Java example source code file (threadService.hpp)
The threadService.hpp Java example source code/*
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#ifndef SHARE_VM_SERVICES_THREADSERVICE_HPP
#define SHARE_VM_SERVICES_THREADSERVICE_HPP
#include "classfile/javaClasses.hpp"
#include "runtime/handles.hpp"
#include "runtime/init.hpp"
#include "runtime/jniHandles.hpp"
#include "runtime/objectMonitor.hpp"
#include "runtime/objectMonitor.inline.hpp"
#include "runtime/perfData.hpp"
#include "services/management.hpp"
#include "services/serviceUtil.hpp"
class OopClosure;
class ThreadDumpResult;
class ThreadStackTrace;
class ThreadSnapshot;
class StackFrameInfo;
class ThreadConcurrentLocks;
class DeadlockCycle;
// VM monitoring and management support for the thread and
// synchronization subsystem
//
// Thread contention monitoring is disabled by default.
// When enabled, the VM will begin measuring the accumulated
// elapsed time a thread blocked on synchronization.
//
class ThreadService : public AllStatic {
private:
// These counters could be moved to Threads class
static PerfCounter* _total_threads_count;
static PerfVariable* _live_threads_count;
static PerfVariable* _peak_threads_count;
static PerfVariable* _daemon_threads_count;
// These 2 counters are atomically incremented once the thread is exiting.
// They will be atomically decremented when ThreadService::remove_thread is called.
static volatile int _exiting_threads_count;
static volatile int _exiting_daemon_threads_count;
static bool _thread_monitoring_contention_enabled;
static bool _thread_cpu_time_enabled;
static bool _thread_allocated_memory_enabled;
// Need to keep the list of thread dump result that
// keep references to Method* since thread dump can be
// requested by multiple threads concurrently.
static ThreadDumpResult* _threaddump_list;
public:
static void init();
static void add_thread(JavaThread* thread, bool daemon);
static void remove_thread(JavaThread* thread, bool daemon);
static void current_thread_exiting(JavaThread* jt);
static bool set_thread_monitoring_contention(bool flag);
static bool is_thread_monitoring_contention() { return _thread_monitoring_contention_enabled; }
static bool set_thread_cpu_time_enabled(bool flag);
static bool is_thread_cpu_time_enabled() { return _thread_cpu_time_enabled; }
static bool set_thread_allocated_memory_enabled(bool flag);
static bool is_thread_allocated_memory_enabled() { return _thread_cpu_time_enabled; }
static jlong get_total_thread_count() { return _total_threads_count->get_value(); }
static jlong get_peak_thread_count() { return _peak_threads_count->get_value(); }
static jlong get_live_thread_count() { return _live_threads_count->get_value() - _exiting_threads_count; }
static jlong get_daemon_thread_count() { return _daemon_threads_count->get_value() - _exiting_daemon_threads_count; }
static int exiting_threads_count() { return _exiting_threads_count; }
static int exiting_daemon_threads_count() { return _exiting_daemon_threads_count; }
// Support for thread dump
static void add_thread_dump(ThreadDumpResult* dump);
static void remove_thread_dump(ThreadDumpResult* dump);
static Handle get_current_contended_monitor(JavaThread* thread);
// This function is called by JVM_DumpThreads.
static Handle dump_stack_traces(GrowableArray<instanceHandle>* threads,
int num_threads, TRAPS);
static void reset_peak_thread_count();
static void reset_contention_count_stat(JavaThread* thread);
static void reset_contention_time_stat(JavaThread* thread);
static DeadlockCycle* find_deadlocks_at_safepoint(bool object_monitors_only);
// GC support
static void oops_do(OopClosure* f);
static void metadata_do(void f(Metadata*));
};
// Per-thread Statistics for synchronization
class ThreadStatistics : public CHeapObj<mtInternal> {
private:
// The following contention statistics are only updated by
// the thread owning these statistics when contention occurs.
