| /* |
| * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| #include "precompiled.hpp" |
| |
| #include "oops/instanceKlass.hpp" |
| #include "runtime/atomic.hpp" |
| #include "runtime/interfaceSupport.hpp" |
| #include "runtime/mutexLocker.hpp" |
| #include "runtime/safepoint.hpp" |
| #include "runtime/threadCritical.hpp" |
| #include "services/memPtr.hpp" |
| #include "services/memReporter.hpp" |
| #include "services/memTracker.hpp" |
| #include "utilities/decoder.hpp" |
| #include "utilities/globalDefinitions.hpp" |
| |
| bool NMT_track_callsite = false; |
| |
| // walk all 'known' threads at NMT sync point, and collect their recorders |
| void SyncThreadRecorderClosure::do_thread(Thread* thread) { |
| assert(SafepointSynchronize::is_at_safepoint(), "Safepoint required"); |
| if (thread->is_Java_thread()) { |
| JavaThread* javaThread = (JavaThread*)thread; |
| MemRecorder* recorder = javaThread->get_recorder(); |
| if (recorder != NULL) { |
| MemTracker::enqueue_pending_recorder(recorder); |
| javaThread->set_recorder(NULL); |
| } |
| } |
| _thread_count ++; |
| } |
| |
| |
| MemRecorder* MemTracker::_global_recorder = NULL; |
| MemSnapshot* MemTracker::_snapshot = NULL; |
| MemBaseline MemTracker::_baseline; |
| Mutex* MemTracker::_query_lock = NULL; |
| volatile MemRecorder* MemTracker::_merge_pending_queue = NULL; |
| volatile MemRecorder* MemTracker::_pooled_recorders = NULL; |
| MemTrackWorker* MemTracker::_worker_thread = NULL; |
| int MemTracker::_sync_point_skip_count = 0; |
| MemTracker::NMTLevel MemTracker::_tracking_level = MemTracker::NMT_off; |
| volatile MemTracker::NMTStates MemTracker::_state = NMT_uninited; |
| MemTracker::ShutdownReason MemTracker::_reason = NMT_shutdown_none; |
| int MemTracker::_thread_count = 255; |
| volatile jint MemTracker::_pooled_recorder_count = 0; |
| debug_only(intx MemTracker::_main_thread_tid = 0;) |
| NOT_PRODUCT(volatile jint MemTracker::_pending_recorder_count = 0;) |
| |
| void MemTracker::init_tracking_options(const char* option_line) { |
| _tracking_level = NMT_off; |
| if (strcmp(option_line, "=summary") == 0) { |
| _tracking_level = NMT_summary; |
| } else if (strcmp(option_line, "=detail") == 0) { |
| _tracking_level = NMT_detail; |
| } else if (strcmp(option_line, "=off") != 0) { |
| vm_exit_during_initialization("Syntax error, expecting -XX:NativeMemoryTracking=[off|summary|detail]", NULL); |
| } |
| } |
| |
| // first phase of bootstrapping, when VM is still in single-threaded mode. |
| void MemTracker::bootstrap_single_thread() { |
| if (_tracking_level > NMT_off) { |
| assert(_state == NMT_uninited, "wrong state"); |
| |
| // NMT is not supported with UseMallocOnly is on. NMT can NOT |
| // handle the amount of malloc data without significantly impacting |
| // runtime performance when this flag is on. |
| if (UseMallocOnly) { |
| shutdown(NMT_use_malloc_only); |
| return; |
| } |
| |
| _query_lock = new (std::nothrow) Mutex(Monitor::max_nonleaf, "NMT_queryLock"); |
| if (_query_lock == NULL) { |
| shutdown(NMT_out_of_memory); |
| return; |
| } |
| |
| debug_only(_main_thread_tid = os::current_thread_id();) |
| _state = NMT_bootstrapping_single_thread; |
| NMT_track_callsite = (_tracking_level == NMT_detail && can_walk_stack()); |
| } |
| } |
| |
| // second phase of bootstrapping, when VM is about to or already entered multi-theaded mode. |
| void MemTracker::bootstrap_multi_thread() { |
| if (_tracking_level > NMT_off && _state == NMT_bootstrapping_single_thread) { |
