1 /* 2 * Copyright (c) 2002, 2015, 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/parallel/mutableSpace.hpp" 27 #include "gc/parallel/parallelScavengeHeap.hpp" 28 #include "gc/parallel/psOldGen.hpp" 29 #include "gc/parallel/psPromotionManager.inline.hpp" 30 #include "gc/parallel/psScavenge.inline.hpp" 31 #include "gc/shared/gcTrace.hpp" 32 #include "gc/shared/taskqueue.inline.hpp" 33 #include "memory/allocation.inline.hpp" 34 #include "memory/memRegion.hpp" 35 #include "memory/padded.inline.hpp" 36 #include "oops/instanceKlass.inline.hpp" 37 #include "oops/instanceMirrorKlass.inline.hpp" 38 #include "oops/objArrayKlass.inline.hpp" 39 #include "oops/oop.inline.hpp" 40 41 PaddedEnd<PSPromotionManager>* PSPromotionManager::_manager_array = NULL; 42 OopStarTaskQueueSet* PSPromotionManager::_stack_array_depth = NULL; 43 PSOldGen* PSPromotionManager::_old_gen = NULL; 44 MutableSpace* PSPromotionManager::_young_space = NULL; 45 46 void PSPromotionManager::initialize() { 47 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 48 49 _old_gen = heap->old_gen(); 50 _young_space = heap->young_gen()->to_space(); 51 52 // To prevent false sharing, we pad the PSPromotionManagers 53 // and make sure that the first instance starts at a cache line. 54 assert(_manager_array == NULL, "Attempt to initialize twice"); 55 _manager_array = PaddedArray<PSPromotionManager, mtGC>::create_unfreeable(ParallelGCThreads + 1); 56 guarantee(_manager_array != NULL, "Could not initialize promotion manager"); 57 58 _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads); 59 guarantee(_stack_array_depth != NULL, "Could not initialize promotion manager"); 60 61 // Create and register the PSPromotionManager(s) for the worker threads. 62 for(uint i=0; i<ParallelGCThreads; i++) { 63 stack_array_depth()->register_queue(i, _manager_array[i].claimed_stack_depth()); 64 } 65 // The VMThread gets its own PSPromotionManager, which is not available 66 // for work stealing. 67 } 68 69 // Helper functions to get around the circular dependency between 70 // psScavenge.inline.hpp and psPromotionManager.inline.hpp. 71 bool PSPromotionManager::should_scavenge(oop* p, bool check_to_space) { 72 return PSScavenge::should_scavenge(p, check_to_space); 73 } 74 bool PSPromotionManager::should_scavenge(narrowOop* p, bool check_to_space) { 75 return PSScavenge::should_scavenge(p, check_to_space); 76 } 77 78 PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(uint index) { 79 assert(index < ParallelGCThreads, "index out of range"); 80 assert(_manager_array != NULL, "Sanity"); 81 return &_manager_array[index]; 82 } 83 84 PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() { 85 assert(_manager_array != NULL, "Sanity"); 86 return &_manager_array[ParallelGCThreads]; 87 } 88 89 void PSPromotionManager::pre_scavenge() { 90 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 91 92 _young_space = heap->young_gen()->to_space(); 93 94 for(uint i=0; i<ParallelGCThreads+1; i++) { 95 manager_array(i)->reset(); 96 } 97 } 98 99 bool PSPromotionManager::post_scavenge(YoungGCTracer& gc_tracer) { 100 bool promotion_failure_occurred = false; 101 102 TASKQUEUE_STATS_ONLY(if (PrintTaskqueue) print_taskqueue_stats()); 103 for (uint i = 0; i < ParallelGCThreads + 1; i++) { 104 PSPromotionManager* manager = manager_array(i); 105 assert(manager->claimed_stack_depth()->is_empty(), "should be empty"); 106 if (manager->_promotion_failed_info.has_failed()) { 107 gc_tracer.report_promotion_failed(manager->_promotion_failed_info); 108 promotion_failure_occurred = true; 109 } 110 manager->flush_labs(); 111 } 112 return promotion_failure_occurred; 113 } 114 115 #if