Tue, 09 Oct 2012 10:09:34 -0700
7197424: update copyright year to match last edit in jdk8 hotspot repository
Summary: Update copyright year to 2012 for relevant files
Reviewed-by: dholmes, coleenp
1 /*
2 * Copyright (c) 2012, 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 #include "precompiled.hpp"
26 #include "runtime/atomic.hpp"
27 #include "runtime/interfaceSupport.hpp"
28 #include "runtime/mutexLocker.hpp"
29 #include "runtime/safepoint.hpp"
30 #include "runtime/threadCritical.hpp"
31 #include "services/memPtr.hpp"
32 #include "services/memReporter.hpp"
33 #include "services/memTracker.hpp"
34 #include "utilities/decoder.hpp"
35 #include "utilities/globalDefinitions.hpp"
37 bool NMT_track_callsite = false;
39 // walk all 'known' threads at NMT sync point, and collect their recorders
40 void SyncThreadRecorderClosure::do_thread(Thread* thread) {
41 assert(SafepointSynchronize::is_at_safepoint(), "Safepoint required");
42 if (thread->is_Java_thread()) {
43 JavaThread* javaThread = (JavaThread*)thread;
44 MemRecorder* recorder = javaThread->get_recorder();
45 if (recorder != NULL) {
46 MemTracker::enqueue_pending_recorder(recorder);
47 javaThread->set_recorder(NULL);
48 }
49 }
50 _thread_count ++;
51 }
54 MemRecorder* MemTracker::_global_recorder = NULL;
55 MemSnapshot* MemTracker::_snapshot = NULL;
56 MemBaseline MemTracker::_baseline;
57 Mutex* MemTracker::_query_lock = NULL;
58 volatile MemRecorder* MemTracker::_merge_pending_queue = NULL;
59 volatile MemRecorder* MemTracker::_pooled_recorders = NULL;
60 MemTrackWorker* MemTracker::_worker_thread = NULL;
61 int MemTracker::_sync_point_skip_count = 0;
62 MemTracker::NMTLevel MemTracker::_tracking_level = MemTracker::NMT_off;
63 volatile MemTracker::NMTStates MemTracker::_state = NMT_uninited;
64 MemTracker::ShutdownReason MemTracker::_reason = NMT_shutdown_none;
65 int MemTracker::_thread_count = 255;
66 volatile jint MemTracker::_pooled_recorder_count = 0;
67 debug_only(intx MemTracker::_main_thread_tid = 0;)
68 NOT_PRODUCT(volatile jint MemTracker::_pending_recorder_count = 0;)
70 void MemTracker::init_tracking_options(const char* option_line) {
71 _tracking_level = NMT_off;
72 if (strncmp(option_line, "=summary", 8) == 0) {
73 _tracking_level = NMT_summary;
74 } else if (strncmp(option_line, "=detail", 7) == 0) {
75 _tracking_level = NMT_detail;
76 } else {
77 char msg[255];
78 //+1 to remove the '=' character
79 jio_snprintf(msg, 255, "Unknown option given to XX:NativeMemoryTracking: %s", option_line+1);
80 vm_exit_during_initialization(msg, NULL);
81 }
82 }
84 // first phase of bootstrapping, when VM is still in single-threaded mode.
85 void MemTracker::bootstrap_single_thread() {
86 if (_tracking_level > NMT_off) {
87 assert(_state == NMT_uninited, "wrong state");
89 // NMT is not supported with UseMallocOnly is on. NMT can NOT
90 // handle the amount of malloc data without significantly impacting
91 // runtime performance when this flag is on.
92 if (UseMallocOnly) {
93 shutdown(NMT_use_malloc_only);
94 return;
95 }
97 _query_lock = new (std::nothrow) Mutex(Monitor::max_nonleaf, "NMT_queryLock");
98 if (_query_lock == NULL) {
99 shutdown(NMT_out_of_memory);
100 return;
101 }
103 debug_only(_main_thread_tid = os::current_thread_id();)
104 _state = NMT_bootstrapping_single_thread;
105 NMT_track_callsite = (_tracking_level == NMT_detail && can_walk_stack());
106 }
107 }
109 // second phase of bootstrapping, when VM is about to or already entered multi-theaded mode.
