jdk8-mips64-public/hotspot: src/share/vm/memory/collectorPolicy.cpp@04ff2f6cd0eb (annotated)

src/share/vm/memory/collectorPolicy.cpp@04ff2f6cd0eb (annotated)

src/share/vm/memory/collectorPolicy.cpp

Tue, 17 Oct 2017 12:58:25 +0800

author: aoqi
date: Tue, 17 Oct 2017 12:58:25 +0800
changeset 7994: 04ff2f6cd0eb
parent 7686: fb69749583e8
parent 7535: 7ae4e26cb1e0
permissions: -rw-r--r--

merge

 /*
  * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #include "precompiled.hpp"
 #include "gc_implementation/shared/adaptiveSizePolicy.hpp"
 #include "gc_implementation/shared/gcPolicyCounters.hpp"
 #include "gc_implementation/shared/vmGCOperations.hpp"
 #include "memory/cardTableRS.hpp"
 #include "memory/collectorPolicy.hpp"
 #include "memory/gcLocker.inline.hpp"
 #include "memory/genCollectedHeap.hpp"
 #include "memory/generationSpec.hpp"
 #include "memory/space.hpp"
 #include "memory/universe.hpp"
 #include "runtime/arguments.hpp"
 #include "runtime/globals_extension.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/java.hpp"
 #include "runtime/thread.inline.hpp"
 #include "runtime/vmThread.hpp"
 #include "utilities/macros.hpp"
 #if INCLUDE_ALL_GCS
 #include "gc_implementation/concurrentMarkSweep/cmsAdaptiveSizePolicy.hpp"
 #include "gc_implementation/concurrentMarkSweep/cmsGCAdaptivePolicyCounters.hpp"
 #endif // INCLUDE_ALL_GCS
 // CollectorPolicy methods.
 CollectorPolicy::CollectorPolicy() :
     _space_alignment(0),
     _heap_alignment(0),
     _initial_heap_byte_size(InitialHeapSize),
     _max_heap_byte_size(MaxHeapSize),
     _min_heap_byte_size(Arguments::min_heap_size()),
     _max_heap_size_cmdline(false),
     _size_policy(NULL),
     _should_clear_all_soft_refs(false),
     _all_soft_refs_clear(false)
 {}
 #ifdef ASSERT
 void CollectorPolicy::assert_flags() {
   assert(InitialHeapSize <= MaxHeapSize, "Ergonomics decided on incompatible initial and maximum heap sizes");
   assert(InitialHeapSize % _heap_alignment == 0, "InitialHeapSize alignment");
   assert(MaxHeapSize % _heap_alignment == 0, "MaxHeapSize alignment");
 }
 void CollectorPolicy::assert_size_info() {
   assert(InitialHeapSize == _initial_heap_byte_size, "Discrepancy between InitialHeapSize flag and local storage");
   assert(MaxHeapSize == _max_heap_byte_size, "Discrepancy between MaxHeapSize flag and local storage");
   assert(_max_heap_byte_size >= _min_heap_byte_size, "Ergonomics decided on incompatible minimum and maximum heap sizes");
   assert(_initial_heap_byte_size >= _min_heap_byte_size, "Ergonomics decided on incompatible initial and minimum heap sizes");
   assert(_max_heap_byte_size >= _initial_heap_byte_size, "Ergonomics decided on incompatible initial and maximum heap sizes");
   assert(_min_heap_byte_size % _heap_alignment == 0, "min_heap_byte_size alignment");
   assert(_initial_heap_byte_size % _heap_alignment == 0, "initial_heap_byte_size alignment");
   assert(_max_heap_byte_size % _heap_alignment == 0, "max_heap_byte_size alignment");
 }
 #endif // ASSERT
 void CollectorPolicy::initialize_flags() {
   assert(_space_alignment != 0, "Space alignment not set up properly");
   assert(_heap_alignment != 0, "Heap alignment not set up properly");
   assert(_heap_alignment >= _space_alignment,
          err_msg("heap_alignment: " SIZE_FORMAT " less than space_alignment: " SIZE_FORMAT,
                  _heap_alignment, _space_alignment));
   assert(_heap_alignment % _space_alignment == 0,
          err_msg("heap_alignment: " SIZE_FORMAT " not aligned by space_alignment: " SIZE_FORMAT,
                  _heap_alignment, _space_alignment));
   if (FLAG_IS_CMDLINE(MaxHeapSize)) {
     if (FLAG_IS_CMDLINE(InitialHeapSize) && InitialHeapSize > MaxHeapSize) {
       vm_exit_during_initialization("Initial heap size set to a larger value than the maximum heap size");
     }
     if (_min_heap_byte_size != 0 && MaxHeapSize < _min_heap_byte_size) {
       vm_exit_during_initialization("Incompatible minimum and maximum heap sizes specified");
     }
     _max_heap_size_cmdline = true;
   }
   // Check heap parameter properties
   if (InitialHeapSize < M) {
     vm_exit_during_initialization("Too small initial heap");
   }
   if (_min_heap_byte_size < M) {
     vm_exit_during_initialization("Too small minimum heap");
   }
   // User inputs from -Xmx and -Xms must be aligned
   _min_heap_byte_size = align_size_up(_min_heap_byte_size, _heap_alignment);
   uintx aligned_initial_heap_size = align_size_up(InitialHeapSize, _heap_alignment);
   uintx aligned_max_heap_size = align_size_up(MaxHeapSize, _heap_alignment);
   // Write back to flags if the values changed
   if (aligned_initial_heap_size != InitialHeapSize) {
     FLAG_SET_ERGO(uintx, InitialHeapSize, aligned_initial_heap_size);
   }
   if (aligned_max_heap_size != MaxHeapSize) {
     FLAG_SET_ERGO(uintx, MaxHeapSize, aligned_max_heap_size);
   }
   if (FLAG_IS_CMDLINE(InitialHeapSize) && _min_heap_byte_size != 0 &&
       InitialHeapSize < _min_heap_byte_size) {
     vm_exit_during_initialization("Incompatible minimum and initial heap sizes specified");
   }
   if (!FLAG_IS_DEFAULT(InitialHeapSize) && InitialHeapSize > MaxHeapSize) {
     FLAG_SET_ERGO(uintx, MaxHeapSize, InitialHeapSize);
   } else if (!FLAG_IS_DEFAULT(MaxHeapSize) && InitialHeapSize > MaxHeapSize) {
     FLAG_SET_ERGO(uintx, InitialHeapSize, MaxHeapSize);
