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Commit 203f40a5 authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds
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oom: document obsolete oom_adj tunable 



/proc/pid/oom_adj was deprecated in August 2010 with the introduction of
the new oom killer heuristic.

This patch copies the Documentation/feature-removal-schedule.txt entry for
this tunable to the Documentation/ABI/obsolete directory so nobody misses
it.

Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Reported-by: default avatarAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1dce071e

Documentation/ABI/obsolete/proc-pid-oom_adj

0 → 100644
+22 −0
Original line number Diff line number Diff line 
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.