1 /*
2 * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "cds/cds_globals.hpp"
28 #include "cds/metaspaceShared.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/javaClasses.hpp"
31 #include "classfile/javaThreadStatus.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "classfile/vmClasses.hpp"
34 #include "classfile/vmSymbols.hpp"
35 #include "compiler/compileBroker.hpp"
36 #include "compiler/compileTask.hpp"
37 #include "compiler/compilerThread.hpp"
38 #include "gc/shared/barrierSet.hpp"
39 #include "gc/shared/barrierSetNMethod.hpp"
40 #include "gc/shared/gcVMOperations.hpp"
41 #include "gc/shared/oopStorage.hpp"
42 #include "gc/shared/oopStorageSet.hpp"
43 #include "gc/shared/stringdedup/stringDedup.hpp"
44 #include "jfr/jfrEvents.hpp"
45 #include "jvm.h"
46 #include "jvmtifiles/jvmtiEnv.hpp"
47 #include "logging/log.hpp"
48 #include "logging/logAsyncWriter.hpp"
49 #include "logging/logConfiguration.hpp"
50 #include "memory/allocation.inline.hpp"
51 #include "memory/iterator.hpp"
52 #include "memory/oopFactory.hpp"
53 #include "memory/resourceArea.hpp"
54 #include "memory/universe.hpp"
55 #include "oops/instanceKlass.hpp"
56 #include "oops/klass.inline.hpp"
57 #include "oops/oop.inline.hpp"
58 #include "oops/symbol.hpp"
59 #include "prims/jvmtiAgentList.hpp"
60 #include "prims/jvm_misc.hpp"
61 #include "runtime/arguments.hpp"
62 #include "runtime/fieldDescriptor.inline.hpp"
63 #include "runtime/flags/jvmFlagLimit.hpp"
64 #include "runtime/handles.inline.hpp"
65 #include "runtime/globals.hpp"
66 #include "runtime/interfaceSupport.inline.hpp"
67 #include "runtime/java.hpp"
68 #include "runtime/javaCalls.hpp"
69 #include "runtime/javaThread.inline.hpp"
70 #include "runtime/jniHandles.inline.hpp"
71 #include "runtime/jniPeriodicChecker.hpp"
72 #include "runtime/lockStack.inline.hpp"
73 #include "runtime/monitorDeflationThread.hpp"
74 #include "runtime/mutexLocker.hpp"
75 #include "runtime/nonJavaThread.hpp"
76 #include "runtime/objectMonitor.inline.hpp"
77 #include "runtime/osThread.hpp"
78 #include "runtime/safepoint.hpp"
79 #include "runtime/safepointMechanism.inline.hpp"
80 #include "runtime/safepointVerifiers.hpp"
81 #include "runtime/serviceThread.hpp"
82 #include "runtime/sharedRuntime.hpp"
83 #include "runtime/statSampler.hpp"
84 #include "runtime/stubCodeGenerator.hpp"
85 #include "runtime/thread.inline.hpp"
86 #include "runtime/threads.hpp"
87 #include "runtime/threadSMR.inline.hpp"
88 #include "runtime/timer.hpp"
89 #include "runtime/timerTrace.hpp"
90 #include "runtime/trimNativeHeap.hpp"
91 #include "runtime/vmOperations.hpp"
92 #include "runtime/vm_version.hpp"
93 #include "services/attachListener.hpp"
94 #include "services/management.hpp"
95 #include "services/memTracker.hpp"
96 #include "services/threadIdTable.hpp"
97 #include "services/threadService.hpp"
98 #include "utilities/dtrace.hpp"
99 #include "utilities/events.hpp"
100 #include "utilities/macros.hpp"
101 #include "utilities/vmError.hpp"
102 #if INCLUDE_JVMCI
103 #include "jvmci/jvmci.hpp"
104 #include "jvmci/jvmciEnv.hpp"
105 #endif
106 #ifdef COMPILER2
107 #include "opto/idealGraphPrinter.hpp"
108 #endif
109 #if INCLUDE_RTM_OPT
110 #include "runtime/rtmLocking.hpp"
111 #endif
112 #if INCLUDE_JFR
113 #include "jfr/jfr.hpp"
114 #endif
115
116 // Initialization after module runtime initialization
117 void universe_post_module_init(); // must happen after call_initPhase2
118
119
120 static void initialize_class(Symbol* class_name, TRAPS) {
121 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
122 InstanceKlass::cast(klass)->initialize(CHECK);
123 }
124
125
126 // Creates the initial ThreadGroup
127 static Handle create_initial_thread_group(TRAPS) {
128 Handle system_instance = JavaCalls::construct_new_instance(
129 vmClasses::ThreadGroup_klass(),
130 vmSymbols::void_method_signature(),
131 CHECK_NH);
132 Universe::set_system_thread_group(system_instance());
133
134 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
135 Handle main_instance = JavaCalls::construct_new_instance(
136 vmClasses::ThreadGroup_klass(),
137 vmSymbols::threadgroup_string_void_signature(),
138 system_instance,
139 string,
140 CHECK_NH);
141 return main_instance;
142 }
143
144 // Creates the initial Thread, and sets it to running.
145 static void create_initial_thread(Handle thread_group, JavaThread* thread,
146 TRAPS) {
147 InstanceKlass* ik = vmClasses::Thread_klass();
148 assert(ik->is_initialized(), "must be");
149 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
150
151 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
152 // constructor calls Thread.current(), which must be set here for the
153 // initial thread.
154 java_lang_Thread::set_thread(thread_oop(), thread);
155 thread->set_threadOopHandles(thread_oop());
156
157 Handle string = java_lang_String::create_from_str("main", CHECK);
158
159 JavaValue result(T_VOID);
160 JavaCalls::call_special(&result, thread_oop,
161 ik,
162 vmSymbols::object_initializer_name(),
163 vmSymbols::threadgroup_string_void_signature(),
164 thread_group,
165 string,
166 CHECK);
167
168 // Set thread status to running since main thread has
169 // been started and running.
170 java_lang_Thread::set_thread_status(thread_oop(),
171 JavaThreadStatus::RUNNABLE);
172 }
173
174 // Extract version and vendor specific information from
175 // java.lang.VersionProps fields.
176 // Returned char* is allocated in the thread's resource area
177 // so must be copied for permanency.
