truffle: src/share/vm/runtime/thread.cpp comparison

comparison src/share/vm/runtime/thread.cpp @ 0:a61af66fc99e jdk7-b24

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author	duke
date	Sat, 01 Dec 2007 00:00:00 +0000
parents
children	c7d713375c94 31000d79ec71 5a76ab815e34

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--1:000000000000
+:a61af66fc99e
+/*
+* Copyright 1997-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+* CA 95054 USA or visit www.sun.com if you need additional information or
+* have any questions.
+*
+*/
+# include "incls/_precompiled.incl"
+# include "incls/_thread.cpp.incl"
+#ifdef DTRACE_ENABLED
+// Only bother with this argument setup if dtrace is available
+HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
+HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
+HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
+intptr_t, intptr_t, bool);
+HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
+intptr_t, intptr_t, bool);
+#define DTRACE_THREAD_PROBE(probe, javathread)                             \
+{                                                                        \
+ResourceMark rm(this);                                                 \
+int len = 0;                                                           \
+const char* name = (javathread)->get_thread_name();                    \
+len = strlen(name);                                                    \
+HS_DTRACE_PROBE5(hotspot, thread__##probe,                             \
+name, len,                                                           \
+java_lang_Thread::thread_id((javathread)->threadObj()),              \
+(javathread)->osthread()->thread_id(),                               \
+java_lang_Thread::is_daemon((javathread)->threadObj()));             \
+}
+#else //  ndef DTRACE_ENABLED
+#define DTRACE_THREAD_PROBE(probe, javathread)
+#endif // ndef DTRACE_ENABLED
+// Class hierarchy
+// - Thread
+//   - VMThread
+//   - WatcherThread
+//   - ConcurrentMarkSweepThread
+//   - JavaThread
+//     - CompilerThread
+// ======= Thread ========
+// Support for forcing alignment of thread objects for biased locking
+void* Thread::operator new(size_t size) {
+if (UseBiasedLocking) {
+const int alignment = markOopDesc::biased_lock_alignment;
+size_t aligned_size = size + (alignment - sizeof(intptr_t));
+void* real_malloc_addr = CHeapObj::operator new(aligned_size);
+void* aligned_addr     = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
+assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
+((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
+"JavaThread alignment code overflowed allocated storage");
+if (TraceBiasedLocking) {
+if (aligned_addr != real_malloc_addr)
+tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
+real_malloc_addr, aligned_addr);
+}
+((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
+return aligned_addr;
+} else {
+return CHeapObj::operator new(size);
+}
+}
+void Thread::operator delete(void* p) {
+if (UseBiasedLocking) {
+void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
+CHeapObj::operator delete(real_malloc_addr);
+} else {
+CHeapObj::operator delete(p);
+}
+}
+// Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
+// JavaThread
+Thread::Thread() {
+// stack
+_stack_base   = NULL;
+_stack_size   = 0;
+_self_raw_id  = 0;
+_lgrp_id      = -1;
+_osthread     = NULL;
+// allocated data structures
+set_resource_area(new ResourceArea());
+set_handle_area(new HandleArea(NULL));
+set_active_handles(NULL);
+set_free_handle_block(NULL);
+set_last_handle_mark(NULL);
+set_osthread(NULL);
+// This initial value ==> never claimed.
+_oops_do_parity = 0;
+// the handle mark links itself to last_handle_mark
+new HandleMark(this);
+// plain initialization
+debug_only(_owned_locks = NULL;)
+debug_only(_allow_allocation_count = 0;)
+NOT_PRODUCT(_allow_safepoint_count = 0;)
+CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
+_highest_lock = NULL;
+_jvmti_env_iteration_count = 0;
+_vm_operation_started_count = 0;
+_vm_operation_completed_count = 0;
+_current_pending_monitor = NULL;
+_current_pending_monitor_is_from_java = true;
+_current_waiting_monitor = NULL;
+_num_nested_signal = 0;
+omFreeList = NULL ;
+omFreeCount = 0 ;
+omFreeProvision = 32 ;
+_SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
+_suspend_flags = 0;
+// thread-specific hashCode stream generator state - Marsaglia shift-xor form
+_hashStateX = os::random() ;
+_hashStateY = 842502087 ;
+_hashStateZ = 0x8767 ;    // (int)(3579807591LL & 0xffff) ;
+_hashStateW = 273326509 ;
+_OnTrap   = 0 ;
+_schedctl = NULL ;
+_Stalled  = 0 ;
+_TypeTag  = 0x2BAD ;
+// Many of the following fields are effectively final - immutable
+// Note that nascent threads can't use the Native Monitor-Mutex
+// construct until the _MutexEvent is initialized ...
+// CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
+// we might instead use a stack of ParkEvents that we could provision on-demand.
+// The stack would act as a cache to avoid calls to ParkEvent::Allocate()
+// and ::Release()
+_ParkEvent   = ParkEvent::Allocate (this) ;
+_SleepEvent  = ParkEvent::Allocate (this) ;
+_MutexEvent  = ParkEvent::Allocate (this) ;
+_MuxEvent    = ParkEvent::Allocate (this) ;
+#ifdef CHECK_UNHANDLED_OOPS
+if (CheckUnhandledOops) {
+_unhandled_oops = new UnhandledOops(this);
+}
+#endif // CHECK_UNHANDLED_OOPS
+#ifdef ASSERT
+if (UseBiasedLocking) {
+assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
+assert(this == _real_malloc_address ||
+this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
+"bug in forced alignment of thread objects");
+}
+#endif /* ASSERT */
+}
+void Thread::initialize_thread_local_storage() {
+// Note: Make sure this method only calls
+// non-blocking operations. Otherwise, it might not work
+// with the thread-startup/safepoint interaction.
+// During Java thread startup, safepoint code should allow this
+// method to complete because it may need to allocate memory to
+// store information for the new thread.
+// initialize structure dependent on thread local storage
+ThreadLocalStorage::set_thread(this);
+// set up any platform-specific state.
+os::initialize_thread();
+}
+void Thread::record_stack_base_and_size() {
+set_stack_base(os::current_stack_base());
+set_stack_size(os::current_stack_size());
+}
+Thread::~Thread() {
+// Reclaim the objectmonitors from the omFreeList of the moribund thread.
+ObjectSynchronizer::omFlush (this) ;
+// deallocate data structures
+delete resource_area();
+// since the handle marks are using the handle area, we have to deallocated the root
+// handle mark before deallocating the thread's handle area,
+assert(last_handle_mark() != NULL, "check we have an element");
+delete last_handle_mark();
+assert(last_handle_mark() == NULL, "check we have reached the end");
+// It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
+// We NULL out the fields for good hygiene.
+ParkEvent::Release (_ParkEvent)   ; _ParkEvent   = NULL ;
+ParkEvent::Release (_SleepEvent)  ; _SleepEvent  = NULL ;
+ParkEvent::Release (_MutexEvent)  ; _MutexEvent  = NULL ;
+ParkEvent::Release (_MuxEvent)    ; _MuxEvent    = NULL ;
+delete handle_area();
+// osthread() can be NULL, if creation of thread failed.
+if (osthread() != NULL) os::free_thread(osthread());
+delete _SR_lock;
+// clear thread local storage if the Thread is deleting itself
+if (this == Thread::current()) {
+ThreadLocalStorage::set_thread(NULL);
+} else {
+// In the case where we're not the current thread, invalidate all the
+// caches in case some code tries to get the current thread or the
+// thread that was destroyed, and gets stale information.
+ThreadLocalStorage::invalidate_all();
+}
+CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
+}
+// NOTE: dummy function for assertion purpose.
+void Thread::run() {
+ShouldNotReachHere();
+}
+#ifdef ASSERT
+// Private method to check for dangling thread pointer
+void check_for_dangling_thread_pointer(Thread *thread) {
+assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
+"possibility of dangling Thread pointer");
+}
+#endif
+#ifndef PRODUCT
+// Tracing method for basic thread operations
+void Thread::trace(const char* msg, const Thread* const thread) {
+if (!TraceThreadEvents) return;
+ResourceMark rm;
+ThreadCritical tc;
+const char *name = "non-Java thread";
+int prio = -1;
+if (thread->is_Java_thread()
+&& !thread->is_Compiler_thread()) {
+// The Threads_lock must be held to get information about
+// this thread but may not be in some situations when
+// tracing  thread events.
+bool release_Threads_lock = false;
+if (!Threads_lock->owned_by_self()) {
+Threads_lock->lock();
+release_Threads_lock = true;
+}
+JavaThread* jt = (JavaThread *)thread;
+name = (char *)jt->get_thread_name();
+oop thread_oop = jt->threadObj();
+if (thread_oop != NULL) {
+prio = java_lang_Thread::priority(thread_oop);
+}
+if (release_Threads_lock) {
+Threads_lock->unlock();
+}
+}
+tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
+}
+#endif
+ThreadPriority Thread::get_priority(const Thread* const thread) {
+trace("get priority", thread);
+ThreadPriority priority;
+// Can return an error!
+(void)os::get_priority(thread, priority);
+assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
+return priority;
+}
+void Thread::set_priority(Thread* thread, ThreadPriority priority) {
+trace("set priority", thread);
+debug_only(check_for_dangling_thread_pointer(thread);)
+// Can return an error!
+(void)os::set_priority(thread, priority);
+}
+void Thread::start(Thread* thread) {
+trace("start", thread);
+// Start is different from resume in that its safety is guaranteed by context or
+// being called from a Java method synchronized on the Thread object.
+if (!DisableStartThread) {
+if (thread->is_Java_thread()) {
+// Initialize the thread state to RUNNABLE before starting this thread.
+// Can not set it after the thread started because we do not know the
+// exact thread state at that time. It could be in MONITOR_WAIT or
+// in SLEEPING or some other state.
+java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
+java_lang_Thread::RUNNABLE);
+}
+os::start_thread(thread);
+}
+}
+// Enqueue a VM_Operation to do the job for us - sometime later
+void Thread::send_async_exception(oop java_thread, oop java_throwable) {
+VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
+VMThread::execute(vm_stop);
+}
+//
+// Check if an external suspend request has completed (or has been
+// cancelled). Returns true if the thread is externally suspended and
+// false otherwise.
+//
+// The bits parameter returns information about the code path through
+// the routine. Useful for debugging:
+//
+// set in is_ext_suspend_completed():
+// 0x00000001 - routine was entered
+// 0x00000010 - routine return false at end
+// 0x00000100 - thread exited (return false)
+// 0x00000200 - suspend request cancelled (return false)
+// 0x00000400 - thread suspended (return true)
+// 0x00001000 - thread is in a suspend equivalent state (return true)
+// 0x00002000 - thread is native and walkable (return true)
+// 0x00004000 - thread is native_trans and walkable (needed retry)
+//
+// set in wait_for_ext_suspend_completion():
+// 0x00010000 - routine was entered
+// 0x00020000 - suspend request cancelled before loop (return false)
+// 0x00040000 - thread suspended before loop (return true)
+// 0x00080000 - suspend request cancelled in loop (return false)
+// 0x00100000 - thread suspended in loop (return true)
+// 0x00200000 - suspend not completed during retry loop (return false)
+//
+// Helper class for tracing suspend wait debug bits.
+//
+// 0x00000100 indicates that the target thread exited before it could
+// self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
+// 0x00080000 each indicate a cancelled suspend request so they don't
+// count as wait failures either.
+#define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
+class TraceSuspendDebugBits : public StackObj {
+private:
+JavaThread * jt;
+bool         is_wait;
+bool         called_by_wait;  // meaningful when !is_wait
+uint32_t *   bits;
+public:
+TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
+uint32_t *_bits) {
+jt             = _jt;
+is_wait        = _is_wait;
+called_by_wait = _called_by_wait;
+bits           = _bits;
+}
+~TraceSuspendDebugBits() {
+if (!is_wait) {
+#if 1
+// By default, don't trace bits for is_ext_suspend_completed() calls.
+// That trace is very chatty.
+return;
+#else
+if (!called_by_wait) {
+// If tracing for is_ext_suspend_completed() is enabled, then only
+// trace calls to it from wait_for_ext_suspend_completion()
+return;
+}
+#endif
+}
+if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
+if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
+MutexLocker ml(Threads_lock);  // needed for get_thread_name()
+ResourceMark rm;
+tty->print_cr(
+"Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
+jt->get_thread_name(), *bits);
+guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
+}
+}
+}
+};
+#undef DEBUG_FALSE_BITS
+bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
+TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
+bool did_trans_retry = false;  // only do thread_in_native_trans retry once
+bool do_trans_retry;           // flag to force the retry
+*bits |= 0x00000001;
+do {
+do_trans_retry = false;
+if (is_exiting()) {
+// Thread is in the process of exiting. This is always checked
+// first to reduce the risk of dereferencing a freed JavaThread.
+*bits |= 0x00000100;
+return false;
+}
+if (!is_external_suspend()) {
+// Suspend request is cancelled. This is always checked before
+// is_ext_suspended() to reduce the risk of a rogue resume
+// confusing the thread that made the suspend request.
+*bits |= 0x00000200;
+return false;
+}
+if (is_ext_suspended()) {
+// thread is suspended
+*bits |= 0x00000400;
+return true;
+}
+// Now that we no longer do hard suspends of threads running
+// native code, the target thread can be changing thread state
+// while we are in this routine:
+//
+//   _thread_in_native -> _thread_in_native_trans -> _thread_blocked
+//
+// We save a copy of the thread state as observed at this moment
+// and make our decision about suspend completeness based on the
+// copy. This closes the race where the thread state is seen as
+// _thread_in_native_trans in the if-thread_blocked check, but is
+// seen as _thread_blocked in if-thread_in_native_trans check.
+JavaThreadState save_state = thread_state();
+if (save_state == _thread_blocked && is_suspend_equivalent()) {
+// If the thread's state is _thread_blocked and this blocking
+// condition is known to be equivalent to a suspend, then we can
+// consider the thread to be externally suspended. This means that
+// the code that sets _thread_blocked has been modified to do
+// self-suspension if the blocking condition releases. We also
+// used to check for CONDVAR_WAIT here, but that is now covered by
+// the _thread_blocked with self-suspension check.
+//
+// Return true since we wouldn't be here unless there was still an
+// external suspend request.
+*bits |= 0x00001000;
+return true;
+} else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
+// Threads running native code will self-suspend on native==>VM/Java
+// transitions. If its stack is walkable (should always be the case
+// unless this function is called before the actual java_suspend()
+// call), then the wait is done.
+*bits |= 0x00002000;
+return true;
+} else if (!called_by_wait && !did_trans_retry &&
+save_state == _thread_in_native_trans &&
+frame_anchor()->walkable()) {
+// The thread is transitioning from thread_in_native to another
+// thread state. check_safepoint_and_suspend_for_native_trans()
+// will force the thread to self-suspend. If it hasn't gotten
+// there yet we may have caught the thread in-between the native
+// code check above and the self-suspend. Lucky us. If we were
+// called by wait_for_ext_suspend_completion(), then it
+// will be doing the retries so we don't have to.
+//
+// Since we use the saved thread state in the if-statement above,
+// there is a chance that the thread has already transitioned to
+// _thread_blocked by the time we get here. In that case, we will
+// make a single unnecessary pass through the logic below. This
+// doesn't hurt anything since we still do the trans retry.