| // create nmt lock for multi-thread execution |
| assert(_main_thread_tid == os::current_thread_id(), "wrong thread"); |
| _state = NMT_bootstrapping_multi_thread; |
| NMT_track_callsite = (_tracking_level == NMT_detail && can_walk_stack()); |
| } |
| } |
| |
| // fully start nmt |
| void MemTracker::start() { |
| // Native memory tracking is off from command line option |
| if (_tracking_level == NMT_off || shutdown_in_progress()) return; |
| |
| assert(_main_thread_tid == os::current_thread_id(), "wrong thread"); |
| assert(_state == NMT_bootstrapping_multi_thread, "wrong state"); |
| |
| _snapshot = new (std::nothrow)MemSnapshot(); |
| if (_snapshot != NULL && !_snapshot->out_of_memory()) { |
| if (start_worker()) { |
| _state = NMT_started; |
| NMT_track_callsite = (_tracking_level == NMT_detail && can_walk_stack()); |
| return; |
| } |
| } |
| |
| // fail to start native memory tracking, shut it down |
| shutdown(NMT_initialization); |
| } |
| |
| /** |
| * Shutting down native memory tracking. |
| * We can not shutdown native memory tracking immediately, so we just |
| * setup shutdown pending flag, every native memory tracking component |
| * should orderly shut itself down. |
| * |
| * The shutdown sequences: |
| * 1. MemTracker::shutdown() sets MemTracker to shutdown pending state |
| * 2. Worker thread calls MemTracker::final_shutdown(), which transites |
| * MemTracker to final shutdown state. |
| * 3. At sync point, MemTracker does final cleanup, before sets memory |
| * tracking level to off to complete shutdown. |
| */ |
| void MemTracker::shutdown(ShutdownReason reason) { |
| if (_tracking_level == NMT_off) return; |
| |
| if (_state <= NMT_bootstrapping_single_thread) { |
| // we still in single thread mode, there is not contention |
| _state = NMT_shutdown_pending; |
| _reason = reason; |
| } else { |
| // we want to know who initialized shutdown |
| if ((jint)NMT_started == Atomic::cmpxchg((jint)NMT_shutdown_pending, |
| (jint*)&_state, (jint)NMT_started)) { |
| _reason = reason; |
| } |
| } |
| } |
| |
| // final phase of shutdown |
| void MemTracker::final_shutdown() { |
| // delete all pending recorders and pooled recorders |
| delete_all_pending_recorders(); |
| delete_all_pooled_recorders(); |
| |
| { |
| // shared baseline and snapshot are the only objects needed to |
| // create query results |
| MutexLockerEx locker(_query_lock, true); |
| // cleanup baseline data and snapshot |
| _baseline.clear(); |
| delete _snapshot; |
| _snapshot = NULL; |
| } |
| |
| // shutdown shared decoder instance, since it is only |
| // used by native memory tracking so far. |
| Decoder::shutdown(); |
| |
| MemTrackWorker* worker = NULL; |
| { |
| ThreadCritical tc; |
| // can not delete worker inside the thread critical |
| if (_worker_thread != NULL && Thread::current() == _worker_thread) { |
| worker = _worker_thread; |
| _worker_thread = NULL; |
| } |
| } |
| if (worker != NULL) { |
| delete worker; |
| } |
| _state = NMT_final_shutdown; |
| } |
| |
| // delete all pooled recorders |
| void MemTracker::delete_all_pooled_recorders() { |
| // free all pooled recorders |
| volatile MemRecorder* cur_head = _pooled_recorders; |
| if (cur_head != NULL) { |
| MemRecorder* null_ptr = NULL; |
| while (cur_head != NULL && (void*)cur_head != Atomic::cmpxchg_ptr((void*)null_ptr, |
| (void*)&_pooled_recorders, (void*)cur_head)) { |
| cur_head = _pooled_recorders; |
| } |
| if (cur_head != NULL) { |
| delete cur_head; |
| _pooled_recorder_count = 0; |
| } |
| } |
| } |
