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 CollectorPolicy::CollectorPolicy() :
  51     _space_alignment(0),
  52     _heap_alignment(0),
  53     _initial_heap_byte_size(InitialHeapSize),
  54     _max_heap_byte_size(MaxHeapSize),
  55     _min_heap_byte_size(Arguments::min_heap_size()),
  56     _max_heap_size_cmdline(false),
  57     _size_policy(NULL),
  58     _should_clear_all_soft_refs(false),
  59     _all_soft_refs_clear(false)
  60 {}
  61 
  62 #ifdef ASSERT
  63 void CollectorPolicy::assert_flags() {
  64   assert(InitialHeapSize <= MaxHeapSize, "Ergonomics decided on incompatible initial and maximum heap sizes");
  65   assert(InitialHeapSize % _heap_alignment == 0, "InitialHeapSize alignment");
  66   assert(MaxHeapSize % _heap_alignment == 0, "MaxHeapSize alignment");
  67 }
  68 
  69 void CollectorPolicy::assert_size_info() {
  70   assert(InitialHeapSize == _initial_heap_byte_size, "Discrepancy between InitialHeapSize flag and local storage");
  71   assert(MaxHeapSize == _max_heap_byte_size, "Discrepancy between MaxHeapSize flag and local storage");
  72   assert(_max_heap_byte_size >= _min_heap_byte_size, "Ergonomics decided on incompatible minimum and maximum heap sizes");
  73   assert(_initial_heap_byte_size >= _min_heap_byte_size, "Ergonomics decided on incompatible initial and minimum heap sizes");
  74   assert(_max_heap_byte_size >= _initial_heap_byte_size, "Ergonomics decided on incompatible initial and maximum heap sizes");
  75   assert(_min_heap_byte_size % _heap_alignment == 0, "min_heap_byte_size alignment");
  76   assert(_initial_heap_byte_size % _heap_alignment == 0, "initial_heap_byte_size alignment");
  77   assert(_max_heap_byte_size % _heap_alignment == 0, "max_heap_byte_size alignment");
  78 }
  79 #endif // ASSERT
  80 
  81 void CollectorPolicy::initialize_flags() {
  82   assert(_space_alignment != 0, "Space alignment not set up properly");
  83   assert(_heap_alignment != 0, "Heap alignment not set up properly");
  84   assert(_heap_alignment >= _space_alignment,
  85          err_msg("heap_alignment: " SIZE_FORMAT " less than space_alignment: " SIZE_FORMAT,
  86                  _heap_alignment, _space_alignment));
  87   assert(_heap_alignment % _space_alignment == 0,
  88          err_msg("heap_alignment: " SIZE_FORMAT " not aligned by space_alignment: " SIZE_FORMAT,
  89                  _heap_alignment, _space_alignment));
  90 
  91   if (FLAG_IS_CMDLINE(MaxHeapSize)) {
  92     if (FLAG_IS_CMDLINE(InitialHeapSize) && InitialHeapSize > MaxHeapSize) {
  93       vm_exit_during_initialization("Initial heap size set to a larger value than the maximum heap size");
  94     }
  95     if (_min_heap_byte_size != 0 && MaxHeapSize < _min_heap_byte_size) {
  96       vm_exit_during_initialization("Incompatible minimum and maximum heap sizes specified");
  97     }
  98     _max_heap_size_cmdline = true;
  99   }
 100 
 101   // Check heap parameter properties
 102   if (InitialHeapSize < M) {
 103     vm_exit_during_initialization("Too small initial heap");
 104   }
 105   if (_min_heap_byte_size < M) {
 106     vm_exit_during_initialization("Too small minimum heap");
 107   }
 108 
 109   // User inputs from -Xmx and -Xms must be aligned
 110   _min_heap_byte_size = align_size_up(_min_heap_byte_size, _heap_alignment);
 111   uintx aligned_initial_heap_size = align_size_up(InitialHeapSize, _heap_alignment);
 112   uintx aligned_max_heap_size = align_size_up(MaxHeapSize, _heap_alignment);
 113 
 114   // Write back to flags if the values changed
 115   if (aligned_initial_heap_size != InitialHeapSize) {
 116     FLAG_SET_ERGO(uintx, InitialHeapSize, aligned_initial_heap_size);
 117   }
 118   if (aligned_max_heap_size != MaxHeapSize) {
 119     FLAG_SET_ERGO(uintx, MaxHeapSize, aligned_max_heap_size);
 120   }
 121 
 122   if (FLAG_IS_CMDLINE(InitialHeapSize) && _min_heap_byte_size != 0 &&
 123       InitialHeapSize < _min_heap_byte_size) {
 124     vm_exit_during_initialization("Incompatible minimum and initial heap sizes specified");
 125   }
 126   if (!FLAG_IS_DEFAULT(InitialHeapSize) && InitialHeapSize > MaxHeapSize) {
 127     FLAG_SET_ERGO(uintx, MaxHeapSize, InitialHeapSize);
 128   } else if (!FLAG_IS_DEFAULT(MaxHeapSize) && InitialHeapSize > MaxHeapSize) {
 129     FLAG_SET_ERGO(uintx, InitialHeapSize, MaxHeapSize);
 130     if (InitialHeapSize < _min_heap_byte_size) {
 131       _min_heap_byte_size = InitialHeapSize;
 132     }
 133   }
 134 
 135   _initial_heap_byte_size = InitialHeapSize;
 136   _max_heap_byte_size = MaxHeapSize;
 137 
 138   FLAG_SET_ERGO(uintx, MinHeapDeltaBytes, align_size_up(MinHeapDeltaBytes, _space_alignment));
 139 
 140   DEBUG_ONLY(CollectorPolicy::assert_flags();)
 141 }
 142 
 143 void CollectorPolicy::initialize_size_info() {
 144   if (PrintGCDetails && Verbose) {
 145     gclog_or_tty->print_cr("Minimum heap " SIZE_FORMAT "  Initial heap "
 146       SIZE_FORMAT "  Maximum heap " SIZE_FORMAT,
 147       _min_heap_byte_size, _initial_heap_byte_size, _max_heap_byte_size);
 148   }
 149 
 150   DEBUG_ONLY(CollectorPolicy::assert_size_info();)
 151 }
 152 
 153 bool CollectorPolicy::use_should_clear_all_soft_refs(bool v) {
 154   bool result = _should_clear_all_soft_refs;
 155   set_should_clear_all_soft_refs(false);
 156   return result;
 157 }
 158 
 159 GenRemSet* CollectorPolicy::create_rem_set(MemRegion whole_heap,
 160                                            int max_covered_regions) {
 161   return new CardTableRS(whole_heap, max_covered_regions);
 162 }
 163 
 164 void CollectorPolicy::cleared_all_soft_refs() {
 165   // If near gc overhear limit, continue to clear SoftRefs.  SoftRefs may
 166   // have been cleared in the last collection but if the gc overhear
 167   // limit continues to be near, SoftRefs should still be cleared.