+*bits |= 0x00004000;
+// Once the thread leaves thread_in_native_trans for another
+// thread state, we break out of this retry loop. We shouldn't
+// need this flag to prevent us from getting back here, but
+// sometimes paranoia is good.
+did_trans_retry = true;
+// We wait for the thread to transition to a more usable state.
+for (int i = 1; i <= SuspendRetryCount; i++) {
+// We used to do an "os::yield_all(i)" call here with the intention
+// that yielding would increase on each retry. However, the parameter
+// is ignored on Linux which means the yield didn't scale up. Waiting
+// on the SR_lock below provides a much more predictable scale up for
+// the delay. It also provides a simple/direct point to check for any
+// safepoint requests from the VMThread
+// temporarily drops SR_lock while doing wait with safepoint check
+// (if we're a JavaThread - the WatcherThread can also call this)
+// and increase delay with each retry
+SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
+// check the actual thread state instead of what we saved above
+if (thread_state() != _thread_in_native_trans) {
+// the thread has transitioned to another thread state so
+// try all the checks (except this one) one more time.
+do_trans_retry = true;
+break;
+}
+} // end retry loop
+}
+} while (do_trans_retry);
+*bits |= 0x00000010;
+return false;
+}
+//
+// Wait for an external suspend request to complete (or be cancelled).
+// Returns true if the thread is externally suspended and false otherwise.
+//
+bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
+uint32_t *bits) {
+TraceSuspendDebugBits tsdb(this, true /* is_wait */,
+false /* !called_by_wait */, bits);
+// local flag copies to minimize SR_lock hold time
+bool is_suspended;
+bool pending;
+uint32_t reset_bits;
+// set a marker so is_ext_suspend_completed() knows we are the caller
+*bits |= 0x00010000;
+// We use reset_bits to reinitialize the bits value at the top of
+// each retry loop. This allows the caller to make use of any
+// unused bits for their own marking purposes.
+reset_bits = *bits;
+{
+MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
+is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
+delay, bits);
+pending = is_external_suspend();
+}
+// must release SR_lock to allow suspension to complete
+if (!pending) {
+// A cancelled suspend request is the only false return from
+// is_ext_suspend_completed() that keeps us from entering the
+// retry loop.
+*bits |= 0x00020000;
+return false;
+}
+if (is_suspended) {
+*bits |= 0x00040000;
+return true;
+}
+for (int i = 1; i <= retries; i++) {
+*bits = reset_bits;  // reinit to only track last retry
+// We used to do an "os::yield_all(i)" call here with the intention
+// that yielding would increase on each retry. However, the parameter
+// is ignored on Linux which means the yield didn't scale up. Waiting
+// on the SR_lock below provides a much more predictable scale up for
+// the delay. It also provides a simple/direct point to check for any
+// safepoint requests from the VMThread
+{
+MutexLocker ml(SR_lock());
+// wait with safepoint check (if we're a JavaThread - the WatcherThread
+// can also call this)  and increase delay with each retry
+SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
+is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
+delay, bits);
+// It is possible for the external suspend request to be cancelled
+// (by a resume) before the actual suspend operation is completed.
+// Refresh our local copy to see if we still need to wait.
+pending = is_external_suspend();
+}
+if (!pending) {
+// A cancelled suspend request is the only false return from
+// is_ext_suspend_completed() that keeps us from staying in the
+// retry loop.
+*bits |= 0x00080000;
+return false;
+}
+if (is_suspended) {
+*bits |= 0x00100000;
+return true;
+}
+} // end retry loop
+// thread did not suspend after all our retries
+*bits |= 0x00200000;
+return false;
+}
+#ifndef PRODUCT
+void JavaThread::record_jump(address target, address instr, const char* file, int line) {
+// This should not need to be atomic as the only way for simultaneous
+// updates is via interrupts. Even then this should be rare or non-existant
+// and we don't care that much anyway.
+int index = _jmp_ring_index;
+_jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
+_jmp_ring[index]._target = (intptr_t) target;
+_jmp_ring[index]._instruction = (intptr_t) instr;
+_jmp_ring[index]._file = file;
+_jmp_ring[index]._line = line;
+}
+#endif /* PRODUCT */
+// Called by flat profiler
+// Callers have already called wait_for_ext_suspend_completion
+// The assertion for that is currently too complex to put here:
+bool JavaThread::profile_last_Java_frame(frame* _fr) {
+bool gotframe = false;
+// self suspension saves needed state.
+if (has_last_Java_frame() && _anchor.walkable()) {
+*_fr = pd_last_frame();
+gotframe = true;
+}
+return gotframe;
+}
+void Thread::interrupt(Thread* thread) {
+trace("interrupt", thread);
+debug_only(check_for_dangling_thread_pointer(thread);)
+os::interrupt(thread);
+}
+bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
+trace("is_interrupted", thread);
+debug_only(check_for_dangling_thread_pointer(thread);)
+// Note:  If clear_interrupted==false, this simply fetches and
+// returns the value of the field osthread()->interrupted().
+return os::is_interrupted(thread, clear_interrupted);
+}
+// GC Support
+bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
+jint thread_parity = _oops_do_parity;
+if (thread_parity != strong_roots_parity) {
+jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
+if (res == thread_parity) return true;
+else {
+guarantee(res == strong_roots_parity, "Or else what?");
+assert(SharedHeap::heap()->n_par_threads() > 0,
+"Should only fail when parallel.");
+return false;
+}
+}
+assert(SharedHeap::heap()->n_par_threads() > 0,
+"Should only fail when parallel.");
+return false;
+}
+void Thread::oops_do(OopClosure* f) {
+active_handles()->oops_do(f);
+// Do oop for ThreadShadow
+f->do_oop((oop*)&_pending_exception);
+handle_area()->oops_do(f);
+}
+void Thread::nmethods_do() {
+}
+void Thread::print_on(outputStream* st) const {
+// get_priority assumes osthread initialized
+if (osthread() != NULL) {
+st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
+osthread()->print_on(st);
+}
+debug_only(if (WizardMode) print_owned_locks_on(st);)
+}
+// Thread::print_on_error() is called by fatal error handler. Don't use
+// any lock or allocate memory.
+void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
+if      (is_VM_thread())                  st->print("VMThread");
+else if (is_Compiler_thread())            st->print("CompilerThread");
+else if (is_Java_thread())                st->print("JavaThread");
+else if (is_GC_task_thread())             st->print("GCTaskThread");
+else if (is_Watcher_thread())             st->print("WatcherThread");
+else if (is_ConcurrentGC_thread())        st->print("ConcurrentGCThread");
+else st->print("Thread");
+st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
+_stack_base - _stack_size, _stack_base);
+if (osthread()) {
+st->print(" [id=%d]", osthread()->thread_id());
+}
+}
+#ifdef ASSERT
+void Thread::print_owned_locks_on(outputStream* st) const {
+Monitor *cur = _owned_locks;
+if (cur == NULL) {
+st->print(" (no locks) ");
+} else {
+st->print_cr(" Locks owned:");
+while(cur) {
+cur->print_on(st);
+cur = cur->next();
+}
+}
+}
+static int ref_use_count  = 0;
+bool Thread::owns_locks_but_compiled_lock() const {
+for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
+if (cur != Compile_lock) return true;
+}
+return false;
+}
+#endif
+#ifndef PRODUCT
+// The flag: potential_vm_operation notifies if this particular safepoint state could potential
+// invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
+// no threads which allow_vm_block's are held
+void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
+// Check if current thread is allowed to block at a safepoint
+if (!(_allow_safepoint_count == 0))
+fatal("Possible safepoint reached by thread that does not allow it");
+if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
+fatal("LEAF method calling lock?");
+}
+#ifdef ASSERT
+if (potential_vm_operation && is_Java_thread()
+&& !Universe::is_bootstrapping()) {
+// Make sure we do not hold any locks that the VM thread also uses.
+// This could potentially lead to deadlocks
+for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
+// Threads_lock is special, since the safepoint synchronization will not start before this is
+// acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
+// since it is used to transfer control between JavaThreads and the VMThread
+// Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
+if ( (cur->allow_vm_block() &&
+cur != Threads_lock &&
+cur != Compile_lock &&               // Temporary: should not be necessary when we get spearate compilation
+cur != VMOperationRequest_lock &&
+cur != VMOperationQueue_lock) ||
+cur->rank() == Mutex::special) {
+warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
+}
+}
+}
+if (GCALotAtAllSafepoints) {
+// We could enter a safepoint here and thus have a gc
+InterfaceSupport::check_gc_alot();
+}
+#endif
+}
+#endif
+bool Thread::lock_is_in_stack(address adr) const {
+assert(Thread::current() == this, "lock_is_in_stack can only be called from current thread");
+// High limit: highest_lock is set during thread execution
+// Low  limit: address of the local variable dummy, rounded to 4K boundary.
+// (The rounding helps finding threads in unsafe mode, even if the particular stack
+// frame has been popped already.  Correct as long as stacks are at least 4K long and aligned.)
+address end = os::current_stack_pointer();
+if (_highest_lock >= adr && adr >= end) return true;
+return false;
+}
+bool Thread::is_in_stack(address adr) const {
+assert(Thread::current() == this, "is_in_stack can only be called from current thread");
+address end = os::current_stack_pointer();
+if (stack_base() >= adr && adr >= end) return true;
+return false;
+}
+// We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
+// However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
+// used for compilation in the future. If that change is made, the need for these methods
+// should be revisited, and they should be removed if possible.
+bool Thread::is_lock_owned(address adr) const {
+if (lock_is_in_stack(adr) ) return true;
+return false;
+}
+bool Thread::set_as_starting_thread() {
+// NOTE: this must be called inside the main thread.
+return os::create_main_thread((JavaThread*)this);
+}
+static void initialize_class(symbolHandle class_name, TRAPS) {
+klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
+instanceKlass::cast(klass)->initialize(CHECK);
+}
+// Creates the initial ThreadGroup
+static Handle create_initial_thread_group(TRAPS) {
+klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_ThreadGroup(), true, CHECK_NH);
+instanceKlassHandle klass (THREAD, k);
+Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
+{
+JavaValue result(T_VOID);
+JavaCalls::call_special(&result,
+system_instance,
+klass,
+vmSymbolHandles::object_initializer_name(),
+vmSymbolHandles::void_method_signature(),
+CHECK_NH);
+}
+Universe::set_system_thread_group(system_instance());
+Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
+{
+JavaValue result(T_VOID);
+Handle string = java_lang_String::create_from_str("main", CHECK_NH);
+JavaCalls::call_special(&result,
+main_instance,
+klass,
+vmSymbolHandles::object_initializer_name(),
+vmSymbolHandles::threadgroup_string_void_signature(),
+system_instance,
+string,
+CHECK_NH);
+}
+return main_instance;
+}
+// Creates the initial Thread
+static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
+klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK_NULL);
+instanceKlassHandle klass (THREAD, k);
+instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
+java_lang_Thread::set_thread(thread_oop(), thread);
+java_lang_Thread::set_priority(thread_oop(), NormPriority);
+thread->set_threadObj(thread_oop());
+Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
+JavaValue result(T_VOID);
+JavaCalls::call_special(&result, thread_oop,
+klass,
+vmSymbolHandles::object_initializer_name(),
+vmSymbolHandles::threadgroup_string_void_signature(),
+thread_group,
+string,
+CHECK_NULL);
+return thread_oop();
+}
+static void call_initializeSystemClass(TRAPS) {
+klassOop k =  SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
+instanceKlassHandle klass (THREAD, k);
+JavaValue result(T_VOID);
+JavaCalls::call_static(&result, klass, vmSymbolHandles::initializeSystemClass_name(),
+vmSymbolHandles::void_method_signature(), CHECK);
+}
+static void reset_vm_info_property(TRAPS) {
+// the vm info string
+ResourceMark rm(THREAD);
+const char *vm_info = VM_Version::vm_info_string();
+// java.lang.System class
+klassOop k =  SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
+instanceKlassHandle klass (THREAD, k);
+// setProperty arguments
+Handle key_str    = java_lang_String::create_from_str("java.vm.info", CHECK);
+Handle value_str  = java_lang_String::create_from_str(vm_info, CHECK);
+// return value
+JavaValue r(T_OBJECT);
+// public static String setProperty(String key, String value);
+JavaCalls::call_static(&r,
+klass,
+vmSymbolHandles::setProperty_name(),
+vmSymbolHandles::string_string_string_signature(),
+key_str,
+value_str,
+CHECK);
+}
+void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
+assert(thread_group.not_null(), "thread group should be specified");
+assert(threadObj() == NULL, "should only create Java thread object once");
+klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK);
+instanceKlassHandle klass (THREAD, k);
+instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
+java_lang_Thread::set_thread(thread_oop(), this);
+java_lang_Thread::set_priority(thread_oop(), NormPriority);
+set_threadObj(thread_oop());
+JavaValue result(T_VOID);
+if (thread_name != NULL) {
+Handle name = java_lang_String::create_from_str(thread_name, CHECK);
+// Thread gets assigned specified name and null target
+JavaCalls::call_special(&result,
+thread_oop,
+klass,
+vmSymbolHandles::object_initializer_name(),
+vmSymbolHandles::threadgroup_string_void_signature(),
+thread_group, // Argument 1
+name,         // Argument 2
+THREAD);
+} else {
+// Thread gets assigned name "Thread-nnn" and null target
+// (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
+JavaCalls::call_special(&result,
+thread_oop,
+klass,
+vmSymbolHandles::object_initializer_name(),
+vmSymbolHandles::threadgroup_runnable_void_signature(),
+thread_group, // Argument 1
+Handle(),     // Argument 2
+THREAD);
+}
+if (daemon) {
+java_lang_Thread::set_daemon(thread_oop());
+}
+if (HAS_PENDING_EXCEPTION) {
+return;
+}
+KlassHandle group(this, SystemDictionary::threadGroup_klass());
+Handle threadObj(this, this->threadObj());
+JavaCalls::call_special(&result,
+thread_group,
+group,
+vmSymbolHandles::add_method_name(),
+vmSymbolHandles::thread_void_signature(),
+threadObj,          // Arg 1
+THREAD);
+}
+// NamedThread --  non-JavaThread subclasses with multiple
+// uniquely named instances should derive from this.
+NamedThread::NamedThread() : Thread() {
+_name = NULL;
+}
+NamedThread::~NamedThread() {
+if (_name != NULL) {
+FREE_C_HEAP_ARRAY(char, _name);
+_name = NULL;
+}
+}
+void NamedThread::set_name(const char* format, ...) {
+guarantee(_name == NULL, "Only get to set name once.");
+_name = NEW_C_HEAP_ARRAY(char, max_name_len);
+guarantee(_name != NULL, "alloc failure");
+va_list ap;
+va_start(ap, format);
+jio_vsnprintf(_name, max_name_len, format, ap);
+va_end(ap);
+}
+// ======= WatcherThread ========
+// The watcher thread exists to simulate timer interrupts.  It should
+// be replaced by an abstraction over whatever native support for
+// timer interrupts exists on the platform.
+WatcherThread* WatcherThread::_watcher_thread   = NULL;
+bool           WatcherThread::_should_terminate = false;
+WatcherThread::WatcherThread() : Thread() {
+assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
+if (os::create_thread(this, os::watcher_thread)) {
+_watcher_thread = this;
+// Set the watcher thread to the highest OS priority which should not be
+// used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
+// is created. The only normal thread using this priority is the reference
+// handler thread, which runs for very short intervals only.