| |
| // delete all recorders in pending queue |
| void MemTracker::delete_all_pending_recorders() { |
| // free all pending recorders |
| MemRecorder* pending_head = get_pending_recorders(); |
| if (pending_head != NULL) { |
| delete pending_head; |
| } |
| } |
| |
| /* |
| * retrieve per-thread recorder of specified thread. |
| * if thread == NULL, it means global recorder |
| */ |
| MemRecorder* MemTracker::get_thread_recorder(JavaThread* thread) { |
| if (shutdown_in_progress()) return NULL; |
| |
| MemRecorder* rc; |
| if (thread == NULL) { |
| rc = _global_recorder; |
| } else { |
| rc = thread->get_recorder(); |
| } |
| |
| if (rc != NULL && rc->is_full()) { |
| enqueue_pending_recorder(rc); |
| rc = NULL; |
| } |
| |
| if (rc == NULL) { |
| rc = get_new_or_pooled_instance(); |
| if (thread == NULL) { |
| _global_recorder = rc; |
| } else { |
| thread->set_recorder(rc); |
| } |
| } |
| return rc; |
| } |
| |
| /* |
| * get a per-thread recorder from pool, or create a new one if |
| * there is not one available. |
| */ |
| MemRecorder* MemTracker::get_new_or_pooled_instance() { |
| MemRecorder* cur_head = const_cast<MemRecorder*> (_pooled_recorders); |
| if (cur_head == NULL) { |
| MemRecorder* rec = new (std::nothrow)MemRecorder(); |
| if (rec == NULL || rec->out_of_memory()) { |
| shutdown(NMT_out_of_memory); |
| if (rec != NULL) { |
| delete rec; |
| rec = NULL; |
| } |
| } |
| return rec; |
| } else { |
| MemRecorder* next_head = cur_head->next(); |
| if ((void*)cur_head != Atomic::cmpxchg_ptr((void*)next_head, (void*)&_pooled_recorders, |
| (void*)cur_head)) { |
| return get_new_or_pooled_instance(); |
| } |
| cur_head->set_next(NULL); |
| Atomic::dec(&_pooled_recorder_count); |
| debug_only(cur_head->set_generation();) |
| return cur_head; |
| } |
| } |
| |
| /* |
| * retrieve all recorders in pending queue, and empty the queue |
| */ |
| MemRecorder* MemTracker::get_pending_recorders() { |
| MemRecorder* cur_head = const_cast<MemRecorder*>(_merge_pending_queue); |
| MemRecorder* null_ptr = NULL; |
| while ((void*)cur_head != Atomic::cmpxchg_ptr((void*)null_ptr, (void*)&_merge_pending_queue, |
| (void*)cur_head)) { |
| cur_head = const_cast<MemRecorder*>(_merge_pending_queue); |
| } |
| NOT_PRODUCT(Atomic::store(0, &_pending_recorder_count)); |
| return cur_head; |
| } |
| |
| /* |
| * release a recorder to recorder pool. |
| */ |
| void MemTracker::release_thread_recorder(MemRecorder* rec) { |
| assert(rec != NULL, "null recorder"); |
| // we don't want to pool too many recorders |
| rec->set_next(NULL); |
| if (shutdown_in_progress() || _pooled_recorder_count > _thread_count * 2) { |
| delete rec; |
| return; |
| } |
| |
| rec->clear(); |
| MemRecorder* cur_head = const_cast<MemRecorder*>(_pooled_recorders); |
| rec->set_next(cur_head); |
| while ((void*)cur_head != Atomic::cmpxchg_ptr((void*)rec, (void*)&_pooled_recorders, |
| (void*)cur_head)) { |
| cur_head = const_cast<MemRecorder*>(_pooled_recorders); |
| rec->set_next(cur_head); |
| } |
| Atomic::inc(&_pooled_recorder_count); |
| } |
| |
| /* |
| * This is the most important method in whole nmt implementation. |
| * |
| * Create a memory record. |
| * 1. When nmt is in single-threaded bootstrapping mode, no lock is needed as VM |
| * still in single thread mode. |
| * 2. For all threads other than JavaThread, ThreadCritical is needed |
| * to write to recorders to global recorder. |
| * 3. For JavaThreads that are not longer visible by safepoint, also |
