Mercurial > hg > graal-jvmci-8
diff src/share/vm/services/memTracker.cpp @ 20360:833b0f92429a
8046598: Scalable Native memory tracking development
Summary: Enhance scalability of native memory tracking
Reviewed-by: coleenp, ctornqvi, gtriantafill
author | zgu |
---|---|
date | Wed, 27 Aug 2014 08:19:12 -0400 |
parents | ce8f6bb717c9 |
children | 36c9011aaead |
line wrap: on
line diff
--- a/src/share/vm/services/memTracker.cpp Wed Aug 27 09:36:55 2014 +0200 +++ b/src/share/vm/services/memTracker.cpp Wed Aug 27 08:19:12 2014 -0400 @@ -1,5 +1,5 @@ /* - * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2012, 2014, 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 @@ -23,862 +23,308 @@ */ #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 "runtime/mutex.hpp" +#include "services/memBaseline.hpp" #include "services/memReporter.hpp" +#include "services/mallocTracker.inline.hpp" #include "services/memTracker.hpp" -#include "utilities/decoder.hpp" #include "utilities/defaultStream.hpp" -#include "utilities/globalDefinitions.hpp" -bool NMT_track_callsite = false; +#ifdef SOLARIS + volatile bool NMT_stack_walkable = false; +#else + volatile bool NMT_stack_walkable = true; +#endif -// 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 ++; -} +volatile NMT_TrackingLevel MemTracker::_tracking_level = NMT_unknown; +NMT_TrackingLevel MemTracker::_cmdline_tracking_level = NMT_unknown; + +NativeCallStack emptyStack(0, false); + +MemBaseline MemTracker::_baseline; +Mutex* MemTracker::_query_lock = NULL; +bool MemTracker::_is_nmt_env_valid = true; -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 +NMT_TrackingLevel MemTracker::init_tracking_level() { + NMT_TrackingLevel level = NMT_off; + char buf[64]; + char nmt_option[64]; + jio_snprintf(buf, sizeof(buf), "NMT_LEVEL_%d", os::current_process_id()); + if (os::getenv(buf, nmt_option, sizeof(nmt_option))) { + if (strcmp(nmt_option, "summary") == 0) { + level = NMT_summary; + } else if (strcmp(nmt_option, "detail") == 0) { #if PLATFORM_NATIVE_STACK_WALKING_SUPPORTED - _tracking_level = NMT_detail; + 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; + level = NMT_summary; +#endif // PLATFORM_NATIVE_STACK_WALKING_SUPPORTED + } else if (strcmp(nmt_option, "off") != 0) { + // The option value is invalid + _is_nmt_env_valid = false; } - _query_lock = new (std::nothrow) Mutex(Monitor::max_nonleaf, "NMT_queryLock"); - if (_query_lock == NULL) { - shutdown(NMT_out_of_memory); - return; - } + // Remove the environment variable to avoid leaking to child processes + os::unsetenv(buf); + } - debug_only(_main_thread_tid = os::current_thread_id();) - _state = NMT_bootstrapping_single_thread; - NMT_track_callsite = (_tracking_level == NMT_detail && can_walk_stack()); + if (!MallocTracker::initialize(level) || + !VirtualMemoryTracker::initialize(level)) { + level = NMT_off; } + return level; } -// 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; +void MemTracker::init() { + if (tracking_level() >= NMT_summary) { + _query_lock = new (std::nothrow) Mutex(Monitor::max_nonleaf, "NMT_queryLock"); + // Already OOM. It is unlikely, but still have to handle it. + if (_query_lock == NULL) { + shutdown(); } } } -// 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; +bool MemTracker::check_launcher_nmt_support(const char* value) { + if (strcmp(value, "=detail") == 0) { +#if !PLATFORM_NATIVE_STACK_WALKING_SUPPORTED + jio_fprintf(defaultStream::error_stream(), + "NMT detail is not supported on this platform. Using NMT summary instead.