178 static const char* get_java_version_info(InstanceKlass* ik,
179 Symbol* field_name) {
180 fieldDescriptor fd;
181 bool found = ik != nullptr &&
182 ik->find_local_field(field_name,
183 vmSymbols::string_signature(), &fd);
184 if (found) {
185 oop name_oop = ik->java_mirror()->obj_field(fd.offset());
186 if (name_oop == nullptr) {
187 return nullptr;
188 }
189 const char* name = java_lang_String::as_utf8_string(name_oop);
190 return name;
191 } else {
192 return nullptr;
193 }
194 }
195
196 // ======= Threads ========
197
198 // The Threads class links together all active threads, and provides
199 // operations over all threads. It is protected by the Threads_lock,
200 // which is also used in other global contexts like safepointing.
201 // ThreadsListHandles are used to safely perform operations on one
202 // or more threads without the risk of the thread exiting during the
203 // operation.
204 //
205 // Note: The Threads_lock is currently more widely used than we
206 // would like. We are actively migrating Threads_lock uses to other
207 // mechanisms in order to reduce Threads_lock contention.
208
209 int Threads::_number_of_threads = 0;
210 int Threads::_number_of_non_daemon_threads = 0;
211 int Threads::_return_code = 0;
212 uintx Threads::_thread_claim_token = 1; // Never zero.
213
214 #ifdef ASSERT
215 bool Threads::_vm_complete = false;
216 #endif
217
218 // General purpose hook into Java code, run once when the VM is initialized.
219 // The Java library method itself may be changed independently from the VM.
220 static void call_postVMInitHook(TRAPS) {
221 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
222 if (klass != nullptr) {
223 JavaValue result(T_VOID);
224 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
225 vmSymbols::void_method_signature(),
226 CHECK);
227 }
228 }
229
230 // All NonJavaThreads (i.e., every non-JavaThread in the system).
231 void Threads::non_java_threads_do(ThreadClosure* tc) {
232 NoSafepointVerifier nsv;
233 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
234 tc->do_thread(njti.current());
235 }
236 }
237
238 // All JavaThreads
239 #define ALL_JAVA_THREADS(X) \
240 for (JavaThread* X : *ThreadsSMRSupport::get_java_thread_list())
241
242 // All JavaThreads
243 void Threads::java_threads_do(ThreadClosure* tc) {
244 assert_locked_or_safepoint(Threads_lock);
245 // ALL_JAVA_THREADS iterates through all JavaThreads.
246 ALL_JAVA_THREADS(p) {
247 tc->do_thread(p);
248 }
249 }
250
251 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
252 void Threads::threads_do(ThreadClosure* tc) {
253 assert_locked_or_safepoint(Threads_lock);
254 java_threads_do(tc);
255 non_java_threads_do(tc);
256 }
257
258 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
259 assert_at_safepoint();
260
261 uintx claim_token = Threads::thread_claim_token();
262 ALL_JAVA_THREADS(p) {
263 if (p->claim_threads_do(is_par, claim_token)) {
264 tc->do_thread(p);
265 }
266 }
267 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
268 Thread* current = njti.current();
269 if (current->claim_threads_do(is_par, claim_token)) {
270 tc->do_thread(current);
271 }
272 }
273 }
274
275 // The system initialization in the library has three phases.
276 //
277 // Phase 1: java.lang.System class initialization
278 // java.lang.System is a primordial class loaded and initialized
279 // by the VM early during startup. java.lang.System.<clinit>
280 // only does registerNatives and keeps the rest of the class
281 // initialization work later until thread initialization completes.
282 //
283 // System.initPhase1 initializes the system properties, the static
284 // fields in, out, and err. Set up java signal handlers, OS-specific
285 // system settings, and thread group of the main thread.
286 static void call_initPhase1(TRAPS) {
287 Klass* klass = vmClasses::System_klass();
288 JavaValue result(T_VOID);
289 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
290 vmSymbols::void_method_signature(), CHECK);
291 }
292
293 // Phase 2. Module system initialization
294 // This will initialize the module system. Only java.base classes
295 // can be loaded until phase 2 completes.
296 //
297 // Call System.initPhase2 after the compiler initialization and jsr292
298 // classes get initialized because module initialization runs a lot of java
299 // code, that for performance reasons, should be compiled. Also, this will
300 // enable the startup code to use lambda and other language features in this
301 // phase and onward.
302 //
303 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
304 static void call_initPhase2(TRAPS) {
305 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
306
307 Klass* klass = vmClasses::System_klass();
308
309 JavaValue result(T_INT);
310 JavaCallArguments args;
311 args.push_int(DisplayVMOutputToStderr);
312 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
313 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
314 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
315 if (result.get_jint() != JNI_OK) {
316 vm_exit_during_initialization(); // no message or exception
317 }
318
319 universe_post_module_init();
320 }
321
322 // Phase 3. final setup - set security manager, system class loader and TCCL
323 //
324 // This will instantiate and set the security manager, set the system class
325 // loader as well as the thread context class loader. The security manager
326 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
327 // other modules or the application's classpath.
328 static void call_initPhase3(TRAPS) {
329 Klass* klass = vmClasses::System_klass();
330 JavaValue result(T_VOID);
331 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
332 vmSymbols::void_method_signature(), CHECK);
333 }
334
335 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
336 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
337
338 initialize_class(vmSymbols::java_lang_String(), CHECK);
339
340 // Inject CompactStrings value after the static initializers for String ran.
341 java_lang_String::set_compact_strings(CompactStrings);
342
343 // Initialize java_lang.System (needed before creating the thread)
344 initialize_class(vmSymbols::java_lang_System(), CHECK);
345 // The VM creates & returns objects of this class. Make sure it's initialized.
346 initialize_class(vmSymbols::java_lang_Class(), CHECK);
347 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
348 Handle thread_group = create_initial_thread_group(CHECK);
349 Universe::set_main_thread_group(thread_group());
350 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
351 create_initial_thread(thread_group, main_thread, CHECK);
352
353 // The VM creates objects of this class.
