/*

 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.

 * Copyright (c) 2017, Red Hat, Inc. and/or its affiliates.

 * 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.

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 */

#include "precompiled.hpp"

#include "gc/parallel/parallelArguments.hpp"

#include "gc/parallel/parallelScavengeHeap.hpp"

#include "gc/shared/adaptiveSizePolicy.hpp"

#include "gc/shared/gcArguments.hpp"

#include "gc/shared/genArguments.hpp"

#include "gc/shared/workerPolicy.hpp"

#include "logging/log.hpp"

#include "runtime/globals.hpp"

#include "runtime/globals_extension.hpp"

#include "runtime/java.hpp"

#include "utilities/defaultStream.hpp"

static const double MaxRamFractionForYoung = 0.8;

size_t ParallelArguments::conservative_max_heap_alignment() {

  return compute_heap_alignment();

}

void ParallelArguments::initialize() {

  GCArguments::initialize();

  assert(UseParallelGC || UseParallelOldGC, "Error");

  // Enable ParallelOld unless it was explicitly disabled (cmd line or rc file).

  if (FLAG_IS_DEFAULT(UseParallelOldGC)) {

    FLAG_SET_DEFAULT(UseParallelOldGC, true);

  }

  FLAG_SET_DEFAULT(UseParallelGC, true);

  // If no heap maximum was requested explicitly, use some reasonable fraction

  // of the physical memory, up to a maximum of 1GB.

  FLAG_SET_DEFAULT(ParallelGCThreads,

                   WorkerPolicy::parallel_worker_threads());

  if (ParallelGCThreads == 0) {

    jio_fprintf(defaultStream::error_stream(),

        "The Parallel GC can not be combined with -XX:ParallelGCThreads=0\n");

    vm_exit(1);

  }

  if (UseAdaptiveSizePolicy) {

    // We don't want to limit adaptive heap sizing's freedom to adjust the heap

    // unless the user actually sets these flags.

    if (FLAG_IS_DEFAULT(MinHeapFreeRatio)) {

      FLAG_SET_DEFAULT(MinHeapFreeRatio, 0);

    }

    if (FLAG_IS_DEFAULT(MaxHeapFreeRatio)) {

      FLAG_SET_DEFAULT(MaxHeapFreeRatio, 100);

    }

  }

  // If InitialSurvivorRatio or MinSurvivorRatio were not specified, but the

  // SurvivorRatio has been set, reset their default values to SurvivorRatio +

  // 2.  By doing this we make SurvivorRatio also work for Parallel Scavenger.

  // See CR 6362902 for details.

  if (!FLAG_IS_DEFAULT(SurvivorRatio)) {

    if (FLAG_IS_DEFAULT(InitialSurvivorRatio)) {

       FLAG_SET_DEFAULT(InitialSurvivorRatio, SurvivorRatio + 2);

    }

    if (FLAG_IS_DEFAULT(MinSurvivorRatio)) {

      FLAG_SET_DEFAULT(MinSurvivorRatio, SurvivorRatio + 2);

    }

  }

  if (UseParallelOldGC) {

    // Par compact uses lower default values since they are treated as

    // minimums.  These are different defaults because of the different

    // interpretation and are not ergonomically set.

    if (FLAG_IS_DEFAULT(MarkSweepDeadRatio)) {

      FLAG_SET_DEFAULT(MarkSweepDeadRatio, 1);

    }

  }

}

// The alignment used for boundary between young gen and old gen

static size_t default_gen_alignment() {

  return 64 * K * HeapWordSize;

}

void ParallelArguments::initialize_alignments() {

  SpaceAlignment = GenAlignment = default_gen_alignment();

  HeapAlignment = compute_heap_alignment();

}

void ParallelArguments::initialize_heap_flags_and_sizes_one_pass() {

  // Do basic sizing work

  GenArguments::initialize_heap_flags_and_sizes();

  // 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) {

    FLAG_SET_ERGO(MinSurvivorRatio, 3);

  }

  if (InitialSurvivorRatio < 3) {

    FLAG_SET_ERGO(InitialSurvivorRatio, 3);

  }

}

void ParallelArguments::initialize_heap_flags_and_sizes() {

  if (is_heterogeneous_heap()) {

    initialize_heterogeneous();