110 void MemTracker::bootstrap_multi_thread() {
111 if (_tracking_level > NMT_off && _state == NMT_bootstrapping_single_thread) {
112 // create nmt lock for multi-thread execution
113 assert(_main_thread_tid == os::current_thread_id(), "wrong thread");
114 _state = NMT_bootstrapping_multi_thread;
115 NMT_track_callsite = (_tracking_level == NMT_detail && can_walk_stack());
116 }
117 }
119 // fully start nmt
120 void MemTracker::start() {
121 // Native memory tracking is off from command line option
122 if (_tracking_level == NMT_off || shutdown_in_progress()) return;
124 assert(_main_thread_tid == os::current_thread_id(), "wrong thread");
125 assert(_state == NMT_bootstrapping_multi_thread, "wrong state");
127 _snapshot = new (std::nothrow)MemSnapshot();
128 if (_snapshot != NULL && !_snapshot->out_of_memory()) {
129 if (start_worker()) {
130 _state = NMT_started;
131 NMT_track_callsite = (_tracking_level == NMT_detail && can_walk_stack());
132 return;
133 }
134 }
136 // fail to start native memory tracking, shut it down
137 shutdown(NMT_initialization);
138 }
140 /**
141 * Shutting down native memory tracking.
142 * We can not shutdown native memory tracking immediately, so we just
143 * setup shutdown pending flag, every native memory tracking component
144 * should orderly shut itself down.
145 *
146 * The shutdown sequences:
147 * 1. MemTracker::shutdown() sets MemTracker to shutdown pending state
148 * 2. Worker thread calls MemTracker::final_shutdown(), which transites
149 * MemTracker to final shutdown state.
150 * 3. At sync point, MemTracker does final cleanup, before sets memory
151 * tracking level to off to complete shutdown.
152 */
153 void MemTracker::shutdown(ShutdownReason reason) {
154 if (_tracking_level == NMT_off) return;
156 if (_state <= NMT_bootstrapping_single_thread) {
157 // we still in single thread mode, there is not contention
158 _state = NMT_shutdown_pending;
159 _reason = reason;
160 } else {
161 // we want to know who initialized shutdown
162 if ((jint)NMT_started == Atomic::cmpxchg((jint)NMT_shutdown_pending,
163 (jint*)&_state, (jint)NMT_started)) {
164 _reason = reason;
165 }
166 }
167 }
169 // final phase of shutdown
170 void MemTracker::final_shutdown() {
171 // delete all pending recorders and pooled recorders
172 delete_all_pending_recorders();
173 delete_all_pooled_recorders();
175 {
176 // shared baseline and snapshot are the only objects needed to
177 // create query results
178 MutexLockerEx locker(_query_lock, true);
179 // cleanup baseline data and snapshot
180 _baseline.clear();
181 delete _snapshot;
182 _snapshot = NULL;
183 }
185 // shutdown shared decoder instance, since it is only
186 // used by native memory tracking so far.
187 Decoder::shutdown();
189 MemTrackWorker* worker = NULL;
190 {
191 ThreadCritical tc;
192 // can not delete worker inside the thread critical
193 if (_worker_thread != NULL && Thread::current() == _worker_thread) {
194 worker = _worker_thread;
195 _worker_thread = NULL;
196 }
197 }
198 if (worker != NULL) {
199 delete worker;
200 }
201 _state = NMT_final_shutdown;
202 }
204 // delete all pooled recorders
205 void MemTracker::delete_all_pooled_recorders() {
206 // free all pooled recorders
207 volatile MemRecorder* cur_head = _pooled_recorders;
208 if (cur_head != NULL) {
209 MemRecorder* null_ptr = NULL;
210 while (cur_head != NULL && (void*)cur_head != Atomic::cmpxchg_ptr((void*)null_ptr,
211 (void*)&_pooled_recorders, (void*)cur_head)) {
212 cur_head = _pooled_recorders;
213 }
214 if (cur_head != NULL) {
215 delete cur_head;
216 _pooled_recorder_count = 0;
217 }
218 }
219 }
221 // delete all recorders in pending queue
222 void MemTracker::delete_all_pending_recorders() {
223 // free all pending recorders
224 MemRecorder* pending_head = get_pending_recorders();
225 if (pending_head != NULL) {
226 delete pending_head;
227 }
228 }
230 /*
231 * retrieve per-thread recorder of specified thread.
