--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/services/memTracker.cpp Thu Jun 28 17:03:16 2012 -0400
@@ -0,0 +1,617 @@
+/*
+ * 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 "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(Monitor::native, "NMT_queryLock");
+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;)
+debug_only(volatile jint MemTracker::_pending_recorder_count = 0;)
+
+void MemTracker::init_tracking_options(const char* option_line) {
+ _tracking_level = NMT_off;
+ if (strncmp(option_line, "=summary", 8) == 0) {
+ _tracking_level = NMT_summary;
+ } else if (strncmp(option_line, "=detail", 8) == 0) {
+ _tracking_level = NMT_detail;
+ }
+}
+
+// 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;
+ }
+
+ 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);
+ }
+ debug_only(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) {
+ 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) {
+#ifdef ASSERT
+ // cause assertion on stack base. This ensures that threads call
+ // Thread::record_stack_base_and_size() method, which will create
+ // thread native stack records.
+ thread->stack_base();
+#endif
+ // for a JavaThread, if it is running in native state, we need to transition it to
+ // VM state, so it can stop at safepoint. JavaThread running in VM state does not
+ // need lock to write records.
+ if (thread->is_Java_thread() && ((JavaThread*)thread)->is_safepoint_visible()) {
+ if (((JavaThread*)thread)->thread_state() == _thread_in_native) {
+ ThreadInVMfromNative trans((JavaThread*)thread);
+ create_record_in_recorder(addr, flags, size, pc, thread);
+ } else {
+ create_record_in_recorder(addr, flags, size, pc, 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, Thread* thread) {
+ assert(thread == NULL || thread->is_Java_thread(), "wrong thread");
+
+ MemRecorder* rc = get_thread_recorder((JavaThread*)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);
+ }
+ debug_only(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;
+ // walk all JavaThreads to collect recorders
+ SyncThreadRecorderClosure stc;
+ Threads::threads_do(&stc);
+
+ _thread_count = stc.get_thread_count();
+ MemRecorder* pending_recorders = get_pending_recorders();
+
+ {
+ // This method is running at safepoint, with ThreadCritical lock,
+ // it should guarantee that NMT is fully sync-ed.
+ ThreadCritical tc;
+ if (_global_recorder != NULL) {
+ _global_recorder->set_next(pending_recorders);
+ pending_recorders = _global_recorder;
+ _global_recorder = NULL;
+ }
+ SequenceGenerator::reset();
+ // check _worker_thread with lock to avoid racing condition
+ if (_worker_thread != NULL) {
+ _worker_thread->at_sync_point(pending_recorders);
+ }
+ }
+ }
+
+ // now, it is the time to shut whole things off
+ if (_state == NMT_final_shutdown) {
+ _tracking_level = NMT_off;
+
+ // 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;
+ }
+ }
+
+ _state = NMT_shutdown;
+ }
+}
+
+/*
+ * 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
+