     if (InitialHeapSize < _min_heap_byte_size) {
       _min_heap_byte_size = InitialHeapSize;
     }
   }
   _initial_heap_byte_size = InitialHeapSize;
   _max_heap_byte_size = MaxHeapSize;
   FLAG_SET_ERGO(uintx, MinHeapDeltaBytes, align_size_up(MinHeapDeltaBytes, _space_alignment));
   DEBUG_ONLY(CollectorPolicy::assert_flags();)
 }
 void CollectorPolicy::initialize_size_info() {
   if (PrintGCDetails && Verbose) {
     gclog_or_tty->print_cr("Minimum heap " SIZE_FORMAT "  Initial heap "
       SIZE_FORMAT "  Maximum heap " SIZE_FORMAT,
       _min_heap_byte_size, _initial_heap_byte_size, _max_heap_byte_size);
   }
   DEBUG_ONLY(CollectorPolicy::assert_size_info();)
 }
 bool CollectorPolicy::use_should_clear_all_soft_refs(bool v) {
   bool result = _should_clear_all_soft_refs;
   set_should_clear_all_soft_refs(false);
   return result;
 }
 GenRemSet* CollectorPolicy::create_rem_set(MemRegion whole_heap,
                                            int max_covered_regions) {
   return new CardTableRS(whole_heap, max_covered_regions);
 }
 void CollectorPolicy::cleared_all_soft_refs() {
   // If near gc overhear limit, continue to clear SoftRefs.  SoftRefs may
   // have been cleared in the last collection but if the gc overhear
   // limit continues to be near, SoftRefs should still be cleared.
   if (size_policy() != NULL) {
     _should_clear_all_soft_refs = size_policy()->gc_overhead_limit_near();
   }
   _all_soft_refs_clear = true;
 }
 size_t CollectorPolicy::compute_heap_alignment() {
   // The card marking array and the offset arrays for old generations are
   // committed in os pages as well. Make sure they are entirely full (to
   // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1
   // byte entry and the os page size is 4096, the maximum heap size should
   // be 512*4096 = 2MB aligned.
   // There is only the GenRemSet in Hotspot and only the GenRemSet::CardTable
   // is supported.
   // Requirements of any new remembered set implementations must be added here.
   size_t alignment = GenRemSet::max_alignment_constraint(GenRemSet::CardTable);
   if (UseLargePages) {
       // In presence of large pages we have to make sure that our
       // alignment is large page aware.
       alignment = lcm(os::large_page_size(), alignment);
   }
   return alignment;
 }
 // GenCollectorPolicy methods.
 GenCollectorPolicy::GenCollectorPolicy() :
     _min_gen0_size(0),
     _initial_gen0_size(0),
     _max_gen0_size(0),
     _gen_alignment(0),
     _generations(NULL)
 {}
 size_t GenCollectorPolicy::scale_by_NewRatio_aligned(size_t base_size) {
   return align_size_down_bounded(base_size / (NewRatio + 1), _gen_alignment);
 }
 size_t GenCollectorPolicy::bound_minus_alignment(size_t desired_size,
                                                  size_t maximum_size) {
   size_t max_minus = maximum_size - _gen_alignment;
   return desired_size < max_minus ? desired_size : max_minus;
 }
 void GenCollectorPolicy::initialize_size_policy(size_t init_eden_size,
                                                 size_t init_promo_size,
                                                 size_t init_survivor_size) {
   const double max_gc_pause_sec = ((double) MaxGCPauseMillis) / 1000.0;
   _size_policy = new AdaptiveSizePolicy(init_eden_size,
                                         init_promo_size,
                                         init_survivor_size,
                                         max_gc_pause_sec,
                                         GCTimeRatio);
 }
 size_t GenCollectorPolicy::young_gen_size_lower_bound() {
   // The young generation must be aligned and have room for eden + two survivors
   return align_size_up(3 * _space_alignment, _gen_alignment);
 }
 #ifdef ASSERT
 void GenCollectorPolicy::assert_flags() {
   CollectorPolicy::assert_flags();
   assert(NewSize >= _min_gen0_size, "Ergonomics decided on a too small young gen size");
   assert(NewSize <= MaxNewSize, "Ergonomics decided on incompatible initial and maximum young gen sizes");
   assert(FLAG_IS_DEFAULT(MaxNewSize) || MaxNewSize < MaxHeapSize, "Ergonomics decided on incompatible maximum young gen and heap sizes");
   assert(NewSize % _gen_alignment == 0, "NewSize alignment");
   assert(FLAG_IS_DEFAULT(MaxNewSize) || MaxNewSize % _gen_alignment == 0, "MaxNewSize alignment");
 }
 void TwoGenerationCollectorPolicy::assert_flags() {
   GenCollectorPolicy::assert_flags();
   assert(OldSize + NewSize <= MaxHeapSize, "Ergonomics decided on incompatible generation and heap sizes");
   assert(OldSize % _gen_alignment == 0, "OldSize alignment");
 }
 void GenCollectorPolicy::assert_size_info() {
   CollectorPolicy::assert_size_info();
   // GenCollectorPolicy::initialize_size_info may update the MaxNewSize
   assert(MaxNewSize < MaxHeapSize, "Ergonomics decided on incompatible maximum young and heap sizes");
   assert(NewSize == _initial_gen0_size, "Discrepancy between NewSize flag and local storage");
   assert(MaxNewSize == _max_gen0_size, "Discrepancy between MaxNewSize flag and local storage");
   assert(_min_gen0_size <= _initial_gen0_size, "Ergonomics decided on incompatible minimum and initial young gen sizes");
   assert(_initial_gen0_size <= _max_gen0_size, "Ergonomics decided on incompatible initial and maximum young gen sizes");
   assert(_min_gen0_size % _gen_alignment == 0, "_min_gen0_size alignment");