232 * if thread == NULL, it means global recorder
233 */
234 MemRecorder* MemTracker::get_thread_recorder(JavaThread* thread) {
235 if (shutdown_in_progress()) return NULL;
237 MemRecorder* rc;
238 if (thread == NULL) {
239 rc = _global_recorder;
240 } else {
241 rc = thread->get_recorder();
242 }
244 if (rc != NULL && rc->is_full()) {
245 enqueue_pending_recorder(rc);
246 rc = NULL;
247 }
249 if (rc == NULL) {
250 rc = get_new_or_pooled_instance();
251 if (thread == NULL) {
252 _global_recorder = rc;
253 } else {
254 thread->set_recorder(rc);
255 }
256 }
257 return rc;
258 }
260 /*
261 * get a per-thread recorder from pool, or create a new one if
262 * there is not one available.
263 */
264 MemRecorder* MemTracker::get_new_or_pooled_instance() {
265 MemRecorder* cur_head = const_cast<MemRecorder*> (_pooled_recorders);
266 if (cur_head == NULL) {
267 MemRecorder* rec = new (std::nothrow)MemRecorder();
268 if (rec == NULL || rec->out_of_memory()) {
269 shutdown(NMT_out_of_memory);
270 if (rec != NULL) {
271 delete rec;
272 rec = NULL;
273 }
274 }
275 return rec;
276 } else {
277 MemRecorder* next_head = cur_head->next();
278 if ((void*)cur_head != Atomic::cmpxchg_ptr((void*)next_head, (void*)&_pooled_recorders,
279 (void*)cur_head)) {
280 return get_new_or_pooled_instance();
281 }
282 cur_head->set_next(NULL);
283 Atomic::dec(&_pooled_recorder_count);
284 debug_only(cur_head->set_generation();)
285 return cur_head;
286 }
287 }
289 /*
290 * retrieve all recorders in pending queue, and empty the queue
291 */
292 MemRecorder* MemTracker::get_pending_recorders() {
293 MemRecorder* cur_head = const_cast<MemRecorder*>(_merge_pending_queue);
294 MemRecorder* null_ptr = NULL;
295 while ((void*)cur_head != Atomic::cmpxchg_ptr((void*)null_ptr, (void*)&_merge_pending_queue,
296 (void*)cur_head)) {
297 cur_head = const_cast<MemRecorder*>(_merge_pending_queue);
298 }
299 NOT_PRODUCT(Atomic::store(0, &_pending_recorder_count));
300 return cur_head;
301 }
303 /*
304 * release a recorder to recorder pool.
305 */
306 void MemTracker::release_thread_recorder(MemRecorder* rec) {
307 assert(rec != NULL, "null recorder");
308 // we don't want to pool too many recorders
309 rec->set_next(NULL);
310 if (shutdown_in_progress() || _pooled_recorder_count > _thread_count * 2) {
311 delete rec;
312 return;
313 }
315 rec->clear();
316 MemRecorder* cur_head = const_cast<MemRecorder*>(_pooled_recorders);
317 rec->set_next(cur_head);
318 while ((void*)cur_head != Atomic::cmpxchg_ptr((void*)rec, (void*)&_pooled_recorders,
319 (void*)cur_head)) {
320 cur_head = const_cast<MemRecorder*>(_pooled_recorders);
321 rec->set_next(cur_head);
322 }
323 Atomic::inc(&_pooled_recorder_count);
324 }
326 /*
327 * This is the most important method in whole nmt implementation.
