/*

 * 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.

 *

 */

#include "precompiled.hpp"

#include "gc/g1/g1Arguments.hpp"

#include "gc/g1/g1CollectedHeap.inline.hpp"

#include "gc/g1/g1HeapVerifier.hpp"

#include "gc/g1/heapRegion.hpp"

#include "gc/g1/heapRegionRemSet.hpp"

#include "gc/shared/cardTableRS.hpp"

#include "gc/shared/gcArguments.hpp"

#include "gc/shared/workerPolicy.hpp"

#include "runtime/globals.hpp"

#include "runtime/globals_extension.hpp"

static const double MaxRamFractionForYoung = 0.8;

size_t G1Arguments::MaxMemoryForYoung;

static size_t calculate_heap_alignment(size_t space_alignment) {

  size_t card_table_alignment = CardTableRS::ct_max_alignment_constraint();

  size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();

  return MAX3(card_table_alignment, space_alignment, page_size);

}

void G1Arguments::initialize_alignments() {

  // Set up the region size and associated fields.

  //

  // There is a circular dependency here. We base the region size on the heap

  // size, but the heap size should be aligned with the region size. To get

  // around this we use the unaligned values for the heap.

  HeapRegion::setup_heap_region_size(InitialHeapSize, MaxHeapSize);

  HeapRegionRemSet::setup_remset_size();

  SpaceAlignment = HeapRegion::GrainBytes;

  HeapAlignment = calculate_heap_alignment(SpaceAlignment);

}

size_t G1Arguments::conservative_max_heap_alignment() {

  return HeapRegion::max_region_size();

}

void G1Arguments::initialize_verification_types() {

  if (strlen(VerifyGCType) > 0) {

    const char delimiter[] = " ,\n";

    size_t length = strlen(VerifyGCType);

    char* type_list = NEW_C_HEAP_ARRAY(char, length + 1, mtInternal);

    strncpy(type_list, VerifyGCType, length + 1);

    char* save_ptr;

    char* token = strtok_r(type_list, delimiter, &save_ptr);

    while (token != NULL) {

      parse_verification_type(token);

      token = strtok_r(NULL, delimiter, &save_ptr);

    }

    FREE_C_HEAP_ARRAY(char, type_list);

  }

}

void G1Arguments::parse_verification_type(const char* type) {

  if (strcmp(type, "young-normal") == 0) {

    G1HeapVerifier::enable_verification_type(G1HeapVerifier::G1VerifyYoungNormal);

  } else if (strcmp(type, "concurrent-start") == 0) {

    G1HeapVerifier::enable_verification_type(G1HeapVerifier::G1VerifyConcurrentStart);

  } else if (strcmp(type, "mixed") == 0) {

    G1HeapVerifier::enable_verification_type(G1HeapVerifier::G1VerifyMixed);

  } else if (strcmp(type, "remark") == 0) {

    G1HeapVerifier::enable_verification_type(G1HeapVerifier::G1VerifyRemark);

  } else if (strcmp(type, "cleanup") == 0) {

    G1HeapVerifier::enable_verification_type(G1HeapVerifier::G1VerifyCleanup);

  } else if (strcmp(type, "full") == 0) {

    G1HeapVerifier::enable_verification_type(G1HeapVerifier::G1VerifyFull);

  } else {

    log_warning(gc, verify)("VerifyGCType: '%s' is unknown. Available types are: "

                            "young-normal, concurrent-start, mixed, remark, cleanup and full", type);

  }

}

void G1Arguments::initialize() {

  GCArguments::initialize();

  assert(UseG1GC, "Error");

  FLAG_SET_DEFAULT(ParallelGCThreads, WorkerPolicy::parallel_worker_threads());

  if (ParallelGCThreads == 0) {

    assert(!FLAG_IS_DEFAULT(ParallelGCThreads), "The default value for ParallelGCThreads should not be 0.");

    vm_exit_during_initialization("The flag -XX:+UseG1GC can not be combined with -XX:ParallelGCThreads=0", NULL);

  }

  // When dumping the CDS archive we want to reduce fragmentation by

  // triggering a full collection. To get as low fragmentation as

  // possible we only use one worker thread.

  if (DumpSharedSpaces) {

  }

  if (FLAG_IS_DEFAULT(G1ConcRefinementThreads)) {

  }

  // MarkStackSize will be set (if it hasn't been set by the user)

  // when concurrent marking is initialized.