+// If the VMThread's priority is not lower than the WatcherThread profiling
+// will be inaccurate.
+os::set_priority(this, MaxPriority);
+if (!DisableStartThread) {
+os::start_thread(this);
+}
+}
+}
+void WatcherThread::run() {
+assert(this == watcher_thread(), "just checking");
+this->record_stack_base_and_size();
+this->initialize_thread_local_storage();
+this->set_active_handles(JNIHandleBlock::allocate_block());
+while(!_should_terminate) {
+assert(watcher_thread() == Thread::current(),  "thread consistency check");
+assert(watcher_thread() == this,  "thread consistency check");
+// Calculate how long it'll be until the next PeriodicTask work
+// should be done, and sleep that amount of time.
+const size_t time_to_wait = PeriodicTask::time_to_wait();
+os::sleep(this, time_to_wait, false);
+if (is_error_reported()) {
+// A fatal error has happened, the error handler(VMError::report_and_die)
+// should abort JVM after creating an error log file. However in some
+// rare cases, the error handler itself might deadlock. Here we try to
+// kill JVM if the fatal error handler fails to abort in 2 minutes.
+//
+// This code is in WatcherThread because WatcherThread wakes up
+// periodically so the fatal error handler doesn't need to do anything;
+// also because the WatcherThread is less likely to crash than other
+// threads.
+for (;;) {
+if (!ShowMessageBoxOnError
+&& (OnError == NULL || OnError[0] == '\0')
+&& Arguments::abort_hook() == NULL) {
+os::sleep(this, 2 * 60 * 1000, false);
+fdStream err(defaultStream::output_fd());
+err.print_raw_cr("# [ timer expired, abort... ]");
+// skip atexit/vm_exit/vm_abort hooks
+os::die();
+}
+// Wake up 5 seconds later, the fatal handler may reset OnError or
+// ShowMessageBoxOnError when it is ready to abort.
+os::sleep(this, 5 * 1000, false);
+}
+}
+PeriodicTask::real_time_tick(time_to_wait);
+// If we have no more tasks left due to dynamic disenrollment,
+// shut down the thread since we don't currently support dynamic enrollment
+if (PeriodicTask::num_tasks() == 0) {
+_should_terminate = true;
+}
+}
+// Signal that it is terminated
+{
+MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
+_watcher_thread = NULL;
+Terminator_lock->notify();
+}
+// Thread destructor usually does this..
+ThreadLocalStorage::set_thread(NULL);
+}
+void WatcherThread::start() {
+if (watcher_thread() == NULL) {
+_should_terminate = false;
+// Create the single instance of WatcherThread
+new WatcherThread();
+}
+}
+void WatcherThread::stop() {
+// it is ok to take late safepoints here, if needed
+MutexLocker mu(Terminator_lock);
+_should_terminate = true;
+while(watcher_thread() != NULL) {
+// This wait should make safepoint checks, wait without a timeout,
+// and wait as a suspend-equivalent condition.
+//
+// Note: If the FlatProfiler is running, then this thread is waiting
+// for the WatcherThread to terminate and the WatcherThread, via the
+// FlatProfiler task, is waiting for the external suspend request on
+// this thread to complete. wait_for_ext_suspend_completion() will
+// eventually timeout, but that takes time. Making this wait a
+// suspend-equivalent condition solves that timeout problem.
+//
+Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
+Mutex::_as_suspend_equivalent_flag);
+}
+}
+void WatcherThread::print_on(outputStream* st) const {
+st->print("\"%s\" ", name());
+Thread::print_on(st);
+st->cr();
+}
+// ======= JavaThread ========
+// A JavaThread is a normal Java thread
+void JavaThread::initialize() {
+// Initialize fields
+set_saved_exception_pc(NULL);
+set_threadObj(NULL);
+_anchor.clear();
+set_entry_point(NULL);
+set_jni_functions(jni_functions());
+set_callee_target(NULL);
+set_vm_result(NULL);
+set_vm_result_2(NULL);
+set_vframe_array_head(NULL);
+set_vframe_array_last(NULL);
+set_deferred_locals(NULL);
+set_deopt_mark(NULL);
+clear_must_deopt_id();
+set_monitor_chunks(NULL);
+set_next(NULL);
+set_thread_state(_thread_new);
+_terminated = _not_terminated;
+_privileged_stack_top = NULL;
+_array_for_gc = NULL;
+_suspend_equivalent = false;
+_in_deopt_handler = 0;
+_doing_unsafe_access = false;
+_stack_guard_state = stack_guard_unused;
+_exception_oop = NULL;
+_exception_pc  = 0;
+_exception_handler_pc = 0;
+_exception_stack_size = 0;
+_jvmti_thread_state= NULL;
+_jvmti_get_loaded_classes_closure = NULL;
+_interp_only_mode    = 0;
+_special_runtime_exit_condition = _no_async_condition;
+_pending_async_exception = NULL;
+_is_compiling = false;
+_thread_stat = NULL;
+_thread_stat = new ThreadStatistics();
+_blocked_on_compilation = false;
+_jni_active_critical = 0;
+_do_not_unlock_if_synchronized = false;
+_cached_monitor_info = NULL;
+_parker = Parker::Allocate(this) ;
+#ifndef PRODUCT
+_jmp_ring_index = 0;
+for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
+record_jump(NULL, NULL, NULL, 0);
+}
+#endif /* PRODUCT */
+set_thread_profiler(NULL);
+if (FlatProfiler::is_active()) {
+// This is where we would decide to either give each thread it's own profiler
+// or use one global one from FlatProfiler,
+// or up to some count of the number of profiled threads, etc.
+ThreadProfiler* pp = new ThreadProfiler();
+pp->engage();
+set_thread_profiler(pp);
+}
+// Setup safepoint state info for this thread
+ThreadSafepointState::create(this);
+debug_only(_java_call_counter = 0);
+// JVMTI PopFrame support
+_popframe_condition = popframe_inactive;
+_popframe_preserved_args = NULL;
+_popframe_preserved_args_size = 0;
+pd_initialize();
+}
+JavaThread::JavaThread(bool is_attaching) : Thread() {
+initialize();
+_is_attaching = is_attaching;
+}
+bool JavaThread::reguard_stack(address cur_sp) {
+if (_stack_guard_state != stack_guard_yellow_disabled) {
+return true; // Stack already guarded or guard pages not needed.
+}
+if (register_stack_overflow()) {
+// For those architectures which have separate register and
+// memory stacks, we must check the register stack to see if
+// it has overflowed.
+return false;
+}
+// Java code never executes within the yellow zone: the latter is only
+// there to provoke an exception during stack banging.  If java code
+// is executing there, either StackShadowPages should be larger, or
+// some exception code in c1, c2 or the interpreter isn't unwinding
+// when it should.
+guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
+enable_stack_yellow_zone();
+return true;
+}
+bool JavaThread::reguard_stack(void) {
+return reguard_stack(os::current_stack_pointer());
+}
+void JavaThread::block_if_vm_exited() {
+if (_terminated == _vm_exited) {
+// _vm_exited is set at safepoint, and Threads_lock is never released
+// we will block here forever
+Threads_lock->lock_without_safepoint_check();
+ShouldNotReachHere();
+}
+}
+// Remove this ifdef when C1 is ported to the compiler interface.
+static void compiler_thread_entry(JavaThread* thread, TRAPS);
+JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : Thread() {
+if (TraceThreadEvents) {
+tty->print_cr("creating thread %p", this);
+}
+initialize();
+_is_attaching = false;
+set_entry_point(entry_point);
+// Create the native thread itself.
+// %note runtime_23
+os::ThreadType thr_type = os::java_thread;
+thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
+os::java_thread;
+os::create_thread(this, thr_type, stack_sz);
+// The _osthread may be NULL here because we ran out of memory (too many threads active).
+// We need to throw and OutOfMemoryError - however we cannot do this here because the caller
+// may hold a lock and all locks must be unlocked before throwing the exception (throwing
+// the exception consists of creating the exception object & initializing it, initialization
+// will leave the VM via a JavaCall and then all locks must be unlocked).
+//
+// The thread is still suspended when we reach here. Thread must be explicit started
+// by creator! Furthermore, the thread must also explicitly be added to the Threads list
+// by calling Threads:add. The reason why this is not done here, is because the thread
+// object must be fully initialized (take a look at JVM_Start)
+}
+JavaThread::~JavaThread() {
+if (TraceThreadEvents) {
+tty->print_cr("terminate thread %p", this);
+}
+// JSR166 -- return the parker to the free list
+Parker::Release(_parker);
+_parker = NULL ;
+// Free any remaining  previous UnrollBlock
+vframeArray* old_array = vframe_array_last();
+if (old_array != NULL) {
+Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
+old_array->set_unroll_block(NULL);
+delete old_info;
+delete old_array;
+}
+GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
+if (deferred != NULL) {
+// This can only happen if thread is destroyed before deoptimization occurs.
+assert(deferred->length() != 0, "empty array!");
+do {
+jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
+deferred->remove_at(0);
+// individual jvmtiDeferredLocalVariableSet are CHeapObj's
+delete dlv;
+} while (deferred->length() != 0);
+delete deferred;
+}
+// All Java related clean up happens in exit
+ThreadSafepointState::destroy(this);
+if (_thread_profiler != NULL) delete _thread_profiler;
+if (_thread_stat != NULL) delete _thread_stat;
+if (jvmti_thread_state() != NULL) {
+JvmtiExport::cleanup_thread(this);
+}
+}
+// The first routine called by a new Java thread
+void JavaThread::run() {
+// initialize thread-local alloc buffer related fields
+this->initialize_tlab();
+// used to test validitity of stack trace backs
+this->record_base_of_stack_pointer();
+// Record real stack base and size.
+this->record_stack_base_and_size();
+// Initialize thread local storage; set before calling MutexLocker
+this->initialize_thread_local_storage();
+this->create_stack_guard_pages();
+// Thread is now sufficient initialized to be handled by the safepoint code as being
+// in the VM. Change thread state from _thread_new to _thread_in_vm
+ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
+assert(JavaThread::current() == this, "sanity check");
+assert(!Thread::current()->owns_locks(), "sanity check");
+DTRACE_THREAD_PROBE(start, this);
+// This operation might block. We call that after all safepoint checks for a new thread has
+// been completed.
+this->set_active_handles(JNIHandleBlock::allocate_block());
+if (JvmtiExport::should_post_thread_life()) {
+JvmtiExport::post_thread_start(this);
+}
+// We call another function to do the rest so we are sure that the stack addresses used
+// from there will be lower than the stack base just computed
+thread_main_inner();
+// Note, thread is no longer valid at this point!
+}
+void JavaThread::thread_main_inner() {
+assert(JavaThread::current() == this, "sanity check");
+assert(this->threadObj() != NULL, "just checking");
+// Execute thread entry point. If this thread is being asked to restart,
+// or has been stopped before starting, do not reexecute entry point.
+// Note: Due to JVM_StopThread we can have pending exceptions already!
+if (!this->has_pending_exception() && !java_lang_Thread::is_stillborn(this->threadObj())) {
+// enter the thread's entry point only if we have no pending exceptions
+HandleMark hm(this);
+this->entry_point()(this, this);
+}
+DTRACE_THREAD_PROBE(stop, this);
+this->exit(false);
+delete this;
+}
+static void ensure_join(JavaThread* thread) {
+// We do not need to grap the Threads_lock, since we are operating on ourself.
+Handle threadObj(thread, thread->threadObj());
+assert(threadObj.not_null(), "java thread object must exist");
+ObjectLocker lock(threadObj, thread);
+// Ignore pending exception (ThreadDeath), since we are exiting anyway
+thread->clear_pending_exception();
+// It is of profound importance that we set the stillborn bit and reset the thread object,
+// before we do the notify. Since, changing these two variable will make JVM_IsAlive return
+// false. So in case another thread is doing a join on this thread , it will detect that the thread
+// is dead when it gets notified.
+java_lang_Thread::set_stillborn(threadObj());
+// Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
+java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
+java_lang_Thread::set_thread(threadObj(), NULL);
+lock.notify_all(thread);
+// Ignore pending exception (ThreadDeath), since we are exiting anyway
+thread->clear_pending_exception();
+}
+// For any new cleanup additions, please check to see if they need to be applied to
+// cleanup_failed_attach_current_thread as well.
+void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
+assert(this == JavaThread::current(),  "thread consistency check");
+if (!InitializeJavaLangSystem) return;
+HandleMark hm(this);
+Handle uncaught_exception(this, this->pending_exception());
+this->clear_pending_exception();
+Handle threadObj(this, this->threadObj());
+assert(threadObj.not_null(), "Java thread object should be created");
+if (get_thread_profiler() != NULL) {
+get_thread_profiler()->disengage();
+ResourceMark rm;
+get_thread_profiler()->print(get_thread_name());
+}
+// FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
+{
+EXCEPTION_MARK;
+CLEAR_PENDING_EXCEPTION;
+}
+// FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
+// has to be fixed by a runtime query method
+if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
+// JSR-166: change call from from ThreadGroup.uncaughtException to
+// java.lang.Thread.dispatchUncaughtException
+if (uncaught_exception.not_null()) {
+Handle group(this, java_lang_Thread::threadGroup(threadObj()));
+Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT",
+(address)uncaught_exception(), (address)threadObj(), (address)group());
+{
+EXCEPTION_MARK;
+// Check if the method Thread.dispatchUncaughtException() exists. If so
+// call it.  Otherwise we have an older library without the JSR-166 changes,
+// so call ThreadGroup.uncaughtException()
+KlassHandle recvrKlass(THREAD, threadObj->klass());
+CallInfo callinfo;
+KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass());
+LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
+vmSymbolHandles::dispatchUncaughtException_name(),
+vmSymbolHandles::throwable_void_signature(),
+KlassHandle(), false, false, THREAD);
+CLEAR_PENDING_EXCEPTION;
+methodHandle method = callinfo.selected_method();
+if (method.not_null()) {
+JavaValue result(T_VOID);
+JavaCalls::call_virtual(&result,
+threadObj, thread_klass,
+vmSymbolHandles::dispatchUncaughtException_name(),
+vmSymbolHandles::throwable_void_signature(),
+uncaught_exception,
+THREAD);
+} else {
+KlassHandle thread_group(THREAD, SystemDictionary::threadGroup_klass());
+JavaValue result(T_VOID);
+JavaCalls::call_virtual(&result,
+group, thread_group,
+vmSymbolHandles::uncaughtException_name(),
+vmSymbolHandles::thread_throwable_void_signature(),
+threadObj,           // Arg 1
+uncaught_exception,  // Arg 2
+THREAD);
+}
+CLEAR_PENDING_EXCEPTION;
+}
+}
+// Call Thread.exit(). We try 3 times in case we got another Thread.stop during
+// the execution of the method. If that is not enough, then we don't really care. Thread.stop
+// is deprecated anyhow.
+{ int count = 3;
+while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
+EXCEPTION_MARK;
+JavaValue result(T_VOID);
+KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass());
+JavaCalls::call_virtual(&result,
+threadObj, thread_klass,
+vmSymbolHandles::exit_method_name(),
+vmSymbolHandles::void_method_signature(),
+THREAD);
+CLEAR_PENDING_EXCEPTION;
+}
+}
+// notify JVMTI
+if (JvmtiExport::should_post_thread_life()) {
+JvmtiExport::post_thread_end(this);
+}
+// We have notified the agents that we are exiting, before we go on,
+// we must check for a pending external suspend request and honor it
+// in order to not surprise the thread that made the suspend request.
