/*

 * Copyright (c) 2012, 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.

 *

 */

#include "precompiled.hpp"

#include "classfile/protectionDomainCache.hpp"

#include "classfile/stringTable.hpp"

#include "classfile/symbolTable.hpp"

#include "classfile/systemDictionary.hpp"

#include "gc/shared/oopStorage.hpp"

#include "gc/shared/oopStorageSet.hpp"

#include "memory/universe.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/interfaceSupport.inline.hpp"

#include "runtime/javaCalls.hpp"

#include "runtime/jniHandles.hpp"

#include "runtime/serviceThread.hpp"

#include "runtime/mutexLocker.hpp"

#include "runtime/os.hpp"

#include "prims/jvmtiImpl.hpp"

#include "prims/resolvedMethodTable.hpp"

#include "services/diagnosticArgument.hpp"

#include "services/diagnosticFramework.hpp"

#include "services/gcNotifier.hpp"

#include "services/lowMemoryDetector.hpp"

#include "services/threadIdTable.hpp"

ServiceThread* ServiceThread::_instance = NULL;

void ServiceThread::initialize() {

  EXCEPTION_MARK;

  const char* name = "Service Thread";

  Handle string = java_lang_String::create_from_str(name, CHECK);

  // Initialize thread_oop to put it into the system threadGroup

  Handle thread_group (THREAD, Universe::system_thread_group());

  Handle thread_oop = JavaCalls::construct_new_instance(

                          SystemDictionary::Thread_klass(),

                          vmSymbols::threadgroup_string_void_signature(),

                          thread_group,

                          string,

                          CHECK);

  {

    MutexLocker mu(Threads_lock);

    ServiceThread* thread =  new ServiceThread(&service_thread_entry);

    // At this point it may be possible that no osthread was created for the

    // JavaThread due to lack of memory. We would have to throw an exception

    // in that case. However, since this must work and we do not allow

    // exceptions anyway, check and abort if this fails.

    if (thread == NULL || thread->osthread() == NULL) {

      vm_exit_during_initialization("java.lang.OutOfMemoryError",

                                    os::native_thread_creation_failed_msg());

    }

    java_lang_Thread::set_thread(thread_oop(), thread);

    java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);

    java_lang_Thread::set_daemon(thread_oop());

    thread->set_threadObj(thread_oop());

    _instance = thread;

    Threads::add(thread);

    Thread::start(thread);

  }

}

static void cleanup_oopstorages() {

  OopStorageSet::Iterator it = OopStorageSet::all_iterator();

  for ( ; !it.is_end(); ++it) {

    it->delete_empty_blocks();

  }

}

void ServiceThread::service_thread_entry(JavaThread* jt, TRAPS) {

  while (true) {

    bool sensors_changed = false;

    bool has_jvmti_events = false;

    bool has_gc_notification_event = false;

    bool has_dcmd_notification_event = false;

    bool stringtable_work = false;

    bool symboltable_work = false;

    bool resolved_method_table_work = false;

    bool thread_id_table_work = false;

    bool protection_domain_table_work = false;

    bool oopstorage_work = false;

    JvmtiDeferredEvent jvmti_event;

    {

      // Need state transition ThreadBlockInVM so that this thread

      // will be handled by safepoint correctly when this thread is

      // notified at a safepoint.

      // This ThreadBlockInVM object is not also considered to be

      // suspend-equivalent because ServiceThread is not visible to

      // external suspension.

      ThreadBlockInVM tbivm(jt);

      MonitorLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);

      // Process all available work on each (outer) iteration, rather than

      // only the first recognized bit of work, to avoid frequently true early

      // tests from potentially starving later work.  Hence the use of

      // arithmetic-or to combine results; we don't want short-circuiting.

      while (((sensors_changed = (!UseNotificationThread && LowMemoryDetector::has_pending_requests())) |

              (has_jvmti_events = JvmtiDeferredEventQueue::has_events()) |

              (has_gc_notification_event = (!UseNotificationThread && GCNotifier::has_event())) |

              (has_dcmd_notification_event = (!UseNotificationThread && DCmdFactory::has_pending_jmx_notification())) |

              (stringtable_work = StringTable::has_work()) |

              (symboltable_work = SymbolTable::has_work()) |

              (resolved_method_table_work = ResolvedMethodTable::has_work()) |

              (thread_id_table_work = ThreadIdTable::has_work()) |

              (protection_domain_table_work = SystemDictionary::pd_cache_table()->has_work()) |

              (oopstorage_work = OopStorage::has_cleanup_work_and_reset())

             ) == 0) {

        // Wait until notified that there is some work to do.

        ml.wait();

      }

      if (has_jvmti_events) {

        jvmti_event = JvmtiDeferredEventQueue::dequeue();

      }

    }

    if (stringtable_work) {

      StringTable::do_concurrent_work(jt);

    }

    if (symboltable_work) {

      SymbolTable::do_concurrent_work(jt);

    }

    if (has_jvmti_events) {

      jvmti_event.post();

    }

    if (!UseNotificationThread) {

      if (sensors_changed) {

        LowMemoryDetector::process_sensor_changes(jt);

      }

      if(has_gc_notification_event) {

        GCNotifier::sendNotification(CHECK);

      }

      if(has_dcmd_notification_event) {

        DCmdFactory::send_notification(CHECK);

      }

    }

    if (resolved_method_table_work) {

      ResolvedMethodTable::do_concurrent_work(jt);

    }

    if (thread_id_table_work) {

      ThreadIdTable::do_concurrent_work(jt);

    }

    if (protection_domain_table_work) {

      SystemDictionary::pd_cache_table()->unlink();

    }

    if (oopstorage_work) {

      cleanup_oopstorages();

    }

  }

}

bool ServiceThread::is_service_thread(Thread* thread) {

  return thread == _instance;

}