| * need to take ThreadCritical and records are written to global |
| * recorders, since these threads are NOT walked by Threads.do_thread(). |
| * 4. JavaThreads that are running in native state, have to transition |
| * to VM state before writing to per-thread recorders. |
| * 5. JavaThreads that are running in VM state do not need any lock and |
| * records are written to per-thread recorders. |
| * 6. For a thread has yet to attach VM 'Thread', they need to take |
| * ThreadCritical to write to global recorder. |
| * |
| * Important note: |
| * NO LOCK should be taken inside ThreadCritical lock !!! |
| */ |
| void MemTracker::create_memory_record(address addr, MEMFLAGS flags, |
| size_t size, address pc, Thread* thread) { |
| assert(addr != NULL, "Sanity check"); |
| if (!shutdown_in_progress()) { |
| // single thread, we just write records direct to global recorder,' |
| // with any lock |
| if (_state == NMT_bootstrapping_single_thread) { |
| assert(_main_thread_tid == os::current_thread_id(), "wrong thread"); |
| thread = NULL; |
| } else { |
| if (thread == NULL) { |
| // don't use Thread::current(), since it is possible that |
| // the calling thread has yet to attach to VM 'Thread', |
| // which will result assertion failure |
| thread = ThreadLocalStorage::thread(); |
| } |
| } |
| |
| if (thread != NULL) { |
| if (thread->is_Java_thread() && ((JavaThread*)thread)->is_safepoint_visible()) { |
| JavaThread* java_thread = (JavaThread*)thread; |
| JavaThreadState state = java_thread->thread_state(); |
| if (SafepointSynchronize::safepoint_safe(java_thread, state)) { |
| // JavaThreads that are safepoint safe, can run through safepoint, |
| // so ThreadCritical is needed to ensure no threads at safepoint create |
| // new records while the records are being gathered and the sequence number is changing |
| ThreadCritical tc; |
| create_record_in_recorder(addr, flags, size, pc, java_thread); |
| } else { |
| create_record_in_recorder(addr, flags, size, pc, java_thread); |
| } |
| } else { |
| // other threads, such as worker and watcher threads, etc. need to |
| // take ThreadCritical to write to global recorder |
| ThreadCritical tc; |
| create_record_in_recorder(addr, flags, size, pc, NULL); |
| } |
| } else { |
| if (_state == NMT_bootstrapping_single_thread) { |
| // single thread, no lock needed |
| create_record_in_recorder(addr, flags, size, pc, NULL); |
| } else { |
| // for thread has yet to attach VM 'Thread', we can not use VM mutex. |
| // use native thread critical instead |
| ThreadCritical tc; |
| create_record_in_recorder(addr, flags, size, pc, NULL); |
| } |
| } |
| } |
| } |
| |
| // write a record to proper recorder. No lock can be taken from this method |
| // down. |
| void MemTracker::create_record_in_recorder(address addr, MEMFLAGS flags, |
| size_t size, address pc, JavaThread* thread) { |
| |
| MemRecorder* rc = get_thread_recorder(thread); |
| if (rc != NULL) { |
| rc->record(addr, flags, size, pc); |
| } |
| } |
| |
| /** |
| * enqueue a recorder to pending queue |
| */ |
| void MemTracker::enqueue_pending_recorder(MemRecorder* rec) { |
| assert(rec != NULL, "null recorder"); |
| |
| // we are shutting down, so just delete it |
| if (shutdown_in_progress()) { |
| rec->set_next(NULL); |
| delete rec; |
| return; |
| } |
| |
| MemRecorder* cur_head = const_cast<MemRecorder*>(_merge_pending_queue); |
| rec->set_next(cur_head); |
| while ((void*)cur_head != Atomic::cmpxchg_ptr((void*)rec, (void*)&_merge_pending_queue, |
| (void*)cur_head)) { |
