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android / toolchain / jdk / jdk21 / HEAD / . / src / hotspot / share / runtime / javaThread.cpp
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/*
* Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2021, Azul Systems, 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#include "cds/dynamicArchive.hpp"
#include "ci/ciEnv.hpp"
#include "classfile/javaClasses.inline.hpp"
#include "classfile/javaThreadStatus.hpp"
#include "classfile/systemDictionary.hpp"
#include "classfile/vmClasses.hpp"
#include "classfile/vmSymbols.hpp"
#include "code/codeCache.hpp"
#include "code/scopeDesc.hpp"
#include "compiler/compileTask.hpp"
#include "compiler/compilerThread.hpp"
#include "gc/shared/oopStorage.hpp"
#include "gc/shared/oopStorageSet.hpp"
#include "gc/shared/tlab_globals.hpp"
#include "jfr/jfrEvents.hpp"
#include "jvm.h"
#include "jvmtifiles/jvmtiEnv.hpp"
#include "logging/log.hpp"
#include "logging/logAsyncWriter.hpp"
#include "logging/logStream.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/iterator.hpp"
#include "memory/universe.hpp"
#include "oops/access.inline.hpp"
#include "oops/instanceKlass.hpp"
#include "oops/klass.inline.hpp"
#include "oops/oop.inline.hpp"
#include "oops/oopHandle.inline.hpp"
#include "oops/verifyOopClosure.hpp"
#include "prims/jvm_misc.hpp"
#include "prims/jvmtiDeferredUpdates.hpp"
#include "prims/jvmtiExport.hpp"
#include "prims/jvmtiThreadState.inline.hpp"
#include "runtime/atomic.hpp"
#include "runtime/continuation.hpp"
#include "runtime/continuationEntry.inline.hpp"
#include "runtime/continuationHelper.inline.hpp"
#include "runtime/deoptimization.hpp"
#include "runtime/frame.inline.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/handshake.hpp"
#include "runtime/interfaceSupport.inline.hpp"
#include "runtime/java.hpp"
#include "runtime/javaCalls.hpp"
#include "runtime/javaThread.inline.hpp"
#include "runtime/jniHandles.inline.hpp"
#include "runtime/lockStack.inline.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/orderAccess.hpp"
#include "runtime/osThread.hpp"
#include "runtime/safepoint.hpp"
#include "runtime/safepointMechanism.inline.hpp"
#include "runtime/safepointVerifiers.hpp"
#include "runtime/serviceThread.hpp"
#include "runtime/stackFrameStream.inline.hpp"
#include "runtime/stackWatermarkSet.hpp"
#include "runtime/synchronizer.hpp"
#include "runtime/threadCritical.hpp"
#include "runtime/threadSMR.inline.hpp"
#include "runtime/threadStatisticalInfo.hpp"
#include "runtime/threadWXSetters.inline.hpp"
#include "runtime/timer.hpp"
#include "runtime/timerTrace.hpp"
#include "runtime/vframe.inline.hpp"
#include "runtime/vframeArray.hpp"
#include "runtime/vframe_hp.hpp"
#include "runtime/vmThread.hpp"
#include "runtime/vmOperations.hpp"
#include "services/threadService.hpp"
#include "utilities/copy.hpp"
#include "utilities/defaultStream.hpp"
#include "utilities/dtrace.hpp"
#include "utilities/events.hpp"
#include "utilities/macros.hpp"
#include "utilities/preserveException.hpp"
#include "utilities/spinYield.hpp"
#include "utilities/vmError.hpp"
#if INCLUDE_JVMCI
#include "jvmci/jvmci.hpp"
#include "jvmci/jvmciEnv.hpp"
#endif
#if INCLUDE_JFR
#include "jfr/jfr.hpp"
#endif
// Set by os layer.
size_t JavaThread::_stack_size_at_create = 0;
#ifdef DTRACE_ENABLED
// Only bother with this argument setup if dtrace is available
#define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
#define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
#define DTRACE_THREAD_PROBE(probe, javathread) \
{ \
ResourceMark rm(this); \
int len = 0; \
const char* name = (javathread)->name(); \
len = strlen(name); \
HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
(char *) name, len, \
java_lang_Thread::thread_id((javathread)->threadObj()), \
(uintptr_t) (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
void JavaThread::smr_delete() {
if (_on_thread_list) {
ThreadsSMRSupport::smr_delete(this);
} else {
delete this;
}
}
// Initialized by VMThread at vm_global_init
OopStorage* JavaThread::_thread_oop_storage = nullptr;
OopStorage* JavaThread::thread_oop_storage() {
assert(_thread_oop_storage != nullptr, "not yet initialized");
return _thread_oop_storage;
}
void JavaThread::set_threadOopHandles(oop p) {
assert(_thread_oop_storage != nullptr, "not yet initialized");
_threadObj = OopHandle(_thread_oop_storage, p);
_vthread = OopHandle(_thread_oop_storage, p);
_jvmti_vthread = OopHandle(_thread_oop_storage, p->is_a(vmClasses::BoundVirtualThread_klass()) ? p : nullptr);
_scopedValueCache = OopHandle(_thread_oop_storage, nullptr);
}
oop JavaThread::threadObj() const {
// Ideally we would verify the current thread is oop_safe when this is called, but as we can
// be called from a signal handler we would have to use Thread::current_or_null_safe(). That
// has overhead and also interacts poorly with GetLastError on Windows due to the use of TLS.
// Instead callers must verify oop safe access.
return _threadObj.resolve();
}
oop JavaThread::vthread() const {
return _vthread.resolve();
}
void JavaThread::set_vthread(oop p) {
assert(_thread_oop_storage != nullptr, "not yet initialized");
_vthread.replace(p);
}
oop JavaThread::jvmti_vthread() const {
return _jvmti_vthread.resolve();
}
void JavaThread::set_jvmti_vthread(oop p) {
assert(_thread_oop_storage != nullptr, "not yet initialized");
_jvmti_vthread.replace(p);
}
oop JavaThread::scopedValueCache() const {
return _scopedValueCache.resolve();
}
void JavaThread::set_scopedValueCache(oop p) {
if (_scopedValueCache.ptr_raw() != nullptr) { // i.e. if the OopHandle has been allocated
_scopedValueCache.replace(p);
} else {
assert(p == nullptr, "not yet initialized");
}
}
void JavaThread::clear_scopedValueBindings() {
set_scopedValueCache(nullptr);
oop vthread_oop = vthread();
// vthread may be null here if we get a VM error during startup,
// before the java.lang.Thread instance has been created.
if (vthread_oop != nullptr) {
java_lang_Thread::clear_scopedValueBindings(vthread_oop);
}
}
void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
bool daemon, TRAPS) {
assert(thread_group.not_null(), "thread group should be specified");
assert(threadObj() == nullptr, "should only create Java thread object once");
InstanceKlass* ik = vmClasses::Thread_klass();
assert(ik->is_initialized(), "must be");
instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
// We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
// We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
// constructor calls Thread.current(), which must be set here.
