rev 58017 : [mq]: 8238854-remove-superfluous-alloc-checks

   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 
  64   _stack_array_depth = new OopStarTaskQueueSet(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, i, _masked_pushes, _masked_steals,
 138                 _arrays_chunked, _array_chunks_processed);
 139   #undef FMT
 140 }
 141 
 142 static const char* const pm_stats_hdr[] = {
 143   "    --------masked-------     arrays      array",
 144   "thr       push      steal    chunked     chunks",
 145   "--- ---------- ---------- ---------- ----------"
 146 };
 147 
 148 void
 149 PSPromotionManager::print_taskqueue_stats() {
 150   if (!log_is_enabled(Trace, gc, task, stats)) {
 151     return;
 152   }
 153   Log(gc, task, stats) log;
 154   ResourceMark rm;
 155   LogStream ls(log.trace());
 156   outputStream* out = &ls;
 157   out->print_cr("== GC Tasks Stats, GC %3d",
 158                 ParallelScavengeHeap::heap()->total_collections());
 159 
 160   TaskQueueStats totals;
 161   out->print("thr "); TaskQueueStats::print_header(1, out); out->cr();
 162   out->print("--- "); TaskQueueStats::print_header(2, out); out->cr();
 163   for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
 164     TaskQueueStats& next = manager_array(i)->_claimed_stack_depth.stats;
 165     out->print("%3d ", i); next.print(out); out->cr();
 166     totals += next;
 167   }
 168   out->print("tot "); totals.print(out); out->cr();
 169 
 170   const uint hlines = sizeof(pm_stats_hdr) / sizeof(pm_stats_hdr[0]);
 171   for (uint i = 0; i < hlines; ++i) out->print_cr("%s", pm_stats_hdr[i]);
 172   for (uint i = 0; i < ParallelGCThreads + 1; ++i) {
 173     manager_array(i)->print_local_stats(out, i);
 174   }
 175 }
 176 
 177 void
 178 PSPromotionManager::reset_stats() {
 179   claimed_stack_depth()->stats.reset();
 180   _masked_pushes = _masked_steals = 0;
 181   _arrays_chunked = _array_chunks_processed = 0;
 182 }
 183 #endif // TASKQUEUE_STATS
 184 
 185 PSPromotionManager::PSPromotionManager() {
 186   ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
 187 
 188   // We set the old lab's start array.
 189   _old_lab.set_start_array(old_gen()->start_array());
 190 
 191   uint queue_size;
 192   claimed_stack_depth()->initialize();
 193   queue_size = claimed_stack_depth()->max_elems();
 194 
 195   _totally_drain = (ParallelGCThreads == 1) || (GCDrainStackTargetSize == 0);
 196   if (_totally_drain) {
 197     _target_stack_size = 0;
 198   } else {
 199     // don't let the target stack size to be more than 1/4 of the entries
 200     _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize,
 201                                      (uint) (queue_size / 4));
 202   }
 203 
 204   _array_chunk_size = ParGCArrayScanChunk;
 205   // let's choose 1.5x the chunk size
 206   _min_array_size_for_chunking = 3 * _array_chunk_size / 2;
 207 
 208   _preserved_marks = NULL;
 209 
 210   reset();
 211 }
 212 
 213 void PSPromotionManager::reset() {
 214   assert(stacks_empty(), "reset of non-empty stack");
 215 
 216   // We need to get an assert in here to make sure the labs are always flushed.
 217 
 218   ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
 219 
 220   // Do not prefill the LAB's, save heap wastage!
 221   HeapWord* lab_base = young_space()->top();
 222   _young_lab.initialize(MemRegion(lab_base, (size_t)0));
 223   _young_gen_is_full = false;
 224 
 225   lab_base = old_gen()->object_space()->top();
 226   _old_lab.initialize(MemRegion(lab_base, (size_t)0));
 227   _old_gen_is_full = false;
 228 
 229   _promotion_failed_info.reset();
 230 
 231   TASKQUEUE_STATS_ONLY(reset_stats());
 232 }
 233 
 234 void PSPromotionManager::register_preserved_marks(PreservedMarks* preserved_marks) {
 235   assert(_preserved_marks == NULL, "do not set it twice");
 236   _preserved_marks = preserved_marks;
 237 }
 238 
 239 void PSPromotionManager::restore_preserved_marks() {
 240   _preserved_marks_set->restore(&ParallelScavengeHeap::heap()->workers());
 241 }
 242 
 243 void PSPromotionManager::drain_stacks_depth(bool totally_drain) {
 244   totally_drain = totally_drain || _totally_drain;
 245 
 246 #ifdef ASSERT
 247   ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
 248   MutableSpace* to_space = heap->young_gen()->to_space();
 249   MutableSpace* old_space = heap->old_gen()->object_space();
 250 #endif /* ASSERT */
 251 
 252   OopStarTaskQueue* const tq = claimed_stack_depth();
 253   do {
 254     StarTask p;
 255 
 256     // Drain overflow stack first, so other threads can steal from
 257     // claimed stack while we work.
