Python主进程和分支进程如何共享gc信息

来自https://stackoverflow.com/a/53504673/9191338后:

派生对象被克隆，并在每个进程中最终确定每个对象

fork/forkserver对象在主流程中共享和最终确定

事实似乎是这样:

import os
from multiprocessing import Process
import multiprocessing
multiprocessing.set_start_method('fork', force=True)

class Track:
    def __init__(self):
        print(f'{os.getpid()=} object created in {__name__=}')
    
    def __getstate__(self):
        print(f'{os.getpid()=} object pickled in {__name__=}')
        return {}
    
    def __setstate__(self, state):
        print(f'{os.getpid()=} object unpickled in {__name__=}')
        return self

    def __del__(self):
        print(f'{os.getpid()=} object deleted in {__name__=}')

def f(x):
    print(f'{os.getpid()=} function executed in {__name__=}')

if __name__ == '__main__':

    x = Track()

    for i in range(2):
        print(f'{os.getpid()=} Iteration: {i}, Process object created')
        p = Process(target=f, args=(x,))
        print(f'{os.getpid()=} Iteration: {i}, Process created and started')
        p.start()
        print(f'{os.getpid()=} Iteration: {i}, Process starts to run functions')
        p.join()

输出是:

os.getpid()=30620 object created in __name__='__main__'
os.getpid()=30620 Iteration: 0, Process object created
os.getpid()=30620 Iteration: 0, Process created and started
os.getpid()=30620 Iteration: 0, Process starts to run functions
os.getpid()=30623 function executed in __name__='__main__'
os.getpid()=30620 Iteration: 1, Process object created
os.getpid()=30620 Iteration: 1, Process created and started
os.getpid()=30620 Iteration: 1, Process starts to run functions
os.getpid()=30624 function executed in __name__='__main__'
os.getpid()=30620 object deleted in __name__='__main__'

事实上，该对象仅在主过程中被删除.

我的问题是，这是如何实现的？虽然新流程是从主流程派生出来的，但Forking 之后，新流程本质上是另一个流程，这两个流程如何共享gc信息呢？

此外，gc信息共享是针对每个对象进行，还是仅针对作为子流程参数传递的对象进行？