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     FLAG_SET_ERGO(uintx, MaxMetaspaceSize,
  69         restricted_align_down(MaxMetaspaceSize, max_alignment()));
  70   }
  71 
  72   if (MetaspaceSize > MaxMetaspaceSize) {
  73     FLAG_SET_ERGO(uintx, MetaspaceSize, MaxMetaspaceSize);
  74   }
  75 
  76   if (!is_size_aligned(MetaspaceSize, min_alignment())) {
  77     FLAG_SET_ERGO(uintx, MetaspaceSize,
  78         restricted_align_down(MetaspaceSize, min_alignment()));
  79   }
  80 
  81   assert(MetaspaceSize <= MaxMetaspaceSize, "Must be");
  82 
  83   MinMetaspaceExpansion = restricted_align_down(MinMetaspaceExpansion, min_alignment());
  84   MaxMetaspaceExpansion = restricted_align_down(MaxMetaspaceExpansion, min_alignment());
  85 
  86   MinHeapDeltaBytes = align_size_up(MinHeapDeltaBytes, min_alignment());
  87 
  88   assert(MetaspaceSize    % min_alignment() == 0, "metapace alignment");
  89   assert(MaxMetaspaceSize % max_alignment() == 0, "maximum metaspace alignment");
  90   if (MetaspaceSize < 256*K) {
  91     vm_exit_during_initialization("Too small initial Metaspace size");
  92   }
  93 }
  94 
  95 void CollectorPolicy::initialize_size_info() {
  96   // User inputs from -mx and ms must be aligned
  97   set_min_heap_byte_size(align_size_up(Arguments::min_heap_size(), min_alignment()));
  98   set_initial_heap_byte_size(align_size_up(InitialHeapSize, min_alignment()));
  99   set_max_heap_byte_size(align_size_up(MaxHeapSize, max_alignment()));
 100 
 101   // Check heap parameter properties
 102   if (initial_heap_byte_size() < M) {
 103     vm_exit_during_initialization("Too small initial heap");
 104   }
 105   // Check heap parameter properties
 106   if (min_heap_byte_size() < M) {
 107     vm_exit_during_initialization("Too small minimum heap");
 108   }
 109   if (initial_heap_byte_size() <= NewSize) {
 110      // make sure there is at least some room in old space
 111     vm_exit_during_initialization("Too small initial heap for new size specified");
 112   }
 113   if (max_heap_byte_size() < min_heap_byte_size()) {
 114     vm_exit_during_initialization("Incompatible minimum and maximum heap sizes specified");
 115   }
 116   if (initial_heap_byte_size() < min_heap_byte_size()) {
 117     vm_exit_during_initialization("Incompatible minimum and initial heap sizes specified");
 118   }
 119   if (max_heap_byte_size() < initial_heap_byte_size()) {
 120     vm_exit_during_initialization("Incompatible initial and maximum heap sizes specified");
 121   }
 122 
 123   if (PrintGCDetails && Verbose) {
 124     gclog_or_tty->print_cr("Minimum heap " SIZE_FORMAT "  Initial heap "
 125       SIZE_FORMAT "  Maximum heap " SIZE_FORMAT,
 126       min_heap_byte_size(), initial_heap_byte_size(), max_heap_byte_size());
 127   }
 128 }
 129 
 130 bool CollectorPolicy::use_should_clear_all_soft_refs(bool v) {
 131   bool result = _should_clear_all_soft_refs;
 132   set_should_clear_all_soft_refs(false);
 133   return result;
 134 }
 135 
 136 GenRemSet* CollectorPolicy::create_rem_set(MemRegion whole_heap,
 137                                            int max_covered_regions) {
 138   switch (rem_set_name()) {
 139   case GenRemSet::CardTable: {
 140     CardTableRS* res = new CardTableRS(whole_heap, max_covered_regions);
 141     return res;
 142   }
 143   default:
 144     guarantee(false, "unrecognized GenRemSet::Name");
 145     return NULL;
 146   }
 147 }
 148 
 149 void CollectorPolicy::cleared_all_soft_refs() {
 150   // If near gc overhear limit, continue to clear SoftRefs.  SoftRefs may
 151   // have been cleared in the last collection but if the gc overhear
 152   // limit continues to be near, SoftRefs should still be cleared.
 153   if (size_policy() != NULL) {
 154     _should_clear_all_soft_refs = size_policy()->gc_overhead_limit_near();
 155   }
 156   _all_soft_refs_clear = true;
 157 }
 158 
 159 size_t CollectorPolicy::compute_max_alignment() {
 160   // The card marking array and the offset arrays for old generations are
 161   // committed in os pages as well. Make sure they are entirely full (to
 162   // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1
 163   // byte entry and the os page size is 4096, the maximum heap size should
 164   // be 512*4096 = 2MB aligned.
 165 
 166   // There is only the GenRemSet in Hotspot and only the GenRemSet::CardTable
 167   // is supported.
