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From: Dan Smith <danms@us•ibm.com>
To: hadi@cyberus•ca
Cc: Daniel Lezcano <daniel.lezcano@free•fr>,
	containers@lists•osdl.org,
	Vlad Yasevich <vladislav.yasevich@hp•com>,
	netdev@vger•kernel.org, David Miller <davem@davemloft•net>
Subject: Re: [PATCH] [RFC] C/R: inet4 and inet6 unicast routes (v2)
Date: Mon, 03 May 2010 07:21:02 -0700	[thread overview]
Message-ID: <87y6g1xe0h.fsf@caffeine.danplanet.com> (raw)
In-Reply-To: <1272673614.14499.10.camel@bigi> (jamal's message of "Fri\, 30 Apr 2010 20\:26\:54 -0400")

j> The problem as i see it (with all net structures not just routes -
j> i was equally pessimistic when i saw those other net structure
j> checkpoint/restore changes) is you are faced with a herculean
j> high-maintainance effort...  You have a separate piece of code
j> which populates structures that _you_ maintain for attributes that
j> are defined elsewhere by other people.  Nobody adding a new
j> attribute that is very important to route restoration for example
j> is likely to change your code. Unless you tie the two together (so
j> changing one forces the coder to change the other).  And once
j> people deploy kernels it is hard to change. Historically (for
j> pragmatic reasons) such rich interfaces sit in user space - much
j> easier to update user space.

The benefits of doing what we can in userspace are well-understood and
arguing for doing so where it makes sense is, of course, a good idea.

However, it seems to me that the rtnl interface provides us a
reasonable layer of isolation between us and such changes.  Am I
wrong?  The rtnl messages appear to be rather generic and timeless,
and in most cases have a significant amount of flexibility with
respect to allowing advanced attributes to be ignored (which implies
taking the default).

In many other areas of C/R we're not so lucky and don't have a
well-defined interface for dumping that information out of the
kernel...

-- 
Dan Smith
IBM Linux Technology Center
email: danms@us•ibm.com

  reply	other threads:[~2010-05-03 14:21 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-30 17:00 [PATCH] [RFC] C/R: inet4 and inet6 unicast routes (v2) Dan Smith
2010-04-30 18:19 ` Serge E. Hallyn
2010-04-30 18:25   ` Dan Smith
2010-04-30 18:37     ` Serge E. Hallyn
2010-04-30 20:35 ` Daniel Lezcano
2010-04-30 21:24   ` Dan Smith
     [not found]     ` <87bpd0zl9l.fsf-FLMGYpZoEPULwtHQx/6qkW3U47Q5hpJU@public.gmane.org>
2010-05-01  0:26       ` jamal
2010-05-03 14:21         ` Dan Smith [this message]
2010-05-03 20:34           ` jamal
2010-05-01  2:02     ` Oren Laadan
     [not found]   ` <4BDB3F07.2030900-GANU6spQydw@public.gmane.org>
2010-05-01  1:42     ` Oren Laadan

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