jlong _contended_enter_count;
elapsedTimer _contended_enter_timer;
jlong _monitor_wait_count;
elapsedTimer _monitor_wait_timer;
jlong _sleep_count;
elapsedTimer _sleep_timer;
// These two reset flags are set to true when another thread
// requests to reset the statistics. The actual statistics
// are reset when the thread contention occurs and attempts
// to update the statistics.
bool _count_pending_reset;
bool _timer_pending_reset;
// Keep accurate times for potentially recursive class operations
int _perf_recursion_counts[6];
elapsedTimer _perf_timers[6];
// utility functions
void check_and_reset_count() {
if (!_count_pending_reset) return;
_contended_enter_count = 0;
_monitor_wait_count = 0;
_sleep_count = 0;
_count_pending_reset = 0;
}
void check_and_reset_timer() {
if (!_timer_pending_reset) return;
_contended_enter_timer.reset();
_monitor_wait_timer.reset();
_sleep_timer.reset();
_timer_pending_reset = 0;
}
public:
ThreadStatistics();
jlong contended_enter_count() { return (_count_pending_reset ? 0 : _contended_enter_count); }
jlong contended_enter_ticks() { return (_timer_pending_reset ? 0 : _contended_enter_timer.active_ticks()); }
jlong monitor_wait_count() { return (_count_pending_reset ? 0 : _monitor_wait_count); }
jlong monitor_wait_ticks() { return (_timer_pending_reset ? 0 : _monitor_wait_timer.active_ticks()); }
jlong sleep_count() { return (_count_pending_reset ? 0 : _sleep_count); }
jlong sleep_ticks() { return (_timer_pending_reset ? 0 : _sleep_timer.active_ticks()); }
void monitor_wait() { check_and_reset_count(); _monitor_wait_count++; }
void monitor_wait_begin() { check_and_reset_timer(); _monitor_wait_timer.start(); }
void monitor_wait_end() { _monitor_wait_timer.stop(); check_and_reset_timer(); }
void thread_sleep() { check_and_reset_count(); _sleep_count++; }
void thread_sleep_begin() { check_and_reset_timer(); _sleep_timer.start(); }
void thread_sleep_end() { _sleep_timer.stop(); check_and_reset_timer(); }
void contended_enter() { check_and_reset_count(); _contended_enter_count++; }
void contended_enter_begin() { check_and_reset_timer(); _contended_enter_timer.start(); }
void contended_enter_end() { _contended_enter_timer.stop(); check_and_reset_timer(); }
void reset_count_stat() { _count_pending_reset = true; }
void reset_time_stat() { _timer_pending_reset = true; }
int* perf_recursion_counts_addr() { return _perf_recursion_counts; }
elapsedTimer* perf_timers_addr() { return _perf_timers; }
};
// Thread snapshot to represent the thread state and statistics
class ThreadSnapshot : public CHeapObj<mtInternal> {
private:
JavaThread* _thread;
oop _threadObj;
java_lang_Thread::ThreadStatus _thread_status;
bool _is_ext_suspended;
bool _is_in_native;
jlong _contended_enter_ticks;
jlong _contended_enter_count;
jlong _monitor_wait_ticks;
jlong _monitor_wait_count;
jlong _sleep_ticks;
jlong _sleep_count;
oop _blocker_object;
oop _blocker_object_owner;
ThreadStackTrace* _stack_trace;
ThreadConcurrentLocks* _concurrent_locks;
ThreadSnapshot* _next;
public:
// Dummy snapshot
ThreadSnapshot() : _thread(NULL), _threadObj(NULL), _stack_trace(NULL), _concurrent_locks(NULL), _next(NULL),
_blocker_object(NULL), _blocker_object_owner(NULL) {};
ThreadSnapshot(JavaThread* thread);
~ThreadSnapshot();
java_lang_Thread::ThreadStatus thread_status() { return _thread_status; }
oop threadObj() const { return _threadObj; }
void set_next(ThreadSnapshot* n) { _next = n; }
bool is_ext_suspended() { return _is_ext_suspended; }
bool is_in_native() { return _is_in_native; }
jlong contended_enter_count() { return _contended_enter_count; }