 168   // Requirements of any new remembered set implementations must be added here.
 169   size_t alignment = GenRemSet::max_alignment_constraint(GenRemSet::CardTable);
 170 
 171   // Parallel GC does its own alignment of the generations to avoid requiring a
 172   // large page (256M on some platforms) for the permanent generation.  The
 173   // other collectors should also be updated to do their own alignment and then
 174   // this use of lcm() should be removed.
 175   if (UseLargePages && !UseParallelGC) {
 176       // in presence of large pages we have to make sure that our
 177       // alignment is large page aware
 178       alignment = lcm(os::large_page_size(), alignment);
 179   }
 180 
 181   return alignment;
 182 }
 183 
 184 // GenCollectorPolicy methods.
 185 
 186 size_t GenCollectorPolicy::scale_by_NewRatio_aligned(size_t base_size) {
 187   size_t x = base_size / (NewRatio+1);
 188   size_t new_gen_size = x > min_alignment() ?
 189                      align_size_down(x, min_alignment()) :
 190                      min_alignment();
 191   return new_gen_size;
 192 }
 193 
 194 size_t GenCollectorPolicy::bound_minus_alignment(size_t desired_size,
 195                                                  size_t maximum_size) {
 196   size_t alignment = min_alignment();
 197   size_t max_minus = maximum_size - alignment;
 198   return desired_size < max_minus ? desired_size : max_minus;
 199 }
 200 
 201 
 202 void GenCollectorPolicy::initialize_size_policy(size_t init_eden_size,
 203                                                 size_t init_promo_size,
 204                                                 size_t init_survivor_size) {
 205   const double max_gc_pause_sec = ((double) MaxGCPauseMillis)/1000.0;
 206   _size_policy = new AdaptiveSizePolicy(init_eden_size,
 207                                         init_promo_size,
 208                                         init_survivor_size,
 209                                         max_gc_pause_sec,
 210                                         GCTimeRatio);
 211 }
 212 
 213 void GenCollectorPolicy::initialize_flags() {
 214   // All sizes must be multiples of the generation granularity.
 215   set_min_alignment((uintx) Generation::GenGrain);
 216   set_max_alignment(compute_max_alignment());
 217 
 218   CollectorPolicy::initialize_flags();
 219 
 220   // All generational heaps have a youngest gen; handle those flags here.
 221 
 222   // Adjust max size parameters
 223   if (NewSize > MaxNewSize) {
 224     MaxNewSize = NewSize;
 225   }
 226   NewSize = align_size_down(NewSize, min_alignment());
 227   MaxNewSize = align_size_down(MaxNewSize, min_alignment());
 228 
 229   // Check validity of heap flags
 230   assert(NewSize     % min_alignment() == 0, "eden space alignment");
 231   assert(MaxNewSize  % min_alignment() == 0, "survivor space alignment");
 232 
 233   if (NewSize < 3*min_alignment()) {
 234      // make sure there room for eden and two survivor spaces
 235     vm_exit_during_initialization("Too small new size specified");
 236   }
 237   if (SurvivorRatio < 1 || NewRatio < 1) {
 238     vm_exit_during_initialization("Invalid heap ratio specified");
 239   }
 240 }
 241 
 242 void TwoGenerationCollectorPolicy::initialize_flags() {
 243   GenCollectorPolicy::initialize_flags();
 244 
 245   OldSize = align_size_down(OldSize, min_alignment());
 246 
 247   if (FLAG_IS_CMDLINE(OldSize) && FLAG_IS_DEFAULT(NewSize)) {
 248     // NewRatio will be used later to set the young generation size so we use
 249     // it to calculate how big the heap should be based on the requested OldSize
 250     // and NewRatio.
 251     assert(NewRatio > 0, "NewRatio should have been set up earlier");
 252     size_t calculated_heapsize = (OldSize / NewRatio) * (NewRatio + 1);
 253 
 254     calculated_heapsize = align_size_up(calculated_heapsize, max_alignment());
 255     MaxHeapSize = calculated_heapsize;
 256     InitialHeapSize = calculated_heapsize;
 257   }
 258   MaxHeapSize = align_size_up(MaxHeapSize, max_alignment());
 259 
 260   // adjust max heap size if necessary
 261   if (NewSize + OldSize > MaxHeapSize) {
 262     if (FLAG_IS_CMDLINE(MaxHeapSize)) {
 263       // somebody set a maximum heap size with the intention that we should not
 264       // exceed it. Adjust New/OldSize as necessary.
 265       uintx calculated_size = NewSize + OldSize;
 266       double shrink_factor = (double) MaxHeapSize / calculated_size;
 267       // align
 268       NewSize = align_size_down((uintx) (NewSize * shrink_factor), min_alignment());
 269       // OldSize is already aligned because above we aligned MaxHeapSize to
 270       // max_alignment(), and we just made sure that NewSize is aligned to
 271       // min_alignment(). In initialize_flags() we verified that max_alignment()
 272       // is a multiple of min_alignment().
