linux-kernel - Re: [PATCH] badness() dramatically overcounts memory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 05 Feb 2008 15:02:41 -0800
From:	Jeff Davis <linux@...avis.com>
To:	balbir@...ux.vnet.ibm.com
Cc:	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH] badness() dramatically overcounts memory

On Tue, 2008-02-05 at 09:43 +0530, Balbir Singh wrote:
> 1. grep on the kernel source tells me that shared_vm is incremented only in
>    vm_stat_account(), which is a NO-OP if CONFIG_PROC_FS is not defined.

I see, thanks for pointing that out. Is there another way do you think?
Would the penalty be to high to enable vm_stat_account when
CONFIG_PROC_FS is not defined?

Or perhaps my patch would only have an effect when CONFIG_PROC_FS is set
(which is default)?

> 2. How have you tested these patches? One way to do it would be to use the
>    memory controller and set a small limit on the control group. A memory
>    intensive application will soon see an OOM.

I have done a quick test a while back when I first wrote the patch. I
will test more thoroughly now.

> The interesting thing is the use of total_vm and not the RSS which is used as
> the basis by the OOM killer. I need to read/understand the code a bit more.

RSS makes more sense to me as well.

To me, it makes no sense to count shared memory, because killing a
process doesn't free the shared memory.

Regards,
	Jeff Davis

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/