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 "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/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
47const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \
48  { VM_OPS_DO(VM_OP_NAME_INITIALIZE) };
49
50void 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
57void VM_Operation::evaluate() {
58  ResourceMark rm;
59  LogTarget(Debug, vmoperation) lt;
60  if (lt.is_enabled()) {
61    LogStream ls(lt);
62    ls.print("begin ");
63    print_on_error(&ls);
64    ls.cr();
65  }
66  doit();
67  if (lt.is_enabled()) {
68    LogStream ls(lt);
69    ls.print("end ");
70    print_on_error(&ls);
71    ls.cr();
72  }
73}
74
75const 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.
85void 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
97void 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
108void VM_ClearICs::doit() {
109  if (_preserve_static_stubs) {
110    CodeCache::cleanup_inline_caches();
111  } else {
112    CodeCache::clear_inline_caches();
113  }
114}
115
116void 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
128void VM_MarkActiveNMethods::doit() {
129  NMethodSweeper::mark_active_nmethods();
130}
131
132VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id, int reason) {
133  _thread = thread;
134  _id     = id;
135  _reason = reason;
136}
137
138
139void 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
147void 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
184void 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
192void 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
198void VM_Verify::doit() {
199  Universe::heap()->prepare_for_verify();
200  Universe::verify();
201}
202
203bool 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
218void VM_PrintThreads::doit() {
219  Threads::print_on(_out, true, false, _print_concurrent_locks);
220}
221
222void VM_PrintThreads::doit_epilogue() {
223  if (_print_concurrent_locks) {
224    // Release Heap_lock
225    Heap_lock->unlock();
226  }
227}
228
229void VM_PrintJNI::doit() {
230  JNIHandles::print_on(_out);
231}
232
233VM_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
244bool 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
257void 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
276VM_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
289VM_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
304bool 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
320void VM_ThreadDump::doit_epilogue() {
321  if (_with_locked_synchronizers) {
322    // Release Heap_lock
323    Heap_lock->unlock();
324  }
325}
326
327void 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
382ThreadSnapshot* 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
389volatile bool VM_Exit::_vm_exited = false;
390Thread * VM_Exit::_shutdown_thread = NULL;
391
392int VM_Exit::set_vm_exited() {
393
394  Thread * thr_cur = Thread::current();
395
396  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
397
398  int num_active = 0;
399
400  _shutdown_thread = thr_cur;
401  _vm_exited = true;                                // global flag
402  for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next())
403    if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
404      ++num_active;
405      thr->set_terminated(JavaThread::_vm_exited);  // per-thread flag
406    }
407
408  return num_active;
409}
410
411int VM_Exit::wait_for_threads_in_native_to_block() {
412  // VM exits at safepoint. This function must be called at the final safepoint
413  // to wait for threads in _thread_in_native state to be quiescent.
414  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
415
416  Thread * thr_cur = Thread::current();
417  Monitor timer(Mutex::leaf, "VM_Exit timer", true,
418                Monitor::_safepoint_check_never);
419
420  // Compiler threads need longer wait because they can access VM data directly
421  // while in native. If they are active and some structures being used are
422  // deleted by the shutdown sequence, they will crash. On the other hand, user
423  // threads must go through native=>Java/VM transitions first to access VM
424  // data, and they will be stopped during state transition. In theory, we
425  // don't have to wait for user threads to be quiescent, but it's always
426  // better to terminate VM when current thread is the only active thread, so
427  // wait for user threads too. Numbers are in 10 milliseconds.
428  int max_wait_user_thread = 30;                  // at least 300 milliseconds
429  int max_wait_compiler_thread = 1000;            // at least 10 seconds
430
431  int max_wait = max_wait_compiler_thread;
432
433  int attempts = 0;
434  while (true) {
435    int num_active = 0;
436    int num_active_compiler_thread = 0;
437
438    for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next()) {
439      if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
440        num_active++;
441        if (thr->is_Compiler_thread()) {
442          num_active_compiler_thread++;
443        }
444      }
445    }
446
447    if (num_active == 0) {
448       return 0;
449    } else if (attempts > max_wait) {
450       return num_active;
451    } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
452       return num_active;
453    }
454
455    attempts++;
456
457    MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag);
458    timer.wait(Mutex::_no_safepoint_check_flag, 10);
459  }
460}
461
462void VM_Exit::doit() {
463  CompileBroker::set_should_block();
464
465  // Wait for a short period for threads in native to block. Any thread
466  // still executing native code after the wait will be stopped at
467  // native==>Java/VM barriers.
468  // Among 16276 JCK tests, 94% of them come here without any threads still
469  // running in native; the other 6% are quiescent within 250ms (Ultra 80).
470  wait_for_threads_in_native_to_block();
471
472  set_vm_exited();
473
474  // cleanup globals resources before exiting. exit_globals() currently
475  // cleans up outputStream resources and PerfMemory resources.
476  exit_globals();
477
478  // Check for exit hook
479  exit_hook_t exit_hook = Arguments::exit_hook();
480  if (exit_hook != NULL) {
481    // exit hook should exit.
482    exit_hook(_exit_code);
483    // ... but if it didn't, we must do it here
484    vm_direct_exit(_exit_code);
485  } else {
486    vm_direct_exit(_exit_code);
487  }
488}
489
490
491void VM_Exit::wait_if_vm_exited() {
492  if (_vm_exited &&
493      Thread::current_or_null() != _shutdown_thread) {
494    // _vm_exited is set at safepoint, and the Threads_lock is never released
495    // we will block here until the process dies
496    Threads_lock->lock_without_safepoint_check();
497    ShouldNotReachHere();
498  }
499}
500
501void VM_PrintCompileQueue::doit() {
502  CompileBroker::print_compile_queues(_out);
503}
504
505#if INCLUDE_SERVICES
506void VM_PrintClassHierarchy::doit() {
507  KlassHierarchy::print_class_hierarchy(_out, _print_interfaces, _print_subclasses, _classname);
508}
509#endif
510