Thu, 27 May 2010 18:01:56 -0700
6916623: Align object to 16 bytes to use Compressed Oops with java heap up to 64Gb
Summary: Added new product ObjectAlignmentInBytes flag to control object alignment.
Reviewed-by: twisti, ysr, iveresov
1 /*
2 * Copyright 1997-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 # include "incls/_precompiled.incl"
26 # include "incls/_vm_operations.cpp.incl"
28 #define VM_OP_NAME_INITIALIZE(name) #name,
30 const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \
31 { VM_OPS_DO(VM_OP_NAME_INITIALIZE) };
33 void VM_Operation::set_calling_thread(Thread* thread, ThreadPriority priority) {
34 _calling_thread = thread;
35 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
36 _priority = priority;
37 }
40 void VM_Operation::evaluate() {
41 ResourceMark rm;
42 if (TraceVMOperation) {
43 tty->print("[");
44 NOT_PRODUCT(print();)
45 }
46 doit();
47 if (TraceVMOperation) {
48 tty->print_cr("]");
49 }
50 }
52 // Called by fatal error handler.
53 void VM_Operation::print_on_error(outputStream* st) const {
54 st->print("VM_Operation (" PTR_FORMAT "): ", this);
55 st->print("%s", name());
57 const char* mode;
58 switch(evaluation_mode()) {
59 case _safepoint : mode = "safepoint"; break;
60 case _no_safepoint : mode = "no safepoint"; break;
61 case _concurrent : mode = "concurrent"; break;
62 case _async_safepoint: mode = "async safepoint"; break;
63 default : mode = "unknown"; break;
64 }
65 st->print(", mode: %s", mode);
67 if (calling_thread()) {
68 st->print(", requested by thread " PTR_FORMAT, calling_thread());
69 }
70 }
72 void VM_ThreadStop::doit() {
73 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
74 JavaThread* target = java_lang_Thread::thread(target_thread());
75 // Note that this now allows multiple ThreadDeath exceptions to be
76 // thrown at a thread.
77 if (target != NULL) {
78 // the thread has run and is not already in the process of exiting
79 target->send_thread_stop(throwable());
80 }
81 }
83 void VM_Deoptimize::doit() {
84 // We do not want any GCs to happen while we are in the middle of this VM operation
85 ResourceMark rm;
86 DeoptimizationMarker dm;
88 // Deoptimize all activations depending on marked nmethods
89 Deoptimization::deoptimize_dependents();
91 // Make the dependent methods zombies
92 CodeCache::make_marked_nmethods_zombies();
93 }
96 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id) {
97 _thread = thread;
98 _id = id;
99 }
102 void VM_DeoptimizeFrame::doit() {
103 Deoptimization::deoptimize_frame(_thread, _id);
104 }
107 #ifndef PRODUCT
109 void VM_DeoptimizeAll::doit() {
110 DeoptimizationMarker dm;
111 // deoptimize all java threads in the system
112 if (DeoptimizeALot) {
113 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
114 if (thread->has_last_Java_frame()) {
115 thread->deoptimize();
116 }
117 }
118 } else if (DeoptimizeRandom) {
120 // Deoptimize some selected threads and frames
121 int tnum = os::random() & 0x3;
122 int fnum = os::random() & 0x3;
123 int tcount = 0;
124 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
125 if (thread->has_last_Java_frame()) {
126 if (tcount++ == tnum) {
127 tcount = 0;
128 int fcount = 0;
129 // Deoptimize some selected frames.
