python中避免死锁的方法介绍

python scott 182℃ 0评论

在python中经常会导致死锁发生,那么如何才能很好的避免死锁的发生呢?下面将会介绍几个python中避免死锁的方法:

本文实例讲述了python避免死锁方法。分享给大家供大家参考。具体分析如下:

当两个或者更多的线程在等待资源的时候就会产生死锁,两个线程相互等待。

在本文实例中 thread1 等待thread2释放block , thread2等待thtead1释放ablock,

避免死锁的原则:

1. 一定要以一个固定的顺序来取得锁,这个列子中,意味着首先要取得alock, 然后再去block

2. 一定要按照与取得锁相反的顺序释放锁,这里,应该先释放block,然后是alock

[cc lang=”python”]

import threading ,time
a = 5
alock = threading.Lock()
b = 5
block = threading.Lock()
def thread1calc():
print “thread1 acquiring lock a”
alock.acquire()
time.sleep(5)
print “thread1 acquiring lock b”
block.acquire()
a+=5
b+=5
print “thread1 releasing both locks”
block.release()
alock.release()
def thread2calc():
print “thread2 acquiring lock b”
block.acquire()
time.sleep(5)
print “thread2 acquiring lock a”
alock.acquire()
time.sleep(5)
a+=10
b+=10
print “thread2 releasing both locks”
block.release()
alock.release()
t = threading.Thread(target = thread1calc)
t.setDaemon(1)
t.start()
t = threading.Thread(target = thread2calc)
t.setDaemon(2)
t.start()
while 1:
time.sleep(300)

[/cc]

输出:

[cc lang=”python”]

thread1 acquiring lock a
thread2 acquiring lock b
thread1 acquiring lock b
thread2 acquiring lock a

[/cc]

python中避免死锁的方法介绍就是这样,欢迎大家参考。。。。

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