+while (true) {
+{
+MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
+if (!is_external_suspend()) {
+set_terminated(_thread_exiting);
+ThreadService::current_thread_exiting(this);
+break;
+}
+// Implied else:
+// Things get a little tricky here. We have a pending external
+// suspend request, but we are holding the SR_lock so we
+// can't just self-suspend. So we temporarily drop the lock
+// and then self-suspend.
+}
+ThreadBlockInVM tbivm(this);
+java_suspend_self();
+// We're done with this suspend request, but we have to loop around
+// and check again. Eventually we will get SR_lock without a pending
+// external suspend request and will be able to mark ourselves as
+// exiting.
+}
+// no more external suspends are allowed at this point
+} else {
+// before_exit() has already posted JVMTI THREAD_END events
+}
+// Notify waiters on thread object. This has to be done after exit() is called
+// on the thread (if the thread is the last thread in a daemon ThreadGroup the
+// group should have the destroyed bit set before waiters are notified).
+ensure_join(this);
+assert(!this->has_pending_exception(), "ensure_join should have cleared");
+// 6282335 JNI DetachCurrentThread spec states that all Java monitors
+// held by this thread must be released.  A detach operation must only
+// get here if there are no Java frames on the stack.  Therefore, any
+// owned monitors at this point MUST be JNI-acquired monitors which are
+// pre-inflated and in the monitor cache.
+//
+// ensure_join() ignores IllegalThreadStateExceptions, and so does this.
+if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
+assert(!this->has_last_Java_frame(), "detaching with Java frames?");
+ObjectSynchronizer::release_monitors_owned_by_thread(this);
+assert(!this->has_pending_exception(), "release_monitors should have cleared");
+}
+// These things needs to be done while we are still a Java Thread. Make sure that thread
+// is in a consistent state, in case GC happens
+assert(_privileged_stack_top == NULL, "must be NULL when we get here");
+if (active_handles() != NULL) {
+JNIHandleBlock* block = active_handles();
+set_active_handles(NULL);
+JNIHandleBlock::release_block(block);
+}
+if (free_handle_block() != NULL) {
+JNIHandleBlock* block = free_handle_block();
+set_free_handle_block(NULL);
+JNIHandleBlock::release_block(block);
+}
+// These have to be removed while this is still a valid thread.
+remove_stack_guard_pages();
+if (UseTLAB) {
+tlab().make_parsable(true);  // retire TLAB
+}
+// Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
+Threads::remove(this);
+}
+void JavaThread::cleanup_failed_attach_current_thread() {
+if (get_thread_profiler() != NULL) {
+get_thread_profiler()->disengage();
+ResourceMark rm;
+get_thread_profiler()->print(get_thread_name());
+}
+if (active_handles() != NULL) {
+JNIHandleBlock* block = active_handles();
+set_active_handles(NULL);
+JNIHandleBlock::release_block(block);
+}
+if (free_handle_block() != NULL) {
+JNIHandleBlock* block = free_handle_block();
+set_free_handle_block(NULL);
+JNIHandleBlock::release_block(block);
+}
+if (UseTLAB) {
+tlab().make_parsable(true);  // retire TLAB, if any
+}
+Threads::remove(this);
+delete this;
+}
+JavaThread* JavaThread::active() {
+Thread* thread = ThreadLocalStorage::thread();
+assert(thread != NULL, "just checking");
+if (thread->is_Java_thread()) {
+return (JavaThread*) thread;
+} else {
+assert(thread->is_VM_thread(), "this must be a vm thread");
+VM_Operation* op = ((VMThread*) thread)->vm_operation();
+JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
+assert(ret->is_Java_thread(), "must be a Java thread");
+return ret;
+}
+}
+bool JavaThread::is_lock_owned(address adr) const {
+if (lock_is_in_stack(adr)) return true;
+for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
+if (chunk->contains(adr)) return true;
+}
+return false;
+}
+void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
+chunk->set_next(monitor_chunks());
+set_monitor_chunks(chunk);
+}
+void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
+guarantee(monitor_chunks() != NULL, "must be non empty");
+if (monitor_chunks() == chunk) {
+set_monitor_chunks(chunk->next());
+} else {
+MonitorChunk* prev = monitor_chunks();
+while (prev->next() != chunk) prev = prev->next();
+prev->set_next(chunk->next());
+}
+}
+// JVM support.
+// Note: this function shouldn't block if it's called in
+// _thread_in_native_trans state (such as from
+// check_special_condition_for_native_trans()).
+void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
+if (has_last_Java_frame() && has_async_condition()) {
+// If we are at a polling page safepoint (not a poll return)
+// then we must defer async exception because live registers
+// will be clobbered by the exception path. Poll return is
+// ok because the call we a returning from already collides
+// with exception handling registers and so there is no issue.
+// (The exception handling path kills call result registers but
+//  this is ok since the exception kills the result anyway).
+if (is_at_poll_safepoint()) {
+// if the code we are returning to has deoptimized we must defer
+// the exception otherwise live registers get clobbered on the
+// exception path before deoptimization is able to retrieve them.
+//
+RegisterMap map(this, false);
+frame caller_fr = last_frame().sender(&map);
+assert(caller_fr.is_compiled_frame(), "what?");
+if (caller_fr.is_deoptimized_frame()) {
+if (TraceExceptions) {
+ResourceMark rm;
+tty->print_cr("deferred async exception at compiled safepoint");
+}
+return;
+}
+}
+}
+JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
+if (condition == _no_async_condition) {
+// Conditions have changed since has_special_runtime_exit_condition()
+// was called:
+// - if we were here only because of an external suspend request,
+//   then that was taken care of above (or cancelled) so we are done
+// - if we were here because of another async request, then it has
+//   been cleared between the has_special_runtime_exit_condition()
+//   and now so again we are done
+return;
+}
+// Check for pending async. exception
+if (_pending_async_exception != NULL) {
+// Only overwrite an already pending exception, if it is not a threadDeath.
+if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::threaddeath_klass())) {
+// We cannot call Exceptions::_throw(...) here because we cannot block
+set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
+if (TraceExceptions) {
+ResourceMark rm;
+tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
+if (has_last_Java_frame() ) {
+frame f = last_frame();
+tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
+}
+tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
+}
+_pending_async_exception = NULL;
+clear_has_async_exception();
+}
+}
+if (check_unsafe_error &&
+condition == _async_unsafe_access_error && !has_pending_exception()) {
+condition = _no_async_condition;  // done
+switch (thread_state()) {
+case _thread_in_vm:
+{
+JavaThread* THREAD = this;
+THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
+}
+case _thread_in_native:
+{
+ThreadInVMfromNative tiv(this);
+JavaThread* THREAD = this;
+THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
+}
+case _thread_in_Java:
+{
+ThreadInVMfromJava tiv(this);
+JavaThread* THREAD = this;
+THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
+}
+default:
+ShouldNotReachHere();
+}
+}
+assert(condition == _no_async_condition || has_pending_exception() ||
+(!check_unsafe_error && condition == _async_unsafe_access_error),
+"must have handled the async condition, if no exception");
+}
+void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
+//
+// Check for pending external suspend. Internal suspend requests do
+// not use handle_special_runtime_exit_condition().
+// If JNIEnv proxies are allowed, don't self-suspend if the target
+// thread is not the current thread. In older versions of jdbx, jdbx
+// threads could call into the VM with another thread's JNIEnv so we
+// can be here operating on behalf of a suspended thread (4432884).
+bool do_self_suspend = is_external_suspend_with_lock();
+if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
+//
+// Because thread is external suspended the safepoint code will count
+// thread as at a safepoint. This can be odd because we can be here
+// as _thread_in_Java which would normally transition to _thread_blocked
+// at a safepoint. We would like to mark the thread as _thread_blocked
+// before calling java_suspend_self like all other callers of it but
+// we must then observe proper safepoint protocol. (We can't leave
+// _thread_blocked with a safepoint in progress). However we can be
+// here as _thread_in_native_trans so we can't use a normal transition
+// constructor/destructor pair because they assert on that type of
+// transition. We could do something like:
+//
+// JavaThreadState state = thread_state();
+// set_thread_state(_thread_in_vm);
+// {
+//   ThreadBlockInVM tbivm(this);
+//   java_suspend_self()
+// }
+// set_thread_state(_thread_in_vm_trans);
+// if (safepoint) block;
+// set_thread_state(state);
+//
+// but that is pretty messy. Instead we just go with the way the
+// code has worked before and note that this is the only path to
+// java_suspend_self that doesn't put the thread in _thread_blocked
+// mode.
+frame_anchor()->make_walkable(this);
+java_suspend_self();
+// We might be here for reasons in addition to the self-suspend request
+// so check for other async requests.
+}
+if (check_asyncs) {
+check_and_handle_async_exceptions();
+}
+}
+void JavaThread::send_thread_stop(oop java_throwable)  {
+assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
+assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
+assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
+// Do not throw asynchronous exceptions against the compiler thread
+// (the compiler thread should not be a Java thread -- fix in 1.4.2)
+if (is_Compiler_thread()) return;
+// This is a change from JDK 1.1, but JDK 1.2 will also do it:
+if (java_throwable->is_a(SystemDictionary::threaddeath_klass())) {
+java_lang_Thread::set_stillborn(threadObj());
+}
+{
+// Actually throw the Throwable against the target Thread - however
+// only if there is no thread death exception installed already.
+if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::threaddeath_klass())) {
+// If the topmost frame is a runtime stub, then we are calling into
+// OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
+// must deoptimize the caller before continuing, as the compiled  exception handler table
+// may not be valid
+if (has_last_Java_frame()) {
+frame f = last_frame();
+if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
+// BiasedLocking needs an updated RegisterMap for the revoke monitors pass
+RegisterMap reg_map(this, UseBiasedLocking);
+frame compiled_frame = f.sender(&reg_map);
+if (compiled_frame.can_be_deoptimized()) {
+Deoptimization::deoptimize(this, compiled_frame, &reg_map);
+}
+}
+}
+// Set async. pending exception in thread.
+set_pending_async_exception(java_throwable);
+if (TraceExceptions) {
+ResourceMark rm;
+tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
+}
+// for AbortVMOnException flag
+NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name()));
+}
+}
+// Interrupt thread so it will wake up from a potential wait()
+Thread::interrupt(this);
+}
+// External suspension mechanism.
+//
+// Tell the VM to suspend a thread when ever it knows that it does not hold on
+// to any VM_locks and it is at a transition
+// Self-suspension will happen on the transition out of the vm.
+// Catch "this" coming in from JNIEnv pointers when the thread has been freed
+//
+// Guarantees on return:
+//   + Target thread will not execute any new bytecode (that's why we need to
+//     force a safepoint)
+//   + Target thread will not enter any new monitors
+//
+void JavaThread::java_suspend() {
+{ MutexLocker mu(Threads_lock);
+if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
+return;
+}
+}
+{ MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
+if (!is_external_suspend()) {
+// a racing resume has cancelled us; bail out now
+return;
+}
+// suspend is done
+uint32_t debug_bits = 0;
+// Warning: is_ext_suspend_completed() may temporarily drop the
+// SR_lock to allow the thread to reach a stable thread state if
+// it is currently in a transient thread state.
+if (is_ext_suspend_completed(false /* !called_by_wait */,
+SuspendRetryDelay, &debug_bits) ) {
+return;
+}
+}
+VM_ForceSafepoint vm_suspend;
+VMThread::execute(&vm_suspend);
+}
+// Part II of external suspension.
+// A JavaThread self suspends when it detects a pending external suspend
+// request. This is usually on transitions. It is also done in places
+// where continuing to the next transition would surprise the caller,
+// e.g., monitor entry.
+//
+// Returns the number of times that the thread self-suspended.
+//
+// Note: DO NOT call java_suspend_self() when you just want to block current
+//       thread. java_suspend_self() is the second stage of cooperative
+//       suspension for external suspend requests and should only be used
+//       to complete an external suspend request.
+//
+int JavaThread::java_suspend_self() {
+int ret = 0;
+// we are in the process of exiting so don't suspend
+if (is_exiting()) {
+clear_external_suspend();
+return ret;
+}
+assert(_anchor.walkable() ||
+(is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
+"must have walkable stack");
+MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
+assert(!this->is_any_suspended(),
+"a thread trying to self-suspend should not already be suspended");
+if (this->is_suspend_equivalent()) {
+// If we are self-suspending as a result of the lifting of a
+// suspend equivalent condition, then the suspend_equivalent
+// flag is not cleared until we set the ext_suspended flag so
+// that wait_for_ext_suspend_completion() returns consistent
+// results.
+this->clear_suspend_equivalent();
+}
+// A racing resume may have cancelled us before we grabbed SR_lock
+// above. Or another external suspend request could be waiting for us
+// by the time we return from SR_lock()->wait(). The thread
+// that requested the suspension may already be trying to walk our
+// stack and if we return now, we can change the stack out from under
+// it. This would be a "bad thing (TM)" and cause the stack walker
+// to crash. We stay self-suspended until there are no more pending
+// external suspend requests.
+while (is_external_suspend()) {
+ret++;
+this->set_ext_suspended();
+// _ext_suspended flag is cleared by java_resume()
+while (is_ext_suspended()) {
+this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
+}
+}
+return ret;
+}
+#ifdef ASSERT
+// verify the JavaThread has not yet been published in the Threads::list, and
+// hence doesn't need protection from concurrent access at this stage
+void JavaThread::verify_not_published() {
+if (!Threads_lock->owned_by_self()) {
+MutexLockerEx ml(Threads_lock,  Mutex::_no_safepoint_check_flag);
+assert( !Threads::includes(this),
+"java thread shouldn't have been published yet!");
+}
+else {
+assert( !Threads::includes(this),
+"java thread shouldn't have been published yet!");
+}
+}
+#endif
+// Slow path when the native==>VM/Java barriers detect a safepoint is in
+// progress or when _suspend_flags is non-zero.
+// Current thread needs to self-suspend if there is a suspend request and/or
+// block if a safepoint is in progress.
+// Async exception ISN'T checked.
+// Note only the ThreadInVMfromNative transition can call this function
+// directly and when thread state is _thread_in_native_trans
+void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
+assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
+JavaThread *curJT = JavaThread::current();
+bool do_self_suspend = thread->is_external_suspend();
+assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
+// If JNIEnv proxies are allowed, don't self-suspend if the target
+// thread is not the current thread. In older versions of jdbx, jdbx
+// threads could call into the VM with another thread's JNIEnv so we
+// can be here operating on behalf of a suspended thread (4432884).
+if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
+JavaThreadState state = thread->thread_state();
+// We mark this thread_blocked state as a suspend-equivalent so
+// that a caller to is_ext_suspend_completed() won't be confused.
+// The suspend-equivalent state is cleared by java_suspend_self().
+thread->set_suspend_equivalent();
+// If the safepoint code sees the _thread_in_native_trans state, it will
+// wait until the thread changes to other thread state. There is no
+// guarantee on how soon we can obtain the SR_lock and complete the
+// self-suspend request. It would be a bad idea to let safepoint wait for
+// too long. Temporarily change the state to _thread_blocked to
+// let the VM thread know that this thread is ready for GC. The problem
+// of changing thread state is that safepoint could happen just after
+// java_suspend_self() returns after being resumed, and VM thread will
+// see the _thread_blocked state. We must check for safepoint
+// after restoring the state and make sure we won't leave while a safepoint
+// is in progress.
