Re: [PATCH 0/9] OpenVZ kernel based checkpointing/restart

Cedric Le Goater
2008-10-21T09:36:28Z

>> IMHO we should look at Dmitry patchset and merge the external checkpoint
>> code to Oren's patchset in order to checkpoint *one* process and have
>> the process to restart itself. At this point, we can begin to talk about
>> the restart itself, shall we have the kernel to fork the processes to be
>> restarted ? shall we fork from userspace and implement some mechanism to
>> have each processes to restart themselves ? etc...
>>
>
> In both approaches, processes restart themselves, in the sense that a
> process to be restarted eventually calls "do_restart()" (or equivalent).
>
> The only question is how processes are created. Andrew's patch creates
> everything inside the kernel. I would like to still give it a try outside
> the kernel. Everything is ready, except that we need a way to pre-select
> a PID for the new child... we never agreed on that one, did we ?

what do you mean ? like a clone_with_pid() routine ?

> If we go ahead with the kernel-based process creation, it's easy to merge
> it to the current patch-set.

Both solution are valid. Nevertheless, I would choose the solution
sharing existing code and being arch independent.

Now, we can start by duplicating code and see later how we could
share. But for mainline inclusion, I think that code reuse is a
faster path.

C.