rev 5350 : 8025313: MetaspaceMemoryPool incorrectly reports undefined size for max

   1 /*
   2  * Copyright (c) 2001, 2013, 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_implementation/shared/adaptiveSizePolicy.hpp"
  27 #include "gc_implementation/shared/gcPolicyCounters.hpp"
  28 #include "gc_implementation/shared/vmGCOperations.hpp"
  29 #include "memory/cardTableRS.hpp"
  30 #include "memory/collectorPolicy.hpp"
  31 #include "memory/gcLocker.inline.hpp"
  32 #include "memory/genCollectedHeap.hpp"
  33 #include "memory/generationSpec.hpp"
  34 #include "memory/space.hpp"
  35 #include "memory/universe.hpp"
  36 #include "runtime/arguments.hpp"
  37 #include "runtime/globals_extension.hpp"
  38 #include "runtime/handles.inline.hpp"
  39 #include "runtime/java.hpp"
  40 #include "runtime/thread.inline.hpp"
  41 #include "runtime/vmThread.hpp"
  42 #include "utilities/macros.hpp"
  43 #if INCLUDE_ALL_GCS
  44 #include "gc_implementation/concurrentMarkSweep/cmsAdaptiveSizePolicy.hpp"
  45 #include "gc_implementation/concurrentMarkSweep/cmsGCAdaptivePolicyCounters.hpp"
  46 #endif // INCLUDE_ALL_GCS
  47 
  48 // CollectorPolicy methods.
  49 
  50 // Align down. If the aligning result in 0, return 'alignment'.
  51 static size_t restricted_align_down(size_t size, size_t alignment) {
  52   return MAX2(alignment, align_size_down_(size, alignment));
  53 }
  54 
  55 void CollectorPolicy::initialize_flags() {
  56   assert(max_alignment() >= min_alignment(),
  57       err_msg("max_alignment: " SIZE_FORMAT " less than min_alignment: " SIZE_FORMAT,
  58           max_alignment(), min_alignment()));
  59   assert(max_alignment() % min_alignment() == 0,
  60       err_msg("max_alignment: " SIZE_FORMAT " not aligned by min_alignment: " SIZE_FORMAT,
  61           max_alignment(), min_alignment()));
  62 
  63   if (MaxHeapSize < InitialHeapSize) {
  64     vm_exit_during_initialization("Incompatible initial and maximum heap sizes specified");
  65   }
  66 
  67   if (!is_size_aligned(MaxMetaspaceSize, max_alignment())) {
  68     MaxMetaspaceSize = restricted_align_down(MaxMetaspaceSize, max_alignment());

  69   }
  70 
  71   if (MetaspaceSize > MaxMetaspaceSize) {
  72     FLAG_SET_ERGO(uintx, MetaspaceSize, MaxMetaspaceSize);
  73   }
  74 
  75   if (!is_size_aligned(MetaspaceSize, min_alignment())) {
  76     FLAG_SET_ERGO(uintx, MetaspaceSize,
  77         restricted_align_down(MetaspaceSize, min_alignment()));
  78   }
  79 
  80   assert(MetaspaceSize <= MaxMetaspaceSize, "Must be");
  81 
  82   MinMetaspaceExpansion = restricted_align_down(MinMetaspaceExpansion, min_alignment());
  83   MaxMetaspaceExpansion = restricted_align_down(MaxMetaspaceExpansion, min_alignment());
  84 
  85   MinHeapDeltaBytes = align_size_up(MinHeapDeltaBytes, min_alignment());
  86 
  87   assert(MetaspaceSize    % min_alignment() == 0, "metapace alignment");
  88   assert(MaxMetaspaceSize % max_alignment() == 0, "maximum metaspace alignment");
  89   if (MetaspaceSize < 256*K) {
  90     vm_exit_during_initialization("Too small initial Metaspace size");
  91   }
  92 }
  93 
  94 void CollectorPolicy::initialize_size_info() {
  95   // User inputs from -mx and ms must be aligned
  96   set_min_heap_byte_size(align_size_up(Arguments::min_heap_size(), min_alignment()));
  97   set_initial_heap_byte_size(align_size_up(InitialHeapSize, min_alignment()));
  98   set_max_heap_byte_size(align_size_up(MaxHeapSize, max_alignment()));
  99 
 100   // Check heap parameter properties
 101   if (initial_heap_byte_size() < M) {
 102     vm_exit_during_initialization("Too small initial heap");
 103   }
 104   // Check heap parameter properties
 105   if (min_heap_byte_size() < M) {
 106     vm_exit_during_initialization("Too small minimum heap");
 107   }
 108   if (initial_heap_byte_size() <= NewSize) {
 109      // make sure there is at least some room in old space
 110     vm_exit_during_initialization("Too small initial heap for new size specified");
 111   }
 112   if (max_heap_byte_size() < min_heap_byte_size()) {
 113     vm_exit_during_initialization("Incompatible minimum and maximum heap sizes specified");
 114   }
 115   if (initial_heap_byte_size() < min_heap_byte_size()) {
 116     vm_exit_during_initialization("Incompatible minimum and initial heap sizes specified");
 117   }
 118   if (max_heap_byte_size() < initial_heap_byte_size()) {
 119     vm_exit_during_initialization("Incompatible initial and maximum heap sizes specified");
 120   }
 121 
 122   if (PrintGCDetails && Verbose) {
 123     gclog_or_tty->print_cr("Minimum heap " SIZE_FORMAT "  Initial heap "
 124       SIZE_FORMAT "  Maximum heap " SIZE_FORMAT,
 125       min_heap_byte_size(), initial_heap_byte_size(), max_heap_byte_size());
 126   }
 127 }
 128 
 129 bool CollectorPolicy::use_should_clear_all_soft_refs(bool v) {
 130   bool result = _should_clear_all_soft_refs;
 131   set_should_clear_all_soft_refs(false);
 132   return result;
 133 }
 134 
 135 GenRemSet* CollectorPolicy::create_rem_set(MemRegion whole_heap,
 136                                            int max_covered_regions) {
 137   switch (rem_set_name()) {
 138   case GenRemSet::CardTable: {
 139     CardTableRS* res = new CardTableRS(whole_heap, max_covered_regions);
 140     return res;
 141   }
 142   default:
 143     guarantee(false, "unrecognized GenRemSet::Name");
 144     return NULL;
 145   }
 146 }
 147 
 148 void CollectorPolicy::cleared_all_soft_refs() {
 149   // If near gc overhear limit, continue to clear SoftRefs.  SoftRefs may
 150   // have been cleared in the last collection but if the gc overhear
 151   // limit continues to be near, SoftRefs should still be cleared.
