Messages in this thread Patch in this message | | | From | KOSAKI Motohiro <> | Subject | Re: Memory overcommit | Date | Wed, 28 Oct 2009 11:47:55 +0900 (JST) |
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> 2. I started out running my mlock test program as root (later > switched to use "ulimit -l unlimited" first). But badness() reckons > CAP_SYS_ADMIN or CAP_SYS_RESOURCE is a reason to quarter your points; > and CAP_SYS_RAWIO another reason to quarter your points: so running > as root makes you sixteen times less likely to be killed. Quartering > is anyway debatable, but sixteenthing seems utterly excessive to me. > > I moved the CAP_SYS_RAWIO test in with the others, so it does no > more than quartering; but is quartering appropriate anyway? I did > wonder if I was right to be "subverting" the fine-grained CAPs in > this way, but have since seen unrelated mail from one who knows > better, implying they're something of a fantasy, that su and sudo > are indeed what's used in the real world. Maybe this patch was okay.
I agree quartering is debatable. At least, killing quartering is worth for any user, and it can be push into -stable.
From 27331555366c908a93c2cdd780b77e421869c5af Mon Sep 17 00:00:00 2001 From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Date: Wed, 28 Oct 2009 11:28:39 +0900 Subject: [PATCH] oom: Mitigate suer-user's bonus of oom-score
Currently, badness calculation code of oom contemplate following bonus. - Super-user have quartering oom-score - CAP_SYS_RAWIO process (e.g. database) also have quartering oom-score
The problem is, Super-users have CAP_SYS_RAWIO too. Then, they have sixteenthing bonus. it's obviously too excessive and meaningless.
This patch fixes it.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> --- mm/oom_kill.c | 13 +++++-------- 1 files changed, 5 insertions(+), 8 deletions(-)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index ea2147d..40d323d 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -152,18 +152,15 @@ unsigned long badness(struct task_struct *p, unsigned long uptime) /* * Superuser processes are usually more important, so we make it * less likely that we kill those. - */ - if (has_capability_noaudit(p, CAP_SYS_ADMIN) || - has_capability_noaudit(p, CAP_SYS_RESOURCE)) - points /= 4; - - /* - * We don't want to kill a process with direct hardware access. + * + * Plus, We don't want to kill a process with direct hardware access. * Not only could that mess up the hardware, but usually users * tend to only have this flag set on applications they think * of as important. */ - if (has_capability_noaudit(p, CAP_SYS_RAWIO)) + if (has_capability_noaudit(p, CAP_SYS_ADMIN) || + has_capability_noaudit(p, CAP_SYS_RESOURCE) || + has_capability_noaudit(p, CAP_SYS_RAWIO)) points /= 4; /* -- 1.6.2.5
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