   assert(_initial_gen0_size % _gen_alignment == 0, "_initial_gen0_size alignment");
   assert(_max_gen0_size % _gen_alignment == 0, "_max_gen0_size alignment");
 }
 void TwoGenerationCollectorPolicy::assert_size_info() {
   GenCollectorPolicy::assert_size_info();
   assert(OldSize == _initial_gen1_size, "Discrepancy between OldSize flag and local storage");
   assert(_min_gen1_size <= _initial_gen1_size, "Ergonomics decided on incompatible minimum and initial old gen sizes");
   assert(_initial_gen1_size <= _max_gen1_size, "Ergonomics decided on incompatible initial and maximum old gen sizes");
   assert(_max_gen1_size % _gen_alignment == 0, "_max_gen1_size alignment");
   assert(_initial_gen1_size % _gen_alignment == 0, "_initial_gen1_size alignment");
   assert(_max_heap_byte_size <= (_max_gen0_size + _max_gen1_size), "Total maximum heap sizes must be sum of generation maximum sizes");
 }
 #endif // ASSERT
 void GenCollectorPolicy::initialize_flags() {
   CollectorPolicy::initialize_flags();
   assert(_gen_alignment != 0, "Generation alignment not set up properly");
   assert(_heap_alignment >= _gen_alignment,
          err_msg("heap_alignment: " SIZE_FORMAT " less than gen_alignment: " SIZE_FORMAT,
                  _heap_alignment, _gen_alignment));
   assert(_gen_alignment % _space_alignment == 0,
          err_msg("gen_alignment: " SIZE_FORMAT " not aligned by space_alignment: " SIZE_FORMAT,
                  _gen_alignment, _space_alignment));
   assert(_heap_alignment % _gen_alignment == 0,
          err_msg("heap_alignment: " SIZE_FORMAT " not aligned by gen_alignment: " SIZE_FORMAT,
                  _heap_alignment, _gen_alignment));
   // All generational heaps have a youngest gen; handle those flags here
   // Make sure the heap is large enough for two generations
   uintx smallest_new_size = young_gen_size_lower_bound();
   uintx smallest_heap_size = align_size_up(smallest_new_size + align_size_up(_space_alignment, _gen_alignment),
                                            _heap_alignment);
   if (MaxHeapSize < smallest_heap_size) {
     FLAG_SET_ERGO(uintx, MaxHeapSize, smallest_heap_size);
     _max_heap_byte_size = MaxHeapSize;
   }
   // If needed, synchronize _min_heap_byte size and _initial_heap_byte_size
   if (_min_heap_byte_size < smallest_heap_size) {
     _min_heap_byte_size = smallest_heap_size;
     if (InitialHeapSize < _min_heap_byte_size) {
       FLAG_SET_ERGO(uintx, InitialHeapSize, smallest_heap_size);
       _initial_heap_byte_size = smallest_heap_size;
     }
   }
   // Now take the actual NewSize into account. We will silently increase NewSize
   // if the user specified a smaller or unaligned value.
   smallest_new_size = MAX2(smallest_new_size, (uintx)align_size_down(NewSize, _gen_alignment));
   if (smallest_new_size != NewSize) {
     // Do not use FLAG_SET_ERGO to update NewSize here, since this will override
     // if NewSize was set on the command line or not. This information is needed
     // later when setting the initial and minimum young generation size.
     NewSize = smallest_new_size;
   }
   _initial_gen0_size = NewSize;
   if (!FLAG_IS_DEFAULT(MaxNewSize)) {
     uintx min_new_size = MAX2(_gen_alignment, _min_gen0_size);
     if (MaxNewSize >= MaxHeapSize) {
       // Make sure there is room for an old generation
       uintx smaller_max_new_size = MaxHeapSize - _gen_alignment;
       if (FLAG_IS_CMDLINE(MaxNewSize)) {
         warning("MaxNewSize (" SIZE_FORMAT "k) is equal to or greater than the entire "
                 "heap (" SIZE_FORMAT "k).  A new max generation size of " SIZE_FORMAT "k will be used.",
                 MaxNewSize/K, MaxHeapSize/K, smaller_max_new_size/K);
       }
       FLAG_SET_ERGO(uintx, MaxNewSize, smaller_max_new_size);
       if (NewSize > MaxNewSize) {
         FLAG_SET_ERGO(uintx, NewSize, MaxNewSize);
         _initial_gen0_size = NewSize;
       }
     } else if (MaxNewSize < min_new_size) {
       FLAG_SET_ERGO(uintx, MaxNewSize, min_new_size);
     } else if (!is_size_aligned(MaxNewSize, _gen_alignment)) {
       FLAG_SET_ERGO(uintx, MaxNewSize, align_size_down(MaxNewSize, _gen_alignment));
     }
     _max_gen0_size = MaxNewSize;
   }
   if (NewSize > MaxNewSize) {
     // At this point this should only happen if the user specifies a large NewSize and/or
     // a small (but not too small) MaxNewSize.
     if (FLAG_IS_CMDLINE(MaxNewSize)) {
       warning("NewSize (" SIZE_FORMAT "k) is greater than the MaxNewSize (" SIZE_FORMAT "k). "
               "A new max generation size of " SIZE_FORMAT "k will be used.",
               NewSize/K, MaxNewSize/K, NewSize/K);
     }
     FLAG_SET_ERGO(uintx, MaxNewSize, NewSize);
     _max_gen0_size = MaxNewSize;
   }
   if (SurvivorRatio < 1 || NewRatio < 1) {
     vm_exit_during_initialization("Invalid young gen ratio specified");
   }
   DEBUG_ONLY(GenCollectorPolicy::assert_flags();)
 }
 void TwoGenerationCollectorPolicy::initialize_flags() {
   GenCollectorPolicy::initialize_flags();
   if (!is_size_aligned(OldSize, _gen_alignment)) {
     FLAG_SET_ERGO(uintx, OldSize, align_size_down(OldSize, _gen_alignment));
   }
   if (FLAG_IS_CMDLINE(OldSize) && FLAG_IS_DEFAULT(MaxHeapSize)) {
     // NewRatio will be used later to set the young generation size so we use
     // it to calculate how big the heap should be based on the requested OldSize
     // and NewRatio.