  // Its value will be based upon the number of parallel marking threads.

  // But we do set the maximum mark stack size here.

  if (FLAG_IS_DEFAULT(MarkStackSizeMax)) {

    FLAG_SET_DEFAULT(MarkStackSizeMax, 128 * TASKQUEUE_SIZE);

  }

  if (FLAG_IS_DEFAULT(GCTimeRatio) || GCTimeRatio == 0) {

    // In G1, we want the default GC overhead goal to be higher than

    // it is for PS, or the heap might be expanded too aggressively.

    // We set it here to ~8%.

    FLAG_SET_DEFAULT(GCTimeRatio, 12);

  }

  // Below, we might need to calculate the pause time interval based on

  // the pause target. When we do so we are going to give G1 maximum

  // flexibility and allow it to do pauses when it needs to. So, we'll

  // arrange that the pause interval to be pause time target + 1 to

  // ensure that a) the pause time target is maximized with respect to

  // the pause interval and b) we maintain the invariant that pause

  // time target < pause interval. If the user does not want this

  // maximum flexibility, they will have to set the pause interval

  // explicitly.

  if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {

    // The default pause time target in G1 is 200ms

    FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);

  }

  // Then, if the interval parameter was not set, set it according to

  // the pause time target (this will also deal with the case when the

  // pause time target is the default value).

  if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {

    FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);

  }

  if (FLAG_IS_DEFAULT(ParallelRefProcEnabled) && ParallelGCThreads > 1) {

    FLAG_SET_DEFAULT(ParallelRefProcEnabled, true);

  }

  log_trace(gc)("MarkStackSize: %uk  MarkStackSizeMax: %uk", (unsigned int) (MarkStackSize / K), (uint) (MarkStackSizeMax / K));

  // By default do not let the target stack size to be more than 1/4 of the entries

  if (FLAG_IS_DEFAULT(GCDrainStackTargetSize)) {

  }

#ifdef COMPILER2

  // Enable loop strip mining to offer better pause time guarantees

  if (FLAG_IS_DEFAULT(UseCountedLoopSafepoints)) {

    FLAG_SET_DEFAULT(UseCountedLoopSafepoints, true);

    if (FLAG_IS_DEFAULT(LoopStripMiningIter)) {

      FLAG_SET_DEFAULT(LoopStripMiningIter, 1000);

    }

  }

#endif

  initialize_verification_types();

}

static size_t calculate_reasonable_max_memory_for_young(FormatBuffer<100> &calc_str, double max_ram_fraction_for_young) {

  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 * max_ram_fraction_for_young;

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

  }

  return (size_t)reasonable_max;

}

void G1Arguments::initialize_heap_flags_and_sizes() {

  if (AllocateOldGenAt != NULL) {

    initialize_heterogeneous();

  }

  GCArguments::initialize_heap_flags_and_sizes();

}

void G1Arguments::initialize_heterogeneous() {

  FormatBuffer<100> calc_str("");

  MaxMemoryForYoung = calculate_reasonable_max_memory_for_young(calc_str, MaxRamFractionForYoung);

  if (MaxNewSize > MaxMemoryForYoung) {

    if (FLAG_IS_CMDLINE(MaxNewSize)) {

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

                            MaxMemoryForYoung, 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", MaxMemoryForYoung, calc_str.buffer());

    }

    MaxNewSize = MaxMemoryForYoung;

  }

  if (NewSize > MaxMemoryForYoung) {

    if (FLAG_IS_CMDLINE(NewSize)) {

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

                            MaxMemoryForYoung, calc_str.buffer());

    }

    NewSize = MaxMemoryForYoung;

  }

}

CollectedHeap* G1Arguments::create_heap() {

  return new G1CollectedHeap();

}

bool G1Arguments::is_heterogeneous_heap() {

  return AllocateOldGenAt != NULL;

}

size_t G1Arguments::reasonable_max_memory_for_young() {

  return MaxMemoryForYoung;

}

size_t G1Arguments::heap_reserved_size_bytes() {

  return (is_heterogeneous_heap() ? 2 : 1) * MaxHeapSize;

}