view src/share/vm/gc_implementation/parallelScavenge/generationSizer.hpp @ 10374:87c64c0438fb

6976350: G1: deal with fragmentation while copying objects during GC Summary: Create G1ParGCAllocBufferContainer to contain two buffers instead of previously using one buffer, in order to hold the first priority buffer longer. Thus, when some large objects hits the value of free space left in the first priority buffer it has an alternative to fit in the second priority buffer while the first priority buffer is given more chances to try allocating smaller objects. Overall, it will improve heap space efficiency. Reviewed-by: johnc, jmasa, brutisso Contributed-by: tamao <tao.mao@oracle.com>
author tamao
date Mon, 03 Jun 2013 14:37:13 -0700
parents da91efe96a93
children 9e11762cee52
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/*
 * Copyright (c) 2001, 2012, 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.
 *
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#ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_GENERATIONSIZER_HPP
#define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_GENERATIONSIZER_HPP

#include "memory/collectorPolicy.hpp"

// There is a nice batch of tested generation sizing code in
// TwoGenerationCollectorPolicy. Lets reuse it!

class GenerationSizer : public TwoGenerationCollectorPolicy {
 public:
  GenerationSizer() {
    // Partial init only!
    initialize_flags();
    initialize_size_info();
  }

  void initialize_flags() {
    // Do basic sizing work
    this->TwoGenerationCollectorPolicy::initialize_flags();

    // If the user hasn't explicitly set the number of worker
    // threads, set the count.
    assert(UseSerialGC ||
           !FLAG_IS_DEFAULT(ParallelGCThreads) ||
           (ParallelGCThreads > 0),
           "ParallelGCThreads should be set before flag initialization");

    // The survivor ratio's are calculated "raw", unlike the
    // default gc, which adds 2 to the ratio value. We need to
    // make sure the values are valid before using them.
    if (MinSurvivorRatio < 3) {
      MinSurvivorRatio = 3;
    }

    if (InitialSurvivorRatio < 3) {
      InitialSurvivorRatio = 3;
    }
  }

  size_t min_young_gen_size() { return _min_gen0_size; }
  size_t young_gen_size()     { return _initial_gen0_size; }
  size_t max_young_gen_size() { return _max_gen0_size; }

  size_t min_old_gen_size()   { return _min_gen1_size; }
  size_t old_gen_size()       { return _initial_gen1_size; }
  size_t max_old_gen_size()   { return _max_gen1_size; }

  size_t metaspace_size()      { return MetaspaceSize; }
  size_t max_metaspace_size()  { return MaxMetaspaceSize; }
};

#endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_GENERATIONSIZER_HPP