如何使用 python 多处理模块重新启动进程

Question

我正在尝试使用多处理 module 重新启动 python 进程，但是 "AssertionError: cannot start a process twice" 出现了。

我的问题

如何重新启动进程
一旦终止为什么会变成僵尸mod
如何删除僵尸进程

import time
from multiprocessing import Process

def worker ():
    while True:
        print "Inside the worker"
        time.sleep(10)


p1 = Process(target=worker,name="worker")
p1.start()
#p1.join()

time.sleep(3)

p1.terminate()
print "after Termination "
time.sleep(3)


p1.start()

实际上，我正在尝试创建一个进程监视器函数来监视所有进程的内存和 CPU 使用情况。如果达到一定水平我想实时重启

Answer 1

希望对你有所帮助

import time
from multiprocessing import Process

def worker ():
    while True:
        print "Inside the worker"
        time.sleep(10)

def proc_start():
    p_to_start = Process(target=worker,name="worker")
    p_to_start.start()
    return p_to_start


def proc_stop(p_to_stop):
    p_to_stop.terminate()
    print "after Termination "


p = proc_start()
time.sleep(3)
proc_stop(p)
time.sleep(3)

p = proc_start()
print "start gain"
time.sleep(3)
proc_stop(p)

Answer 2

How can I restart the process?

您不能重新启动已终止的进程。您需要实例化一个新进程。

Once its terminated why it is going to zombie mod?

因为在 Unix-y 系统上，父进程需要在内核从进程中清除相应的条目之前读取退出代码 table。

How can I remove the zombie process?

您有多种选择。我在这里引用 docs：

Joining zombie processes

On Unix when a process finishes but has not been joined it becomes a zombie. There should never be very many because each time a new process starts (or active_children() is called) all completed processes which have not yet been joined will be joined. Also calling a finished process’s Process.is_alive will join the process. Even so it is probably good practice to explicitly join all the processes that you start.

Actually I am trying to create a process monitor function to watch the memory and CPU usage of all processes.

你应该看看 psutil 模块。

如果您只是想在内存消耗变高时挂起（而不是终止）进程，您或许可以从我的回答中得到一些启发。

Answer 3

terminate() 进程不允许重新启动进程，但可以使用 kill() 进程并重新启动进程。有效

import time
from multiprocessing import Process

def worker ():
    while True:
        print "Inside the worker"
        time.sleep(10)


p1 = Process(target=worker,name="worker")
p1.start()
#p1.join()

time.sleep(3)

p1.kill()
print "after kill"
time.sleep(3)


p1.start()

如何使用 python 多处理模块重新启动进程

How to restart a process using python multiprocessing module

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