2006-08-01 14:13:31

by Jan-Frode Myklebust

[permalink] [raw]
Subject: [PATCH] oom_adj/oom_score documentation

I was looking for the a way around an OOM-problem, and found
a couple of undocumented new features for tuning the OOM-score
of individual processes. Here's a small documentation patch for
/proc/<pid>/oom_adj and /proc/<pid>/oom_score.

Signed-off-by: Jan-Frode Myklebust <[email protected]>

---

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 99902ae..81bb8ea 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -39,6 +39,8 @@ Table of Contents
2.9 Appletalk
2.10 IPX
2.11 /proc/sys/fs/mqueue - POSIX message queues filesystem
+ 2.12 /proc/<pid>/oom_adj - Adjust the oom-killer score
+ 2.13 /proc/<pid>/oom_score - Display current oom-killer score

------------------------------------------------------------------------------
Preface
@@ -1958,6 +1960,21 @@ a queue must be less or equal then msg_m
maximum message size value (it is every message queue's attribute set during
its creation).

+2.12 /proc/<pid>/oom_adj - Adjust the oom-killer score
+------------------------------------------------------
+
+This file can be used to adjust the score used to select which processes shall
+be killed in an out-of-memory situation. Giving it a high score, increase the
+likelihood of this process being killed by the oom-killer. Valid values are in
+the range [-16:15], plus the special value '-17', which defeat the oom-killer
+altogether.
+
+2.13 /proc/<pid>/oom_score - Display current oom-killer score
+-------------------------------------------------------------
+
+This file can be used to check what the current score used by the oom-killer
+is for any given <pid>. Use it together with /proc/<pid>/oom_adj to tune which
+process will be killed in an out-of-memory situation.

------------------------------------------------------------------------------
Summary


2006-08-01 15:37:35

by Jan-Frode Myklebust

[permalink] [raw]
Subject: Re: [PATCH] oom_adj/oom_score documentation

Got some spelling/language advice from Alan Cox (thanks!), so here's
an updated patch. Hope it reads better now.


Signed-off-by: Jan-Frode Myklebust <[email protected]>

---

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 99902ae..172098a 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -39,6 +39,8 @@ Table of Contents
2.9 Appletalk
2.10 IPX
2.11 /proc/sys/fs/mqueue - POSIX message queues filesystem
+ 2.12 /proc/<pid>/oom_adj - Adjust the oom-killer score
+ 2.13 /proc/<pid>/oom_score - Display current oom-killer score

------------------------------------------------------------------------------
Preface
@@ -1958,6 +1960,22 @@ a queue must be less or equal then msg_m
maximum message size value (it is every message queue's attribute set during
its creation).

+2.12 /proc/<pid>/oom_adj - Adjust the oom-killer score
+------------------------------------------------------
+
+This file can be used to adjust the score used to select which processes
+should be killed in an out-of-memory situation. Giving it a high score will
+increase the likelihood of this process being killed by the oom-killer. Valid
+values are in the range -16 to +15, plus the special value -17, which disables
+oom-killing altogether for this process.
+
+2.13 /proc/<pid>/oom_score - Display current oom-killer score
+-------------------------------------------------------------
+
+------------------------------------------------------------------------------
+This file can be used to check the current score used by the oom-killer is for
+any given <pid>. Use it together with /proc/<pid>/oom_adj to tune which
+process should be killed in an out-of-memory situation.

------------------------------------------------------------------------------
Summary

2006-08-01 16:29:45

by Randy Dunlap

[permalink] [raw]
Subject: Re: [PATCH] oom_adj/oom_score documentation

On Tue, 1 Aug 2006 16:13:08 +0200 Jan-Frode Myklebust wrote:

> I was looking for the a way around an OOM-problem, and found
> a couple of undocumented new features for tuning the OOM-score
> of individual processes. Here's a small documentation patch for
> /proc/<pid>/oom_adj and /proc/<pid>/oom_score.

Thanks, it's needed.

A few comments below.


> Signed-off-by: Jan-Frode Myklebust <[email protected]>
>
> ---
>
> diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
> index 99902ae..81bb8ea 100644
> --- a/Documentation/filesystems/proc.txt
> +++ b/Documentation/filesystems/proc.txt
> @@ -39,6 +39,8 @@ Table of Contents
> 2.9 Appletalk
> 2.10 IPX
> 2.11 /proc/sys/fs/mqueue - POSIX message queues filesystem
> + 2.12 /proc/<pid>/oom_adj - Adjust the oom-killer score
> + 2.13 /proc/<pid>/oom_score - Display current oom-killer score
>
> ------------------------------------------------------------------------------
> Preface
> @@ -1958,6 +1960,21 @@ a queue must be less or equal then msg_m
> maximum message size value (it is every message queue's attribute set during
> its creation).
>
> +2.12 /proc/<pid>/oom_adj - Adjust the oom-killer score
> +------------------------------------------------------
> +
> +This file can be used to adjust the score used to select which processes shall
> +be killed in an out-of-memory situation. Giving it a high score, increase the

Drop the comma. "increases"

> +likelihood of this process being killed by the oom-killer. Valid values are in
> +the range [-16:15], plus the special value '-17', which defeat the oom-killer

"defeats"

> +altogether.
> +
> +2.13 /proc/<pid>/oom_score - Display current oom-killer score
> +-------------------------------------------------------------
> +
> +This file can be used to check what the current score used by the oom-killer
> +is for any given <pid>. Use it together with /proc/<pid>/oom_adj to tune which
> +process will be killed in an out-of-memory situation.
>
> ------------------------------------------------------------------------------
> Summary


---
~Randy