354 initialize_class(vmSymbols::java_lang_Module(), CHECK);
355
356 #ifdef ASSERT
357 InstanceKlass *k = vmClasses::UnsafeConstants_klass();
358 assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
359 #endif
360
361 // initialize the hardware-specific constants needed by Unsafe
362 initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
363 jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
364
365 // The VM preresolves methods to these classes. Make sure that they get initialized
366 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
367 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
368
369 // Phase 1 of the system initialization in the library, java.lang.System class initialization
370 call_initPhase1(CHECK);
371
372 // Get the Java runtime name, version, and vendor info after java.lang.System is initialized.
373 // Some values are actually configure-time constants but some can be set via the jlink tool and
374 // so must be read dynamically. We treat them all the same.
375 InstanceKlass* ik = SystemDictionary::find_instance_klass(THREAD, vmSymbols::java_lang_VersionProps(),
376 Handle(), Handle());
377 {
378 ResourceMark rm(main_thread);
379 JDK_Version::set_java_version(get_java_version_info(ik, vmSymbols::java_version_name()));
380
381 JDK_Version::set_runtime_name(get_java_version_info(ik, vmSymbols::java_runtime_name_name()));
382
383 JDK_Version::set_runtime_version(get_java_version_info(ik, vmSymbols::java_runtime_version_name()));
384
385 JDK_Version::set_runtime_vendor_version(get_java_version_info(ik, vmSymbols::java_runtime_vendor_version_name()));
386
387 JDK_Version::set_runtime_vendor_vm_bug_url(get_java_version_info(ik, vmSymbols::java_runtime_vendor_vm_bug_url_name()));
388 }
389
390 // an instance of OutOfMemory exception has been allocated earlier
391 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
392 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
393 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
394 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
395 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
396 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
397 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
398 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
399 }
400
401 void Threads::initialize_jsr292_core_classes(TRAPS) {
402 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
403
404 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
405 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
406 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
407 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
408 }
409
410 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
411 extern void JDK_Version_init();
412
413 // Preinitialize version info.
414 VM_Version::early_initialize();
415
416 // Check version
417 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
418
419 // Initialize library-based TLS
420 ThreadLocalStorage::init();
421
422 // Initialize the output stream module
423 ostream_init();
424
425 // Process java launcher properties.
426 Arguments::process_sun_java_launcher_properties(args);
427
428 // Initialize the os module
429 os::init();
430
431 MACOS_AARCH64_ONLY(os::current_thread_enable_wx(WXWrite));
432
433 // Record VM creation timing statistics
434 TraceVmCreationTime create_vm_timer;
435 create_vm_timer.start();
436
437 // Initialize system properties.
438 Arguments::init_system_properties();
439
440 // So that JDK version can be used as a discriminator when parsing arguments
441 JDK_Version_init();
442
443 // Update/Initialize System properties after JDK version number is known
444 Arguments::init_version_specific_system_properties();
445
446 // Make sure to initialize log configuration *before* parsing arguments
447 LogConfiguration::initialize(create_vm_timer.begin_time());
448
449 // Parse arguments
450 // Note: this internally calls os::init_container_support()
451 jint parse_result = Arguments::parse(args);
452 if (parse_result != JNI_OK) return parse_result;
453
454 // Initialize NMT right after argument parsing to keep the pre-NMT-init window small.
455 MemTracker::initialize();
456
457 os::init_before_ergo();
458
459 jint ergo_result = Arguments::apply_ergo();
460 if (ergo_result != JNI_OK) return ergo_result;
461
462 // Final check of all ranges after ergonomics which may change values.
463 if (!JVMFlagLimit::check_all_ranges()) {
464 return JNI_EINVAL;
465 }
466
467 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
468 bool constraint_result = JVMFlagLimit::check_all_constraints(JVMFlagConstraintPhase::AfterErgo);
469 if (!constraint_result) {
470 return JNI_EINVAL;
471 }
472
473 if (PauseAtStartup) {
474 os::pause();
475 }
476
477 HOTSPOT_VM_INIT_BEGIN();
478
479 // Timing (must come after argument parsing)
480 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
481
482 // Initialize the os module after parsing the args
483 jint os_init_2_result = os::init_2();
484 if (os_init_2_result != JNI_OK) return os_init_2_result;
485
486 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
487 // Initialize assert poison page mechanism.
488 if (ShowRegistersOnAssert) {
489 initialize_assert_poison();
490 }
491 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
492
493 SafepointMechanism::initialize();
494
495 jint adjust_after_os_result = Arguments::adjust_after_os();
496 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
497
498 // Initialize output stream logging
499 ostream_init_log();
500
501 // Launch -agentlib/-agentpath and converted -Xrun agents
502 JvmtiAgentList::load_agents();
503
504 // Initialize Threads state
505 _number_of_threads = 0;
506 _number_of_non_daemon_threads = 0;
507
508 // Initialize global data structures and create system classes in heap
509 vm_init_globals();
510
511 #if INCLUDE_JVMCI
512 if (JVMCICounterSize > 0) {
513 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
514 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
515 } else {
516 JavaThread::_jvmci_old_thread_counters = nullptr;
517 }
518 #endif // INCLUDE_JVMCI
519
520 // Initialize OopStorage for threadObj
521 JavaThread::_thread_oop_storage = OopStorageSet::create_strong("Thread OopStorage", mtThread);
522
523 // Attach the main thread to this os thread
524 JavaThread* main_thread = new JavaThread();
525 main_thread->set_thread_state(_thread_in_vm);
526 main_thread->initialize_thread_current();
527 // must do this before set_active_handles
528 main_thread->record_stack_base_and_size();
529 main_thread->register_thread_stack_with_NMT();
530 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
531 MACOS_AARCH64_ONLY(main_thread->init_wx());
532
533 if (!main_thread->set_as_starting_thread()) {
534 vm_shutdown_during_initialization(
535 "Failed necessary internal allocation. Out of swap space");
536 main_thread->smr_delete();
537 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
538 return JNI_ENOMEM;
539 }
540
541 // Enable guard page *after* os::create_main_thread(), otherwise it would
542 // crash Linux VM, see notes in os_linux.cpp.
543 main_thread->stack_overflow_state()->create_stack_guard_pages();
544
545 // Initialize Java-Level synchronization subsystem
546 ObjectMonitor::Initialize();
547 ObjectSynchronizer::initialize();
548
549 // Initialize global modules
550 jint status = init_globals();
551 if (status != JNI_OK) {
552 main_thread->smr_delete();
553 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
554 return status;
555 }
556
557 // Create WatcherThread as soon as we can since we need it in case
558 // of hangs during error reporting.