130 // Biased llocking wants a updated register map
131 for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) {
132 if (fst.current()->can_be_deoptimized()) {
133 if (fcount++ == fnum) {
134 fcount = 0;
135 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map());
136 }
137 }
138 }
139 }
140 }
141 }
142 }
143 }
146 void VM_ZombieAll::doit() {
147 JavaThread *thread = (JavaThread *)calling_thread();
148 assert(thread->is_Java_thread(), "must be a Java thread");
149 thread->make_zombies();
150 }
152 #endif // !PRODUCT
154 void VM_HandleFullCodeCache::doit() {
155 NMethodSweeper::speculative_disconnect_nmethods(_is_full);
156 }
158 void VM_Verify::doit() {
159 Universe::verify();
160 }
162 bool VM_PrintThreads::doit_prologue() {
163 assert(Thread::current()->is_Java_thread(), "just checking");
165 // Make sure AbstractOwnableSynchronizer is loaded
166 if (JDK_Version::is_gte_jdk16x_version()) {
167 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
168 }
170 // Get Heap_lock if concurrent locks will be dumped
171 if (_print_concurrent_locks) {
172 Heap_lock->lock();
173 }
174 return true;
175 }
177 void VM_PrintThreads::doit() {
178 Threads::print_on(_out, true, false, _print_concurrent_locks);
179 }
181 void VM_PrintThreads::doit_epilogue() {
182 if (_print_concurrent_locks) {
183 // Release Heap_lock
184 Heap_lock->unlock();
185 }
186 }
188 void VM_PrintJNI::doit() {
189 JNIHandles::print_on(_out);
190 }
192 VM_FindDeadlocks::~VM_FindDeadlocks() {
193 if (_deadlocks != NULL) {
194 DeadlockCycle* cycle = _deadlocks;
195 while (cycle != NULL) {
196 DeadlockCycle* d = cycle;
197 cycle = cycle->next();
198 delete d;
199 }
200 }
201 }
203 bool VM_FindDeadlocks::doit_prologue() {
204 assert(Thread::current()->is_Java_thread(), "just checking");
206 // Load AbstractOwnableSynchronizer class
207 if (_concurrent_locks && JDK_Version::is_gte_jdk16x_version()) {
208 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
209 }
211 return true;
212 }
214 void VM_FindDeadlocks::doit() {
215 _deadlocks = ThreadService::find_deadlocks_at_safepoint(_concurrent_locks);
216 if (_out != NULL) {
217 int num_deadlocks = 0;
218 for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) {
219 num_deadlocks++;
220 cycle->print_on(_out);
221 }
223 if (num_deadlocks == 1) {
224 _out->print_cr("\nFound 1 deadlock.\n");
225 _out->flush();
226 } else if (num_deadlocks > 1) {
227 _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);
228 _out->flush();
229 }
230 }
231 }
233 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
234 int max_depth,
235 bool with_locked_monitors,
236 bool with_locked_synchronizers) {
237 _result = result;
238 _num_threads = 0; // 0 indicates all threads
239 _threads = NULL;
240 _result = result;
241 _max_depth = max_depth;
242 _with_locked_monitors = with_locked_monitors;
243 _with_locked_synchronizers = with_locked_synchronizers;
244 }
246 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
247 GrowableArray<instanceHandle>* threads,
248 int num_threads,
249 int max_depth,
250 bool with_locked_monitors,
251 bool with_locked_synchronizers) {
252 _result = result;
253 _num_threads = num_threads;
254 _threads = threads;
255 _result = result;
256 _max_depth = max_depth;
257 _with_locked_monitors = with_locked_monitors;
258 _with_locked_synchronizers = with_locked_synchronizers;
259 }
261 bool VM_ThreadDump::doit_prologue() {
262 assert(Thread::current()->is_Java_thread(), "just checking");
264 // Load AbstractOwnableSynchronizer class before taking thread snapshots
265 if (JDK_Version::is_gte_jdk16x_version()) {
266 java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current());
267 }
269 if (_with_locked_synchronizers) {
270 // Acquire Heap_lock to dump concurrent locks
271 Heap_lock->lock();
272 }
274 return true;
275 }
277 void VM_ThreadDump::doit_epilogue() {
278 if (_with_locked_synchronizers) {
279 // Release Heap_lock
280 Heap_lock->unlock();
281 }
282 }
284 void VM_ThreadDump::doit() {
285 ResourceMark rm;
287 ConcurrentLocksDump concurrent_locks(true);
288 if (_with_locked_synchronizers) {
289 concurrent_locks.dump_at_safepoint();
290 }
292 if (_num_threads == 0) {
293 // Snapshot all live threads
294 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
295 if (jt->is_exiting() ||
296 jt->is_hidden_from_external_view()) {
297 // skip terminating threads and hidden threads
298 continue;
299 }
300 ThreadConcurrentLocks* tcl = NULL;
301 if (_with_locked_synchronizers) {
302 tcl = concurrent_locks.thread_concurrent_locks(jt);
303 }
304 ThreadSnapshot* ts = snapshot_thread(jt, tcl);
305 _result->add_thread_snapshot(ts);
306 }
307 } else {
308 // Snapshot threads in the given _threads array
309 // A dummy snapshot is created if a thread doesn't exist
310 for (int i = 0; i < _num_threads; i++) {
311 instanceHandle th = _threads->at(i);
312 if (th() == NULL) {
313 // skip if the thread doesn't exist
314 // Add a dummy snapshot
315 _result->add_thread_snapshot(new ThreadSnapshot());
316 continue;
317 }
319 // Dump thread stack only if the thread is alive and not exiting
320 // and not VM internal thread.
