1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/symbolTable.hpp"
27 #include "classfile/vmSymbols.hpp"
28 #include "code/codeCache.hpp"
29 #include "compiler/compileBroker.hpp"
30 #include "gc/shared/isGCActiveMark.hpp"
31 #include "logging/log.hpp"
32 #include "logging/logStream.hpp"
33 #include "memory/heapInspection.hpp"
34 #include "memory/resourceArea.hpp"
35 #include "oops/symbol.hpp"
36 #include "runtime/arguments.hpp"
37 #include "runtime/deoptimization.hpp"
38 #include "runtime/frame.inline.hpp"
39 #include "runtime/interfaceSupport.inline.hpp"
40 #include "runtime/sweeper.hpp"
41 #include "runtime/thread.inline.hpp"
42 #include "runtime/threadSMR.inline.hpp"
43 #include "runtime/vm_operations.hpp"
44 #include "services/threadService.hpp"
45
46 #define VM_OP_NAME_INITIALIZE(name) #name,
47
48 const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \
49 { VM_OPS_DO(VM_OP_NAME_INITIALIZE) };
50
51 void VM_Operation::set_calling_thread(Thread* thread, ThreadPriority priority) {
52 _calling_thread = thread;
53 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
54 _priority = priority;
55 }
56
57
58 void VM_Operation::evaluate() {
59 ResourceMark rm;
60 LogTarget(Debug, vmoperation) lt;
61 if (lt.is_enabled()) {
62 LogStream ls(lt);
63 ls.print("begin ");
64 print_on_error(&ls);
65 ls.cr();
66 }
67 doit();
68 if (lt.is_enabled()) {
69 LogStream ls(lt);
70 ls.print("end ");
71 print_on_error(&ls);
72 ls.cr();
73 }
74 }
75
76 const char* VM_Operation::mode_to_string(Mode mode) {
77 switch(mode) {
78 case _safepoint : return "safepoint";
79 case _no_safepoint : return "no safepoint";
80 case _concurrent : return "concurrent";
81 case _async_safepoint: return "async safepoint";
82 default : return "unknown";
83 }
84 }
85 // Called by fatal error handler.
86 void VM_Operation::print_on_error(outputStream* st) const {
87 st->print("VM_Operation (" PTR_FORMAT "): ", p2i(this));
88 st->print("%s", name());
89
90 const char* mode = mode_to_string(evaluation_mode());
91 st->print(", mode: %s", mode);
92
93 if (calling_thread()) {
94 st->print(", requested by thread " PTR_FORMAT, p2i(calling_thread()));
95 }
96 }
97
98 void VM_ThreadStop::doit() {
99 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
100 ThreadsListHandle tlh;
101 JavaThread* target = java_lang_Thread::thread(target_thread());
102 // Note that this now allows multiple ThreadDeath exceptions to be
103 // thrown at a thread.
104 if (target != NULL && (!EnableThreadSMRExtraValidityChecks || tlh.includes(target))) {
105 // The target thread has run and has not exited yet.
106 target->send_thread_stop(throwable());
107 }
108 }
109
110 void VM_ClearICs::doit() {
111 if (_preserve_static_stubs) {
112 CodeCache::cleanup_inline_caches();
113 } else {
114 CodeCache::clear_inline_caches();
115 }
116 }
117
118 void VM_Deoptimize::doit() {
119 // We do not want any GCs to happen while we are in the middle of this VM operation
120 ResourceMark rm;
121 DeoptimizationMarker dm;
122
123 // Deoptimize all activations depending on marked nmethods
124 Deoptimization::deoptimize_dependents();
125
126 // Make the dependent methods not entrant
127 CodeCache::make_marked_nmethods_not_entrant();
128 }
129
130 void VM_MarkActiveNMethods::doit() {
131 NMethodSweeper::mark_active_nmethods();
132 }
133
134 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id, int reason) {
135 _thread = thread;
136 _id = id;
137 _reason = reason;
138 }
139
140
141 void VM_DeoptimizeFrame::doit() {
142 assert(_reason > Deoptimization::Reason_none && _reason < Deoptimization::Reason_LIMIT, "invalid deopt reason");
143 Deoptimization::deoptimize_frame_internal(_thread, _id, (Deoptimization::DeoptReason)_reason);
144 }
145
146
147 #ifndef PRODUCT
148
149 void VM_DeoptimizeAll::doit() {
150 DeoptimizationMarker dm;
151 JavaThreadIteratorWithHandle jtiwh;
152 // deoptimize all java threads in the system
153 if (DeoptimizeALot) {
154 for (; JavaThread *thread = jtiwh.next(); ) {
155 if (thread->has_last_Java_frame()) {
156 thread->deoptimize();
157 }
158 }
159 } else if (DeoptimizeRandom) {
160
161 // Deoptimize some selected threads and frames
162 int tnum = os::random() & 0x3;
163 int fnum = os::random() & 0x3;
164 int tcount = 0;
165 for (; JavaThread *thread = jtiwh.next(); ) {
166 if (thread->has_last_Java_frame()) {
167 if (tcount++ == tnum) {
168 tcount = 0;
169 int fcount = 0;
170 // Deoptimize some selected frames.
