Re: [RFC][PATCH][lxc]: Add --with-usercr configure option

[Sukadev Bhattiprolu <sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>]

Daniel Lezcano [dlezcano-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org] wrote:
> Sukadev Bhattiprolu wrote:
>> Pls let me know if this will work. Will address your other comments
>> and repost entire patchset.
>>
>> ---
>> From: Sukadev Bhattiprolu <sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
>> Date: Wed, 24 Mar 2010 17:26:44 -0700
>> Subject: [PATCH 1/1] Add --with-usercr configure option
>>
>> Add a configure option, --with-usercr=dir which would allow linking
>> with external (i.e USERCR) implementation  of checkpoint/restart.
>>
>> For now, USERCR "publishes" a app-checkpoint.h, checkpoint.o and
>> restart.o files which implement the functions app_checkpoint() and
>> app_restart().
>>
>> Usage:
>> 	$ ./autogen.sh
>>
>> 	$ ./configure --help |grep usercr
>> 	--with-usercr=dir     use the Checkpoint/Restart implementation in 'dir'
>
> Ok, let's call it : --with-cr

Ok, or how about --with-libcr given that it will eventually be a library.

>
>> 	$ ls /home/guest/user-cr/
>> 	app-checkpoint.h    checkpoint.o    restart.o
>>
>> 	$ ./configure --with-usercr=/home/guest/user-cr
>>
>> TODO:
>> 	If names of interfaces in USERCR change, we may want to rename
>> 	the config option too ?
>>
>> 	Can we remove the src/lxc/{checkpoint.o,restart.o} files from
>> 	liblxc.so and lxc-checkpoint/lxc-restart directly with them ?
>> 	That way, the USERCR interfaces/object files don't end up in
>> 	liblxc.so.
>>
>> 	USERCR_CFLAGS are only needed for src/lxc/{checkpoint.c,restart.c}
>> 	but not sure if there is an easy way to define autoconf CFLAGS
>> 	just for those two files.
>
> Hum, no. It would be preferable to integrate them in lxc for now (as  
> experimental code) and later create a glue between lxc and usercr, so  
> usercr interfaces would be callable as a plugin of lxc.
>
> The --with-cr will remains but specifying a CR library. The lxc  
> checkpoint and restart code will then dlopen this library and use the  
> checkpoint / restart functions of this library.
>
> If no library is specified, the lxc-checkpoint / lxc-restart will return  
> ENOSYS.
>
> That will ensure the CR specific code stays in a separate library and  
> will keep things opened to take into account other CR solutions like 
> blcr.
>
> But until we reach this point, we should integrate everything hardcoded  
> in the lxc library in order to let the plugin API drawing to appear in  
> the integration big picture.

Ok. Sounds good. I will leave the USERCR interfaces in liblxc.so for now.