java_lang_Thread::set_thread(thread_oop(), this);
set_threadOopHandles(thread_oop());
JavaValue result(T_VOID);
if (thread_name != nullptr) {
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,
ik,
vmSymbols::object_initializer_name(),
vmSymbols::threadgroup_string_void_signature(),
thread_group,
name,
CHECK);
} 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,
ik,
vmSymbols::object_initializer_name(),
vmSymbols::threadgroup_runnable_void_signature(),
thread_group,
Handle(),
CHECK);
}
os::set_priority(this, NormPriority);
if (daemon) {
java_lang_Thread::set_daemon(thread_oop());
}
}
// ======= JavaThread ========
#if INCLUDE_JVMCI
jlong* JavaThread::_jvmci_old_thread_counters;
bool jvmci_counters_include(JavaThread* thread) {
return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
}
void JavaThread::collect_counters(jlong* array, int length) {
assert(length == JVMCICounterSize, "wrong value");
for (int i = 0; i < length; i++) {
array[i] = _jvmci_old_thread_counters[i];
}
for (JavaThread* tp : ThreadsListHandle()) {
if (jvmci_counters_include(tp)) {
for (int i = 0; i < length; i++) {
array[i] += tp->_jvmci_counters[i];
}
}
}
}
// Attempt to enlarge the array for per thread counters.
jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
if (new_counters == nullptr) {
return nullptr;
}
if (old_counters == nullptr) {
old_counters = new_counters;
memset(old_counters, 0, sizeof(jlong) * new_size);
} else {
for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
new_counters[i] = old_counters[i];
}
if (new_size > current_size) {
memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
}
FREE_C_HEAP_ARRAY(jlong, old_counters);
}
return new_counters;
}
// Attempt to enlarge the array for per thread counters.
bool JavaThread::resize_counters(int current_size, int new_size) {
jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
if (new_counters == nullptr) {
return false;
} else {
_jvmci_counters = new_counters;
return true;
}
}
class VM_JVMCIResizeCounters : public VM_Operation {
private:
int _new_size;
bool _failed;
public:
VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
bool allow_nested_vm_operations() const { return true; }
void doit() {
// Resize the old thread counters array
jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
if (new_counters == nullptr) {
_failed = true;
return;
} else {
JavaThread::_jvmci_old_thread_counters = new_counters;
}
// Now resize each threads array
for (JavaThread* tp : ThreadsListHandle()) {
if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
_failed = true;
break;
}
}
if (!_failed) {
JVMCICounterSize = _new_size;
}
}
bool failed() { return _failed; }
};
bool JavaThread::resize_all_jvmci_counters(int new_size) {
VM_JVMCIResizeCounters op(new_size);
VMThread::execute(&op);
return !op.failed();
}
#endif // INCLUDE_JVMCI
#ifdef ASSERT
// Checks safepoint allowed and clears unhandled oops at potential safepoints.
void JavaThread::check_possible_safepoint() {
if (_no_safepoint_count > 0) {
print_owned_locks();
assert(false, "Possible safepoint reached by thread that does not allow it");
}
#ifdef CHECK_UNHANDLED_OOPS
// Clear unhandled oops in JavaThreads so we get a crash right away.
clear_unhandled_oops();
#endif // CHECK_UNHANDLED_OOPS
// Macos/aarch64 should be in the right state for safepoint (e.g.
// deoptimization needs WXWrite). Crashes caused by the wrong state rarely
// happens in practice, making such issues hard to find and reproduce.
#if defined(__APPLE__) && defined(AARCH64)
if (AssertWXAtThreadSync) {
assert_wx_state(WXWrite);
}
#endif
}
void JavaThread::check_for_valid_safepoint_state() {
// Don't complain if running a debugging command.
if (DebuggingContext::is_enabled()) return;
// Check NoSafepointVerifier, which is implied by locks taken that can be
// shared with the VM thread. This makes sure that no locks with allow_vm_block
// are held.
check_possible_safepoint();
if (thread_state() != _thread_in_vm) {
fatal("LEAF method calling lock?");
}
if (GCALotAtAllSafepoints) {
// We could enter a safepoint here and thus have a gc
InterfaceSupport::check_gc_alot();
}
}
#endif // ASSERT
// A JavaThread is a normal Java thread
JavaThread::JavaThread() :
// Initialize fields
_on_thread_list(false),
DEBUG_ONLY(_java_call_counter(0) COMMA)
_entry_point(nullptr),
_deopt_mark(nullptr),
_deopt_nmethod(nullptr),
_vframe_array_head(nullptr),
_vframe_array_last(nullptr),
_jvmti_deferred_updates(nullptr),
_callee_target(nullptr),
_vm_result(nullptr),
_vm_result_2(nullptr),
_current_pending_monitor(nullptr),
_current_pending_monitor_is_from_java(true),
_current_waiting_monitor(nullptr),
_active_handles(nullptr),
_free_handle_block(nullptr),
_Stalled(0),
_monitor_chunks(nullptr),
_suspend_flags(0),
_thread_state(_thread_new),
_saved_exception_pc(nullptr),
#ifdef ASSERT
_no_safepoint_count(0),
_visited_for_critical_count(false),
#endif
_terminated(_not_terminated),
_in_deopt_handler(0),
_doing_unsafe_access(false),
_do_not_unlock_if_synchronized(false),
#if INCLUDE_JVMTI
_carrier_thread_suspended(false),
_is_in_VTMS_transition(false),
_is_in_tmp_VTMS_transition(false),
#ifdef ASSERT
_is_VTMS_transition_disabler(false),
#endif
#endif
_jni_attach_state(_not_attaching_via_jni),
#if INCLUDE_JVMCI
_pending_deoptimization(-1),
_pending_monitorenter(false),
_pending_transfer_to_interpreter(false),
_in_retryable_allocation(false),
_pending_failed_speculation(0),
_jvmci{nullptr},
_libjvmci_runtime(nullptr),
_jvmci_counters(nullptr),
_jvmci_reserved0(0),
_jvmci_reserved1(0),
_jvmci_reserved_oop0(nullptr),
#endif // INCLUDE_JVMCI
_exception_oop(oop()),
_exception_pc(0),
_exception_handler_pc(0),
_is_method_handle_return(0),
_jni_active_critical(0),
_pending_jni_exception_check_fn(nullptr),
_depth_first_number(0),
// JVMTI PopFrame support
_popframe_condition(popframe_inactive),
_frames_to_pop_failed_realloc(0),
_cont_entry(nullptr),
_cont_fastpath(0),
_cont_fastpath_thread_state(1),
_held_monitor_count(0),
_jni_monitor_count(0),
_handshake(this),
_popframe_preserved_args(nullptr),
_popframe_preserved_args_size(0),
_jvmti_thread_state(nullptr),
_interp_only_mode(0),
_should_post_on_exceptions_flag(JNI_FALSE),
_thread_stat(new ThreadStatistics()),
_parker(),
_class_to_be_initialized(nullptr),
_SleepEvent(ParkEvent::Allocate(this)),
_lock_stack(this) {
set_jni_functions(jni_functions());
#if INCLUDE_JVMCI
assert(_jvmci._implicit_exception_pc == nullptr, "must be");
if (JVMCICounterSize > 0) {
resize_counters(0, (int) JVMCICounterSize);
}
#endif // INCLUDE_JVMCI
// Setup safepoint state info for this thread
ThreadSafepointState::create(this);
SafepointMechanism::initialize_header(this);
set_requires_cross_modify_fence(false);
pd_initialize();
assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
}
JavaThread::JavaThread(bool is_attaching_via_jni) : JavaThread() {
if (is_attaching_via_jni) {
_jni_attach_state = _attaching_via_jni;
}
}
// interrupt support
void JavaThread::interrupt() {
// All callers should have 'this' thread protected by a
// ThreadsListHandle so that it cannot terminate and deallocate
// itself.
