Date: Fri, 1 Jun 2007 15:23:34 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: "Serge E. Hallyn" <serue@us.ibm.com>
Cc: menage@google.com, dev@sw.ru, xemul@sw.ru, vatsa@in.ibm.com,
       ebiederm@xmission.com, haveblue@us.ibm.com, svaidy@linux.vnet.ibm.com,
       balbir@in.ibm.com, pj@sgi.com, cpw@sgi.com,
       ckrm-tech@lists.sourceforge.net, linux-kernel@vger.kernel.org,
       containers@lists.osdl.org, mbligh@google.com, rohitseth@google.com,
       devel@openvz.org
Subject: Re: [PATCH 1/2][RFC] containers: improve automatic container naming
Message-Id: <20070601152334.b1452ed5.akpm@linux-foundation.org>
In-Reply-To: <20070601214809.GA20897@sergelap.austin.ibm.com>
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On Fri, 1 Jun 2007 16:48:09 -0500
"Serge E. Hallyn" <serue@us.ibm.com> wrote:

> This compiles and boots, but is not intended for inclusion in -mm (yet),
> just as an RFC for the naming scheme to fix the bug Andrew pointed out.
> 
> Seem ok overall?
> 
> thanks,
> -serge
> 
> >From 8e9b972f7482415777e982d3bc9a0d55cbaf862b Mon Sep 17 00:00:00 2001
> From: Serge E. Hallyn <serue@us.ibm.com>
> Date: Fri, 1 Jun 2007 15:32:15 -0400
> Subject: [PATCH 1/2] containers: improve automatic container naming
> 
> The automatic naming of containers created using container_clone()
> is currently broken (not protected from wraparound) and inconvenient.
> 
> Add a per-container counter for use in naming children of the container.
> Before two unshares in a row by one process, and a third in another,
> would result in
> 
> 	/node1/node2
> 	/node3
> 
> The current scheme should result in
> 
> 	/node1/node1
> 	/node2
> 
> Also, keep a hash table populated with used names, to protect
> against counter wrap-around.
> 
> ...
>
>  include/linux/container.h |    8 +++
>  kernel/container.c        |  116 +++++++++++++++++++++++++++++++++++++++++++--

gad, what's all this stuff?

I think an IDR tree would get you what you're after in much less code. 
Although it means that container IDs would get recycled quickly across a
remove+add.

Be aware that there are IDR enhancements in Greg's driver tree (and hence
in -mm) which are relevant to this application.


> +	if (cont->auto_cnt_set) {

Can we please stop using "cnt" and "cont" to refer to containers?  Let's
use "container", OK?


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