TASKQUEUE_STATS 116 void 117 PSPromotionManager::print_local_stats(outputStream* const out, uint i) const { 118 #define FMT " " SIZE_FORMAT_W(10) 119 out->print_cr("%3u" FMT FMT FMT FMT, i, _masked_pushes, _masked_steals, 120 _arrays_chunked, _array_chunks_processed); 121 #undef FMT 122 } 123 124 static const char* const pm_stats_hdr[] = { 125 " --------masked------- arrays array", 126 "thr push steal chunked chunks", 127 "--- ---------- ---------- ---------- ----------" 128 }; 129 130 void 131 PSPromotionManager::print_taskqueue_stats(outputStream* const out) { 132 out->print_cr("== GC Tasks Stats, GC %3d", 133 ParallelScavengeHeap::heap()->total_collections()); 134 135 TaskQueueStats totals; 136 out->print("thr "); TaskQueueStats::print_header(1, out); out->cr(); 137 out->print("--- "); TaskQueueStats::print_header(2, out); out->cr(); 138 for (uint i = 0; i < ParallelGCThreads + 1; ++i) { 139 TaskQueueStats& next = manager_array(i)->_claimed_stack_depth.stats; 140 out->print("%3d ", i); next.print(out); out->cr(); 141 totals += next; 142 } 143 out->print("tot "); totals.print(out); out->cr(); 144 145 const uint hlines = sizeof(pm_stats_hdr) / sizeof(pm_stats_hdr[0]); 146 for (uint i = 0; i < hlines; ++i) out->print_cr("%s", pm_stats_hdr[i]); 147 for (uint i = 0; i < ParallelGCThreads + 1; ++i) { 148 manager_array(i)->print_local_stats(out, i); 149 } 150 } 151 152 void 153 PSPromotionManager::reset_stats() { 154 claimed_stack_depth()->stats.reset(); 155 _masked_pushes = _masked_steals = 0; 156 _arrays_chunked = _array_chunks_processed = 0; 157 } 158 #endif // TASKQUEUE_STATS 159 160 PSPromotionManager::PSPromotionManager() { 161 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 162 163 // We set the old lab's start array. 164 _old_lab.set_start_array(old_gen()->start_array()); 165 166 uint queue_size; 167 claimed_stack_depth()->initialize(); 168 queue_size = claimed_stack_depth()->max_elems(); 169 170 _totally_drain = (ParallelGCThreads == 1) || (GCDrainStackTargetSize == 0); 171 if (_totally_drain) { 172 _target_stack_size = 0; 173 } else { 174 // don't let the target stack size to be more than 1/4 of the entries 175 _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize, 176 (uint) (queue_size / 4)); 177 } 178 179 _array_chunk_size = ParGCArrayScanChunk; 180 // let's choose 1.5x the chunk size 181 _min_array_size_for_chunking = 3 * _array_chunk_size / 2; 182 183 reset(); 184 } 185 186 void PSPromotionManager::reset() { 187 assert(stacks_empty(), "reset of non-empty stack"); 188 189 // We need to get an assert in here to make sure the labs are always flushed. 190 191 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 192 193 // Do not prefill the LAB's, save heap wastage! 194 HeapWord* lab_base = young_space()->top(); 195 _young_lab.initialize(MemRegion(lab_base, (size_t)0)); 196 _young_gen_is_full = false; 197 198 lab_base = old_gen()->object_space()->top(); 199 _old_lab.initialize(MemRegion(lab_base, (size_t)0)); 200 _old_gen_is_full = false; 201 202 _promotion_failed_info.reset(); 203 204 TASKQUEUE_STATS_ONLY(reset_stats()); 205 } 206 207 208 void PSPromotionManager::drain_stacks_depth(bool totally_drain) { 209 totally_drain = totally_drain || _totally_drain; 210 211 #ifdef ASSERT 212 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 213 MutableSpace* to_space = heap->young_gen()->to_space(); 214 MutableSpace* old_space = heap->old_gen()->object_space(); 215 #endif /* ASSERT */ 216 217 OopStarTaskQueue* const tq = claimed_stack_depth(); 218 do { 219 StarTask p; 220 221 // Drain overflow stack first, so other threads can steal from 222 // claimed stack while we work. 223 while (tq->pop_overflow(p)) { 224 process_popped_location_depth(p); 225 } 226 227 if (totally_drain) { 228 while (tq->pop_local(p)) { 229 process_popped_location_depth(p); 230 } 231 } else { 232 while (tq->size() > _target_stack_size && tq->pop_local(p)) { 233 process_popped_location_depth(p); 234 } 235 } 236 } while (totally_drain && !tq->taskqueue_empty() || !tq->overflow_empty()); 237 238 assert(!totally_drain || tq->taskqueue_empty(), "Sanity"); 239 assert(totally_drain || tq->size() <= _target_stack_size, "Sanity"); 240 assert(tq->overflow_empty(), "Sanity"); 241 } 242 243 void PSPromotionManager::flush_labs() { 244 assert(stacks_empty(), "Attempt to flush lab with live stack"); 245 246 // If either promotion lab fills up, we can flush the 247 // lab but not refill it, so check first. 248 assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity"); 249 if (!_young_lab.is_flushed()) 250 _young_lab.flush(); 251 252 assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity"); 253 if (!_old_lab.is_flushed()) 254 _old_lab.flush(); 255 256 // Let PSScavenge know if we overflowed 257 if (_young_gen_is_full) { 258 PSScavenge::set_survivor_overflow(true); 259 } 260 } 261 262 template <class T> void PSPromotionManager::process_array_chunk_work( 263 oop obj, 264 int start, int end) { 265 assert(start <= end, "invariant"); 266 T* const base = (T*)objArrayOop(obj)->base(); 267 T* p = base + start; 268 T* const chunk_end = base + end; 269 while (p < chunk_end) { 270 if (PSScavenge::should_scavenge(p)) { 271 claim_or_forward_depth(p); 272 } 273 ++p; 274 } 275 } 276 277 void PSPromotionManager::process_array_chunk(oop old) { 278 assert(PSChunkLargeArrays, "invariant"); 279 assert(old->is_objArray(), "invariant"); 280 assert(old->is_forwarded(), "invariant"); 281 282 TASKQUEUE_STATS_ONLY(++_array_chunks_processed); 283 284 oop const obj = old->forwardee(); 285 286 int start; 287 int const end = arrayOop(old)->length(); 288 if (end > (int) _min_array_size_for_chunking) { 289 // we'll chunk more 290 start = end - _array_chunk_size; 291 assert(start > 0, "invariant"); 292 arrayOop(old)->set_length(start); 293 push_depth(mask_chunked_array_oop(old)); 294 TASKQUEUE_STATS_ONLY(++_masked_pushes); 295 } else { 296 // this is the final chunk for this array 297 start = 0; 298 int const actual_length = arrayOop(obj)->length(); 299 arrayOop(old)->set_length(actual_length); 300 } 301 302 if (UseCompressedOops) { 303 process_array_chunk_work<narrowOop>(obj, start, end); 304 } else { 305 process_array_chunk_work<oop>(obj, start, end); 306 } 307 } 308 309 class PushContentsClosure : public ExtendedOopClosure { 310 PSPromotionManager* _pm; 311 public: 312 PushContentsClosure(PSPromotionManager* pm) : _pm(pm) {} 313 314 template <typename T> void do_oop_nv(T* p) { 315 if (PSScavenge::should_scavenge(p)) { 316 _pm->claim_or_forward_depth(p); 317 } 318 } 319 320 virtual void do_oop(oop* p) { do_oop_nv(p); } 321 virtual void do_oop(narrowOop* p) { do_oop_nv(p); } 322 323 // Don't use the oop verification code in the oop_oop_iterate framework. 324 debug_only(virtual bool should_verify_oops() { return false; }) 325 }; 326 327 void InstanceKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) { 328 PushContentsClosure cl(pm); 329 oop_oop_iterate_oop_maps_reverse<true>(obj, &cl); 330 } 331 332 void InstanceMirrorKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) { 333 // Note that we don't have to follow the mirror -> klass pointer, since all 334 // klasses that are dirty will be scavenged when we iterate over the 335 // ClassLoaderData objects. 