/*

 * 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/heapRegion.hpp"

#include "runtime/globals.hpp"

#include "runtime/globals_extension.hpp"

#include "runtime/vm_version.hpp"

size_t G1Arguments::conservative_max_heap_alignment() {

  return HeapRegion::max_region_size();

}

void G1Arguments::initialize_flags() {

  GCArguments::initialize_flags();

  assert(UseG1GC, "Error");

#if defined(COMPILER1) || INCLUDE_JVMCI

  FastTLABRefill = false;

#endif

  FLAG_SET_DEFAULT(ParallelGCThreads, Abstract_VM_Version::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);

  }

#if INCLUDE_ALL_GCS

  if (FLAG_IS_DEFAULT(G1ConcRefinementThreads)) {

    FLAG_SET_ERGO(uint, G1ConcRefinementThreads, ParallelGCThreads);

  }

#endif

  // 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);

  }

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

}