+thread->set_thread_state(_thread_blocked);
+thread->java_suspend_self();
+thread->set_thread_state(state);
+// Make sure new state is seen by VM thread
+if (os::is_MP()) {
+if (UseMembar) {
+// Force a fence between the write above and read below
+OrderAccess::fence();
+} else {
+// Must use this rather than serialization page in particular on Windows
+InterfaceSupport::serialize_memory(thread);
+}
+}
+}
+if (SafepointSynchronize::do_call_back()) {
+// If we are safepointing, then block the caller which may not be
+// the same as the target thread (see above).
+SafepointSynchronize::block(curJT);
+}
+if (thread->is_deopt_suspend()) {
+thread->clear_deopt_suspend();
+RegisterMap map(thread, false);
+frame f = thread->last_frame();
+while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
+f = f.sender(&map);
+}
+if (f.id() == thread->must_deopt_id()) {
+thread->clear_must_deopt_id();
+// Since we know we're safe to deopt the current state is a safe state
+f.deoptimize(thread, true);
+} else {
+fatal("missed deoptimization!");
+}
+}
+}
+// Slow path when the native==>VM/Java barriers detect a safepoint is in
+// progress or when _suspend_flags is non-zero.
+// Current thread needs to self-suspend if there is a suspend request and/or
+// block if a safepoint is in progress.
+// Also check for pending async exception (not including unsafe access error).
+// Note only the native==>VM/Java barriers can call this function and when
+// thread state is _thread_in_native_trans.
+void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
+check_safepoint_and_suspend_for_native_trans(thread);
+if (thread->has_async_exception()) {
+// We are in _thread_in_native_trans state, don't handle unsafe
+// access error since that may block.
+thread->check_and_handle_async_exceptions(false);
+}
+}
+// We need to guarantee the Threads_lock here, since resumes are not
+// allowed during safepoint synchronization
+// Can only resume from an external suspension
+void JavaThread::java_resume() {
+assert_locked_or_safepoint(Threads_lock);
+// Sanity check: thread is gone, has started exiting or the thread
+// was not externally suspended.
+if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
+return;
+}
+MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
+clear_external_suspend();
+if (is_ext_suspended()) {
+clear_ext_suspended();
+SR_lock()->notify_all();
+}
+}
+void JavaThread::create_stack_guard_pages() {
+if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
+address low_addr = stack_base() - stack_size();
+size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
+int allocate = os::allocate_stack_guard_pages();
+// warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
+if (allocate && !os::commit_memory((char *) low_addr, len)) {
+warning("Attempt to allocate stack guard pages failed.");
+return;
+}
+if (os::guard_memory((char *) low_addr, len)) {
+_stack_guard_state = stack_guard_enabled;
+} else {
+warning("Attempt to protect stack guard pages failed.");
+if (os::uncommit_memory((char *) low_addr, len)) {
+warning("Attempt to deallocate stack guard pages failed.");
+}
+}
+}
+void JavaThread::remove_stack_guard_pages() {
+if (_stack_guard_state == stack_guard_unused) return;
+address low_addr = stack_base() - stack_size();
+size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
+if (os::allocate_stack_guard_pages()) {
+if (os::uncommit_memory((char *) low_addr, len)) {
+_stack_guard_state = stack_guard_unused;
+} else {
+warning("Attempt to deallocate stack guard pages failed.");
+}
+} else {
+if (_stack_guard_state == stack_guard_unused) return;
+if (os::unguard_memory((char *) low_addr, len)) {
+_stack_guard_state = stack_guard_unused;
+} else {
+warning("Attempt to unprotect stack guard pages failed.");
+}
+}
+}
+void JavaThread::enable_stack_yellow_zone() {
+assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
+assert(_stack_guard_state != stack_guard_enabled, "already enabled");
+// The base notation is from the stacks point of view, growing downward.
+// We need to adjust it to work correctly with guard_memory()
+address base = stack_yellow_zone_base() - stack_yellow_zone_size();
+guarantee(base < stack_base(),"Error calculating stack yellow zone");
+guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
+if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
+_stack_guard_state = stack_guard_enabled;
+} else {
+warning("Attempt to guard stack yellow zone failed.");
+}
+enable_register_stack_guard();
+}
+void JavaThread::disable_stack_yellow_zone() {
+assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
+assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
+// Simply return if called for a thread that does not use guard pages.
+if (_stack_guard_state == stack_guard_unused) return;
+// The base notation is from the stacks point of view, growing downward.
+// We need to adjust it to work correctly with guard_memory()
+address base = stack_yellow_zone_base() - stack_yellow_zone_size();
+if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
+_stack_guard_state = stack_guard_yellow_disabled;
+} else {
+warning("Attempt to unguard stack yellow zone failed.");
+}
+disable_register_stack_guard();
+}
+void JavaThread::enable_stack_red_zone() {
+// The base notation is from the stacks point of view, growing downward.
+// We need to adjust it to work correctly with guard_memory()
+assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
+address base = stack_red_zone_base() - stack_red_zone_size();
+guarantee(base < stack_base(),"Error calculating stack red zone");
+guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
+if(!os::guard_memory((char *) base, stack_red_zone_size())) {
+warning("Attempt to guard stack red zone failed.");
+}
+}
+void JavaThread::disable_stack_red_zone() {
+// The base notation is from the stacks point of view, growing downward.
+// We need to adjust it to work correctly with guard_memory()
+assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
+address base = stack_red_zone_base() - stack_red_zone_size();
+if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
+warning("Attempt to unguard stack red zone failed.");
+}
+}
+void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
+// ignore is there is no stack
+if (!has_last_Java_frame()) return;
+// traverse the stack frames. Starts from top frame.
+for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
+frame* fr = fst.current();
+f(fr, fst.register_map());
+}
+}
+#ifndef PRODUCT
+// Deoptimization
+// Function for testing deoptimization
+void JavaThread::deoptimize() {
+// BiasedLocking needs an updated RegisterMap for the revoke monitors pass
+StackFrameStream fst(this, UseBiasedLocking);
+bool deopt = false;           // Dump stack only if a deopt actually happens.
+bool only_at = strlen(DeoptimizeOnlyAt) > 0;
+// Iterate over all frames in the thread and deoptimize
+for(; !fst.is_done(); fst.next()) {
+if(fst.current()->can_be_deoptimized()) {
+if (only_at) {
+// Deoptimize only at particular bcis.  DeoptimizeOnlyAt
+// consists of comma or carriage return separated numbers so
+// search for the current bci in that string.
+address pc = fst.current()->pc();
+nmethod* nm =  (nmethod*) fst.current()->cb();
+ScopeDesc* sd = nm->scope_desc_at( pc);
+char buffer[8];
+jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
+size_t len = strlen(buffer);
+const char * found = strstr(DeoptimizeOnlyAt, buffer);
+while (found != NULL) {
+if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
+(found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
+// Check that the bci found is bracketed by terminators.
+break;
+}
+found = strstr(found + 1, buffer);
+}
+if (!found) {
+continue;
+}
+}
+if (DebugDeoptimization && !deopt) {
+deopt = true; // One-time only print before deopt
+tty->print_cr("[BEFORE Deoptimization]");
+trace_frames();
+trace_stack();
+}
+Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
+}
+}
+if (DebugDeoptimization && deopt) {
+tty->print_cr("[AFTER Deoptimization]");
+trace_frames();
+}
+}
+// Make zombies
+void JavaThread::make_zombies() {
+for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
+if (fst.current()->can_be_deoptimized()) {
+// it is a Java nmethod
+nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
+nm->make_not_entrant();
+}
+}
+}
+#endif // PRODUCT
+void JavaThread::deoptimized_wrt_marked_nmethods() {
+if (!has_last_Java_frame()) return;
+// BiasedLocking needs an updated RegisterMap for the revoke monitors pass
+StackFrameStream fst(this, UseBiasedLocking);
+for(; !fst.is_done(); fst.next()) {
+if (fst.current()->should_be_deoptimized()) {
+Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
+}
+}
+}
+// GC support
+static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
+void JavaThread::gc_epilogue() {
+frames_do(frame_gc_epilogue);
+}
+static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
+void JavaThread::gc_prologue() {
+frames_do(frame_gc_prologue);
+}
+void JavaThread::oops_do(OopClosure* f) {
+// The ThreadProfiler oops_do is done from FlatProfiler::oops_do
+// since there may be more than one thread using each ThreadProfiler.
+// Traverse the GCHandles
+Thread::oops_do(f);
+assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
+(has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
+if (has_last_Java_frame()) {
+// Traverse the privileged stack
+if (_privileged_stack_top != NULL) {
+_privileged_stack_top->oops_do(f);
+}
+// traverse the registered growable array
+if (_array_for_gc != NULL) {
+for (int index = 0; index < _array_for_gc->length(); index++) {
+f->do_oop(_array_for_gc->adr_at(index));
+}
+}
+// Traverse the monitor chunks
+for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
+chunk->oops_do(f);
+}
+// Traverse the execution stack
+for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
+fst.current()->oops_do(f, fst.register_map());
+}
+}
+// callee_target is never live across a gc point so NULL it here should
+// it still contain a methdOop.
+set_callee_target(NULL);
+assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
+// If we have deferred set_locals there might be oops waiting to be
+// written
+GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
+if (list != NULL) {
+for (int i = 0; i < list->length(); i++) {
+list->at(i)->oops_do(f);
+}
+}
+// Traverse instance variables at the end since the GC may be moving things
+// around using this function
+f->do_oop((oop*) &_threadObj);
+f->do_oop((oop*) &_vm_result);
+f->do_oop((oop*) &_vm_result_2);
+f->do_oop((oop*) &_exception_oop);
+f->do_oop((oop*) &_pending_async_exception);
+if (jvmti_thread_state() != NULL) {
+jvmti_thread_state()->oops_do(f);
+}
+}
+void JavaThread::nmethods_do() {
+// Traverse the GCHandles
+Thread::nmethods_do();
+assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
+(has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
+if (has_last_Java_frame()) {
+// Traverse the execution stack
+for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
+fst.current()->nmethods_do();
+}
+}
+}
+// Printing
+const char* _get_thread_state_name(JavaThreadState _thread_state) {
+switch (_thread_state) {
+case _thread_uninitialized:     return "_thread_uninitialized";
+case _thread_new:               return "_thread_new";
+case _thread_new_trans:         return "_thread_new_trans";
+case _thread_in_native:         return "_thread_in_native";
+case _thread_in_native_trans:   return "_thread_in_native_trans";
+case _thread_in_vm:             return "_thread_in_vm";
+case _thread_in_vm_trans:       return "_thread_in_vm_trans";
+case _thread_in_Java:           return "_thread_in_Java";
+case _thread_in_Java_trans:     return "_thread_in_Java_trans";
+case _thread_blocked:           return "_thread_blocked";
+case _thread_blocked_trans:     return "_thread_blocked_trans";
+default:                        return "unknown thread state";
+}
+}
+#ifndef PRODUCT
+void JavaThread::print_thread_state_on(outputStream *st) const {
+st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
+};
+void JavaThread::print_thread_state() const {
+print_thread_state_on(tty);
+};
+#endif // PRODUCT
+// Called by Threads::print() for VM_PrintThreads operation
+void JavaThread::print_on(outputStream *st) const {
+st->print("\"%s\" ", get_thread_name());
+oop thread_oop = threadObj();
+if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
+Thread::print_on(st);
+// print guess for valid stack memory region (assume 4K pages); helps lock debugging
+st->print_cr("[" INTPTR_FORMAT ".." INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12), highest_lock());
+if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
+st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
+}
+#ifndef PRODUCT
+print_thread_state_on(st);
+_safepoint_state->print_on(st);
+#endif // PRODUCT
+}
+// Called by fatal error handler. The difference between this and
+// JavaThread::print() is that we can't grab lock or allocate memory.
+void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
+st->print("JavaThread \"%s\"",  get_thread_name_string(buf, buflen));
+oop thread_obj = threadObj();
+if (thread_obj != NULL) {
+if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
+}
+st->print(" [");
+st->print("%s", _get_thread_state_name(_thread_state));
+if (osthread()) {
+st->print(", id=%d", osthread()->thread_id());
+}
+st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
+_stack_base - _stack_size, _stack_base);
+st->print("]");
+return;
+}
+// Verification
+static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
+void JavaThread::verify() {
+// Verify oops in the thread.
+oops_do(&VerifyOopClosure::verify_oop);
+// Verify the stack frames.
+frames_do(frame_verify);
+}
+// CR 6300358 (sub-CR 2137150)
+// Most callers of this method assume that it can't return NULL but a
+// thread may not have a name whilst it is in the process of attaching to
+// the VM - see CR 6412693, and there are places where a JavaThread can be
+// seen prior to having it's threadObj set (eg JNI attaching threads and
+// if vm exit occurs during initialization). These cases can all be accounted
+// for such that this method never returns NULL.
+const char* JavaThread::get_thread_name() const {
+#ifdef ASSERT
+// early safepoints can hit while current thread does not yet have TLS
+if (!SafepointSynchronize::is_at_safepoint()) {
+Thread *cur = Thread::current();
+if (!(cur->is_Java_thread() && cur == this)) {
+// Current JavaThreads are allowed to get their own name without
+// the Threads_lock.
+assert_locked_or_safepoint(Threads_lock);
+}
+}
+#endif // ASSERT
+return get_thread_name_string();
+}
+// Returns a non-NULL representation of this thread's name, or a suitable
+// descriptive string if there is no set name
+const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
+const char* name_str;
+oop thread_obj = threadObj();
+if (thread_obj != NULL) {
+typeArrayOop name = java_lang_Thread::name(thread_obj);
+if (name != NULL) {
+if (buf == NULL) {
+name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
+}
+else {
+name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
+}
+}
+else if (is_attaching()) { // workaround for 6412693 - see 6404306
+name_str = "<no-name - thread is attaching>";
+}
+else {
+name_str = Thread::name();
+}
+}
+else {
+name_str = Thread::name();
+}
+assert(name_str != NULL, "unexpected NULL thread name");
+return name_str;
+}
+const char* JavaThread::get_threadgroup_name() const {
+debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
+oop thread_obj = threadObj();
+if (thread_obj != NULL) {
+oop thread_group = java_lang_Thread::threadGroup(thread_obj);
+if (thread_group != NULL) {
+typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
+// ThreadGroup.name can be null
+if (name != NULL) {
+const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
+return str;
+}
+}
+}
+return NULL;
+}
+const char* JavaThread::get_parent_name() const {
+debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
+oop thread_obj = threadObj();
+if (thread_obj != NULL) {
+oop thread_group = java_lang_Thread::threadGroup(thread_obj);
+if (thread_group != NULL) {
+oop parent = java_lang_ThreadGroup::parent(thread_group);
+if (parent != NULL) {
+typeArrayOop name = java_lang_ThreadGroup::name(parent);
+// ThreadGroup.name can be null
+if (name != NULL) {
+const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
+return str;
+}
+}
+}
+}
+return NULL;
+}
+ThreadPriority JavaThread::java_priority() const {
+oop thr_oop = threadObj();
+if (thr_oop == NULL) return NormPriority; // Bootstrapping
+ThreadPriority priority = java_lang_Thread::priority(thr_oop);
+assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
+return priority;
+}
+void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
+assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
+// Link Java Thread object <-> C++ Thread
+// Get the C++ thread object (an oop) from the JNI handle (a jthread)
+// and put it into a new Handle.  The Handle "thread_oop" can then
+// be used to pass the C++ thread object to other methods.
