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

[Kirill Korotaev <dev@sw.ru>]

> > 1.
> > flags are neither atomic nor protected with any lock.
>
>
> flags are atomic as they are a machine word.  So they do not
> require a read/modify write so they will either be written
> or not written.  Plus this allows write-sharing of the appropriate
> cache line which is very polite (assuming the line is not shared with
> something else)
Eric I'm familiar with SMP, thanks :)
Why do you write all this if you agreed below that have problems with it?

> > 2. due to 1) you code is buggy. in this respect do_exit() is not serialized with
> > copy_process().
> Yes. I may need a memory barrier in there.  I need to think
> about that a little more.
memory barrier doesn't help. you really need to think about.

> > 3. due to the same 1) reason
> > > +		kill_pspace_info(SIGKILL, (void *)1, tsk->pspace);
> > can miss a task being forked. Bang!!!
>
> Well the only bad thing that can happen is that I get a process that
> can run and observe pid == 1 has exited.  So Bang!! is not too
> painful.
And what about references to pspace->child_reaper which was freed already?

[skipped the flood]

Kirill

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