 273       OldSize = MaxHeapSize - NewSize;
 274     } else {
 275       MaxHeapSize = NewSize + OldSize;
 276     }
 277   }
 278   // need to do this again
 279   MaxHeapSize = align_size_up(MaxHeapSize, max_alignment());
 280 
 281   // adjust max heap size if necessary
 282   if (NewSize + OldSize > MaxHeapSize) {
 283     if (FLAG_IS_CMDLINE(MaxHeapSize)) {
 284       // somebody set a maximum heap size with the intention that we should not
 285       // exceed it. Adjust New/OldSize as necessary.
 286       uintx calculated_size = NewSize + OldSize;
 287       double shrink_factor = (double) MaxHeapSize / calculated_size;
 288       // align
 289       NewSize = align_size_down((uintx) (NewSize * shrink_factor), min_alignment());
 290       // OldSize is already aligned because above we aligned MaxHeapSize to
 291       // max_alignment(), and we just made sure that NewSize is aligned to
 292       // min_alignment(). In initialize_flags() we verified that max_alignment()
 293       // is a multiple of min_alignment().
 294       OldSize = MaxHeapSize - NewSize;
 295     } else {
 296       MaxHeapSize = NewSize + OldSize;
 297     }
 298   }
 299   // need to do this again
 300   MaxHeapSize = align_size_up(MaxHeapSize, max_alignment());
 301 
 302   always_do_update_barrier = UseConcMarkSweepGC;
 303 
 304   // Check validity of heap flags
 305   assert(OldSize     % min_alignment() == 0, "old space alignment");
 306   assert(MaxHeapSize % max_alignment() == 0, "maximum heap alignment");
 307 }
 308 
 309 // Values set on the command line win over any ergonomically
 310 // set command line parameters.
 311 // Ergonomic choice of parameters are done before this
 312 // method is called.  Values for command line parameters such as NewSize
 313 // and MaxNewSize feed those ergonomic choices into this method.
 314 // This method makes the final generation sizings consistent with
 315 // themselves and with overall heap sizings.
 316 // In the absence of explicitly set command line flags, policies
 317 // such as the use of NewRatio are used to size the generation.
 318 void GenCollectorPolicy::initialize_size_info() {
 319   CollectorPolicy::initialize_size_info();
 320 
 321   // min_alignment() is used for alignment within a generation.
 322   // There is additional alignment done down stream for some
 323   // collectors that sometimes causes unwanted rounding up of
 324   // generations sizes.
 325 
 326   // Determine maximum size of gen0
 327 
 328   size_t max_new_size = 0;
 329   if (FLAG_IS_CMDLINE(MaxNewSize) || FLAG_IS_ERGO(MaxNewSize)) {
 330     if (MaxNewSize < min_alignment()) {
 331       max_new_size = min_alignment();
 332     }
 333     if (MaxNewSize >= max_heap_byte_size()) {
 334       max_new_size = align_size_down(max_heap_byte_size() - min_alignment(),
 335                                      min_alignment());
 336       warning("MaxNewSize (" SIZE_FORMAT "k) is equal to or "
 337         "greater than the entire heap (" SIZE_FORMAT "k).  A "
 338         "new generation size of " SIZE_FORMAT "k will be used.",
 339         MaxNewSize/K, max_heap_byte_size()/K, max_new_size/K);
 340     } else {
 341       max_new_size = align_size_down(MaxNewSize, min_alignment());
 342     }
 343 
 344   // The case for FLAG_IS_ERGO(MaxNewSize) could be treated
 345   // specially at this point to just use an ergonomically set
 346   // MaxNewSize to set max_new_size.  For cases with small
 347   // heaps such a policy often did not work because the MaxNewSize
 348   // was larger than the entire heap.  The interpretation given
 349   // to ergonomically set flags is that the flags are set
 350   // by different collectors for their own special needs but
 351   // are not allowed to badly shape the heap.  This allows the
 352   // different collectors to decide what's best for themselves
 353   // without having to factor in the overall heap shape.  It
 354   // can be the case in the future that the collectors would
 355   // only make "wise" ergonomics choices and this policy could
 356   // just accept those choices.  The choices currently made are
 357   // not always "wise".
 358   } else {
 359     max_new_size = scale_by_NewRatio_aligned(max_heap_byte_size());
 360     // Bound the maximum size by NewSize below (since it historically
 361     // would have been NewSize and because the NewRatio calculation could
 362     // yield a size that is too small) and bound it by MaxNewSize above.
 363     // Ergonomics plays here by previously calculating the desired
 364     // NewSize and MaxNewSize.
 365     max_new_size = MIN2(MAX2(max_new_size, NewSize), MaxNewSize);
 366   }
 367   assert(max_new_size > 0, "All paths should set max_new_size");
 368 
 369   // Given the maximum gen0 size, determine the initial and
 370   // minimum gen0 sizes.