     assert(NewRatio > 0, "NewRatio should have been set up earlier");
     size_t calculated_heapsize = (OldSize / NewRatio) * (NewRatio + 1);
     calculated_heapsize = align_size_up(calculated_heapsize, _heap_alignment);
     FLAG_SET_ERGO(uintx, MaxHeapSize, calculated_heapsize);
     _max_heap_byte_size = MaxHeapSize;
     FLAG_SET_ERGO(uintx, InitialHeapSize, calculated_heapsize);
     _initial_heap_byte_size = InitialHeapSize;
   }
   // adjust max heap size if necessary
   if (NewSize + OldSize > MaxHeapSize) {
     if (_max_heap_size_cmdline) {
       // somebody set a maximum heap size with the intention that we should not
       // exceed it. Adjust New/OldSize as necessary.
       uintx calculated_size = NewSize + OldSize;
       double shrink_factor = (double) MaxHeapSize / calculated_size;
       uintx smaller_new_size = align_size_down((uintx)(NewSize * shrink_factor), _gen_alignment);
       FLAG_SET_ERGO(uintx, NewSize, MAX2(young_gen_size_lower_bound(), smaller_new_size));
       _initial_gen0_size = NewSize;
       // OldSize is already aligned because above we aligned MaxHeapSize to
       // _heap_alignment, and we just made sure that NewSize is aligned to
       // _gen_alignment. In initialize_flags() we verified that _heap_alignment
       // is a multiple of _gen_alignment.
       FLAG_SET_ERGO(uintx, OldSize, MaxHeapSize - NewSize);
     } else {
       FLAG_SET_ERGO(uintx, MaxHeapSize, align_size_up(NewSize + OldSize, _heap_alignment));
       _max_heap_byte_size = MaxHeapSize;
     }
   }
   always_do_update_barrier = UseConcMarkSweepGC;
   DEBUG_ONLY(TwoGenerationCollectorPolicy::assert_flags();)
 }
 // Values set on the command line win over any ergonomically
 // set command line parameters.
 // Ergonomic choice of parameters are done before this
 // method is called.  Values for command line parameters such as NewSize
 // and MaxNewSize feed those ergonomic choices into this method.
 // This method makes the final generation sizings consistent with
 // themselves and with overall heap sizings.
 // In the absence of explicitly set command line flags, policies
 // such as the use of NewRatio are used to size the generation.
 void GenCollectorPolicy::initialize_size_info() {
   CollectorPolicy::initialize_size_info();
   // _space_alignment is used for alignment within a generation.
   // There is additional alignment done down stream for some
   // collectors that sometimes causes unwanted rounding up of
   // generations sizes.
   // Determine maximum size of gen0
   size_t max_new_size = 0;
   if (!FLAG_IS_DEFAULT(MaxNewSize)) {
     max_new_size = MaxNewSize;
   } else {
     max_new_size = scale_by_NewRatio_aligned(_max_heap_byte_size);
     // Bound the maximum size by NewSize below (since it historically
     // would have been NewSize and because the NewRatio calculation could
     // yield a size that is too small) and bound it by MaxNewSize above.
     // Ergonomics plays here by previously calculating the desired
     // NewSize and MaxNewSize.
     max_new_size = MIN2(MAX2(max_new_size, NewSize), MaxNewSize);
   }
   assert(max_new_size > 0, "All paths should set max_new_size");
   // Given the maximum gen0 size, determine the initial and
   // minimum gen0 sizes.
   if (_max_heap_byte_size == _min_heap_byte_size) {
     // The maximum and minimum heap sizes are the same so
     // the generations minimum and initial must be the
     // same as its maximum.
     _min_gen0_size = max_new_size;
     _initial_gen0_size = max_new_size;
     _max_gen0_size = max_new_size;
   } else {
     size_t desired_new_size = 0;
     if (FLAG_IS_CMDLINE(NewSize)) {
       // If NewSize is set on the command line, we must use it as
       // the initial size and it also makes sense to use it as the
       // lower limit.
       _min_gen0_size = NewSize;
       desired_new_size = NewSize;
       max_new_size = MAX2(max_new_size, NewSize);
     } else if (FLAG_IS_ERGO(NewSize)) {
       // If NewSize is set ergonomically, we should use it as a lower
       // limit, but use NewRatio to calculate the initial size.
       _min_gen0_size = NewSize;
       desired_new_size =
         MAX2(scale_by_NewRatio_aligned(_initial_heap_byte_size), NewSize);
       max_new_size = MAX2(max_new_size, NewSize);
     } else {
       // For the case where NewSize is the default, use NewRatio
       // to size the minimum and initial generation sizes.
       // Use the default NewSize as the floor for these values.  If
       // NewRatio is overly large, the resulting sizes can be too
       // small.
       _min_gen0_size = MAX2(scale_by_NewRatio_aligned(_min_heap_byte_size), NewSize);
       desired_new_size =
         MAX2(scale_by_NewRatio_aligned(_initial_heap_byte_size), NewSize);
     }
     assert(_min_gen0_size > 0, "Sanity check");
     _initial_gen0_size = desired_new_size;
     _max_gen0_size = max_new_size;
     // At this point the desirable initial and minimum sizes have been
     // determined without regard to the maximum sizes.
     // Bound the sizes by the corresponding overall heap sizes.
     _min_gen0_size = bound_minus_alignment(_min_gen0_size, _min_heap_byte_size);
     _initial_gen0_size = bound_minus_alignment(_initial_gen0_size, _initial_heap_byte_size);
     _max_gen0_size = bound_minus_alignment(_max_gen0_size, _max_heap_byte_size);
     // At this point all three sizes have been checked against the
     // maximum sizes but have not been checked for consistency
     // among the three.
