/*

 * 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.

// Align down. If the aligning result in 0, return 'alignment'.

static size_t restricted_align_down(size_t size, size_t alignment) {

  return MAX2(alignment, align_size_down_(size, alignment));

}

void CollectorPolicy::initialize_flags() {

  if (MaxHeapSize < InitialHeapSize) {

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

  }

  // Do not use FLAG_SET_ERGO to update MaxMetaspaceSize, since this will

  // override if MaxMetaspaceSize was set on the command line or not.

  // This information is needed later to conform to the specification of the

  // java.lang.management.MemoryUsage API.

  //

  // Ideally, we would be able to set the default value of MaxMetaspaceSize in

  // globals.hpp to the aligned value, but this is not possible, since the

  // alignment depends on other flags being parsed.

  if (MetaspaceSize > MaxMetaspaceSize) {

    MetaspaceSize = MaxMetaspaceSize;

  }

  assert(MetaspaceSize <= MaxMetaspaceSize, "Must be");

  if (MetaspaceSize < 256*K) {

    vm_exit_during_initialization("Too small initial Metaspace size");

  }

}

void CollectorPolicy::initialize_size_info() {

  // User inputs from -mx and ms must be aligned

  // Check heap parameter properties

    vm_exit_during_initialization("Too small initial heap");

  }

  // Check heap parameter properties

    vm_exit_during_initialization("Too small minimum heap");

  }

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

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

  }

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

  }

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

  }

    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,

  }

}

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) {

  assert(rem_set_name() == GenRemSet::CardTable, "unrecognized GenRemSet::Name");

  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_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.

  // 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.

size_t GenCollectorPolicy::scale_by_NewRatio_aligned(size_t base_size) {

  size_t x = base_size / (NewRatio+1);

  return new_gen_size;

}

size_t GenCollectorPolicy::bound_minus_alignment(size_t desired_size,

                                                 size_t maximum_size) {

  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);

}

void GenCollectorPolicy::initialize_flags() {

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

  CollectorPolicy::initialize_flags();

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

  // Adjust max size parameters

  if (NewSize > MaxNewSize) {

    MaxNewSize = NewSize;

  }

  // Check validity of heap flags

     // 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();

  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);

    MaxHeapSize = calculated_heapsize;

    InitialHeapSize = calculated_heapsize;

  }

  // adjust max heap size if necessary

  if (NewSize + OldSize > MaxHeapSize) {

    if (FLAG_IS_CMDLINE(MaxHeapSize)) {

      // 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;

      // align

      // OldSize is already aligned because above we aligned MaxHeapSize to

      OldSize = MaxHeapSize - NewSize;

    } else {

      MaxHeapSize = NewSize + OldSize;

    }

  }

  // need to do this again

  // adjust max heap size if necessary

  if (NewSize + OldSize > MaxHeapSize) {

    if (FLAG_IS_CMDLINE(MaxHeapSize)) {

      // 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;

      // align

      // OldSize is already aligned because above we aligned MaxHeapSize to

      OldSize = MaxHeapSize - NewSize;

    } else {

      MaxHeapSize = NewSize + OldSize;

    }

  }

  // need to do this again

  always_do_update_barrier = UseConcMarkSweepGC;

  // Check validity of heap 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();

  // 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)) {

    }

      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.",

    } else {

    }

  // 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 {

    // 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.

    // The maximum and minimum heap sizes are the same so

    // the generations minimum and initial must be the

    // same as its maximum.

  } 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.

      desired_new_size =

    }

    assert(_min_gen0_size > 0, "Sanity check");

    // 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.

    // 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

  }

  if (PrintGCDetails && Verbose) {

    gclog_or_tty->print_cr("1: Minimum gen0 " SIZE_FORMAT "  Initial gen0 "

      SIZE_FORMAT "  Maximum gen0 " SIZE_FORMAT,

  }

}

// 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)) &&

      // Adjust gen0 down to accommodate min_gen1_size

      *gen0_size_ptr = heap_size - min_gen1_size;

      *gen0_size_ptr =

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

      result = true;

    } else {

      *gen1_size_ptr = heap_size - *gen0_size_ptr;

      *gen1_size_ptr =

    }

  }

  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 =

  // 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.

      "gen0 has an unexpected minimum size");