Zack's Kernel News
Zack's Kernel News
Chronicler Zack Brown reports on the latest news, views, dilemmas, and developments within the Linux kernel community.
Incremental Updates to the OOM Killer
Michal Hocko gathered up a few ideas from Mel Gorman and Oleg Nesterov about how to improve the OOM (out-of-memory) killer. This is a bizarre little corner of the kernel whose job is to decide which processes to kill when RAM has become so overused that it threatens to lock up the whole system. The idea is that if it chooses correctly, the OOM killer can restore the system to usability. Of course, if it chooses incorrectly, nobody's happy.
As Michal put it, "The OOM killer currently allows to kill only a single task in a good hope that the task will terminate in a reasonable time and frees up its memory. Such a task (oom victim) will get an access to memory reserves via mark_oom_victim to allow a forward progress should there be a need for additional memory during exit path."
However, a variety of folks, such as Tetsuo Handa, had shown that under some workloads the oom victim could get trapped in the D state and never exit, thus holding onto the extra memory reserves indefinitely.
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