/*

 * Copyright (c) 2018, 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_VM_GC_SHARED_PARALLELCLEANING_HPP

#define SHARE_VM_GC_SHARED_PARALLELCLEANING_HPP

#include "gc/shared/oopStorageParState.hpp"

#include "gc/shared/stringdedup/stringDedup.hpp"

#include "gc/shared/workgroup.hpp"

class ParallelCleaningTask;

class StringCleaningTask : public AbstractGangTask {

private:

  BoolObjectClosure* _is_alive;

  StringDedupUnlinkOrOopsDoClosure * const _dedup_closure;

  OopStorage::ParState<false /* concurrent */, false /* const */> _par_state_string;

  int _initial_string_table_size;

  bool            _process_strings;

  volatile size_t _strings_processed;

  volatile size_t _strings_removed;

public:

  StringCleaningTask(BoolObjectClosure* is_alive, StringDedupUnlinkOrOopsDoClosure* dedup_closure, bool process_strings);

  ~StringCleaningTask();

  void work(uint worker_id);

  size_t strings_processed() const { return _strings_processed; }

  size_t strings_removed()   const { return _strings_removed; }

};

class CodeCacheUnloadingTask {

private:

  static Monitor* _lock;

  BoolObjectClosure* const _is_alive;

  const bool               _unloading_occurred;

  const uint               _num_workers;

  // Variables used to claim nmethods.

  CompiledMethod* _first_nmethod;

  CompiledMethod* volatile _claimed_nmethod;

  // The list of nmethods that need to be processed by the second pass.

  CompiledMethod* volatile _postponed_list;

  volatile uint            _num_entered_barrier;

public:

  CodeCacheUnloadingTask(uint num_workers, BoolObjectClosure* is_alive, bool unloading_occurred);

  ~CodeCacheUnloadingTask();

private:

  void add_to_postponed_list(CompiledMethod* nm);

  void clean_nmethod(CompiledMethod* nm);

  void clean_nmethod_postponed(CompiledMethod* nm);

  static const int MaxClaimNmethods = 16;

  void claim_nmethods(CompiledMethod** claimed_nmethods, int *num_claimed_nmethods);

  CompiledMethod* claim_postponed_nmethod();

public:

  // Mark that we're done with the first pass of nmethod cleaning.

  void barrier_mark(uint worker_id);

  // See if we have to wait for the other workers to

  // finish their first-pass nmethod cleaning work.

  void barrier_wait(uint worker_id);

  // Cleaning and unloading of nmethods. Some work has to be postponed

  // to the second pass, when we know which nmethods survive.

  void work_first_pass(uint worker_id);

  void work_second_pass(uint worker_id);

};

class KlassCleaningTask : public StackObj {

  volatile int                            _clean_klass_tree_claimed;

  ClassLoaderDataGraphKlassIteratorAtomic _klass_iterator;

public:

  KlassCleaningTask();

private:

  bool claim_clean_klass_tree_task();

  InstanceKlass* claim_next_klass();

public:

  void clean_klass(InstanceKlass* ik) {

    ik->clean_weak_instanceklass_links();

  }

  void work();

};

// To minimize the remark pause times, the tasks below are done in parallel.

class ParallelCleaningTask : public AbstractGangTask {

private:

  bool                        _unloading_occurred;

  StringCleaningTask          _string_task;

  CodeCacheUnloadingTask      _code_cache_task;

  KlassCleaningTask           _klass_cleaning_task;

public:

  // The constructor is run in the VMThread.

  ParallelCleaningTask(BoolObjectClosure* is_alive, StringDedupUnlinkOrOopsDoClosure* dedup_closure,

    uint num_workers, bool unloading_occurred);

  void work(uint worker_id);

};

#endif // SHARE_VM_GC_SHARED_PARALLELCLEANING_HPP