1 /*
   2  * Copyright (c) 2001, 2016, 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/objectStartArray.inline.hpp"
  27 #include "gc/parallel/parallelScavengeHeap.hpp"
  28 #include "gc/parallel/psAdaptiveSizePolicy.hpp"
  29 #include "gc/parallel/psMarkSweepDecorator.hpp"
  30 #include "gc/parallel/psOldGen.hpp"
  31 #include "gc/shared/cardTableModRefBS.hpp"
  32 #include "gc/shared/gcLocker.inline.hpp"
  33 #include "gc/shared/spaceDecorator.hpp"
  34 #include "logging/log.hpp"
  35 #include "oops/oop.inline.hpp"
  36 #include "runtime/java.hpp"
  37 
  38 inline const char* PSOldGen::select_name() {
  39   return UseParallelOldGC ? "ParOldGen" : "PSOldGen";
  40 }
  41 
  42 PSOldGen::PSOldGen(ReservedSpace rs, size_t alignment,
  43                    size_t initial_size, size_t min_size, size_t max_size,
  44                    const char* perf_data_name, int level):
  45   _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
  46   _max_gen_size(max_size)
  47 {
  48   initialize(rs, alignment, perf_data_name, level);
  49 }
  50 
  51 PSOldGen::PSOldGen(size_t initial_size,
  52                    size_t min_size, size_t max_size,
  53                    const char* perf_data_name, int level):
  54   _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
  55   _max_gen_size(max_size)
  56 {}
  57 
  58 void PSOldGen::initialize(ReservedSpace rs, size_t alignment,
  59                           const char* perf_data_name, int level) {
  60   initialize_virtual_space(rs, alignment);
  61   initialize_work(perf_data_name, level);
  62 
  63   // The old gen can grow to gen_size_limit().  _reserve reflects only
  64   // the current maximum that can be committed.
  65   assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check");
  66 
  67   initialize_performance_counters(perf_data_name, level);
  68 }
  69 
  70 void PSOldGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {
  71 
  72   _virtual_space = new PSVirtualSpace(rs, alignment);
  73   if (!_virtual_space->expand_by(_init_gen_size)) {
  74     vm_exit_during_initialization("Could not reserve enough space for "
  75                                   "object heap");
  76   }
  77 }
  78 
  79 void PSOldGen::initialize_work(const char* perf_data_name, int level) {
  80   //
  81   // Basic memory initialization
  82   //
  83 
  84   MemRegion limit_reserved((HeapWord*)virtual_space()->low_boundary(),
  85     heap_word_size(_max_gen_size));
  86   assert(limit_reserved.byte_size() == _max_gen_size,
  87     "word vs bytes confusion");
  88   //
  89   // Object start stuff
  90   //
  91 
  92   start_array()->initialize(limit_reserved);
  93 
  94   _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
  95                         (HeapWord*)virtual_space()->high_boundary());
  96 
  97   //
  98   // Card table stuff
  99   //
 100 
 101   MemRegion cmr((HeapWord*)virtual_space()->low(),
 102                 (HeapWord*)virtual_space()->high());
 103   if (ZapUnusedHeapArea) {
 104     // Mangle newly committed space immediately rather than
 105     // waiting for the initialization of the space even though
 106     // mangling is related to spaces.  Doing it here eliminates
 107     // the need to carry along information that a complete mangling
 108     // (bottom to end) needs to be done.
 109     SpaceMangler::mangle_region(cmr);
 110   }
 111 
 112   ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
 113   BarrierSet* bs = heap->barrier_set();
 114 
 115   bs->resize_covered_region(cmr);
 116 
 117   CardTableModRefBS* ct = barrier_set_cast<CardTableModRefBS>(bs);
 118 
 119   // Verify that the start and end of this generation is the start of a card.
 120   // If this wasn't true, a single card could span more than one generation,
 121   // which would cause problems when we commit/uncommit memory, and when we
 122   // clear and dirty cards.
 123   guarantee(ct->is_card_aligned(_reserved.start()), "generation must be card aligned");
 124   if (_reserved.end() != heap->reserved_region().end()) {
 125     // Don't check at the very end of the heap as we'll assert that we're probing off
 126     // the end if we try.
