python 不同子进程为何创建出相同的epoll对象

Question

我的目的：不同的进程分别等待不同的socket集合
遇到的问题：我在不同的子进程分别调用 select.epoll()，结果居然返回同一个object！
简单的例子如下：

from multiprocessing import Process,Lock
import time,select

class A(Process):
    def run(self):
        fd = select.epoll()
        print 'A poll_fd:', fd, fd.fileno()
        while 1: time.sleep(3600)

class B(Process):
    def run(self):
        fd = select.epoll()
        print 'B poll_fd:', fd, fd.fileno()
        while 1: time.sleep(3600)

A().start()
B().start()

运行后输出结果如下：

[root@localhost x]# ./test.py 
A poll_fd: <select.epoll object at 0x7f2c4de49150> 4
B poll_fd: <select.epoll object at 0x7f2c4de49150> 4

一个socket可读写，所有子进程都被唤醒了……
有谁遇到过么？请问怎么解决呢？

Answer 1

Just because the id and fileno of two fds are the same, it does not mean that they are two identical objects.

A and B are two different processes. The two fds belong to different process spaces and are not the same.