diff options
| author | David Rientjes <rientjes@google.com> | 2010-09-22 22:04:52 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-09-23 02:22:38 +0200 |
| commit | f19e8aa11afa24036c6273428da51949b5acf30c (patch) | |
| tree | e768541c3b83ffe488119f77ef178cdf97f9bece /mm | |
| parent | Prevent freeing uninitialized pointer in compat_do_readv_writev (diff) | |
| download | linux-f19e8aa11afa24036c6273428da51949b5acf30c.tar.xz linux-f19e8aa11afa24036c6273428da51949b5acf30c.zip | |
oom: always return a badness score of non-zero for eligible tasks
A task's badness score is roughly a proportion of its rss and swap
compared to the system's capacity. The scale ranges from 0 to 1000 with
the highest score chosen for kill. Thus, this scale operates on a
resolution of 0.1% of RAM + swap. Admin tasks are also given a 3% bonus,
so the badness score of an admin task using 3% of memory, for example,
would still be 0.
It's possible that an exceptionally large number of tasks will combine to
exhaust all resources but never have a single task that uses more than
0.1% of RAM and swap (or 3.0% for admin tasks).
This patch ensures that the badness score of any eligible task is never 0
so the machine doesn't unnecessarily panic because it cannot find a task
to kill.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/oom_kill.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index fc81cb22869e..859250c7dc06 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -208,8 +208,13 @@ unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem, */ points += p->signal->oom_score_adj; - if (points < 0) - return 0; + /* + * Never return 0 for an eligible task that may be killed since it's + * possible that no single user task uses more than 0.1% of memory and + * no single admin tasks uses more than 3.0%. + */ + if (points <= 0) + return 1; return (points < 1000) ? points : 1000; } |