Re: [PATCH 7/7] uts namespaces: Implement CLONE_NEWUTS flag

[Serge E. Hallyn]

Quoting Andi Kleen (ak@xxxxxxx):
> 
> > But, either the nsproxy is shared between tasks and you need to copy
> > youself a new one as soon as any ns changes
> 
> That would be the case. But it is only shared between tasks where 
> all the name spaces are the same.

Ok, that is how I was thinking.

> > , or it is not shared, and 
> > you don't need  that info at all (just make the change in the nsproxy
> > immediately)
> 
> Don't follow you here.
> 
> Basically the goal is to have a minimum number of nsproxies in the system without
> having to maintain a global hash table. So instead you assume that name space
> changes are infrequent. In the common case of clone without a name space change
> you just share the nsproxy of the parent. If there is a name space change of
> any kind you get a new one.
> 
> This won't get the absolute minimum number of nsproxies, but should be reasonably
> good without too much effort.

Ok.  Then I maintain that the bitmap of changed namespaces seems
unnecessary.  Since you're likely sharing an nsproxy with your parent
process, when you clone a new namespace you just want to immediately get
a new nsproxy pointing to the new namespaces.

Anyway this seems simple enough to just code up.  Simpler than
continuing to talk about it  :)

-serge
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