     // Final check min <= initial <= max
     _min_gen0_size = MIN2(_min_gen0_size, _max_gen0_size);
     _initial_gen0_size = MAX2(MIN2(_initial_gen0_size, _max_gen0_size), _min_gen0_size);
     _min_gen0_size = MIN2(_min_gen0_size, _initial_gen0_size);
   }
   // Write back to flags if necessary
   if (NewSize != _initial_gen0_size) {
     FLAG_SET_ERGO(uintx, NewSize, _initial_gen0_size);
   }
   if (MaxNewSize != _max_gen0_size) {
     FLAG_SET_ERGO(uintx, MaxNewSize, _max_gen0_size);
   }
   if (PrintGCDetails && Verbose) {
     gclog_or_tty->print_cr("1: Minimum gen0 " SIZE_FORMAT "  Initial gen0 "
       SIZE_FORMAT "  Maximum gen0 " SIZE_FORMAT,
       _min_gen0_size, _initial_gen0_size, _max_gen0_size);
   }
   DEBUG_ONLY(GenCollectorPolicy::assert_size_info();)
 }
 // Call this method during the sizing of the gen1 to make
 // adjustments to gen0 because of gen1 sizing policy.  gen0 initially has
 // the most freedom in sizing because it is done before the
 // policy for gen1 is applied.  Once gen1 policies have been applied,
 // there may be conflicts in the shape of the heap and this method
 // is used to make the needed adjustments.  The application of the
 // policies could be more sophisticated (iterative for example) but
 // keeping it simple also seems a worthwhile goal.
 bool TwoGenerationCollectorPolicy::adjust_gen0_sizes(size_t* gen0_size_ptr,
                                                      size_t* gen1_size_ptr,
                                                      const size_t heap_size) {
   bool result = false;
   if ((*gen0_size_ptr + *gen1_size_ptr) > heap_size) {
     uintx smallest_new_size = young_gen_size_lower_bound();
     if ((heap_size < (*gen0_size_ptr + _min_gen1_size)) &&
         (heap_size >= _min_gen1_size + smallest_new_size)) {
       // Adjust gen0 down to accommodate _min_gen1_size
       *gen0_size_ptr = align_size_down_bounded(heap_size - _min_gen1_size, _gen_alignment);
       result = true;
     } else {
       *gen1_size_ptr = align_size_down_bounded(heap_size - *gen0_size_ptr, _gen_alignment);
     }
   }
   return result;
 }
 // Minimum sizes of the generations may be different than
 // the initial sizes.  An inconsistently is permitted here
 // in the total size that can be specified explicitly by
 // command line specification of OldSize and NewSize and
 // also a command line specification of -Xms.  Issue a warning
 // but allow the values to pass.
 void TwoGenerationCollectorPolicy::initialize_size_info() {
   GenCollectorPolicy::initialize_size_info();
   // At this point the minimum, initial and maximum sizes
   // of the overall heap and of gen0 have been determined.
   // The maximum gen1 size can be determined from the maximum gen0
   // and maximum heap size since no explicit flags exits
   // for setting the gen1 maximum.
   _max_gen1_size = MAX2(_max_heap_byte_size - _max_gen0_size, _gen_alignment);
   // If no explicit command line flag has been set for the
   // gen1 size, use what is left for gen1.
   if (!FLAG_IS_CMDLINE(OldSize)) {
     // The user has not specified any value but the ergonomics
     // may have chosen a value (which may or may not be consistent
     // with the overall heap size).  In either case make
     // the minimum, maximum and initial sizes consistent
     // with the gen0 sizes and the overall heap sizes.
     _min_gen1_size = MAX2(_min_heap_byte_size - _min_gen0_size, _gen_alignment);
     _initial_gen1_size = MAX2(_initial_heap_byte_size - _initial_gen0_size, _gen_alignment);
     // _max_gen1_size has already been made consistent above
     FLAG_SET_ERGO(uintx, OldSize, _initial_gen1_size);
   } else {
     // It's been explicitly set on the command line.  Use the
     // OldSize and then determine the consequences.
     _min_gen1_size = MIN2(OldSize, _min_heap_byte_size - _min_gen0_size);
     _initial_gen1_size = OldSize;
     // If the user has explicitly set an OldSize that is inconsistent
     // with other command line flags, issue a warning.
     // The generation minimums and the overall heap mimimum should
     // be within one generation alignment.
     if ((_min_gen1_size + _min_gen0_size + _gen_alignment) < _min_heap_byte_size) {
       warning("Inconsistency between minimum heap size and minimum "
               "generation sizes: using minimum heap = " SIZE_FORMAT,
               _min_heap_byte_size);
     }
     if (OldSize > _max_gen1_size) {
       warning("Inconsistency between maximum heap size and maximum "
               "generation sizes: using maximum heap = " SIZE_FORMAT
               " -XX:OldSize flag is being ignored",
               _max_heap_byte_size);
     }
     // If there is an inconsistency between the OldSize and the minimum and/or
     // initial size of gen0, since OldSize was explicitly set, OldSize wins.
     if (adjust_gen0_sizes(&_min_gen0_size, &_min_gen1_size, _min_heap_byte_size)) {
       if (PrintGCDetails && Verbose) {
         gclog_or_tty->print_cr("2: Minimum gen0 " SIZE_FORMAT "  Initial gen0 "
               SIZE_FORMAT "  Maximum gen0 " SIZE_FORMAT,
               _min_gen0_size, _initial_gen0_size, _max_gen0_size);
       }
     }
     // Initial size
     if (adjust_gen0_sizes(&_initial_gen0_size, &_initial_gen1_size,
                           _initial_heap_byte_size)) {
       if (PrintGCDetails && Verbose) {
         gclog_or_tty->print_cr("3: Minimum gen0 " SIZE_FORMAT "  Initial gen0 "
           SIZE_FORMAT "  Maximum gen0 " SIZE_FORMAT,
           _min_gen0_size, _initial_gen0_size, _max_gen0_size);
       }
     }
   }
   // Enforce the maximum gen1 size.
