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





 379     if (PSScavenge::should_scavenge(discovered_addr)) {
 380       pm->claim_or_forward_depth(discovered_addr);
 381     }
 382   }
 383   // Treat next as normal oop;  next is a link in the reference queue.
 384   if (PSScavenge::should_scavenge(next_addr)) {
 385     pm->claim_or_forward_depth(next_addr);
 386   }
 387   klass->InstanceKlass::oop_ps_push_contents(obj, pm);
 388 }
 389 
 390 void InstanceRefKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
 391   if (UseCompressedOops) {
 392     oop_ps_push_contents_specialized<narrowOop>(obj, this, pm);
 393   } else {
 394     oop_ps_push_contents_specialized<oop>(obj, this, pm);
 395   }
 396 }
 397 
 398 void ObjArrayKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
 399   assert(obj->is_objArray(), "obj must be obj array");
 400   PushContentsClosure cl(pm);
 401   oop_oop_iterate_elements<true>(objArrayOop(obj), &cl);
 402 }
 403 
 404 void TypeArrayKlass::oop_ps_push_contents(oop obj, PSPromotionManager* pm) {
 405   assert(obj->is_typeArray(),"must be a type array");
 406   ShouldNotReachHere();
 407 }
 408 
 409 oop PSPromotionManager::oop_promotion_failed(oop obj, markOop obj_mark) {
 410   assert(_old_gen_is_full || PromotionFailureALot, "Sanity");
 411 
 412   // Attempt to CAS in the header.
 413   // This tests if the header is still the same as when
 414   // this started.  If it is the same (i.e., no forwarding
 415   // pointer has been installed), then this thread owns
 416   // it.
 417   if (obj->cas_forward_to(obj, obj_mark)) {
 418     // We won any races, we "own" this object.
 419     assert(obj == obj->forwardee(), "Sanity");
 420 
 421     _promotion_failed_info.register_copy_failure(obj->size());
 422 
 423     push_contents(obj);
 424 
 425     // Save the mark if needed
 426     PSScavenge::oop_promotion_failed(obj, obj_mark);
 427   }  else {
 428     // We lost, someone else "owns" this object
 429     guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed.");
 430 
 431     // No unallocation to worry about.
 432     obj = obj->forwardee();
 433   }
 434 
 435   log_develop(gc, scavenge)("{promotion-failure %s " PTR_FORMAT " (%d)}", obj->klass()->internal_name(), p2i(obj), obj->size());








 436 
 437   return obj;
 438 }
--- EOF ---