ysr@777: /*
coleenp@4037:  * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
ysr@777:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
ysr@777:  *
ysr@777:  * This code is free software; you can redistribute it and/or modify it
ysr@777:  * under the terms of the GNU General Public License version 2 only, as
ysr@777:  * published by the Free Software Foundation.
ysr@777:  *
ysr@777:  * This code is distributed in the hope that it will be useful, but WITHOUT
ysr@777:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
ysr@777:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
ysr@777:  * version 2 for more details (a copy is included in the LICENSE file that
ysr@777:  * accompanied this code).
ysr@777:  *
ysr@777:  * You should have received a copy of the GNU General Public License version
ysr@777:  * 2 along with this work; if not, write to the Free Software Foundation,
ysr@777:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
ysr@777:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
ysr@777:  *
ysr@777:  */
ysr@777: 
stefank@2314: #include "precompiled.hpp"
stefank@2314: #include "classfile/systemDictionary.hpp"
stefank@2314: #include "gc_implementation/shared/concurrentGCThread.hpp"
stefank@2314: #include "oops/instanceRefKlass.hpp"
stefank@2314: #include "oops/oop.inline.hpp"
stefank@2314: #include "runtime/init.hpp"
stefank@2314: #include "runtime/interfaceSupport.hpp"
stefank@2314: #include "runtime/java.hpp"
stefank@2314: #include "runtime/javaCalls.hpp"
stefank@2314: 
ysr@777: // CopyrightVersion 1.2
ysr@777: 
ysr@777: int  ConcurrentGCThread::_CGC_flag            = CGC_nil;
ysr@777: 
ysr@777: SuspendibleThreadSet ConcurrentGCThread::_sts;
ysr@777: 
iveresov@1229: ConcurrentGCThread::ConcurrentGCThread() :
iveresov@1229:   _should_terminate(false), _has_terminated(false) {
ysr@777:   _sts.initialize();
ysr@777: };
ysr@777: 
ysr@777: void ConcurrentGCThread::safepoint_synchronize() {
ysr@777:   _sts.suspend_all();
ysr@777: }
ysr@777: 
ysr@777: void ConcurrentGCThread::safepoint_desynchronize() {
ysr@777:   _sts.resume_all();
ysr@777: }
ysr@777: 
ysr@777: void ConcurrentGCThread::create_and_start() {
ysr@777:   if (os::create_thread(this, os::cgc_thread)) {
ysr@777:     // XXX: need to set this to low priority
ysr@777:     // unless "agressive mode" set; priority
ysr@777:     // should be just less than that of VMThread.
ysr@777:     os::set_priority(this, NearMaxPriority);
ysr@777:     if (!_should_terminate && !DisableStartThread) {
ysr@777:       os::start_thread(this);
ysr@777:     }
ysr@777:   }
ysr@777: }
ysr@777: 
ysr@777: void ConcurrentGCThread::initialize_in_thread() {
ysr@777:   this->record_stack_base_and_size();
ysr@777:   this->initialize_thread_local_storage();
ysr@777:   this->set_active_handles(JNIHandleBlock::allocate_block());
ysr@777:   // From this time Thread::current() should be working.
ysr@777:   assert(this == Thread::current(), "just checking");
ysr@777: }
ysr@777: 
ysr@777: void ConcurrentGCThread::wait_for_universe_init() {
ysr@777:   MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag);
ysr@777:   while (!is_init_completed() && !_should_terminate) {
ysr@777:     CGC_lock->wait(Mutex::_no_safepoint_check_flag, 200);
ysr@777:   }
ysr@777: }
ysr@777: 
ysr@777: void ConcurrentGCThread::terminate() {
ysr@777:   // Signal that it is terminated
ysr@777:   {
ysr@777:     MutexLockerEx mu(Terminator_lock,
ysr@777:                      Mutex::_no_safepoint_check_flag);
ysr@777:     _has_terminated = true;
ysr@777:     Terminator_lock->notify();
ysr@777:   }
ysr@777: 
ysr@777:   // Thread destructor usually does this..