171 // Biased llocking wants a updated register map
172 for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) {
173 if (fst.current()->can_be_deoptimized()) {
174 if (fcount++ == fnum) {
175 fcount = 0;
176 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map());
177 }
178 }
179 }
180 }
181 }
182 }
183 }
184 }
185
186
187 void VM_ZombieAll::doit() {
188 JavaThread *thread = (JavaThread *)calling_thread();
189 assert(thread->is_Java_thread(), "must be a Java thread");
190 thread->make_zombies();
191 }
192
193 #endif // !PRODUCT
194
195 void VM_UnlinkSymbols::doit() {
196 JavaThread *thread = (JavaThread *)calling_thread();
197 assert(thread->is_Java_thread(), "must be a Java thread");
198 SymbolTable::unlink();
199 }
200
201 void VM_Verify::doit() {
202 Universe::heap()->prepare_for_verify();
203 Universe::verify();
204 }
205
206 bool VM_PrintThreads::doit_prologue() {
207 // Get Heap_lock if concurrent locks will be dumped
208 if (_print_concurrent_locks) {
209 Heap_lock->lock();
210 }
211 return true;
212 }
213
214 void VM_PrintThreads::doit() {
215 Threads::print_on(_out, true, false, _print_concurrent_locks, _extended_thread_info);
216 }
217
218 void VM_PrintThreads::doit_epilogue() {
219 if (_print_concurrent_locks) {
220 // Release Heap_lock
221 Heap_lock->unlock();
222 }
223 }
224
225 void VM_PrintJNI::doit() {
226 JNIHandles::print_on(_out);
227 }
228
229 void VM_PrintMetadata::doit() {
230 MetaspaceUtils::print_report(_out, _scale, _flags);
231 }
232
233 VM_FindDeadlocks::~VM_FindDeadlocks() {
234 if (_deadlocks != NULL) {
235 DeadlockCycle* cycle = _deadlocks;
236 while (cycle != NULL) {
237 DeadlockCycle* d = cycle;
238 cycle = cycle->next();
239 delete d;
240 }
241 }
242 }
243
244 void VM_FindDeadlocks::doit() {
245 // Update the hazard ptr in the originating thread to the current
246 // list of threads. This VM operation needs the current list of
247 // threads for proper deadlock detection and those are the
248 // JavaThreads we need to be protected when we return info to the
249 // originating thread.