\n"); + if (MemTracker::tracking_level() != NMT_summary) { + return false; + } +#else + if (MemTracker::tracking_level() != NMT_detail) { + return false; + } +#endif + } else if (strcmp(value, "=summary") == 0) { + if (MemTracker::tracking_level() != NMT_summary) { + return false; + } + } else if (strcmp(value, "=off") == 0) { + if (MemTracker::tracking_level() != NMT_off) { + return false; + } + } else { + _is_nmt_env_valid = false; + } + + return true; +} + +bool MemTracker::verify_nmt_option() { + return _is_nmt_env_valid; +} + +void* MemTracker::malloc_base(void* memblock) { + return MallocTracker::get_base(memblock); +} + +void Tracker::record(address addr, size_t size) { + if (MemTracker::tracking_level() < NMT_summary) return; + switch(_type) { + case uncommit: + VirtualMemoryTracker::remove_uncommitted_region(addr, size); + break; + case release: + VirtualMemoryTracker::remove_released_region(addr, size); + break; + default: + ShouldNotReachHere(); } } -/* - * 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; + +// Shutdown can only be issued via JCmd, and NMT JCmd is serialized +// by lock +void MemTracker::shutdown() { + // We can only shutdown NMT to minimal tracking level if it is + // ever on. + if (tracking_level () > NMT_minimal) { + transition_to(NMT_minimal); + } +} + +bool MemTracker::transition_to(NMT_TrackingLevel level) { + NMT_TrackingLevel current_level = tracking_level(); - MemRecorder* rc; - if (thread == NULL) { - rc = _global_recorder; + if (current_level == level) { + return true; + } else if (current_level > level) { + // Downgrade tracking level, we want to lower the tracking + // level first + _tracking_level = level; + // Make _tracking_level visible immediately. + OrderAccess::fence(); + VirtualMemoryTracker::transition(current_level, level); + MallocTracker::transition(current_level, level); + + if (level == NMT_minimal) _baseline.reset(); } else { - rc = thread->get_recorder(); - } + VirtualMemoryTracker::transition(current_level, level); + MallocTracker::transition(current_level, level); - if (rc != NULL && rc->is_full()) { - enqueue_pending_recorder(rc); - rc = NULL; + _tracking_level = level; + // Make _tracking_level visible immediately. + OrderAccess::fence(); } - if (rc == NULL) { - rc = get_new_or_pooled_instance(); - if (thread == NULL) { - _global_recorder = rc; - } else { - thread->set_recorder(rc); - } - } - return rc; + return true; } -/* - * 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; +void MemTracker::final_report(outputStream* output) { + assert(output != NULL, "No output stream"); + if (tracking_level() >= NMT_summary) { + MallocMemorySnapshot* malloc_memory_snapshot = + MallocMemorySummary::as_snapshot(); + malloc_memory_snapshot->make_adjustment(); + + VirtualMemorySnapshot* virtual_memory_snapshot = + VirtualMemorySummary::as_snapshot(); + + MemSummaryReporter rptr(malloc_memory_snapshot, + virtual_memory_snapshot, output); + rptr.report(); + // shutdown NMT, the data no longer accurate + shutdown(); } } -/* - * 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; -} +// This is a walker to gather malloc site hashtable statistics, +// the result is used for tuning. +class StatisticsWalker : public MallocSiteWalker { + private: + enum Threshold { + // aggregates statistics over this threshold into one + // line item. + report_threshold = 20 + }; -/* - * 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; - } + private: + // Number of allocation sites that have all memory freed + int _empty_entries; + // Total number of allocation sites, include empty sites + int _total_entries; + // Number of captured call stack distribution + int _stack_depth_distribution[NMT_TrackingStackDepth]; + // Hash distribution + int _hash_distribution[report_threshold]; + // Number of hash buckets that have entries over the threshold + int _bucket_over_threshold; - 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) { + // The hash bucket that walker is currently walking + int _current_hash_bucket; + // The length of current hash bucket + int _current_bucket_length; + // Number of hash buckets that are not empty + int _used_buckets; + // Longest hash bucket length + int _longest_bucket_length; - MemRecorder* rc = get_thread_recorder(thread); - if (rc != NULL) { - rc->record(addr, flags, size, seq, pc); + public: + StatisticsWalker() : _empty_entries(0), _total_entries(0) { + int