/*

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

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 * 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.

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#include "precompiled.hpp"

#include "gc/parallel/asPSOldGen.hpp"

#include "gc/parallel/parallelScavengeHeap.hpp"

#include "gc/parallel/psAdaptiveSizePolicy.hpp"

#include "gc/parallel/psMarkSweepDecorator.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/java.hpp"

#include "utilities/align.hpp"

// Whereas PSOldGen takes the maximum size of the generation

// (which doesn't change in the case of PSOldGen) as a parameter,

// ASPSOldGen takes the upper limit on the size of

// the generation as a parameter.  In ASPSOldGen the

// maximum size of the generation can change as the boundary

// moves.  The "maximum size of the generation" is still a valid

// concept since the generation can grow and shrink within that

// maximum.  There are lots of useful checks that use that

// maximum.  In PSOldGen the method max_gen_size() returns

// _max_gen_size (as set by the PSOldGen constructor).  This

// is how it always worked.  In ASPSOldGen max_gen_size()

// returned the size of the reserved space for the generation.

// That can change as the boundary moves.  Below the limit of

// the size of the generation is passed to the PSOldGen constructor

// for "_max_gen_size" (have to pass something) but it is not used later.

//

ASPSOldGen::ASPSOldGen(size_t initial_size,

                       size_t min_size,

                       size_t size_limit,

                       const char* gen_name,

                       int level) :

  PSOldGen(initial_size, min_size, size_limit, gen_name, level),

  _gen_size_limit(size_limit)

{}

ASPSOldGen::ASPSOldGen(PSVirtualSpace* vs,

                       size_t initial_size,

                       size_t min_size,

                       size_t size_limit,

                       const char* gen_name,

                       int level) :

  PSOldGen(initial_size, min_size, size_limit, gen_name, level),

  _gen_size_limit(size_limit)

{

  _virtual_space = vs;

}

void ASPSOldGen::initialize_work(const char* perf_data_name, int level) {

  PSOldGen::initialize_work(perf_data_name, level);

  // The old gen can grow to gen_size_limit().  _reserve reflects only

  // the current maximum that can be committed.

  assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check");

  initialize_performance_counters(perf_data_name, level);

}

void ASPSOldGen::reset_after_change() {

  _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),

                        (HeapWord*)virtual_space()->high_boundary());

  post_resize();

}

size_t ASPSOldGen::available_for_expansion() {

  assert(virtual_space()->is_aligned(gen_size_limit()), "not aligned");

  assert(gen_size_limit() >= virtual_space()->committed_size(), "bad gen size");

  ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();

  size_t result =  gen_size_limit() - virtual_space()->committed_size();

  size_t result_aligned = align_down(result, heap->generation_alignment());

  return result_aligned;

}

size_t ASPSOldGen::available_for_contraction() {

  size_t uncommitted_bytes = virtual_space()->uncommitted_size();

  if (uncommitted_bytes != 0) {

    return uncommitted_bytes;

  }

  ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();

  const size_t gen_alignment = heap->generation_alignment();

  PSAdaptiveSizePolicy* policy = heap->size_policy();

  const size_t working_size =

    used_in_bytes() + (size_t) policy->avg_promoted()->padded_average();

  const size_t working_aligned = align_up(working_size, gen_alignment);

  const size_t working_or_min = MAX2(working_aligned, min_gen_size());

  if (working_or_min > reserved().byte_size()) {

    // If the used or minimum gen size (aligned up) is greater

    // than the total reserved size, then the space available

    // for contraction should (after proper alignment) be 0

    return 0;

  }

  const size_t max_contraction =

    reserved().byte_size() - working_or_min;

  // Use the "increment" fraction instead of the "decrement" fraction

  // to allow the other gen to expand more aggressively.  The

  // "decrement" fraction is conservative because its intent is to

  // only reduce the footprint.

  size_t result = policy->promo_increment_aligned_down(max_contraction);

  // Also adjust for inter-generational alignment

  size_t result_aligned = align_down(result, gen_alignment);

  Log(gc, ergo) log;

  if (log.is_trace()) {

    size_t working_promoted = (size_t) policy->avg_promoted()->padded_average();

    size_t promo_increment = policy->promo_increment(max_contraction);

    log.trace("ASPSOldGen::available_for_contraction: " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, result_aligned/K, result_aligned);

    log.trace(" reserved().byte_size() " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, reserved().byte_size()/K, reserved().byte_size());

    log.trace(" padded promoted " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, working_promoted/K, working_promoted);

    log.trace(" used " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, used_in_bytes()/K, used_in_bytes());

    log.trace(" min_gen_size() " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, min_gen_size()/K, min_gen_size());

    log.trace(" max_contraction " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, max_contraction/K, max_contraction);

    log.trace("    without alignment " SIZE_FORMAT " K / " SIZE_FORMAT_HEX, promo_increment/K, promo_increment);

    log.trace(" alignment " SIZE_FORMAT_HEX, gen_alignment);

  }

  assert(result_aligned <= max_contraction, "arithmetic is wrong");

  return result_aligned;

}