2.8. Swapping and Out of Memory Tips

Procedure 2.8. Out of Memory (OOM)

1. The easiest way to change this is to echo the new value to /proc/sys/vm/panic_on_oom.

   ~]# cat /proc/sys/vm/panic_on_oom
   0
   
   ~]# echo 1 > /proc/sys/vm/panic_on_oom
   
   ~]# cat /proc/sys/vm/panic_on_oom
   1
   

   Note

   It is recommended that you make the $RT; kernel panic on OOM. When the system has encountered an OOM state, it is no longer deterministic.
2. It is also possible to prioritize which processes get killed by adjusting the oom_killer score. In /proc/PID/ there are two files named oom_adj and oom_score. Valid scores for oom_adj are in the range -16 to +15. This value is used to calculate the 'badness' of the process using an algorithm that also takes into account how long the process has been running, among other factors. To see the current oom_killer score, view the oom_score for the process. oom_killer will kill processes with the highest scores first.
   This example adjusts the oom_score of a process with a PID of 12465 to make it less likely that oom_killer will kill it.

   ~]# cat /proc/12465/oom_score
   79872
   
   ~]# echo -5 > /proc/12465/oom_adj
   
   ~]# cat /proc/12465/oom_score
   78
   

3. There is also a special value of -17, which disables oom_killer for that process. In the example below, oom_score returns a value of O, indicating that this process would not be killed.

   ~]# cat /proc/12465/oom_score
   78
   
   ~]# echo -17 > /proc/12465/oom_adj
   
   ~]# cat /proc/12465/oom_score
   0