show memory usage in memcg.

memcgstat.py

#!/usr/bin/env python3

import argparse
import os
import sys
import time
import signal

def sigint_handler(signalnum, handler):
    sys.exit(0)
    
def show_header():
    print("%s %s %s %s %s %s %s" % ('memory.usage', 'memsw.usage', 'kmem.usage', 'rss', 'rss(huge)', 'cache', 'swap'))

def read_memory_stat_file(hierarchy):
    filename = "/sys/fs/cgroup/memory/%s/memory.stat" % (hierarchy)

    stat = {}
    
    with open(filename, mode='r') as f:
        lines = f.readlines()

        for line in lines:
            data = line.split(' ')
            stat[data[0]] = data[1].strip()

    return stat

def read_cgroup_file(hierarchy, filename):
    fullpath = "/sys/fs/cgroup/memory/%s/%s" % (hierarchy, filename)

    with open(fullpath, mode='r') as f:
        return f.read().strip()
        
def show_mem_stat(args):
    usage = read_cgroup_file(args['mem_hierarchy'], 'memory.usage_in_bytes')
    memsw_usage = read_cgroup_file(args['mem_hierarchy'],'memory.memsw.usage_in_bytes' )
    kmem_usage = read_cgroup_file(args['mem_hierarchy'],'memory.kmem.usage_in_bytes' )

    stat = read_memory_stat_file(args['mem_hierarchy'])
    rss = stat['rss']
    rss_huge = stat['rss_huge']
    cache = stat['cache']
    swap = stat['swap']

    msg = "%s %s %s %s %s %s %s" % (usage, memsw_usage, kmem_usage, rss, rss_huge, cache, swap)

    print(msg)

def hierarchy(pid, subsys):
    filename = "/proc/%d/cgroup" % pid
    keyword = ":%s:" % subsys
    
    with open(filename, mode='r') as f:
        lines = f.readlines()
        for line in lines:
            if line.find(keyword) >= 0:
                arr = line.split(':')
                return  arr[2].strip()

    sys.stderr.write("Couldn't find memory cgroup for pid %d\n" % (pid))
    sys.exit(-1)

def memcg_hierarchy(pid):
    return hierarchy(pid, 'memory')

def parse_argument():
    parser = argparse.ArgumentParser(description = 'vmstat like tool for memory cgroup')
    parser.add_argument('-c', '--count', type=int, default=1, metavar='COUNT', help='count')
    parser.add_argument('-d', '--delay',help='delay second', type=int, metavar='SECOND', default=1)
    parser.add_argument('-p', '--pid', help='pid', metavar='PID', type=int, default=os.getpid())

    args = parser.parse_args()

    vmstat_args = {}
    
    vmstat_args['pid'] = args.pid
    vmstat_args['count'] = args.count
    vmstat_args['delay'] = args.delay

    return vmstat_args

if __name__ == "__main__":
    signal.signal(signal.SIGINT, sigint_handler)
    
    memcg_stat_args = parse_argument()
    
    memcg_stat_args['mem_hierarchy'] = memcg_hierarchy(memcg_stat_args['pid'])

    for i in range(memcg_stat_args['count']):
        if i % 10 == 0:
            show_header()
            
        show_mem_stat(memcg_stat_args)
        time.sleep(memcg_stat_args['delay'])