavenge::should_scavenge(p)) { 100 _pm->claim_or_forward_depth(p); 101 } 102 } 103 104 virtual void do_oop(oop* p) { do_oop_nv(p); } 105 virtual void do_oop(narrowOop* p) { do_oop_nv(p); } 106 }; 107 108 // 109 // This closure specialization will override the one that is defined in 110 // instanceRefKlass.inline.cpp. It swaps the order of oop_oop_iterate and 111 // oop_oop_iterate_ref_processing. Unfortunately G1 and Parallel behaves 112 // significantly better (especially in the Derby benchmark) using opposite 113 // order of these function calls. 114 // 115 template <> 116 inline void InstanceRefKlass::oop_oop_iterate_reverse<oop, PSPushContentsClosure>(oop obj, PSPushContentsClosure* closure) { 117 oop_oop_iterate_ref_processing<oop>(obj, closure); 118 InstanceKlass::oop_oop_iterate_reverse<oop>(obj, closure); 119 } 120 121 template <> 122 inline void InstanceRefKlass::oop_oop_iterate_reverse<narrowOop, PSPushContentsClosure>(oop obj, PSPushContentsClosure* closure) { 123 oop_oop_iterate_ref_processing<narrowOop>(obj, closure); 124 InstanceKlass::oop_oop_iterate_reverse<narrowOop>(obj, closure); 125 } 126 127 inline void PSPromotionManager::push_contents(oop obj) { 128 if (!obj->klass()->is_typeArray_klass()) { 129 PSPushContentsClosure pcc(this); 130 obj->oop_iterate_backwards(&pcc); 131 } 132 } 133 134 template<bool promote_immediately> 135 inline oop PSPromotionManager::copy_to_survivor_space(oop o) { 136 assert(should_scavenge(&o), "Sanity"); 137 138 // NOTE! We must be very careful with any methods that access the mark 139 // in o. There may be multiple threads racing on it, and it may be forwarded 140 // at any time. 141 markWord m = o->mark(); 142 if (!m.is_marked()) { 143 return copy_unmarked_to_survivor_space<promote_immediately>(o, m); 144 } else { 145 // Ensure any loads from the forwardee follow all changes that precede 146 // the release-cmpxchg that performed the forwarding, possibly in some 147 // other thread. 148 OrderAccess::acquire(); 149 // Return the already installed forwardee. 150 return cast_to_oop(m.decode_pointer()); 151 } 152 } 153 154 // 155 // This method is pretty bulky. It would be nice to split it up 156 // into smaller submethods, but we need to be careful not to hurt 157 // performance. 158 // 159 template<bool promote_immediately> 160 inline oop PSPromotionManager::copy_unmarked_to_survivor_space(oop o, 161 markWord test_mark) { 162 assert(should_scavenge(&o), "Sanity"); 163 164 oop new_obj = nullptr; 165 bool new_obj_is_tenured = false; 166 size_t new_obj_size = o->size(); 167 168 // Find the objects age, MT safe. 169 uint age = (test_mark.has_displaced_mark_helper() /* o->has_displaced_mark() */) ? 170 test_mark.displaced_mark_helper().age() : test_mark.age(); 171 172 if (!promote_immediately) { 173 // Try allocating obj in to-space (unless too old) 174 if (age < PSScavenge::tenuring_threshold()) { 175 new_obj = cast_to_oop(_young_lab.allocate(new_obj_size)); 176 if (new_obj == nullptr && !_young_gen_is_full) { 177 // Do we allocate directly, or flush and refill? 178 if (new_obj_size > (YoungPLABSize / 2)) { 179 // Allocate this object directly 180 new_obj = cast_to_oop(young_space()->cas_allocate(new_obj_size)); 181 promotion_trace_event(new_obj, o, new_obj_size, age, false, nullptr); 182 } else { 183 // Flush and fill 184 _young_lab.flush(); 185 186 HeapWord* lab_base = young_space()->cas_allocate(YoungPLABSize); 187 if (lab_base != nullptr) { 188 _young_lab.initialize(MemRegion(lab_base, YoungPLABSize)); 189 // Try the young lab allocation again. 190 new_obj = cast_to_oop(_young_lab.allocate(new_obj_size)); 191 promotion_trace_event(new_obj, o, new_obj_size, age, false, &_young_lab); 192 } else { 193 _young_gen_is_full = true; 194 } 195 } 196 } 197 } 198 } 199 200 // Otherwise try allocating obj tenured 201 if (new_obj == nullptr) { 202 #ifndef PRODUCT 203 if (ParallelScavengeHeap::heap()->promotion_should_fail()) { 204 return oop_promotion_failed(o, test_mark); 205 } 206 #endif // #ifndef PRODUCT 207 208 new_obj = cast_to_oop(_old_lab.allocate(new_obj_size)); 209 new_obj_is_tenured = true; 210 211 if (new_obj == nullptr) { 212 if (!_old_gen_is_full) { 213 // Do we allocate directly, or flush and refill? 214 if (new_obj_size > (OldPLABSize / 2)) { 215 // Allocate this object directly 216 new_obj = cast_to_oop(old_gen()->allocate(new_obj_size)); 217 promotion_trace_event(new_obj, o, new_obj_size, age, true, nullptr); 218 } else { 219 // Flush and fill 220 _old_lab.flush(); 221 222 HeapWord* lab_base = old_gen()->allocate(OldPLABSize); 223 if(lab_base != nullptr) { 224 _old_lab.initialize(MemRegion(lab_base, OldPLABSize)); 225 // Try the old lab allocation again. 