 152   if (size_policy() != NULL) {
 153     _should_clear_all_soft_refs = size_policy()->gc_overhead_limit_near();
 154   }
 155   _all_soft_refs_clear = true;
 156 }
 157 
 158 size_t CollectorPolicy::compute_max_alignment() {
 159   // The card marking array and the offset arrays for old generations are
 160   // committed in os pages as well. Make sure they are entirely full (to
 161   // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1
 162   // byte entry and the os page size is 4096, the maximum heap size should
 163   // be 512*4096 = 2MB aligned.
 164 
 165   // There is only the GenRemSet in Hotspot and only the GenRemSet::CardTable
 166   // is supported.
 167   // Requirements of any new remembered set implementations must be added here.
 168   size_t alignment = GenRemSet::max_alignment_constraint(GenRemSet::CardTable);
 169 
 170   // Parallel GC does its own alignment of the generations to avoid requiring a
 171   // large page (256M on some platforms) for the permanent generation.  The
 172   // other collectors should also be updated to do their own alignment and then
 173   // this use of lcm() should be removed.
 174   if (UseLargePages && !UseParallelGC) {
 175       // in presence of large pages we have to make sure that our
 176       // alignment is large page aware
 177       alignment = lcm(os::large_page_size(), alignment);
 178   }
 179 
 180   return alignment;
 181 }
 182 
 183 // GenCollectorPolicy methods.
 184 
 185 size_t GenCollectorPolicy::scale_by_NewRatio_aligned(size_t base_size) {
 186   size_t x = base_size / (NewRatio+1);
 187   size_t new_gen_size = x > min_alignment() ?
 188                      align_size_down(x, min_alignment()) :
 189                      min_alignment();
 190   return new_gen_size;
 191 }
 192 
 193 size_t GenCollectorPolicy::bound_minus_alignment(size_t desired_size,
 194                                                  size_t maximum_size) {
 195   size_t alignment = min_alignment();
 196   size_t max_minus = maximum_size - alignment;
 197   return desired_size < max_minus ? desired_size : max_minus;
 198 }
 199 
 200 
 201 void GenCollectorPolicy::initialize_size_policy(size_t init_eden_size,
 202                                                 size_t init_promo_size,
 203                                                 size_t init_survivor_size) {
 204   const double max_gc_pause_sec = ((double) MaxGCPauseMillis)/1000.0;
 205   _size_policy = new AdaptiveSizePolicy(init_eden_size,
 206                                         init_promo_size,
 207                                         init_survivor_size,
 208                                         max_gc_pause_sec,
 209                                         GCTimeRatio);
 210 }
 211 
 212 void GenCollectorPolicy::initialize_flags() {
 213   // All sizes must be multiples of the generation granularity.
 214   set_min_alignment((uintx) Generation::GenGrain);
 215   set_max_alignment(compute_max_alignment());
 216 
 217   CollectorPolicy::initialize_flags();
 218 
 219   // All generational heaps have a youngest gen; handle those flags here.
 220 
 221   // Adjust max size parameters
 222   if (NewSize > MaxNewSize) {
 223     MaxNewSize = NewSize;
 224   }
 225   NewSize = align_size_down(NewSize, min_alignment());
 226   MaxNewSize = align_size_down(MaxNewSize, min_alignment());
 227 
 228   // Check validity of heap flags
 229   assert(NewSize     % min_alignment() == 0, "eden space alignment");
 230   assert(MaxNewSize  % min_alignment() == 0, "survivor space alignment");
 231 
 232   if (NewSize < 3*min_alignment()) {
 233      // make sure there room for eden and two survivor spaces
 234     vm_exit_during_initialization("Too small new size specified");
 235   }
 236   if (SurvivorRatio < 1 || NewRatio < 1) {
 237     vm_exit_during_initialization("Invalid heap ratio specified");
 238   }
 239 }
 240 
 241 void TwoGenerationCollectorPolicy::initialize_flags() {
 242   GenCollectorPolicy::initialize_flags();
 243 
 244   OldSize = align_size_down(OldSize, min_alignment());
 245 
 246   if (FLAG_IS_CMDLINE(OldSize) && FLAG_IS_DEFAULT(NewSize)) {
 247     // NewRatio will be used later to set the young generation size so we use
 248     // it to calculate how big the heap should be based on the requested OldSize
 249     // and NewRatio.