+// Set the Java level thread object (jthread) field of the
+// new thread (a JavaThread *) to C++ thread object using the
+// "thread_oop" handle.
+// Set the thread field (a JavaThread *) of the
+// oop representing the java_lang_Thread to the new thread (a JavaThread *).
+Handle thread_oop(Thread::current(),
+JNIHandles::resolve_non_null(jni_thread));
+assert(instanceKlass::cast(thread_oop->klass())->is_linked(),
+"must be initialized");
+set_threadObj(thread_oop());
+java_lang_Thread::set_thread(thread_oop(), this);
+if (prio == NoPriority) {
+prio = java_lang_Thread::priority(thread_oop());
+assert(prio != NoPriority, "A valid priority should be present");
+}
+// Push the Java priority down to the native thread; needs Threads_lock
+Thread::set_priority(this, prio);
+// Add the new thread to the Threads list and set it in motion.
+// We must have threads lock in order to call Threads::add.
+// It is crucial that we do not block before the thread is
+// added to the Threads list for if a GC happens, then the java_thread oop
+// will not be visited by GC.
+Threads::add(this);
+}
+oop JavaThread::current_park_blocker() {
+// Support for JSR-166 locks
+oop thread_oop = threadObj();
+if (thread_oop != NULL && JDK_Version::supports_thread_park_blocker()) {
+return java_lang_Thread::park_blocker(thread_oop);
+}
+return NULL;
+}
+void JavaThread::print_stack_on(outputStream* st) {
+if (!has_last_Java_frame()) return;
+ResourceMark rm;
+HandleMark   hm;
+RegisterMap reg_map(this);
+vframe* start_vf = last_java_vframe(&reg_map);
+int count = 0;
+for (vframe* f = start_vf; f; f = f->sender() ) {
+if (f->is_java_frame()) {
+javaVFrame* jvf = javaVFrame::cast(f);
+java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
+// Print out lock information
+if (JavaMonitorsInStackTrace) {
+jvf->print_lock_info_on(st, count);
+}
+} else {
+// Ignore non-Java frames
+}
+// Bail-out case for too deep stacks
+count++;
+if (MaxJavaStackTraceDepth == count) return;
+}
+}
+// JVMTI PopFrame support
+void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
+assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
+if (in_bytes(size_in_bytes) != 0) {
+_popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes));
+_popframe_preserved_args_size = in_bytes(size_in_bytes);
+Copy::conjoint_bytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
+}
+}
+void* JavaThread::popframe_preserved_args() {
+return _popframe_preserved_args;
+}
+ByteSize JavaThread::popframe_preserved_args_size() {
+return in_ByteSize(_popframe_preserved_args_size);
+}
+WordSize JavaThread::popframe_preserved_args_size_in_words() {
+int sz = in_bytes(popframe_preserved_args_size());
+assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
+return in_WordSize(sz / wordSize);
+}
+void JavaThread::popframe_free_preserved_args() {
+assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
+FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
+_popframe_preserved_args = NULL;
+_popframe_preserved_args_size = 0;
+}
+#ifndef PRODUCT
+void JavaThread::trace_frames() {
+tty->print_cr("[Describe stack]");
+int frame_no = 1;
+for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
+tty->print("  %d. ", frame_no++);
+fst.current()->print_value_on(tty,this);
+tty->cr();
+}
+}
+void JavaThread::trace_stack_from(vframe* start_vf) {
+ResourceMark rm;
+int vframe_no = 1;
+for (vframe* f = start_vf; f; f = f->sender() ) {
+if (f->is_java_frame()) {
+javaVFrame::cast(f)->print_activation(vframe_no++);
+} else {
+f->print();
+}
+if (vframe_no > StackPrintLimit) {
+tty->print_cr("...<more frames>...");
+return;
+}
+}
+}
+void JavaThread::trace_stack() {
+if (!has_last_Java_frame()) return;
+ResourceMark rm;
+HandleMark   hm;
+RegisterMap reg_map(this);
+trace_stack_from(last_java_vframe(&reg_map));
+}
+#endif // PRODUCT
+javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
+assert(reg_map != NULL, "a map must be given");
+frame f = last_frame();
+for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
+if (vf->is_java_frame()) return javaVFrame::cast(vf);
+}
+return NULL;
+}
+klassOop JavaThread::security_get_caller_class(int depth) {
+vframeStream vfst(this);
+vfst.security_get_caller_frame(depth);
+if (!vfst.at_end()) {
+return vfst.method()->method_holder();
+}
+return NULL;
+}
+static void compiler_thread_entry(JavaThread* thread, TRAPS) {
+assert(thread->is_Compiler_thread(), "must be compiler thread");
+CompileBroker::compiler_thread_loop();
+}
+// Create a CompilerThread
+CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
+: JavaThread(&compiler_thread_entry) {
+_env   = NULL;
+_log   = NULL;
+_task  = NULL;
+_queue = queue;
+_counters = counters;
+#ifndef PRODUCT
+_ideal_graph_printer = NULL;
+#endif
+}
+// ======= Threads ========
+// The Threads class links together all active threads, and provides
+// operations over all threads.  It is protected by its own Mutex
+// lock, which is also used in other contexts to protect thread
+// operations from having the thread being operated on from exiting
+// and going away unexpectedly (e.g., safepoint synchronization)
+JavaThread* Threads::_thread_list = NULL;
+int         Threads::_number_of_threads = 0;
+int         Threads::_number_of_non_daemon_threads = 0;
+int         Threads::_return_code = 0;
+size_t      JavaThread::_stack_size_at_create = 0;
+// All JavaThreads
+#define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
+void os_stream();
+// All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
+void Threads::threads_do(ThreadClosure* tc) {
+assert_locked_or_safepoint(Threads_lock);
+// ALL_JAVA_THREADS iterates through all JavaThreads
+ALL_JAVA_THREADS(p) {
+tc->do_thread(p);
+}
+// Someday we could have a table or list of all non-JavaThreads.
+// For now, just manually iterate through them.
+tc->do_thread(VMThread::vm_thread());
+Universe::heap()->gc_threads_do(tc);
+tc->do_thread(WatcherThread::watcher_thread());
+// If CompilerThreads ever become non-JavaThreads, add them here
+}
+jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
+// Check version
+if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
+// Initialize the output stream module
+ostream_init();
+// Process java launcher properties.
+Arguments::process_sun_java_launcher_properties(args);
+// Initialize the os module before using TLS
+os::init();
+// Initialize system properties.
+Arguments::init_system_properties();
+// Parse arguments
+jint parse_result = Arguments::parse(args);
+if (parse_result != JNI_OK) return parse_result;
+if (PauseAtStartup) {
+os::pause();
+}
+HS_DTRACE_PROBE(hotspot, vm__init__begin);
+// Record VM creation timing statistics
+TraceVmCreationTime create_vm_timer;
+create_vm_timer.start();
+// Timing (must come after argument parsing)
+TraceTime timer("Create VM", TraceStartupTime);
+// Initialize the os module after parsing the args
+jint os_init_2_result = os::init_2();
+if (os_init_2_result != JNI_OK) return os_init_2_result;
+// Initialize output stream logging
+ostream_init_log();
+// Convert -Xrun to -agentlib: if there is no JVM_OnLoad
+// Must be before create_vm_init_agents()
+if (Arguments::init_libraries_at_startup()) {
+convert_vm_init_libraries_to_agents();
+}
+// Launch -agentlib/-agentpath and converted -Xrun agents
+if (Arguments::init_agents_at_startup()) {
+create_vm_init_agents();
+}
+// Initialize Threads state
+_thread_list = NULL;
+_number_of_threads = 0;
+_number_of_non_daemon_threads = 0;
+// Initialize TLS
+ThreadLocalStorage::init();
+// Initialize global data structures and create system classes in heap
+vm_init_globals();
+// Attach the main thread to this os thread
+JavaThread* main_thread = new JavaThread();
+main_thread->set_thread_state(_thread_in_vm);
+// must do this before set_active_handles and initialize_thread_local_storage
+// Note: on solaris initialize_thread_local_storage() will (indirectly)
+// change the stack size recorded here to one based on the java thread
+// stacksize. This adjusted size is what is used to figure the placement
+// of the guard pages.
+main_thread->record_stack_base_and_size();
+main_thread->initialize_thread_local_storage();
+main_thread->set_active_handles(JNIHandleBlock::allocate_block());
+if (!main_thread->set_as_starting_thread()) {
+vm_shutdown_during_initialization(
+"Failed necessary internal allocation. Out of swap space");
+delete main_thread;
+*canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
+return JNI_ENOMEM;
+}
+// Enable guard page *after* os::create_main_thread(), otherwise it would
+// crash Linux VM, see notes in os_linux.cpp.
+main_thread->create_stack_guard_pages();
+// Initialize Java-Leve synchronization subsystem
+ObjectSynchronizer::Initialize() ;
+// Initialize global modules
+jint status = init_globals();
+if (status != JNI_OK) {
+delete main_thread;
+*canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
+return status;
+}
+HandleMark hm;
+{ MutexLocker mu(Threads_lock);
+Threads::add(main_thread);
+}
+// Any JVMTI raw monitors entered in onload will transition into
+// real raw monitor. VM is setup enough here for raw monitor enter.
+JvmtiExport::transition_pending_onload_raw_monitors();
+if (VerifyBeforeGC &&
+Universe::heap()->total_collections() >= VerifyGCStartAt) {
+Universe::heap()->prepare_for_verify();
+Universe::verify();   // make sure we're starting with a clean slate
+}
+// Create the VMThread
+{ TraceTime timer("Start VMThread", TraceStartupTime);
+VMThread::create();
+Thread* vmthread = VMThread::vm_thread();
+if (!os::create_thread(vmthread, os::vm_thread))
+vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
+// Wait for the VM thread to become ready, and VMThread::run to initialize
+// Monitors can have spurious returns, must always check another state flag
+{
+MutexLocker ml(Notify_lock);
+os::start_thread(vmthread);
+while (vmthread->active_handles() == NULL) {
+Notify_lock->wait();
+}
+}
+}
+assert (Universe::is_fully_initialized(), "not initialized");
+EXCEPTION_MARK;
+// At this point, the Universe is initialized, but we have not executed
+// any byte code.  Now is a good time (the only time) to dump out the
+// internal state of the JVM for sharing.
+if (DumpSharedSpaces) {
+Universe::heap()->preload_and_dump(CHECK_0);
+ShouldNotReachHere();
+}
+// Always call even when there are not JVMTI environments yet, since environments
+// may be attached late and JVMTI must track phases of VM execution
+JvmtiExport::enter_start_phase();
+// Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
+JvmtiExport::post_vm_start();
+{
+TraceTime timer("Initialize java.lang classes", TraceStartupTime);
+if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
+create_vm_init_libraries();
+}
+if (InitializeJavaLangString) {
+initialize_class(vmSymbolHandles::java_lang_String(), CHECK_0);
+} else {
+warning("java.lang.String not initialized");
+}
+// Initialize java_lang.System (needed before creating the thread)
+if (InitializeJavaLangSystem) {
+initialize_class(vmSymbolHandles::java_lang_System(), CHECK_0);
+initialize_class(vmSymbolHandles::java_lang_ThreadGroup(), CHECK_0);
+Handle thread_group = create_initial_thread_group(CHECK_0);
+Universe::set_main_thread_group(thread_group());
+initialize_class(vmSymbolHandles::java_lang_Thread(), CHECK_0);
+oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
+main_thread->set_threadObj(thread_object);
+// Set thread status to running since main thread has
+// been started and running.
+java_lang_Thread::set_thread_status(thread_object,
+java_lang_Thread::RUNNABLE);
+// The VM preresolve methods to these classes. Make sure that get initialized
+initialize_class(vmSymbolHandles::java_lang_reflect_Method(), CHECK_0);
+initialize_class(vmSymbolHandles::java_lang_ref_Finalizer(),  CHECK_0);
+// The VM creates & returns objects of this class. Make sure it's initialized.
+initialize_class(vmSymbolHandles::java_lang_Class(), CHECK_0);
+call_initializeSystemClass(CHECK_0);
+} else {
+warning("java.lang.System not initialized");
+}
+// an instance of OutOfMemory exception has been allocated earlier
+if (InitializeJavaLangExceptionsErrors) {
+initialize_class(vmSymbolHandles::java_lang_OutOfMemoryError(), CHECK_0);
+initialize_class(vmSymbolHandles::java_lang_NullPointerException(), CHECK_0);
+initialize_class(vmSymbolHandles::java_lang_ClassCastException(), CHECK_0);
+initialize_class(vmSymbolHandles::java_lang_ArrayStoreException(), CHECK_0);
+initialize_class(vmSymbolHandles::java_lang_ArithmeticException(), CHECK_0);
+initialize_class(vmSymbolHandles::java_lang_StackOverflowError(), CHECK_0);
+initialize_class(vmSymbolHandles::java_lang_IllegalMonitorStateException(), CHECK_0);
+} else {
+warning("java.lang.OutOfMemoryError has not been initialized");
+warning("java.lang.NullPointerException has not been initialized");
+warning("java.lang.ClassCastException has not been initialized");
+warning("java.lang.ArrayStoreException has not been initialized");
+warning("java.lang.ArithmeticException has not been initialized");
+warning("java.lang.StackOverflowError has not been initialized");
+}
+}
+// See        : bugid 4211085.
+// Background : the static initializer of java.lang.Compiler tries to read
+//              property"java.compiler" and read & write property "java.vm.info".
+//              When a security manager is installed through the command line
+//              option "-Djava.security.manager", the above properties are not
+//              readable and the static initializer for java.lang.Compiler fails
+//              resulting in a NoClassDefFoundError.  This can happen in any
+//              user code which calls methods in java.lang.Compiler.
+// Hack :       the hack is to pre-load and initialize this class, so that only
+//              system domains are on the stack when the properties are read.
+//              Currently even the AWT code has calls to methods in java.lang.Compiler.
+//              On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
+// Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
+//              read and write"java.vm.info" in the default policy file. See bugid 4211383
+//              Once that is done, we should remove this hack.
+initialize_class(vmSymbolHandles::java_lang_Compiler(), CHECK_0);
+// More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
+// the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
+// compiler does not get loaded through java.lang.Compiler).  "java -version" with the
+// hotspot vm says "nojit" all the time which is confusing.  So, we reset it here.
+// This should also be taken out as soon as 4211383 gets fixed.
+reset_vm_info_property(CHECK_0);
+quicken_jni_functions();
+// Set flag that basic initialization has completed. Used by exceptions and various
+// debug stuff, that does not work until all basic classes have been initialized.
+set_init_completed();
+HS_DTRACE_PROBE(hotspot, vm__init__end);
+// record VM initialization completion time
+Management::record_vm_init_completed();
+// Compute system loader. Note that this has to occur after set_init_completed, since
+// valid exceptions may be thrown in the process.
+// Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
+// set_init_completed has just been called, causing exceptions not to be shortcut
+// anymore. We call vm_exit_during_initialization directly instead.