 258     while (tq->pop_overflow(p)) {
 259       process_popped_location_depth(p);
 260     }
 261 
 262     if (totally_drain) {
 263       while (tq->pop_local(p)) {
 264         process_popped_location_depth(p);
 265       }
 266     } else {
 267       while (tq->size() > _target_stack_size && tq->pop_local(p)) {
 268         process_popped_location_depth(p);
 269       }
 270     }
 271   } while ((totally_drain && !tq->taskqueue_empty()) || !tq->overflow_empty());
 272 
 273   assert(!totally_drain || tq->taskqueue_empty(), "Sanity");
 274   assert(totally_drain || tq->size() <= _target_stack_size, "Sanity");
 275   assert(tq->overflow_empty(), "Sanity");
 276 }
 277 
 278 void PSPromotionManager::flush_labs() {
 279   assert(stacks_empty(), "Attempt to flush lab with live stack");
 280 
 281   // If either promotion lab fills up, we can flush the
 282   // lab but not refill it, so check first.
 283   assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity");
 284   if (!_young_lab.is_flushed())
 285     _young_lab.flush();
 286 
 287   assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity");
 288   if (!_old_lab.is_flushed())
 289     _old_lab.flush();
 290 
 291   // Let PSScavenge know if we overflowed
 292   if (_young_gen_is_full) {
 293     PSScavenge::set_survivor_overflow(true);
 294   }
 295 }
 296 
 297 template <class T> void PSPromotionManager::process_array_chunk_work(
 298                                                  oop obj,
 299                                                  int start, int end) {
 300   assert(start <= end, "invariant");
 301   T* const base      = (T*)objArrayOop(obj)->base();
 302   T* p               = base + start;
 303   T* const chunk_end = base + end;
 304   while (p < chunk_end) {
 305     if (PSScavenge::should_scavenge(p)) {
 306       claim_or_forward_depth(p);
 307     }
 308     ++p;
 309   }
 310 }
 311 
 312 void PSPromotionManager::process_array_chunk(oop old) {
 313   assert(PSChunkLargeArrays, "invariant");
 314   assert(old->is_objArray(), "invariant");
 315   assert(old->is_forwarded(), "invariant");
 316 
 317   TASKQUEUE_STATS_ONLY(++_array_chunks_processed);
 318 
 319   oop const obj = old->forwardee();
 320 
 321   int start;
 322   int const end = arrayOop(old)->length();
 323   if (end > (int) _min_array_size_for_chunking) {
 324     // we'll chunk more
 325     start = end - _array_chunk_size;
 326     assert(start > 0, "invariant");
 327     arrayOop(old)->set_length(start);
 328     push_depth(mask_chunked_array_oop(old));
 329     TASKQUEUE_STATS_ONLY(++_masked_pushes);
 330   } else {
 331     // this is the final chunk for this array
 332     start = 0;
 333     int const actual_length = arrayOop(obj)->length();
 334     arrayOop(old)->set_length(actual_length);
 335   }
 336 
 337   if (UseCompressedOops) {
 338     process_array_chunk_work<narrowOop>(obj, start, end);
 339   } else {
 340     process_array_chunk_work<oop>(obj, start, end);
 341   }
 342 }
 343 
 344 oop PSPromotionManager::oop_promotion_failed(oop obj, markWord obj_mark) {
 345   assert(_old_gen_is_full || PromotionFailureALot, "Sanity");
 346 
 347   // Attempt to CAS in the header.
 348   // This tests if the header is still the same as when
 349   // this started.  If it is the same (i.e., no forwarding
 350   // pointer has been installed), then this thread owns
 351   // it.
 352   if (obj->cas_forward_to(obj, obj_mark)) {
 353     // We won any races, we "own" this object.
 354     assert(obj == obj->forwardee(), "Sanity");
 355 
 356     _promotion_failed_info.register_copy_failure(obj->size());
 357 
 358     push_contents(obj);
 359 
 360     _preserved_marks->push_if_necessary(obj, obj_mark);
 361   }  else {
 362     // We lost, someone else "owns" this object
 363     guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed.");
 364 
 365     // No unallocation to worry about.
 366     obj = obj->forwardee();
 367   }
 368 
 369   log_develop_trace(gc, scavenge)("{promotion-failure %s " PTR_FORMAT " (%d)}", obj->klass()->internal_name(), p2i(obj), obj->size());
 370 
 371   return obj;
 372 }
--- EOF ---