 371 
 372   if (max_heap_byte_size() == min_heap_byte_size()) {
 373     // The maximum and minimum heap sizes are the same so
 374     // the generations minimum and initial must be the
 375     // same as its maximum.
 376     set_min_gen0_size(max_new_size);
 377     set_initial_gen0_size(max_new_size);
 378     set_max_gen0_size(max_new_size);
 379   } else {
 380     size_t desired_new_size = 0;
 381     if (!FLAG_IS_DEFAULT(NewSize)) {
 382       // If NewSize is set ergonomically (for example by cms), it
 383       // would make sense to use it.  If it is used, also use it
 384       // to set the initial size.  Although there is no reason
 385       // the minimum size and the initial size have to be the same,
 386       // the current implementation gets into trouble during the calculation
 387       // of the tenured generation sizes if they are different.
 388       // Note that this makes the initial size and the minimum size
 389       // generally small compared to the NewRatio calculation.
 390       _min_gen0_size = NewSize;
 391       desired_new_size = NewSize;
 392       max_new_size = MAX2(max_new_size, NewSize);
 393     } else {
 394       // For the case where NewSize is the default, use NewRatio
 395       // to size the minimum and initial generation sizes.
 396       // Use the default NewSize as the floor for these values.  If
 397       // NewRatio is overly large, the resulting sizes can be too
 398       // small.
 399       _min_gen0_size = MAX2(scale_by_NewRatio_aligned(min_heap_byte_size()),
 400                           NewSize);
 401       desired_new_size =
 402         MAX2(scale_by_NewRatio_aligned(initial_heap_byte_size()),
 403              NewSize);
 404     }
 405 
 406     assert(_min_gen0_size > 0, "Sanity check");
 407     set_initial_gen0_size(desired_new_size);
 408     set_max_gen0_size(max_new_size);
 409 
 410     // At this point the desirable initial and minimum sizes have been
 411     // determined without regard to the maximum sizes.
 412 
 413     // Bound the sizes by the corresponding overall heap sizes.
 414     set_min_gen0_size(
 415       bound_minus_alignment(_min_gen0_size, min_heap_byte_size()));
 416     set_initial_gen0_size(
 417       bound_minus_alignment(_initial_gen0_size, initial_heap_byte_size()));
 418     set_max_gen0_size(
 419       bound_minus_alignment(_max_gen0_size, max_heap_byte_size()));
 420 
 421     // At this point all three sizes have been checked against the
 422     // maximum sizes but have not been checked for consistency
 423     // among the three.
 424 
 425     // Final check min <= initial <= max
 426     set_min_gen0_size(MIN2(_min_gen0_size, _max_gen0_size));
 427     set_initial_gen0_size(
 428       MAX2(MIN2(_initial_gen0_size, _max_gen0_size), _min_gen0_size));
 429     set_min_gen0_size(MIN2(_min_gen0_size, _initial_gen0_size));
 430   }
 431 
 432   if (PrintGCDetails && Verbose) {
 433     gclog_or_tty->print_cr("1: Minimum gen0 " SIZE_FORMAT "  Initial gen0 "
 434       SIZE_FORMAT "  Maximum gen0 " SIZE_FORMAT,
 435       min_gen0_size(), initial_gen0_size(), max_gen0_size());
 436   }
 437 }
 438 
 439 // Call this method during the sizing of the gen1 to make
 440 // adjustments to gen0 because of gen1 sizing policy.  gen0 initially has
 441 // the most freedom in sizing because it is done before the
 442 // policy for gen1 is applied.  Once gen1 policies have been applied,
 443 // there may be conflicts in the shape of the heap and this method
 444 // is used to make the needed adjustments.  The application of the
 445 // policies could be more sophisticated (iterative for example) but
 446 // keeping it simple also seems a worthwhile goal.
 447 bool TwoGenerationCollectorPolicy::adjust_gen0_sizes(size_t* gen0_size_ptr,
 448                                                      size_t* gen1_size_ptr,
 449                                                      const size_t heap_size,
 450                                                      const size_t min_gen1_size) {
 451   bool result = false;
 452 
 453   if ((*gen1_size_ptr + *gen0_size_ptr) > heap_size) {
 454     if ((heap_size < (*gen0_size_ptr + min_gen1_size)) &&
 455         (heap_size >= min_gen1_size + min_alignment())) {
 456       // Adjust gen0 down to accommodate min_gen1_size
 457       *gen0_size_ptr = heap_size - min_gen1_size;
 458       *gen0_size_ptr =
 459         MAX2((uintx)align_size_down(*gen0_size_ptr, min_alignment()),
 460              min_alignment());
 461       assert(*gen0_size_ptr > 0, "Min gen0 is too large");
 462       result = true;
 463     } else {
 464       *gen1_size_ptr = heap_size - *gen0_size_ptr;
 465       *gen1_size_ptr =
 466         MAX2((uintx)align_size_down(*gen1_size_ptr, min_alignment()),
 467                        min_alignment());
 468     }
 469   }
 470   return result;
 471 }
 472 
 473 // Minimum sizes of the generations may be different than
 474 // the initial sizes.  An inconsistently is permitted here
 475 // in the total size that can be specified explicitly by
 476 // command line specification of OldSize and NewSize and
 477 // also a command line specification of -Xms.  Issue a warning
 478 // but allow the values to pass.
