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

Cedric Le Goater
2008-10-20T13:48:47Z

>> I'm afraid that we are forgetting to take the best from both
>> approaches...
>
> I agree with Louis.
>
> I played with Oren's patchset and tryed to port it on x86_64. I was able
> to sys_checkpoint/sys_restart but if you remove the restoring of the
> general registers, the restart still works. I am not an expert on asm,
> but my hypothesis is when we call sys_checkpoint the registers are saved
> on the stack by the syscall and when we restore the memory of the
> process, we restore the stack and the stacked registers are restored
> when exiting the sys_restart. That make me feel there is an important
> gap between external checkpoint and internal checkpoint.
>
> Dmitry's patchset is nice too, but IMO, it goes too far from what we

I think you are talking about Andrey.

C.

> decided to do at the container mini-summit. I think there are a lot of
> design questions to be solved before going further.
>
> 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...