import gc
import os

_short_fields = ('VmPeak', 'VmSize', 'VmRSS')

def meminfo(short=True):
    try:
        status_file = file('/proc/%s/status' % os.getpid(), 'rb')
    except IOError:
        return
    try:
        status = status_file.read()
    finally:
        status_file.close()
    for line in status.splitlines():
        for field in _short_fields:
            if line.startswith(field):
                print line
                break

large_set = set(range(4000001))
small_set = set(range(100))

print "Before large_set.difference(small_set):"
meminfo()
print

print "After large_set.difference(small_set):"
diff = large_set.difference(small_set)
gc.collect()
meminfo()