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authorPaul Mundt <lethal@linux-sh.org>2010-11-15 13:54:00 +0900
committerPaul Mundt <lethal@linux-sh.org>2010-11-15 13:54:00 +0900
commit344ac148442e3223ac1b0e29ef3d3fb73c5ed61a (patch)
tree7b654a74727c57344296768c3a2d7d03b17f37ea /Documentation/ABI/obsolete/proc-pid-oom_adj
parent8ac5ba61cb1a80df407f2cdedb28b28d3b1d84ec (diff)
parent0143832cc96d0bf78486297aad5c8fb2c2ead02a (diff)
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into sh/urgent
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+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.