Re: [PATCH] Enhance checkpoint/restart Kconfig options

[Nathan Lynch <ntl-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>]

Dave Hansen <dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org> writes:

> I spent way too much time yesterday trying to figure out why
> my c/r tests weren't running.  It turned out that I didn't
> have any of the namespaces enabled, the sys_unshare() was
> failing, and the debugging didn't explain any of this.
>
> So, to protect the world from repeating my mistakes, let's
> improve the Kconfig options a bit.
>
> 1. Don't say "Enable" in the c/r menu, that's just silly
> 2. move the c/r menu next to the namespaces
> 3. make CHECKPOINT select all of the namespaces
> 4. put a Kconfig 'comment' in explaining how everything
>    got selected.
> 5. Put the namespaces in their own menu
>
> Perhaps I should break this up a bit and we can push some
> of this to the beginning of the series.  Thoughts?
>
> ---
>
>  linux-2.6.git-dave/checkpoint/Kconfig |    7 ++++++-
>  linux-2.6.git-dave/init/Kconfig       |    9 ++++++---
>  2 files changed, 12 insertions(+), 4 deletions(-)
>
> diff -puN checkpoint/Kconfig~cr-kconfig-fixup checkpoint/Kconfig
> --- linux-2.6.git/checkpoint/Kconfig~cr-kconfig-fixup	2009-06-04 11:38:57.000000000 -0700
> +++ linux-2.6.git-dave/checkpoint/Kconfig	2009-06-04 11:38:57.000000000 -0700
> @@ -7,9 +7,14 @@ config DEFERQUEUE
>  	default n
>  
>  config CHECKPOINT
> -	bool "Enable checkpoint/restart (EXPERIMENTAL)"
> +	bool "Checkpoint/restart (EXPERIMENTAL)"
>  	depends on CHECKPOINT_SUPPORT && EXPERIMENTAL
>  	select DEFERQUEUE
> +	select UTS_NS
> +	select IPC_NS
> +	select NET_NS
> +	select PID_NS
> +	select USER_NS

*_NS all depend on NAMESPACES at the very least; some have additional
dependencies.  Selecting a symbol without ensuring its dependencies are
enabled is one way to break a build.

Also - checkpoint is useful without *_NS, no?  Forcing these things on
seems a little user-hostile..