ysr@777:   ThreadLocalStorage::set_thread(NULL);
ysr@777: }
ysr@777: 
ysr@777: 
ysr@777: void SuspendibleThreadSet::initialize_work() {
ysr@777:   MutexLocker x(STS_init_lock);
ysr@777:   if (!_initialized) {
ysr@777:     _m             = new Monitor(Mutex::leaf,
ysr@777:                                  "SuspendibleThreadSetLock", true);
ysr@777:     _async         = 0;
ysr@777:     _async_stop    = false;
ysr@777:     _async_stopped = 0;
ysr@777:     _initialized   = true;
ysr@777:   }
ysr@777: }
ysr@777: 
ysr@777: void SuspendibleThreadSet::join() {
ysr@777:   initialize();
ysr@777:   MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
ysr@777:   while (_async_stop) _m->wait(Mutex::_no_safepoint_check_flag);
ysr@777:   _async++;
ysr@777:   assert(_async > 0, "Huh.");
ysr@777: }
ysr@777: 
ysr@777: void SuspendibleThreadSet::leave() {
ysr@777:   assert(_initialized, "Must be initialized.");
ysr@777:   MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
ysr@777:   _async--;
ysr@777:   assert(_async >= 0, "Huh.");
ysr@777:   if (_async_stop) _m->notify_all();
ysr@777: }
ysr@777: 
ysr@777: void SuspendibleThreadSet::yield(const char* id) {
ysr@777:   assert(_initialized, "Must be initialized.");
ysr@777:   if (_async_stop) {
ysr@777:     MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
ysr@777:     if (_async_stop) {
ysr@777:       _async_stopped++;
ysr@777:       assert(_async_stopped > 0, "Huh.");
ysr@777:       if (_async_stopped == _async) {
ysr@777:         if (ConcGCYieldTimeout > 0) {
ysr@777:           double now = os::elapsedTime();
ysr@777:           guarantee((now - _suspend_all_start) * 1000.0 <
ysr@777:                     (double)ConcGCYieldTimeout,
ysr@777:                     "Long delay; whodunit?");
ysr@777:         }
ysr@777:       }
ysr@777:       _m->notify_all();
ysr@777:       while (_async_stop) _m->wait(Mutex::_no_safepoint_check_flag);
ysr@777:       _async_stopped--;
ysr@777:       assert(_async >= 0, "Huh");
ysr@777:       _m->notify_all();
ysr@777:     }
ysr@777:   }
ysr@777: }
ysr@777: 
ysr@777: void SuspendibleThreadSet::suspend_all() {
ysr@777:   initialize();  // If necessary.
ysr@777:   if (ConcGCYieldTimeout > 0) {
ysr@777:     _suspend_all_start = os::elapsedTime();
ysr@777:   }
ysr@777:   MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
ysr@777:   assert(!_async_stop, "Only one at a time.");
ysr@777:   _async_stop = true;
ysr@777:   while (_async_stopped < _async) _m->wait(Mutex::_no_safepoint_check_flag);
ysr@777: }
ysr@777: 
ysr@777: void SuspendibleThreadSet::resume_all() {
ysr@777:   assert(_initialized, "Must be initialized.");
ysr@777:   MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
ysr@777:   assert(_async_stopped == _async, "Huh.");
ysr@777:   _async_stop = false;
ysr@777:   _m->notify_all();
ysr@777: }
ysr@777: 
ysr@777: static void _sltLoop(JavaThread* thread, TRAPS) {
ysr@777:   SurrogateLockerThread* slt = (SurrogateLockerThread*)thread;
ysr@777:   slt->loop();
ysr@777: }
ysr@777: 
ysr@777: SurrogateLockerThread::SurrogateLockerThread() :
ysr@777:   JavaThread(&_sltLoop),
ysr@777:   _monitor(Mutex::nonleaf, "SLTMonitor"),
ysr@777:   _buffer(empty)
ysr@777: {}
ysr@777: 
ysr@777: SurrogateLockerThread* SurrogateLockerThread::make(TRAPS) {
coleenp@4037:   Klass* k =
coleenp@2497:     SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(),
ysr@777:                                       true, CHECK_NULL);
ysr@777:   instanceKlassHandle klass (THREAD, k);
ysr@777:   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
ysr@777: 
tonyp@2197:   const char thread_name[] = "Surrogate Locker Thread (Concurrent GC)";
ysr@777:   Handle string = java_lang_String::create_from_str(thread_name, CHECK_NULL);
ysr@777: 
ysr@777:   // Initialize thread_oop to put it into the system threadGroup
ysr@777:   Handle thread_group (THREAD, Universe::system_thread_group());
ysr@777:   JavaValue result(T_VOID);
ysr@777:   JavaCalls::call_special(&result, thread_oop,
ysr@777:                           klass,
coleenp@2497:                           vmSymbols::object_initializer_name(),
coleenp@2497:                           vmSymbols::threadgroup_string_void_signature(),
ysr@777:                           thread_group,
ysr@777:                           string,
ysr@777:                           CHECK_NULL);
ysr@777: 
ysr@777:   SurrogateLockerThread* res;
ysr@777:   {
ysr@777:     MutexLocker mu(Threads_lock);
ysr@777:     res = new SurrogateLockerThread();
ysr@777: 
ysr@777:     // At this point it may be possible that no osthread was created for the
ysr@777:     // JavaThread due to lack of memory. We would have to throw an exception
ysr@777:     // in that case. However, since this must work and we do not allow
ysr@777:     // exceptions anyway, check and abort if this fails.