328 *
329 * Create a memory record.
330 * 1. When nmt is in single-threaded bootstrapping mode, no lock is needed as VM
331 * still in single thread mode.
332 * 2. For all threads other than JavaThread, ThreadCritical is needed
333 * to write to recorders to global recorder.
334 * 3. For JavaThreads that are not longer visible by safepoint, also
335 * need to take ThreadCritical and records are written to global
336 * recorders, since these threads are NOT walked by Threads.do_thread().
337 * 4. JavaThreads that are running in native state, have to transition
338 * to VM state before writing to per-thread recorders.
339 * 5. JavaThreads that are running in VM state do not need any lock and
340 * records are written to per-thread recorders.
341 * 6. For a thread has yet to attach VM 'Thread', they need to take
342 * ThreadCritical to write to global recorder.
343 *
344 * Important note:
345 * NO LOCK should be taken inside ThreadCritical lock !!!
346 */
347 void MemTracker::create_memory_record(address addr, MEMFLAGS flags,
348 size_t size, address pc, Thread* thread) {
349 assert(addr != NULL, "Sanity check");
350 if (!shutdown_in_progress()) {
351 // single thread, we just write records direct to global recorder,'
352 // with any lock
353 if (_state == NMT_bootstrapping_single_thread) {
354 assert(_main_thread_tid == os::current_thread_id(), "wrong thread");
355 thread = NULL;
356 } else {
357 if (thread == NULL) {
358 // don't use Thread::current(), since it is possible that
359 // the calling thread has yet to attach to VM 'Thread',
360 // which will result assertion failure
361 thread = ThreadLocalStorage::thread();
362 }
363 }
365 if (thread != NULL) {
366 if (thread->is_Java_thread() && ((JavaThread*)thread)->is_safepoint_visible()) {
367 JavaThread* java_thread = static_cast<JavaThread*>(thread);
368 JavaThreadState state = java_thread->thread_state();
369 if (SafepointSynchronize::safepoint_safe(java_thread, state)) {
370 // JavaThreads that are safepoint safe, can run through safepoint,
371 // so ThreadCritical is needed to ensure no threads at safepoint create
372 // new records while the records are being gathered and the sequence number is changing
373 ThreadCritical tc;
374 create_record_in_recorder(addr, flags, size, pc, java_thread);
375 } else {
376 create_record_in_recorder(addr, flags, size, pc, java_thread);
377 }
378 } else {
379 // other threads, such as worker and watcher threads, etc. need to
380 // take ThreadCritical to write to global recorder
381 ThreadCritical tc;
382 create_record_in_recorder(addr, flags, size, pc, NULL);
383 }
384 } else {
385 if (_state == NMT_bootstrapping_single_thread) {
386 // single thread, no lock needed
387 create_record_in_recorder(addr, flags, size, pc, NULL);
388 } else {
389 // for thread has yet to attach VM 'Thread', we can not use VM mutex.
390 // use native thread critical instead
391 ThreadCritical tc;
392 create_record_in_recorder(addr, flags, size, pc, NULL);
393 }
394 }
395 }
396 }
398 // write a record to proper recorder. No lock can be taken from this method
399 // down.
400 void MemTracker::create_record_in_recorder(address addr, MEMFLAGS flags,
401 size_t size, address pc, JavaThread* thread) {
403 MemRecorder* rc = get_thread_recorder(thread);
404 if (rc != NULL) {
405 rc->record(addr, flags, size, pc);
406 }
407 }
409 /**
410 * enqueue a recorder to pending queue
411 */
412 void MemTracker::enqueue_pending_recorder(MemRecorder* rec) {
413 assert(rec != NULL, "null recorder");
415 // we are shutting down, so just delete it
416 if (shutdown_in_progress()) {
417 rec->set_next(NULL);
418 delete rec;
419 return;
420 }
422 MemRecorder* cur_head = const_cast<MemRecorder*>(_merge_pending_queue);
423 rec->set_next(cur_head);
424 while ((void*)cur_head != Atomic::cmpxchg_ptr((void*)rec, (void*)&_merge_pending_queue,
425 (void*)cur_head)) {
426 cur_head = const_cast<MemRecorder*>(_merge_pending_queue);
427 rec->set_next(cur_head);
428 }
429 NOT_PRODUCT(Atomic::inc(&_pending_recorder_count);)
430 }
432 /*
433 * The method is called at global safepoint
434 * during it synchronization process.
