Re: [RFC][PATCH 04/20] pspace: Allow multiple instaces of the processid namespace

From: Kirill Korotaev
Date: Wed Feb 15 2006 - 07:05:01 EST

Hello Eric,

memory barrier doesn't help. you really need to think about.
Except for instances where you need an atomic read/modify/write the
only primitives you have are reads, writes and barriers.

I have all of the correct reads and writes therefore the only thing
that could help are barriers if the logic is otherwise sane.
the problem is that you do read/write for synchronization of other operations (fork/pspace leader die).
i.e. you try to make a serialization, you see? It doesn't work this way.


This exchange seems to have a hostile and not a cooperative tone so
I will finish the investigation and bug fixing elsewhere.
Eric, I think it turned this way because you started pointing to our bugs in VPIDs, while having lots of own and not working code.
I can point you another _really_ disastrous bugs in your IPC and networking virtualization. But discussing bugs is not want I want, you see? I want us to make some solution suatable for all the parties.

And while you have not working solution it is hard to discuss whether it is good or not, whether it is beatutiful or not. It is incomplete and doesn't work. So many statements that one solution is better than another are not valid.

And we are too cycled on PIDs. Why? I think this is the most minor feature which can easily live out of mainstream if needed, while virtualization is the main goal.
I also don't understand why you are eager to introduce new sys calls like pkill(path_to_process), but is trying to use waitpid() for pspace die notifications? Maybe it is simply better to introduce container specific syscalls which should be clean and tidy, instead of messing things up with clone()/waitpid() and so on? The more simple code we have, the better it is for all of us.

If possible keep posting your patches. I would even ask you to add me to CC always. You are doing a really good job and discussion solutions is the only possible way to push something to mainstream I suppose.
I would also be happy to arrange a meeting with the interested parties, since talking eye to eye can be much more productive.

I expect that there might be a few more issues like this. My only
expectation was that the code was complete enough to discuss semantics
and kernel mechanisms for creating a namespaces, and the code has
successfully served that purpose.
To some extent yes.


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