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Java线程状态以及在JVM中的实现原理

2018-09-21 19:10:08   0  举报

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Java线程状态切换

java

作者其他创作

大纲/内容

park实现

等待队列release lockor monitor

native isInterrupted(false)

获取时间片obtain my timeslice

LockSupport.park()

阻塞状态dosen't releaseany lock or monitor

cpu

ParkEvent * const slp = thread-_SleepEvent ;slp-park(millis);

setPriority()实现

KLT

start

死亡dead

LWP

OSThread* osthread = thread-osthread(); bool interrupted = osthread-interrupted(); if (interrupted && clear_interrupted) { osthread-set_interrupted(false); }

RUNNING运行中

P:进程

synchronized

(re-)entering a synchronization block

把线程放进双向循环等待链表

wait()

运行状态Running

new Thread()

新建new Thread

Thread

锁池lock pool

IN_OBJECT_WAIT

BLOCKED_ON_MONITOR_ENTER

isInterrupted()实现

SLEEPING

void os::yield()

LockSupport.park(long)

Wait Set非线程状态

void Thread::interrupt(Thread* thread)

READY就绪

notifyAll把所有线程放进去

1.Object.wait(long)2.Thread.join(kibg)3.LockSupport.parkNanos(long)4.LockSupport.parkUntil(long)5.Thread.sleep(long)

Parker* p = NULL;p-unpark();

系统调度获取到时间片

Java Thread Priority

Windows Thread Priority

Linux Thread Priority

THREAD_PRIORITY_IDLE

THREAD_PRIORITY_LOWEST

-4

-3

THREAD_PRIORITY_BELOW_NORMAL

-2

-1

THREAD_PRIORITY_NORMAL

THREAD_PRIORITY_ABOVE_NORMAL

THREAD_PRIORITY_HIGHEST

public static boolean interrupted()

可运行状态Runnable

Thread.start()

可运行Runable

1.run()执行结束2.main()执行结束3.抛出异常

public boolean isInterrupted()

等待队列Waiting

o.wait()

被其他线程唤醒notify()或者notifyall()

用户输入结束sleep结束join的线程结束

WAITING等待

TERMINATED结束

RUNNABLE包括就绪和运行中运行中

interrupt()实现

sched_yield();

NEW新建

1.用户输入完成2.sleep时间结束3.join线程结束

BLOCKED堵塞

void Parker::unpark()

1.Thread.yield()2.时间片用完

KLT：内核线程Kernel Thread

拿到对象的锁标记

waitmonitorexit

o.notify()o.notifyall()wait时间到

1.等待用户输入2.Thread.sleep()3.join()

interrupted()实现

RUNNABLE

会释放锁

LWP：轻量级进程（进程中线程）

void os::interrupt(Thread* thread)

初始化状态NEW

1.Object.notify()2.Object.notifyAll()3.LockSupport.unpark(Thread)4.超时时间到

表示jvm层的ThreadStatus

Object.wait(long)

time ！=0

pthread_mutex_unlock(_mutex);

到时间

1.Object.notify()2.Object.notifyAll()3.LockSupport.unpark(Thread)

os::yield();

CPU

OS调度

public void interrupt()

运行中Runing

时间片用完Thread.yield()

sleep实现

结束Terminated

获取到锁

拿到锁标识

等待用户输入Thread.sleept2.join

unpark()实现

锁池的状态

EntryList非线程状态

IN_OBJECT_WAIT_TIMED

native currentThread().isInterrupted(true)

yield()实现

PARKED

1.Object.wait()2.Thread.join()3.LockSupport.park()

1.时间片用完2.Thread.yield()

TERMINATED

Thread.sleep()

1.等待进入synchronized代码块2.等待进入synchronized方法

unpark到时间

osthread-set_interrupted(true);ParkEvent * const slp = thread-_SleepEvent ; if (slp != NULL) slp-unpark() ;((JavaThread*)thread)-parker()-unpark();ParkEvent * ev = thread-_ParkEvent ; if (ev != NULL) ev-unpark() ;

不会释放锁

notify把第一个线程放进等待锁的链表

PARKED_TIMED

os::interrupt(thread);

native interrupt0();

JavaThread* thr = java_lang_Thread::thread(JNIHandles::resolve_non_null(jthread));Thread::interrupt(thr);

void os::PlatformEvent::park()

Thread Scheduler

TIMED_WAITING超时等待

Object.wait()

NEW

unpark