/*

 * Copyright (c) 2001, 2013, 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);

  // Parallel GC does its own alignment of the generations to avoid requiring a

  // large page (256M on some platforms) for the permanent generation.  The

  // other collectors should also be updated to do their own alignment and then

  // this use of lcm() should be removed.

  if (UseLargePages && !UseParallelGC) {

      // 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 value.

  smallest_new_size = MAX2(smallest_new_size, (uintx)align_size_down(NewSize, _gen_alignment));

  if (smallest_new_size != NewSize) {

    FLAG_SET_ERGO(uintx, 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_DEFAULT(NewSize)) {

      // If NewSize is set ergonomically (for example by cms), it

      // would make sense to use it.  If it is used, also use it

      // to set the initial size.  Although there is no reason

      // the minimum size and the initial size have to be the same,

      // the current implementation gets into trouble during the calculation

      // of the tenured generation sizes if they are different.

      // Note that this makes the initial size and the minimum size

      // generally small compared to the NewRatio calculation.

      _min_gen0_size = NewSize;

      desired_new_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);