debug_only(check_for_dangling_thread_pointer(this);)
// For Windows _interrupt_event
WINDOWS_ONLY(osthread()->set_interrupted(true);)
// For Thread.sleep
_SleepEvent->unpark();
// For JSR166 LockSupport.park
parker()->unpark();
// For ObjectMonitor and JvmtiRawMonitor
_ParkEvent->unpark();
}
bool JavaThread::is_interrupted(bool clear_interrupted) {
debug_only(check_for_dangling_thread_pointer(this);)
if (_threadObj.peek() == nullptr) {
// If there is no j.l.Thread then it is impossible to have
// been interrupted. We can find null during VM initialization
// or when a JNI thread is still in the process of attaching.
// In such cases this must be the current thread.
assert(this == Thread::current(), "invariant");
return false;
}
bool interrupted = java_lang_Thread::interrupted(threadObj());
// NOTE that since there is no "lock" around the interrupt and
// is_interrupted operations, there is the possibility that the
// interrupted flag will be "false" but that the
// low-level events will be in the signaled state. This is
// intentional. The effect of this is that Object.wait() and
// LockSupport.park() will appear to have a spurious wakeup, which
// is allowed and not harmful, and the possibility is so rare that
// it is not worth the added complexity to add yet another lock.
// For the sleep event an explicit reset is performed on entry
// to JavaThread::sleep, so there is no early return. It has also been
// recommended not to put the interrupted flag into the "event"
// structure because it hides the issue.
// Also, because there is no lock, we must only clear the interrupt
// state if we are going to report that we were interrupted; otherwise
// an interrupt that happens just after we read the field would be lost.
if (interrupted && clear_interrupted) {
assert(this == Thread::current(), "only the current thread can clear");
java_lang_Thread::set_interrupted(threadObj(), false);
WINDOWS_ONLY(osthread()->set_interrupted(false);)
}
return interrupted;
}
void JavaThread::block_if_vm_exited() {
if (_terminated == _vm_exited) {
// _vm_exited is set at safepoint, and Threads_lock is never released
// so we will block here forever.
// Here we can be doing a jump from a safe state to an unsafe state without
// proper transition, but it happens after the final safepoint has begun so
// this jump won't cause any safepoint problems.
set_thread_state(_thread_in_vm);
Threads_lock->lock();
ShouldNotReachHere();
}
}
JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : JavaThread() {
_jni_attach_state = _not_attaching_via_jni;
set_entry_point(entry_point);
// Create the native thread itself.
// %note runtime_23
os::ThreadType thr_type = os::java_thread;
thr_type = entry_point == &CompilerThread::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() {
// Enqueue OopHandles for release by the service thread.
add_oop_handles_for_release();
// Return the sleep event to the free list
ParkEvent::Release(_SleepEvent);
_SleepEvent = nullptr;
// Free any remaining previous UnrollBlock
vframeArray* old_array = vframe_array_last();
if (old_array != nullptr) {
Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
old_array->set_unroll_block(nullptr);
delete old_info;
delete old_array;
}
JvmtiDeferredUpdates* updates = deferred_updates();
if (updates != nullptr) {
// This can only happen if thread is destroyed before deoptimization occurs.
assert(updates->count() > 0, "Updates holder not deleted");
// free deferred updates.
delete updates;
set_deferred_updates(nullptr);
}
// All Java related clean up happens in exit
ThreadSafepointState::destroy(this);
if (_thread_stat != nullptr) delete _thread_stat;
#if INCLUDE_JVMCI
if (JVMCICounterSize > 0) {
FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
}
#endif // INCLUDE_JVMCI
}
// First JavaThread specific code executed by a new Java thread.
void JavaThread::pre_run() {
// empty - see comments in run()
}
// The main routine called by a new Java thread. This isn't overridden
// by subclasses, instead different subclasses define a different "entry_point"
// which defines the actual logic for that kind of thread.
void JavaThread::run() {
// initialize thread-local alloc buffer related fields
initialize_tlab();
_stack_overflow_state.create_stack_guard_pages();
cache_global_variables();
// Thread is now sufficiently initialized to be handled by the safepoint code as being
// in the VM. Change thread state from _thread_new to _thread_in_vm
assert(this->thread_state() == _thread_new, "wrong thread state");
set_thread_state(_thread_in_vm);
// Before a thread is on the threads list it is always safe, so after leaving the
// _thread_new we should emit a instruction barrier. The distance to modified code
// from here is probably far enough, but this is consistent and safe.
OrderAccess::cross_modify_fence();
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.
set_active_handles(JNIHandleBlock::allocate_block());
if (JvmtiExport::should_post_thread_life()) {
JvmtiExport::post_thread_start(this);
}
if (AlwaysPreTouchStacks) {
pretouch_stack();
}
// 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();
}
void JavaThread::thread_main_inner() {
assert(JavaThread::current() == this, "sanity check");
assert(_threadObj.peek() != nullptr, "just checking");
// Execute thread entry point unless this thread has a pending exception.
// Note: Due to JVMTI StopThread we can have pending exceptions already!
if (!this->has_pending_exception()) {
{
ResourceMark rm(this);
this->set_native_thread_name(this->name());
}
HandleMark hm(this);
this->entry_point()(this, this);
}
DTRACE_THREAD_PROBE(stop, this);
// Cleanup is handled in post_run()
}
// Shared teardown for all JavaThreads
void JavaThread::post_run() {
this->exit(false);
this->unregister_thread_stack_with_NMT();
// Defer deletion to here to ensure 'this' is still referenceable in call_run
// for any shared tear-down.
this->smr_delete();
}
static void ensure_join(JavaThread* thread) {
// We do not need to grab 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);
// Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
// Clear the native thread instance - this makes isAlive return false and allows the join()
// to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
// requirements.
java_lang_Thread::release_set_thread(threadObj(), nullptr);
lock.notify_all(thread);
// Ignore pending exception, since we are exiting anyway
thread->clear_pending_exception();
}
static bool is_daemon(oop threadObj) {
return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
}
// 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");
assert(!is_exiting(), "should not be exiting or terminated already");
elapsedTimer _timer_exit_phase1;
elapsedTimer _timer_exit_phase2;
elapsedTimer _timer_exit_phase3;
elapsedTimer _timer_exit_phase4;
if (log_is_enabled(Debug, os, thread, timer)) {
_timer_exit_phase1.start();
}
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 (!destroy_vm) {
if (uncaught_exception.not_null()) {
EXCEPTION_MARK;
// Call method Thread.dispatchUncaughtException().
