--- old/src/share/vm/gc/shared/referencePendingListLocker.cpp 2016-07-31 21:09:45.853257621 -0400 +++ /dev/null 2016-07-15 13:45:48.462218507 -0400 @@ -1,222 +0,0 @@ -/* - * Copyright (c) 2016, 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/javaClasses.hpp" -#include "classfile/systemDictionary.hpp" -#include "gc/shared/collectedHeap.hpp" -#include "gc/shared/referencePendingListLocker.hpp" -#include "memory/universe.hpp" -#include "runtime/javaCalls.hpp" -#include "utilities/preserveException.hpp" - -ReferencePendingListLockerThread::ReferencePendingListLockerThread() : - JavaThread(&start), - _monitor(Monitor::nonleaf, "ReferencePendingListLocker", false, Monitor::_safepoint_check_sometimes), - _message(NONE) {} - -ReferencePendingListLockerThread* ReferencePendingListLockerThread::create(TRAPS) { - // Create Java thread objects - instanceKlassHandle thread_klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); - instanceHandle thread_object = thread_klass->allocate_instance_handle(CHECK_NULL); - Handle thread_name = java_lang_String::create_from_str("Reference Pending List Locker", CHECK_NULL); - Handle thread_group = Universe::system_thread_group(); - JavaValue result(T_VOID); - JavaCalls::call_special(&result, - thread_object, - thread_klass, - vmSymbols::object_initializer_name(), - vmSymbols::threadgroup_string_void_signature(), - thread_group, - thread_name, - CHECK_NULL); - - { - MutexLocker ml(Threads_lock); - - // Allocate thread - ReferencePendingListLockerThread* thread = new ReferencePendingListLockerThread(); - if (thread == NULL || thread->osthread() == NULL) { - vm_exit_during_initialization("java.lang.OutOfMemoryError", - os::native_thread_creation_failed_msg()); - } - - // Initialize thread - java_lang_Thread::set_thread(thread_object(), thread); - java_lang_Thread::set_priority(thread_object(), NearMaxPriority); - java_lang_Thread::set_daemon(thread_object()); - thread->set_threadObj(thread_object()); - - // Start thread - Threads::add(thread); - Thread::start(thread); - - return thread; - } -} - -void ReferencePendingListLockerThread::start(JavaThread* thread, TRAPS) { - ReferencePendingListLockerThread* locker_thread = static_cast(thread); - locker_thread->receive_and_handle_messages(); -} - -bool ReferencePendingListLockerThread::is_hidden_from_external_view() const { - return true; -} - -void ReferencePendingListLockerThread::send_message(Message message) { - assert(message != NONE, "Should not be none"); - MonitorLockerEx ml(&_monitor, Monitor::_no_safepoint_check_flag); - - // Wait for completion of current message - while (_message != NONE) { - ml.wait(Monitor::_no_safepoint_check_flag); - } - - // Send new message - _message = message; - ml.notify_all(); - - // Wait for completion of new message - while (_message != NONE) { - ml.wait(Monitor::_no_safepoint_check_flag); - } -} - -void ReferencePendingListLockerThread::receive_and_handle_messages() { - ReferencePendingListLocker pending_list_locker; - MonitorLockerEx ml(&_monitor); - - // Main loop, never terminates - for (;;) { - // Wait for message - while (_message == NONE) { - ml.wait(); - } - - // Handle message - if (_message == LOCK) { - pending_list_locker.lock(); - } else if (_message == UNLOCK) { - pending_list_locker.unlock(); - } else { - ShouldNotReachHere(); - } - - // Clear message - _message = NONE; - ml.notify_all(); - } -} - -void ReferencePendingListLockerThread::lock() { - send_message(LOCK); -} - -void ReferencePendingListLockerThread::unlock() { - send_message(UNLOCK); -} - -bool ReferencePendingListLocker::_is_initialized = false; -ReferencePendingListLockerThread* ReferencePendingListLocker::_locker_thread = NULL; - -void ReferencePendingListLocker::initialize(bool needs_locker_thread, TRAPS) { - if (needs_locker_thread) { - _locker_thread = ReferencePendingListLockerThread::create(CHECK); - } - - _is_initialized = true; -} - -bool ReferencePendingListLocker::is_initialized() { - return _is_initialized; -} - -bool ReferencePendingListLocker::is_locked_by_self() { - oop pending_list_lock = java_lang_ref_Reference::pending_list_lock(); - if (pending_list_lock == NULL) { - return false; - } - - JavaThread* thread = JavaThread::current(); - Handle handle(thread, pending_list_lock); - return ObjectSynchronizer::current_thread_holds_lock(thread, handle); -} - -void ReferencePendingListLocker::lock() { - assert(!Heap_lock->owned_by_self(), "Heap_lock must not be owned by requesting thread"); - - if (Thread::current()->is_Java_thread()) { - assert(java_lang_ref_Reference::pending_list_lock() != NULL, "Not initialized"); - - // We may enter this with a pending exception - PRESERVE_EXCEPTION_MARK; - - HandleMark hm; - Handle handle(THREAD, java_lang_ref_Reference::pending_list_lock()); - - // Lock - ObjectSynchronizer::fast_enter(handle, &_basic_lock, false, THREAD); - - assert(is_locked_by_self(), "Locking failed"); - - if (HAS_PENDING_EXCEPTION) { - CLEAR_PENDING_EXCEPTION; - } - } else { - // Delegate operation to locker thread - assert(_locker_thread != NULL, "Locker thread not created"); - _locker_thread->lock(); - } -} - -void ReferencePendingListLocker::unlock() { - if (Thread::current()->is_Java_thread()) { - assert(java_lang_ref_Reference::pending_list_lock() != NULL, "Not initialized"); - - // We may enter this with a pending exception - PRESERVE_EXCEPTION_MARK; - - HandleMark hm; - Handle handle(THREAD, java_lang_ref_Reference::pending_list_lock()); - - assert(is_locked_by_self(), "Should be locked by self"); - - // Notify waiters if the pending list is non-empty - if (java_lang_ref_Reference::pending_list() != NULL) { - ObjectSynchronizer::notifyall(handle, THREAD); - } - - // Unlock - ObjectSynchronizer::fast_exit(handle(), &_basic_lock, THREAD); - - if (HAS_PENDING_EXCEPTION) { - CLEAR_PENDING_EXCEPTION; - } - } else { - // Delegate operation to locker thread - assert(_locker_thread != NULL, "Locker thread not created"); - _locker_thread->unlock(); - } -}