Re: [Xenomai-core] [PATCH] let skins select nucleus features

[Philippe Gerum <rpm@xenomai.org>]

Jan Kiszka wrote:
> Philippe Gerum wrote:
> 
>>Jan Kiszka wrote:
>>
>>>Philippe Gerum wrote:
>>>
>>>
>>>>Jan Kiszka wrote:
>>>>
>>>>
>>>>>Hi,
>>>>>
>>>>>this patch aims at avoiding to select unneeded nucleus features if no
>>>>>user is requiring it in the skins. Particularly, it addresses the
>>>>>nucleus registry and the pipes.
>>>>>
>>>>>I have spent no effort on 2.4 yet as I first want to wait for comments.
>>>>>Furthermore, 2.4. is lacking "select", so the feature selection has to
>>>>>remain manually there anyway.
>>>>
>>>>Looks good. Merged, thanks.
>>>>
>>>
>>>
>>>In the same sense, but not that comfortable, here is the a 2.4 variant
>>>of the patch.
>>
>>I don't agree with the logic of this patch. All user-space enabled skins
>>may also run in pure kernel-space in non pervasive mode. A core
>>dependency exists from CONFIG_XENO_OPT_REGISTRY on
>>CONFIG_XENO_OPT_PERVASIVE, and it should be defined explicitely. In any
>>case, maybe it's not worth trying to be too smart with the 2.4
>>configuration system when it comes to dealing with features
>>inter-dependencies, since we really miss the proper support to do that.
>>
> 
> 
> Sorry, doesn't parse for me yet. You that when CONFIG_XENO_OPT_PERVASIVE
> is enabled CONFIG_XENO_OPT_REGISTRY is required (which was not correct,
> see POSIX skin)?

The POSIX skin is an exception, since it implemented its own registry 
support before the native registry was moved as a generic nucleus 
feature; at some point in time, the POSIX registry should be rebased on 
the nucleus support. We must now consider that having 
CONFIG_XENO_OPT_PERVASIVE set requires CONFIG_XENO_OPT_REGISTRY to be 
set too. OTOH, you can have CONFIG_XENO_OPT_REGISTRY set without 
CONFIG_XENO_OPT_PERVASIVE, if you want to run skins in kernel space 
only, whilst still providing registry support for inter-modules requests.

-- 

Philippe.