 168   if (size_policy() != NULL) {
 169     _should_clear_all_soft_refs = size_policy()->gc_overhead_limit_near();
 170   }
 171   _all_soft_refs_clear = true;
 172 }
 173 
 174 size_t CollectorPolicy::compute_heap_alignment() {
 175   // The card marking array and the offset arrays for old generations are
 176   // committed in os pages as well. Make sure they are entirely full (to
 177   // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1
 178   // byte entry and the os page size is 4096, the maximum heap size should
 179   // be 512*4096 = 2MB aligned.
 180 
 181   size_t alignment = GenRemSet::max_alignment_constraint();
 182 
 183   // Parallel GC does its own alignment of the generations to avoid requiring a
 184   // large page (256M on some platforms) for the permanent generation.  The
 185   // other collectors should also be updated to do their own alignment and then
 186   // this use of lcm() should be removed.
 187   if (UseLargePages && !UseParallelGC) {
 188       // In presence of large pages we have to make sure that our
 189       // alignment is large page aware
 190       alignment = lcm(os::large_page_size(), alignment);
 191   }
 192 
 193   return alignment;
 194 }
 195 
 196 // GenCollectorPolicy methods
 197 
 198 GenCollectorPolicy::GenCollectorPolicy() :
 199     _min_gen0_size(0),
 200     _initial_gen0_size(0),
 201     _max_gen0_size(0),
 202     _gen_alignment(0),
 203     _generations(NULL)
 204 {}
 205 
 206 size_t GenCollectorPolicy::scale_by_NewRatio_aligned(size_t base_size) {
 207   return align_size_down_bounded(base_size / (NewRatio + 1), _gen_alignment);
 208 }
 209 
 210 size_t GenCollectorPolicy::bound_minus_alignment(size_t desired_size,
 211                                                  size_t maximum_size) {
 212   size_t max_minus = maximum_size - _gen_alignment;
 213   return desired_size < max_minus ? desired_size : max_minus;
 214 }
 215 
 216 
 217 void GenCollectorPolicy::initialize_size_policy(size_t init_eden_size,
 218                                                 size_t init_promo_size,
 219                                                 size_t init_survivor_size) {
 220   const double max_gc_pause_sec = ((double) MaxGCPauseMillis) / 1000.0;
 221   _size_policy = new AdaptiveSizePolicy(init_eden_size,
 222                                         init_promo_size,
 223                                         init_survivor_size,
 224                                         max_gc_pause_sec,
 225                                         GCTimeRatio);
 226 }
 227 
 228 size_t GenCollectorPolicy::young_gen_size_lower_bound() {
 229   // The young generation must be aligned and have room for eden + two survivors
 230   return align_size_up(3 * _space_alignment, _gen_alignment);
 231 }
 232 
 233 #ifdef ASSERT
 234 void GenCollectorPolicy::assert_flags() {
 235   CollectorPolicy::assert_flags();
 236   assert(NewSize >= _min_gen0_size, "Ergonomics decided on a too small young gen size");
 237   assert(NewSize <= MaxNewSize, "Ergonomics decided on incompatible initial and maximum young gen sizes");
 238   assert(FLAG_IS_DEFAULT(MaxNewSize) || MaxNewSize < MaxHeapSize, "Ergonomics decided on incompatible maximum young gen and heap sizes");
 239   assert(NewSize % _gen_alignment == 0, "NewSize alignment");
 240   assert(FLAG_IS_DEFAULT(MaxNewSize) || MaxNewSize % _gen_alignment == 0, "MaxNewSize alignment");
 241 }
 242 
 243 void TwoGenerationCollectorPolicy::assert_flags() {
 244   GenCollectorPolicy::assert_flags();
 245   assert(OldSize + NewSize <= MaxHeapSize, "Ergonomics decided on incompatible generation and heap sizes");
 246   assert(OldSize % _gen_alignment == 0, "OldSize alignment");
 247 }
 248 
 249 void GenCollectorPolicy::assert_size_info() {
 250   CollectorPolicy::assert_size_info();
 251   // GenCollectorPolicy::initialize_size_info may update the MaxNewSize
 252   assert(MaxNewSize < MaxHeapSize, "Ergonomics decided on incompatible maximum young and heap sizes");
 253   assert(NewSize == _initial_gen0_size, "Discrepancy between NewSize flag and local storage");
 254   assert(MaxNewSize == _max_gen0_size, "Discrepancy between MaxNewSize flag and local storage");
 255   assert(_min_gen0_size <= _initial_gen0_size, "Ergonomics decided on incompatible minimum and initial young gen sizes");
 256   assert(_initial_gen0_size <= _max_gen0_size, "Ergonomics decided on incompatible initial and maximum young gen sizes");
 257   assert(_min_gen0_size % _gen_alignment == 0, "_min_gen0_size alignment");
 258   assert(_initial_gen0_size % _gen_alignment == 0, "_initial_gen0_size alignment");
 259   assert(_max_gen0_size % _gen_alignment == 0, "_max_gen0_size alignment");
 260 }
 261 
 262 void TwoGenerationCollectorPolicy::assert_size_info() {
 263   GenCollectorPolicy::assert_size_info();
 264   assert(OldSize == _initial_gen1_size, "Discrepancy between OldSize flag and local storage");
 265   assert(_min_gen1_size <= _initial_gen1_size, "Ergonomics decided on incompatible minimum and initial old gen sizes");
 266   assert(_initial_gen1_size <= _max_gen1_size, "Ergonomics decided on incompatible initial and maximum old gen sizes");
 267   assert(_max_gen1_size % _gen_alignment == 0, "_max_gen1_size alignment");
 268   assert(_initial_gen1_size % _gen_alignment == 0, "_initial_gen1_size alignment");
 269   assert(_max_heap_byte_size <= (_max_gen0_size + _max_gen1_size), "Total maximum heap sizes must be sum of generation maximum sizes");