 479 
 480 void TwoGenerationCollectorPolicy::initialize_size_info() {
 481   GenCollectorPolicy::initialize_size_info();
 482 
 483   // At this point the minimum, initial and maximum sizes
 484   // of the overall heap and of gen0 have been determined.
 485   // The maximum gen1 size can be determined from the maximum gen0
 486   // and maximum heap size since no explicit flags exits
 487   // for setting the gen1 maximum.
 488   _max_gen1_size = max_heap_byte_size() - _max_gen0_size;
 489   _max_gen1_size =
 490     MAX2((uintx)align_size_down(_max_gen1_size, min_alignment()),
 491          min_alignment());
 492   // If no explicit command line flag has been set for the
 493   // gen1 size, use what is left for gen1.
 494   if (FLAG_IS_DEFAULT(OldSize) || FLAG_IS_ERGO(OldSize)) {
 495     // The user has not specified any value or ergonomics
 496     // has chosen a value (which may or may not be consistent
 497     // with the overall heap size).  In either case make
 498     // the minimum, maximum and initial sizes consistent
 499     // with the gen0 sizes and the overall heap sizes.
 500     assert(min_heap_byte_size() > _min_gen0_size,
 501       "gen0 has an unexpected minimum size");
 502     set_min_gen1_size(min_heap_byte_size() - min_gen0_size());
 503     set_min_gen1_size(
 504       MAX2((uintx)align_size_down(_min_gen1_size, min_alignment()),
 505            min_alignment()));
 506     set_initial_gen1_size(initial_heap_byte_size() - initial_gen0_size());
 507     set_initial_gen1_size(
 508       MAX2((uintx)align_size_down(_initial_gen1_size, min_alignment()),
 509            min_alignment()));
 510 
 511   } else {
 512     // It's been explicitly set on the command line.  Use the
 513     // OldSize and then determine the consequences.
 514     set_min_gen1_size(OldSize);
 515     set_initial_gen1_size(OldSize);
 516 
 517     // If the user has explicitly set an OldSize that is inconsistent
 518     // with other command line flags, issue a warning.
 519     // The generation minimums and the overall heap mimimum should
 520     // be within one heap alignment.
 521     if ((_min_gen1_size + _min_gen0_size + min_alignment()) <
 522            min_heap_byte_size()) {
 523       warning("Inconsistency between minimum heap size and minimum "
 524           "generation sizes: using minimum heap = " SIZE_FORMAT,
 525           min_heap_byte_size());
 526     }
 527     if ((OldSize > _max_gen1_size)) {
 528       warning("Inconsistency between maximum heap size and maximum "
 529           "generation sizes: using maximum heap = " SIZE_FORMAT
 530           " -XX:OldSize flag is being ignored",
 531           max_heap_byte_size());
 532     }
 533     // If there is an inconsistency between the OldSize and the minimum and/or
 534     // initial size of gen0, since OldSize was explicitly set, OldSize wins.
 535     if (adjust_gen0_sizes(&_min_gen0_size, &_min_gen1_size,
 536                           min_heap_byte_size(), OldSize)) {
 537       if (PrintGCDetails && Verbose) {
 538         gclog_or_tty->print_cr("2: Minimum gen0 " SIZE_FORMAT "  Initial gen0 "
 539               SIZE_FORMAT "  Maximum gen0 " SIZE_FORMAT,
 540               min_gen0_size(), initial_gen0_size(), max_gen0_size());
 541       }
 542     }
 543     // Initial size
 544     if (adjust_gen0_sizes(&_initial_gen0_size, &_initial_gen1_size,
 545                          initial_heap_byte_size(), OldSize)) {
 546       if (PrintGCDetails && Verbose) {
 547         gclog_or_tty->print_cr("3: Minimum gen0 " SIZE_FORMAT "  Initial gen0 "
 548           SIZE_FORMAT "  Maximum gen0 " SIZE_FORMAT,
 549           min_gen0_size(), initial_gen0_size(), max_gen0_size());
 550       }
 551     }
 552   }
 553   // Enforce the maximum gen1 size.
