linux-kernel - Re: [RFC][3/3] Update documentation for virtual address space control

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]

Message-Id: <20080316113200.cc6da618.randy.dunlap@oracle.com>
Date:	Sun, 16 Mar 2008 11:32:00 -0700
From:	Randy Dunlap <randy.dunlap@...cle.com>
To:	Balbir Singh <balbir@...ux.vnet.ibm.com>
Cc:	linux-mm@...ck.org, Hugh Dickins <hugh@...itas.com>,
	Sudhir Kumar <skumar@...ux.vnet.ibm.com>,
	YAMAMOTO Takashi <yamamoto@...inux.co.jp>,
	Paul Menage <menage@...gle.com>, lizf@...fujitsu.com,
	linux-kernel@...r.kernel.org, taka@...inux.co.jp,
	David Rientjes <rientjes@...gle.com>,
	Pavel Emelianov <xemul@...nvz.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Subject: Re: [RFC][3/3] Update documentation for virtual address space
 control

On Sun, 16 Mar 2008 23:00:17 +0530 Balbir Singh wrote:

> This patch adds documentation for virtual address space control.
> 
> Signed-off-by: Balbir Singh <balbir@...ux.vnet.ibm.com>
> ---
> 
>  Documentation/controllers/memory.txt |   26 +++++++++++++++++++++++++-
>  1 file changed, 25 insertions(+), 1 deletion(-)
> 
> diff -puN Documentation/controllers/memory.txt~memory-controller-virtual-address-control-documentation Documentation/controllers/memory.txt
> --- linux-2.6.25-rc5/Documentation/controllers/memory.txt~memory-controller-virtual-address-control-documentation	2008-03-16 22:57:44.000000000 +0530
> +++ linux-2.6.25-rc5-balbir/Documentation/controllers/memory.txt	2008-03-16 22:57:44.000000000 +0530
> @@ -237,7 +237,31 @@ cgroup might have some charge associated
>  tasks have migrated away from it. Such charges are automatically dropped at
>  rmdir() if there are no tasks.
>  
> -5. TODO
> +5. Virtual address space accounting
> +
> +A new resource counter controls the address space expansion of the tasks in
> +the cgroup. Address space control is provided along the same lines as
> +RLIMIT_AS control, which is available via getrlimit(2)/setrlimit(2).
> +The interface for controlling address space is provided through
> +"as_limit_in_bytes". The file is similar to "limit_in_bytes" w.r.t the user

                                                                w.r.t.
  or even spelled out.

> +interface. Please see section 3 for more details on how to use the user
> +interface to get and set values.
> +
> +The "as_usage_in_bytes" file provides information about the total address
> +space usage of the cgroup in bytes.
> +
> +5.1 Advantages of providing this feature
> +
> +1. Control over virtual address space allows for a cgroup to fail gracefully
> +   i.e, via a malloc or mmap failure as compared to OOM kill when no

      i.e.,

> +   pages can be reclaimed

end with period.

> +2. It provides better control over how many pages can be swapped out when
> +   the cgroup goes over it's limit. A badly setup cgroup can cause excessive

                           its (not "it is")

> +   swapping. Providing control over the address space allocations ensures
> +   that the system administrator has control over the total swapping that
> +   can take place.
> +
> +6. TODO
>  
>  1. Add support for accounting huge pages (as a separate controller)
>  2. Make per-cgroup scanner reclaim not-shared pages first
> _

---
~Randy
--
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/