1 /*
2 * Copyright (c) 1997, 2016, 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 "code/codeCacheExtensions.hpp"
30 #include "compiler/compileBroker.hpp"
31 #include "gc/shared/isGCActiveMark.hpp"
32 #include "logging/log.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/interfaceSupport.hpp"
39 #include "runtime/sweeper.hpp"
40 #include "runtime/thread.inline.hpp"
41 #include "runtime/vm_operations.hpp"
42 #include "services/threadService.hpp"
43 #include "trace/tracing.hpp"
44
45 #define VM_OP_NAME_INITIALIZE(name) #name,
46
47 const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \
48 { VM_OPS_DO(VM_OP_NAME_INITIALIZE) };
49
50 void VM_Operation::set_calling_thread(Thread* thread, ThreadPriority priority) {
51 _calling_thread = thread;
52 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
53 _priority = priority;
54 }
55
56
57 void VM_Operation::evaluate() {
58 ResourceMark rm;
59 outputStream* debugstream;
60 bool enabled = log_is_enabled(Debug, vmoperation);
61 if (enabled) {
62 debugstream = Log(vmoperation)::debug_stream();
63 debugstream->print("begin ");
64 print_on_error(debugstream);
65 debugstream->cr();
66 }
67 doit();
68 if (enabled) {
69 debugstream->print("end ");
70 print_on_error(debugstream);
71 debugstream->cr();
72 }
73 }
74
75 const char* VM_Operation::mode_to_string(Mode mode) {
76 switch(mode) {
77 case _safepoint : return "safepoint";
78 case _no_safepoint : return "no safepoint";
79 case _concurrent : return "concurrent";
80 case _async_safepoint: return "async safepoint";
81 default : return "unknown";
82 }
83 }
84 // Called by fatal error handler.
85 void VM_Operation::print_on_error(outputStream* st) const {
86 st->print("VM_Operation (" PTR_FORMAT "): ", p2i(this));
87 st->print("%s", name());
88
89 const char* mode = mode_to_string(evaluation_mode());
90 st->print(", mode: %s", mode);
91
92 if (calling_thread()) {
93 st->print(", requested by thread " PTR_FORMAT, p2i(calling_thread()));
94 }
95 }
96
97 void VM_ThreadStop::doit() {
98 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
99 JavaThread* target = java_lang_Thread::thread(target_thread());
100 // Note that this now allows multiple ThreadDeath exceptions to be
101 // thrown at a thread.
102 if (target != NULL) {
103 // the thread has run and is not already in the process of exiting
104 target->send_thread_stop(throwable());
105 }
106 }
107
108 void VM_ClearICs::doit() {
109 if (_preserve_static_stubs) {
110 CodeCache::cleanup_inline_caches();
111 } else {
112 CodeCache::clear_inline_caches();
113 }
114 }
115
116 void VM_Deoptimize::doit() {
117 // We do not want any GCs to happen while we are in the middle of this VM operation
118 ResourceMark rm;
119 DeoptimizationMarker dm;
120
121 // Deoptimize all activations depending on marked nmethods
122 Deoptimization::deoptimize_dependents();
123
124 // Make the dependent methods not entrant
125 CodeCache::make_marked_nmethods_not_entrant();
126 }
127
128 void VM_MarkActiveNMethods::doit() {
129 NMethodSweeper::mark_active_nmethods();
130 }
131
132 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id, int reason) {
133 _thread = thread;
134 _id = id;
135 _reason = reason;
136 }
137
138
139 void VM_DeoptimizeFrame::doit() {
140 assert(_reason > Deoptimization::Reason_none && _reason < Deoptimization::Reason_LIMIT, "invalid deopt reason");
141 Deoptimization::deoptimize_frame_internal(_thread, _id, (Deoptimization::DeoptReason)_reason);
142 }
143
144
145 #ifndef PRODUCT
146
147 void VM_DeoptimizeAll::doit() {
148 DeoptimizationMarker dm;
149 // deoptimize all java threads in the system
150 if (DeoptimizeALot) {
151 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
152 if (thread->has_last_Java_frame()) {
153 thread->deoptimize();
154 }
155 }
156 } else if (DeoptimizeRandom) {
157
158 // Deoptimize some selected threads and frames
159 int tnum = os::random() & 0x3;
160 int fnum = os::random() & 0x3;
161 int tcount = 0;
162 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
163 if (thread->has_last_Java_frame()) {
164 if (tcount++ == tnum) {
165 tcount = 0;
166 int fcount = 0;
167 // Deoptimize some selected frames.
