memory management - Determine free RAM in Python

Question

I would like my python script to use all the free RAM available but no more (for efficiency reasons). I can control this by reading in only a limited amount of data but I need to know how much RAM is free at run-time to get this right. It will be run on a variety of Linux systems. Is it possible to determine the free RAM at run-time?

Answer 1

On Linux systems I use this from time to time:

def memory():
    """
    Get node total memory and memory usage
    """
    with open('/proc/meminfo', 'r') as mem:
        ret = {}
        tmp = 0
        for i in mem:
            sline = i.split()
            if str(sline[0]) == 'MemTotal:':
                ret['total'] = int(sline[1])
            elif str(sline[0]) in ('MemFree:', 'Buffers:', 'Cached:'):
                tmp += int(sline[1])
        ret['free'] = tmp
        ret['used'] = int(ret['total']) - int(ret['free'])
    return ret

You can run this when your script starts up. RAM is usually used and freed pretty frequently on a busy system, so you should take that into account before deciding how much RAM to use. Also, most linux systems have a swappiness value of 60. When using up memory, pages that are least frequently used will be swapped out. You may find yourself using SWAP instead of RAM.

Hope this helps.