 250     assert(NewRatio > 0, "NewRatio should have been set up earlier");
 251     size_t calculated_heapsize = (OldSize / NewRatio) * (NewRatio + 1);
 252 
 253     calculated_heapsize = align_size_up(calculated_heapsize, max_alignment());
 254     MaxHeapSize = calculated_heapsize;
 255     InitialHeapSize = calculated_heapsize;
 256   }
 257   MaxHeapSize = align_size_up(MaxHeapSize, max_alignment());
 258 
 259   // adjust max heap size if necessary
 260   if (NewSize + OldSize > MaxHeapSize) {
 261     if (FLAG_IS_CMDLINE(MaxHeapSize)) {
 262       // somebody set a maximum heap size with the intention that we should not
 263       // exceed it. Adjust New/OldSize as necessary.
 264       uintx calculated_size = NewSize + OldSize;
 265       double shrink_factor = (double) MaxHeapSize / calculated_size;
 266       // align
 267       NewSize = align_size_down((uintx) (NewSize * shrink_factor), min_alignment());
 268       // OldSize is already aligned because above we aligned MaxHeapSize to
 269       // max_alignment(), and we just made sure that NewSize is aligned to
 270       // min_alignment(). In initialize_flags() we verified that max_alignment()
 271       // is a multiple of min_alignment().
 272       OldSize = MaxHeapSize - NewSize;
 273     } else {
 274       MaxHeapSize = NewSize + OldSize;
 275     }
 276   }
 277   // need to do this again
 278   MaxHeapSize = align_size_up(MaxHeapSize, max_alignment());
 279 
 280   // adjust max heap size if necessary
 281   if (NewSize + OldSize > MaxHeapSize) {
 282     if (FLAG_IS_CMDLINE(MaxHeapSize)) {
 283       // somebody set a maximum heap size with the intention that we should not
 284       // exceed it. Adjust New/OldSize as necessary.
 285       uintx calculated_size = NewSize + OldSize;
 286       double shrink_factor = (double) MaxHeapSize / calculated_size;
 287       // align
 288       NewSize = align_size_down((uintx) (NewSize * shrink_factor), min_alignment());
 289       // OldSize is already aligned because above we aligned MaxHeapSize to
 290       // max_alignment(), and we just made sure that NewSize is aligned to
 291       // min_alignment(). In initialize_flags() we verified that max_alignment()
 292       // is a multiple of min_alignment().
 293       OldSize = MaxHeapSize - NewSize;
 294     } else {
 295       MaxHeapSize = NewSize + OldSize;
 296     }
 297   }
 298   // need to do this again
 299   MaxHeapSize = align_size_up(MaxHeapSize, max_alignment());
 300 
 301   always_do_update_barrier = UseConcMarkSweepGC;
 302 
 303   // Check validity of heap flags
 304   assert(OldSize     % min_alignment() == 0, "old space alignment");
 305   assert(MaxHeapSize % max_alignment() == 0, "maximum heap alignment");
 306 }
 307 
 308 // Values set on the command line win over any ergonomically
 309 // set command line parameters.
 310 // Ergonomic choice of parameters are done before this
 311 // method is called.  Values for command line parameters such as NewSize
 312 // and MaxNewSize feed those ergonomic choices into this method.
 313 // This method makes the final generation sizings consistent with
 314 // themselves and with overall heap sizings.
 315 // In the absence of explicitly set command line flags, policies
 316 // such as the use of NewRatio are used to size the generation.
 317 void GenCollectorPolicy::initialize_size_info() {
 318   CollectorPolicy::initialize_size_info();
 319 
 320   // min_alignment() is used for alignment within a generation.
 321   // There is additional alignment done down stream for some
 322   // collectors that sometimes causes unwanted rounding up of
 323   // generations sizes.
 324 
 325   // Determine maximum size of gen0
 326 
 327   size_t max_new_size = 0;
 328   if (FLAG_IS_CMDLINE(MaxNewSize) || FLAG_IS_ERGO(MaxNewSize)) {
 329     if (MaxNewSize < min_alignment()) {
 330       max_new_size = min_alignment();
 331     }
 332     if (MaxNewSize >= max_heap_byte_size()) {
 333       max_new_size = align_size_down(max_heap_byte_size() - min_alignment(),
 334                                      min_alignment());
 335       warning("MaxNewSize (" SIZE_FORMAT "k) is equal to or "
 336         "greater than the entire heap (" SIZE_FORMAT "k).  A "
 337         "new generation size of " SIZE_FORMAT "k will be used.",
 338         MaxNewSize/K, max_heap_byte_size()/K, max_new_size/K);
 339     } else {
 340       max_new_size = align_size_down(MaxNewSize, min_alignment());
 341     }
 342 
 343   // The case for FLAG_IS_ERGO(MaxNewSize) could be treated
 344   // specially at this point to just use an ergonomically set
 345   // MaxNewSize to set max_new_size.  For cases with small
 346   // heaps such a policy often did not work because the MaxNewSize
 347   // was larger than the entire heap.  The interpretation given
 348   // to ergonomically set flags is that the flags are set
 349   // by different collectors for their own special needs but
 350   // are not allowed to badly shape the heap.  This allows the
 351   // different collectors to decide what's best for themselves
 352   // without having to factor in the overall heap shape.  It
 353   // can be the case in the future that the collectors would
 354   // only make "wise" ergonomics choices and this policy could
 355   // just accept those choices.  The choices currently made are
 356   // not always "wise".