 127     guarantee(ct->is_card_aligned(_reserved.end()), "generation must be card aligned");
 128   }
 129 
 130   //
 131   // ObjectSpace stuff
 132   //
 133 
 134   _object_space = new MutableSpace(virtual_space()->alignment());
 135 
 136   if (_object_space == NULL)
 137     vm_exit_during_initialization("Could not allocate an old gen space");
 138 
 139   object_space()->initialize(cmr,
 140                              SpaceDecorator::Clear,
 141                              SpaceDecorator::Mangle);
 142 
 143   _object_mark_sweep = new PSMarkSweepDecorator(_object_space, start_array(), MarkSweepDeadRatio);
 144 
 145   if (_object_mark_sweep == NULL)
 146     vm_exit_during_initialization("Could not complete allocation of old generation");
 147 
 148   // Update the start_array
 149   start_array()->set_covered_region(cmr);
 150 }
 151 
 152 void PSOldGen::initialize_performance_counters(const char* perf_data_name, int level) {
 153   // Generation Counters, generation 'level', 1 subspace
 154   _gen_counters = new PSGenerationCounters(perf_data_name, level, 1, _min_gen_size,
 155                                            _max_gen_size, virtual_space());
 156   _space_counters = new SpaceCounters(perf_data_name, 0,
 157                                       virtual_space()->reserved_size(),
 158                                       _object_space, _gen_counters);
 159 }
 160 
 161 // Assume that the generation has been allocated if its
 162 // reserved size is not 0.
 163 bool  PSOldGen::is_allocated() {
 164   return virtual_space()->reserved_size() != 0;
 165 }
 166 
 167 void PSOldGen::precompact() {
 168   ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
 169 
 170   // Reset start array first.
 171   start_array()->reset();
 172 
 173   object_mark_sweep()->precompact();
 174 
 175   // Now compact the young gen
 176   heap->young_gen()->precompact();
 177 }
 178 
 179 void PSOldGen::adjust_pointers() {
 180   object_mark_sweep()->adjust_pointers();
 181 }
 182 
 183 void PSOldGen::compact() {
 184   object_mark_sweep()->compact(ZapUnusedHeapArea);
 185 }
 186 
 187 size_t PSOldGen::contiguous_available() const {
 188   return object_space()->free_in_bytes() + virtual_space()->uncommitted_size();
 189 }
 190 
 191 // Allocation. We report all successful allocations to the size policy
 192 // Note that the perm gen does not use this method, and should not!
 193 HeapWord* PSOldGen::allocate(size_t word_size) {
 194   assert_locked_or_safepoint(Heap_lock);
 195   HeapWord* res = allocate_noexpand(word_size);
 196 
 197   if (res == NULL) {
 198     res = expand_and_allocate(word_size);
 199   }
 200 
 201   // Allocations in the old generation need to be reported
 202   if (res != NULL) {
 203     ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
 204     heap->size_policy()->tenured_allocation(word_size * HeapWordSize);
 205   }
 206 
 207   return res;
 208 }
 209 
 210 HeapWord* PSOldGen::expand_and_allocate(size_t word_size) {
 211   expand(word_size*HeapWordSize);
 212   if (GCExpandToAllocateDelayMillis > 0) {
 213     os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
 214   }
 215   return allocate_noexpand(word_size);
 216 }
 217 
 218 HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) {
 219   expand(word_size*HeapWordSize);
 220   if (GCExpandToAllocateDelayMillis > 0) {
 221     os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
 222   }
 223   return cas_allocate_noexpand(word_size);
 224 }
 225 
 226 void PSOldGen::expand(size_t bytes) {
 227   if (bytes == 0) {
 228     return;
 229   }
 230   MutexLocker x(ExpandHeap_lock);
 231   const size_t alignment = virtual_space()->alignment();
 232   size_t aligned_bytes  = align_size_up(bytes, alignment);
 233   size_t aligned_expand_bytes = align_size_up(MinHeapDeltaBytes, alignment);
 234 
 235   if (UseNUMA) {
 236     // With NUMA we use round-robin page allocation for the old gen. Expand by at least
 237     // providing a page per lgroup. Alignment is larger or equal to the page size.
 238     aligned_expand_bytes = MAX2(aligned_expand_bytes, alignment * os::numa_get_groups_num());
 239   }
 240   if (aligned_bytes == 0){
 241     // The alignment caused the number of bytes to wrap.  An expand_by(0) will
 242     // return true with the implication that and expansion was done when it
 243     // was not.  A call to expand implies a best effort to expand by "bytes"
 244     // but not a guarantee.  Align down to give a best effort.  This is likely
 245     // the most that the generation can expand since it has some capacity to
 246     // start with.
