| /* |
| * Copyright (c) 2012, 2013, 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 "runtime/thread.inline.hpp" |
| #include "runtime/vm_operations.hpp" |
| #include "services/memPtr.hpp" |
| #include "services/memReporter.hpp" |
| #include "services/memTracker.hpp" |
| #include "utilities/decoder.hpp" |
| #include "utilities/defaultStream.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* volatile MemTracker::_global_recorder = NULL; |
| MemSnapshot* MemTracker::_snapshot = NULL; |
| MemBaseline MemTracker::_baseline; |
| Mutex* MemTracker::_query_lock = NULL; |
| MemRecorder* volatile MemTracker::_merge_pending_queue = NULL; |
| MemRecorder* volatile 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; |
| volatile unsigned long MemTracker::_processing_generation = 0; |
| volatile bool MemTracker::_worker_thread_idle = false; |
| volatile jint MemTracker::_pending_op_count = 0; |
| volatile bool MemTracker::_slowdown_calling_thread = false; |
| 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) { |
| // detail relies on a stack-walking ability that may not |
| // be available depending on platform and/or compiler flags |
| #if PLATFORM_NATIVE_STACK_WALKING_SUPPORTED |
| _tracking_level = NMT_detail; |
| #else |
| jio_fprintf(defaultStream::error_stream(), |
| "NMT detail is not supported on this platform. Using NMT summary instead.\n"); |
| _tracking_level = NMT_summary; |
| #endif |
| } 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) { |
| if (!_snapshot->out_of_memory() && start_worker(_snapshot)) { |
| _state = NMT_started; |
| NMT_track_callsite = (_tracking_level == NMT_detail && can_walk_stack()); |
| return; |
| } |
| |
| delete _snapshot; |
| _snapshot = NULL; |
| } |
| |
| // 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 |
| MemRecorder* volatile 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); |
| 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); |
| } |
| |
| // write a record to proper recorder. No lock can be taken from this method |
| // down. |
| void MemTracker::write_tracking_record(address addr, MEMFLAGS flags, |
| size_t size, jint seq, address pc, JavaThread* thread) { |
| |
| MemRecorder* rc = get_thread_recorder(thread); |
| if (rc != NULL) { |
| rc->record(addr, flags, size, seq, 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 |
| #define MAX_RECORDER_THREAD_RATIO 30 |
| #define MAX_RECORDER_PER_THREAD 100 |
| |
| 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; |
| } |
| } |
| { |
| // This method is running at safepoint, with ThreadCritical lock, |
| // it should guarantee that NMT is fully sync-ed. |
| ThreadCritical tc; |
| |
| // We can NOT execute NMT sync-point if there are pending tracking ops. |
| if (_pending_op_count == 0) { |
| SequenceGenerator::reset(); |
| _sync_point_skip_count = 0; |
| |
| // 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; |
| } |
| |
| // see if NMT has too many outstanding recorder instances, it usually |
| // means that worker thread is lagging behind in processing them. |
| if (!AutoShutdownNMT) { |
| _slowdown_calling_thread = (MemRecorder::_instance_count > MAX_RECORDER_THREAD_RATIO * _thread_count); |
| } else { |
| // If auto shutdown is on, enforce MAX_RECORDER_PER_THREAD threshold to prevent OOM |
| if (MemRecorder::_instance_count >= _thread_count * MAX_RECORDER_PER_THREAD) { |
| shutdown(NMT_out_of_memory); |
| } |
| } |
| |
| // 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"); |
| } else { |
| _sync_point_skip_count ++; |
| } |
| } |
| } |
| |
| // 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(MemSnapshot* snapshot) { |
| assert(_worker_thread == NULL && _snapshot != NULL, "Just Check"); |
| _worker_thread = new (std::nothrow) MemTrackWorker(snapshot); |
| if (_worker_thread == NULL) { |
| return false; |
| } else if (_worker_thread->has_error()) { |
| delete _worker_thread; |
| _worker_thread = NULL; |
| 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() { |
| MutexLocker lock(_query_lock); |
| 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; |
| MutexLocker lock(_query_lock); |
| 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; |
| } |
| |
| // Whitebox API for blocking until the current generation of NMT data has been merged |
| bool MemTracker::wbtest_wait_for_data_merge() { |
| // NMT can't be shutdown while we're holding _query_lock |
| MutexLocker lock(_query_lock); |
| assert(_worker_thread != NULL, "Invalid query"); |
| // the generation at query time, so NMT will spin till this generation is processed |
| unsigned long generation_at_query_time = SequenceGenerator::current_generation(); |
| unsigned long current_processing_generation = _processing_generation; |
| // if generation counter overflown |
| bool generation_overflown = (generation_at_query_time < current_processing_generation); |