559 WatcherThread::start();
560
561 // Add main_thread to threads list to finish barrier setup with
562 // on_thread_attach. Should be before starting to build Java objects in
563 // init_globals2, which invokes barriers.
564 {
565 MutexLocker mu(Threads_lock);
566 Threads::add(main_thread);
567 }
568
569 status = init_globals2();
570 if (status != JNI_OK) {
571 Threads::remove(main_thread, false);
572 // It is possible that we managed to fully initialize Universe but have then
573 // failed by throwing an exception. In that case our caller JNI_CreateJavaVM
574 // will want to report it, so we can't delete the main thread.
575 if (!main_thread->has_pending_exception()) {
576 main_thread->smr_delete();
577 }
578 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
579 return status;
580 }
581
582 JFR_ONLY(Jfr::on_create_vm_1();)
583
584 // Should be done after the heap is fully created
585 main_thread->cache_global_variables();
586
587 // Any JVMTI raw monitors entered in onload will transition into
588 // real raw monitor. VM is setup enough here for raw monitor enter.
589 JvmtiExport::transition_pending_onload_raw_monitors();
590
591 // Create the VMThread
592 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
593
594 VMThread::create();
595 VMThread* vmthread = VMThread::vm_thread();
596
597 if (!os::create_thread(vmthread, os::vm_thread)) {
598 vm_exit_during_initialization("Cannot create VM thread. "
599 "Out of system resources.");
600 }
601
602 // Wait for the VM thread to become ready, and VMThread::run to initialize
603 // Monitors can have spurious returns, must always check another state flag
604 {
605 MonitorLocker ml(Notify_lock);
606 os::start_thread(vmthread);
607 while (!vmthread->is_running()) {
608 ml.wait();
609 }
610 }
611 }
612
613 assert(Universe::is_fully_initialized(), "not initialized");
614 if (VerifyDuringStartup) {
615 // Make sure we're starting with a clean slate.
616 VM_Verify verify_op;
617 VMThread::execute(&verify_op);
618 }
619
620 // We need this to update the java.vm.info property in case any flags used
621 // to initially define it have been changed. This is needed for both CDS
622 // since UseSharedSpaces may be changed after java.vm.info
623 // is initially computed. See Abstract_VM_Version::vm_info_string().
624 // This update must happen before we initialize the java classes, but
625 // after any initialization logic that might modify the flags.
626 Arguments::update_vm_info_property(VM_Version::vm_info_string());
627
628 JavaThread* THREAD = JavaThread::current(); // For exception macros.
629 HandleMark hm(THREAD);
630
631 // Always call even when there are not JVMTI environments yet, since environments
632 // may be attached late and JVMTI must track phases of VM execution
633 JvmtiExport::enter_early_start_phase();
634
635 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
636 JvmtiExport::post_early_vm_start();
637
638 // Launch -Xrun agents early if EagerXrunInit is set
639 if (EagerXrunInit) {
640 JvmtiAgentList::load_xrun_agents();
641 }
642
643 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
644
645 quicken_jni_functions();
646
647 // No more stub generation allowed after that point.
648 StubCodeDesc::freeze();
649
650 // Set flag that basic initialization has completed. Used by exceptions and various
651 // debug stuff, that does not work until all basic classes have been initialized.
652 set_init_completed();
653
654 LogConfiguration::post_initialize();
655 Metaspace::post_initialize();
656 MutexLocker::post_initialize();
657
658 HOTSPOT_VM_INIT_END();
659
660 // record VM initialization completion time
661 #if INCLUDE_MANAGEMENT
662 Management::record_vm_init_completed();
663 #endif // INCLUDE_MANAGEMENT
664
665 log_info(os)("Initialized VM with process ID %d", os::current_process_id());
666
667 // Signal Dispatcher needs to be started before VMInit event is posted
668 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
669
670 // Start Attach Listener if +StartAttachListener or it can't be started lazily
671 if (!DisableAttachMechanism) {
672 AttachListener::vm_start();
673 if (StartAttachListener || AttachListener::init_at_startup()) {
674 AttachListener::init();
675 }
676 }
677
678 // Launch -Xrun agents if EagerXrunInit is not set.
679 if (!EagerXrunInit) {
680 JvmtiAgentList::load_xrun_agents();
681 }
682
683 Arena::start_chunk_pool_cleaner_task();
684
685 // Start the service thread
686 // The service thread enqueues JVMTI deferred events and does various hashtable
687 // and other cleanups. Needs to start before the compilers start posting events.
688 ServiceThread::initialize();
689
690 // Start the monitor deflation thread:
691 MonitorDeflationThread::initialize();
692
693 // initialize compiler(s)
694 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
695 #if INCLUDE_JVMCI
696 bool force_JVMCI_intialization = false;
697 if (EnableJVMCI) {
698 // Initialize JVMCI eagerly when it is explicitly requested.
699 // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
700 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
701
702 if (!force_JVMCI_intialization) {
703 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
704 // compilations via JVMCI will not actually block until JVMCI is initialized.
705 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
706 }
707 }
708 #endif
709 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
710 // Postpone completion of compiler initialization to after JVMCI
711 // is initialized to avoid timeouts of blocking compilations.
712 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
713 CompileBroker::compilation_init_phase2();
714 }
715 #endif
716
717 // Start string deduplication thread if requested.
718 if (StringDedup::is_enabled()) {
719 StringDedup::start();
720 }
721
722 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
723 // It is done after compilers are initialized, because otherwise compilations of
724 // signature polymorphic MH intrinsics can be missed
725 // (see SystemDictionary::find_method_handle_intrinsic).