435 * 1. enqueue all JavaThreads' per-thread recorders
436 * 2. enqueue global recorder
437 * 3. retrieve all pending recorders
438 * 4. reset global sequence number generator
439 * 5. call worker's sync
440 */
441 #define MAX_SAFEPOINTS_TO_SKIP 128
442 #define SAFE_SEQUENCE_THRESHOLD 30
443 #define HIGH_GENERATION_THRESHOLD 60
445 void MemTracker::sync() {
446 assert(_tracking_level > NMT_off, "NMT is not enabled");
447 assert(SafepointSynchronize::is_at_safepoint(), "Safepoint required");
449 // Some GC tests hit large number of safepoints in short period of time
450 // without meaningful activities. We should prevent going to
451 // sync point in these cases, which can potentially exhaust generation buffer.
452 // Here is the factots to determine if we should go into sync point:
453 // 1. not to overflow sequence number
454 // 2. if we are in danger to overflow generation buffer
455 // 3. how many safepoints we already skipped sync point
456 if (_state == NMT_started) {
457 // worker thread is not ready, no one can manage generation
458 // buffer, so skip this safepoint
459 if (_worker_thread == NULL) return;
461 if (_sync_point_skip_count < MAX_SAFEPOINTS_TO_SKIP) {
462 int per_seq_in_use = SequenceGenerator::peek() * 100 / max_jint;
463 int per_gen_in_use = _worker_thread->generations_in_use() * 100 / MAX_GENERATIONS;
464 if (per_seq_in_use < SAFE_SEQUENCE_THRESHOLD && per_gen_in_use >= HIGH_GENERATION_THRESHOLD) {
465 _sync_point_skip_count ++;
466 return;
467 }
468 }
469 _sync_point_skip_count = 0;
470 {
471 // This method is running at safepoint, with ThreadCritical lock,
472 // it should guarantee that NMT is fully sync-ed.
473 ThreadCritical tc;
475 // walk all JavaThreads to collect recorders
476 SyncThreadRecorderClosure stc;
477 Threads::threads_do(&stc);
479 _thread_count = stc.get_thread_count();
480 MemRecorder* pending_recorders = get_pending_recorders();
482 if (_global_recorder != NULL) {
483 _global_recorder->set_next(pending_recorders);
484 pending_recorders = _global_recorder;
485 _global_recorder = NULL;
486 }
487 SequenceGenerator::reset();
488 // check _worker_thread with lock to avoid racing condition
489 if (_worker_thread != NULL) {
490 _worker_thread->at_sync_point(pending_recorders);
491 }
492 }
493 }
495 // now, it is the time to shut whole things off
496 if (_state == NMT_final_shutdown) {
497 // walk all JavaThreads to delete all recorders
498 SyncThreadRecorderClosure stc;
499 Threads::threads_do(&stc);
500 // delete global recorder
501 {
502 ThreadCritical tc;
503 if (_global_recorder != NULL) {
504 delete _global_recorder;
505 _global_recorder = NULL;
506 }
507 }
508 MemRecorder* pending_recorders = get_pending_recorders();
509 if (pending_recorders != NULL) {
510 delete pending_recorders;
511 }
512 // try at a later sync point to ensure MemRecorder instance drops to zero to
513 // completely shutdown NMT
514 if (MemRecorder::_instance_count == 0) {
515 _state = NMT_shutdown;
516 _tracking_level = NMT_off;
517 }
518 }
519 }
521 /*
522 * Start worker thread.