| long generations_to_wrap = MAX_UNSIGNED_LONG - current_processing_generation; |
| // spin |
| while (!shutdown_in_progress()) { |
| if (!generation_overflown) { |
| if (current_processing_generation > generation_at_query_time) { |
| return true; |
| } |
| } else { |
| assert(generations_to_wrap >= 0, "Sanity check"); |
| long current_generations_to_wrap = MAX_UNSIGNED_LONG - current_processing_generation; |
| assert(current_generations_to_wrap >= 0, "Sanity check"); |
| // to overflow an unsigned long should take long time, so to_wrap check should be sufficient |
| if (current_generations_to_wrap > generations_to_wrap && |
| current_processing_generation > generation_at_query_time) { |
| return true; |
| } |
| } |
| |
| // if worker thread is idle, but generation is not advancing, that means |
| // there is not safepoint to let NMT advance generation, force one. |
| if (_worker_thread_idle) { |
| VM_ForceSafepoint vfs; |
| VMThread::execute(&vfs); |
| } |
| MemSnapshot* snapshot = get_snapshot(); |
| if (snapshot == NULL) { |
| return false; |
| } |
| snapshot->wait(1000); |
| current_processing_generation = _processing_generation; |
| } |
| // We end up here if NMT is shutting down before our data has been merged |
| return false; |
| } |
| |
| // compare memory usage between current snapshot and baseline |
| bool MemTracker::compare_memory_usage(BaselineOutputer& out, size_t unit, bool summary_only) { |
| MutexLocker lock(_query_lock); |
| 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 |
| |
| |
| // Tracker Implementation |
| |
| /* |
| * Create a tracker. |
| * This is a fairly complicated constructor, as it has to make two important decisions: |
| * 1) Does it need to take ThreadCritical lock to write tracking record |
| * 2) Does it need to pre-reserve a sequence number for the tracking record |
| * |
| * The rules to determine if ThreadCritical is needed: |
| * 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 no 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 safepoint-safe states do not stop |
| * for safepoints, ThreadCritical lock should be taken to write |
| * memory records. |
| * 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. |
| * |
| * The memory operations that need pre-reserve sequence numbers: |
| * The memory operations that "release" memory blocks and the |
| * operations can fail, need to pre-reserve sequence number. They |
| * are realloc, uncommit and release. |
| * |
| * The reason for pre-reserve sequence number, is to prevent race condition: |
| * Thread 1 Thread 2 |
| * <release> |
| * <allocate> |
| * <write allocate record> |
| * <write release record> |
| * if Thread 2 happens to obtain the memory address Thread 1 just released, |
| * then NMT can mistakenly report the memory is free. |
| * |
| * Noticeably, free() does not need pre-reserve sequence number, because the call |
| * does not fail, so we can alway write "release" record before the memory is actaully |
| * freed. |
| * |
| * For realloc, uncommit and release, following coding pattern should be used: |
| * |
| * MemTracker::Tracker tkr = MemTracker::get_realloc_tracker(); |
| * ptr = ::realloc(...); |
| * if (ptr == NULL) { |
| * tkr.record(...) |
| * } else { |
| * tkr.discard(); |
| * } |
| * |
| * MemTracker::Tracker tkr = MemTracker::get_virtual_memory_uncommit_tracker(); |
| * if (uncommit(...)) { |
| * tkr.record(...); |
| * } else { |
| * tkr.discard(); |
| * } |
| * |
| * MemTracker::Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); |
| * if (release(...)) { |
| * tkr.record(...); |
| * } else { |
| * tkr.discard(); |
| * } |
| * |
| * Since pre-reserved sequence number is only good for the generation that it is acquired, |
| * when there is pending Tracker that reserved sequence number, NMT sync-point has |
| * to be skipped to prevent from advancing generation. This is done by inc and dec |
| * MemTracker::_pending_op_count, when MemTracker::_pending_op_count > 0, NMT sync-point is skipped. |
| * Not all pre-reservation of sequence number will increment pending op count. For JavaThreads |
| * that honor safepoints, safepoint can not occur during the memory operations, so the |
| * pre-reserved sequence number won't cross the generation boundry. |
| */ |
| MemTracker::Tracker::Tracker(MemoryOperation op, Thread* thr) { |
| _op = NoOp; |
| _seq = 0; |
| if (MemTracker::is_on()) { |
| _java_thread = NULL; |
| _op = op; |
| |
| // figure out if ThreadCritical lock is needed to write this operation |
| // to MemTracker |
| if (MemTracker::is_single_threaded_bootstrap()) { |
| thr = NULL; |
| } else if (thr == 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 |
| thr = ThreadLocalStorage::thread(); |
| } |
| |
| if (thr != NULL) { |
| // Check NMT load |
| MemTracker::check_NMT_load(thr); |
| |
| if (thr->is_Java_thread() && ((JavaThread*)thr)->is_safepoint_visible()) { |