168 // Biased llocking wants a updated register map
169 for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) {
170 if (fst.current()->can_be_deoptimized()) {
171 if (fcount++ == fnum) {
172 fcount = 0;
173 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map());
174 }
175 }
176 }
177 }
178 }
179 }
180 }
181 }
182
183
184 void VM_ZombieAll::doit() {
185 JavaThread *thread = (JavaThread *)calling_thread();
186 assert(thread->is_Java_thread(), "must be a Java thread");
187 thread->make_zombies();
188 }
189
190 #endif // !PRODUCT
191
192 void VM_UnlinkSymbols::doit() {
193 JavaThread *thread = (JavaThread *)calling_thread();
194 assert(thread->is_Java_thread(), "must be a Java thread");
195 SymbolTable::unlink();
196 }
197
198 void VM_Verify::doit() {
199 Universe::heap()->prepare_for_verify();
200 Universe::verify();
201 }
202
203 bool VM_PrintThreads::doit_prologue() {
204 // Make sure AbstractOwnableSynchronizer is loaded
205 JavaThread* jt = JavaThread::current();
206 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt);
207 if (jt->has_pending_exception()) {
208 return false;
209 }
210
211 // Get Heap_lock if concurrent locks will be dumped
212 if (_print_concurrent_locks) {
213 Heap_lock->lock();
214 }
215 return true;
216 }
217
218 void VM_PrintThreads::doit() {
219 Threads::print_on(_out, true, false, _print_concurrent_locks);
220 }
221
222 void VM_PrintThreads::doit_epilogue() {
223 if (_print_concurrent_locks) {
224 // Release Heap_lock
225 Heap_lock->unlock();
226 }
227 }
228
229 void VM_PrintJNI::doit() {
230 JNIHandles::print_on(_out);
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 bool VM_FindDeadlocks::doit_prologue() {
245 if (_concurrent_locks) {
246 // Make sure AbstractOwnableSynchronizer is loaded
247 JavaThread* jt = JavaThread::current();
248 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt);
249 if (jt->has_pending_exception()) {
250 return false;
251 }
252 }
253
254 return true;
255 }
256
257 void VM_FindDeadlocks::doit() {
258 _deadlocks = ThreadService::find_deadlocks_at_safepoint(_concurrent_locks);
259 if (_out != NULL) {
260 int num_deadlocks = 0;
261 for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) {
262 num_deadlocks++;
263 cycle->print_on(_out);
264 }
265
266 if (num_deadlocks == 1) {
267 _out->print_cr("\nFound 1 deadlock.\n");
268 _out->flush();
269 } else if (num_deadlocks > 1) {
270 _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);
271 _out->flush();
272 }
273 }
274 }
275
276 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
277 int max_depth,
278 bool with_locked_monitors,
279 bool with_locked_synchronizers) {
280 _result = result;
281 _num_threads = 0; // 0 indicates all threads
282 _threads = NULL;
283 _result = result;
284 _max_depth = max_depth;
285 _with_locked_monitors = with_locked_monitors;
286 _with_locked_synchronizers = with_locked_synchronizers;
287 }
288
289 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
290 GrowableArray<instanceHandle>* threads,
291 int num_threads,
292 int max_depth,
293 bool with_locked_monitors,
294 bool with_locked_synchronizers) {
295 _result = result;
296 _num_threads = num_threads;
297 _threads = threads;
298 _result = result;
299 _max_depth = max_depth;
300 _with_locked_monitors = with_locked_monitors;
301 _with_locked_synchronizers = with_locked_synchronizers;
302 }
303
304 bool VM_ThreadDump::doit_prologue() {
305 // Make sure AbstractOwnableSynchronizer is loaded
306 JavaThread* jt = JavaThread::current();
307 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt);
308 if (jt->has_pending_exception()) {
309 return false;
310 }
311
312 if (_with_locked_synchronizers) {
313 // Acquire Heap_lock to dump concurrent locks
314 Heap_lock->lock();
315 }
316
317 return true;
318 }
319
320 void VM_ThreadDump::doit_epilogue() {
321 if (_with_locked_synchronizers) {
322 // Release Heap_lock
323 Heap_lock->unlock();
324 }
325 }
326
327 void VM_ThreadDump::doit() {
328 ResourceMark rm;
329
330 ConcurrentLocksDump concurrent_locks(true);
331 if (_with_locked_synchronizers) {
332 concurrent_locks.dump_at_safepoint();
333 }
334
335 if (_num_threads == 0) {
336 // Snapshot all live threads
337 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
338 if (jt->is_exiting() ||
339 jt->is_hidden_from_external_view()) {
340 // skip terminating threads and hidden threads
341 continue;
342 }
343 ThreadConcurrentLocks* tcl = NULL;
344 if (_with_locked_synchronizers) {
345 tcl = concurrent_locks.thread_concurrent_locks(jt);
346 }
347 ThreadSnapshot* ts = snapshot_thread(jt, tcl);
348 _result->add_thread_snapshot(ts);
349 }
350 } else {
351 // Snapshot threads in the given _threads array
352 // A dummy snapshot is created if a thread doesn't exist
353 for (int i = 0; i < _num_threads; i++) {
354 instanceHandle th = _threads->at(i);
355 if (th() == NULL) {
356 // skip if the thread doesn't exist
357 // Add a dummy snapshot
358 _result->add_thread_snapshot(new ThreadSnapshot());
359 continue;
360 }
361
362 // Dump thread stack only if the thread is alive and not exiting
363 // and not VM internal thread.