 357   } else {
 358     max_new_size = scale_by_NewRatio_aligned(max_heap_byte_size());
 359     // Bound the maximum size by NewSize below (since it historically
 360     // would have been NewSize and because the NewRatio calculation could
 361     // yield a size that is too small) and bound it by MaxNewSize above.
 362     // Ergonomics plays here by previously calculating the desired
 363     // NewSize and MaxNewSize.
 364     max_new_size = MIN2(MAX2(max_new_size, NewSize), MaxNewSize);
 365   }
 366   assert(max_new_size > 0, "All paths should set max_new_size");
 367 
 368   // Given the maximum gen0 size, determine the initial and
 369   // minimum gen0 sizes.
 370 
 371   if (max_heap_byte_size() == min_heap_byte_size()) {
 372     // The maximum and minimum heap sizes are the same so
 373     // the generations minimum and initial must be the
 374     // same as its maximum.
 375     set_min_gen0_size(max_new_size);
 376     set_initial_gen0_size(max_new_size);
 377     set_max_gen0_size(max_new_size);
 378   } else {
 379     size_t desired_new_size = 0;
 380     if (!FLAG_IS_DEFAULT(NewSize)) {
 381       // If NewSize is set ergonomically (for example by cms), it
 382       // would make sense to use it.  If it is used, also use it
 383       // to set the initial size.  Although there is no reason
 384       // the minimum size and the initial size have to be the same,
 385       // the current implementation gets into trouble during the calculation
 386       // of the tenured generation sizes if they are different.
 387       // Note that this makes the initial size and the minimum size
 388       // generally small compared to the NewRatio calculation.
 389       _min_gen0_size = NewSize;
 390       desired_new_size = NewSize;
 391       max_new_size = MAX2(max_new_size, NewSize);
 392     } else {
 393       // For the case where NewSize is the default, use NewRatio
 394       // to size the minimum and initial generation sizes.
 395       // Use the default NewSize as the floor for these values.  If
 396       // NewRatio is overly large, the resulting sizes can be too
 397       // small.
 398       _min_gen0_size = MAX2(scale_by_NewRatio_aligned(min_heap_byte_size()),
 399                           NewSize);
 400       desired_new_size =
 401         MAX2(scale_by_NewRatio_aligned(initial_heap_byte_size()),
 402              NewSize);
 403     }
 404 
 405     assert(_min_gen0_size > 0, "Sanity check");
 406     set_initial_gen0_size(desired_new_size);
 407     set_max_gen0_size(max_new_size);
 408 
 409     // At this point the desirable initial and minimum sizes have been
 410     // determined without regard to the maximum sizes.
 411 
 412     // Bound the sizes by the corresponding overall heap sizes.
 413     set_min_gen0_size(
 414       bound_minus_alignment(_min_gen0_size, min_heap_byte_size()));
 415     set_initial_gen0_size(
 416       bound_minus_alignment(_initial_gen0_size, initial_heap_byte_size()));
 417     set_max_gen0_size(
 418       bound_minus_alignment(_max_gen0_size, max_heap_byte_size()));
 419 
 420     // At this point all three sizes have been checked against the
 421     // maximum sizes but have not been checked for consistency
 422     // among the three.
 423 
 424     // Final check min <= initial <= max
 425     set_min_gen0_size(MIN2(_min_gen0_size, _max_gen0_size));
 426     set_initial_gen0_size(
 427       MAX2(MIN2(_initial_gen0_size, _max_gen0_size), _min_gen0_size));
 428     set_min_gen0_size(MIN2(_min_gen0_size, _initial_gen0_size));
 429   }
 430 
 431   if (PrintGCDetails && Verbose) {
 432     gclog_or_tty->print_cr("1: Minimum gen0 " SIZE_FORMAT "  Initial gen0 "
 433       SIZE_FORMAT "  Maximum gen0 " SIZE_FORMAT,
 434       min_gen0_size(), initial_gen0_size(), max_gen0_size());
 435   }
 436 }
 437 
 438 // Call this method during the sizing of the gen1 to make
 439 // adjustments to gen0 because of gen1 sizing policy.  gen0 initially has
 440 // the most freedom in sizing because it is done before the
 441 // policy for gen1 is applied.  Once gen1 policies have been applied,
 442 // there may be conflicts in the shape of the heap and this method
 443 // is used to make the needed adjustments.  The application of the
 444 // policies could be more sophisticated (iterative for example) but
 445 // keeping it simple also seems a worthwhile goal.