| _java_thread = (JavaThread*)thr; |
| JavaThreadState state = _java_thread->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 |
| _need_thread_critical_lock = |
| SafepointSynchronize::safepoint_safe(_java_thread, state); |
| } else { |
| _need_thread_critical_lock = true; |
| } |
| } else { |
| _need_thread_critical_lock |
| = !MemTracker::is_single_threaded_bootstrap(); |
| } |
| |
| // see if we need to pre-reserve sequence number for this operation |
| if (_op == Realloc || _op == Uncommit || _op == Release) { |
| if (_need_thread_critical_lock) { |
| ThreadCritical tc; |
| MemTracker::inc_pending_op_count(); |
| _seq = SequenceGenerator::next(); |
| } else { |
| // for the threads that honor safepoints, no safepoint can occur |
| // during the lifespan of tracker, so we don't need to increase |
| // pending op count. |
| _seq = SequenceGenerator::next(); |
| } |
| } |
| } |
| } |
| |
| void MemTracker::Tracker::discard() { |
| if (MemTracker::is_on() && _seq != 0) { |
| if (_need_thread_critical_lock) { |
| ThreadCritical tc; |
| MemTracker::dec_pending_op_count(); |
| } |
| _seq = 0; |
| } |
| } |
| |
| |
| void MemTracker::Tracker::record(address old_addr, address new_addr, size_t size, |
| MEMFLAGS flags, address pc) { |
| assert(old_addr != NULL && new_addr != NULL, "Sanity check"); |
| assert(_op == Realloc || _op == NoOp, "Wrong call"); |
| if (MemTracker::is_on() && NMT_CAN_TRACK(flags) && _op != NoOp && !MemTracker::shutdown_in_progress()) { |
| assert(_seq > 0, "Need pre-reserve sequence number"); |
| if (_need_thread_critical_lock) { |
| ThreadCritical tc; |
| // free old address, use pre-reserved sequence number |
| MemTracker::write_tracking_record(old_addr, MemPointerRecord::free_tag(), |
| 0, _seq, pc, _java_thread); |
| MemTracker::write_tracking_record(new_addr, flags | MemPointerRecord::malloc_tag(), |
| size, SequenceGenerator::next(), pc, _java_thread); |
| // decrement MemTracker pending_op_count |
| MemTracker::dec_pending_op_count(); |
| } else { |
| // free old address, use pre-reserved sequence number |
| MemTracker::write_tracking_record(old_addr, MemPointerRecord::free_tag(), |
| 0, _seq, pc, _java_thread); |
| MemTracker::write_tracking_record(new_addr, flags | MemPointerRecord::malloc_tag(), |
| size, SequenceGenerator::next(), pc, _java_thread); |
| } |
| _seq = 0; |
| } |
| } |
| |
| void MemTracker::Tracker::record(address addr, size_t size, MEMFLAGS flags, address pc) { |
| // OOM already? |
| if (addr == NULL) return; |
| |
| if (MemTracker::is_on() && NMT_CAN_TRACK(flags) && _op != NoOp && !MemTracker::shutdown_in_progress()) { |
| bool pre_reserved_seq = (_seq != 0); |
| address pc = CALLER_CALLER_PC; |
| MEMFLAGS orig_flags = flags; |
| |
| // or the tagging flags |
| switch(_op) { |
| case Malloc: |
| flags |= MemPointerRecord::malloc_tag(); |
| break; |
| case Free: |
| flags = MemPointerRecord::free_tag(); |
| break; |
| case Realloc: |
| fatal("Use the other Tracker::record()"); |
| break; |
| case Reserve: |
| case ReserveAndCommit: |
| flags |= MemPointerRecord::virtual_memory_reserve_tag(); |
| break; |
| case Commit: |
| flags = MemPointerRecord::virtual_memory_commit_tag(); |
| break; |
| case Type: |
| flags |= MemPointerRecord::virtual_memory_type_tag(); |
| break; |
| case Uncommit: |
| assert(pre_reserved_seq, "Need pre-reserve sequence number"); |
| flags = MemPointerRecord::virtual_memory_uncommit_tag(); |
| break; |
| case Release: |
| assert(pre_reserved_seq, "Need pre-reserve sequence number"); |
| flags = MemPointerRecord::virtual_memory_release_tag(); |
| break; |
| case ArenaSize: |
| // a bit of hack here, add a small postive offset to arena |
| // address for its size record, so the size record is sorted |
| // right after arena record. |
| flags = MemPointerRecord::arena_size_tag(); |
| addr += sizeof(void*); |
| break; |
| case StackRelease: |
| flags = MemPointerRecord::virtual_memory_release_tag(); |
| break; |
| default: |
| ShouldNotReachHere(); |
| } |
| |
| // write memory tracking record |
| if (_need_thread_critical_lock) { |
| ThreadCritical tc; |
| if (_seq == 0) _seq = SequenceGenerator::next(); |
| MemTracker::write_tracking_record(addr, flags, size, _seq, pc, _java_thread); |
| if (_op == ReserveAndCommit) { |
| MemTracker::write_tracking_record(addr, orig_flags | MemPointerRecord::virtual_memory_commit_tag(), |
| size, SequenceGenerator::next(), pc, _java_thread); |
| } |
| if (pre_reserved_seq) MemTracker::dec_pending_op_count(); |
| } else { |
| if (_seq == 0) _seq = SequenceGenerator::next(); |
| MemTracker::write_tracking_record(addr, flags, size, _seq, pc, _java_thread); |
| if (_op == ReserveAndCommit) { |
| MemTracker::write_tracking_record(addr, orig_flags | MemPointerRecord::virtual_memory_commit_tag(), |
| size, SequenceGenerator::next(), pc, _java_thread); |
| } |
| } |
| _seq = 0; |
| } |
| } |
| |