cgroup限定内存

Fri, 06 Jun 2014 14:34:45 +0800

机器配置

ubuntu 12.04

内核版本：3.11.0-20-generic

ulimit的限制效果

ulimit -m 8192 当内存突破8M时，什么事情都没有发生。直到38M都没任何反应。
ulimit -v 65536 python抛出MemoryError

cgroup的限制效果

echo 8388608 > memory.limit_in_bytes

大小不对，cgroup的内存量计算方法和ps/status不一致。因此限制计数需要根据具体情况调整。

内核计数

/proc/[pid]/statm

size       (1) total program size
(same as VmSize in /proc/[pid]/status)
resident   (2) resident set size
(same as VmRSS in /proc/[pid]/status)
share      (3) shared pages (i.e., backed by a file)
text       (4) text (code)
lib        (5) library (unused in Linux 2.6)
data       (6) data + stack
dt         (7) dirty pages (unused in Linux 2.6)

/proc/[pid]/status

statm的size和resident分别乘以pagesize等于VmSize和VmRSS。

利用cgroups隔离多个进程资源消耗的尝试

Wed, 19 Feb 2014 10:14:23 +0800

setup

Add to /etc/fstab.

cgroup                  /sys/fs/cgroup  cgroup  defaults        0       2

Then sudo mount -a.

Change directory to /sys/fs/cgroup/. Use mkdir to create a new group, and initalize it like those.

echo 0-3 >> cpuset.cpus
echo 0 > cpuset.mems

Without those two step, next operator will failure.

echo 0 > memory.swappiness
echo 52428800 > memory.limit_in_bytes

Set memory limit 50M, and forbidden swap.

python test code

import os, sys, time, random, string
def main():
    l = []
    random.seed()
    raw_input()
    for i in xrange(1000000):
        for j in xrange(1000):
            t = list(string.letters)
            random.shuffle(t)
            s = ''.join(t)
            l.append(s)
        time.sleep(0.01)

if __name__ == '__main__': main()

Finally, it triggered OOM.

Cgroup on Shell's Home