 247     aligned_bytes = align_size_down(bytes, alignment);
 248   }
 249 
 250   bool success = false;
 251   if (aligned_expand_bytes > aligned_bytes) {
 252     success = expand_by(aligned_expand_bytes);
 253   }
 254   if (!success) {
 255     success = expand_by(aligned_bytes);
 256   }
 257   if (!success) {
 258     success = expand_to_reserved();
 259   }
 260 
 261   if (success && GCLocker::is_active_and_needs_gc()) {
 262     log_debug(gc)("Garbage collection disabled, expanded heap instead");
 263   }
 264 }
 265 
 266 bool PSOldGen::expand_by(size_t bytes) {
 267   assert_lock_strong(ExpandHeap_lock);
 268   assert_locked_or_safepoint(Heap_lock);
 269   if (bytes == 0) {
 270     return true;  // That's what virtual_space()->expand_by(0) would return
 271   }
 272   bool result = virtual_space()->expand_by(bytes);
 273   if (result) {
 274     if (ZapUnusedHeapArea) {
 275       // We need to mangle the newly expanded area. The memregion spans
 276       // end -> new_end, we assume that top -> end is already mangled.
 277       // Do the mangling before post_resize() is called because
 278       // the space is available for allocation after post_resize();
 279       HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high();
 280       assert(object_space()->end() < virtual_space_high,
 281         "Should be true before post_resize()");
 282       MemRegion mangle_region(object_space()->end(), virtual_space_high);
 283       // Note that the object space has not yet been updated to
 284       // coincide with the new underlying virtual space.
 285       SpaceMangler::mangle_region(mangle_region);
 286     }
 287     post_resize();
 288     if (UsePerfData) {
 289       _space_counters->update_capacity();
 290       _gen_counters->update_all();
 291     }
 292   }
 293 
 294   if (result) {
 295     size_t new_mem_size = virtual_space()->committed_size();
 296     size_t old_mem_size = new_mem_size - bytes;
 297     log_debug(gc)("Expanding %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
 298                   name(), old_mem_size/K, bytes/K, new_mem_size/K);
 299   }
 300 
 301   return result;
 302 }
 303 
 304 bool PSOldGen::expand_to_reserved() {
 305   assert_lock_strong(ExpandHeap_lock);
 306   assert_locked_or_safepoint(Heap_lock);
 307 
 308   bool result = true;
 309   const size_t remaining_bytes = virtual_space()->uncommitted_size();
 310   if (remaining_bytes > 0) {
 311     result = expand_by(remaining_bytes);
 312     DEBUG_ONLY(if (!result) warning("grow to reserve failed"));
 313   }
 314   return result;
 315 }
 316 
 317 void PSOldGen::shrink(size_t bytes) {
 318   assert_lock_strong(ExpandHeap_lock);
 319   assert_locked_or_safepoint(Heap_lock);
 320 
 321   size_t size = align_size_down(bytes, virtual_space()->alignment());
 322   if (size > 0) {
 323     assert_lock_strong(ExpandHeap_lock);
 324     virtual_space()->shrink_by(bytes);
 325     post_resize();
 326 
 327     size_t new_mem_size = virtual_space()->committed_size();
 328     size_t old_mem_size = new_mem_size + bytes;
 329     log_debug(gc)("Shrinking %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
 330                   name(), old_mem_size/K, bytes/K, new_mem_size/K);
 331   }
 332 }
 333 
 334 void PSOldGen::resize(size_t desired_free_space) {
 335   const size_t alignment = virtual_space()->alignment();
 336   const size_t size_before = virtual_space()->committed_size();
 337   size_t new_size = used_in_bytes() + desired_free_space;
 338   if (new_size < used_in_bytes()) {
 339     // Overflowed the addition.
 340     new_size = gen_size_limit();
 341   }
 342   // Adjust according to our min and max
 343   new_size = MAX2(MIN2(new_size, gen_size_limit()), min_gen_size());
 344 
 345   assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?");
 346   new_size = align_size_up(new_size, alignment);
 347 
 348   const size_t current_size = capacity_in_bytes();
 349 
 350   log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: "
 351     "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT
 352     " new size: " SIZE_FORMAT " current size " SIZE_FORMAT
 353     " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
 354     desired_free_space, used_in_bytes(), new_size, current_size,
 355     gen_size_limit(), min_gen_size());
 356 
 357   if (new_size == current_size) {
 358     // No change requested
 359     return;
 360   }
 361   if (new_size > current_size) {
 362     size_t change_bytes = new_size - current_size;
 363     expand(change_bytes);
 364   } else {
 365     size_t change_bytes = current_size - new_size;
 366     // shrink doesn't grab this lock, expand does. Is that right?
 367     MutexLocker x(ExpandHeap_lock);
 368     shrink(change_bytes);
 369   }
 370 
 371   log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: collection: %d (" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",
 372                       ParallelScavengeHeap::heap()->total_collections(),
 373                       size_before,
 374                       virtual_space()->committed_size());
 375 }
 376 
 377 // NOTE! We need to be careful about resizing. During a GC, multiple
 378 // allocators may be active during heap expansion. If we allow the
 379 // heap resizing to become visible before we have correctly resized
 380 // all heap related data structures, we may cause program failures.