 270 }
 271 #endif // ASSERT
 272 
 273 void GenCollectorPolicy::initialize_flags() {
 274   CollectorPolicy::initialize_flags();
 275 
 276   assert(_gen_alignment != 0, "Generation alignment not set up properly");
 277   assert(_heap_alignment >= _gen_alignment,
 278          err_msg("heap_alignment: " SIZE_FORMAT " less than gen_alignment: " SIZE_FORMAT,
 279                  _heap_alignment, _gen_alignment));
 280   assert(_gen_alignment % _space_alignment == 0,
 281          err_msg("gen_alignment: " SIZE_FORMAT " not aligned by space_alignment: " SIZE_FORMAT,
 282                  _gen_alignment, _space_alignment));
 283   assert(_heap_alignment % _gen_alignment == 0,
 284          err_msg("heap_alignment: " SIZE_FORMAT " not aligned by gen_alignment: " SIZE_FORMAT,
 285                  _heap_alignment, _gen_alignment));
 286 
 287   // All generational heaps have a youngest gen; handle those flags here
 288 
 289   // Make sure the heap is large enough for two generations
 290   uintx smallest_new_size = young_gen_size_lower_bound();
 291   uintx smallest_heap_size = align_size_up(smallest_new_size + align_size_up(_space_alignment, _gen_alignment),
 292                                            _heap_alignment);
 293   if (MaxHeapSize < smallest_heap_size) {
 294     FLAG_SET_ERGO(uintx, MaxHeapSize, smallest_heap_size);
 295     _max_heap_byte_size = MaxHeapSize;
 296   }
 297   // If needed, synchronize _min_heap_byte size and _initial_heap_byte_size
 298   if (_min_heap_byte_size < smallest_heap_size) {
 299     _min_heap_byte_size = smallest_heap_size;
 300     if (InitialHeapSize < _min_heap_byte_size) {
 301       FLAG_SET_ERGO(uintx, InitialHeapSize, smallest_heap_size);
 302       _initial_heap_byte_size = smallest_heap_size;
 303     }
 304   }
 305 
 306   // Now take the actual NewSize into account. We will silently increase NewSize
 307   // if the user specified a smaller value.
 308   smallest_new_size = MAX2(smallest_new_size, (uintx)align_size_down(NewSize, _gen_alignment));
 309   if (smallest_new_size != NewSize) {
 310     FLAG_SET_ERGO(uintx, NewSize, smallest_new_size);
 311   }
 312   _initial_gen0_size = NewSize;
 313 
 314   if (!FLAG_IS_DEFAULT(MaxNewSize)) {
 315     uintx min_new_size = MAX2(_gen_alignment, _min_gen0_size);
 316 
 317     if (MaxNewSize >= MaxHeapSize) {
 318       // Make sure there is room for an old generation
 319       uintx smaller_max_new_size = MaxHeapSize - _gen_alignment;
 320       if (FLAG_IS_CMDLINE(MaxNewSize)) {
 321         warning("MaxNewSize (" SIZE_FORMAT "k) is equal to or greater than the entire "
 322                 "heap (" SIZE_FORMAT "k).  A new max generation size of " SIZE_FORMAT "k will be used.",
 323                 MaxNewSize/K, MaxHeapSize/K, smaller_max_new_size/K);
 324       }
 325       FLAG_SET_ERGO(uintx, MaxNewSize, smaller_max_new_size);
 326       if (NewSize > MaxNewSize) {
 327         FLAG_SET_ERGO(uintx, NewSize, MaxNewSize);
 328         _initial_gen0_size = NewSize;
 329       }
 330     } else if (MaxNewSize < min_new_size) {
 331       FLAG_SET_ERGO(uintx, MaxNewSize, min_new_size);
 332     } else if (!is_size_aligned(MaxNewSize, _gen_alignment)) {
 333       FLAG_SET_ERGO(uintx, MaxNewSize, align_size_down(MaxNewSize, _gen_alignment));
 334     }
 335     _max_gen0_size = MaxNewSize;
 336   }
 337 
 338   if (NewSize > MaxNewSize) {
 339     // At this point this should only happen if the user specifies a large NewSize and/or
 340     // a small (but not too small) MaxNewSize.
 341     if (FLAG_IS_CMDLINE(MaxNewSize)) {
 342       warning("NewSize (" SIZE_FORMAT "k) is greater than the MaxNewSize (" SIZE_FORMAT "k). "
 343               "A new max generation size of " SIZE_FORMAT "k will be used.",
 344               NewSize/K, MaxNewSize/K, NewSize/K);
 345     }
 346     FLAG_SET_ERGO(uintx, MaxNewSize, NewSize);
 347     _max_gen0_size = MaxNewSize;
 348   }
 349 
 350   if (SurvivorRatio < 1 || NewRatio < 1) {
 351     vm_exit_during_initialization("Invalid young gen ratio specified");
 352   }
 353 
 354   DEBUG_ONLY(GenCollectorPolicy::assert_flags();)
 355 }
 356 
 357 void TwoGenerationCollectorPolicy::initialize_flags() {
 358   GenCollectorPolicy::initialize_flags();
 359 
 360   if (!is_size_aligned(OldSize, _gen_alignment)) {
 361     FLAG_SET_ERGO(uintx, OldSize, align_size_down(OldSize, _gen_alignment));
 362   }
 363 
 364   if (FLAG_IS_CMDLINE(OldSize) && FLAG_IS_DEFAULT(MaxHeapSize)) {
 365     // NewRatio will be used later to set the young generation size so we use
 366     // it to calculate how big the heap should be based on the requested OldSize
 367     // and NewRatio.
 368     assert(NewRatio > 0, "NewRatio should have been set up earlier");
 369     size_t calculated_heapsize = (OldSize / NewRatio) * (NewRatio + 1);
 370 
 371     calculated_heapsize = align_size_up(calculated_heapsize, _heap_alignment);
 372     FLAG_SET_ERGO(uintx, MaxHeapSize, calculated_heapsize);
 373     _max_heap_byte_size = MaxHeapSize;
 374     FLAG_SET_ERGO(uintx, InitialHeapSize, calculated_heapsize);
 375     _initial_heap_byte_size = InitialHeapSize;
 376   }
 377 
 378   // Adjust NewSize and OldSize or MaxHeapSize to match each other
 379   if (NewSize + OldSize > MaxHeapSize) {
 380     if (_max_heap_size_cmdline) {
 381       // Somebody has set a maximum heap size with the intention that we should not
 382       // exceed it. Adjust New/OldSize as necessary.
