Oracle Linux OOM PGTABLE issue

[alythemonk]

Hey guys,

Noticing since our upgrade to the latest version we be hitting a pgtable oom killer issue on OL which never occurred prior.

I can get the exact error for you BUT its cerianly locking up the entire machine and you have to do a hard reboot of the VM to get things working. Thoughts?

Cheers,

ASD.

[jevolk]

Is this the latest 1.4.9.1 release or main branch version?

[alythemonk]

This would be the latest release 1.4.9.1

[alythemonk]

Here you are, this is what gets plastered into /var/log/messages. The box is completely unresponsive at this point over ssh and you have to hard reset it from a console:

kernel: [ pid ] uid tgid total_vm rss pgtables_bytes swapents oom_score_adj name
kernel: Out of memory: Killed process 2233 (tuwunel) total-vm:8038132kB, anon-rss:7160456kB, file-rss:0kB, shmem-rss:0kB, UID:988 pgtables:14444kB oom_score_adj:0

[jevolk]

Try reducing the cache_capacity_modifier in the config (avoid going too far below 1.0) and also try running with the program option --gc-muzzy=true

[alythemonk]

I added --gc-muzzy=true and set the modifier to 0.9

[dasha-uwu]

@alythemonk any updates?

[alythemonk]

So far so good, not crashes or issues. I think it could be closed. I did just update to 1.5.0 so lets see how it fares.

[jevolk]

We had another user reporting a similar issue. My theory is that the VM host is not coordinating memory pressure with the VM guest, and systemd is overzealous about oom-killing inside the guest.

[alythemonk]

Not sure this is solved. This happened again under 1.5. Prior to 1.4.9.x this was not an issue. I would be extremely surprised if underlying VMWare was that bad .

I am wonder if this is happening after the jemalloc integration? Again when I applied your fix it worked. Wait I wonder if the rpm over wrote the switches you told me to apply. I’ll try them again 2mmorrow.

If overwritten the systemd service file may need a tweak

[alythemonk]

Okay as I thought. The RPM clobbers the changes, you may want to change:

ExecStart=/usr/sbin/tuwunel

to

ExecStart=/usr/sbin/tuwunel --gc-muzzy=true

Thanks.