jlong contended_enter_ticks() { return _contended_enter_ticks; }
jlong monitor_wait_count() { return _monitor_wait_count; }
jlong monitor_wait_ticks() { return _monitor_wait_ticks; }
jlong sleep_count() { return _sleep_count; }
jlong sleep_ticks() { return _sleep_ticks; }
oop blocker_object() { return _blocker_object; }
oop blocker_object_owner() { return _blocker_object_owner; }
ThreadSnapshot* next() const { return _next; }
ThreadStackTrace* get_stack_trace() { return _stack_trace; }
ThreadConcurrentLocks* get_concurrent_locks() { return _concurrent_locks; }
void dump_stack_at_safepoint(int max_depth, bool with_locked_monitors);
void set_concurrent_locks(ThreadConcurrentLocks* l) { _concurrent_locks = l; }
void oops_do(OopClosure* f);
void metadata_do(void f(Metadata*));
};
class ThreadStackTrace : public CHeapObj<mtInternal> {
private:
JavaThread* _thread;
int _depth; // number of stack frames added
bool _with_locked_monitors;
GrowableArray<StackFrameInfo*>* _frames;
GrowableArray<oop>* _jni_locked_monitors;
public:
ThreadStackTrace(JavaThread* thread, bool with_locked_monitors);
~ThreadStackTrace();
JavaThread* thread() { return _thread; }
StackFrameInfo* stack_frame_at(int i) { return _frames->at(i); }
int get_stack_depth() { return _depth; }
void add_stack_frame(javaVFrame* jvf);
void dump_stack_at_safepoint(int max_depth);
Handle allocate_fill_stack_trace_element_array(TRAPS);
void oops_do(OopClosure* f);
void metadata_do(void f(Metadata*));
GrowableArray<oop>* jni_locked_monitors() { return _jni_locked_monitors; }
int num_jni_locked_monitors() { return (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0); }
bool is_owned_monitor_on_stack(oop object);
void add_jni_locked_monitor(oop object) { _jni_locked_monitors->append(object); }
};
// StackFrameInfo for keeping Method* and bci during
// stack walking for later construction of StackTraceElement[]
// Java instances
class StackFrameInfo : public CHeapObj<mtInternal> {
private:
Method* _method;
int _bci;
GrowableArray<oop>* _locked_monitors; // list of object monitors locked by this frame
// We need to save the mirrors in the backtrace to keep the class
// from being unloaded while we still have this stack trace.
oop _class_holder;
public:
StackFrameInfo(javaVFrame* jvf, bool with_locked_monitors);
~StackFrameInfo() {
if (_locked_monitors != NULL) {
delete _locked_monitors;
}
};
Method* method() const { return _method; }
int bci() const { return _bci; }
void oops_do(OopClosure* f);
void metadata_do(void f(Metadata*));
int num_locked_monitors() { return (_locked_monitors != NULL ? _locked_monitors->length() : 0); }
GrowableArray<oop>* locked_monitors() { return _locked_monitors; }
void print_on(outputStream* st) const;
};
class ThreadConcurrentLocks : public CHeapObj<mtInternal> {
private:
GrowableArray<instanceOop>* _owned_locks;
ThreadConcurrentLocks* _next;
JavaThread* _thread;
public:
ThreadConcurrentLocks(JavaThread* thread);
~ThreadConcurrentLocks();
void add_lock(instanceOop o);
void set_next(ThreadConcurrentLocks* n) { _next = n; }
ThreadConcurrentLocks* next() { return _next; }
JavaThread* java_thread() { return _thread; }
GrowableArray<instanceOop>* owned_locks() { return _owned_locks; }
void oops_do(OopClosure* f);
};
class ConcurrentLocksDump : public StackObj {
private:
ThreadConcurrentLocks* _map;
ThreadConcurrentLocks* _last; // Last ThreadConcurrentLocks in the map
bool _retain_map_on_free;
void build_map(GrowableArray<oop>* aos_objects);
void add_lock(JavaThread* thread, instanceOop o);
public:
ConcurrentLocksDump(bool retain_map_on_free) : _map(NULL), _last(NULL), _retain_map_on_free(retain_map_on_free) {};
ConcurrentLocksDump() : _map(NULL), _last(NULL), _retain_map_on_free(false) {};
~ConcurrentLocksDump();
void dump_at_safepoint();
ThreadConcurrentLocks* thread_concurrent_locks(JavaThread* thread);
void print_locks_on(JavaThread* t, outputStream* st);
};
class ThreadDumpResult : public StackObj {
private:
int _num_threads;
int _num_snapshots;
ThreadSnapshot* _snapshots;
ThreadSnapshot* _last;
ThreadDumpResult* _next;
public:
ThreadDumpResult();
ThreadDumpResult(int num_threads);
~ThreadDumpResult();
void add_thread_snapshot(ThreadSnapshot* ts);
void set_next(ThreadDumpResult* next) { _next = next; }
ThreadDumpResult* next() { return _next; }
int num_threads() { return _num_threads; }
int num_snapshots() { return _num_snapshots; }
ThreadSnapshot* snapshots() { return _snapshots; }
void oops_do(OopClosure* f);
void metadata_do(void f(Metadata*));
};
class DeadlockCycle : public CHeapObj<mtInternal> {
private:
bool _is_deadlock;
GrowableArray<JavaThread*>* _threads;
DeadlockCycle* _next;
public:
DeadlockCycle();
~DeadlockCycle();
DeadlockCycle* next() { return _next; }
void set_next(DeadlockCycle* d) { _next = d; }
void add_thread(JavaThread* t) { _threads->append(t); }
void reset() { _is_deadlock = false; _threads->clear(); }
void set_deadlock(bool value) { _is_deadlock = value; }
bool is_deadlock() { return _is_deadlock; }
int num_threads() { return _threads->length(); }
GrowableArray<JavaThread*>* threads() { return _threads; }
void print_on(outputStream* st) const;
};
// Utility class to get list of java threads.
class ThreadsListEnumerator : public StackObj {
private:
GrowableArray<instanceHandle>* _threads_array;
public:
ThreadsListEnumerator(Thread* cur_thread,
bool include_jvmti_agent_threads = false,
bool include_jni_attaching_threads = true);
int num_threads() { return _threads_array->length(); }
instanceHandle get_threadObj(int index) { return _threads_array->at(index); }
};
// abstract utility class to set new thread states, and restore previous after the block exits
class JavaThreadStatusChanger : public StackObj {
private:
java_lang_Thread::ThreadStatus _old_state;
JavaThread* _java_thread;
bool _is_alive;
void save_old_state(JavaThread* java_thread) {
_java_thread = java_thread;
_is_alive = is_alive(java_thread);
if (is_alive()) {
_old_state = java_lang_Thread::get_thread_status(_java_thread->threadObj());
}
}
public:
static void set_thread_status(JavaThread* java_thread,
java_lang_Thread::ThreadStatus state) {
java_lang_Thread::set_thread_status(java_thread->threadObj(), state);
}
void set_thread_status(java_lang_Thread::ThreadStatus state) {
if (is_alive()) {
set_thread_status(_java_thread, state);
}
}
JavaThreadStatusChanger(JavaThread* java_thread,
java_lang_Thread::ThreadStatus state) {
save_old_state(java_thread);
set_thread_status(state);
}
JavaThreadStatusChanger(JavaThread* java_thread) {
save_old_state(java_thread);
}
~JavaThreadStatusChanger() {
set_thread_status(_old_state);
}
static bool is_alive(JavaThread* java_thread) {
return java_thread != NULL && java_thread->threadObj() != NULL;
}
bool is_alive() {
return _is_alive;
}
};
// Change status to waiting on an object (timed or indefinite)
class JavaThreadInObjectWaitState : public JavaThreadStatusChanger {
private:
ThreadStatistics* _stat;
bool _active;
public:
JavaThreadInObjectWaitState(JavaThread *java_thread, bool timed) :
JavaThreadStatusChanger(java_thread,
timed ? java_lang_Thread::IN_OBJECT_WAIT_TIMED : java_lang_Thread::IN_OBJECT_WAIT) {
if (is_alive()) {