250 _setter.set();
251
252 _deadlocks = ThreadService::find_deadlocks_at_safepoint(_setter.list(), _concurrent_locks);
253 if (_out != NULL) {
254 int num_deadlocks = 0;
255 for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) {
256 num_deadlocks++;
257 cycle->print_on_with(_setter.list(), _out);
258 }
259
260 if (num_deadlocks == 1) {
261 _out->print_cr("\nFound 1 deadlock.\n");
262 _out->flush();
263 } else if (num_deadlocks > 1) {
264 _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);
265 _out->flush();
266 }
267 }
268 }
269
270 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
271 int max_depth,
272 bool with_locked_monitors,
273 bool with_locked_synchronizers) {
274 _result = result;
275 _num_threads = 0; // 0 indicates all threads
276 _threads = NULL;
277 _result = result;
278 _max_depth = max_depth;
279 _with_locked_monitors = with_locked_monitors;
280 _with_locked_synchronizers = with_locked_synchronizers;
281 }
282
283 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
284 GrowableArray<instanceHandle>* threads,
285 int num_threads,
286 int max_depth,
287 bool with_locked_monitors,
288 bool with_locked_synchronizers) {
289 _result = result;
290 _num_threads = num_threads;
291 _threads = threads;
292 _result = result;
293 _max_depth = max_depth;
294 _with_locked_monitors = with_locked_monitors;
295 _with_locked_synchronizers = with_locked_synchronizers;
296 }
297
298 bool VM_ThreadDump::doit_prologue() {
299 if (_with_locked_synchronizers) {
300 // Acquire Heap_lock to dump concurrent locks
301 Heap_lock->lock();
302 }
303
304 return true;
305 }
306
307 void VM_ThreadDump::doit_epilogue() {
308 if (_with_locked_synchronizers) {
309 // Release Heap_lock
310 Heap_lock->unlock();
311 }
312 }
313
314 void VM_ThreadDump::doit() {
315 ResourceMark rm;
316
317 // Set the hazard ptr in the originating thread to protect the
318 // current list of threads. This VM operation needs the current list
319 // of threads for a proper dump and those are the JavaThreads we need
320 // to be protected when we return info to the originating thread.
321 _result->set_t_list();
322
323 ConcurrentLocksDump concurrent_locks(true);
324 if (_with_locked_synchronizers) {
325 concurrent_locks.dump_at_safepoint();
326 }
327
328 if (_num_threads == 0) {
329 // Snapshot all live threads
330
331 for (uint i = 0; i < _result->t_list()->length(); i++) {
332 JavaThread* jt = _result->t_list()->thread_at(i);
333 if (jt->is_exiting() ||
334 jt->is_hidden_from_external_view()) {
335 // skip terminating threads and hidden threads
336 continue;
337 }
338 ThreadConcurrentLocks* tcl = NULL;
339 if (_with_locked_synchronizers) {
340 tcl = concurrent_locks.thread_concurrent_locks(jt);
341 }
342 ThreadSnapshot* ts = snapshot_thread(jt, tcl);
343 _result->add_thread_snapshot(ts);
344 }
345 } else {
346 // Snapshot threads in the given _threads array
347 // A dummy snapshot is created if a thread doesn't exist
348
349 for (int i = 0; i < _num_threads; i++) {
350 instanceHandle th = _threads->at(i);
351 if (th() == NULL) {
352 // skip if the thread doesn't exist
353 // Add a dummy snapshot
354 _result->add_thread_snapshot(new ThreadSnapshot());
355 continue;
356 }
357
358 // Dump thread stack only if the thread is alive and not exiting
359 // and not VM internal thread.
360 JavaThread* jt = java_lang_Thread::thread(th());
361 if (jt != NULL && !_result->t_list()->includes(jt)) {
362 // _threads[i] doesn't refer to a valid JavaThread; this check
363 // is primarily for JVM_DumpThreads() which doesn't have a good
364 // way to validate the _threads array.
365 jt = NULL;
366 }
367 if (jt == NULL || /* thread not alive */
368 jt->is_exiting() ||
369 jt->is_hidden_from_external_view()) {
370 // add a NULL snapshot if skipped
371 _result->add_thread_snapshot(new ThreadSnapshot());
372 continue;
373 }
374 ThreadConcurrentLocks* tcl = NULL;
375 if (_with_locked_synchronizers) {
376 tcl = concurrent_locks.thread_concurrent_locks(jt);
377 }
378 ThreadSnapshot* ts = snapshot_thread(jt, tcl);
379 _result->add_thread_snapshot(ts);
380 }
381 }
382 }
383
384 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) {
385 ThreadSnapshot* snapshot = new ThreadSnapshot(_result->t_list(), java_thread);
386 snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors);
387 snapshot->set_concurrent_locks(tcl);
388 return snapshot;
389 }
390
391 volatile bool VM_Exit::_vm_exited = false;
392 Thread * volatile VM_Exit::_shutdown_thread = NULL;
393
394 int VM_Exit::set_vm_exited() {
395
396 Thread * thr_cur = Thread::current();
397
398 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
399
400 int num_active = 0;
401
402 _shutdown_thread = thr_cur;
403 _vm_exited = true; // global flag
404 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thr = jtiwh.next(); ) {
405 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
406 ++num_active;
407 thr->set_terminated(JavaThread::_vm_exited); // per-thread flag
408 }
409 }
410
411 return num_active;
412 }
413
414 int VM_Exit::wait_for_threads_in_native_to_block() {
415 // VM exits at safepoint. This function must be called at the final safepoint
416 // to wait for threads in _thread_in_native state to be quiescent.