   _min_gen1_size = MIN2(_min_gen1_size, _max_gen1_size);
   // Check that min gen1 <= initial gen1 <= max gen1
   _initial_gen1_size = MAX2(_initial_gen1_size, _min_gen1_size);
   _initial_gen1_size = MIN2(_initial_gen1_size, _max_gen1_size);
   // Write back to flags if necessary
   if (NewSize != _initial_gen0_size) {
     FLAG_SET_ERGO(uintx, NewSize, _initial_gen0_size);
   }
   if (MaxNewSize != _max_gen0_size) {
     FLAG_SET_ERGO(uintx, MaxNewSize, _max_gen0_size);
   }
   if (OldSize != _initial_gen1_size) {
     FLAG_SET_ERGO(uintx, OldSize, _initial_gen1_size);
   }
   if (PrintGCDetails && Verbose) {
     gclog_or_tty->print_cr("Minimum gen1 " SIZE_FORMAT "  Initial gen1 "
       SIZE_FORMAT "  Maximum gen1 " SIZE_FORMAT,
       _min_gen1_size, _initial_gen1_size, _max_gen1_size);
   }
   DEBUG_ONLY(TwoGenerationCollectorPolicy::assert_size_info();)
 }
 HeapWord* GenCollectorPolicy::mem_allocate_work(size_t size,
                                         bool is_tlab,
                                         bool* gc_overhead_limit_was_exceeded) {
   GenCollectedHeap *gch = GenCollectedHeap::heap();
   debug_only(gch->check_for_valid_allocation_state());
   assert(gch->no_gc_in_progress(), "Allocation during gc not allowed");
   // In general gc_overhead_limit_was_exceeded should be false so
   // set it so here and reset it to true only if the gc time
   // limit is being exceeded as checked below.
   *gc_overhead_limit_was_exceeded = false;
   HeapWord* result = NULL;
   // Loop until the allocation is satisified,
   // or unsatisfied after GC.
   for (uint try_count = 1, gclocker_stalled_count = 0; /* return or throw */; try_count += 1) {
     HandleMark hm; // discard any handles allocated in each iteration
     // First allocation attempt is lock-free.
     Generation *gen0 = gch->get_gen(0);
     assert(gen0->supports_inline_contig_alloc(),
       "Otherwise, must do alloc within heap lock");
     if (gen0->should_allocate(size, is_tlab)) {
       result = gen0->par_allocate(size, is_tlab);
       if (result != NULL) {
         assert(gch->is_in_reserved(result), "result not in heap");
         return result;
       }
     }
     uint gc_count_before;  // read inside the Heap_lock locked region
     {
       MutexLocker ml(Heap_lock);
       if (PrintGC && Verbose) {
         gclog_or_tty->print_cr("TwoGenerationCollectorPolicy::mem_allocate_work:"
                       " attempting locked slow path allocation");
       }
       // Note that only large objects get a shot at being
       // allocated in later generations.
       bool first_only = ! should_try_older_generation_allocation(size);
       result = gch->attempt_allocation(size, is_tlab, first_only);
       if (result != NULL) {
         assert(gch->is_in_reserved(result), "result not in heap");
         return result;
       }
       if (GC_locker::is_active_and_needs_gc()) {
         if (is_tlab) {
           return NULL;  // Caller will retry allocating individual object
         }
         if (!gch->is_maximal_no_gc()) {
           // Try and expand heap to satisfy request
           result = expand_heap_and_allocate(size, is_tlab);
           // result could be null if we are out of space
           if (result != NULL) {
             return result;
           }
         }
         if (gclocker_stalled_count > GCLockerRetryAllocationCount) {
           return NULL; // we didn't get to do a GC and we didn't get any memory
         }
         // If this thread is not in a jni critical section, we stall
         // the requestor until the critical section has cleared and
         // GC allowed. When the critical section clears, a GC is
         // initiated by the last thread exiting the critical section; so
         // we retry the allocation sequence from the beginning of the loop,
         // rather than causing more, now probably unnecessary, GC attempts.
         JavaThread* jthr = JavaThread::current();
         if (!jthr->in_critical()) {
           MutexUnlocker mul(Heap_lock);
           // Wait for JNI critical section to be exited
           GC_locker::stall_until_clear();
           gclocker_stalled_count += 1;
           continue;
         } else {
           if (CheckJNICalls) {
             fatal("Possible deadlock due to allocating while"
                   " in jni critical section");
           }
           return NULL;
         }
       }
       // Read the gc count while the heap lock is held.
       gc_count_before = Universe::heap()->total_collections();
     }
     VM_GenCollectForAllocation op(size, is_tlab, gc_count_before);
     VMThread::execute(&op);
     if (op.prologue_succeeded()) {
       result = op.result();
       if (op.gc_locked()) {
          assert(result == NULL, "must be NULL if gc_locked() is true");
          continue;  // retry and/or stall as necessary
       }
       // Allocation has failed and a collection
       // has been done.  If the gc time limit was exceeded the
       // this time, return NULL so that an out-of-memory
       // will be thrown.  Clear gc_overhead_limit_exceeded
       // so that the overhead exceeded does not persist.
       const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded();
       const bool softrefs_clear = all_soft_refs_clear();
       if (limit_exceeded && softrefs_clear) {
         *gc_overhead_limit_was_exceeded = true;
         size_policy()->set_gc_overhead_limit_exceeded(false);
         if (op.result() != NULL) {
           CollectedHeap::fill_with_object(op.result(), size);
         }
         return NULL;
       }
       assert(result == NULL || gch->is_in_reserved(result),
              "result not in heap");
       return result;
     }
     // Give a warning if we seem to be looping forever.
