The Linux kernel's inability to gracefully handle low memory pressure

Re:The Linux kernel's inability to gracefully handle low mem... by simias on Tuesday August 06, 2019 @06:42AM (#20623965)

I haven't toyed with that in a long time (probably about a decade really) but back when I did it was still very difficult to get the OOM to behave the way you wanted. IIRC the scoring is fairly complex and take child processes into account so while it's technically completely deterministic it can still be fairly tricky to anticipate how it's going to work out in practice. And I did know about `oom_adjust`. Often it worked. Sometimes it didn't. Sometimes it would work too well and not kill a process that was clearly using an abnormal amount of memory. Finding the right `oom_adjust` is an art more than a science.

Overall I ended up in the camp "you shouldn't throw passengers out of the plane"[1]. The best way to have the OOM killer behave well is not to have it run at all. If I don't have enough RAM just panic and let me figure out what needs to be done.

[1] https://lwn.net/Articles/104185/

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Re:The Linux kernel's inability to gracefully handle low mem... by SEJeff on Tuesday August 06, 2019 @11:53AM (#20626286)

And the OOM Killer has been rewritten about twice entirely in the past decade. Christoph Lameter (one of my coworkers, who also wrote the SLUB memory allocator) wrote the very first one. Very little if any of his original code is in the current linux OOM Killer.

The current approach does indeed work much better. You can entirely disable the OOM Killer for a given workload with those procfs handles.

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