Klass* thread_klass = vmClasses::Thread_klass();
JavaValue result(T_VOID);
JavaCalls::call_virtual(&result,
threadObj, thread_klass,
vmSymbols::dispatchUncaughtException_name(),
vmSymbols::throwable_void_signature(),
uncaught_exception,
THREAD);
if (HAS_PENDING_EXCEPTION) {
ResourceMark rm(this);
jio_fprintf(defaultStream::error_stream(),
"\nException: %s thrown from the UncaughtExceptionHandler"
" in thread \"%s\"\n",
pending_exception()->klass()->external_name(),
name());
CLEAR_PENDING_EXCEPTION;
}
}
if (!is_Compiler_thread()) {
// We have finished executing user-defined Java code and now have to do the
// implementation specific clean-up by calling Thread.exit(). We prevent any
// asynchronous exceptions from being delivered while in Thread.exit()
// to ensure the clean-up is not corrupted.
NoAsyncExceptionDeliveryMark _no_async(this);
EXCEPTION_MARK;
JavaValue result(T_VOID);
Klass* thread_klass = vmClasses::Thread_klass();
JavaCalls::call_virtual(&result,
threadObj, thread_klass,
vmSymbols::exit_method_name(),
vmSymbols::void_method_signature(),
THREAD);
CLEAR_PENDING_EXCEPTION;
}
// notify JVMTI
if (JvmtiExport::should_post_thread_life()) {
JvmtiExport::post_thread_end(this);
}
} else {
// before_exit() has already posted JVMTI THREAD_END events
}
// Cleanup any pending async exception now since we cannot access oops after
// BarrierSet::barrier_set()->on_thread_detach() has been executed.
if (has_async_exception_condition()) {
handshake_state()->clean_async_exception_operation();
}
// The careful dance between thread suspension and exit is handled here.
// Since we are in thread_in_vm state and suspension is done with handshakes,
// we can just put in the exiting state and it will be correctly handled.
// Also, no more async exceptions will be added to the queue after this point.
set_terminated(_thread_exiting);
ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
if (log_is_enabled(Debug, os, thread, timer)) {
_timer_exit_phase1.stop();
_timer_exit_phase2.start();
}
// Capture daemon status before the thread is marked as terminated.
bool daemon = is_daemon(threadObj());
// 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");
if (log_is_enabled(Debug, os, thread, timer)) {
_timer_exit_phase2.stop();
_timer_exit_phase3.start();
}
// 6282335 JNI DetachCurrentThread spec states that all Java monitors
// held by this thread must be released. The spec does not distinguish
// between JNI-acquired and regular Java monitors. We can only see
// regular Java monitors here if monitor enter-exit matching is broken.
//
// ensure_join() ignores IllegalThreadStateExceptions, and so does
// ObjectSynchronizer::release_monitors_owned_by_thread().
if (exit_type == jni_detach) {
// Sanity check even though JNI DetachCurrentThread() would have
// returned JNI_ERR if there was a Java frame. JavaThread exit
// should be done executing Java code by the time we get here.
assert(!this->has_last_Java_frame(),
"should not have a Java frame when detaching or exiting");
ObjectSynchronizer::release_monitors_owned_by_thread(this);
assert(!this->has_pending_exception(), "release_monitors should have cleared");
}
// Since above code may not release JNI monitors and if someone forgot to do an
// JNI monitorexit, held count should be equal jni count.
// Consider scan all object monitor for this owner if JNI count > 0 (at least on detach).
assert(this->held_monitor_count() == this->jni_monitor_count(),
"held monitor count should be equal to jni: " INT64_FORMAT " != " INT64_FORMAT,
(int64_t)this->held_monitor_count(), (int64_t)this->jni_monitor_count());
if (CheckJNICalls && this->jni_monitor_count() > 0) {
// We would like a fatal here, but due to we never checked this before there
// is a lot of tests which breaks, even with an error log.
log_debug(jni)("JavaThread %s (tid: " UINTX_FORMAT ") with Objects still locked by JNI MonitorEnter.",
exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
}
// 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
JFR_ONLY(Jfr::on_thread_exit(this);)
if (active_handles() != nullptr) {
JNIHandleBlock* block = active_handles();
set_active_handles(nullptr);
JNIHandleBlock::release_block(block);
}
if (free_handle_block() != nullptr) {
JNIHandleBlock* block = free_handle_block();
set_free_handle_block(nullptr);
JNIHandleBlock::release_block(block);
}
// These have to be removed while this is still a valid thread.
_stack_overflow_state.remove_stack_guard_pages();
if (UseTLAB) {
tlab().retire();
}
if (JvmtiEnv::environments_might_exist()) {
JvmtiExport::cleanup_thread(this);
}
// We need to cache the thread name for logging purposes below as once
// we have called on_thread_detach this thread must not access any oops.
char* thread_name = nullptr;
if (log_is_enabled(Debug, os, thread, timer)) {
ResourceMark rm(this);
thread_name = os::strdup(name());
}
log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
os::current_thread_id());
if (log_is_enabled(Debug, os, thread, timer)) {
_timer_exit_phase3.stop();
_timer_exit_phase4.start();
}
#if INCLUDE_JVMCI
if (JVMCICounterSize > 0) {
if (jvmci_counters_include(this)) {
for (int i = 0; i < JVMCICounterSize; i++) {
_jvmci_old_thread_counters[i] += _jvmci_counters[i];
}
}
}
#endif // INCLUDE_JVMCI
// Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
// We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
Threads::remove(this, daemon);
if (log_is_enabled(Debug, os, thread, timer)) {
_timer_exit_phase4.stop();
log_debug(os, thread, timer)("name='%s'"
", exit-phase1=" JLONG_FORMAT
", exit-phase2=" JLONG_FORMAT
", exit-phase3=" JLONG_FORMAT
", exit-phase4=" JLONG_FORMAT,
thread_name,
_timer_exit_phase1.milliseconds(),
_timer_exit_phase2.milliseconds(),
_timer_exit_phase3.milliseconds(),
_timer_exit_phase4.milliseconds());
os::free(thread_name);
}
}
void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
if (active_handles() != nullptr) {
JNIHandleBlock* block = active_handles();
set_active_handles(nullptr);
JNIHandleBlock::release_block(block);
}
if (free_handle_block() != nullptr) {
JNIHandleBlock* block = free_handle_block();
set_free_handle_block(nullptr);
JNIHandleBlock::release_block(block);
}
// These have to be removed while this is still a valid thread.