     if ((QueuedAllocationWarningCount > 0) &&
         (try_count % QueuedAllocationWarningCount == 0)) {
           warning("TwoGenerationCollectorPolicy::mem_allocate_work retries %d times \n\t"
                   " size=" SIZE_FORMAT " %s", try_count, size, is_tlab ? "(TLAB)" : "");
     }
   }
 }
 HeapWord* GenCollectorPolicy::expand_heap_and_allocate(size_t size,
                                                        bool   is_tlab) {
   GenCollectedHeap *gch = GenCollectedHeap::heap();
   HeapWord* result = NULL;
   for (int i = number_of_generations() - 1; i >= 0 && result == NULL; i--) {
     Generation *gen = gch->get_gen(i);
     if (gen->should_allocate(size, is_tlab)) {
       result = gen->expand_and_allocate(size, is_tlab);
     }
   }
   assert(result == NULL || gch->is_in_reserved(result), "result not in heap");
   return result;
 }
 HeapWord* GenCollectorPolicy::satisfy_failed_allocation(size_t size,
                                                         bool   is_tlab) {
   GenCollectedHeap *gch = GenCollectedHeap::heap();
   GCCauseSetter x(gch, GCCause::_allocation_failure);
   HeapWord* result = NULL;
   assert(size != 0, "Precondition violated");
   if (GC_locker::is_active_and_needs_gc()) {
     // GC locker is active; instead of a collection we will attempt
     // to expand the heap, if there's room for expansion.
     if (!gch->is_maximal_no_gc()) {
       result = expand_heap_and_allocate(size, is_tlab);
     }
     return result;   // could be null if we are out of space
   } else if (!gch->incremental_collection_will_fail(false /* don't consult_young */)) {
     // Do an incremental collection.
     gch->do_collection(false            /* full */,
                        false            /* clear_all_soft_refs */,
                        size             /* size */,
                        is_tlab          /* is_tlab */,
                        number_of_generations() - 1 /* max_level */);
   } else {
     if (Verbose && PrintGCDetails) {
       gclog_or_tty->print(" :: Trying full because partial may fail :: ");
     }
     // Try a full collection; see delta for bug id 6266275
     // for the original code and why this has been simplified
     // with from-space allocation criteria modified and
     // such allocation moved out of the safepoint path.
     gch->do_collection(true             /* full */,
                        false            /* clear_all_soft_refs */,
                        size             /* size */,
                        is_tlab          /* is_tlab */,
                        number_of_generations() - 1 /* max_level */);
   }
   result = gch->attempt_allocation(size, is_tlab, false /*first_only*/);
   if (result != NULL) {
     assert(gch->is_in_reserved(result), "result not in heap");
     return result;
   }
   // OK, collection failed, try expansion.
   result = expand_heap_and_allocate(size, is_tlab);
   if (result != NULL) {
     return result;
   }
   // If we reach this point, we're really out of memory. Try every trick
   // we can to reclaim memory. Force collection of soft references. Force
   // a complete compaction of the heap. Any additional methods for finding
   // free memory should be here, especially if they are expensive. If this
   // attempt fails, an OOM exception will be thrown.
   {
     UIntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted
     gch->do_collection(true             /* full */,
                        true             /* clear_all_soft_refs */,
                        size             /* size */,
                        is_tlab          /* is_tlab */,
                        number_of_generations() - 1 /* max_level */);
   }
   result = gch->attempt_allocation(size, is_tlab, false /* first_only */);
   if (result != NULL) {
     assert(gch->is_in_reserved(result), "result not in heap");
     return result;
   }
   assert(!should_clear_all_soft_refs(),
     "Flag should have been handled and cleared prior to this point");
   // What else?  We might try synchronous finalization later.  If the total
   // space available is large enough for the allocation, then a more
   // complete compaction phase than we've tried so far might be
   // appropriate.
   return NULL;
 }
 MetaWord* CollectorPolicy::satisfy_failed_metadata_allocation(
                                                  ClassLoaderData* loader_data,
                                                  size_t word_size,
                                                  Metaspace::MetadataType mdtype) {
   uint loop_count = 0;
   uint gc_count = 0;
   uint full_gc_count = 0;
   assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");
   do {
     MetaWord* result = NULL;
     if (GC_locker::is_active_and_needs_gc()) {
       // If the GC_locker is active, just expand and allocate.
       // If that does not succeed, wait if this thread is not
       // in a critical section itself.
       result =
         loader_data->metaspace_non_null()->expand_and_allocate(word_size,
                                                                mdtype);
       if (result != NULL) {
         return result;
       }
       JavaThread* jthr = JavaThread::current();
       if (!jthr->in_critical()) {
         // Wait for JNI critical section to be exited
         GC_locker::stall_until_clear();
         // The GC invoked by the last thread leaving the critical
         // section will be a young collection and a full collection
         // is (currently) needed for unloading classes so continue
         // to the next iteration to get a full GC.
         continue;
       } else {
         if (CheckJNICalls) {
           fatal("Possible deadlock due to allocating while"
                 " in jni critical section");
         }
         return NULL;
       }
     }
     {  // Need lock to get self consistent gc_count's
       MutexLocker ml(Heap_lock);
       gc_count      = Universe::heap()->total_collections();
       full_gc_count = Universe::heap()->total_full_collections();
     }
     // Generate a VM operation
     VM_CollectForMetadataAllocation op(loader_data,
                                        word_size,
                                        mdtype,
                                        gc_count,
                                        full_gc_count,
                                        GCCause::_metadata_GC_threshold);
     VMThread::execute(&op);
     // If GC was locked out, try again.  Check
     // before checking success because the prologue
     // could have succeeded and the GC still have
     // been locked out.
