/*

 * 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

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 */

#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.

void CollectorPolicy::initialize_flags() {

  assert(max_alignment() >= min_alignment(),

      err_msg("max_alignment: " SIZE_FORMAT " less than min_alignment: " SIZE_FORMAT,

          max_alignment(), min_alignment()));

  assert(max_alignment() % min_alignment() == 0,

      err_msg("max_alignment: " SIZE_FORMAT " not aligned by min_alignment: " SIZE_FORMAT,

          max_alignment(), min_alignment()));

  if (MetaspaceSize > MaxMetaspaceSize) {

    MaxMetaspaceSize = MetaspaceSize;

  }

  MetaspaceSize = MAX2(min_alignment(), align_size_down_(MetaspaceSize, min_alignment()));

  // Don't increase Metaspace size limit above specified.

  MaxMetaspaceSize = align_size_down(MaxMetaspaceSize, max_alignment());

  if (MetaspaceSize > MaxMetaspaceSize) {

    MetaspaceSize = MaxMetaspaceSize;

  }

  MinMetaspaceExpansion = MAX2(min_alignment(), align_size_down_(MinMetaspaceExpansion, min_alignment()));

  MaxMetaspaceExpansion = MAX2(min_alignment(), align_size_down_(MaxMetaspaceExpansion, min_alignment()));

  MinHeapDeltaBytes = align_size_up(MinHeapDeltaBytes, min_alignment());

  assert(MetaspaceSize    % min_alignment() == 0, "metapace alignment");

  assert(MaxMetaspaceSize % max_alignment() == 0, "maximum metaspace alignment");

  if (MetaspaceSize < 256*K) {

    vm_exit_during_initialization("Too small initial Metaspace size");

  }

}

void CollectorPolicy::initialize_size_info() {

  set_max_heap_byte_size(align_size_up(MaxHeapSize, max_alignment()));

  // Check heap parameter properties

  if (initial_heap_byte_size() < M) {

    vm_exit_during_initialization("Too small initial heap");

  }

  // Check heap parameter properties

  if (min_heap_byte_size() < M) {

    vm_exit_during_initialization("Too small minimum heap");

  }

  if (initial_heap_byte_size() <= NewSize) {

     // make sure there is at least some room in old space

    vm_exit_during_initialization("Too small initial heap for new size specified");

  }

  if (max_heap_byte_size() < min_heap_byte_size()) {

    vm_exit_during_initialization("Incompatible minimum and maximum heap sizes specified");

  }

  if (initial_heap_byte_size() < min_heap_byte_size()) {

    vm_exit_during_initialization("Incompatible minimum and initial heap sizes specified");

  }

  if (max_heap_byte_size() < initial_heap_byte_size()) {

    vm_exit_during_initialization("Incompatible initial and maximum heap sizes specified");

  }

  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());

  }

}

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) {

  switch (rem_set_name()) {

  case GenRemSet::CardTable: {

    CardTableRS* res = new CardTableRS(whole_heap, max_covered_regions);

    return res;

  }

  default:

    guarantee(false, "unrecognized GenRemSet::Name");

    return NULL;

  }

}

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;

}

// GenCollectorPolicy methods.

size_t GenCollectorPolicy::scale_by_NewRatio_aligned(size_t base_size) {

  size_t x = base_size / (NewRatio+1);

  size_t new_gen_size = x > min_alignment() ?

                     align_size_down(x, min_alignment()) :

                     min_alignment();

  return new_gen_size;

}

size_t GenCollectorPolicy::bound_minus_alignment(size_t desired_size,

                                                 size_t maximum_size) {

  size_t alignment = min_alignment();

  size_t max_minus = maximum_size - 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::compute_max_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.

  size_t alignment = GenRemSet::max_alignment_constraint(rem_set_name());

  // 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;

}

void GenCollectorPolicy::initialize_flags() {

  // All sizes must be multiples of the generation granularity.

  set_min_alignment((uintx) Generation::GenGrain);

  set_max_alignment(compute_max_alignment());

  CollectorPolicy::initialize_flags();

  // All generational heaps have a youngest gen; handle those flags here.

  // Adjust max size parameters

  if (NewSize > MaxNewSize) {

    MaxNewSize = NewSize;

  }

  NewSize = align_size_down(NewSize, min_alignment());

  MaxNewSize = align_size_down(MaxNewSize, min_alignment());

  // Check validity of heap flags

  assert(NewSize     % min_alignment() == 0, "eden space alignment");

  assert(MaxNewSize  % min_alignment() == 0, "survivor space alignment");

  if (NewSize < 3*min_alignment()) {

     // make sure there room for eden and two survivor spaces

    vm_exit_during_initialization("Too small new size specified");

  }

  if (SurvivorRatio < 1 || NewRatio < 1) {

    vm_exit_during_initialization("Invalid heap ratio specified");

  }

}

void TwoGenerationCollectorPolicy::initialize_flags() {

  GenCollectorPolicy::initialize_flags();