| cur_head = const_cast<MemRecorder*>(_merge_pending_queue); |
| rec->set_next(cur_head); |
| } |
| NOT_PRODUCT(Atomic::inc(&_pending_recorder_count);) |
| } |
| |
| /* |
| * The method is called at global safepoint |
| * during it synchronization process. |
| * 1. enqueue all JavaThreads' per-thread recorders |
| * 2. enqueue global recorder |
| * 3. retrieve all pending recorders |
| * 4. reset global sequence number generator |
| * 5. call worker's sync |
| */ |
| #define MAX_SAFEPOINTS_TO_SKIP 128 |
| #define SAFE_SEQUENCE_THRESHOLD 30 |
| #define HIGH_GENERATION_THRESHOLD 60 |
| |
| void MemTracker::sync() { |
| assert(_tracking_level > NMT_off, "NMT is not enabled"); |
| assert(SafepointSynchronize::is_at_safepoint(), "Safepoint required"); |
| |
| // Some GC tests hit large number of safepoints in short period of time |
| // without meaningful activities. We should prevent going to |
| // sync point in these cases, which can potentially exhaust generation buffer. |
| // Here is the factots to determine if we should go into sync point: |
| // 1. not to overflow sequence number |
| // 2. if we are in danger to overflow generation buffer |
| // 3. how many safepoints we already skipped sync point |
| if (_state == NMT_started) { |
| // worker thread is not ready, no one can manage generation |
| // buffer, so skip this safepoint |
| if (_worker_thread == NULL) return; |
| |
| if (_sync_point_skip_count < MAX_SAFEPOINTS_TO_SKIP) { |
| int per_seq_in_use = SequenceGenerator::peek() * 100 / max_jint; |
| int per_gen_in_use = _worker_thread->generations_in_use() * 100 / MAX_GENERATIONS; |
| if (per_seq_in_use < SAFE_SEQUENCE_THRESHOLD && per_gen_in_use >= HIGH_GENERATION_THRESHOLD) { |
| _sync_point_skip_count ++; |
| return; |
| } |
| } |
| _sync_point_skip_count = 0; |
| { |
| // This method is running at safepoint, with ThreadCritical lock, |
| // it should guarantee that NMT is fully sync-ed. |
| ThreadCritical tc; |
| |
| SequenceGenerator::reset(); |
| |
| // walk all JavaThreads to collect recorders |
| SyncThreadRecorderClosure stc; |
| Threads::threads_do(&stc); |
| |
| _thread_count = stc.get_thread_count(); |
| MemRecorder* pending_recorders = get_pending_recorders(); |
| |
| if (_global_recorder != NULL) { |
| _global_recorder->set_next(pending_recorders); |
| pending_recorders = _global_recorder; |
| _global_recorder = NULL; |
| } |
| // check _worker_thread with lock to avoid racing condition |
| if (_worker_thread != NULL) { |
| _worker_thread->at_sync_point(pending_recorders, InstanceKlass::number_of_instance_classes()); |
| } |
| |
| assert(SequenceGenerator::peek() == 1, "Should not have memory activities during sync-point"); |
| } |
| } |
| |
| // now, it is the time to shut whole things off |
| if (_state == NMT_final_shutdown) { |
| // walk all JavaThreads to delete all recorders |
| SyncThreadRecorderClosure stc; |
| Threads::threads_do(&stc); |
| // delete global recorder |
| { |
| ThreadCritical tc; |
| if (_global_recorder != NULL) { |
| delete _global_recorder; |
| _global_recorder = NULL; |
| } |
| } |
| MemRecorder* pending_recorders = get_pending_recorders(); |
| if (pending_recorders != NULL) { |
| delete pending_recorders; |
| } |
| // try at a later sync point to ensure MemRecorder instance drops to zero to |
| // completely shutdown NMT |
| if (MemRecorder::_instance_count == 0) { |
| _state = NMT_shutdown; |
| _tracking_level = NMT_off; |
| } |
| } |
| } |
| |
| /* |
| * Start worker thread. |
| */ |
| bool MemTracker::start_worker() { |