     if (op.gc_locked()) {
       continue;
     }
     if (op.prologue_succeeded()) {
       return op.result();
     }
     loop_count++;
     if ((QueuedAllocationWarningCount > 0) &&
         (loop_count % QueuedAllocationWarningCount == 0)) {
       warning("satisfy_failed_metadata_allocation() retries %d times \n\t"
               " size=" SIZE_FORMAT, loop_count, word_size);
     }
   } while (true);  // Until a GC is done
 }
 // Return true if any of the following is true:
 // . the allocation won't fit into the current young gen heap
 // . gc locker is occupied (jni critical section)
 // . heap memory is tight -- the most recent previous collection
 //   was a full collection because a partial collection (would
 //   have) failed and is likely to fail again
 bool GenCollectorPolicy::should_try_older_generation_allocation(
         size_t word_size) const {
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   size_t gen0_capacity = gch->get_gen(0)->capacity_before_gc();
   return    (word_size > heap_word_size(gen0_capacity))
          || GC_locker::is_active_and_needs_gc()
          || gch->incremental_collection_failed();
 }
 //
 // MarkSweepPolicy methods
 //
 void MarkSweepPolicy::initialize_alignments() {
   _space_alignment = _gen_alignment = (uintx)Generation::GenGrain;
   _heap_alignment = compute_heap_alignment();
 }
 void MarkSweepPolicy::initialize_generations() {
   _generations = NEW_C_HEAP_ARRAY3(GenerationSpecPtr, number_of_generations(), mtGC, CURRENT_PC,
     AllocFailStrategy::RETURN_NULL);
   if (_generations == NULL) {
     vm_exit_during_initialization("Unable to allocate gen spec");
   }
   if (UseParNewGC) {
     _generations[0] = new GenerationSpec(Generation::ParNew, _initial_gen0_size, _max_gen0_size);
   } else {
     _generations[0] = new GenerationSpec(Generation::DefNew, _initial_gen0_size, _max_gen0_size);
   }
   _generations[1] = new GenerationSpec(Generation::MarkSweepCompact, _initial_gen1_size, _max_gen1_size);
   if (_generations[0] == NULL || _generations[1] == NULL) {
     vm_exit_during_initialization("Unable to allocate gen spec");
   }
 }
 void MarkSweepPolicy::initialize_gc_policy_counters() {
   // initialize the policy counters - 2 collectors, 3 generations
   if (UseParNewGC) {
     _gc_policy_counters = new GCPolicyCounters("ParNew:MSC", 2, 3);
   } else {
     _gc_policy_counters = new GCPolicyCounters("Copy:MSC", 2, 3);
   }
 }
 /////////////// Unit tests ///////////////
 #ifndef PRODUCT
 // Testing that the NewSize flag is handled correct is hard because it
 // depends on so many other configurable variables. This test only tries to
 // verify that there are some basic rules for NewSize honored by the policies.
 class TestGenCollectorPolicy {
 public:
   static void test() {
     size_t flag_value;
     save_flags();
     // Set some limits that makes the math simple.
     FLAG_SET_ERGO(uintx, MaxHeapSize, 180 * M);
     FLAG_SET_ERGO(uintx, InitialHeapSize, 120 * M);
     Arguments::set_min_heap_size(40 * M);
     // If NewSize is set on the command line, it should be used
     // for both min and initial young size if less than min heap.
     flag_value = 20 * M;
     FLAG_SET_CMDLINE(uintx, NewSize, flag_value);
     verify_min(flag_value);
     verify_initial(flag_value);
     // If NewSize is set on command line, but is larger than the min
     // heap size, it should only be used for initial young size.
     flag_value = 80 * M;
     FLAG_SET_CMDLINE(uintx, NewSize, flag_value);
     verify_initial(flag_value);
     // If NewSize has been ergonomically set, the collector policy
     // should use it for min but calculate the initial young size
     // using NewRatio.
     flag_value = 20 * M;
     FLAG_SET_ERGO(uintx, NewSize, flag_value);
     verify_min(flag_value);
     verify_scaled_initial(InitialHeapSize);
     restore_flags();
   }
   static void verify_min(size_t expected) {
     MarkSweepPolicy msp;
     msp.initialize_all();
     assert(msp.min_gen0_size() <= expected, err_msg("%zu  > %zu", msp.min_gen0_size(), expected));
   }
   static void verify_initial(size_t expected) {
     MarkSweepPolicy msp;
     msp.initialize_all();
     assert(msp.initial_gen0_size() == expected, err_msg("%zu != %zu", msp.initial_gen0_size(), expected));
   }
   static void verify_scaled_initial(size_t initial_heap_size) {
     MarkSweepPolicy msp;
     msp.initialize_all();
     size_t expected = msp.scale_by_NewRatio_aligned(initial_heap_size);
     assert(msp.initial_gen0_size() == expected, err_msg("%zu != %zu", msp.initial_gen0_size(), expected));
     assert(FLAG_IS_ERGO(NewSize) && NewSize == expected,
         err_msg("NewSize should have been set ergonomically to %zu, but was %zu", expected, NewSize));
   }
 private:
   static size_t original_InitialHeapSize;
   static size_t original_MaxHeapSize;
   static size_t original_MaxNewSize;
   static size_t original_MinHeapDeltaBytes;
   static size_t original_NewSize;
   static size_t original_OldSize;
   static void save_flags() {
     original_InitialHeapSize   = InitialHeapSize;
     original_MaxHeapSize       = MaxHeapSize;
     original_MaxNewSize        = MaxNewSize;
     original_MinHeapDeltaBytes = MinHeapDeltaBytes;
     original_NewSize           = NewSize;
     original_OldSize           = OldSize;
   }
   static void restore_flags() {
     InitialHeapSize   = original_InitialHeapSize;
     MaxHeapSize       = original_MaxHeapSize;
     MaxNewSize        = original_MaxNewSize;
     MinHeapDeltaBytes = original_MinHeapDeltaBytes;
     NewSize           = original_NewSize;
     OldSize           = original_OldSize;
   }
 };
 size_t TestGenCollectorPolicy::original_InitialHeapSize   = 0;
 size_t TestGenCollectorPolicy::original_MaxHeapSize       = 0;
 size_t TestGenCollectorPolicy::original_MaxNewSize        = 0;
 size_t TestGenCollectorPolicy::original_MinHeapDeltaBytes = 0;
 size_t TestGenCollectorPolicy::original_NewSize           = 0;
 size_t TestGenCollectorPolicy::original_OldSize           = 0;
 void TestNewSize_test() {
   TestGenCollectorPolicy::test();
 }
 #endif

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/memory/collectorPolicy.cpp@04ff2f6cd0eb (annotated)

src/share/vm/memory/collectorPolicy.cpp