diff options
| author | David Rientjes <rientjes@google.com> | 2010-11-11 14:05:18 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-11-12 07:55:31 -0800 |
| commit | 203f40a5a030ed4048cd40e3bd9ab5df6c5df589 (patch) | |
| tree | 5829b47ddea21cd98901a0f59e655477dc8cdfc9 /Documentation/ABI | |
| parent | 1dce071e18b7264457d17c0dec4c7e430bfaee7d (diff) | |
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: David Rientjes <rientjes@google.com>
Reported-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/obsolete/proc-pid-oom_adj | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/ABI/obsolete/proc-pid-oom_adj b/Documentation/ABI/obsolete/proc-pid-oom_adj new file mode 100644 index 00000000000..cf63f264ce0 --- /dev/null +++ b/Documentation/ABI/obsolete/proc-pid-oom_adj @@ -0,0 +1,22 @@ +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. |