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