 383       uintx calculated_size = NewSize + OldSize;
 384       double shrink_factor = (double) MaxHeapSize / calculated_size;
 385       uintx smaller_new_size = align_size_down((uintx)(NewSize * shrink_factor), _gen_alignment);
 386       FLAG_SET_ERGO(uintx, NewSize, MAX2(young_gen_size_lower_bound(), smaller_new_size));
 387       _initial_gen0_size = NewSize;
 388 
 389       // OldSize is already aligned because above we aligned MaxHeapSize to
 390       // _heap_alignment, and we just made sure that NewSize is aligned to
 391       // _gen_alignment. In initialize_flags() we verified that _heap_alignment
 392       // is a multiple of _gen_alignment.
 393       FLAG_SET_ERGO(uintx, OldSize, MaxHeapSize - NewSize);
 394     } else {
 395       FLAG_SET_ERGO(uintx, MaxHeapSize, align_size_up(NewSize + OldSize, _heap_alignment));
 396       _max_heap_byte_size = MaxHeapSize;
 397     }
 398   }
 399 
 400   always_do_update_barrier = UseConcMarkSweepGC;
 401 
 402   DEBUG_ONLY(TwoGenerationCollectorPolicy::assert_flags();)
 403 }
 404 
 405 // Values set on the command line win over any ergonomically
 406 // set command line parameters.
 407 // Ergonomic choice of parameters are done before this
 408 // method is called.  Values for command line parameters such as NewSize
 409 // and MaxNewSize feed those ergonomic choices into this method.
 410 // This method makes the final generation sizings consistent with
 411 // themselves and with overall heap sizings.
 412 // In the absence of explicitly set command line flags, policies
 413 // such as the use of NewRatio are used to size the generation.
 414 void GenCollectorPolicy::initialize_size_info() {
 415   CollectorPolicy::initialize_size_info();
 416 
 417   // _space_alignment is used for alignment within a generation.
 418   // There is additional alignment done down stream for some
 419   // collectors that sometimes causes unwanted rounding up of
 420   // generations sizes.
 421 
 422   // Determine maximum size of gen0
 423 
 424   size_t max_new_size = 0;
 425   if (!FLAG_IS_DEFAULT(MaxNewSize)) {
 426     max_new_size = MaxNewSize;
 427   } else {
 428     max_new_size = scale_by_NewRatio_aligned(_max_heap_byte_size);
 429     // Bound the maximum size by NewSize below (since it historically
 430     // would have been NewSize and because the NewRatio calculation could
 431     // yield a size that is too small) and bound it by MaxNewSize above.
 432     // Ergonomics plays here by previously calculating the desired
 433     // NewSize and MaxNewSize.
 434     max_new_size = MIN2(MAX2(max_new_size, NewSize), MaxNewSize);
 435   }
 436   assert(max_new_size > 0, "All paths should set max_new_size");
 437 
 438   // Given the maximum gen0 size, determine the initial and
 439   // minimum gen0 sizes.
 440 
 441   if (_max_heap_byte_size == _min_heap_byte_size) {
 442     // The maximum and minimum heap sizes are the same so the generations
 443     // minimum and initial must be the same as its maximum.
 444     _min_gen0_size = max_new_size;
 445     _initial_gen0_size = max_new_size;
 446     _max_gen0_size = max_new_size;
 447   } else {
 448     size_t desired_new_size = 0;
 449     if (FLAG_IS_CMDLINE(NewSize)) {
 450       // If NewSize is set on the command line, we must use it as
 451       // the initial size and it also makes sense to use it as the
 452       // lower limit.
 453       _min_gen0_size = NewSize;
 454       desired_new_size = NewSize;
 455       max_new_size = MAX2(max_new_size, NewSize);
 456     } else if (FLAG_IS_ERGO(NewSize)) {
 457       // If NewSize is set ergonomically, we should use it as a lower
 458       // limit, but use NewRatio to calculate the initial size.
 459       _min_gen0_size = NewSize;
 460       desired_new_size =
 461         MAX2(scale_by_NewRatio_aligned(_initial_heap_byte_size), NewSize);
 462       max_new_size = MAX2(max_new_size, NewSize);
 463     } else {
 464       // For the case where NewSize is the default, use NewRatio
 465       // to size the minimum and initial generation sizes.
 466       // Use the default NewSize as the floor for these values.  If
 467       // NewRatio is overly large, the resulting sizes can be too small.
 468       _min_gen0_size = MAX2(scale_by_NewRatio_aligned(_min_heap_byte_size), NewSize);
 469       desired_new_size =
 470         MAX2(scale_by_NewRatio_aligned(_initial_heap_byte_size), NewSize);
 471     }
 472 
 473     assert(_min_gen0_size > 0, "Sanity check");
 474     _initial_gen0_size = desired_new_size;
 475     _max_gen0_size = max_new_size;
 476 
 477     // At this point the desirable initial and minimum sizes have been
 478     // determined without regard to the maximum sizes.
 479 
 480     // Bound the sizes by the corresponding overall heap sizes.
 481     _min_gen0_size = bound_minus_alignment(_min_gen0_size, _min_heap_byte_size);
 482     _initial_gen0_size = bound_minus_alignment(_initial_gen0_size, _initial_heap_byte_size);
 483     _max_gen0_size = bound_minus_alignment(_max_gen0_size, _max_heap_byte_size);
 484 
 485     // At this point all three sizes have been checked against the
 486     // maximum sizes but have not been checked for consistency among the three.
 487 
 488     // Final check min <= initial <= max
 489     _min_gen0_size = MIN2(_min_gen0_size, _max_gen0_size);
 490     _initial_gen0_size = MAX2(MIN2(_initial_gen0_size, _max_gen0_size), _min_gen0_size);
 491     _min_gen0_size = MIN2(_min_gen0_size, _initial_gen0_size);
 492   }
 493 
 494   // Write back to flags if necessary.
 495   if (NewSize != _initial_gen0_size) {
 496     FLAG_SET_ERGO(uintx, NewSize, _initial_gen0_size);
 497   }
 498 
 499   if (MaxNewSize != _max_gen0_size) {
 500     FLAG_SET_ERGO(uintx, MaxNewSize, _max_gen0_size);
 501   }
 502 
 503   if (PrintGCDetails && Verbose) {
 504     gclog_or_tty->print_cr("1: Minimum gen0 " SIZE_FORMAT "  Initial gen0 "
 505       SIZE_FORMAT "  Maximum gen0 " SIZE_FORMAT,
 506       _min_gen0_size, _initial_gen0_size, _max_gen0_size);
 507   }
 508 
 509   DEBUG_ONLY(GenCollectorPolicy::assert_size_info();)
 510 }
 511 
 512 // Call this method during the sizing of the gen1 to make
 513 // adjustments to gen0 because of gen1 sizing policy.  gen0 initially has
 514 // the most freedom in sizing because it is done before the
 515 // policy for gen1 is applied.  Once gen1 policies have been applied,
 516 // there may be conflicts in the shape of the heap and this method
 517 // is used to make the needed adjustments.  The application of the
 518 // policies could be more sophisticated (iterative for example) but
 519 // keeping it simple also seems a worthwhile goal.
