Date: Fri, 1 Jun 2007 17:38:55 -0500
From: "Serge E. Hallyn" <serue@us.ibm.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "Serge E. Hallyn" <serue@us.ibm.com>, 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
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References: <20070601214809.GA20897@sergelap.austin.ibm.com> <20070601152334.b1452ed5.akpm@linux-foundation.org>
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Quoting Andrew Morton (akpm@linux-foundation.org):
> 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?

The sound of me starting over.

> I think an IDR tree would get you what you're after in much less code. 

Ok, will look at that.  Thanks for the tip!

> 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?

Ok.

thanks,
-serge
-
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