  OldSize = align_size_down(OldSize, min_alignment());

  if (FLAG_IS_CMDLINE(OldSize) && FLAG_IS_DEFAULT(NewSize)) {

    // 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, max_alignment());

    MaxHeapSize = calculated_heapsize;

    InitialHeapSize = calculated_heapsize;

  }

  MaxHeapSize = align_size_up(MaxHeapSize, max_alignment());

  always_do_update_barrier = UseConcMarkSweepGC;

  // Check validity of heap flags

  assert(OldSize     % min_alignment() == 0, "old space alignment");

  assert(MaxHeapSize % max_alignment() == 0, "maximum heap alignment");

}

// 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();

  // min_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_CMDLINE(MaxNewSize) || FLAG_IS_ERGO(MaxNewSize)) {

    if (MaxNewSize < min_alignment()) {

      max_new_size = min_alignment();

    }

    if (MaxNewSize >= max_heap_byte_size()) {

      max_new_size = align_size_down(max_heap_byte_size() - min_alignment(),

                                     min_alignment());

      warning("MaxNewSize (" SIZE_FORMAT "k) is equal to or "

        "greater than the entire heap (" SIZE_FORMAT "k).  A "

        "new generation size of " SIZE_FORMAT "k will be used.",

        MaxNewSize/K, max_heap_byte_size()/K, max_new_size/K);

    } else {

      max_new_size = align_size_down(MaxNewSize, min_alignment());

    }

  // The case for FLAG_IS_ERGO(MaxNewSize) could be treated

  // specially at this point to just use an ergonomically set

  // MaxNewSize to set max_new_size.  For cases with small

  // heaps such a policy often did not work because the MaxNewSize

  // was larger than the entire heap.  The interpretation given

  // to ergonomically set flags is that the flags are set

  // by different collectors for their own special needs but

  // are not allowed to badly shape the heap.  This allows the

  // different collectors to decide what's best for themselves

  // without having to factor in the overall heap shape.  It

  // can be the case in the future that the collectors would

  // only make "wise" ergonomics choices and this policy could

  // just accept those choices.  The choices currently made are

  // not always "wise".

  } 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.

    set_min_gen0_size(max_new_size);

    set_initial_gen0_size(max_new_size);

    set_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");

    set_initial_gen0_size(desired_new_size);

    set_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.

    set_min_gen0_size(

      bound_minus_alignment(_min_gen0_size, min_heap_byte_size()));

    set_initial_gen0_size(

      bound_minus_alignment(_initial_gen0_size, initial_heap_byte_size()));

    set_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

    set_min_gen0_size(MIN2(_min_gen0_size, _max_gen0_size));

    set_initial_gen0_size(

      MAX2(MIN2(_initial_gen0_size, _max_gen0_size), _min_gen0_size));

    set_min_gen0_size(MIN2(_min_gen0_size, _initial_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());

  }

}

// 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,

                                                     const size_t min_gen1_size) {

  bool result = false;

  if ((*gen1_size_ptr + *gen0_size_ptr) > heap_size) {

    if ((heap_size < (*gen0_size_ptr + min_gen1_size)) &&

        (heap_size >= min_gen1_size + min_alignment())) {

      // Adjust gen0 down to accommodate min_gen1_size

      *gen0_size_ptr = heap_size - min_gen1_size;

      *gen0_size_ptr =

        MAX2((uintx)align_size_down(*gen0_size_ptr, min_alignment()),

             min_alignment());

      assert(*gen0_size_ptr > 0, "Min gen0 is too large");

      result = true;

    } else {

      *gen1_size_ptr = heap_size - *gen0_size_ptr;

      *gen1_size_ptr =

        MAX2((uintx)align_size_down(*gen1_size_ptr, min_alignment()),

                       min_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 = max_heap_byte_size() - _max_gen0_size;

  _max_gen1_size =

    MAX2((uintx)align_size_down(_max_gen1_size, min_alignment()),

         min_alignment());

  // If no explicit command line flag has been set for the

  // gen1 size, use what is left for gen1.

  if (FLAG_IS_DEFAULT(OldSize) || FLAG_IS_ERGO(OldSize)) {

    // The user has not specified any value or ergonomics

    // has 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.

    assert(min_heap_byte_size() > _min_gen0_size,

      "gen0 has an unexpected minimum size");

    set_min_gen1_size(min_heap_byte_size() - min_gen0_size());

    set_min_gen1_size(

      MAX2((uintx)align_size_down(_min_gen1_size, min_alignment()),

           min_alignment()));

    set_initial_gen1_size(initial_heap_byte_size() - initial_gen0_size());

    set_initial_gen1_size(

      MAX2((uintx)align_size_down(_initial_gen1_size, min_alignment()),

           min_alignment()));

  } else {

    // It's been explicitly set on the command line.  Use the

    // OldSize and then determine the consequences.

    set_min_gen1_size(OldSize);

    set_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 heap alignment.

    if ((_min_gen1_size + _min_gen0_size + min_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.