 446 bool TwoGenerationCollectorPolicy::adjust_gen0_sizes(size_t* gen0_size_ptr,
 447                                                      size_t* gen1_size_ptr,
 448                                                      const size_t heap_size,
 449                                                      const size_t min_gen1_size) {
 450   bool result = false;
 451 
 452   if ((*gen1_size_ptr + *gen0_size_ptr) > heap_size) {
 453     if ((heap_size < (*gen0_size_ptr + min_gen1_size)) &&
 454         (heap_size >= min_gen1_size + min_alignment())) {
 455       // Adjust gen0 down to accommodate min_gen1_size
 456       *gen0_size_ptr = heap_size - min_gen1_size;
 457       *gen0_size_ptr =
 458         MAX2((uintx)align_size_down(*gen0_size_ptr, min_alignment()),
 459              min_alignment());
 460       assert(*gen0_size_ptr > 0, "Min gen0 is too large");
 461       result = true;
 462     } else {
 463       *gen1_size_ptr = heap_size - *gen0_size_ptr;
 464       *gen1_size_ptr =
 465         MAX2((uintx)align_size_down(*gen1_size_ptr, min_alignment()),
 466                        min_alignment());
 467     }
 468   }
 469   return result;
 470 }
 471 
 472 // Minimum sizes of the generations may be different than
 473 // the initial sizes.  An inconsistently is permitted here
 474 // in the total size that can be specified explicitly by
 475 // command line specification of OldSize and NewSize and
 476 // also a command line specification of -Xms.  Issue a warning
 477 // but allow the values to pass.
 478 
 479 void TwoGenerationCollectorPolicy::initialize_size_info() {
 480   GenCollectorPolicy::initialize_size_info();
 481 
 482   // At this point the minimum, initial and maximum sizes
 483   // of the overall heap and of gen0 have been determined.
 484   // The maximum gen1 size can be determined from the maximum gen0
 485   // and maximum heap size since no explicit flags exits
 486   // for setting the gen1 maximum.
 487   _max_gen1_size = max_heap_byte_size() - _max_gen0_size;
 488   _max_gen1_size =
 489     MAX2((uintx)align_size_down(_max_gen1_size, min_alignment()),
 490          min_alignment());
 491   // If no explicit command line flag has been set for the
 492   // gen1 size, use what is left for gen1.
 493   if (FLAG_IS_DEFAULT(OldSize) || FLAG_IS_ERGO(OldSize)) {
 494     // The user has not specified any value or ergonomics
 495     // has chosen a value (which may or may not be consistent
 496     // with the overall heap size).  In either case make
 497     // the minimum, maximum and initial sizes consistent
 498     // with the gen0 sizes and the overall heap sizes.
 499     assert(min_heap_byte_size() > _min_gen0_size,
 500       "gen0 has an unexpected minimum size");
 501     set_min_gen1_size(min_heap_byte_size() - min_gen0_size());
 502     set_min_gen1_size(
 503       MAX2((uintx)align_size_down(_min_gen1_size, min_alignment()),
 504            min_alignment()));
 505     set_initial_gen1_size(initial_heap_byte_size() - initial_gen0_size());
 506     set_initial_gen1_size(
 507       MAX2((uintx)align_size_down(_initial_gen1_size, min_alignment()),
 508            min_alignment()));
 509 
 510   } else {
 511     // It's been explicitly set on the command line.  Use the
 512     // OldSize and then determine the consequences.
 513     set_min_gen1_size(OldSize);
 514     set_initial_gen1_size(OldSize);
 515 
 516     // If the user has explicitly set an OldSize that is inconsistent
 517     // with other command line flags, issue a warning.
 518     // The generation minimums and the overall heap mimimum should
 519     // be within one heap alignment.
 520     if ((_min_gen1_size + _min_gen0_size + min_alignment()) <
 521            min_heap_byte_size()) {
 522       warning("Inconsistency between minimum heap size and minimum "
 523           "generation sizes: using minimum heap = " SIZE_FORMAT,
 524           min_heap_byte_size());
 525     }
 526     if ((OldSize > _max_gen1_size)) {
 527       warning("Inconsistency between maximum heap size and maximum "
 528           "generation sizes: using maximum heap = " SIZE_FORMAT
 529           " -XX:OldSize flag is being ignored",
 530           max_heap_byte_size());
 531     }
 532     // If there is an inconsistency between the OldSize and the minimum and/or
 533     // initial size of gen0, since OldSize was explicitly set, OldSize wins.
 534     if (adjust_gen0_sizes(&_min_gen0_size, &_min_gen1_size,
 535                           min_heap_byte_size(), OldSize)) {
 536       if (PrintGCDetails && Verbose) {
 537         gclog_or_tty->print_cr("2: Minimum gen0 " SIZE_FORMAT "  Initial gen0 "
 538               SIZE_FORMAT "  Maximum gen0 " SIZE_FORMAT,
 539               min_gen0_size(), initial_gen0_size(), max_gen0_size());
 540       }
 541     }
 542     // Initial size
 543     if (adjust_gen0_sizes(&_initial_gen0_size, &_initial_gen1_size,
 544                          initial_heap_byte_size(), OldSize)) {
 545       if (PrintGCDetails && Verbose) {
 546         gclog_or_tty->print_cr("3: Minimum gen0 " SIZE_FORMAT "  Initial gen0 "
 547           SIZE_FORMAT "  Maximum gen0 " SIZE_FORMAT,
 548           min_gen0_size(), initial_gen0_size(), max_gen0_size());
 549       }
 550     }
 551   }
 552   // Enforce the maximum gen1 size.
