Limit RAM usage to python program

Question

I\'m trying to limit the RAM usage from a Python program to half so it doesn\'t totally freezes when all the RAM is used, for this I\'m using the following code which is not

Answer 1

I modify the answer of @Ulises CT. Because I think to change too much original function is not so good, so I turn it to a decorator. I hope it helps.

import resource
import platform
import sys

def memory_limit(percentage: float):
    """
    只在linux操作系统起作用
    """
    if platform.system() != "Linux":
        print('Only works on linux!')
        return
    soft, hard = resource.getrlimit(resource.RLIMIT_AS)
    resource.setrlimit(resource.RLIMIT_AS, (get_memory() * 1024 * percentage, hard))

def get_memory():
    with open('/proc/meminfo', 'r') as mem:
        free_memory = 0
        for i in mem:
            sline = i.split()
            if str(sline[0]) in ('MemFree:', 'Buffers:', 'Cached:'):
                free_memory += int(sline[1])
    return free_memory

def memory(percentage=0.8):
    def decorator(function):
        def wrapper(*args, **kwargs):
            memory_limit(percentage)
            try:
                function(*args, **kwargs)
            except MemoryError:
                mem = get_memory() / 1024 /1024
                print('Remain: %.2f GB' % mem)
                sys.stderr.write('\n\nERROR: Memory Exception\n')
                sys.exit(1)
        return wrapper
    return decorator

@memory(percentage=0.8)
def main():
    print('My memory is limited to 80%.')

Answer 2

Ok so I've made some research and found a function to get the memory from Linux systems here: Determine free RAM in Python and I modified it a bit to get just the free memory available and set the maximum memory available as its half.

Code:

def memory_limit():
    soft, hard = resource.getrlimit(resource.RLIMIT_AS)
    resource.setrlimit(resource.RLIMIT_AS, (get_memory() * 1024 / 2, hard))

def get_memory():
    with open('/proc/meminfo', 'r') as mem:
        free_memory = 0
        for i in mem:
            sline = i.split()
            if str(sline[0]) in ('MemFree:', 'Buffers:', 'Cached:'):
                free_memory += int(sline[1])
    return free_memory

if __name__ == '__main__':
    memory_limit() # Limitates maximun memory usage to half
    try:
        main()
    except MemoryError:
        sys.stderr.write('\n\nERROR: Memory Exception\n')
        sys.exit(1)

The line to set it to the half is resource.setrlimit(resource.RLIMIT_AS, (get_memory() * 1024 / 2, hard)) where get_memory() * 1024 / 2 sets it to the half (it's in bytes).

Hope this can help others in future with the same matter! =)

Answer 3

due to https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=34e431b0ae398fc54ea69ff85ec700722c9da773

it is better to use :

if str(sline[0]) == 'MemAvailable:':
            free_memory = int(sline[1])
            break

the answer code provided me with 8 GB of available mem on a machine with 1TB of RAM