321 JavaThread* jt = java_lang_Thread::thread(th());
322 if (jt == NULL || /* thread not alive */
323 jt->is_exiting() ||
324 jt->is_hidden_from_external_view()) {
325 // add a NULL snapshot if skipped
326 _result->add_thread_snapshot(new ThreadSnapshot());
327 continue;
328 }
329 ThreadConcurrentLocks* tcl = NULL;
330 if (_with_locked_synchronizers) {
331 tcl = concurrent_locks.thread_concurrent_locks(jt);
332 }
333 ThreadSnapshot* ts = snapshot_thread(jt, tcl);
334 _result->add_thread_snapshot(ts);
335 }
336 }
337 }
339 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) {
340 ThreadSnapshot* snapshot = new ThreadSnapshot(java_thread);
341 snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors);
342 snapshot->set_concurrent_locks(tcl);
343 return snapshot;
344 }
346 volatile bool VM_Exit::_vm_exited = false;
347 Thread * VM_Exit::_shutdown_thread = NULL;
349 int VM_Exit::set_vm_exited() {
350 Thread * thr_cur = ThreadLocalStorage::get_thread_slow();
352 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
354 int num_active = 0;
356 _shutdown_thread = thr_cur;
357 _vm_exited = true; // global flag
358 for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next())
359 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
360 ++num_active;
361 thr->set_terminated(JavaThread::_vm_exited); // per-thread flag
362 }
364 return num_active;
365 }
367 int VM_Exit::wait_for_threads_in_native_to_block() {
368 // VM exits at safepoint. This function must be called at the final safepoint
369 // to wait for threads in _thread_in_native state to be quiescent.
370 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
372 Thread * thr_cur = ThreadLocalStorage::get_thread_slow();
373 Monitor timer(Mutex::leaf, "VM_Exit timer", true);
375 // Compiler threads need longer wait because they can access VM data directly
376 // while in native. If they are active and some structures being used are
377 // deleted by the shutdown sequence, they will crash. On the other hand, user
378 // threads must go through native=>Java/VM transitions first to access VM
379 // data, and they will be stopped during state transition. In theory, we
380 // don't have to wait for user threads to be quiescent, but it's always
381 // better to terminate VM when current thread is the only active thread, so
382 // wait for user threads too. Numbers are in 10 milliseconds.
383 int max_wait_user_thread = 30; // at least 300 milliseconds
384 int max_wait_compiler_thread = 1000; // at least 10 seconds
386 int max_wait = max_wait_compiler_thread;
388 int attempts = 0;
389 while (true) {
390 int num_active = 0;
391 int num_active_compiler_thread = 0;
393 for(JavaThread *thr = Threads::first(); thr != NULL; thr = thr->next()) {
394 if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
395 num_active++;
396 if (thr->is_Compiler_thread()) {
397 num_active_compiler_thread++;
398 }
399 }
400 }
402 if (num_active == 0) {
403 return 0;
404 } else if (attempts > max_wait) {
405 return num_active;
406 } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
407 return num_active;
408 }
410 attempts++;
412 MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag);
413 timer.wait(Mutex::_no_safepoint_check_flag, 10);
414 }
415 }
417 void VM_Exit::doit() {
418 CompileBroker::set_should_block();
420 // Wait for a short period for threads in native to block. Any thread
421 // still executing native code after the wait will be stopped at
422 // native==>Java/VM barriers.
423 // Among 16276 JCK tests, 94% of them come here without any threads still
424 // running in native; the other 6% are quiescent within 250ms (Ultra 80).
425 wait_for_threads_in_native_to_block();
427 set_vm_exited();
429 // cleanup globals resources before exiting. exit_globals() currently
430 // cleans up outputStream resources and PerfMemory resources.
431 exit_globals();
433 // Check for exit hook
434 exit_hook_t exit_hook = Arguments::exit_hook();
435 if (exit_hook != NULL) {
436 // exit hook should exit.
437 exit_hook(_exit_code);
438 // ... but if it didn't, we must do it here
439 vm_direct_exit(_exit_code);
440 } else {
441 vm_direct_exit(_exit_code);
442 }
443 }
446 void VM_Exit::wait_if_vm_exited() {
447 if (_vm_exited &&
448 ThreadLocalStorage::get_thread_slow() != _shutdown_thread) {
449 // _vm_exited is set at safepoint, and the Threads_lock is never released
450 // we will block here until the process dies
451 Threads_lock->lock_without_safepoint_check();
452 ShouldNotReachHere();
453 }
454 }