What: /proc/<pid>/oom_adj When: August 2012 Why: /proc/<pid>/oom_adj allows userspace to influence the oom killer's badness heuristic used to determine which task to kill when the kernel is out of memory. The badness heuristic has since been rewritten since the introduction of this tunable such that its meaning is deprecated. The value was implemented as a bitshift on a score generated by the badness() function that did not have any precise units of measure. With the rewrite, the score is given as a proportion of available memory to the task allocating pages, so using a bitshift which grows the score exponentially is, thus, impossible to tune with fine granularity. A much more powerful interface, /proc/<pid>/oom_score_adj, was introduced with the oom killer rewrite that allows users to increase or decrease the badness score linearly. This interface will replace /proc/<pid>/oom_adj. A warning will be emitted to the kernel log if an application uses this deprecated interface. After it is printed once, future warnings will be suppressed until the kernel is rebooted.