364 JavaThread* jt = java_lang_Thread::thread(th());
365 if (jt == NULL || /* thread not alive */
366 jt->is_exiting() ||
367 jt->is_hidden_from_external_view()) {
368 // add a NULL snapshot if skipped
369 _result->add_thread_snapshot(new ThreadSnapshot());
370 continue;
371 }
372 ThreadConcurrentLocks* tcl = NULL;
373 if (_with_locked_synchronizers) {
374 tcl = concurrent_locks.thread_concurrent_locks(jt);
375 }
376 ThreadSnapshot* ts = snapshot_thread(jt, tcl);
377 _result->add_thread_snapshot(ts);
378 }
379 }
380 }
381
382 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) {
383 ThreadSnapshot* snapshot = new ThreadSnapshot(java_thread);
384 snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors);
385 snapshot->set_concurrent_locks(tcl);
386 return snapshot;
387 }
388
389 volatile bool VM_Exit::_vm_exited = false;
390 Thread * VM_Exit::_shutdown_thread = NULL;
391
392 int VM_Exit::set_vm_exited() {
393 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::LastStep);
394
395 Thread * thr_cur = Thread::current();
396
397 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
398
399 int num_active = 0;
400
401 _shutdown_thread = thr_cur;
402 _vm_exited = true; // global flag
403 for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next())
404 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
405 ++num_active;
406 thr->set_terminated(JavaThread::_vm_exited); // per-thread flag
407 }
408
409 return num_active;
410 }
411
412 int VM_Exit::wait_for_threads_in_native_to_block() {
413 // VM exits at safepoint. This function must be called at the final safepoint
414 // to wait for threads in _thread_in_native state to be quiescent.
415 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
416
417 Thread * thr_cur = Thread::current();
418 Monitor timer(Mutex::leaf, "VM_Exit timer", true,
419 Monitor::_safepoint_check_never);
420
421 // Compiler threads need longer wait because they can access VM data directly
422 // while in native. If they are active and some structures being used are
423 // deleted by the shutdown sequence, they will crash. On the other hand, user
424 // threads must go through native=>Java/VM transitions first to access VM
425 // data, and they will be stopped during state transition. In theory, we
426 // don't have to wait for user threads to be quiescent, but it's always
427 // better to terminate VM when current thread is the only active thread, so
428 // wait for user threads too. Numbers are in 10 milliseconds.
429 int max_wait_user_thread = 30; // at least 300 milliseconds
430 int max_wait_compiler_thread = 1000; // at least 10 seconds
431
432 int max_wait = max_wait_compiler_thread;
433
434 int attempts = 0;
435 while (true) {
436 int num_active = 0;
437 int num_active_compiler_thread = 0;
438
439 for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next()) {
440 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
441 num_active++;
442 if (thr->is_Compiler_thread()) {
443 num_active_compiler_thread++;
444 }
445 }
446 }
447
448 if (num_active == 0) {
449 return 0;
450 } else if (attempts > max_wait) {
451 return num_active;
452 } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
453 return num_active;
454 }
455
456 attempts++;
457
458 MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag);
459 timer.wait(Mutex::_no_safepoint_check_flag, 10);
460 }
461 }
462
463 void VM_Exit::doit() {
464 CompileBroker::set_should_block();
465
466 // Wait for a short period for threads in native to block. Any thread
467 // still executing native code after the wait will be stopped at
468 // native==>Java/VM barriers.
469 // Among 16276 JCK tests, 94% of them come here without any threads still
470 // running in native; the other 6% are quiescent within 250ms (Ultra 80).
471 wait_for_threads_in_native_to_block();
472
473 set_vm_exited();
474
475 // cleanup globals resources before exiting. exit_globals() currently
476 // cleans up outputStream resources and PerfMemory resources.
477 exit_globals();
478
479 // Check for exit hook
480 exit_hook_t exit_hook = Arguments::exit_hook();
481 if (exit_hook != NULL) {
482 // exit hook should exit.
483 exit_hook(_exit_code);
484 // ... but if it didn't, we must do it here
485 vm_direct_exit(_exit_code);
486 } else {
487 vm_direct_exit(_exit_code);
488 }
489 }
490
491
492 void VM_Exit::wait_if_vm_exited() {
493 if (_vm_exited &&
494 Thread::current_or_null() != _shutdown_thread) {
495 // _vm_exited is set at safepoint, and the Threads_lock is never released
496 // we will block here until the process dies
497 Threads_lock->lock_without_safepoint_check();
498 ShouldNotReachHere();
499 }
500 }
501
502 void VM_PrintCompileQueue::doit() {
503 CompileBroker::print_compile_queues(_out);
504 }
505
506 #if INCLUDE_SERVICES
507 void VM_PrintClassHierarchy::doit() {
508 KlassHierarchy::print_class_hierarchy(_out, _print_interfaces, _print_subclasses, _classname);
509 }
510 #endif