/*

 * Copyright (c) 2019, SAP SE. All rights reserved.

 * Copyright (c) 2019, Oracle 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

 * questions.

 *

 */

#ifndef SHARE_MEMORY_METASPACE_COMMITLIMITER_HPP

#define SHARE_MEMORY_METASPACE_COMMITLIMITER_HPP

#include "memory/allocation.hpp"

#include "memory/metaspace/counter.hpp"

namespace metaspace {

class CommitLimiter : public CHeapObj<mtInternal> {

  // Counts total words committed for metaspace

  SizeCounter _cnt;

  // Purely for testing purposes: cap, in words.

  const size_t _cap;

public:

  // Create a commit limiter. This is only useful for testing, with a cap != 0,

  // since normal code should use the global commit limiter.

  // If cap != 0 (word size), the cap replaces the internal logic of limiting.

  CommitLimiter(size_t cap = 0) : _cnt(), _cap(cap) {}

  // Returns the size, in words, by which we may expand the metaspace committed area without:

  // - _cap == 0: hitting GC threshold or the MaxMetaspaceSize

  // - _cap > 0: hitting cap (this is just for testing purposes)

  size_t possible_expansion_words() const;

  void increase_committed(size_t word_size)   { _cnt.increment_by(word_size); }

  void decrease_committed(size_t word_size)   { _cnt.decrement_by(word_size); }

  size_t committed_words() const              { return _cnt.get(); }

  // Returns the global metaspace commit counter

  static CommitLimiter* globalLimiter();

};

} // namespace metaspace

#endif // SHARE_MEMORY_METASPACE_COMMITLIMITER_HPP