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| author | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
|---|---|---|
| committer | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
| commit | fcc9d2e5a6c89d22b8b773a64fb4ad21ac318446 (patch) | |
| tree | a57612d1888735a2ec7972891b68c1ac5ec8faea /Documentation/ABI/obsolete/proc-pid-oom_adj | |
| parent | 8dea78da5cee153b8af9c07a2745f6c55057fe12 (diff) | |
Diffstat (limited to 'Documentation/ABI/obsolete/proc-pid-oom_adj')
| -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..9a3cb88ade4 --- /dev/null +++ b/Documentation/ABI/obsolete/proc-pid-oom_adj | |||
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| 1 | What: /proc/<pid>/oom_adj | ||
| 2 | When: August 2012 | ||
| 3 | Why: /proc/<pid>/oom_adj allows userspace to influence the oom killer's | ||
| 4 | badness heuristic used to determine which task to kill when the kernel | ||
| 5 | is out of memory. | ||
| 6 | |||
| 7 | The badness heuristic has since been rewritten since the introduction of | ||
| 8 | this tunable such that its meaning is deprecated. The value was | ||
| 9 | implemented as a bitshift on a score generated by the badness() | ||
| 10 | function that did not have any precise units of measure. With the | ||
| 11 | rewrite, the score is given as a proportion of available memory to the | ||
| 12 | task allocating pages, so using a bitshift which grows the score | ||
| 13 | exponentially is, thus, impossible to tune with fine granularity. | ||
| 14 | |||
| 15 | A much more powerful interface, /proc/<pid>/oom_score_adj, was | ||
| 16 | introduced with the oom killer rewrite that allows users to increase or | ||
| 17 | decrease the badness score linearly. This interface will replace | ||
| 18 | /proc/<pid>/oom_adj. | ||
| 19 | |||
| 20 | A warning will be emitted to the kernel log if an application uses this | ||
| 21 | deprecated interface. After it is printed once, future warnings will be | ||
| 22 | suppressed until the kernel is rebooted. | ||