  }

  initialize_heap_flags_and_sizes_one_pass();

  const size_t max_page_sz = os::page_size_for_region_aligned(MaxHeapSize, 8);

  const size_t min_pages = 4; // 1 for eden + 1 for each survivor + 1 for old

  const size_t min_page_sz = os::page_size_for_region_aligned(MinHeapSize, min_pages);

  const size_t page_sz = MIN2(max_page_sz, min_page_sz);

  // Can a page size be something else than a power of two?

  assert(is_power_of_2((intptr_t)page_sz), "must be a power of 2");

  size_t new_alignment = align_up(page_sz, GenAlignment);

  if (new_alignment != GenAlignment) {

    GenAlignment = new_alignment;

    SpaceAlignment = new_alignment;

    // Redo everything from the start

    initialize_heap_flags_and_sizes_one_pass();

  }

}

// Check the available dram memory to limit NewSize and MaxNewSize before

// calling base class initialize_flags().

void ParallelArguments::initialize_heterogeneous() {

  FormatBuffer<100> calc_str("");

  julong phys_mem;

  // If MaxRam is specified, we use that as maximum physical memory available.

  if (FLAG_IS_DEFAULT(MaxRAM)) {

    phys_mem = os::physical_memory();

    calc_str.append("Physical_Memory");

  } else {

    phys_mem = (julong)MaxRAM;

    calc_str.append("MaxRAM");

  }

  julong reasonable_max = phys_mem;

  // If either MaxRAMFraction or MaxRAMPercentage is specified, we use them to calculate

  // reasonable max size of young generation.

  if (!FLAG_IS_DEFAULT(MaxRAMFraction)) {

    reasonable_max = (julong)(phys_mem / MaxRAMFraction);

    calc_str.append(" / MaxRAMFraction");

  } else if (!FLAG_IS_DEFAULT(MaxRAMPercentage)) {

    reasonable_max = (julong)((phys_mem * MaxRAMPercentage) / 100);

    calc_str.append(" * MaxRAMPercentage / 100");

  } else {

    // We use our own fraction to calculate max size of young generation.

    reasonable_max = phys_mem * MaxRamFractionForYoung;

    calc_str.append(" * %0.2f", MaxRamFractionForYoung);

  }

  reasonable_max = align_up(reasonable_max, GenAlignment);

  if (MaxNewSize > reasonable_max) {

    if (FLAG_IS_CMDLINE(MaxNewSize)) {

      log_warning(gc, ergo)("Setting MaxNewSize to " SIZE_FORMAT " based on dram available (calculation = align(%s))",

                            (size_t)reasonable_max, calc_str.buffer());

    } else {

      log_info(gc, ergo)("Setting MaxNewSize to " SIZE_FORMAT " based on dram available (calculation = align(%s)). "

                         "Dram usage can be lowered by setting MaxNewSize to a lower value", (size_t)reasonable_max, calc_str.buffer());

    }

    MaxNewSize = reasonable_max;

  }

  if (NewSize > reasonable_max) {

    if (FLAG_IS_CMDLINE(NewSize)) {

      log_warning(gc, ergo)("Setting NewSize to " SIZE_FORMAT " based on dram available (calculation = align(%s))",

                            (size_t)reasonable_max, calc_str.buffer());

    }

    NewSize = reasonable_max;

  }

}

bool ParallelArguments::is_heterogeneous_heap() {

  return AllocateOldGenAt != NULL;

}

size_t ParallelArguments::heap_reserved_size_bytes() {

  if (!is_heterogeneous_heap() || !UseAdaptiveGCBoundary) {

    return MaxHeapSize;

  }

  // Heterogeneous heap and adaptive size gc boundary

  // This is the size that young gen can grow to, when UseAdaptiveGCBoundary is true.

  size_t max_yg_size = MaxHeapSize - MinOldSize;

  // This is the size that old gen can grow to, when UseAdaptiveGCBoundary is true.

  size_t max_old_size = MaxHeapSize - MinNewSize;

  return max_yg_size + max_old_size;

}

CollectedHeap* ParallelArguments::create_heap() {

  return new ParallelScavengeHeap();

}