336 337 InstanceKlass::oop_ps_push_contents(obj, pm); 338 339 PushContentsClosure cl(pm); 340 oop_oop_iterate_statics<true>(obj, &cl); 341 } 342 343 void InstanceClassLoaderKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) { 344 InstanceKlass::oop_ps_push_contents(obj, pm); 345 346 // This is called by the young collector. It will already have taken care of 347 // all class loader data. So, we don't have to follow the class loader -> 348 // class loader data link. 349 } 350 351 template <class T> 352 static void oop_ps_push_contents_specialized(oop obj, InstanceRefKlass *klass, PSPromotionManager* pm) { 353 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj); 354 if (PSScavenge::should_scavenge(referent_addr)) { 355 ReferenceProcessor* rp = PSScavenge::reference_processor(); 356 if (rp->discover_reference(obj, klass->reference_type())) { 357 // reference already enqueued, referent and next will be traversed later 358 klass->InstanceKlass::oop_ps_push_contents(obj, pm); 359 return; 360 } else { 361 // treat referent as normal oop 362 pm->claim_or_forward_depth(referent_addr); 363 } 364 } 365 // Treat discovered as normal oop, if ref is not "active", 366 // i.e. if next is non-NULL. 367 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj); 368 T next_oop = oopDesc::load_heap_oop(next_addr); 369 if (!oopDesc::is_null(next_oop)) { // i.e. ref is not "active" 370 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj); 371 debug_only( 372 if(TraceReferenceGC && PrintGCDetails) { 373 gclog_or_tty->print_cr(" Process discovered as normal " 374 PTR_FORMAT, p2i(discovered_addr)); 375 } 376 ) 377 if (PSScavenge::should_scavenge(discovered_addr)) { 378 pm->claim_or_forward_depth(discovered_addr); 379 } 380 } 381 // Treat next as normal oop; next is a link in the reference queue. 382 if (PSScavenge::should_scavenge(next_addr)) { 383 pm->claim_or_forward_depth(next_addr); 384 } 385 klass->InstanceKlass::oop_ps_push_contents(obj, pm); 386 } 387 388 void InstanceRefKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) { 389 if (UseCompressedOops) { 390 oop_ps_push_contents_specialized<narrowOop>(obj, this, pm); 391 } else { 392 oop_ps_push_contents_specialized<oop>(obj, this, pm); 393 } 394 } 395 396 void ObjArrayKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) { 397 assert(obj->is_objArray(), "obj must be obj array"); 398 PushContentsClosure cl(pm); 399 oop_oop_iterate_elements<true>(objArrayOop(obj), &cl); 400 } 401 402 void TypeArrayKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) { 403 assert(obj->is_typeArray(),"must be a type array"); 404 ShouldNotReachHere(); 405 } 406 407 oop PSPromotionManager::oop_promotion_failed(oop obj, markOop obj_mark) { 408 assert(_old_gen_is_full || PromotionFailureALot, "Sanity"); 409 410 // Attempt to CAS in the header. 411 // This tests if the header is still the same as when 412 // this started. If it is the same (i.e., no forwarding 413 // pointer has been installed), then this thread owns 414 // it. 415 if (obj->cas_forward_to(obj, obj_mark)) { 416 // We won any races, we "own" this object. 417 assert(obj == obj->forwardee(), "Sanity"); 418 419 _promotion_failed_info.register_copy_failure(obj->size()); 420 421 push_contents(obj); 422 423 // Save the mark if needed 424 PSScavenge::oop_promotion_failed(obj, obj_mark); 425 } else { 426 // We lost, someone else "owns" this object 427 guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed."); 428 429 // No unallocation to worry about. 430 obj = obj->forwardee(); 431 } 432 433 if (TraceScavenge) { 434 gclog_or_tty->print_cr("{%s %s " PTR_FORMAT " (%d)}", 435 "promotion-failure", 436 obj->klass()->internal_name(), 437 p2i(obj), obj->size()); 438 439 } 440 441 return obj; 442 }