+SystemDictionary::compute_java_system_loader(THREAD);
+if (HAS_PENDING_EXCEPTION) {
+vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
+}
+#ifndef SERIALGC
+// Support for ConcurrentMarkSweep. This should be cleaned up
+// and better encapsulated. XXX YSR
+if (UseConcMarkSweepGC) {
+ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
+if (HAS_PENDING_EXCEPTION) {
+vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
+}
+}
+#endif // SERIALGC
+// Always call even when there are not JVMTI environments yet, since environments
+// may be attached late and JVMTI must track phases of VM execution
+JvmtiExport::enter_live_phase();
+// Signal Dispatcher needs to be started before VMInit event is posted
+os::signal_init();
+// Start Attach Listener if +StartAttachListener or it can't be started lazily
+if (!DisableAttachMechanism) {
+if (StartAttachListener || AttachListener::init_at_startup()) {
+AttachListener::init();
+}
+}
+// Launch -Xrun agents
+// Must be done in the JVMTI live phase so that for backward compatibility the JDWP
+// back-end can launch with -Xdebug -Xrunjdwp.
+if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
+create_vm_init_libraries();
+}
+// Notify JVMTI agents that VM initialization is complete - nop if no agents.
+JvmtiExport::post_vm_initialized();
+Chunk::start_chunk_pool_cleaner_task();
+// initialize compiler(s)
+CompileBroker::compilation_init();
+Management::initialize(THREAD);
+if (HAS_PENDING_EXCEPTION) {
+// management agent fails to start possibly due to
+// configuration problem and is responsible for printing
+// stack trace if appropriate. Simply exit VM.
+vm_exit(1);
+}
+if (Arguments::has_profile())       FlatProfiler::engage(main_thread, true);
+if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
+if (MemProfiling)                   MemProfiler::engage();
+StatSampler::engage();
+if (CheckJNICalls)                  JniPeriodicChecker::engage();
+if (CacheTimeMillis)                TimeMillisUpdateTask::engage();
+BiasedLocking::init();
+// Start up the WatcherThread if there are any periodic tasks
+// NOTE:  All PeriodicTasks should be registered by now. If they
+//   aren't, late joiners might appear to start slowly (we might
+//   take a while to process their first tick).
+if (PeriodicTask::num_tasks() > 0) {
+WatcherThread::start();
+}
+create_vm_timer.end();
+return JNI_OK;
+}
+// type for the Agent_OnLoad and JVM_OnLoad entry points
+extern "C" {
+typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
+}
+// Find a command line agent library and return its entry point for
+//         -agentlib:  -agentpath:   -Xrun
+// num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
+static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
+OnLoadEntry_t on_load_entry = NULL;
+void *library = agent->os_lib();  // check if we have looked it up before
+if (library == NULL) {
+char buffer[JVM_MAXPATHLEN];
+char ebuf[1024];
+const char *name = agent->name();
+if (agent->is_absolute_path()) {
+library = hpi::dll_load(name, ebuf, sizeof ebuf);
+if (library == NULL) {
+// If we can't find the agent, exit.
+vm_exit_during_initialization("Could not find agent library in absolute path", name);
+}
+} else {
+// Try to load the agent from the standard dll directory
+hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name);
+library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
+#ifdef KERNEL
+// Download instrument dll
+if (library == NULL && strcmp(name, "instrument") == 0) {
+char *props = Arguments::get_kernel_properties();
+char *home  = Arguments::get_java_home();
+const char *fmt   = "%s/bin/java %s -Dkernel.background.download=false"
+" sun.jkernel.DownloadManager -download client_jvm";
+int length = strlen(props) + strlen(home) + strlen(fmt) + 1;
+char *cmd = AllocateHeap(length);
+jio_snprintf(cmd, length, fmt, home, props);
+int status = os::fork_and_exec(cmd);
+FreeHeap(props);
+FreeHeap(cmd);
+if (status == -1) {
+warning(cmd);
+vm_exit_during_initialization("fork_and_exec failed: %s",
+strerror(errno));
+}
+// when this comes back the instrument.dll should be where it belongs.
+library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
+}
+#endif // KERNEL
+if (library == NULL) { // Try the local directory
+char ns[1] = {0};
+hpi::dll_build_name(buffer, sizeof(buffer), ns, name);
+library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
+if (library == NULL) {
+// If we can't find the agent, exit.
+vm_exit_during_initialization("Could not find agent library on the library path or in the local directory", name);
+}
+}
+}
+agent->set_os_lib(library);
+}
+// Find the OnLoad function.
+for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
+on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, hpi::dll_lookup(library, on_load_symbols[symbol_index]));
+if (on_load_entry != NULL) break;
+}
+return on_load_entry;
+}
+// Find the JVM_OnLoad entry point
+static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
+const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
+return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
+}
+// Find the Agent_OnLoad entry point
+static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
+const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
+return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
+}
+// For backwards compatibility with -Xrun
+// Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
+// treated like -agentpath:
+// Must be called before agent libraries are created
+void Threads::convert_vm_init_libraries_to_agents() {
+AgentLibrary* agent;
+AgentLibrary* next;
+for (agent = Arguments::libraries(); agent != NULL; agent = next) {
+next = agent->next();  // cache the next agent now as this agent may get moved off this list
+OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
+// If there is an JVM_OnLoad function it will get called later,
+// otherwise see if there is an Agent_OnLoad
+if (on_load_entry == NULL) {
+on_load_entry = lookup_agent_on_load(agent);
+if (on_load_entry != NULL) {
+// switch it to the agent list -- so that Agent_OnLoad will be called,
+// JVM_OnLoad won't be attempted and Agent_OnUnload will
+Arguments::convert_library_to_agent(agent);
+} else {
+vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
+}
+}
+}
+}
+// Create agents for -agentlib:  -agentpath:  and converted -Xrun
+// Invokes Agent_OnLoad
+// Called very early -- before JavaThreads exist
+void Threads::create_vm_init_agents() {
+extern struct JavaVM_ main_vm;
+AgentLibrary* agent;
+JvmtiExport::enter_onload_phase();
+for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
+OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
+if (on_load_entry != NULL) {
+// Invoke the Agent_OnLoad function
+jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
+if (err != JNI_OK) {
+vm_exit_during_initialization("agent library failed to init", agent->name());
+}
+} else {
+vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
+}
+}
+JvmtiExport::enter_primordial_phase();
+}
+extern "C" {
+typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
+}
+void Threads::shutdown_vm_agents() {
+// Send any Agent_OnUnload notifications
+const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
+extern struct JavaVM_ main_vm;
+for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
+// Find the Agent_OnUnload function.
+for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
+Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
+hpi::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
+// Invoke the Agent_OnUnload function
+if (unload_entry != NULL) {
+JavaThread* thread = JavaThread::current();
+ThreadToNativeFromVM ttn(thread);
+HandleMark hm(thread);
+(*unload_entry)(&main_vm);
+break;
+}
+}
+}
+}
+// Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
+// Invokes JVM_OnLoad
+void Threads::create_vm_init_libraries() {
+extern struct JavaVM_ main_vm;
+AgentLibrary* agent;
+for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
+OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
+if (on_load_entry != NULL) {
+// Invoke the JVM_OnLoad function
+JavaThread* thread = JavaThread::current();
+ThreadToNativeFromVM ttn(thread);
+HandleMark hm(thread);
+jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
+if (err != JNI_OK) {
+vm_exit_during_initialization("-Xrun library failed to init", agent->name());
+}
+} else {
+vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
+}
+}
+}
+// Last thread running calls java.lang.Shutdown.shutdown()
+void JavaThread::invoke_shutdown_hooks() {
+HandleMark hm(this);
+// We could get here with a pending exception, if so clear it now.
+if (this->has_pending_exception()) {
+this->clear_pending_exception();
+}
+EXCEPTION_MARK;
+klassOop k =
+SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_Shutdown(),
+THREAD);
+if (k != NULL) {
+// SystemDictionary::resolve_or_null will return null if there was
+// an exception.  If we cannot load the Shutdown class, just don't
+// call Shutdown.shutdown() at all.  This will mean the shutdown hooks
+// and finalizers (if runFinalizersOnExit is set) won't be run.
+// Note that if a shutdown hook was registered or runFinalizersOnExit
+// was called, the Shutdown class would have already been loaded
+// (Runtime.addShutdownHook and runFinalizersOnExit will load it).
+instanceKlassHandle shutdown_klass (THREAD, k);
+JavaValue result(T_VOID);
+JavaCalls::call_static(&result,
+shutdown_klass,
+vmSymbolHandles::shutdown_method_name(),
+vmSymbolHandles::void_method_signature(),
+THREAD);
+}
+CLEAR_PENDING_EXCEPTION;
+}
+// Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
+// the program falls off the end of main(). Another VM exit path is through
+// vm_exit() when the program calls System.exit() to return a value or when
+// there is a serious error in VM. The two shutdown paths are not exactly
+// the same, but they share Shutdown.shutdown() at Java level and before_exit()
+// and VM_Exit op at VM level.
+//
+// Shutdown sequence:
+//   + Wait until we are the last non-daemon thread to execute
+//     <-- every thing is still working at this moment -->
+//   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
+//        shutdown hooks, run finalizers if finalization-on-exit
+//   + Call before_exit(), prepare for VM exit
+//      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
+//        currently the only user of this mechanism is File.deleteOnExit())
+//      > stop flat profiler, StatSampler, watcher thread, CMS threads,
+//        post thread end and vm death events to JVMTI,
+//        stop signal thread
+//   + Call JavaThread::exit(), it will:
+//      > release JNI handle blocks, remove stack guard pages
+//      > remove this thread from Threads list
+//     <-- no more Java code from this thread after this point -->
+//   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
+//     the compiler threads at safepoint
+//     <-- do not use anything that could get blocked by Safepoint -->
+//   + Disable tracing at JNI/JVM barriers
+//   + Set _vm_exited flag for threads that are still running native code
+//   + Delete this thread
+//   + Call exit_globals()
+//      > deletes tty
+//      > deletes PerfMemory resources
+//   + Return to caller
+bool Threads::destroy_vm() {
+JavaThread* thread = JavaThread::current();
+// Wait until we are the last non-daemon thread to execute
+{ MutexLocker nu(Threads_lock);
+while (Threads::number_of_non_daemon_threads() > 1 )
+// This wait should make safepoint checks, wait without a timeout,
+// and wait as a suspend-equivalent condition.
+//
+// Note: If the FlatProfiler is running and this thread is waiting
+// for another non-daemon thread to finish, then the FlatProfiler
+// is waiting for the external suspend request on this thread to
+// complete. wait_for_ext_suspend_completion() will eventually
+// timeout, but that takes time. Making this wait a suspend-
+// equivalent condition solves that timeout problem.
+//
+Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
+Mutex::_as_suspend_equivalent_flag);
+}
+// Hang forever on exit if we are reporting an error.
+if (ShowMessageBoxOnError && is_error_reported()) {
+os::infinite_sleep();
+}
+if (JDK_Version::is_jdk12x_version()) {
+// We are the last thread running, so check if finalizers should be run.
+// For 1.3 or later this is done in thread->invoke_shutdown_hooks()
+HandleMark rm(thread);
+Universe::run_finalizers_on_exit();
+} else {
+// run Java level shutdown hooks
+thread->invoke_shutdown_hooks();
+}
+before_exit(thread);
+thread->exit(true);
+// Stop VM thread.
+{
+// 4945125 The vm thread comes to a safepoint during exit.
+// GC vm_operations can get caught at the safepoint, and the
+// heap is unparseable if they are caught. Grab the Heap_lock
+// to prevent this. The GC vm_operations will not be able to
+// queue until after the vm thread is dead.
+MutexLocker ml(Heap_lock);
+VMThread::wait_for_vm_thread_exit();
+assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
+VMThread::destroy();
+}
+// clean up ideal graph printers
+#if defined(COMPILER2) && !defined(PRODUCT)
+IdealGraphPrinter::clean_up();
+#endif
+// Now, all Java threads are gone except daemon threads. Daemon threads
+// running Java code or in VM are stopped by the Safepoint. However,
+// daemon threads executing native code are still running.  But they
+// will be stopped at native=>Java/VM barriers. Note that we can't
+// simply kill or suspend them, as it is inherently deadlock-prone.
+#ifndef PRODUCT
+// disable function tracing at JNI/JVM barriers
+TraceHPI = false;
+TraceJNICalls = false;
+TraceJVMCalls = false;
+TraceRuntimeCalls = false;
+#endif
+VM_Exit::set_vm_exited();
+notify_vm_shutdown();
+delete thread;
+// exit_globals() will delete tty
+exit_globals();
+return true;
+}
+jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
+if (version == JNI_VERSION_1_1) return JNI_TRUE;
+return is_supported_jni_version(version);
+}
+jboolean Threads::is_supported_jni_version(jint version) {
+if (version == JNI_VERSION_1_2) return JNI_TRUE;
+if (version == JNI_VERSION_1_4) return JNI_TRUE;
+if (version == JNI_VERSION_1_6) return JNI_TRUE;
+return JNI_FALSE;
+}
+void Threads::add(JavaThread* p, bool force_daemon) {
+// The threads lock must be owned at this point
+assert_locked_or_safepoint(Threads_lock);
+p->set_next(_thread_list);
+_thread_list = p;
+_number_of_threads++;
+oop threadObj = p->threadObj();
+bool daemon = true;
+// Bootstrapping problem: threadObj can be null for initial
+// JavaThread (or for threads attached via JNI)
+if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
+_number_of_non_daemon_threads++;
+daemon = false;
+}
+ThreadService::add_thread(p, daemon);
+// Possible GC point.
+Events::log("Thread added: " INTPTR_FORMAT, p);
+}
+void Threads::remove(JavaThread* p) {
+// Extra scope needed for Thread_lock, so we can check
+// that we do not remove thread without safepoint code notice
+{ MutexLocker ml(Threads_lock);
+assert(includes(p), "p must be present");
+JavaThread* current = _thread_list;
+JavaThread* prev    = NULL;
+while (current != p) {
+prev    = current;
+current = current->next();
+}
+if (prev) {
+prev->set_next(current->next());
+} else {
+_thread_list = p->next();
+}
+_number_of_threads--;
+oop threadObj = p->threadObj();
+bool daemon = true;
+if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
+_number_of_non_daemon_threads--;
+daemon = false;
+// Only one thread left, do a notify on the Threads_lock so a thread waiting
+// on destroy_vm will wake up.
+if (number_of_non_daemon_threads() == 1)
+Threads_lock->notify_all();
+}
+ThreadService::remove_thread(p, daemon);
+// Make sure that safepoint code disregard this thread. This is needed since
+// the thread might mess around with locks after this point. This can cause it
+// to do callbacks into the safepoint code. However, the safepoint code is not aware
+// of this thread since it is removed from the queue.
+p->set_terminated_value();
+} // unlock Threads_lock
+// Since Events::log uses a lock, we grab it outside the Threads_lock
+Events::log("Thread exited: " INTPTR_FORMAT, p);
+}
+// Threads_lock must be held when this is called (or must be called during a safepoint)
+bool Threads::includes(JavaThread* p) {
+assert(Threads_lock->is_locked(), "sanity check");
+ALL_JAVA_THREADS(q) {
+if (q == p ) {
+return true;
+}
+}
+return false;
+}
+// Operations on the Threads list for GC.  These are not explicitly locked,
+// but the garbage collector must provide a safe context for them to run.