_stack_overflow_state.remove_stack_guard_pages();
if (UseTLAB) {
tlab().retire();
}
Threads::remove(this, is_daemon);
this->smr_delete();
}
JavaThread* JavaThread::active() {
Thread* thread = Thread::current();
if (thread->is_Java_thread()) {
return JavaThread::cast(thread);
} else {
assert(thread->is_VM_thread(), "this must be a vm thread");
VM_Operation* op = ((VMThread*) thread)->vm_operation();
JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
return ret;
}
}
bool JavaThread::is_lock_owned(address adr) const {
assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
if (Thread::is_lock_owned(adr)) return true;
for (MonitorChunk* chunk = monitor_chunks(); chunk != nullptr; chunk = chunk->next()) {
if (chunk->contains(adr)) return true;
}
return false;
}
oop JavaThread::exception_oop() const {
return Atomic::load(&_exception_oop);
}
void JavaThread::set_exception_oop(oop o) {
Atomic::store(&_exception_oop, o);
}
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() != nullptr, "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());
}
}
void JavaThread::handle_special_runtime_exit_condition() {
if (is_obj_deopt_suspend()) {
frame_anchor()->make_walkable();
wait_for_object_deoptimization();
}
JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
}
// Asynchronous exceptions support
//
void JavaThread::handle_async_exception(oop java_throwable) {
assert(java_throwable != nullptr, "should have an _async_exception to throw");
assert(!is_at_poll_safepoint(), "should have never called this method");
if (has_last_Java_frame()) {
frame f = last_frame();
if (f.is_runtime_frame()) {
// 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.
RegisterMap reg_map(this,
RegisterMap::UpdateMap::skip,
RegisterMap::ProcessFrames::include,
RegisterMap::WalkContinuation::skip);
frame compiled_frame = f.sender(&reg_map);
if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
Deoptimization::deoptimize(this, compiled_frame);
}
}
}
// We cannot call Exceptions::_throw(...) here because we cannot block
set_pending_exception(java_throwable, __FILE__, __LINE__);
clear_scopedValueBindings();
LogTarget(Info, exceptions) lt;
if (lt.is_enabled()) {
ResourceMark rm;
LogStream ls(lt);
ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
if (has_last_Java_frame()) {
frame f = last_frame();
ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
}
ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
}
}
void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
// Do not throw asynchronous exceptions against the compiler thread
// or if the thread is already exiting.
if (!can_call_java() || is_exiting()) {
delete aeh;
return;
}
oop exception = aeh->exception();
Handshake::execute(aeh, this); // Install asynchronous handshake
ResourceMark rm;
if (log_is_enabled(Info, exceptions)) {
log_info(exceptions)("Pending Async. exception installed of type: %s",
InstanceKlass::cast(exception->klass())->external_name());
}
// for AbortVMOnException flag
Exceptions::debug_check_abort(exception->klass()->external_name());
oop vt_oop = vthread();
if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
// Interrupt thread so it will wake up from a potential wait()/sleep()/park()
java_lang_Thread::set_interrupted(threadObj(), true);
this->interrupt();
}
}
class InstallAsyncExceptionHandshake : public HandshakeClosure {
AsyncExceptionHandshake* _aeh;
public:
InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
~InstallAsyncExceptionHandshake() {
// If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh.
delete _aeh;
}
void do_thread(Thread* thr) {
JavaThread* target = JavaThread::cast(thr);
target->install_async_exception(_aeh);
_aeh = nullptr;
}
};
void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
OopHandle e(Universe::vm_global(), java_throwable);
InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
Handshake::execute(&iaeh, target);
}
#if INCLUDE_JVMTI
void JavaThread::set_is_in_VTMS_transition(bool val) {
_is_in_VTMS_transition = val;
}
#ifdef ASSERT
void JavaThread::set_is_VTMS_transition_disabler(bool val) {
_is_VTMS_transition_disabler = val;
}
#endif
#endif
// External suspension mechanism.
//
// Guarantees on return (for a valid target thread):
// - Target thread will not execute any new bytecode.
// - Target thread will not enter any new monitors.
//
bool JavaThread::java_suspend() {
#if INCLUDE_JVMTI
// Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
#endif
guarantee(Thread::is_JavaThread_protected(/* target */ this),
"target JavaThread is not protected in calling context.");
return this->handshake_state()->suspend();
}
bool JavaThread::java_resume() {
guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
"missing ThreadsListHandle in calling context.");
return this->handshake_state()->resume();
}
// Wait for another thread to perform object reallocation and relocking on behalf of
// this thread. The current thread is required to change to _thread_blocked in order
// to be seen to be safepoint/handshake safe whilst suspended and only after becoming
// handshake safe, the other thread can complete the handshake used to synchronize
// with this thread and then perform the reallocation and relocking.
// See EscapeBarrier::sync_and_suspend_*()
void JavaThread::wait_for_object_deoptimization() {
assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
assert(this == Thread::current(), "invariant");
bool spin_wait = os::is_MP();
do {
ThreadBlockInVM tbivm(this, true /* allow_suspend */);
// Wait for object deoptimization if requested.
if (spin_wait) {
// A single deoptimization is typically very short. Microbenchmarks
// showed 5% better performance when spinning.
const uint spin_limit = 10 * SpinYield::default_spin_limit;
SpinYield spin(spin_limit);
for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
spin.wait();
}
// Spin just once
spin_wait = false;
} else {
MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
if (is_obj_deopt_suspend()) {
ml.wait();
}
}
// A handshake for obj. deoptimization suspend could have been processed so
// we must check after processing.
} while (is_obj_deopt_suspend());
}
#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() {
// Cannot create a ThreadsListHandle here and check !tlh.includes(this)
// since an unpublished JavaThread doesn't participate in the
// Thread-SMR protocol for keeping a ThreadsList alive.
assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
}
#endif
// Slow path when the native==>Java barriers detect a safepoint/handshake is
// pending, when _suspend_flags is non-zero or when we need to process a stack
// watermark. Also check for pending async exceptions (except unsafe access error).
// Note only the native==>Java barriers can call this function when thread state
// is _thread_in_native_trans.
void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
thread->set_thread_state(_thread_in_vm);
// Enable WXWrite: called directly from interpreter native wrapper.
MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
// After returning from native, it could be that the stack frames are not
// yet safe to use. We catch such situations in the subsequent stack watermark
// barrier, which will trap unsafe stack frames.
StackWatermarkSet::before_unwind(thread);
}
#ifndef PRODUCT
// Deoptimization
// Function for testing deoptimization
void JavaThread::deoptimize() {
StackFrameStream fst(this, false /* update */, true /* process_frames */);
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 != nullptr) {
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());
}
}
if (DebugDeoptimization && deopt) {
tty->print_cr("[AFTER Deoptimization]");
trace_frames();
}
}
// Make zombies
void JavaThread::make_zombies() {
for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !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::deoptimize_marked_methods() {
if (!has_last_Java_frame()) return;
StackFrameStream fst(this, false /* update */, true /* process_frames */);
for (; !fst.is_done(); fst.next()) {
if (fst.current()->should_be_deoptimized()) {
Deoptimization::deoptimize(this, *fst.current());
}
}
}
#ifdef ASSERT
void JavaThread::verify_frame_info() {
assert((!has_last_Java_frame() && java_call_counter() == 0) ||
(has_last_Java_frame() && java_call_counter() > 0),
"unexpected frame info: has_last_frame=%s, java_call_counter=%d",
has_last_Java_frame() ? "true" : "false", java_call_counter());
}
#endif
// Push on a new block of JNI handles.
void JavaThread::push_jni_handle_block() {
// Allocate a new block for JNI handles.