523 */
524 bool MemTracker::start_worker() {
525 assert(_worker_thread == NULL, "Just Check");
526 _worker_thread = new (std::nothrow) MemTrackWorker();
527 if (_worker_thread == NULL || _worker_thread->has_error()) {
528 shutdown(NMT_initialization);
529 return false;
530 }
531 _worker_thread->start();
532 return true;
533 }
535 /*
536 * We need to collect a JavaThread's per-thread recorder
537 * before it exits.
538 */
539 void MemTracker::thread_exiting(JavaThread* thread) {
540 if (is_on()) {
541 MemRecorder* rec = thread->get_recorder();
542 if (rec != NULL) {
543 enqueue_pending_recorder(rec);
544 thread->set_recorder(NULL);
545 }
546 }
547 }
549 // baseline current memory snapshot
550 bool MemTracker::baseline() {
551 MutexLockerEx lock(_query_lock, true);
552 MemSnapshot* snapshot = get_snapshot();
553 if (snapshot != NULL) {
554 return _baseline.baseline(*snapshot, false);
555 }
556 return false;
557 }
559 // print memory usage from current snapshot
560 bool MemTracker::print_memory_usage(BaselineOutputer& out, size_t unit, bool summary_only) {
561 MemBaseline baseline;
562 MutexLockerEx lock(_query_lock, true);
563 MemSnapshot* snapshot = get_snapshot();
564 if (snapshot != NULL && baseline.baseline(*snapshot, summary_only)) {
565 BaselineReporter reporter(out, unit);
566 reporter.report_baseline(baseline, summary_only);
567 return true;
568 }
569 return false;
570 }
572 // compare memory usage between current snapshot and baseline
573 bool MemTracker::compare_memory_usage(BaselineOutputer& out, size_t unit, bool summary_only) {
574 MutexLockerEx lock(_query_lock, true);
575 if (_baseline.baselined()) {
576 MemBaseline baseline;
577 MemSnapshot* snapshot = get_snapshot();
578 if (snapshot != NULL && baseline.baseline(*snapshot, summary_only)) {
579 BaselineReporter reporter(out, unit);
580 reporter.diff_baselines(baseline, _baseline, summary_only);
581 return true;
582 }
583 }
584 return false;
585 }
587 #ifndef PRODUCT
588 void MemTracker::walk_stack(int toSkip, char* buf, int len) {
589 int cur_len = 0;
590 char tmp[1024];
591 address pc;
593 while (cur_len < len) {
594 pc = os::get_caller_pc(toSkip + 1);
595 if (pc != NULL && os::dll_address_to_function_name(pc, tmp, sizeof(tmp), NULL)) {
596 jio_snprintf(&buf[cur_len], (len - cur_len), "%s\n", tmp);
597 cur_len = (int)strlen(buf);
598 } else {
599 buf[cur_len] = '\0';
600 break;
601 }
602 toSkip ++;
603 }
604 }
606 void MemTracker::print_tracker_stats(outputStream* st) {
607 st->print_cr("\nMemory Tracker Stats:");
608 st->print_cr("\tMax sequence number = %d", SequenceGenerator::max_seq_num());
609 st->print_cr("\tthead count = %d", _thread_count);
610 st->print_cr("\tArena instance = %d", Arena::_instance_count);
611 st->print_cr("\tpooled recorder count = %d", _pooled_recorder_count);
612 st->print_cr("\tqueued recorder count = %d", _pending_recorder_count);
613 st->print_cr("\tmemory recorder instance count = %d", MemRecorder::_instance_count);
614 if (_worker_thread != NULL) {
615 st->print_cr("\tWorker thread:");
616 st->print_cr("\t\tSync point count = %d", _worker_thread->_sync_point_count);
617 st->print_cr("\t\tpending recorder count = %d", _worker_thread->count_pending_recorders());
618 st->print_cr("\t\tmerge count = %d", _worker_thread->_merge_count);
619 } else {
620 st->print_cr("\tWorker thread is not started");
621 }
622 st->print_cr(" ");
624 if (_snapshot != NULL) {
625 _snapshot->print_snapshot_stats(st);
626 } else {
627 st->print_cr("No snapshot");
628 }
629 }
630 #endif