 554   set_min_gen1_size(MIN2(_min_gen1_size, _max_gen1_size));
 555 
 556   // Check that min gen1 <= initial gen1 <= max gen1
 557   set_initial_gen1_size(MAX2(_initial_gen1_size, _min_gen1_size));
 558   set_initial_gen1_size(MIN2(_initial_gen1_size, _max_gen1_size));
 559 
 560   if (PrintGCDetails && Verbose) {
 561     gclog_or_tty->print_cr("Minimum gen1 " SIZE_FORMAT "  Initial gen1 "
 562       SIZE_FORMAT "  Maximum gen1 " SIZE_FORMAT,
 563       min_gen1_size(), initial_gen1_size(), max_gen1_size());
 564   }
 565 }
 566 
 567 HeapWord* GenCollectorPolicy::mem_allocate_work(size_t size,
 568                                         bool is_tlab,
 569                                         bool* gc_overhead_limit_was_exceeded) {
 570   GenCollectedHeap *gch = GenCollectedHeap::heap();
 571 
 572   debug_only(gch->check_for_valid_allocation_state());
 573   assert(gch->no_gc_in_progress(), "Allocation during gc not allowed");
 574 
 575   // In general gc_overhead_limit_was_exceeded should be false so
 576   // set it so here and reset it to true only if the gc time
 577   // limit is being exceeded as checked below.
 578   *gc_overhead_limit_was_exceeded = false;
 579 
 580   HeapWord* result = NULL;
 581 
 582   // Loop until the allocation is satisified,
 583   // or unsatisfied after GC.
 584   for (int try_count = 1, gclocker_stalled_count = 0; /* return or throw */; try_count += 1) {
 585     HandleMark hm; // discard any handles allocated in each iteration
 586 
 587     // First allocation attempt is lock-free.
 588     Generation *gen0 = gch->get_gen(0);
 589     assert(gen0->supports_inline_contig_alloc(),
 590       "Otherwise, must do alloc within heap lock");
 591     if (gen0->should_allocate(size, is_tlab)) {
 592       result = gen0->par_allocate(size, is_tlab);
 593       if (result != NULL) {
 594         assert(gch->is_in_reserved(result), "result not in heap");
 595         return result;
 596       }
 597     }
 598     unsigned int gc_count_before;  // read inside the Heap_lock locked region
 599     {
 600       MutexLocker ml(Heap_lock);
 601       if (PrintGC && Verbose) {
 602         gclog_or_tty->print_cr("TwoGenerationCollectorPolicy::mem_allocate_work:"
 603                       " attempting locked slow path allocation");
 604       }
 605       // Note that only large objects get a shot at being
 606       // allocated in later generations.
 607       bool first_only = ! should_try_older_generation_allocation(size);
 608 
 609       result = gch->attempt_allocation(size, is_tlab, first_only);
 610       if (result != NULL) {
 611         assert(gch->is_in_reserved(result), "result not in heap");
 612         return result;
 613       }
 614 
 615       if (GC_locker::is_active_and_needs_gc()) {
 616         if (is_tlab) {
 617           return NULL;  // Caller will retry allocating individual object
 618         }
 619         if (!gch->is_maximal_no_gc()) {
 620           // Try and expand heap to satisfy request
 621           result = expand_heap_and_allocate(size, is_tlab);
 622           // result could be null if we are out of space
 623           if (result != NULL) {
 624             return result;
 625           }
 626         }
 627 
 628         if (gclocker_stalled_count > GCLockerRetryAllocationCount) {
 629           return NULL; // we didn't get to do a GC and we didn't get any memory
 630         }
 631 
 632         // If this thread is not in a jni critical section, we stall
 633         // the requestor until the critical section has cleared and
 634         // GC allowed. When the critical section clears, a GC is
 635         // initiated by the last thread exiting the critical section; so
 636         // we retry the allocation sequence from the beginning of the loop,
 637         // rather than causing more, now probably unnecessary, GC attempts.
 638         JavaThread* jthr = JavaThread::current();
 639         if (!jthr->in_critical()) {
 640           MutexUnlocker mul(Heap_lock);
 641           // Wait for JNI critical section to be exited
 642           GC_locker::stall_until_clear();
 643           gclocker_stalled_count += 1;
 644           continue;
 645         } else {
 646           if (CheckJNICalls) {
 647             fatal("Possible deadlock due to allocating while"
 648                   " in jni critical section");
 649           }
 650           return NULL;
 651         }
 652       }
 653 
 654       // Read the gc count while the heap lock is held.
 655       gc_count_before = Universe::heap()->total_collections();
 656     }
 657 
 658     VM_GenCollectForAllocation op(size,
 659                                   is_tlab,
 660                                   gc_count_before);
 661     VMThread::execute(&op);
 662     if (op.prologue_succeeded()) {
 663       result = op.result();
 664       if (op.gc_locked()) {
 665          assert(result == NULL, "must be NULL if gc_locked() is true");
 666          continue;  // retry and/or stall as necessary
 667       }
 668 
 669       // Allocation has failed and a collection
 670       // has been done.  If the gc time limit was exceeded the
 671       // this time, return NULL so that an out-of-memory
 672       // will be thrown.  Clear gc_overhead_limit_exceeded
 673       // so that the overhead exceeded does not persist.
