/*

 * Copyright (c) 2014, 2017, 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.

 *

 */

#include "precompiled.hpp"

#include "classfile/stringTable.hpp"

#include "gc/g1/g1StringDedup.hpp"

#include "gc/g1/g1StringDedupQueue.hpp"

#include "gc/g1/g1StringDedupTable.hpp"

#include "gc/g1/g1StringDedupThread.hpp"

#include "gc/shared/suspendibleThreadSet.hpp"

#include "logging/log.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/atomic.hpp"

G1StringDedupThread* G1StringDedupThread::_thread = NULL;

G1StringDedupThread::G1StringDedupThread() :

  ConcurrentGCThread() {

  set_name("G1 StrDedup");

  create_and_start();

}

G1StringDedupThread::~G1StringDedupThread() {

  ShouldNotReachHere();

}

void G1StringDedupThread::create() {

  assert(G1StringDedup::is_enabled(), "String deduplication not enabled");

  assert(_thread == NULL, "One string deduplication thread allowed");

  _thread = new G1StringDedupThread();

}

G1StringDedupThread* G1StringDedupThread::thread() {

  assert(G1StringDedup::is_enabled(), "String deduplication not enabled");

  assert(_thread != NULL, "String deduplication thread not created");

  return _thread;

}

class G1StringDedupSharedClosure: public OopClosure {

 private:

  G1StringDedupStat& _stat;

 public:

  G1StringDedupSharedClosure(G1StringDedupStat& stat) : _stat(stat) {}

  virtual void do_oop(oop* p) { ShouldNotReachHere(); }

  virtual void do_oop(narrowOop* p) {

    oop java_string = oopDesc::load_decode_heap_oop(p);

    G1StringDedupTable::deduplicate(java_string, _stat);

  }

};

// The CDS archive does not include the string dedupication table. Only the string

// table is saved in the archive. The shared strings from CDS archive need to be

// added to the string dedupication table before deduplication occurs. That is

// done in the begining of the G1StringDedupThread (see G1StringDedupThread::run()

// below).

void G1StringDedupThread::deduplicate_shared_strings(G1StringDedupStat& stat) {

  G1StringDedupSharedClosure sharedStringDedup(stat);

  StringTable::shared_oops_do(&sharedStringDedup);

}

void G1StringDedupThread::run_service() {

  G1StringDedupStat total_stat;

  deduplicate_shared_strings(total_stat);

  // Main loop

  for (;;) {

    G1StringDedupStat stat;

    stat.mark_idle();

    // Wait for the queue to become non-empty

    G1StringDedupQueue::wait();

    if (should_terminate()) {

      break;

    }

    {

      // Include thread in safepoints

      SuspendibleThreadSetJoiner sts_join;

      stat.mark_exec();

      print_start(stat);

      // Process the queue

      for (;;) {

        oop java_string = G1StringDedupQueue::pop();

        if (java_string == NULL) {

          break;

        }

        G1StringDedupTable::deduplicate(java_string, stat);

        // Safepoint this thread if needed

        if (sts_join.should_yield()) {

          stat.mark_block();

          sts_join.yield();

          stat.mark_unblock();

        }

      }

      stat.mark_done();

      total_stat.add(stat);

      print_end(stat, total_stat);

    }

    G1StringDedupTable::clean_entry_cache();

  }

}

void G1StringDedupThread::stop_service() {

  G1StringDedupQueue::cancel_wait();

}

void G1StringDedupThread::print_start(const G1StringDedupStat& last_stat) {

  G1StringDedupStat::print_start(last_stat);

}

void G1StringDedupThread::print_end(const G1StringDedupStat& last_stat, const G1StringDedupStat& total_stat) {

  G1StringDedupStat::print_end(last_stat, total_stat);

  if (log_is_enabled(Debug, gc, stringdedup)) {

    G1StringDedupStat::print_statistics(last_stat, false);

    G1StringDedupStat::print_statistics(total_stat, true);

    G1StringDedupTable::print_statistics();

    G1StringDedupQueue::print_statistics();

  }

}