ysr@777:     if (res == NULL || res->osthread() == NULL) {
ysr@777:       vm_exit_during_initialization("java.lang.OutOfMemoryError",
ysr@777:                                     "unable to create new native thread");
ysr@777:     }
ysr@777:     java_lang_Thread::set_thread(thread_oop(), res);
ysr@777:     java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
ysr@777:     java_lang_Thread::set_daemon(thread_oop());
ysr@777: 
ysr@777:     res->set_threadObj(thread_oop());
ysr@777:     Threads::add(res);
ysr@777:     Thread::start(res);
ysr@777:   }
ysr@777:   os::yield(); // This seems to help with initial start-up of SLT
ysr@777:   return res;
ysr@777: }
ysr@777: 
ysr@777: void SurrogateLockerThread::manipulatePLL(SLT_msg_type msg) {
ysr@777:   MutexLockerEx x(&_monitor, Mutex::_no_safepoint_check_flag);
ysr@777:   assert(_buffer == empty, "Should be empty");
ysr@777:   assert(msg != empty, "empty message");
johnc@3218:   assert(!Heap_lock->owned_by_self(), "Heap_lock owned by requesting thread");
johnc@3218: 
ysr@777:   _buffer = msg;
ysr@777:   while (_buffer != empty) {
ysr@777:     _monitor.notify();
ysr@777:     _monitor.wait(Mutex::_no_safepoint_check_flag);
ysr@777:   }
ysr@777: }
ysr@777: 
ysr@777: // ======= Surrogate Locker Thread =============
ysr@777: 
ysr@777: void SurrogateLockerThread::loop() {
ysr@777:   BasicLock pll_basic_lock;
ysr@777:   SLT_msg_type msg;
ysr@777:   debug_only(unsigned int owned = 0;)
ysr@777: 
ysr@777:   while (/* !isTerminated() */ 1) {
ysr@777:     {
ysr@777:       MutexLocker x(&_monitor);
ysr@777:       // Since we are a JavaThread, we can't be here at a safepoint.
ysr@777:       assert(!SafepointSynchronize::is_at_safepoint(),
ysr@777:              "SLT is a JavaThread");
ysr@777:       // wait for msg buffer to become non-empty
ysr@777:       while (_buffer == empty) {
ysr@777:         _monitor.notify();
ysr@777:         _monitor.wait();
ysr@777:       }
ysr@777:       msg = _buffer;
ysr@777:     }
ysr@777:     switch(msg) {
ysr@777:       case acquirePLL: {
coleenp@4047:         InstanceRefKlass::acquire_pending_list_lock(&pll_basic_lock);
ysr@777:         debug_only(owned++;)
ysr@777:         break;
ysr@777:       }
ysr@777:       case releaseAndNotifyPLL: {
ysr@777:         assert(owned > 0, "Don't have PLL");
coleenp@4047:         InstanceRefKlass::release_and_notify_pending_list_lock(&pll_basic_lock);
ysr@777:         debug_only(owned--;)
ysr@777:         break;
ysr@777:       }
ysr@777:       case empty:
ysr@777:       default: {
ysr@777:         guarantee(false,"Unexpected message in _buffer");
ysr@777:         break;
ysr@777:       }
ysr@777:     }
ysr@777:     {
ysr@777:       MutexLocker x(&_monitor);
ysr@777:       // Since we are a JavaThread, we can't be here at a safepoint.
ysr@777:       assert(!SafepointSynchronize::is_at_safepoint(),
ysr@777:              "SLT is a JavaThread");
ysr@777:       _buffer = empty;
ysr@777:       _monitor.notify();
ysr@777:     }
ysr@777:   }
ysr@777:   assert(!_monitor.owned_by_self(), "Should unlock before exit.");
ysr@777: }
ysr@777: 
ysr@777: 
ysr@777: // ===== STS Access From Outside CGCT =====
ysr@777: 
ysr@777: void ConcurrentGCThread::stsYield(const char* id) {
ysr@777:   assert( Thread::current()->is_ConcurrentGC_thread(),
ysr@777:           "only a conc GC thread can call this" );
ysr@777:   _sts.yield(id);
ysr@777: }
ysr@777: 
ysr@777: bool ConcurrentGCThread::stsShouldYield() {
ysr@777:   assert( Thread::current()->is_ConcurrentGC_thread(),
ysr@777:           "only a conc GC thread can call this" );
ysr@777:   return _sts.should_yield();
ysr@777: }
ysr@777: 
ysr@777: void ConcurrentGCThread::stsJoin() {
ysr@777:   assert( Thread::current()->is_ConcurrentGC_thread(),
ysr@777:           "only a conc GC thread can call this" );
ysr@777:   _sts.join();
ysr@777: }
ysr@777: 
ysr@777: void ConcurrentGCThread::stsLeave() {
ysr@777:   assert( Thread::current()->is_ConcurrentGC_thread(),
ysr@777:           "only a conc GC thread can call this" );
ysr@777:   _sts.leave();
ysr@777: }