| /* |
| * Copyright (c) 2001, 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/systemDictionary.hpp" |
| #include "gc/shared/concurrentGCThread.hpp" |
| #include "oops/instanceRefKlass.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "runtime/init.hpp" |
| #include "runtime/interfaceSupport.hpp" |
| #include "runtime/java.hpp" |
| #include "runtime/javaCalls.hpp" |
| #include "runtime/os.hpp" |
| |
| ConcurrentGCThread::ConcurrentGCThread() : |
| _should_terminate(false), _has_terminated(false) { |
| }; |
| |
| void ConcurrentGCThread::create_and_start() { |
| if (os::create_thread(this, os::cgc_thread)) { |
| // XXX: need to set this to low priority |
| // unless "aggressive mode" set; priority |
| // should be just less than that of VMThread. |
| os::set_priority(this, NearMaxPriority); |
| if (!_should_terminate && !DisableStartThread) { |
| os::start_thread(this); |
| } |
| } |
| } |
| |
| void ConcurrentGCThread::initialize_in_thread() { |
| this->record_stack_base_and_size(); |
| this->initialize_named_thread(); |
| this->set_active_handles(JNIHandleBlock::allocate_block()); |
| // From this time Thread::current() should be working. |
| assert(this == Thread::current(), "just checking"); |
| } |
| |
| void ConcurrentGCThread::wait_for_universe_init() { |
| MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); |
| while (!is_init_completed() && !_should_terminate) { |
| CGC_lock->wait(Mutex::_no_safepoint_check_flag, 1); |
| } |
| } |
| |
| void ConcurrentGCThread::terminate() { |
| assert(_should_terminate, "Should only be called on terminate request."); |
| // Signal that it is terminated |
| { |
| MutexLockerEx mu(Terminator_lock, |
| Mutex::_no_safepoint_check_flag); |
| _has_terminated = true; |
| Terminator_lock->notify(); |
| } |
| } |
| |
| static void _sltLoop(JavaThread* thread, TRAPS) { |
| SurrogateLockerThread* slt = (SurrogateLockerThread*)thread; |
| slt->loop(); |
| } |
| |
| SurrogateLockerThread::SurrogateLockerThread() : |
| JavaThread(&_sltLoop), |
| _monitor(Mutex::nonleaf, "SLTMonitor", false, |
| Monitor::_safepoint_check_sometimes), |
| _buffer(empty) |
| {} |
| |
| SurrogateLockerThread* SurrogateLockerThread::make(TRAPS) { |
| Klass* k = |
| SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), |
| true, CHECK_NULL); |
| instanceKlassHandle klass (THREAD, k); |
| instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); |
| |
| const char thread_name[] = "Surrogate Locker Thread (Concurrent GC)"; |
| Handle string = java_lang_String::create_from_str(thread_name, CHECK_NULL); |
| |
| // Initialize thread_oop to put it into the system threadGroup |
| Handle thread_group (THREAD, Universe::system_thread_group()); |
| JavaValue result(T_VOID); |
| JavaCalls::call_special(&result, thread_oop, |
| klass, |
| vmSymbols::object_initializer_name(), |
| vmSymbols::threadgroup_string_void_signature(), |
| thread_group, |
| string, |
| CHECK_NULL); |
| |
| SurrogateLockerThread* res; |
| { |
| MutexLocker mu(Threads_lock); |
| res = new SurrogateLockerThread(); |
| |
| // 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 (res == NULL || res->osthread() == NULL) { |
| vm_exit_during_initialization("java.lang.OutOfMemoryError", |
| os::native_thread_creation_failed_msg()); |
| } |
| java_lang_Thread::set_thread(thread_oop(), res); |
| java_lang_Thread::set_priority(thread_oop(), NearMaxPriority); |
| java_lang_Thread::set_daemon(thread_oop()); |
| |
| res->set_threadObj(thread_oop()); |
| Threads::add(res); |
| Thread::start(res); |
| } |
| os::naked_yield(); // This seems to help with initial start-up of SLT |
| return res; |
| } |
| |
| void SurrogateLockerThread::report_missing_slt() { |
| vm_exit_during_initialization( |
| "GC before GC support fully initialized: " |
| "SLT is needed but has not yet been created."); |
| ShouldNotReachHere(); |
| } |
| |
| void SurrogateLockerThread::manipulatePLL(SLT_msg_type msg) { |
| MutexLockerEx x(&_monitor, Mutex::_no_safepoint_check_flag); |
| assert(_buffer == empty, "Should be empty"); |
| assert(msg != empty, "empty message"); |
| assert(!Heap_lock->owned_by_self(), "Heap_lock owned by requesting thread"); |
| |
| _buffer = msg; |
| while (_buffer != empty) { |
| _monitor.notify(); |
| _monitor.wait(Mutex::_no_safepoint_check_flag); |
| } |
| } |
| |
| // ======= Surrogate Locker Thread ============= |
| |
| void SurrogateLockerThread::loop() { |
| BasicLock pll_basic_lock; |
| SLT_msg_type msg; |
| debug_only(unsigned int owned = 0;) |
| |
| while (/* !isTerminated() */ 1) { |
| { |
| MutexLocker x(&_monitor); |
| // Since we are a JavaThread, we can't be here at a safepoint. |
| assert(!SafepointSynchronize::is_at_safepoint(), |
| "SLT is a JavaThread"); |
| // wait for msg buffer to become non-empty |
| while (_buffer == empty) { |
| _monitor.notify(); |
| _monitor.wait(); |
| } |
| msg = _buffer; |
| } |
| switch(msg) { |
| case acquirePLL: { |
| InstanceRefKlass::acquire_pending_list_lock(&pll_basic_lock); |
| debug_only(owned++;) |
| break; |
| } |
| case releaseAndNotifyPLL: { |
| assert(owned > 0, "Don't have PLL"); |
| InstanceRefKlass::release_and_notify_pending_list_lock(&pll_basic_lock); |
| debug_only(owned--;) |
| break; |
| } |
| case empty: |
| default: { |
| guarantee(false,"Unexpected message in _buffer"); |
| break; |
| } |
| } |
| { |
| MutexLocker x(&_monitor); |
| // Since we are a JavaThread, we can't be here at a safepoint. |
| assert(!SafepointSynchronize::is_at_safepoint(), |
| "SLT is a JavaThread"); |
| _buffer = empty; |
| _monitor.notify(); |
| } |
| } |
| assert(!_monitor.owned_by_self(), "Should unlock before exit."); |
| } |