 674 
 675       const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded();
 676       const bool softrefs_clear = all_soft_refs_clear();
 677 
 678       if (limit_exceeded && softrefs_clear) {
 679         *gc_overhead_limit_was_exceeded = true;
 680         size_policy()->set_gc_overhead_limit_exceeded(false);
 681         if (op.result() != NULL) {
 682           CollectedHeap::fill_with_object(op.result(), size);
 683         }
 684         return NULL;
 685       }
 686       assert(result == NULL || gch->is_in_reserved(result),
 687              "result not in heap");
 688       return result;
 689     }
 690 
 691     // Give a warning if we seem to be looping forever.
 692     if ((QueuedAllocationWarningCount > 0) &&
 693         (try_count % QueuedAllocationWarningCount == 0)) {
 694           warning("TwoGenerationCollectorPolicy::mem_allocate_work retries %d times \n\t"
 695                   " size=%d %s", try_count, size, is_tlab ? "(TLAB)" : "");
 696     }
 697   }
 698 }
 699 
 700 HeapWord* GenCollectorPolicy::expand_heap_and_allocate(size_t size,
 701                                                        bool   is_tlab) {
 702   GenCollectedHeap *gch = GenCollectedHeap::heap();
 703   HeapWord* result = NULL;
 704   for (int i = number_of_generations() - 1; i >= 0 && result == NULL; i--) {
 705     Generation *gen = gch->get_gen(i);
 706     if (gen->should_allocate(size, is_tlab)) {
 707       result = gen->expand_and_allocate(size, is_tlab);
 708     }
 709   }
 710   assert(result == NULL || gch->is_in_reserved(result), "result not in heap");
 711   return result;
 712 }
 713 
 714 HeapWord* GenCollectorPolicy::satisfy_failed_allocation(size_t size,
 715                                                         bool   is_tlab) {
 716   GenCollectedHeap *gch = GenCollectedHeap::heap();
 717   GCCauseSetter x(gch, GCCause::_allocation_failure);
 718   HeapWord* result = NULL;
 719 
 720   assert(size != 0, "Precondition violated");
 721   if (GC_locker::is_active_and_needs_gc()) {
 722     // GC locker is active; instead of a collection we will attempt
 723     // to expand the heap, if there's room for expansion.
 724     if (!gch->is_maximal_no_gc()) {
 725       result = expand_heap_and_allocate(size, is_tlab);
 726     }
 727     return result;   // could be null if we are out of space
 728   } else if (!gch->incremental_collection_will_fail(false /* don't consult_young */)) {
 729     // Do an incremental collection.
 730     gch->do_collection(false            /* full */,
 731                        false            /* clear_all_soft_refs */,
 732                        size             /* size */,
 733                        is_tlab          /* is_tlab */,
 734                        number_of_generations() - 1 /* max_level */);
 735   } else {
 736     if (Verbose && PrintGCDetails) {
 737       gclog_or_tty->print(" :: Trying full because partial may fail :: ");
 738     }
 739     // Try a full collection; see delta for bug id 6266275
 740     // for the original code and why this has been simplified
 741     // with from-space allocation criteria modified and
 742     // such allocation moved out of the safepoint path.
 743     gch->do_collection(true             /* full */,
 744                        false            /* clear_all_soft_refs */,
 745                        size             /* size */,
 746                        is_tlab          /* is_tlab */,
 747                        number_of_generations() - 1 /* max_level */);
 748   }
 749 
 750   result = gch->attempt_allocation(size, is_tlab, false /*first_only*/);
 751 
 752   if (result != NULL) {
 753     assert(gch->is_in_reserved(result), "result not in heap");
 754     return result;
 755   }
 756 
 757   // OK, collection failed, try expansion.
 758   result = expand_heap_and_allocate(size, is_tlab);
 759   if (result != NULL) {
 760     return result;
 761   }
 762 
 763   // If we reach this point, we're really out of memory. Try every trick
 764   // we can to reclaim memory. Force collection of soft references. Force
 765   // a complete compaction of the heap. Any additional methods for finding
 766   // free memory should be here, especially if they are expensive. If this
 767   // attempt fails, an OOM exception will be thrown.
 768   {
 769     UIntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted
 770 
 771     gch->do_collection(true             /* full */,
 772                        true             /* clear_all_soft_refs */,
 773                        size             /* size */,
 774                        is_tlab          /* is_tlab */,
 775                        number_of_generations() - 1 /* max_level */);
 776   }
 777 
 778   result = gch->attempt_allocation(size, is_tlab, false /* first_only */);
 779   if (result != NULL) {
 780     assert(gch->is_in_reserved(result), "result not in heap");
 781     return result;
 782   }
 783 
 784   assert(!should_clear_all_soft_refs(),
 785     "Flag should have been handled and cleared prior to this point");
 786 
 787   // What else?  We might try synchronous finalization later.  If the total
 788   // space available is large enough for the allocation, then a more
 789   // complete compaction phase than we've tried so far might be
 790   // appropriate.
