/*

 * Copyright (c) 2018, 2019, 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.

 *

 */

#include "precompiled.hpp"

#include "gc/shared/cardTableRS.hpp"

#include "gc/shared/gcArguments.hpp"

#include "logging/log.hpp"

#include "runtime/arguments.hpp"

#include "runtime/globals.hpp"

#include "runtime/globals_extension.hpp"

#include "utilities/defaultStream.hpp"

#include "utilities/macros.hpp"

size_t HeapAlignment = 0;

size_t SpaceAlignment = 0;

void GCArguments::initialize() {

  if (FullGCALot && FLAG_IS_DEFAULT(MarkSweepAlwaysCompactCount)) {

    MarkSweepAlwaysCompactCount = 1;  // Move objects every gc.

  }

  if (!(UseParallelGC || UseParallelOldGC) && FLAG_IS_DEFAULT(ScavengeBeforeFullGC)) {

    FLAG_SET_DEFAULT(ScavengeBeforeFullGC, false);

  }

  if (GCTimeLimit == 100) {

    // Turn off gc-overhead-limit-exceeded checks

    FLAG_SET_DEFAULT(UseGCOverheadLimit, false);

  }

  if (MinHeapFreeRatio == 100) {

    // Keeping the heap 100% free is hard ;-) so limit it to 99%.

    FLAG_SET_ERGO(MinHeapFreeRatio, 99);

  }

  if (!ClassUnloading) {

    // If class unloading is disabled, also disable concurrent class unloading.

    FLAG_SET_CMDLINE(ClassUnloadingWithConcurrentMark, false);

  }

  if (!FLAG_IS_DEFAULT(AllocateOldGenAt)) {

    // CompressedOops not supported when AllocateOldGenAt is set.

    LP64_ONLY(FLAG_SET_DEFAULT(UseCompressedOops, false));

    LP64_ONLY(FLAG_SET_DEFAULT(UseCompressedClassPointers, false));

    // When AllocateOldGenAt is set, we cannot use largepages for entire heap memory.

    // Only young gen which is allocated in dram can use large pages, but we currently don't support that.

    FLAG_SET_DEFAULT(UseLargePages, false);

  }

}

void GCArguments::initialize_heap_sizes() {

  initialize_alignments();

  initialize_heap_flags_and_sizes();

  initialize_size_info();

}

size_t GCArguments::compute_heap_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 = CardTableRS::ct_max_alignment_constraint();

  if (UseLargePages) {

      // 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;

}

bool GCArguments::check_args_consistency() {

  bool status = true;

  if (!FLAG_IS_DEFAULT(AllocateHeapAt) && !FLAG_IS_DEFAULT(AllocateOldGenAt)) {

    jio_fprintf(defaultStream::error_stream(),

      "AllocateHeapAt and AllocateOldGenAt cannot be used together.\n");

    status = false;

  }

  if (!FLAG_IS_DEFAULT(AllocateOldGenAt) && (UseSerialGC || UseConcMarkSweepGC || UseEpsilonGC || UseZGC)) {

    jio_fprintf(defaultStream::error_stream(),

      "AllocateOldGenAt is not supported for selected GC.\n");

    status = false;

  }

  return status;

}

#ifdef ASSERT

void GCArguments::assert_flags() {

  assert(InitialHeapSize <= MaxHeapSize, "Ergonomics decided on incompatible initial and maximum heap sizes");

  assert(InitialHeapSize % HeapAlignment == 0, "InitialHeapSize alignment");

  assert(MaxHeapSize % HeapAlignment == 0, "MaxHeapSize alignment");

}

void GCArguments::assert_size_info() {

  assert(MaxHeapSize >= MinHeapSize, "Ergonomics decided on incompatible minimum and maximum heap sizes");

  assert(InitialHeapSize >= MinHeapSize, "Ergonomics decided on incompatible initial and minimum heap sizes");

  assert(MaxHeapSize >= InitialHeapSize, "Ergonomics decided on incompatible initial and maximum heap sizes");

  assert(MinHeapSize % HeapAlignment == 0, "MinHeapSize alignment");

  assert(InitialHeapSize % HeapAlignment == 0, "InitialHeapSize alignment");

  assert(MaxHeapSize % HeapAlignment == 0, "MaxHeapSize alignment");