 520 bool TwoGenerationCollectorPolicy::adjust_gen0_sizes(size_t* gen0_size_ptr,
 521                                                      size_t* gen1_size_ptr,
 522                                                      const size_t heap_size) {
 523   bool result = false;
 524 
 525   if ((*gen0_size_ptr + *gen1_size_ptr) > heap_size) {
 526     uintx smallest_new_size = young_gen_size_lower_bound();
 527     if ((heap_size < (*gen0_size_ptr + _min_gen1_size)) &&
 528         (heap_size >= _min_gen1_size + smallest_new_size)) {
 529       // Adjust gen0 down to accommodate _min_gen1_size
 530       *gen0_size_ptr = align_size_down_bounded(heap_size - _min_gen1_size, _gen_alignment);
 531       result = true;
 532     } else {
 533       *gen1_size_ptr = align_size_down_bounded(heap_size - *gen0_size_ptr, _gen_alignment);
 534     }
 535   }
 536   return result;
 537 }
 538 
 539 // Minimum sizes of the generations may be different than
 540 // the initial sizes.  An inconsistency is permitted here
 541 // in the total size that can be specified explicitly by
 542 // command line specification of OldSize and NewSize and
 543 // also a command line specification of -Xms.  Issue a warning
 544 // but allow the values to pass.
 545 
 546 void TwoGenerationCollectorPolicy::initialize_size_info() {
 547   GenCollectorPolicy::initialize_size_info();
 548 
 549   // At this point the minimum, initial and maximum sizes
 550   // of the overall heap and of gen0 have been determined.
 551   // The maximum gen1 size can be determined from the maximum gen0
 552   // and maximum heap size since no explicit flags exist
 553   // for setting the gen1 maximum.
 554   _max_gen1_size = MAX2(_max_heap_byte_size - _max_gen0_size, _gen_alignment);
 555 
 556   // If no explicit command line flag has been set for the
 557   // gen1 size, use what is left for gen1
 558   if (!FLAG_IS_CMDLINE(OldSize)) {
 559     // The user has not specified any value but the ergonomics
 560     // may have chosen a value (which may or may not be consistent
 561     // with the overall heap size).  In either case make
 562     // the minimum, maximum and initial sizes consistent
 563     // with the gen0 sizes and the overall heap sizes.
 564     _min_gen1_size = MAX2(_min_heap_byte_size - _min_gen0_size, _gen_alignment);
 565     _initial_gen1_size = MAX2(_initial_heap_byte_size - _initial_gen0_size, _gen_alignment);
 566     // _max_gen1_size has already been made consistent above
 567     FLAG_SET_ERGO(uintx, OldSize, _initial_gen1_size);
 568   } else {
 569     // OldSize has been explicitly set on the command line. Use the
 570     // OldSize and then determine the consequences.
 571     _min_gen1_size = MIN2(OldSize, _min_heap_byte_size - _min_gen0_size);
 572     _initial_gen1_size = OldSize;
 573 
 574     // If the user has explicitly set an OldSize that is inconsistent
 575     // with other command line flags, issue a warning.
 576     // The generation minimums and the overall heap minimum should
 577     // be within one generation alignment.
 578     if ((_min_gen1_size + _min_gen0_size + _gen_alignment) < _min_heap_byte_size) {
 579       warning("Inconsistency between minimum heap size and minimum "
 580               "generation sizes: using minimum heap = " SIZE_FORMAT,
 581               _min_heap_byte_size);
 582     }
 583     if (OldSize > _max_gen1_size) {
 584       warning("Inconsistency between maximum heap size and maximum "
 585               "generation sizes: using maximum heap = " SIZE_FORMAT
 586               " -XX:OldSize flag is being ignored",
 587               _max_heap_byte_size);
 588     }
 589     // If there is an inconsistency between the OldSize and the minimum and/or
 590     // initial size of gen0, since OldSize was explicitly set, OldSize wins.
 591     if (adjust_gen0_sizes(&_min_gen0_size, &_min_gen1_size, _min_heap_byte_size)) {
 592       if (PrintGCDetails && Verbose) {
 593         gclog_or_tty->print_cr("2: Minimum gen0 " SIZE_FORMAT "  Initial gen0 "
 594               SIZE_FORMAT "  Maximum gen0 " SIZE_FORMAT,
 595               _min_gen0_size, _initial_gen0_size, _max_gen0_size);
 596       }
 597     }
 598     // The same as above for the old gen initial size.
 599     if (adjust_gen0_sizes(&_initial_gen0_size, &_initial_gen1_size,
 600                           _initial_heap_byte_size)) {
 601       if (PrintGCDetails && Verbose) {
 602         gclog_or_tty->print_cr("3: Minimum gen0 " SIZE_FORMAT "  Initial gen0 "
 603           SIZE_FORMAT "  Maximum gen0 " SIZE_FORMAT,
 604           _min_gen0_size, _initial_gen0_size, _max_gen0_size);
 605       }
 606     }
 607   }
 608 
 609   _min_gen1_size = MIN2(_min_gen1_size, _max_gen1_size);
 610 
 611   // Make sure that min gen1 <= initial gen1 <= max gen1.