 381 void PSOldGen::post_resize() {
 382   // First construct a memregion representing the new size
 383   MemRegion new_memregion((HeapWord*)virtual_space()->low(),
 384     (HeapWord*)virtual_space()->high());
 385   size_t new_word_size = new_memregion.word_size();
 386 
 387   start_array()->set_covered_region(new_memregion);
 388   ParallelScavengeHeap::heap()->barrier_set()->resize_covered_region(new_memregion);
 389 
 390   // ALWAYS do this last!!
 391   object_space()->initialize(new_memregion,
 392                              SpaceDecorator::DontClear,
 393                              SpaceDecorator::DontMangle);
 394 
 395   assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()),
 396     "Sanity");
 397 }
 398 
 399 size_t PSOldGen::gen_size_limit() {
 400   return _max_gen_size;
 401 }
 402 
 403 void PSOldGen::reset_after_change() {
 404   ShouldNotReachHere();
 405   return;
 406 }
 407 
 408 size_t PSOldGen::available_for_expansion() {
 409   ShouldNotReachHere();
 410   return 0;
 411 }
 412 
 413 size_t PSOldGen::available_for_contraction() {
 414   ShouldNotReachHere();
 415   return 0;
 416 }
 417 
 418 void PSOldGen::print() const { print_on(tty);}
 419 void PSOldGen::print_on(outputStream* st) const {
 420   st->print(" %-15s", name());
 421   st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
 422               capacity_in_bytes()/K, used_in_bytes()/K);
 423   st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
 424                 p2i(virtual_space()->low_boundary()),
 425                 p2i(virtual_space()->high()),
 426                 p2i(virtual_space()->high_boundary()));
 427 
 428   st->print("  object"); object_space()->print_on(st);
 429 }
 430 
 431 void PSOldGen::print_used_change(size_t prev_used) const {
 432   log_info(gc, heap)("%s: "  SIZE_FORMAT "K->" SIZE_FORMAT "K("  SIZE_FORMAT "K)",
 433       name(), prev_used / K, used_in_bytes() / K, capacity_in_bytes() / K);
 434 }
 435 
 436 void PSOldGen::update_counters() {
 437   if (UsePerfData) {
 438     _space_counters->update_all();
 439     _gen_counters->update_all();
 440   }
 441 }
 442 
 443 #ifndef PRODUCT
 444 
 445 void PSOldGen::space_invariants() {
 446   assert(object_space()->end() == (HeapWord*) virtual_space()->high(),
 447     "Space invariant");
 448   assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(),
 449     "Space invariant");
 450   assert(virtual_space()->low_boundary() <= virtual_space()->low(),
 451     "Space invariant");
 452   assert(virtual_space()->high_boundary() >= virtual_space()->high(),
 453     "Space invariant");
 454   assert(virtual_space()->low_boundary() == (char*) _reserved.start(),
 455     "Space invariant");
 456   assert(virtual_space()->high_boundary() == (char*) _reserved.end(),
 457     "Space invariant");
 458   assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
 459     "Space invariant");
 460 }
 461 #endif
 462 
 463 void PSOldGen::verify() {
 464   object_space()->verify();
 465 }
 466 class VerifyObjectStartArrayClosure : public ObjectClosure {
 467   PSOldGen* _old_gen;
 468   ObjectStartArray* _start_array;
 469 
 470  public:
 471   VerifyObjectStartArrayClosure(PSOldGen* old_gen, ObjectStartArray* start_array) :
 472     _old_gen(old_gen), _start_array(start_array) { }
 473 
 474   virtual void do_object(oop obj) {
 475     HeapWord* test_addr = (HeapWord*)obj + 1;
 476     guarantee(_start_array->object_start(test_addr) == (HeapWord*)obj, "ObjectStartArray cannot find start of object");
 477     guarantee(_start_array->is_block_allocated((HeapWord*)obj), "ObjectStartArray missing block allocation");
 478   }
 479 };
 480 
 481 void PSOldGen::verify_object_start_array() {
 482   VerifyObjectStartArrayClosure check( this, &_start_array );
 483   object_iterate(&check);
 484 }
 485 
 486 #ifndef PRODUCT
 487 void PSOldGen::record_spaces_top() {
 488   assert(ZapUnusedHeapArea, "Not mangling unused space");
 489   object_space()->set_top_for_allocations();
 490 }
 491 #endif