[Devel] Re: namespace acceptance process. bad news

[Eric W. Biederman]

"Denis V. Lunev" <den at sw.ru> writes:

> Daniel Lezcano wrote:
>> Denis V. Lunev wrote:
>>> Hello, All!
>>>
>>> We are completely bite to ground with the current Eric's patchset today
>>> by Dave Miller. flowi tagging considered wrong. The same opinion has
>>> been received from Alexey Kuznetsov :(
>>>
>>> So, it seems that we can't push this approach.
>> 
>> Argh !
>> 
>>>
>>> Daniel, Benjamin, should I merge your code to our git after this news or
>>> we should stop a bit and think? We have talked on OLS that if Dave stop
>>> us with current approach we could try global context as in OpenVz.
>> 
>> IMHO, doing netns switching has no sense now we are so far in the netns
>> implementation.
>> 
>>> I think I'll code this a bit and see a reaction, but we need to have
>>> some agreement here :)
>> 
>> I am more inclined to think about how to handle this problem before
>> doing anything.
>> 
>> Let's try to understand why flowi tagging is considered wrong first.
>> 
>> Alexey seems to disagree with this approach, is it possible to elaborate
>> a little bit ?
>> 
>>
> Here is a quote from Miller:
>
> | I'm not applying this, it's going to have a negative impact on routing
> | performance.
> |
> | It also changes the semantics of the flowi object in a way I very
> | much dislike, in that there is now non-clobberable state in there.
> |
> | Previously only addressing identifying objects were present in the
> | flow, you could use it any context, and there were no pointer
> | dereferencing or object references from this thing.  It was very
> | simple.
> |
> | That is no longer the case after your patch and I don't want us
> | to go down this path.
> |
> | Please find another way to implement this.
>
> flowi marking is a way to deliver the namespace into the routing code,
> as far as I can understand the implementation.

Ok.  Sounds like a reasonable technical objection that we need to look at,
and it is pretty significant.  I need to look at this and sleep on it
before I can address this.

Eric