 553   set_min_gen1_size(MIN2(_min_gen1_size, _max_gen1_size));
 554 
 555   // Check that min gen1 <= initial gen1 <= max gen1
 556   set_initial_gen1_size(MAX2(_initial_gen1_size, _min_gen1_size));
 557   set_initial_gen1_size(MIN2(_initial_gen1_size, _max_gen1_size));
 558 
 559   if (PrintGCDetails && Verbose) {
 560     gclog_or_tty->print_cr("Minimum gen1 " SIZE_FORMAT "  Initial gen1 "
 561       SIZE_FORMAT "  Maximum gen1 " SIZE_FORMAT,
 562       min_gen1_size(), initial_gen1_size(), max_gen1_size());
 563   }
 564 }
 565 
 566 HeapWord* GenCollectorPolicy::mem_allocate_work(size_t size,
 567                                         bool is_tlab,
 568                                         bool* gc_overhead_limit_was_exceeded) {
 569   GenCollectedHeap *gch = GenCollectedHeap::heap();
 570 
 571   debug_only(gch->check_for_valid_allocation_state());
 572   assert(gch->no_gc_in_progress(), "Allocation during gc not allowed");
 573 
 574   // In general gc_overhead_limit_was_exceeded should be false so
 575   // set it so here and reset it to true only if the gc time
 576   // limit is being exceeded as checked below.
 577   *gc_overhead_limit_was_exceeded = false;
 578 
 579   HeapWord* result = NULL;
 580 
 581   // Loop until the allocation is satisified,
 582   // or unsatisfied after GC.
 583   for (int try_count = 1, gclocker_stalled_count = 0; /* return or throw */; try_count += 1) {
 584     HandleMark hm; // discard any handles allocated in each iteration
 585 
 586     // First allocation attempt is lock-free.
 587     Generation *gen0 = gch->get_gen(0);
 588     assert(gen0->supports_inline_contig_alloc(),
 589       "Otherwise, must do alloc within heap lock");
 590     if (gen0->should_allocate(size, is_tlab)) {
 591       result = gen0->par_allocate(size, is_tlab);
 592       if (result != NULL) {
 593         assert(gch->is_in_reserved(result), "result not in heap");
 594         return result;
 595       }
 596     }
 597     unsigned int gc_count_before;  // read inside the Heap_lock locked region
 598     {
 599       MutexLocker ml(Heap_lock);
 600       if (PrintGC && Verbose) {
 601         gclog_or_tty->print_cr("TwoGenerationCollectorPolicy::mem_allocate_work:"
 602                       " attempting locked slow path allocation");
 603       }
 604       // Note that only large objects get a shot at being
 605       // allocated in later generations.
 606       bool first_only = ! should_try_older_generation_allocation(size);
 607 
 608       result = gch->attempt_allocation(size, is_tlab, first_only);
 609       if (result != NULL) {
 610         assert(gch->is_in_reserved(result), "result not in heap");
 611         return result;
 612       }
 613 
 614       if (GC_locker::is_active_and_needs_gc()) {
 615         if (is_tlab) {
 616           return NULL;  // Caller will retry allocating individual object
 617         }
 618         if (!gch->is_maximal_no_gc()) {
 619           // Try and expand heap to satisfy request
 620           result = expand_heap_and_allocate(size, is_tlab);
 621           // result could be null if we are out of space
 622           if (result != NULL) {
 623             return result;
 624           }
 625         }
 626 
 627         if (gclocker_stalled_count > GCLockerRetryAllocationCount) {
 628           return NULL; // we didn't get to do a GC and we didn't get any memory
 629         }
 630 
 631         // If this thread is not in a jni critical section, we stall
 632         // the requestor until the critical section has cleared and
 633         // GC allowed. When the critical section clears, a GC is
 634         // initiated by the last thread exiting the critical section; so
 635         // we retry the allocation sequence from the beginning of the loop,
 636         // rather than causing more, now probably unnecessary, GC attempts.
 637         JavaThread* jthr = JavaThread::current();
 638         if (!jthr->in_critical()) {
 639           MutexUnlocker mul(Heap_lock);
 640           // Wait for JNI critical section to be exited
 641           GC_locker::stall_until_clear();
 642           gclocker_stalled_count += 1;
 643           continue;
 644         } else {
 645           if (CheckJNICalls) {
 646             fatal("Possible deadlock due to allocating while"
 647                   " in jni critical section");
 648           }
 649           return NULL;
 650         }
 651       }
 652 
 653       // Read the gc count while the heap lock is held.
 654       gc_count_before = Universe::heap()->total_collections();
 655     }
 656 
 657     VM_GenCollectForAllocation op(size,
 658                                   is_tlab,
 659                                   gc_count_before);
 660     VMThread::execute(&op);
 661     if (op.prologue_succeeded()) {
 662       result = op.result();
 663       if (op.gc_locked()) {
 664          assert(result == NULL, "must be NULL if gc_locked() is true");
 665          continue;  // retry and/or stall as necessary
 666       }
 667 
 668       // Allocation has failed and a collection
 669       // has been done.  If the gc time limit was exceeded the
 670       // this time, return NULL so that an out-of-memory
 671       // will be thrown.  Clear gc_overhead_limit_exceeded
 672       // so that the overhead exceeded does not persist.