 791   return NULL;
 792 }
 793 
 794 MetaWord* CollectorPolicy::satisfy_failed_metadata_allocation(
 795                                                  ClassLoaderData* loader_data,
 796                                                  size_t word_size,
 797                                                  Metaspace::MetadataType mdtype) {
 798   uint loop_count = 0;
 799   uint gc_count = 0;
 800   uint full_gc_count = 0;
 801 
 802   assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");
 803 
 804   do {
 805     MetaWord* result = NULL;
 806     if (GC_locker::is_active_and_needs_gc()) {
 807       // If the GC_locker is active, just expand and allocate.
 808       // If that does not succeed, wait if this thread is not
 809       // in a critical section itself.
 810       result =
 811         loader_data->metaspace_non_null()->expand_and_allocate(word_size,
 812                                                                mdtype);
 813       if (result != NULL) {
 814         return result;
 815       }
 816       JavaThread* jthr = JavaThread::current();
 817       if (!jthr->in_critical()) {
 818         // Wait for JNI critical section to be exited
 819         GC_locker::stall_until_clear();
 820         // The GC invoked by the last thread leaving the critical
 821         // section will be a young collection and a full collection
 822         // is (currently) needed for unloading classes so continue
 823         // to the next iteration to get a full GC.
 824         continue;
 825       } else {
 826         if (CheckJNICalls) {
 827           fatal("Possible deadlock due to allocating while"
 828                 " in jni critical section");
 829         }
 830         return NULL;
 831       }
 832     }
 833 
 834     {  // Need lock to get self consistent gc_count's
 835       MutexLocker ml(Heap_lock);
 836       gc_count      = Universe::heap()->total_collections();
 837       full_gc_count = Universe::heap()->total_full_collections();
 838     }
 839 
 840     // Generate a VM operation
 841     VM_CollectForMetadataAllocation op(loader_data,
 842                                        word_size,
 843                                        mdtype,
 844                                        gc_count,
 845                                        full_gc_count,
 846                                        GCCause::_metadata_GC_threshold);
 847     VMThread::execute(&op);
 848 
 849     // If GC was locked out, try again.  Check
 850     // before checking success because the prologue
 851     // could have succeeded and the GC still have
 852     // been locked out.
 853     if (op.gc_locked()) {
 854       continue;
 855     }
 856 
 857     if (op.prologue_succeeded()) {
 858       return op.result();
 859     }
 860     loop_count++;
 861     if ((QueuedAllocationWarningCount > 0) &&
 862         (loop_count % QueuedAllocationWarningCount == 0)) {
 863       warning("satisfy_failed_metadata_allocation() retries %d times \n\t"
 864               " size=%d", loop_count, word_size);
 865     }
 866   } while (true);  // Until a GC is done
 867 }
 868 
 869 // Return true if any of the following is true:
 870 // . the allocation won't fit into the current young gen heap
 871 // . gc locker is occupied (jni critical section)
 872 // . heap memory is tight -- the most recent previous collection
 873 //   was a full collection because a partial collection (would
 874 //   have) failed and is likely to fail again
 875 bool GenCollectorPolicy::should_try_older_generation_allocation(
 876         size_t word_size) const {
 877   GenCollectedHeap* gch = GenCollectedHeap::heap();
 878   size_t gen0_capacity = gch->get_gen(0)->capacity_before_gc();
 879   return    (word_size > heap_word_size(gen0_capacity))
 880          || GC_locker::is_active_and_needs_gc()
 881          || gch->incremental_collection_failed();
 882 }
 883 
 884 
 885 //
 886 // MarkSweepPolicy methods
 887 //
 888 
 889 MarkSweepPolicy::MarkSweepPolicy() {
 890   initialize_all();
 891 }
 892 
 893 void MarkSweepPolicy::initialize_generations() {
 894   _generations = NEW_C_HEAP_ARRAY3(GenerationSpecPtr, number_of_generations(), mtGC, 0, AllocFailStrategy::RETURN_NULL);
 895   if (_generations == NULL)
 896     vm_exit_during_initialization("Unable to allocate gen spec");
 897 
 898   if (UseParNewGC) {
 899     _generations[0] = new GenerationSpec(Generation::ParNew, _initial_gen0_size, _max_gen0_size);
 900   } else {
 901     _generations[0] = new GenerationSpec(Generation::DefNew, _initial_gen0_size, _max_gen0_size);
 902   }
 903   _generations[1] = new GenerationSpec(Generation::MarkSweepCompact, _initial_gen1_size, _max_gen1_size);
 904 
 905   if (_generations[0] == NULL || _generations[1] == NULL)
 906     vm_exit_during_initialization("Unable to allocate gen spec");
 907 }
 908 
 909 void MarkSweepPolicy::initialize_gc_policy_counters() {
 910   // initialize the policy counters - 2 collectors, 3 generations
 911   if (UseParNewGC) {
 912     _gc_policy_counters = new GCPolicyCounters("ParNew:MSC", 2, 3);
 913   } else {
 914     _gc_policy_counters = new GCPolicyCounters("Copy:MSC", 2, 3);
 915   }
 916 }
--- EOF ---