index = 0; + for (index = 0; index < NMT_TrackingStackDepth; index ++) { + _stack_depth_distribution[index] = 0; } -} - -/** - * 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; + for (index = 0; index < report_threshold; index ++) { + _hash_distribution[index] = 0; + } + _bucket_over_threshold = 0; + _longest_bucket_length = 0; + _current_hash_bucket = -1; + _current_bucket_length = 0; + _used_buckets = 0; } - 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); + virtual bool at(const MallocSite* e) { + if (e->size() == 0) _empty_entries ++; + _total_entries ++; + + // stack depth distrubution + int frames = e->call_stack()->frames(); + _stack_depth_distribution[frames - 1] ++; + + // hash distribution + int hash_bucket = e->hash() % MallocSiteTable::hash_buckets(); + if (_current_hash_bucket == -1) { + _current_hash_bucket = hash_bucket; + _current_bucket_length = 1; + } else if (_current_hash_bucket == hash_bucket) { + _current_bucket_length ++; + } else { + record_bucket_length(_current_bucket_length); + _current_hash_bucket = hash_bucket; + _current_bucket_length = 1; + } + return true; } - 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"); + // walk completed + void completed() { + record_bucket_length(_current_bucket_length); + } - // 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; + void report_statistics(outputStream* out) { + int index; + out->print_cr("Malloc allocation site table:"); + out->print_cr("\tTotal entries: %d", _total_entries); + out->print_cr("\tEmpty entries: %d (%2.2f%%)", _empty_entries, ((float)_empty_entries * 100) / _total_entries); + out->print_cr(" "); + out->print_cr("Hash distribution:"); + if (_used_buckets < MallocSiteTable::hash_buckets()) { + out->print_cr("empty bucket: %d", (MallocSiteTable::hash_buckets() - _used_buckets)); + } + for (index = 0; index < report_threshold; index ++) { + if (_hash_distribution[index] != 0) { + if (index == 0) { + out->print_cr(" %d entry: %d", 1, _hash_distribution[0]); + } else if (index < 9) { // single digit + out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]); + } else { + out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]); + } } } - { - // 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 ++; + if (_bucket_over_threshold > 0) { + out->print_cr(" >%d entries: %d", report_threshold, _bucket_over_threshold); + } + out->print_cr("most entries: %d", _longest_bucket_length); + out->print_cr(" "); + out->print_cr("Call stack depth distribution:"); + for (index = 0; index < NMT_TrackingStackDepth; index ++) { + if (_stack_depth_distribution[index] > 0) { + out->print_cr("\t%d: %d", index + 1, _stack_depth_distribution[index]); } } } - // 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; + private: + void record_bucket_length(int length) { + _used_buckets ++; + if (length <= report_threshold) { + _hash_distribution[length - 1] ++; + } else { + _bucket_over_threshold ++; } - } -} - -/* - * 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; + _longest_bucket_length = MAX2(_longest_bucket_length, length); } - 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 +void MemTracker::tuning_statistics(outputStream* out) { + // NMT statistics + StatisticsWalker walker; + MallocSiteTable::walk_malloc_site(&walker); + walker.completed(); -/* - * 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(); - } - } - } + out->print_cr("Native Memory Tracking Statistics:"); + out->print_cr("Malloc allocation site table size: %d", MallocSiteTable::hash_buckets()); + out->print_cr(" Tracking stack depth: %d", NMT_TrackingStackDepth); + NOT_PRODUCT(out->print_cr("Peak concurrent access: %d", MallocSiteTable::access_peak_count());) + out->print_cr(" "); + walker.report_statistics(out); } -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) { - 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) { - 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; - } -} -