}

#endif // ASSERT

void GCArguments::initialize_size_info() {

  log_debug(gc, heap)("Minimum heap " SIZE_FORMAT "  Initial heap " SIZE_FORMAT "  Maximum heap " SIZE_FORMAT,

                      MinHeapSize, InitialHeapSize, MaxHeapSize);

  DEBUG_ONLY(assert_size_info();)

}

void GCArguments::initialize_heap_flags_and_sizes() {

  assert(SpaceAlignment != 0, "Space alignment not set up properly");

  assert(HeapAlignment != 0, "Heap alignment not set up properly");

  assert(HeapAlignment >= SpaceAlignment,

         "HeapAlignment: " SIZE_FORMAT " less than SpaceAlignment: " SIZE_FORMAT,

         HeapAlignment, SpaceAlignment);

  assert(HeapAlignment % SpaceAlignment == 0,

         "HeapAlignment: " SIZE_FORMAT " not aligned by SpaceAlignment: " SIZE_FORMAT,

         HeapAlignment, SpaceAlignment);

  if (FLAG_IS_CMDLINE(MaxHeapSize)) {

    if (FLAG_IS_CMDLINE(InitialHeapSize) && InitialHeapSize > MaxHeapSize) {

      vm_exit_during_initialization("Initial heap size set to a larger value than the maximum heap size");

    }

    if (FLAG_IS_CMDLINE(MinHeapSize) && MaxHeapSize < MinHeapSize) {

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

    }

  }

  // Check heap parameter properties

  if (MaxHeapSize < 2 * M) {

    vm_exit_during_initialization("Too small maximum heap");

  }

  if (InitialHeapSize < M) {

    vm_exit_during_initialization("Too small initial heap");

  }

  if (MinHeapSize < M) {

    vm_exit_during_initialization("Too small minimum heap");

  }

  // User inputs from -Xmx and -Xms must be aligned

  // Write back to flags if the values changed

  if (!is_aligned(MinHeapSize, HeapAlignment)) {

    FLAG_SET_ERGO(MinHeapSize, align_up(MinHeapSize, HeapAlignment));

  }

  if (!is_aligned(InitialHeapSize, HeapAlignment)) {

    FLAG_SET_ERGO(InitialHeapSize, align_up(InitialHeapSize, HeapAlignment));

  }

  if (!is_aligned(MaxHeapSize, HeapAlignment)) {

    FLAG_SET_ERGO(MaxHeapSize, align_up(MaxHeapSize, HeapAlignment));

  }

  if (FLAG_IS_CMDLINE(InitialHeapSize) && FLAG_IS_CMDLINE(MinHeapSize) &&

      InitialHeapSize < MinHeapSize) {

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

  }

  if (!FLAG_IS_DEFAULT(InitialHeapSize) && InitialHeapSize > MaxHeapSize) {

    FLAG_SET_ERGO(MaxHeapSize, InitialHeapSize);

  } else if (!FLAG_IS_DEFAULT(MaxHeapSize) && InitialHeapSize > MaxHeapSize) {

    FLAG_SET_ERGO(InitialHeapSize, MaxHeapSize);

    if (InitialHeapSize < MinHeapSize) {

      FLAG_SET_ERGO(MinHeapSize, InitialHeapSize);

    }

  }

  if (FLAG_IS_DEFAULT(SoftMaxHeapSize)) {

    FLAG_SET_ERGO(SoftMaxHeapSize, MaxHeapSize);

  }

  FLAG_SET_ERGO(MinHeapDeltaBytes, align_up(MinHeapDeltaBytes, SpaceAlignment));

  DEBUG_ONLY(assert_flags();)

}