From mboxrd@z Thu Jan  1 00:00:00 1970
From: jamal <hadi@cyberus.ca>
Subject: Re: [PATCH 8/8] net: Implement socketat.
Date: Thu, 23 Sep 2010 08:11:21 -0400
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To: Pavel Emelyanov <xemul@parallels.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>, linux-kernel@vger.kernel.org, Linux Containers <containers@lists.osdl.org>, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Daniel Lezcano <daniel.lezcano@free.fr>, Linus Torvalds <torvalds@linux-foundation.org>, Michael Kerrisk <mtk.manpages@gmail.com>, Ulrich Drepper <drepper@gmail.com>, Al Viro <viro@ZenIV.linux.org.uk>, David Miller <davem@davemloft.net>, "Serge E. Hallyn" <serge@hallyn.com>, Pavel Emelyanov <xemul@openvz.org>, Ben Greear <greearb@candelatech.com>, Matt Helsley <matthltc@us.ibm.com>, Jonathan Corbet <corbet@lwn.net>, Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>, Jan Engelhardt <jengelh@medozas.de>, Patrick McHardy <kaber@trash.net>
List-Id: containers.vger.kernel.org

On Thu, 2010-09-23 at 15:53 +0400, Pavel Emelyanov wrote:

> Why does it matter? You told, that the usage scenario was to
> add routes to container. If I do 2 syscalls instead of 1, is
> it THAT worse?
> 

Anything to do with socket IO that requires namespace awareness
applies for usage; it could be tcp/udp/etc socket. If it doesnt
make any difference performance wise using one scheme vs other
to write/read heavy messages then i dont see an issue and socketat
is redundant.

If i was to pick blindly - I would say whatever approach with
less syscalls is better even if just a "slow" path one time
thing. I could create a scenario which would make it bad
to have more syscalls.

But theres also the simplicity aspect in doing:
fdx = socketat namespace foo
use fdx for read/write/poll into foo without any wrapper code.
Vs
enter foo
fdx = socket ..
read/write fdx
leave foo.

> Just like it used to before the enter.
> 

So if i enter foo, get a fdx, leave foo i can use it in
ns0 as if it was in ns0?

cheers,
jamal