 612   _initial_gen1_size = MAX2(_initial_gen1_size, _min_gen1_size);
 613   _initial_gen1_size = MIN2(_initial_gen1_size, _max_gen1_size);
 614 
 615   // Write back to flags if necessary
 616   if (NewSize != _initial_gen0_size) {
 617     FLAG_SET_ERGO(uintx, NewSize, _initial_gen0_size);
 618   }
 619 
 620   if (MaxNewSize != _max_gen0_size) {
 621     FLAG_SET_ERGO(uintx, MaxNewSize, _max_gen0_size);
 622   }
 623 
 624   if (OldSize != _initial_gen1_size) {
 625     FLAG_SET_ERGO(uintx, OldSize, _initial_gen1_size);
 626   }
 627 
 628   if (PrintGCDetails && Verbose) {
 629     gclog_or_tty->print_cr("Minimum gen1 " SIZE_FORMAT "  Initial gen1 "
 630       SIZE_FORMAT "  Maximum gen1 " SIZE_FORMAT,
 631       _min_gen1_size, _initial_gen1_size, _max_gen1_size);
 632   }
 633 
 634   DEBUG_ONLY(TwoGenerationCollectorPolicy::assert_size_info();)
 635 }
 636 
 637 HeapWord* GenCollectorPolicy::mem_allocate_work(size_t size,
 638                                         bool is_tlab,
 639                                         bool* gc_overhead_limit_was_exceeded) {
 640   GenCollectedHeap *gch = GenCollectedHeap::heap();
 641 
 642   debug_only(gch->check_for_valid_allocation_state());
 643   assert(gch->no_gc_in_progress(), "Allocation during gc not allowed");
 644 
 645   // In general gc_overhead_limit_was_exceeded should be false so
 646   // set it so here and reset it to true only if the gc time
 647   // limit is being exceeded as checked below.
 648   *gc_overhead_limit_was_exceeded = false;
 649 
 650   HeapWord* result = NULL;
 651 
 652   // Loop until the allocation is satisfied, or unsatisfied after GC.
 653   for (int try_count = 1, gclocker_stalled_count = 0; /* return or throw */; try_count += 1) {
 654     HandleMark hm; // Discard any handles allocated in each iteration.
 655 
 656     // First allocation attempt is lock-free.
 657     Generation *gen0 = gch->get_gen(0);
 658     assert(gen0->supports_inline_contig_alloc(),
 659       "Otherwise, must do alloc within heap lock");
 660     if (gen0->should_allocate(size, is_tlab)) {
 661       result = gen0->par_allocate(size, is_tlab);
 662       if (result != NULL) {
 663         assert(gch->is_in_reserved(result), "result not in heap");
 664         return result;
 665       }
 666     }
 667     unsigned int gc_count_before;  // Read inside the Heap_lock locked region.
 668     {
 669       MutexLocker ml(Heap_lock);
 670       if (PrintGC && Verbose) {
 671         gclog_or_tty->print_cr("TwoGenerationCollectorPolicy::mem_allocate_work:"
 672                       " attempting locked slow path allocation");
 673       }
 674       // Note that only large objects get a shot at being
 675       // allocated in later generations.
 676       bool first_only = ! should_try_older_generation_allocation(size);
 677 
 678       result = gch->attempt_allocation(size, is_tlab, first_only);
 679       if (result != NULL) {
 680         assert(gch->is_in_reserved(result), "result not in heap");
 681         return result;
 682       }
 683 
 684       if (GC_locker::is_active_and_needs_gc()) {
 685         if (is_tlab) {
 686           return NULL;  // Caller will retry allocating individual object.
 687         }
 688         if (!gch->is_maximal_no_gc()) {
 689           // Try and expand heap to satisfy request.
 690           result = expand_heap_and_allocate(size, is_tlab);
 691           // Result could be null if we are out of space.
 692           if (result != NULL) {
 693             return result;
 694           }
 695         }
 696 
 697         if (gclocker_stalled_count > GCLockerRetryAllocationCount) {
 698           return NULL; // We didn't get to do a GC and we didn't get any memory.
 699         }
 700 
 701         // If this thread is not in a jni critical section, we stall
 702         // the requestor until the critical section has cleared and
 703         // GC allowed. When the critical section clears, a GC is
 704         // initiated by the last thread exiting the critical section; so
 705         // we retry the allocation sequence from the beginning of the loop,
 706         // rather than causing more, now probably unnecessary, GC attempts.
 707         JavaThread* jthr = JavaThread::current();
 708         if (!jthr->in_critical()) {
 709           MutexUnlocker mul(Heap_lock);
 710           // Wait for JNI critical section to be exited
 711           GC_locker::stall_until_clear();
 712           gclocker_stalled_count += 1;
 713           continue;
 714         } else {
 715           if (CheckJNICalls) {
 716             fatal("Possible deadlock due to allocating while"
 717                   " in jni critical section");
 718           }
 719           return NULL;
 720         }
 721       }
 722 
 723       // Read the gc count while the heap lock is held.
 724       gc_count_before = Universe::heap()->total_collections();
 725     }
 726 
 727     VM_GenCollectForAllocation op(size, is_tlab, gc_count_before);
 728     VMThread::execute(&op);
 729     if (op.prologue_succeeded()) {
 730       result = op.result();
 731       if (op.gc_locked()) {
 732          assert(result == NULL, "must be NULL if gc_locked() is true");
 733          continue;  // Retry and/or stall as necessary.
 734       }
 735 
 736       // Allocation has failed and a collection
 737       // has been done.  If the gc time limit was exceeded the
 738       // this time, return NULL so that an out-of-memory
 739       // will be thrown.  Clear gc_overhead_limit_exceeded
 740       // so that the overhead exceeded does not persist.
 741 
 742       const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded();
 743       const bool softrefs_clear = all_soft_refs_clear();
 744 
 745       if (limit_exceeded && softrefs_clear) {
 746         *gc_overhead_limit_was_exceeded = true;
 747         size_policy()->set_gc_overhead_limit_exceeded(false);
 748         if (op.result() != NULL) {
 749           CollectedHeap::fill_with_object(op.result(), size);
 750         }
 751         return NULL;
 752       }
 753       assert(result == NULL || gch->is_in_reserved(result),
 754              "result not in heap");
 755       return result;
 756     }
 757 
 758     // Give a warning if we seem to be looping forever.
 759     if ((QueuedAllocationWarningCount > 0) &&
 760         (try_count % QueuedAllocationWarningCount == 0)) {
 761           warning("TwoGenerationCollectorPolicy::mem_allocate_work retries %d times \n\t"
 762                   " size=%d %s", try_count, size, is_tlab ? "(TLAB)" : "");
 763     }
 764   }
 765 }
 766 
 767 HeapWord* GenCollectorPolicy::expand_heap_and_allocate(size_t size,
 768                                                        bool   is_tlab) {
 769   GenCollectedHeap *gch = GenCollectedHeap::heap();
 770   HeapWord* result = NULL;
 771   for (int i = number_of_generations() - 1; i >= 0 && result == NULL; i--) {
 772     Generation *gen = gch->get_gen(i);
 773     if (gen->should_allocate(size, is_tlab)) {
 774       result = gen->expand_and_allocate(size, is_tlab);
 775     }
 776   }
 777   assert(result == NULL || gch->is_in_reserved(result), "result not in heap");
 778   return result;
 779 }
 780 
 781 HeapWord* GenCollectorPolicy::satisfy_failed_allocation(size_t size,
 782                                                         bool   is_tlab) {
 783   GenCollectedHeap *gch = GenCollectedHeap::heap();
 784   GCCauseSetter x(gch, GCCause::_allocation_failure);
 785   HeapWord* result = NULL;
 786 
 787   assert(size != 0, "Precondition violated");
 788   if (GC_locker::is_active_and_needs_gc()) {
 789     // GC locker is active; instead of a collection we will attempt
 790     // to expand the heap, if there's room for expansion.