// Inlined code from jni_PushLocalFrame()
JNIHandleBlock* old_handles = active_handles();
JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
set_active_handles(new_handles);
}
// Pop off the current block of JNI handles.
void JavaThread::pop_jni_handle_block() {
// Release our JNI handle block
JNIHandleBlock* old_handles = active_handles();
JNIHandleBlock* new_handles = old_handles->pop_frame_link();
assert(new_handles != nullptr, "should never set active handles to null");
set_active_handles(new_handles);
old_handles->set_pop_frame_link(nullptr);
JNIHandleBlock::release_block(old_handles, this);
}
void JavaThread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
// Verify that the deferred card marks have been flushed.
assert(deferred_card_mark().is_empty(), "Should be empty during GC");
// Traverse the GCHandles
Thread::oops_do_no_frames(f, cf);
if (active_handles() != nullptr) {
active_handles()->oops_do(f);
}
DEBUG_ONLY(verify_frame_info();)
if (has_last_Java_frame()) {
// Traverse the monitor chunks
for (MonitorChunk* chunk = monitor_chunks(); chunk != nullptr; chunk = chunk->next()) {
chunk->oops_do(f);
}
}
assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
// If we have deferred set_locals there might be oops waiting to be
// written
GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
if (list != nullptr) {
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*) &_vm_result);
f->do_oop((oop*) &_exception_oop);
#if INCLUDE_JVMCI
f->do_oop((oop*) &_jvmci_reserved_oop0);
#endif
if (jvmti_thread_state() != nullptr) {
jvmti_thread_state()->oops_do(f, cf);
}
// The continuation oops are really on the stack. But there is typically at most
// one of those per thread, so we handle them here in the oops_do_no_frames part
// so that we don't have to sprinkle as many stack watermark checks where these
// oops are used. We just need to make sure the thread has started processing.
ContinuationEntry* entry = _cont_entry;
while (entry != nullptr) {
f->do_oop((oop*)entry->cont_addr());
f->do_oop((oop*)entry->chunk_addr());
entry = entry->parent();
}
if (LockingMode == LM_LIGHTWEIGHT) {
lock_stack().oops_do(f);
}
}
void JavaThread::oops_do_frames(OopClosure* f, CodeBlobClosure* cf) {
if (!has_last_Java_frame()) {
return;
}
// Finish any pending lazy GC activity for the frames
StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
// Traverse the execution stack
for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
fst.current()->oops_do(f, cf, fst.register_map());
}
}
#ifdef ASSERT
void JavaThread::verify_states_for_handshake() {
// This checks that the thread has a correct frame state during a handshake.
verify_frame_info();
}
#endif
void JavaThread::nmethods_do(CodeBlobClosure* cf) {
DEBUG_ONLY(verify_frame_info();)
MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
if (has_last_Java_frame()) {
// Traverse the execution stack
for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
fst.current()->nmethods_do(cf);
}
}
if (jvmti_thread_state() != nullptr) {
jvmti_thread_state()->nmethods_do(cf);
}
}
void JavaThread::metadata_do(MetadataClosure* f) {
if (has_last_Java_frame()) {
// Traverse the execution stack to call f() on the methods in the stack
for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
fst.current()->metadata_do(f);
}
} else if (is_Compiler_thread()) {
// need to walk ciMetadata in current compile tasks to keep alive.
CompilerThread* ct = (CompilerThread*)this;
if (ct->env() != nullptr) {
ct->env()->metadata_do(f);
}
CompileTask* task = ct->task();
if (task != nullptr) {
task->metadata_do(f);
}
}
}
// 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";
}
}
void JavaThread::print_thread_state_on(outputStream *st) const {
st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
}
// Called by Threads::print() for VM_PrintThreads operation
void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
st->print_raw("\"");
st->print_raw(name());
st->print_raw("\" ");
oop thread_oop = threadObj();
if (thread_oop != nullptr) {
st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
}
Thread::print_on(st, print_extended_info);
// print guess for valid stack memory region (assume 4K pages); helps lock debugging
st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
if (thread_oop != nullptr) {
if (is_vthread_mounted()) {
oop vt = vthread();
assert(vt != nullptr, "");
st->print_cr(" Carrying virtual thread #" INT64_FORMAT, (int64_t)java_lang_Thread::thread_id(vt));
} else {
st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
}
}
#ifndef PRODUCT
_safepoint_state->print_on(st);
#endif // PRODUCT
if (is_Compiler_thread()) {
CompileTask *task = ((CompilerThread*)this)->task();
if (task != nullptr) {
st->print(" Compiling: ");
task->print(st, nullptr, true, false);
} else {
st->print(" No compile task");
}
st->cr();
}
}
void JavaThread::print() const { print_on(tty); }
void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
st->print("%s", get_thread_name_string(buf, buflen));
}
// 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("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
Thread* current = Thread::current_or_null_safe();
assert(current != nullptr, "cannot be called by a detached thread");
st->fill_to(60);
if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
// Only access threadObj() if current thread is not a JavaThread
// or if it is a JavaThread that can safely access oops.
oop thread_obj = threadObj();
if (thread_obj != nullptr) {
st->print(java_lang_Thread::is_daemon(thread_obj) ? " 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 ") (" PROPERFMT ")",
p2i(stack_end()), p2i(stack_base()),
PROPERFMTARGS(stack_size()));
st->print("]");
ThreadsSMRSupport::print_info_on(this, st);
return;
}
// Verification
void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
// ignore if there is no stack
if (!has_last_Java_frame()) return;
// traverse the stack frames. Starts from top frame.
for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
frame* fr = fst.current();
f(fr, fst.register_map());
}
}
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, nullptr);
// 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 its threadObj set (e.g., 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::name() const {
if (Thread::is_JavaThread_protected(/* target */ this)) {
// The target JavaThread is protected so get_thread_name_string() is safe:
return get_thread_name_string();
}
// The target JavaThread is not protected so we return the default:
return Thread::name();
}
// Like name() but doesn't include the protection check. This must only be
// called when it is known to be safe, even though the protection check can't tell
// that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
const char* JavaThread::name_raw() const {
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;
#ifdef ASSERT
Thread* current = Thread::current_or_null_safe();
assert(current != nullptr, "cannot be called by a detached thread");
if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
// Only access threadObj() if current thread is not a JavaThread
// or if it is a JavaThread that can safely access oops.
