Find total memory used by Python process and all its children

Question

How can I find the total amount of resident memory used by a Python process and all its forked children?

I know that I can use psutil, for example, to find the percentage of a available physical memory used by the current process like so:

import os
import psutil
current_process = psutil.Process(os.getpid())
mem = current_process.memory_percent()

But I'm looking for the total memory used by a process and its children, if it has any.

Answer 1

You can use the result from psutil.Process.children() (or psutil.Process.get_children() for older psutil versions) to get all child processes and iterate over them.
It could then look like:

import os
import psutil
current_process = psutil.Process(os.getpid())
mem = current_process.memory_percent()
for child in current_process.children(recursive=True):
    mem += child.memory_percent()

This would sum the percentages of memory used by the main process, its children (forks) and any children's children (if you use recursive=True). You can find this function in the current psutil docs or the old docs.

If you use an older version of psutil than 2 you have to use get_children() instead of children().