查看“Oom导致进程消失”的源代码

=问题=
<pre>
java哥反映有个进程老是不见了 

[root@prodo-java03 log]# 

cat   messages  | grep oom
Sep 20 05:32:10 prod-hello-java03 kernel: java invoked oom-killer: gfp_mask=0x201da, order=0, oom_score_adj=0
Sep 20 05:32:10 prod-hello-java03 kernel: [<ffffffffbd1ba4e4>] oom_kill_process+0x254/0x3d0
Sep 20 05:32:10 prod-hello-java03 kernel: [<ffffffffbd1b9f8d>] ? oom_unkillable_task+0xcd/0x120
Sep 20 05:32:10 prod-hello-java03 kernel: [ pid ]   uid  tgid total_vm      rss nr_ptes swapents oom_score_adj name
Sep 24 00:01:22 prod-hello-java03 kernel: tuned invoked oom-killer: gfp_mask=0x201da, order=0, oom_score_adj=0
Sep 24 00:01:22 prod-hello-java03 kernel: [<ffffffffbd1ba4e4>] oom_kill_process+0x254/0x3d0
Sep 24 00:01:22 prod-hello-java03 kernel: [<ffffffffbd1b9f8d>] ? oom_unkillable_task+0xcd/0x120
Sep 24 00:01:22 prod-hello-java03 kernel: [ pid ]   uid  tgid total_vm      rss nr_ptes swapents oom_score_adj name
Sep 24 00:01:22 prod-hello-java03 kernel: java invoked oom-killer: gfp_mask=0x201da, order=0, oom_score_adj=0
Sep 24 00:01:22 prod-hello-java03 kernel: [<ffffffffbd1ba4e4>] oom_kill_process+0x254/0x3d0
Sep 24 00:01:22 prod-hello-java03 kernel: [<ffffffffbd1b9f8d>] ? oom_unkillable_task+0xcd/0x120
Sep 24 00:01:22 prod-hello-java03 kernel: [ pid ]   uid  tgid total_vm      rss nr_ptes swapents oom_score_adj name



可见是 java

Sep 24 00:01:22 prod-hello-java03 kernel: Out of memory: Kill process 46473 (java) score 250 or sacrifice child
Sep 24 00:01:22 prod-hello-java03 kernel: Killed process 46473 (java) total-vm:5333504kB, anon-rss:2000260kB, file-rss:0kB, shmem-rss:0kB
Sep 24 00:01:22 prod-hello-java03 kernel: java invoked oom-killer: gfp_mask=0x201da, order=0, oom_score_adj=0
Sep 24 00:01:22 prod-hello-java03 kernel: java cpuset=/ mems_allowed=0
Sep 24 00:01:22 prod-hello-java03 kernel: CPU: 1 PID: 54533 Comm: java Kdump: loaded Not tainted 3.10.0-957.1.3.el7.x86_64 #1
Sep 24 00:01:22 prod-hello-java03 kernel: Hardware name: Xen HVM domU, BIOS 4.2.amazon 08/24/2006
Sep 24 00:01:22 prod-hello-java03 kernel: Call Trace:

##2021 redis oom

Nov 16 02:27:34 prod--db kernel: redis-server invoked oom-killer: gfp_mask=0x10200da, order=0, oom_score_adj=0
Nov 16 02:27:34 prod--db kernel: [<ffffffffc02e271a>] ? virtballoon_oom_notify+0x2a/0x70 [virtio_balloon]
Nov 16 02:27:34 prod--db kernel: [<ffffffff8c7ba524>] oom_kill_process+0x254/0x3d0
Nov 16 02:27:34 prod--db kernel: [<ffffffff8c7b9fcd>] ? oom_unkillable_task+0xcd/0x120
Nov 16 02:27:34 prod--db kernel: [ pid ]   uid  tgid total_vm      rss nr_ptes swapents oom_score_adj name
Nov 24 02:31:


四、总结
这次的故障属于典型的内存不足，导致发生OOM错误的情况。从系统状态和日常的监控以及系统日志的报错等都可发现踪迹，但缺没有引起足够的重视，最终导致死机。
另外，mrtg运行出错，而发送大量垃圾邮件，引起amavisd调用clamscan被卡的问题也使系统不堪负载。
类似的问题，需要针对系统进行监控以分析原因才能采取有效的措施。同时，管理员也不能忽视日常的维护工作，以免出现无可挽救的故障。

※关闭OOM killer机制
在特定情况下，可能我们不希望核心执行OOM killer的工作。例如，排错。
则可以修改/etc/sysctl.conf，增加：
引用
vm.oom-kill = 0

重启或执行sysctl -p即可生效。
若只是临时修改，可执行：
echo 0 > /proc/sys/vm/oom-kill

</pre>

=Linux进程被杀掉oom=
<pre>
grep "Out of memory" /var/log/messages
Nov 14 11:35:56 VM-0-9 kernel: Out of memory: Kill process 27506 (mongod) score 303 or sacrifice child



 egrep -i -r 'killed process' /var/log
匹配到二进制文件 /var/log/journal/d858b31d95a446e491fe879388912c40/system.journal
/var/log/messages:Nov 14 11:35:56 VM-0-9- kernel: Killed process 27506 (mongod), UID 995, total-vm:2779764kB, anon-rss:1173456kB, file-rss:0kB, shmem-rss:0kB

</pre>


=see also=

[http://www.linuxfly.org/post/166/ oom死机处理]

[https://blog.csdn.net/ggh5201314/article/details/105053545  oom killer日志分析]


[https://www.cnblogs.com/duanxz/p/10185946.html  Linux进程被杀掉（OOM killer），查看系统日志 ]


[https://cloud.tencent.com/developer/article/1403389 linux out of memory分析(OOM)]

[[category:shell]] [[category:devops]]

[[category:ops]]