举例讲解Python中的死锁、可重入锁和互斥锁

import threading
import time
class MyThread(threading.Thread):
  def run(self):
    global num
    time.sleep(1)
    if mutex.acquire(1):
      num = num+1
      msg = self.name+' set num to '+str(num)
      print msg
      mutex.acquire()
      mutex.release()
      mutex.release()
num = 0
mutex = threading.Lock()
def test():
  for i in range(5):
    t = MyThread()
    t.start()
if __name__ == '__main__':
  test()

import threading
import time
class MyThread(threading.Thread):
  def do1(self):
    global resA, resB
    if mutexA.acquire():
       msg = self.name+' got resA'
       print msg
       if mutexB.acquire(1):
         msg = self.name+' got resB'
         print msg
         mutexB.release()
       mutexA.release()
  def do2(self):
    global resA, resB
    if mutexB.acquire():
       msg = self.name+' got resB'
       print msg
       if mutexA.acquire(1):
         msg = self.name+' got resA'
         print msg
         mutexA.release()
       mutexB.release()
  def run(self):
    self.do1()
    self.do2()
resA = 0
resB = 0
mutexA = threading.Lock()
mutexB = threading.Lock()
def test():
  for i in range(5):
    t = MyThread()
    t.start()
if __name__ == '__main__':
  test()

import threading
import time
class MyThread(threading.Thread):
  def run(self):
    global num
    time.sleep(1)
    if mutex.acquire(1):
      num = num+1
      msg = self.name+' set num to '+str(num)
      print msg
      mutex.acquire()
      mutex.release()
      mutex.release()
num = 0
mutex = threading.RLock()
def test():
  for i in range(5):
    t = MyThread()
    t.start()
if __name__ == '__main__':
  test()

lock = threading.Lock()
lock.acquire()
dosomething……
lock.release()

[root@361way lock]# cat lock1.py

#!/usr/bin/env python
# coding=utf-8
import threading              # 导入threading模块
import time               # 导入time模块
class mythread(threading.Thread):    # 通过继承创建类
  def __init__(self,threadname):   # 初始化方法
    # 调用父类的初始化方法
    threading.Thread.__init__(self,name = threadname)
  def run(self):             # 重载run方法
    global x         # 使用global表明x为全局变量
    for i in range(3):
      x = x + 1
    time.sleep(5)     # 调用sleep函数，让线程休眠5秒
    print x
tl = []               # 定义列表
for i in range(10):
  t = mythread(str(i))        # 类实例化
  tl.append(t)           # 将类对象添加到列表中
x=0                 # 将x赋值为0
for i in tl:
  i.start() 

[root@361way lock]# python lock1.py

30
30
30
30
30
30
30
30
30
30

[root@361way lock]# cat lock2.py

#!/usr/bin/env python
# coding=utf-8
import threading              # 导入threading模块
import time               # 导入time模块
class mythread(threading.Thread):          # 通过继承创建类
  def __init__(self,threadname):         # 初始化方法
    threading.Thread.__init__(self,name = threadname)
  def run(self):             # 重载run方法
    global x            # 使用global表明x为全局变量
    lock.acquire()           # 调用lock的acquire方法
    for i in range(3):
      x = x + 1
    time.sleep(5)      # 调用sleep函数，让线程休眠5秒
    print x
    lock.release()        # 调用lock的release方法
lock = threading.Lock()        # 类实例化
tl = []             # 定义列表
for i in range(10):
  t = mythread(str(i))      # 类实例化
  tl.append(t)       # 将类对象添加到列表中
x=0            # 将x赋值为0
for i in tl:
  i.start()           # 依次运行线程

[root@361way lock]# python lock2.py

3
6
9
12
15
18
21
24
27
30