726 initialize_jsr292_core_classes(CHECK_JNI_ERR);
727
728 // This will initialize the module system. Only java.base classes can be
729 // loaded until phase 2 completes
730 call_initPhase2(CHECK_JNI_ERR);
731
732 JFR_ONLY(Jfr::on_create_vm_2();)
733
734 // Always call even when there are not JVMTI environments yet, since environments
735 // may be attached late and JVMTI must track phases of VM execution
736 JvmtiExport::enter_start_phase();
737
738 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
739 JvmtiExport::post_vm_start();
740
741 // Final system initialization including security manager and system class loader
742 call_initPhase3(CHECK_JNI_ERR);
743
744 // cache the system and platform class loaders
745 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
746
747 #if INCLUDE_CDS
748 // capture the module path info from the ModuleEntryTable
749 ClassLoader::initialize_module_path(THREAD);
750 if (HAS_PENDING_EXCEPTION) {
751 java_lang_Throwable::print(PENDING_EXCEPTION, tty);
752 vm_exit_during_initialization("ClassLoader::initialize_module_path() failed unexpectedly");
753 }
754 #endif
755
756 #if INCLUDE_JVMCI
757 if (force_JVMCI_intialization) {
758 JVMCI::initialize_compiler(CHECK_JNI_ERR);
759 CompileBroker::compilation_init_phase2();
760 }
761 #endif
762
763 if (NativeHeapTrimmer::enabled()) {
764 NativeHeapTrimmer::initialize();
765 }
766
767 // Always call even when there are not JVMTI environments yet, since environments
768 // may be attached late and JVMTI must track phases of VM execution
769 JvmtiExport::enter_live_phase();
770
771 // Make perfmemory accessible
772 PerfMemory::set_accessible(true);
773
774 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
775 JvmtiExport::post_vm_initialized();
776
777 JFR_ONLY(Jfr::on_create_vm_3();)
778
779 #if INCLUDE_MANAGEMENT
780 Management::initialize(THREAD);
781
782 if (HAS_PENDING_EXCEPTION) {
783 // management agent fails to start possibly due to
784 // configuration problem and is responsible for printing
785 // stack trace if appropriate. Simply exit VM.
786 vm_exit(1);
787 }
788 #endif // INCLUDE_MANAGEMENT
789
790 StatSampler::engage();
791 if (CheckJNICalls) JniPeriodicChecker::engage();
792
793 #if INCLUDE_RTM_OPT
794 RTMLockingCounters::init();
795 #endif
796
797 call_postVMInitHook(THREAD);
798 // The Java side of PostVMInitHook.run must deal with all
799 // exceptions and provide means of diagnosis.
800 if (HAS_PENDING_EXCEPTION) {
801 CLEAR_PENDING_EXCEPTION;
802 }
803
804 // Let WatcherThread run all registered periodic tasks now.
805 // NOTE: All PeriodicTasks should be registered by now. If they
806 // aren't, late joiners might appear to start slowly (we might
807 // take a while to process their first tick).
808 WatcherThread::run_all_tasks();
809
810 create_vm_timer.end();
811 #ifdef ASSERT
812 _vm_complete = true;
813 #endif
814
815 if (DumpSharedSpaces) {
816 MetaspaceShared::preload_and_dump();
817 }
818
819 return JNI_OK;
820 }
821
822 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
823 // the program falls off the end of main(). Another VM exit path is through
824 // vm_exit() when the program calls System.exit() to return a value or when
825 // there is a serious error in VM. The two shutdown paths are not exactly
826 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
827 // and VM_Exit op at VM level.
828 //
829 // Shutdown sequence:
830 // + Shutdown native memory tracking if it is on
831 // + Wait until we are the last non-daemon thread to execute
832 // <-- every thing is still working at this moment -->
833 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
834 // shutdown hooks
835 // + Call before_exit(), prepare for VM exit
836 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
837 // currently the only user of this mechanism is File.deleteOnExit())
838 // > stop StatSampler, watcher thread,
839 // post thread end and vm death events to JVMTI,
840 // stop signal thread
841 // + Call JavaThread::exit(), it will:
842 // > release JNI handle blocks, remove stack guard pages
843 // > remove this thread from Threads list
844 // <-- no more Java code from this thread after this point -->
845 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
846 // the compiler threads at safepoint
847 // <-- do not use anything that could get blocked by Safepoint -->
848 // + Disable tracing at JNI/JVM barriers
849 // + Set _vm_exited flag for threads that are still running native code
850 // + Call exit_globals()
851 // > deletes tty
852 // > deletes PerfMemory resources
853 // + Delete this thread
854 // + Return to caller
855
856 void Threads::destroy_vm() {
857 JavaThread* thread = JavaThread::current();
858
859 #ifdef ASSERT
860 _vm_complete = false;
861 #endif
862 // Wait until we are the last non-daemon thread to execute, or
863 // if we are a daemon then wait until the last non-daemon thread has
864 // executed.
865 bool daemon = java_lang_Thread::is_daemon(thread->threadObj());
866 int expected = daemon ? 0 : 1;
867 {
868 MonitorLocker nu(Threads_lock);
869 while (Threads::number_of_non_daemon_threads() > expected)
870 // This wait should make safepoint checks, wait without a timeout.
871 nu.wait(0);
872 }
873
874 EventShutdown e;
875 if (e.should_commit()) {
876 e.set_reason("No remaining non-daemon Java threads");
877 e.commit();
878 }
879
880 // Hang forever on exit if we are reporting an error.
881 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
882 os::infinite_sleep();
883 }
884 os::wait_for_keypress_at_exit();
885
886 // run Java level shutdown hooks
887 thread->invoke_shutdown_hooks();
888
889 before_exit(thread);
890
891 thread->exit(true);
892
893 // We are no longer on the main thread list but could still be in a
894 // secondary list where another thread may try to interact with us.
895 // So wait until all such interactions are complete before we bring
896 // the VM to the termination safepoint. Normally this would be done
897 // using thread->smr_delete() below where we delete the thread, but
898 // we can't call that after the termination safepoint is active as
899 // we will deadlock on the Threads_lock. Once all interactions are
900 // complete it is safe to directly delete the thread at any time.
901 ThreadsSMRSupport::wait_until_not_protected(thread);
902
903 // Stop VM thread.
904 {
905 // 4945125 The vm thread comes to a safepoint during exit.
906 // GC vm_operations can get caught at the safepoint, and the
907 // heap is unparseable if they are caught. Grab the Heap_lock
908 // to prevent this. The GC vm_operations will not be able to
909 // queue until after the vm thread is dead. After this point,
910 // we'll never emerge out of the safepoint before the VM exits.
911 // Assert that the thread is terminated so that acquiring the
912 // Heap_lock doesn't cause the terminated thread to participate in
913 // the safepoint protocol.