| assert(_worker_thread == NULL, "Just Check"); |
| _worker_thread = new (std::nothrow) MemTrackWorker(); |
| if (_worker_thread == NULL || _worker_thread->has_error()) { |
| shutdown(NMT_initialization); |
| return false; |
| } |
| _worker_thread->start(); |
| return true; |
| } |
| |
| /* |
| * We need to collect a JavaThread's per-thread recorder |
| * before it exits. |
| */ |
| void MemTracker::thread_exiting(JavaThread* thread) { |
| if (is_on()) { |
| MemRecorder* rec = thread->get_recorder(); |
| if (rec != NULL) { |
| enqueue_pending_recorder(rec); |
| thread->set_recorder(NULL); |
| } |
| } |
| } |
| |
| // baseline current memory snapshot |
| bool MemTracker::baseline() { |
| MutexLockerEx lock(_query_lock, true); |
| MemSnapshot* snapshot = get_snapshot(); |
| if (snapshot != NULL) { |
| return _baseline.baseline(*snapshot, false); |
| } |
| return false; |
| } |
| |
| // print memory usage from current snapshot |
| bool MemTracker::print_memory_usage(BaselineOutputer& out, size_t unit, bool summary_only) { |
| MemBaseline baseline; |
| MutexLockerEx lock(_query_lock, true); |
| MemSnapshot* snapshot = get_snapshot(); |
| if (snapshot != NULL && baseline.baseline(*snapshot, summary_only)) { |
| BaselineReporter reporter(out, unit); |
| reporter.report_baseline(baseline, summary_only); |
| return true; |
| } |
| return false; |
| } |
| |
| // compare memory usage between current snapshot and baseline |
| bool MemTracker::compare_memory_usage(BaselineOutputer& out, size_t unit, bool summary_only) { |
| MutexLockerEx lock(_query_lock, true); |
| if (_baseline.baselined()) { |
| MemBaseline baseline; |
| MemSnapshot* snapshot = get_snapshot(); |
| if (snapshot != NULL && baseline.baseline(*snapshot, summary_only)) { |
| BaselineReporter reporter(out, unit); |
| reporter.diff_baselines(baseline, _baseline, summary_only); |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| #ifndef PRODUCT |
| void MemTracker::walk_stack(int toSkip, char* buf, int len) { |
| int cur_len = 0; |
| char tmp[1024]; |
| address pc; |
| |
| while (cur_len < len) { |
| pc = os::get_caller_pc(toSkip + 1); |
| if (pc != NULL && os::dll_address_to_function_name(pc, tmp, sizeof(tmp), NULL)) { |
| jio_snprintf(&buf[cur_len], (len - cur_len), "%s\n", tmp); |
| cur_len = (int)strlen(buf); |
| } else { |
| buf[cur_len] = '\0'; |
| break; |
| } |
| toSkip ++; |
| } |
| } |
| |
| void MemTracker::print_tracker_stats(outputStream* st) { |
| st->print_cr("\nMemory Tracker Stats:"); |
| st->print_cr("\tMax sequence number = %d", SequenceGenerator::max_seq_num()); |
| st->print_cr("\tthead count = %d", _thread_count); |
| st->print_cr("\tArena instance = %d", Arena::_instance_count); |
| st->print_cr("\tpooled recorder count = %d", _pooled_recorder_count); |
| st->print_cr("\tqueued recorder count = %d", _pending_recorder_count); |
| st->print_cr("\tmemory recorder instance count = %d", MemRecorder::_instance_count); |
| if (_worker_thread != NULL) { |
| st->print_cr("\tWorker thread:"); |
| st->print_cr("\t\tSync point count = %d", _worker_thread->_sync_point_count); |
| st->print_cr("\t\tpending recorder count = %d", _worker_thread->count_pending_recorders()); |
| st->print_cr("\t\tmerge count = %d", _worker_thread->_merge_count); |
| } else { |
| st->print_cr("\tWorker thread is not started"); |
| } |
| st->print_cr(" "); |
| |
| if (_snapshot != NULL) { |
| _snapshot->print_snapshot_stats(st); |
| } else { |
| st->print_cr("No snapshot"); |
| } |
| } |
| #endif |
| |