 791     if (!gch->is_maximal_no_gc()) {
 792       result = expand_heap_and_allocate(size, is_tlab);
 793     }
 794     return result;   // Could be null if we are out of space.
 795   } else if (!gch->incremental_collection_will_fail(false /* don't consult_young */)) {
 796     // Do an incremental collection.
 797     gch->do_collection(false            /* full */,
 798                        false            /* clear_all_soft_refs */,
 799                        size             /* size */,
 800                        is_tlab          /* is_tlab */,
 801                        number_of_generations() - 1 /* max_level */);
 802   } else {
 803     if (Verbose && PrintGCDetails) {
 804       gclog_or_tty->print(" :: Trying full because partial may fail :: ");
 805     }
 806     // Try a full collection; see delta for bug id 6266275
 807     // for the original code and why this has been simplified
 808     // with from-space allocation criteria modified and
 809     // such allocation moved out of the safepoint path.
 810     gch->do_collection(true             /* full */,
 811                        false            /* clear_all_soft_refs */,
 812                        size             /* size */,
 813                        is_tlab          /* is_tlab */,
 814                        number_of_generations() - 1 /* max_level */);
 815   }
 816 
 817   result = gch->attempt_allocation(size, is_tlab, false /*first_only*/);
 818 
 819   if (result != NULL) {
 820     assert(gch->is_in_reserved(result), "result not in heap");
 821     return result;
 822   }
 823 
 824   // OK, collection failed, try expansion.
 825   result = expand_heap_and_allocate(size, is_tlab);
 826   if (result != NULL) {
 827     return result;
 828   }
 829 
 830   // If we reach this point, we're really out of memory. Try every trick
 831   // we can to reclaim memory. Force collection of soft references. Force
 832   // a complete compaction of the heap. Any additional methods for finding
 833   // free memory should be here, especially if they are expensive. If this
 834   // attempt fails, an OOM exception will be thrown.
 835   {
 836     UIntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted
 837 
 838     gch->do_collection(true             /* full */,
 839                        true             /* clear_all_soft_refs */,
 840                        size             /* size */,
 841                        is_tlab          /* is_tlab */,
 842                        number_of_generations() - 1 /* max_level */);
 843   }
 844 
 845   result = gch->attempt_allocation(size, is_tlab, false /* first_only */);
 846   if (result != NULL) {
 847     assert(gch->is_in_reserved(result), "result not in heap");
 848     return result;
 849   }
 850 
 851   assert(!should_clear_all_soft_refs(),
 852     "Flag should have been handled and cleared prior to this point");
 853 
 854   // What else?  We might try synchronous finalization later.  If the total
 855   // space available is large enough for the allocation, then a more
 856   // complete compaction phase than we've tried so far might be
 857   // appropriate.
 858   return NULL;
 859 }
 860 
 861 MetaWord* CollectorPolicy::satisfy_failed_metadata_allocation(
 862                                                  ClassLoaderData* loader_data,
 863                                                  size_t word_size,
 864                                                  Metaspace::MetadataType mdtype) {
 865   uint loop_count = 0;
 866   uint gc_count = 0;
 867   uint full_gc_count = 0;
 868 
 869   assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");
 870 
 871   do {
 872     MetaWord* result = NULL;
 873     if (GC_locker::is_active_and_needs_gc()) {
 874       // If the GC_locker is active, just expand and allocate.
 875       // If that does not succeed, wait if this thread is not
 876       // in a critical section itself.
 877       result =
 878         loader_data->metaspace_non_null()->expand_and_allocate(word_size,
 879                                                                mdtype);
 880       if (result != NULL) {
 881         return result;
 882       }
 883       JavaThread* jthr = JavaThread::current();
 884       if (!jthr->in_critical()) {
 885         // Wait for JNI critical section to be exited
 886         GC_locker::stall_until_clear();
 887         // The GC invoked by the last thread leaving the critical
 888         // section will be a young collection and a full collection
 889         // is (currently) needed for unloading classes so continue
 890         // to the next iteration to get a full GC.
 891         continue;
 892       } else {
 893         if (CheckJNICalls) {
 894           fatal("Possible deadlock due to allocating while"
 895                 " in jni critical section");
 896         }
 897         return NULL;
 898       }
 899     }
 900 
 901     {  // Need lock to get self consistent gc_count's
 902       MutexLocker ml(Heap_lock);
 903       gc_count      = Universe::heap()->total_collections();
 904       full_gc_count = Universe::heap()->total_full_collections();
 905     }
 906 
 907     // Generate a VM operation
 908     VM_CollectForMetadataAllocation op(loader_data,
 909                                        word_size,
 910                                        mdtype,
 911                                        gc_count,
 912                                        full_gc_count,
 913                                        GCCause::_metadata_GC_threshold);
 914     VMThread::execute(&op);
 915 
 916     // If GC was locked out, try again. Check before checking success because the
 917     // prologue could have succeeded and the GC still have been locked out.