+// In particular, these things should never be called when the Threads_lock
+// is held by some other thread. (Note: the Safepoint abstraction also
+// uses the Threads_lock to gurantee this property. It also makes sure that
+// all threads gets blocked when exiting or starting).
+void Threads::oops_do(OopClosure* f) {
+ALL_JAVA_THREADS(p) {
+p->oops_do(f);
+}
+VMThread::vm_thread()->oops_do(f);
+}
+void Threads::possibly_parallel_oops_do(OopClosure* f) {
+// Introduce a mechanism allowing parallel threads to claim threads as
+// root groups.  Overhead should be small enough to use all the time,
+// even in sequential code.
+SharedHeap* sh = SharedHeap::heap();
+bool is_par = (sh->n_par_threads() > 0);
+int cp = SharedHeap::heap()->strong_roots_parity();
+ALL_JAVA_THREADS(p) {
+if (p->claim_oops_do(is_par, cp)) {
+p->oops_do(f);
+}
+}
+VMThread* vmt = VMThread::vm_thread();
+if (vmt->claim_oops_do(is_par, cp))
+vmt->oops_do(f);
+}
+#ifndef SERIALGC
+// Used by ParallelScavenge
+void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
+ALL_JAVA_THREADS(p) {
+q->enqueue(new ThreadRootsTask(p));
+}
+q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
+}
+// Used by Parallel Old
+void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
+ALL_JAVA_THREADS(p) {
+q->enqueue(new ThreadRootsMarkingTask(p));
+}
+q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
+}
+#endif // SERIALGC
+void Threads::nmethods_do() {
+ALL_JAVA_THREADS(p) {
+p->nmethods_do();
+}
+VMThread::vm_thread()->nmethods_do();
+}
+void Threads::gc_epilogue() {
+ALL_JAVA_THREADS(p) {
+p->gc_epilogue();
+}
+}
+void Threads::gc_prologue() {
+ALL_JAVA_THREADS(p) {
+p->gc_prologue();
+}
+}
+void Threads::deoptimized_wrt_marked_nmethods() {
+ALL_JAVA_THREADS(p) {
+p->deoptimized_wrt_marked_nmethods();
+}
+}
+// Get count Java threads that are waiting to enter the specified monitor.
+GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
+address monitor, bool doLock) {
+assert(doLock || SafepointSynchronize::is_at_safepoint(),
+"must grab Threads_lock or be at safepoint");
+GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
+int i = 0;
+{
+MutexLockerEx ml(doLock ? Threads_lock : NULL);
+ALL_JAVA_THREADS(p) {
+if (p->is_Compiler_thread()) continue;
+address pending = (address)p->current_pending_monitor();
+if (pending == monitor) {             // found a match
+if (i < count) result->append(p);   // save the first count matches
+i++;
+}
+}
+}
+return result;
+}
+JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
+assert(doLock ||
+Threads_lock->owned_by_self() ||
+SafepointSynchronize::is_at_safepoint(),
+"must grab Threads_lock or be at safepoint");
+// NULL owner means not locked so we can skip the search
+if (owner == NULL) return NULL;
+{
+MutexLockerEx ml(doLock ? Threads_lock : NULL);
+ALL_JAVA_THREADS(p) {
+// first, see if owner is the address of a Java thread
+if (owner == (address)p) return p;
+}
+}
+assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
+if (UseHeavyMonitors) return NULL;
+//
+// If we didn't find a matching Java thread and we didn't force use of
+// heavyweight monitors, then the owner is the stack address of the
+// Lock Word in the owning Java thread's stack.
+//
+// We can't use Thread::is_lock_owned() or Thread::lock_is_in_stack() because
+// those routines rely on the "current" stack pointer. That would be our
+// stack pointer which is not relevant to the question. Instead we use the
+// highest lock ever entered by the thread and find the thread that is
+// higher than and closest to our target stack address.
+//
+address    least_diff = 0;
+bool       least_diff_initialized = false;
+JavaThread* the_owner = NULL;
+{
+MutexLockerEx ml(doLock ? Threads_lock : NULL);
+ALL_JAVA_THREADS(q) {
+address addr = q->highest_lock();
+if (addr == NULL || addr < owner) continue;  // thread has entered no monitors or is too low
+address diff = (address)(addr - owner);
+if (!least_diff_initialized || diff < least_diff) {
+least_diff_initialized = true;
+least_diff = diff;
+the_owner = q;
+}
+}
+}
+assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
+return the_owner;
+}
+// Threads::print_on() is called at safepoint by VM_PrintThreads operation.
+void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
+char buf[32];
+st->print_cr(os::local_time_string(buf, sizeof(buf)));
+st->print_cr("Full thread dump %s (%s %s):",
+Abstract_VM_Version::vm_name(),
+Abstract_VM_Version::vm_release(),
+Abstract_VM_Version::vm_info_string()
+);
+st->cr();
+#ifndef SERIALGC
+// Dump concurrent locks
+ConcurrentLocksDump concurrent_locks;
+if (print_concurrent_locks) {
+concurrent_locks.dump_at_safepoint();
+}
+#endif // SERIALGC
+ALL_JAVA_THREADS(p) {
+ResourceMark rm;
+p->print_on(st);
+if (print_stacks) {
+if (internal_format) {
+p->trace_stack();
+} else {
+p->print_stack_on(st);
+}
+}
+st->cr();
+#ifndef SERIALGC
+if (print_concurrent_locks) {
+concurrent_locks.print_locks_on(p, st);
+}
+#endif // SERIALGC
+}
+VMThread::vm_thread()->print_on(st);
+st->cr();
+Universe::heap()->print_gc_threads_on(st);
+WatcherThread* wt = WatcherThread::watcher_thread();
+if (wt != NULL) wt->print_on(st);
+st->cr();
+CompileBroker::print_compiler_threads_on(st);
+st->flush();
+}
+// Threads::print_on_error() is called by fatal error handler. It's possible
+// that VM is not at safepoint and/or current thread is inside signal handler.
+// Don't print stack trace, as the stack may not be walkable. Don't allocate
+// memory (even in resource area), it might deadlock the error handler.
+void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
+bool found_current = false;
+st->print_cr("Java Threads: ( => current thread )");
+ALL_JAVA_THREADS(thread) {
+bool is_current = (current == thread);
+found_current = found_current || is_current;
+st->print("%s", is_current ? "=>" : "  ");
+st->print(PTR_FORMAT, thread);
+st->print(" ");
+thread->print_on_error(st, buf, buflen);
+st->cr();
+}
+st->cr();
+st->print_cr("Other Threads:");
+if (VMThread::vm_thread()) {
+bool is_current = (current == VMThread::vm_thread());
+found_current = found_current || is_current;
+st->print("%s", current == VMThread::vm_thread() ? "=>" : "  ");
+st->print(PTR_FORMAT, VMThread::vm_thread());
+st->print(" ");
+VMThread::vm_thread()->print_on_error(st, buf, buflen);
+st->cr();
+}
+WatcherThread* wt = WatcherThread::watcher_thread();
+if (wt != NULL) {
+bool is_current = (current == wt);
+found_current = found_current || is_current;
+st->print("%s", is_current ? "=>" : "  ");
+st->print(PTR_FORMAT, wt);
+st->print(" ");
+wt->print_on_error(st, buf, buflen);
+st->cr();
+}
+if (!found_current) {
+st->cr();
+st->print("=>" PTR_FORMAT " (exited) ", current);
+current->print_on_error(st, buf, buflen);
+st->cr();
+}
+}
+// Lifecycle management for TSM ParkEvents.
+// ParkEvents are type-stable (TSM).
+// In our particular implementation they happen to be immortal.
+//
+// We manage concurrency on the FreeList with a CAS-based
+// detach-modify-reattach idiom that avoids the ABA problems
+// that would otherwise be present in a simple CAS-based
+// push-pop implementation.   (push-one and pop-all)
+//
+// Caveat: Allocate() and Release() may be called from threads
+// other than the thread associated with the Event!
+// If we need to call Allocate() when running as the thread in
+// question then look for the PD calls to initialize native TLS.
+// Native TLS (Win32/Linux/Solaris) can only be initialized or
+// accessed by the associated thread.
+// See also pd_initialize().
+//
+// Note that we could defer associating a ParkEvent with a thread
+// until the 1st time the thread calls park().  unpark() calls to
+// an unprovisioned thread would be ignored.  The first park() call
+// for a thread would allocate and associate a ParkEvent and return
+// immediately.
+volatile int ParkEvent::ListLock = 0 ;
+ParkEvent * volatile ParkEvent::FreeList = NULL ;
+ParkEvent * ParkEvent::Allocate (Thread * t) {
+// In rare cases -- JVM_RawMonitor* operations -- we can find t == null.
+ParkEvent * ev ;
+// Start by trying to recycle an existing but unassociated
+// ParkEvent from the global free list.
+for (;;) {
+ev = FreeList ;
+if (ev == NULL) break ;
+// 1: Detach - sequester or privatize the list
+// Tantamount to ev = Swap (&FreeList, NULL)
+if (Atomic::cmpxchg_ptr (NULL, &FreeList, ev) != ev) {
+continue ;
+}
+// We've detached the list.  The list in-hand is now
+// local to this thread.   This thread can operate on the
+// list without risk of interference from other threads.
+// 2: Extract -- pop the 1st element from the list.
+ParkEvent * List = ev->FreeNext ;
+if (List == NULL) break ;
+for (;;) {
+// 3: Try to reattach the residual list
+guarantee (List != NULL, "invariant") ;
+ParkEvent * Arv =  (ParkEvent *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ;
+if (Arv == NULL) break ;
+// New nodes arrived.  Try to detach the recent arrivals.
+if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) {
+continue ;
+}
+guarantee (Arv != NULL, "invariant") ;
+// 4: Merge Arv into List
+ParkEvent * Tail = List ;
+while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ;
+Tail->FreeNext = Arv ;
+}
+break ;
+}
+if (ev != NULL) {
+guarantee (ev->AssociatedWith == NULL, "invariant") ;
+} else {
+// Do this the hard way -- materialize a new ParkEvent.
+// In rare cases an allocating thread might detach a long list --
+// installing null into FreeList -- and then stall or be obstructed.
+// A 2nd thread calling Allocate() would see FreeList == null.
+// The list held privately by the 1st thread is unavailable to the 2nd thread.
+// In that case the 2nd thread would have to materialize a new ParkEvent,
+// even though free ParkEvents existed in the system.  In this case we end up
+// with more ParkEvents in circulation than we need, but the race is
+// rare and the outcome is benign.  Ideally, the # of extant ParkEvents
+// is equal to the maximum # of threads that existed at any one time.
+// Because of the race mentioned above, segments of the freelist
+// can be transiently inaccessible.  At worst we may end up with the
+// # of ParkEvents in circulation slightly above the ideal.
+// Note that if we didn't have the TSM/immortal constraint, then
+// when reattaching, above, we could trim the list.
+ev = new ParkEvent () ;
+guarantee ((intptr_t(ev) & 0xFF) == 0, "invariant") ;
+}
+ev->reset() ;                     // courtesy to caller
+ev->AssociatedWith = t ;          // Associate ev with t
+ev->FreeNext       = NULL ;
+return ev ;
+}
+void ParkEvent::Release (ParkEvent * ev) {
+if (ev == NULL) return ;
+guarantee (ev->FreeNext == NULL      , "invariant") ;
+ev->AssociatedWith = NULL ;
+for (;;) {
+// Push ev onto FreeList
+// The mechanism is "half" lock-free.
+ParkEvent * List = FreeList ;
+ev->FreeNext = List ;
+if (Atomic::cmpxchg_ptr (ev, &FreeList, List) == List) break ;
+}
+}
+// Override operator new and delete so we can ensure that the
+// least significant byte of ParkEvent addresses is 0.
+// Beware that excessive address alignment is undesirable
+// as it can result in D$ index usage imbalance as
+// well as bank access imbalance on Niagara-like platforms,
+// although Niagara's hash function should help.
+void * ParkEvent::operator new (size_t sz) {
+return (void *) ((intptr_t (CHeapObj::operator new (sz + 256)) + 256) & -256) ;
+}
+void ParkEvent::operator delete (void * a) {
+// ParkEvents are type-stable and immortal ...
+ShouldNotReachHere();
+}
+// 6399321 As a temporary measure we copied & modified the ParkEvent::
+// allocate() and release() code for use by Parkers.  The Parker:: forms
+// will eventually be removed as we consolide and shift over to ParkEvents
+// for both builtin synchronization and JSR166 operations.
+volatile int Parker::ListLock = 0 ;
+Parker * volatile Parker::FreeList = NULL ;
+Parker * Parker::Allocate (JavaThread * t) {
+guarantee (t != NULL, "invariant") ;
+Parker * p ;
+// Start by trying to recycle an existing but unassociated
+// Parker from the global free list.
+for (;;) {
+p = FreeList ;
+if (p  == NULL) break ;
+// 1: Detach
+// Tantamount to p = Swap (&FreeList, NULL)
+if (Atomic::cmpxchg_ptr (NULL, &FreeList, p) != p) {
+continue ;
+}
+// We've detached the list.  The list in-hand is now
+// local to this thread.   This thread can operate on the
+// list without risk of interference from other threads.
+// 2: Extract -- pop the 1st element from the list.
+Parker * List = p->FreeNext ;
+if (List == NULL) break ;
+for (;;) {
+// 3: Try to reattach the residual list
+guarantee (List != NULL, "invariant") ;
+Parker * Arv =  (Parker *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ;
+if (Arv == NULL) break ;
+// New nodes arrived.  Try to detach the recent arrivals.
+if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) {
+continue ;
+}
+guarantee (Arv != NULL, "invariant") ;
+// 4: Merge Arv into List
+Parker * Tail = List ;
+while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ;
+Tail->FreeNext = Arv ;
+}
+break ;
+}
+if (p != NULL) {
+guarantee (p->AssociatedWith == NULL, "invariant") ;
+} else {
+// Do this the hard way -- materialize a new Parker..
+// In rare cases an allocating thread might detach
+// a long list -- installing null into FreeList --and
+// then stall.  Another thread calling Allocate() would see
+// FreeList == null and then invoke the ctor.  In this case we
+// end up with more Parkers in circulation than we need, but
+// the race is rare and the outcome is benign.
+// Ideally, the # of extant Parkers is equal to the
+// maximum # of threads that existed at any one time.
+// Because of the race mentioned above, segments of the
+// freelist can be transiently inaccessible.  At worst
+// we may end up with the # of Parkers in circulation
+// slightly above the ideal.
+p = new Parker() ;
+}
+p->AssociatedWith = t ;          // Associate p with t
+p->FreeNext       = NULL ;
+return p ;
+}
+void Parker::Release (Parker * p) {
+if (p == NULL) return ;
+guarantee (p->AssociatedWith != NULL, "invariant") ;
+guarantee (p->FreeNext == NULL      , "invariant") ;
+p->AssociatedWith = NULL ;
+for (;;) {
+// Push p onto FreeList
+Parker * List = FreeList ;
+p->FreeNext = List ;
+if (Atomic::cmpxchg_ptr (p, &FreeList, List) == List) break ;
+}
+}
+void Threads::verify() {
+ALL_JAVA_THREADS(p) {
+p->verify();
+}
+VMThread* thread = VMThread::vm_thread();
+if (thread != NULL) thread->verify();
+}

Mercurial > hg > truffle

comparison src/share/vm/runtime/thread.cpp @ 0:a61af66fc99e jdk7-b24