_stat = java_thread->get_thread_stat();
_active = ThreadService::is_thread_monitoring_contention();
_stat->monitor_wait();
if (_active) {
_stat->monitor_wait_begin();
}
} else {
_active = false;
}
}
~JavaThreadInObjectWaitState() {
if (_active) {
_stat->monitor_wait_end();
}
}
};
// Change status to parked (timed or indefinite)
class JavaThreadParkedState : public JavaThreadStatusChanger {
private:
ThreadStatistics* _stat;
bool _active;
public:
JavaThreadParkedState(JavaThread *java_thread, bool timed) :
JavaThreadStatusChanger(java_thread,
timed ? java_lang_Thread::PARKED_TIMED : java_lang_Thread::PARKED) {
if (is_alive()) {
_stat = java_thread->get_thread_stat();
_active = ThreadService::is_thread_monitoring_contention();
_stat->monitor_wait();
if (_active) {
_stat->monitor_wait_begin();
}
} else {
_active = false;
}
}
~JavaThreadParkedState() {
if (_active) {
_stat->monitor_wait_end();
}
}
};
// Change status to blocked on (re-)entering a synchronization block
class JavaThreadBlockedOnMonitorEnterState : public JavaThreadStatusChanger {
private:
ThreadStatistics* _stat;
bool _active;
static bool contended_enter_begin(JavaThread *java_thread) {
set_thread_status(java_thread, java_lang_Thread::BLOCKED_ON_MONITOR_ENTER);
ThreadStatistics* stat = java_thread->get_thread_stat();
stat->contended_enter();
bool active = ThreadService::is_thread_monitoring_contention();
if (active) {
stat->contended_enter_begin();
}
return active;
}
public:
// java_thread is waiting thread being blocked on monitor reenter.
// Current thread is the notifying thread which holds the monitor.
static bool wait_reenter_begin(JavaThread *java_thread, ObjectMonitor *obj_m) {
assert((java_thread != NULL), "Java thread should not be null here");
bool active = false;
if (is_alive(java_thread) && ServiceUtil::visible_oop((oop)obj_m->object())) {
active = contended_enter_begin(java_thread);
}
return active;
}
static void wait_reenter_end(JavaThread *java_thread, bool active) {
if (active) {
java_thread->get_thread_stat()->contended_enter_end();
}
set_thread_status(java_thread, java_lang_Thread::RUNNABLE);
}
JavaThreadBlockedOnMonitorEnterState(JavaThread *java_thread, ObjectMonitor *obj_m) :
JavaThreadStatusChanger(java_thread) {
assert((java_thread != NULL), "Java thread should not be null here");
// Change thread status and collect contended enter stats for monitor contended
// enter done for external java world objects and it is contended. All other cases
// like for vm internal objects and for external objects which are not contended
// thread status is not changed and contended enter stat is not collected.
_active = false;
if (is_alive() && ServiceUtil::visible_oop((oop)obj_m->object()) && obj_m->contentions() > 0) {
_stat = java_thread->get_thread_stat();
_active = contended_enter_begin(java_thread);
}
}
~JavaThreadBlockedOnMonitorEnterState() {
if (_active) {
_stat->contended_enter_end();
}
}
};
// Change status to sleeping
class JavaThreadSleepState : public JavaThreadStatusChanger {
private:
ThreadStatistics* _stat;
bool _active;
public:
JavaThreadSleepState(JavaThread *java_thread) :
JavaThreadStatusChanger(java_thread, java_lang_Thread::SLEEPING) {
if (is_alive()) {
_stat = java_thread->get_thread_stat();
_active = ThreadService::is_thread_monitoring_contention();
_stat->thread_sleep();
if (_active) {
_stat->thread_sleep_begin();
}
} else {
_active = false;
}
}
~JavaThreadSleepState() {
if (_active) {
_stat->thread_sleep_end();
}
}
};
#endif // SHARE_VM_SERVICES_THREADSERVICE_HPP
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