 918     if (op.gc_locked()) {
 919       continue;
 920     }
 921 
 922     if (op.prologue_succeeded()) {
 923       return op.result();
 924     }
 925     loop_count++;
 926     if ((QueuedAllocationWarningCount > 0) &&
 927         (loop_count % QueuedAllocationWarningCount == 0)) {
 928       warning("satisfy_failed_metadata_allocation() retries %d times \n\t"
 929               " size=%d", loop_count, word_size);
 930     }
 931   } while (true);  // Until a GC is done
 932 }
 933 
 934 // Return true if any of the following is true:
 935 // . the allocation won't fit into the current young gen heap
 936 // . gc locker is occupied (jni critical section)
 937 // . heap memory is tight -- the most recent previous collection
 938 //   was a full collection because a partial collection (would
 939 //   have) failed and is likely to fail again
 940 bool GenCollectorPolicy::should_try_older_generation_allocation(
 941         size_t word_size) const {
 942   GenCollectedHeap* gch = GenCollectedHeap::heap();
 943   size_t gen0_capacity = gch->get_gen(0)->capacity_before_gc();
 944   return    (word_size > heap_word_size(gen0_capacity))
 945          || GC_locker::is_active_and_needs_gc()
 946          || gch->incremental_collection_failed();
 947 }
 948 
 949 
 950 //
 951 // MarkSweepPolicy methods
 952 //
 953 
 954 void MarkSweepPolicy::initialize_alignments() {
 955   _space_alignment = _gen_alignment = (uintx)Generation::GenGrain;
 956   _heap_alignment = compute_heap_alignment();
 957 }
 958 
 959 void MarkSweepPolicy::initialize_generations() {
 960   _generations = NEW_C_HEAP_ARRAY3(GenerationSpecPtr, number_of_generations(), mtGC, 0, AllocFailStrategy::RETURN_NULL);
 961   if (_generations == NULL) {
 962     vm_exit_during_initialization("Unable to allocate gen spec");
 963   }
 964 
 965   if (UseParNewGC) {
 966     _generations[0] = new GenerationSpec(Generation::ParNew, _initial_gen0_size, _max_gen0_size);
 967   } else {
 968     _generations[0] = new GenerationSpec(Generation::DefNew, _initial_gen0_size, _max_gen0_size);
 969   }
 970   _generations[1] = new GenerationSpec(Generation::MarkSweepCompact, _initial_gen1_size, _max_gen1_size);
 971 
 972   if (_generations[0] == NULL || _generations[1] == NULL) {
 973     vm_exit_during_initialization("Unable to allocate gen spec");
 974   }
 975 }
 976 
 977 void MarkSweepPolicy::initialize_gc_policy_counters() {
 978   // Initialize the policy counters - 2 collectors, 3 generations.
 979   if (UseParNewGC) {
 980     _gc_policy_counters = new GCPolicyCounters("ParNew:MSC", 2, 3);
 981   } else {
 982     _gc_policy_counters = new GCPolicyCounters("Copy:MSC", 2, 3);
 983   }
 984 }
 985 
 986 /////////////// Unit tests ///////////////
 987 
 988 #ifndef PRODUCT
 989 // Testing that the NewSize flag is handled correct is hard because it
 990 // depends on so many other configurable variables. This test only tries to
 991 // verify that there are some basic rules for NewSize honored by the policies.
 992 class TestGenCollectorPolicy {
 993 public:
 994   static void test() {
 995     size_t flag_value;
 996 
 997     save_flags();
 998 
 999     // Set some limits that makes the math simple.
1000     FLAG_SET_ERGO(uintx, MaxHeapSize, 180 * M);
1001     FLAG_SET_ERGO(uintx, InitialHeapSize, 120 * M);
1002     Arguments::set_min_heap_size(40*M);
1003 
1004     // if NewSize set on command line should take for both min
1005     // and initial if less than min heap.
1006     flag_value = 20 * M;
1007     FLAG_SET_CMDLINE(uintx, NewSize, flag_value);
1008     verify_min(flag_value);
1009     verify_initial(flag_value);
1010 
1011     // If NewSize set on command line is set larger
1012     // than min heap size it will only take for initial.
1013     flag_value = 80*M;
1014     FLAG_SET_CMDLINE(uintx, NewSize, flag_value);
1015     verify_initial(flag_value);
1016 
1017     // If NewSize has been ergonomically set, the collector
1018     // policy should use it for min but calculate the initial
1019     // using NewRatio.
1020     flag_value = 20*M;
1021     FLAG_SET_ERGO(uintx, NewSize, flag_value);
1022     verify_min(flag_value);
1023     verify_scaled_initial(InitialHeapSize);
1024 
1025     restore_flags();
1026 
1027   }
1028 
1029   static void verify_min(size_t expected) {
1030     MarkSweepPolicy msp;
1031     msp.initialize_all();
1032 
1033     assert(msp.min_gen0_size() <= expected, err_msg("%zu  > %zu", msp.min_gen0_size(), expected));
1034   }
1035 
1036   static void verify_initial(size_t expected) {
1037     MarkSweepPolicy msp;
1038     msp.initialize_all();
1039 
1040     assert(msp.initial_gen0_size() == expected, err_msg("%zu != %zu", msp.initial_gen0_size(), expected));
1041   }
1042 
1043   static void verify_scaled_initial(size_t initial_heap_size) {
1044     MarkSweepPolicy msp;
1045     msp.initialize_all();
1046 
1047     size_t expected = msp.scale_by_NewRatio_aligned(initial_heap_size);
1048     assert(msp.initial_gen0_size() == expected, err_msg("%zu != %zu", msp.initial_gen0_size(), expected));
1049   }
1050 
1051 private:
1052   static size_t original_InitialHeapSize;
1053   static size_t original_MaxHeapSize;
1054   static size_t original_MaxNewSize;
1055   static size_t original_MinHeapDeltaBytes;
1056   static size_t original_NewSize;
1057   static size_t original_OldSize;
1058 
1059   static void save_flags() {
1060     original_InitialHeapSize   = InitialHeapSize;
1061     original_MaxHeapSize       = MaxHeapSize;
1062     original_MaxNewSize        = MaxNewSize;
1063     original_MinHeapDeltaBytes = MinHeapDeltaBytes;
1064     original_NewSize           = NewSize;
1065     original_OldSize           = OldSize;
1066   }
1067 
1068   static void restore_flags() {
1069     InitialHeapSize   = original_InitialHeapSize;
1070     MaxHeapSize       = original_MaxHeapSize;
1071     MaxNewSize        = original_MaxNewSize;
1072     MinHeapDeltaBytes = original_MinHeapDeltaBytes;
1073     NewSize           = original_NewSize;
1074     OldSize           = original_OldSize;
1075   }
1076 };
1077 
1078 size_t TestGenCollectorPolicy::original_InitialHeapSize   = 0;
1079 size_t TestGenCollectorPolicy::original_MaxHeapSize       = 0;
1080 size_t TestGenCollectorPolicy::original_MaxNewSize        = 0;
1081 size_t TestGenCollectorPolicy::original_MinHeapDeltaBytes = 0;
1082 size_t TestGenCollectorPolicy::original_NewSize           = 0;
1083 size_t TestGenCollectorPolicy::original_OldSize           = 0;
1084 
1085 void TestNewSize_test() {
1086   TestGenCollectorPolicy::test();
1087 }
1088 
1089 #endif