914
915 assert(thread->is_terminated(), "must be terminated here");
916 MutexLocker ml(Heap_lock);
917
918 VMThread::wait_for_vm_thread_exit();
919 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
920 VMThread::destroy();
921 }
922
923 // Now, all Java threads are gone except daemon threads. Daemon threads
924 // running Java code or in VM are stopped by the Safepoint. However,
925 // daemon threads executing native code are still running. But they
926 // will be stopped at native=>Java/VM barriers. Note that we can't
927 // simply kill or suspend them, as it is inherently deadlock-prone.
928
929 VM_Exit::set_vm_exited();
930
931 // Clean up ideal graph printers after the VMThread has started
932 // the final safepoint which will block all the Compiler threads.
933 // Note that this Thread has already logically exited so the
934 // clean_up() function's use of a JavaThreadIteratorWithHandle
935 // would be a problem except set_vm_exited() has remembered the
936 // shutdown thread which is granted a policy exception.
937 #if defined(COMPILER2) && !defined(PRODUCT)
938 IdealGraphPrinter::clean_up();
939 #endif
940
941 notify_vm_shutdown();
942
943 // exit_globals() will delete tty
944 exit_globals();
945
946 // Deleting the shutdown thread here is safe. See comment on
947 // wait_until_not_protected() above.
948 delete thread;
949
950 #if INCLUDE_JVMCI
951 if (JVMCICounterSize > 0) {
952 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
953 }
954 #endif
955
956 LogConfiguration::finalize();
957 }
958
959
960 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
961 if (version == JNI_VERSION_1_1) return JNI_TRUE;
962 return is_supported_jni_version(version);
963 }
964
965
966 jboolean Threads::is_supported_jni_version(jint version) {
967 if (version == JNI_VERSION_1_2) return JNI_TRUE;
968 if (version == JNI_VERSION_1_4) return JNI_TRUE;
969 if (version == JNI_VERSION_1_6) return JNI_TRUE;
970 if (version == JNI_VERSION_1_8) return JNI_TRUE;
971 if (version == JNI_VERSION_9) return JNI_TRUE;
972 if (version == JNI_VERSION_10) return JNI_TRUE;
973 if (version == JNI_VERSION_19) return JNI_TRUE;
974 if (version == JNI_VERSION_20) return JNI_TRUE;
975 if (version == JNI_VERSION_21) return JNI_TRUE;
976 return JNI_FALSE;
977 }
978
979 void Threads::add(JavaThread* p, bool force_daemon) {
980 // The threads lock must be owned at this point
981 assert(Threads_lock->owned_by_self(), "must have threads lock");
982
983 BarrierSet::barrier_set()->on_thread_attach(p);
984
985 // Once a JavaThread is added to the Threads list, smr_delete() has
986 // to be used to delete it. Otherwise we can just delete it directly.
987 p->set_on_thread_list();
988
989 _number_of_threads++;
990 oop threadObj = p->threadObj();
991 bool daemon = true;
992 // Bootstrapping problem: threadObj can be null for initial
993 // JavaThread (or for threads attached via JNI)
994 if (!force_daemon &&
995 (threadObj == nullptr || !java_lang_Thread::is_daemon(threadObj))) {
996 _number_of_non_daemon_threads++;
997 daemon = false;
998 }
999
1000 ThreadService::add_thread(p, daemon);
1001
1002 // Maintain fast thread list
1003 ThreadsSMRSupport::add_thread(p);
1004
1005 // Increase the ObjectMonitor ceiling for the new thread.
1006 ObjectSynchronizer::inc_in_use_list_ceiling();
1007
1008 // Possible GC point.
1009 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
1010
1011 // Make new thread known to active EscapeBarrier
1012 EscapeBarrier::thread_added(p);
1013 }
1014
1015 void Threads::remove(JavaThread* p, bool is_daemon) {
1016 // Extra scope needed for Thread_lock, so we can check
1017 // that we do not remove thread without safepoint code notice
1018 { MonitorLocker ml(Threads_lock);
1019
1020 if (ThreadIdTable::is_initialized()) {
1021 // This cleanup must be done before the current thread's GC barrier
1022 // is detached since we need to touch the threadObj oop.
1023 jlong tid = SharedRuntime::get_java_tid(p);
1024 ThreadIdTable::remove_thread(tid);
1025 }
1026
1027 // BarrierSet state must be destroyed after the last thread transition
1028 // before the thread terminates. Thread transitions result in calls to
1029 // StackWatermarkSet::on_safepoint(), which performs GC processing,
1030 // requiring the GC state to be alive.
1031 BarrierSet::barrier_set()->on_thread_detach(p);
1032 if (p->is_exiting()) {
1033 // If we got here via JavaThread::exit(), then we remember that the
1034 // thread's GC barrier has been detached. We don't do this when we get
1035 // here from another path, e.g., cleanup_failed_attach_current_thread().
1036 p->set_terminated(JavaThread::_thread_gc_barrier_detached);
1037 }
1038
1039 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
1040
1041 // Maintain fast thread list
1042 ThreadsSMRSupport::remove_thread(p);
1043
1044 _number_of_threads--;
1045 if (!is_daemon) {
1046 _number_of_non_daemon_threads--;
1047
1048 // If this is the last non-daemon thread then we need to do
1049 // a notify on the Threads_lock so a thread waiting
1050 // on destroy_vm will wake up. But that thread could be a daemon
1051 // or non-daemon, so we notify for both the 0 and 1 case.
1052 if (number_of_non_daemon_threads() <= 1) {
1053 ml.notify_all();
1054 }
1055 }
1056 ThreadService::remove_thread(p, is_daemon);
1057
1058 // Make sure that safepoint code disregard this thread. This is needed since
1059 // the thread might mess around with locks after this point. This can cause it
1060 // to do callbacks into the safepoint code. However, the safepoint code is not aware
1061 // of this thread since it is removed from the queue.
1062 p->set_terminated(JavaThread::_thread_terminated);
1063
1064 // Notify threads waiting in EscapeBarriers
1065 EscapeBarrier::thread_removed(p);
1066 } // unlock Threads_lock
1067
1068 // Reduce the ObjectMonitor ceiling for the exiting thread.
1069 ObjectSynchronizer::dec_in_use_list_ceiling();
1070
1071 // Since Events::log uses a lock, we grab it outside the Threads_lock
1072 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
1073 }
1074
1075 // Operations on the Threads list for GC. These are not explicitly locked,
1076 // but the garbage collector must provide a safe context for them to run.