417 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
418
419 Thread * thr_cur = Thread::current();
420 Monitor timer(Mutex::leaf, "VM_Exit timer", true,
421 Monitor::_safepoint_check_never);
422
423 // Compiler threads need longer wait because they can access VM data directly
424 // while in native. If they are active and some structures being used are
425 // deleted by the shutdown sequence, they will crash. On the other hand, user
426 // threads must go through native=>Java/VM transitions first to access VM
427 // data, and they will be stopped during state transition. In theory, we
428 // don't have to wait for user threads to be quiescent, but it's always
429 // better to terminate VM when current thread is the only active thread, so
430 // wait for user threads too. Numbers are in 10 milliseconds.
431 int max_wait_user_thread = 30; // at least 300 milliseconds
432 int max_wait_compiler_thread = 1000; // at least 10 seconds
433
434 int max_wait = max_wait_compiler_thread;
435
436 int attempts = 0;
437 JavaThreadIteratorWithHandle jtiwh;
438 while (true) {
439 int num_active = 0;
440 int num_active_compiler_thread = 0;
441
442 jtiwh.rewind();
443 for (; JavaThread *thr = jtiwh.next(); ) {
444 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
445 num_active++;
446 if (thr->is_Compiler_thread()) {
447 num_active_compiler_thread++;
448 }
449 }
450 }
451
452 if (num_active == 0) {
453 return 0;
454 } else if (attempts > max_wait) {
455 return num_active;
456 } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
457 return num_active;
458 }
459
460 attempts++;
461
462 MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag);
463 timer.wait(Mutex::_no_safepoint_check_flag, 10);
464 }
465 }
466
467 void VM_Exit::doit() {
468 CompileBroker::set_should_block();
469
470 // Wait for a short period for threads in native to block. Any thread
471 // still executing native code after the wait will be stopped at
472 // native==>Java/VM barriers.
473 // Among 16276 JCK tests, 94% of them come here without any threads still
474 // running in native; the other 6% are quiescent within 250ms (Ultra 80).
475 wait_for_threads_in_native_to_block();
476
477 set_vm_exited();
478
479 // cleanup globals resources before exiting. exit_globals() currently
480 // cleans up outputStream resources and PerfMemory resources.
481 exit_globals();
482
483 // Check for exit hook
484 exit_hook_t exit_hook = Arguments::exit_hook();
485 if (exit_hook != NULL) {
486 // exit hook should exit.
487 exit_hook(_exit_code);
488 // ... but if it didn't, we must do it here
489 vm_direct_exit(_exit_code);
490 } else {
491 vm_direct_exit(_exit_code);
492 }
493 }
494
495
496 void VM_Exit::wait_if_vm_exited() {
497 if (_vm_exited &&
498 Thread::current_or_null() != _shutdown_thread) {
499 // _vm_exited is set at safepoint, and the Threads_lock is never released
500 // we will block here until the process dies
501 Threads_lock->lock_without_safepoint_check();
502 ShouldNotReachHere();
503 }
504 }
505
506 void VM_PrintCompileQueue::doit() {
507 CompileBroker::print_compile_queues(_out);
508 }
509
510 #if INCLUDE_SERVICES
511 void VM_PrintClassHierarchy::doit() {
512 KlassHierarchy::print_class_hierarchy(_out, _print_interfaces, _print_subclasses, _classname);
513 }
514 #endif