 673 
 674       const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded();
 675       const bool softrefs_clear = all_soft_refs_clear();
 676 
 677       if (limit_exceeded && softrefs_clear) {
 678         *gc_overhead_limit_was_exceeded = true;
 679         size_policy()->set_gc_overhead_limit_exceeded(false);
 680         if (op.result() != NULL) {
 681           CollectedHeap::fill_with_object(op.result(), size);
 682         }
 683         return NULL;
 684       }
 685       assert(result == NULL || gch->is_in_reserved(result),
 686              "result not in heap");
 687       return result;
 688     }
 689 
 690     // Give a warning if we seem to be looping forever.
 691     if ((QueuedAllocationWarningCount > 0) &&
 692         (try_count % QueuedAllocationWarningCount == 0)) {
 693           warning("TwoGenerationCollectorPolicy::mem_allocate_work retries %d times \n\t"
 694                   " size=%d %s", try_count, size, is_tlab ? "(TLAB)" : "");
 695     }
 696   }
 697 }
 698 
 699 HeapWord* GenCollectorPolicy::expand_heap_and_allocate(size_t size,
 700                                                        bool   is_tlab) {
 701   GenCollectedHeap *gch = GenCollectedHeap::heap();
 702   HeapWord* result = NULL;
 703   for (int i = number_of_generations() - 1; i >= 0 && result == NULL; i--) {
 704     Generation *gen = gch->get_gen(i);
 705     if (gen->should_allocate(size, is_tlab)) {
 706       result = gen->expand_and_allocate(size, is_tlab);
 707     }
 708   }
 709   assert(result == NULL || gch->is_in_reserved(result), "result not in heap");
 710   return result;
 711 }
 712 
 713 HeapWord* GenCollectorPolicy::satisfy_failed_allocation(size_t size,
 714                                                         bool   is_tlab) {
 715   GenCollectedHeap *gch = GenCollectedHeap::heap();
 716   GCCauseSetter x(gch, GCCause::_allocation_failure);
 717   HeapWord* result = NULL;
 718 
 719   assert(size != 0, "Precondition violated");
 720   if (GC_locker::is_active_and_needs_gc()) {
 721     // GC locker is active; instead of a collection we will attempt
 722     // to expand the heap, if there's room for expansion.
 723     if (!gch->is_maximal_no_gc()) {
 724       result = expand_heap_and_allocate(size, is_tlab);
 725     }
 726     return result;   // could be null if we are out of space
 727   } else if (!gch->incremental_collection_will_fail(false /* don't consult_young */)) {
 728     // Do an incremental collection.
 729     gch->do_collection(false            /* full */,
 730                        false            /* clear_all_soft_refs */,
 731                        size             /* size */,
 732                        is_tlab          /* is_tlab */,
 733                        number_of_generations() - 1 /* max_level */);
 734   } else {
 735     if (Verbose && PrintGCDetails) {
 736       gclog_or_tty->print(" :: Trying full because partial may fail :: ");
 737     }
 738     // Try a full collection; see delta for bug id 6266275
 739     // for the original code and why this has been simplified
 740     // with from-space allocation criteria modified and
 741     // such allocation moved out of the safepoint path.
 742     gch->do_collection(true             /* full */,
 743                        false            /* clear_all_soft_refs */,
 744                        size             /* size */,
 745                        is_tlab          /* is_tlab */,
 746                        number_of_generations() - 1 /* max_level */);
 747   }
 748 
 749   result = gch->attempt_allocation(size, is_tlab, false /*first_only*/);
 750 
 751   if (result != NULL) {
 752     assert(gch->is_in_reserved(result), "result not in heap");
 753     return result;
 754   }
 755 
 756   // OK, collection failed, try expansion.
 757   result = expand_heap_and_allocate(size, is_tlab);
 758   if (result != NULL) {
 759     return result;
 760   }
 761 
 762   // If we reach this point, we're really out of memory. Try every trick
 763   // we can to reclaim memory. Force collection of soft references. Force
 764   // a complete compaction of the heap. Any additional methods for finding
 765   // free memory should be here, especially if they are expensive. If this
 766   // attempt fails, an OOM exception will be thrown.
 767   {
 768     UIntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted
 769 
 770     gch->do_collection(true             /* full */,
 771                        true             /* clear_all_soft_refs */,
 772                        size             /* size */,
 773                        is_tlab          /* is_tlab */,
 774                        number_of_generations() - 1 /* max_level */);
 775   }
 776 
 777   result = gch->attempt_allocation(size, is_tlab, false /* first_only */);
 778   if (result != NULL) {
 779     assert(gch->is_in_reserved(result), "result not in heap");
 780     return result;
 781   }
 782 
 783   assert(!should_clear_all_soft_refs(),
 784     "Flag should have been handled and cleared prior to this point");
 785 
 786   // What else?  We might try synchronous finalization later.  If the total
 787   // space available is large enough for the allocation, then a more
 788   // complete compaction phase than we've tried so far might be
 789   // appropriate.
