How do I make OOM Killer more passive

Question

I am able to compile a program with 1 GiB RAM on a VPS using old 2.6.x kernel. But when I tried to compile it on a VPS with 1.1 GiB RAM and 3.9.x kernel, the compiler always killed by OOM Killer.

How do I make OOM more passive?

Have you tried just turning the stupid thing off? – voretaq7 Jul 10 '13 at 15:10 — voretaq7, Jul 10 '13 at 15:10

score 5 · Accepted Answer · answered Jul 10 '13 at 15:14

You don't change the OOM killer - it's like that for a reason. but what you should do is reduce the memory overcommit. By default this is 50% (see /proc/sys/vm/overcommit_ratio) to handle the case where programs try to claim more memory than they ever need. But if you've got well-written programs which only claim the amount of memory they need (or you're runing JVMs which never do gc because they don't know the system is tight on memory) then the OOM Killer starts harvesting stuff.

btw, vm.overcommit_ratio is used iff vm.overcommit_memory == 2, but default value is 0: http://lxr.free-electrons.com/source/mm/mmap.c#L134 — SaveTheRbtz, Jul 11 '13 at 04:01

SaveTheRbtz · Answer 2 · 2013-07-12T07:53:40.937

-1

If you have enough space on your FS you can add temporary swap space to your VM via:

# fallocate -l 4g /SWAP
# mkswap /SWAP
# swapon /SWAP

But keep in mind that compilation won't be a fast process if your system is aggressively swapping.

edited Jul 12 '13 at 07:53

answered Jul 11 '13 at 04:07

SaveTheRbtz

5,751

Out of curiosity, why map /SWAP to a loopback device? Why not just mkswap /SWAP and swapon /SWAP? – espenfjo Jul 11 '13 at 05:34
3

losetup is useless. Just create an empty file and swapon to make it works. – 比尔盖子 Jul 11 '13 at 07:04
I'm just used to it because it has -e flag that I was using when swapping on external flash drive. Here, yes I guess it's rather useless. – SaveTheRbtz Jul 12 '13 at 07:53
I don't like shouty paths. There's no need to make it shouty. – Tom O'Connor Jul 12 '13 at 08:24

How do I make OOM Killer more passive

2 Answers2