1077 // In particular, these things should never be called when the Threads_lock
1078 // is held by some other thread. (Note: the Safepoint abstraction also
1079 // uses the Threads_lock to guarantee this property. It also makes sure that
1080 // all threads gets blocked when exiting or starting).
1081
1082 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
1083 ALL_JAVA_THREADS(p) {
1084 p->oops_do(f, cf);
1085 }
1086 VMThread::vm_thread()->oops_do(f, cf);
1087 }
1088
1089 void Threads::change_thread_claim_token() {
1090 if (++_thread_claim_token == 0) {
1091 // On overflow of the token counter, there is a risk of future
1092 // collisions between a new global token value and a stale token
1093 // for a thread, because not all iterations visit all threads.
1094 // (Though it's pretty much a theoretical concern for non-trivial
1095 // token counter sizes.) To deal with the possibility, reset all
1096 // the thread tokens to zero on global token overflow.
1097 struct ResetClaims : public ThreadClosure {
1098 virtual void do_thread(Thread* t) {
1099 t->claim_threads_do(false, 0);
1100 }
1101 } reset_claims;
1102 Threads::threads_do(&reset_claims);
1103 // On overflow, update the global token to non-zero, to
1104 // avoid the special "never claimed" initial thread value.
1105 _thread_claim_token = 1;
1106 }
1107 }
1108
1109 #ifdef ASSERT
1110 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
1111 const uintx token = t->threads_do_token();
1112 assert(token == expected,
1113 "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
1114 UINTX_FORMAT, kind, p2i(t), token, expected);
1115 }
1116
1117 void Threads::assert_all_threads_claimed() {
1118 ALL_JAVA_THREADS(p) {
1119 assert_thread_claimed("JavaThread", p, _thread_claim_token);
1120 }
1121
1122 struct NJTClaimedVerifierClosure : public ThreadClosure {
1123 uintx _thread_claim_token;
1124
1125 NJTClaimedVerifierClosure(uintx thread_claim_token) : ThreadClosure(), _thread_claim_token(thread_claim_token) { }
1126
1127 virtual void do_thread(Thread* thread) override {
1128 assert_thread_claimed("Non-JavaThread", VMThread::vm_thread(), _thread_claim_token);
1129 }
1130 } tc(_thread_claim_token);
1131
1132 non_java_threads_do(&tc);
1133 }
1134 #endif // ASSERT
1135
1136 class ParallelOopsDoThreadClosure : public ThreadClosure {
1137 private:
1138 OopClosure* _f;
1139 CodeBlobClosure* _cf;
1140 public:
1141 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
1142 void do_thread(Thread* t) {
1143 t->oops_do(_f, _cf);
1144 }
1145 };
1146
1147 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
1148 ParallelOopsDoThreadClosure tc(f, cf);
1149 possibly_parallel_threads_do(is_par, &tc);
1150 }
1151
1152 void Threads::metadata_do(MetadataClosure* f) {
1153 ALL_JAVA_THREADS(p) {
1154 p->metadata_do(f);
1155 }
1156 }
1157
1158 class ThreadHandlesClosure : public ThreadClosure {
1159 void (*_f)(Metadata*);
1160 public:
1161 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
1162 virtual void do_thread(Thread* thread) {
1163 thread->metadata_handles_do(_f);
1164 }
1165 };
1166
1167 void Threads::metadata_handles_do(void f(Metadata*)) {
1168 // Only walk the Handles in Thread.
1169 ThreadHandlesClosure handles_closure(f);
1170 threads_do(&handles_closure);
1171 }
1172
1173 // Get count Java threads that are waiting to enter the specified monitor.
1174 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
1175 int count,
1176 address monitor) {
1177 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
1178
1179 int i = 0;
1180 for (JavaThread* p : *t_list) {
1181 if (!p->can_call_java()) continue;
1182
1183 // The first stage of async deflation does not affect any field
1184 // used by this comparison so the ObjectMonitor* is usable here.
1185 address pending = (address)p->current_pending_monitor();
1186 if (pending == monitor) { // found a match
1187 if (i < count) result->append(p); // save the first count matches
1188 i++;
1189 }
1190 }
1191
1192 return result;
1193 }
1194
1195
1196 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
1197 address owner) {
1198 assert(LockingMode != LM_LIGHTWEIGHT, "Not with new lightweight locking");
1199 // null owner means not locked so we can skip the search
1200 if (owner == nullptr) return nullptr;
1201
1202 for (JavaThread* p : *t_list) {
1203 // first, see if owner is the address of a Java thread
1204 if (owner == (address)p) return p;
1205 }
1206
1207 // Cannot assert on lack of success here since this function may be
1208 // used by code that is trying to report useful problem information
1209 // like deadlock detection.
1210 if (LockingMode == LM_MONITOR) return nullptr;
1211
1212 // If we didn't find a matching Java thread and we didn't force use of
1213 // heavyweight monitors, then the owner is the stack address of the
1214 // Lock Word in the owning Java thread's stack.
