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by tsimionescu
1523 days ago
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The problem is the OOM killer only runs if no pages can be freed. But, on any system, there is some amount of memory that can be swapped out: code pages can be swapped out to their executable/library files on disk. On a system only running a few processes, this is unlikely to matter. But if you have a lot of processes, you may end up in a situation where you can free enough pages by swapping them all out to disk. Now you have no OOMKill, but the next time a process gets to run, you will stall until it is swapped in from disk. Then, the next process will be scheduled, and it too will need to be swapped in, causing another stall, and so on. The machine will probably end up executing, at best, a few instructions per millisecond for hours... |
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