#endif
oop thread_obj = threadObj();
if (thread_obj != nullptr) {
oop name = java_lang_Thread::name(thread_obj);
if (name != nullptr) {
if (buf == nullptr) {
name_str = java_lang_String::as_utf8_string(name);
} else {
name_str = java_lang_String::as_utf8_string(name, buf, buflen);
}
} else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
name_str = "<no-name - thread is attaching>";
} else {
name_str = "<un-named>";
}
} else {
name_str = Thread::name();
}
#ifdef ASSERT
} else {
// Current JavaThread has exited...
if (current == this) {
// ... and is asking about itself:
name_str = "<no-name - current JavaThread has exited>";
} else {
// ... and it can't safely determine this JavaThread's name so
// use the default thread name.
name_str = Thread::name();
}
}
#endif
assert(name_str != nullptr, "unexpected null thread name");
return name_str;
}
// Helper to extract the name from the thread oop for logging.
const char* JavaThread::name_for(oop thread_obj) {
assert(thread_obj != nullptr, "precondition");
oop name = java_lang_Thread::name(thread_obj);
const char* name_str;
if (name != nullptr) {
name_str = java_lang_String::as_utf8_string(name);
} else {
name_str = "<un-named>";
}
return name_str;
}
void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
// 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_threadOopHandles(thread_oop());
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);
// Publish the JavaThread* in java.lang.Thread after the JavaThread* is
// on a ThreadsList. We don't want to wait for the release when the
// Theads_lock is dropped somewhere in the caller since the JavaThread*
// is already visible to JVM/TI via the ThreadsList.
java_lang_Thread::release_set_thread(thread_oop(), this);
}
oop JavaThread::current_park_blocker() {
// Support for JSR-166 locks
oop thread_oop = threadObj();
if (thread_oop != nullptr) {
return java_lang_Thread::park_blocker(thread_oop);
}
return nullptr;
}
// Print current stack trace for checked JNI warnings and JNI fatal errors.
// This is the external format, selecting the platform or vthread
// as applicable, and allowing for a native-only stack.
void JavaThread::print_jni_stack() {
assert(this == JavaThread::current(), "Can't print stack of other threads");
if (!has_last_Java_frame()) {
ResourceMark rm(this);
char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
if (buf == nullptr) {
tty->print_cr("Unable to print native stack - out of memory");
return;
}
frame f = os::current_frame();
VMError::print_native_stack(tty, f, this, true /*print_source_info */,
-1 /* max stack */, buf, O_BUFLEN);
} else {
print_active_stack_on(tty);
}
}
void JavaThread::print_stack_on(outputStream* st) {
if (!has_last_Java_frame()) return;
Thread* current_thread = Thread::current();
ResourceMark rm(current_thread);
HandleMark hm(current_thread);
RegisterMap reg_map(this,
RegisterMap::UpdateMap::include,
RegisterMap::ProcessFrames::include,
RegisterMap::WalkContinuation::skip);
vframe* start_vf = platform_thread_last_java_vframe(&reg_map);
int count = 0;
for (vframe* f = start_vf; f != nullptr; 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 if MaxJavaStackTraceDepth > 0
count++;
if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
}
}
void JavaThread::print_vthread_stack_on(outputStream* st) {
assert(is_vthread_mounted(), "Caller should have checked this");
assert(has_last_Java_frame(), "must be");
Thread* current_thread = Thread::current();
ResourceMark rm(current_thread);
HandleMark hm(current_thread);
RegisterMap reg_map(this,
RegisterMap::UpdateMap::include,
RegisterMap::ProcessFrames::include,
RegisterMap::WalkContinuation::include);
ContinuationEntry* cont_entry = last_continuation();
vframe* start_vf = last_java_vframe(&reg_map);
int count = 0;
for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
// Watch for end of vthread stack
if (Continuation::is_continuation_enterSpecial(f->fr())) {
assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
if (cont_entry->is_virtual_thread()) {
break;
}
cont_entry = cont_entry->parent();
}
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 if MaxJavaStackTraceDepth > 0
count++;
if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
}
}
void JavaThread::print_active_stack_on(outputStream* st) {
if (is_vthread_mounted()) {
print_vthread_stack_on(st);
} else {
print_stack_on(st);
}
}
#if INCLUDE_JVMTI
// Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
set_jvmti_vthread(thread_oop);
// unbind current JvmtiThreadState from JavaThread
JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
// bind new JvmtiThreadState to JavaThread
JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
return jvmti_thread_state();
}
#endif
// JVMTI PopFrame support
void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
assert(_popframe_preserved_args == nullptr, "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), mtThread);
_popframe_preserved_args_size = in_bytes(size_in_bytes);
Copy::conjoint_jbytes(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 != nullptr, "should not free PopFrame preserved arguments twice");
FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
_popframe_preserved_args = nullptr;
_popframe_preserved_args_size = 0;
}
#ifndef PRODUCT
void JavaThread::trace_frames() {
tty->print_cr("[Describe stack]");
int frame_no = 1;
for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
tty->print(" %d. ", frame_no++);
fst.current()->print_value_on(tty, this);
tty->cr();
}
}
class PrintAndVerifyOopClosure: public OopClosure {
protected:
template <class T> inline void do_oop_work(T* p) {
oop obj = RawAccess<>::oop_load(p);
if (obj == nullptr) return;
tty->print(INTPTR_FORMAT ": ", p2i(p));
if (oopDesc::is_oop_or_null(obj)) {
if (obj->is_objArray()) {
tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
} else {
obj->print();
}
} else {
tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
}
tty->cr();
}
public:
virtual void do_oop(oop* p) { do_oop_work(p); }
virtual void do_oop(narrowOop* p) { do_oop_work(p); }
};
#ifdef ASSERT
// Print or validate the layout of stack frames
void JavaThread::print_frame_layout(int depth, bool validate_only) {
ResourceMark rm;
PreserveExceptionMark pm(this);
FrameValues values;
int frame_no = 0;
for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
fst.current()->describe(values, ++frame_no, fst.register_map());
if (depth == frame_no) break;
}
Continuation::describe(values);
if (validate_only) {
values.validate();
} else {
tty->print_cr("[Describe stack layout]");
values.print(this);
}
}
#endif
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;
Thread* current_thread = Thread::current();
ResourceMark rm(current_thread);
HandleMark hm(current_thread);
RegisterMap reg_map(this,
RegisterMap::UpdateMap::include,
RegisterMap::ProcessFrames::include,
RegisterMap::WalkContinuation::skip);
trace_stack_from(last_java_vframe(&reg_map));
}
#endif // PRODUCT
void JavaThread::inc_held_monitor_count(int i, bool jni) {
#ifdef SUPPORT_MONITOR_COUNT
assert(_held_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_held_monitor_count);
_held_monitor_count += i;
if (jni) {
assert(_jni_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_jni_monitor_count);
_jni_monitor_count += i;
}
#endif
}
void JavaThread::dec_held_monitor_count(int i, bool jni) {
#ifdef SUPPORT_MONITOR_COUNT
_held_monitor_count -= i;
assert(_held_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_held_monitor_count);
if (jni) {
_jni_monitor_count -= i;
assert(_jni_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_jni_monitor_count);
}
#endif
}
frame JavaThread::vthread_last_frame() {
assert (is_vthread_mounted(), "Virtual thread not mounted");
return last_frame();
}
frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
const ContinuationEntry* entry = vthread_continuation();
guarantee (entry != nullptr, "Not a carrier thread");
frame f = entry->to_frame();
if (reg_map->process_frames()) {
entry->flush_stack_processing(this);
}
entry->update_register_map(reg_map);
return f.sender(reg_map);
}
frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
}
javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
assert(reg_map != nullptr, "a map must be given");
for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
if (vf->is_java_frame()) return javaVFrame::cast(vf);
}
return nullptr;
}
Klass* JavaThread::security_get_caller_class(int depth) {
ResetNoHandleMark rnhm;
HandleMark hm(Thread::current());
vframeStream vfst(this);
vfst.security_get_caller_frame(depth);
if (!vfst.at_end()) {
return vfst.method()->method_holder();
}
return nullptr;
}
// Internal convenience function for millisecond resolution sleeps.