226 new_obj = cast_to_oop(_old_lab.allocate(new_obj_size)); 227 promotion_trace_event(new_obj, o, new_obj_size, age, true, &_old_lab); 228 } 229 } 230 } 231 232 // This is the promotion failed test, and code handling. 233 // The code belongs here for two reasons. It is slightly 234 // different than the code below, and cannot share the 235 // CAS testing code. Keeping the code here also minimizes 236 // the impact on the common case fast path code. 237 238 if (new_obj == nullptr) { 239 _old_gen_is_full = true; 240 return oop_promotion_failed(o, test_mark); 241 } 242 } 243 } 244 245 assert(new_obj != nullptr, "allocation should have succeeded"); 246 247 // Copy obj 248 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(o), cast_from_oop<HeapWord*>(new_obj), new_obj_size); 249 250 // Parallel GC claims with a release - so other threads might access this object 251 // after claiming and they should see the "completed" object. 252 ContinuationGCSupport::transform_stack_chunk(new_obj); 253 254 // Now we have to CAS in the header. 255 // Make copy visible to threads reading the forwardee. 256 oop forwardee = o->forward_to_atomic(new_obj, test_mark, memory_order_release); 257 if (forwardee == nullptr) { // forwardee is null when forwarding is successful 258 // We won any races, we "own" this object. 259 assert(new_obj == o->forwardee(), "Sanity"); 260 261 // Increment age if obj still in new generation. Now that 262 // we're dealing with a markWord that cannot change, it is 263 // okay to use the non mt safe oop methods. 264 if (!new_obj_is_tenured) { 265 new_obj->incr_age(); 266 assert(young_space()->contains(new_obj), "Attempt to push non-promoted obj"); 267 } 268 269 // Do the size comparison first with new_obj_size, which we 270 // already have. Hopefully, only a few objects are larger than 271 // _min_array_size_for_chunking, and most of them will be arrays. 272 // So, the is->objArray() test would be very infrequent. 273 if (new_obj_size > _min_array_size_for_chunking && 274 new_obj->is_objArray() && 275 PSChunkLargeArrays) { 276 // we'll chunk it 277 push_depth(ScannerTask(PartialArrayScanTask(o))); 278 TASKQUEUE_STATS_ONLY(++_arrays_chunked; ++_array_chunk_pushes); 279 } else { 280 // we'll just push its contents 281 push_contents(new_obj); 282 283 if (StringDedup::is_enabled() && 284 java_lang_String::is_instance(new_obj) && 285 psStringDedup::is_candidate_from_evacuation(new_obj, new_obj_is_tenured)) { 286 _string_dedup_requests.add(o); 287 } 288 } 289 return new_obj; 290 } else { 291 // We lost, someone else "owns" this object. 292 // Ensure loads from the forwardee follow all changes that preceded the 293 // release-cmpxchg that performed the forwarding in another thread. 294 OrderAccess::acquire(); 295 296 assert(o->is_forwarded(), "Object must be forwarded if the cas failed."); 297 assert(o->forwardee() == forwardee, "invariant"); 298 299 if (new_obj_is_tenured) { 300 _old_lab.unallocate_object(cast_from_oop<HeapWord*>(new_obj), new_obj_size); 301 } else { 302 _young_lab.unallocate_object(cast_from_oop<HeapWord*>(new_obj), new_obj_size); 303 } 304 return forwardee; 305 } 306 } 307 308 // Attempt to "claim" oop at p via CAS, push the new obj if successful 309 template <bool promote_immediately, class T> 310 inline void PSPromotionManager::copy_and_push_safe_barrier(T* p) { 311 assert(ParallelScavengeHeap::heap()->is_in_reserved(p), "precondition"); 312 assert(should_scavenge(p, true), "revisiting object?"); 313 314 oop o = RawAccess<IS_NOT_NULL>::oop_load(p); 315 oop new_obj = copy_to_survivor_space<promote_immediately>(o); 316 RawAccess<IS_NOT_NULL>::oop_store(p, new_obj); 317 318 if (!PSScavenge::is_obj_in_young((HeapWord*)p) && 319 PSScavenge::is_obj_in_young(new_obj)) { 320 PSScavenge::card_table()->inline_write_ref_field_gc(p); 321 } 322 } 323 324 inline void PSPromotionManager::process_popped_location_depth(ScannerTask task) { 325 if (task.is_partial_array_task()) { 326 assert(PSChunkLargeArrays, "invariant"); 327 process_array_chunk(task.to_partial_array_task()); 328 } else { 329 if (task.is_narrow_oop_ptr()) { 330 assert(UseCompressedOops, "Error"); 331 copy_and_push_safe_barrier</*promote_immediately=*/false>(task.to_narrow_oop_ptr()); 332 } else { 333 copy_and_push_safe_barrier</*promote_immediately=*/false>(task.to_oop_ptr()); 334 } 335 } 336 } 337 338 inline bool PSPromotionManager::steal_depth(int queue_num, ScannerTask& t) { 339 return stack_array_depth()->steal(queue_num, t); 340 } 341 342 #if TASKQUEUE_STATS 343 void PSPromotionManager::record_steal(ScannerTask task) { 344 if (task.is_partial_array_task()) { 345 ++_array_chunk_steals; 346 } 347 } 348 #endif // TASKQUEUE_STATS 349 350 #endif // SHARE_GC_PARALLEL_PSPROMOTIONMANAGER_INLINE_HPP