 790   return NULL;
 791 }
 792 
 793 MetaWord* CollectorPolicy::satisfy_failed_metadata_allocation(
 794                                                  ClassLoaderData* loader_data,
 795                                                  size_t word_size,
 796                                                  Metaspace::MetadataType mdtype) {
 797   uint loop_count = 0;
 798   uint gc_count = 0;
 799   uint full_gc_count = 0;
 800 
 801   assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");
 802 
 803   do {
 804     MetaWord* result = NULL;
 805     if (GC_locker::is_active_and_needs_gc()) {
 806       // If the GC_locker is active, just expand and allocate.
 807       // If that does not succeed, wait if this thread is not
 808       // in a critical section itself.
 809       result =
 810         loader_data->metaspace_non_null()->expand_and_allocate(word_size,
 811                                                                mdtype);
 812       if (result != NULL) {
 813         return result;
 814       }
 815       JavaThread* jthr = JavaThread::current();
 816       if (!jthr->in_critical()) {
 817         // Wait for JNI critical section to be exited
 818         GC_locker::stall_until_clear();
 819         // The GC invoked by the last thread leaving the critical
 820         // section will be a young collection and a full collection
 821         // is (currently) needed for unloading classes so continue
 822         // to the next iteration to get a full GC.
 823         continue;
 824       } else {
 825         if (CheckJNICalls) {
 826           fatal("Possible deadlock due to allocating while"
 827                 " in jni critical section");
 828         }
 829         return NULL;
 830       }
 831     }
 832 
 833     {  // Need lock to get self consistent gc_count's
 834       MutexLocker ml(Heap_lock);
 835       gc_count      = Universe::heap()->total_collections();
 836       full_gc_count = Universe::heap()->total_full_collections();
 837     }
 838 
 839     // Generate a VM operation
 840     VM_CollectForMetadataAllocation op(loader_data,
 841                                        word_size,
 842                                        mdtype,
 843                                        gc_count,
 844                                        full_gc_count,
 845                                        GCCause::_metadata_GC_threshold);
 846     VMThread::execute(&op);
 847 
 848     // If GC was locked out, try again.  Check
 849     // before checking success because the prologue
 850     // could have succeeded and the GC still have
 851     // been locked out.
 852     if (op.gc_locked()) {
 853       continue;
 854     }
 855 
 856     if (op.prologue_succeeded()) {
 857       return op.result();
 858     }
 859     loop_count++;
 860     if ((QueuedAllocationWarningCount > 0) &&
 861         (loop_count % QueuedAllocationWarningCount == 0)) {
 862       warning("satisfy_failed_metadata_allocation() retries %d times \n\t"
 863               " size=%d", loop_count, word_size);
 864     }
 865   } while (true);  // Until a GC is done
 866 }
 867 
 868 // Return true if any of the following is true:
 869 // . the allocation won't fit into the current young gen heap
 870 // . gc locker is occupied (jni critical section)
 871 // . heap memory is tight -- the most recent previous collection
 872 //   was a full collection because a partial collection (would
 873 //   have) failed and is likely to fail again
 874 bool GenCollectorPolicy::should_try_older_generation_allocation(
 875         size_t word_size) const {
 876   GenCollectedHeap* gch = GenCollectedHeap::heap();
 877   size_t gen0_capacity = gch->get_gen(0)->capacity_before_gc();
 878   return    (word_size > heap_word_size(gen0_capacity))
 879          || GC_locker::is_active_and_needs_gc()
 880          || gch->incremental_collection_failed();
 881 }
 882 
 883 
 884 //
 885 // MarkSweepPolicy methods
 886 //
 887 
 888 MarkSweepPolicy::MarkSweepPolicy() {
 889   initialize_all();
 890 }
 891 
 892 void MarkSweepPolicy::initialize_generations() {
 893   _generations = NEW_C_HEAP_ARRAY3(GenerationSpecPtr, number_of_generations(), mtGC, 0, AllocFailStrategy::RETURN_NULL);
 894   if (_generations == NULL)
 895     vm_exit_during_initialization("Unable to allocate gen spec");
 896 
 897   if (UseParNewGC) {
 898     _generations[0] = new GenerationSpec(Generation::ParNew, _initial_gen0_size, _max_gen0_size);
 899   } else {
 900     _generations[0] = new GenerationSpec(Generation::DefNew, _initial_gen0_size, _max_gen0_size);
 901   }
 902   _generations[1] = new GenerationSpec(Generation::MarkSweepCompact, _initial_gen1_size, _max_gen1_size);
 903 
 904   if (_generations[0] == NULL || _generations[1] == NULL)
 905     vm_exit_during_initialization("Unable to allocate gen spec");
 906 }
 907 
 908 void MarkSweepPolicy::initialize_gc_policy_counters() {
 909   // initialize the policy counters - 2 collectors, 3 generations
 910   if (UseParNewGC) {
 911     _gc_policy_counters = new GCPolicyCounters("ParNew:MSC", 2, 3);
 912   } else {
 913     _gc_policy_counters = new GCPolicyCounters("Copy:MSC", 2, 3);
 914   }
 915 }
--- EOF ---