memory "leak" in cpyext

gistfile1.txt

running with    "pypy test_memory 10" -> 77  MB retained when using range()
running with "cpython test_memory 10" -> 0.6 MB retained when using range()

test_memory.py

import numpy as np
import psutil
import gc
import os, sys
try:
    import __pypy__
except ImportError:
    __pypy__ = None

def get_process():
    pid = os.getpid()
    return psutil.Process(pid)

_TWO_20 = float(2 ** 20)
def get_memory(process):
    return process.memory_info()[0] / _TWO_20
    

def add_pressure(x):
    if not __pypy__:
        return
    __pypy__.add_memory_pressure(x)


def test_memory(n):
    proc = get_process()
    start = get_memory(proc)
    for i in range(n):
        a = np.arange(100000)
        del a
    for i in range(10):
        add_pressure(1000000)
        gc.collect()
    stop = get_memory(proc)
    print 'arange retaining', stop - start, 'MB'
    start = stop
    for i in range(n):
        a = np.array(range(100000))
        del a
    for i in range(10):
        add_pressure(1000000)
        gc.collect()
    stop = get_memory(proc)
    print 'range retaining', stop - start, 'MB'
    assert stop - start < 100

if __name__ == '__main__':
    if len(sys.argv) > 1:
        n = int(sys.argv[1])
    else:
        n = 1
    test_memory(n)