ubuntu - Large Virtual Memory Size usage -

good day.

i wondering why starting new process using subprocess.popen , asking psutil.process.memory_info() virtual memory size getting more 21 megabytes? (in script started popen prints data read stdin passed main script)

main.py

from subprocess import popen, pipe, stdout import sys, psutil, shlex  popen(shlex.split('python3 ./test.py'), stdin=pipe, stdout=pipe, stderr=stdout) proc:  main_stdin = sys.stdin.read() print('writting main stdin stream:', main_stdin) proc.stdin.write(bytes(main_stdin, 'utf-8')) # "redirect" main's stdin test's stdin  mem_info = psutil.process(proc.pid).memory_info() print('rss:', mem_info.rss/1048576) # bytes megabytes print('vms:', mem_info.vms/1048576)  sub_stdout = proc.communicate()[0].decode('utf-8') print('reading sub stdout: ', sub_stdout) 

test.py

from sys import stdin  print(stdin.read()) 

ubuntu 14.04, python 3.4

thank you!