bool JavaThread::sleep(jlong millis) {
jlong nanos;
if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
// Conversion to nanos would overflow, saturate at max
nanos = max_jlong;
} else {
nanos = millis * NANOUNITS_PER_MILLIUNIT;
}
return sleep_nanos(nanos);
}
// java.lang.Thread.sleep support
// Returns true if sleep time elapsed as expected, and false
// if the thread was interrupted.
bool JavaThread::sleep_nanos(jlong nanos) {
assert(this == Thread::current(), "thread consistency check");
assert(nanos >= 0, "nanos are in range");
ParkEvent * const slp = this->_SleepEvent;
// Because there can be races with thread interruption sending an unpark()
// to the event, we explicitly reset it here to avoid an immediate return.
// The actual interrupt state will be checked before we park().
slp->reset();
// Thread interruption establishes a happens-before ordering in the
// Java Memory Model, so we need to ensure we synchronize with the
// interrupt state.
OrderAccess::fence();
jlong prevtime = os::javaTimeNanos();
jlong nanos_remaining = nanos;
for (;;) {
// interruption has precedence over timing out
if (this->is_interrupted(true)) {
return false;
}
if (nanos_remaining <= 0) {
return true;
}
{
ThreadBlockInVM tbivm(this);
OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
slp->park_nanos(nanos_remaining);
}
// Update elapsed time tracking
jlong newtime = os::javaTimeNanos();
if (newtime - prevtime < 0) {
// time moving backwards, should only happen if no monotonic clock
// not a guarantee() because JVM should not abort on kernel/glibc bugs
assert(false,
"unexpected time moving backwards detected in JavaThread::sleep()");
} else {
nanos_remaining -= (newtime - prevtime);
}
prevtime = newtime;
}
}
// 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;
Klass* shutdown_klass =
SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
THREAD);
if (shutdown_klass != nullptr) {
// 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
// won't be run. Note that if a shutdown hook was registered,
// the Shutdown class would have already been loaded
// (Runtime.addShutdownHook will load it).
JavaValue result(T_VOID);
JavaCalls::call_static(&result,
shutdown_klass,
vmSymbols::shutdown_name(),
vmSymbols::void_method_signature(),
THREAD);
}
CLEAR_PENDING_EXCEPTION;
}
#ifndef PRODUCT
void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
}
#endif
// Helper function to create the java.lang.Thread object for a
// VM-internal thread. The thread will have the given name, and be
// a member of the "system" ThreadGroup.
Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
Handle string = java_lang_String::create_from_str(name, CHECK_NH);
// Initialize thread_oop to put it into the system threadGroup.
// This is done by calling the Thread(ThreadGroup group, String name) constructor.
Handle thread_group(THREAD, Universe::system_thread_group());
Handle thread_oop =
JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
vmSymbols::threadgroup_string_void_signature(),
thread_group,
string,
CHECK_NH);
return thread_oop;
}
// Starts the target JavaThread as a daemon of the given priority, and
// bound to the given java.lang.Thread instance.
// The Threads_lock is held for the duration.
void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
Handle thread_oop, ThreadPriority prio) {
assert(target->osthread() != nullptr, "target thread is not properly initialized");
MutexLocker mu(current, Threads_lock);
// Initialize the fields of the thread_oop first.
if (prio != NoPriority) {
java_lang_Thread::set_priority(thread_oop(), prio);
// Note: we don't call os::set_priority here. Possibly we should,
// else all threads should call it themselves when they first run.
}
java_lang_Thread::set_daemon(thread_oop());
// Now bind the thread_oop to the target JavaThread.
target->set_threadOopHandles(thread_oop());
Threads::add(target); // target is now visible for safepoint/handshake
// Publish the JavaThread* in java.lang.Thread after the JavaThread* is
// on a ThreadsList. We don't want to wait for the release when the
// Theads_lock is dropped when the 'mu' destructor is run since the
// JavaThread* is already visible to JVM/TI via the ThreadsList.
java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
Thread::start(target);
}
void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
// At this point it may be possible that no osthread was created for the
// JavaThread due to lack of resources. However, since this must work
// for critical system threads just check and abort if this fails.
if (thread->osthread() == nullptr) {
// This isn't really an OOM condition, but historically this is what
// we report.
vm_exit_during_initialization("java.lang.OutOfMemoryError",
os::native_thread_creation_failed_msg());
}
}
void JavaThread::pretouch_stack() {
// Given an established java thread stack with usable area followed by
// shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
// from the current frame down to the start of the shadow zone.
const address end = _stack_overflow_state.shadow_zone_safe_limit();
if (is_in_full_stack(end)) {
char* p1 = (char*) alloca(1);
address here = (address) &p1;
if (is_in_full_stack(here) && here > end) {
size_t to_alloc = here - end;
char* p2 = (char*) alloca(to_alloc);
log_trace(os, thread)("Pretouching thread stack from " PTR_FORMAT " to " PTR_FORMAT ".",
p2i(p2), p2i(end));
os::pretouch_memory(p2, p2 + to_alloc,
NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
}
}
}
// Deferred OopHandle release support.
class OopHandleList : public CHeapObj<mtInternal> {
static const int _count = 4;
OopHandle _handles[_count];
OopHandleList* _next;
int _index;
public:
OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
void add(OopHandle h) {
assert(_index < _count, "too many additions");
_handles[_index++] = h;
}
~OopHandleList() {
assert(_index == _count, "usage error");
for (int i = 0; i < _index; i++) {
_handles[i].release(JavaThread::thread_oop_storage());
}
}
OopHandleList* next() const { return _next; }
};
OopHandleList* JavaThread::_oop_handle_list = nullptr;
// Called by the ServiceThread to do the work of releasing
// the OopHandles.
void JavaThread::release_oop_handles() {
OopHandleList* list;
{
MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
list = _oop_handle_list;
_oop_handle_list = nullptr;
}
assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
while (list != nullptr) {
OopHandleList* l = list;
list = l->next();
delete l;
}
}
// Add our OopHandles for later release.
void JavaThread::add_oop_handles_for_release() {
MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
OopHandleList* new_head = new OopHandleList(_oop_handle_list);
new_head->add(_threadObj);
new_head->add(_vthread);
new_head->add(_jvmti_vthread);
new_head->add(_scopedValueCache);
_oop_handle_list = new_head;
Service_lock->notify_all();
}