1215 //
1216 JavaThread* the_owner = nullptr;
1217 for (JavaThread* q : *t_list) {
1218 if (q->is_lock_owned(owner)) {
1219 the_owner = q;
1220 break;
1221 }
1222 }
1223
1224 // cannot assert on lack of success here; see above comment
1225 return the_owner;
1226 }
1227
1228 JavaThread* Threads::owning_thread_from_object(ThreadsList * t_list, oop obj) {
1229 assert(LockingMode == LM_LIGHTWEIGHT, "Only with new lightweight locking");
1230 for (JavaThread* q : *t_list) {
1231 if (q->lock_stack().contains(obj)) {
1232 return q;
1233 }
1234 }
1235 return nullptr;
1236 }
1237
1238 JavaThread* Threads::owning_thread_from_monitor(ThreadsList* t_list, ObjectMonitor* monitor) {
1239 if (LockingMode == LM_LIGHTWEIGHT) {
1240 if (monitor->is_owner_anonymous()) {
1241 return owning_thread_from_object(t_list, monitor->object());
1242 } else {
1243 Thread* owner = reinterpret_cast<Thread*>(monitor->owner());
1244 assert(owner == nullptr || owner->is_Java_thread(), "only JavaThreads own monitors");
1245 return reinterpret_cast<JavaThread*>(owner);
1246 }
1247 } else {
1248 address owner = (address)monitor->owner();
1249 return owning_thread_from_monitor_owner(t_list, owner);
1250 }
1251 }
1252
1253 class PrintOnClosure : public ThreadClosure {
1254 private:
1255 outputStream* _st;
1256
1257 public:
1258 PrintOnClosure(outputStream* st) :
1259 _st(st) {}
1260
1261 virtual void do_thread(Thread* thread) {
1262 if (thread != nullptr) {
1263 thread->print_on(_st);
1264 _st->cr();
1265 }
1266 }
1267 };
1268
1269 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
1270 void Threads::print_on(outputStream* st, bool print_stacks,
1271 bool internal_format, bool print_concurrent_locks,
1272 bool print_extended_info) {
1273 char buf[32];
1274 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
1275
1276 st->print_cr("Full thread dump %s (%s %s):",
1277 VM_Version::vm_name(),
1278 VM_Version::vm_release(),
1279 VM_Version::vm_info_string());
1280 st->cr();
1281
1282 #if INCLUDE_SERVICES
1283 // Dump concurrent locks
1284 ConcurrentLocksDump concurrent_locks;
1285 if (print_concurrent_locks) {
1286 concurrent_locks.dump_at_safepoint();
1287 }
1288 #endif // INCLUDE_SERVICES
1289
1290 ThreadsSMRSupport::print_info_on(st);
1291 st->cr();
1292
1293 ALL_JAVA_THREADS(p) {
1294 ResourceMark rm;
1295 p->print_on(st, print_extended_info);
1296 if (print_stacks) {
1297 if (internal_format) {
1298 p->trace_stack();
1299 } else {
1300 p->print_stack_on(st);
1301 }
1302 }
1303 st->cr();
1304 #if INCLUDE_SERVICES
1305 if (print_concurrent_locks) {
1306 concurrent_locks.print_locks_on(p, st);
1307 }
1308 #endif // INCLUDE_SERVICES
1309 }
1310
1311 PrintOnClosure cl(st);
1312 cl.do_thread(VMThread::vm_thread());
1313 Universe::heap()->gc_threads_do(&cl);
1314 cl.do_thread(WatcherThread::watcher_thread());
1315 cl.do_thread(AsyncLogWriter::instance());
1316
1317 st->flush();
1318 }
1319
1320 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
1321 int buflen, bool* found_current) {
1322 if (this_thread != nullptr) {
1323 bool is_current = (current == this_thread);
1324 *found_current = *found_current || is_current;
1325 st->print("%s", is_current ? "=>" : " ");
1326
1327 st->print(PTR_FORMAT, p2i(this_thread));
1328 st->print(" ");
1329 this_thread->print_on_error(st, buf, buflen);
1330 st->cr();
1331 }
1332 }
1333
1334 class PrintOnErrorClosure : public ThreadClosure {
1335 outputStream* _st;
1336 Thread* _current;
1337 char* _buf;
1338 int _buflen;
1339 bool* _found_current;
1340 unsigned _num_printed;
1341 public:
1342 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
1343 int buflen, bool* found_current) :
1344 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current),
1345 _num_printed(0) {}
1346
1347 virtual void do_thread(Thread* thread) {
1348 _num_printed++;
1349 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
1350 }
1351
1352 unsigned num_printed() const { return _num_printed; }
1353 };
1354
1355 // Threads::print_on_error() is called by fatal error handler. It's possible
1356 // that VM is not at safepoint and/or current thread is inside signal handler.
1357 // Don't print stack trace, as the stack may not be walkable. Don't allocate
1358 // memory (even in resource area), it might deadlock the error handler.
1359 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
1360 int buflen) {
1361 ThreadsSMRSupport::print_info_on(st);
1362 st->cr();
1363
1364 bool found_current = false;
1365 st->print_cr("Java Threads: ( => current thread )");
1366 unsigned num_java = 0;
1367 ALL_JAVA_THREADS(thread) {
1368 print_on_error(thread, st, current, buf, buflen, &found_current);
1369 num_java++;
1370 }
1371 st->print_cr("Total: %u", num_java);
1372 st->cr();
1373
1374 st->print_cr("Other Threads:");
1375 unsigned num_other = ((VMThread::vm_thread() != nullptr) ? 1 : 0) +
1376 ((WatcherThread::watcher_thread() != nullptr) ? 1 : 0) +
1377 ((AsyncLogWriter::instance() != nullptr) ? 1 : 0);
1378 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
1379 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
1380 print_on_error(AsyncLogWriter::instance(), st, current, buf, buflen, &found_current);
1381
1382 if (Universe::heap() != nullptr) {
1383 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
1384 Universe::heap()->gc_threads_do(&print_closure);
1385 num_other += print_closure.num_printed();
1386 }
1387
1388 if (!found_current) {
1389 st->cr();
1390 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
1391 current->print_on_error(st, buf, buflen);
1392 num_other++;
1393 st->cr();
1394 }
1395 st->print_cr("Total: %u", num_other);
1396 st->cr();
1397
1398 st->print_cr("Threads with active compile tasks:");
1399 unsigned num = print_threads_compiling(st, buf, buflen);
1400 st->print_cr("Total: %u", num);
1401 }
1402
1403 unsigned Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
1404 unsigned num = 0;
1405 ALL_JAVA_THREADS(thread) {
1406 if (thread->is_Compiler_thread()) {
1407 CompilerThread* ct = (CompilerThread*) thread;
1408
1409 // Keep task in local variable for null check.
1410 // ct->_task might be set to null by concurring compiler thread
1411 // because it completed the compilation. The task is never freed,
1412 // though, just returned to a free list.
1413 CompileTask* task = ct->task();
1414 if (task != nullptr) {
1415 thread->print_name_on_error(st, buf, buflen);
1416 st->print(" ");
1417 task->print(st, nullptr, short_form, true);
1418 num++;
1419 }
1420 }
1421 }
1422 return num;
1423 }
1424
1425 void Threads::verify() {
1426 ALL_JAVA_THREADS(p) {
1427 p->verify();
1428 }
1429 VMThread* thread = VMThread::vm_thread();
1430 if (thread != nullptr) thread->verify();
1431 }