/*

 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.

 * Copyright (c) 2019, Google 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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

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 */

#ifndef SHARE_GC_SHARED_GCOVERHEADCHECKER_HPP

#define SHARE_GC_SHARED_GCOVERHEADCHECKER_HPP

#include "memory/allocation.hpp"

#include "gc/shared/gcCause.hpp"

class SoftRefPolicy;

class GCOverheadTester: public StackObj {

public:

  virtual bool is_exceeded() = 0;

};

class GCOverheadChecker: public CHeapObj<mtGC> {

  // This is a hint for the heap:  we've detected that GC times

  // are taking longer than GCTimeLimit allows.

  bool _gc_overhead_limit_exceeded;

  // Use for diagnostics only.  If UseGCOverheadLimit is false,

  // this variable is still set.

  bool _print_gc_overhead_limit_would_be_exceeded;

  // Count of consecutive GC that have exceeded the

  // GC time limit criterion

  uint _gc_overhead_limit_count;

  // This flag signals that GCTimeLimit is being exceeded

  // but may not have done so for the required number of consecutive

  // collections

public:

  GCOverheadChecker();

  // This is a hint for the heap:  we've detected that gc times

  // are taking longer than GCTimeLimit allows.

  // Most heaps will choose to throw an OutOfMemoryError when

  // this occurs but it is up to the heap to request this information

  // of the policy

  bool gc_overhead_limit_exceeded() {

    return _gc_overhead_limit_exceeded;

  }

  void set_gc_overhead_limit_exceeded(bool v) {

    _gc_overhead_limit_exceeded = v;

  }

  // Tests conditions indicate the GC overhead limit is being approached.

  bool gc_overhead_limit_near() {

    return _gc_overhead_limit_count >= (GCOverheadLimitThreshold - 1);

  }

  void reset_gc_overhead_limit_count() {

    _gc_overhead_limit_count = 0;

  }

  // Check the conditions for an out-of-memory due to excessive GC time.

  // Set _gc_overhead_limit_exceeded if all the conditions have been met.

  void check_gc_overhead_limit(GCOverheadTester* time_overhead,

                               GCOverheadTester* space_overhead,

                               bool is_full_gc,

                               GCCause::Cause gc_cause,

                               SoftRefPolicy* soft_ref_policy);

};

#endif // SHARE_GC_SHARED_GCOVERHEADCHECKER_HPP