Re: [PATCH 00/80] Kernel based checkpoint/restart [v18]

Dan Smith wrote:

DL> If the checkpoint is done from the kernel, why the restart
DL> wouldn't be in the kernel too ?

I think thus far we have taken the approach of "if it can be done
reasonably in userspace, then do it there" right?  

Well I am a little lost :)
The tty CR can be "reasonably" done in userspace I think. But it was 
done in the kernel, no ?

Setup of the
network devices is easy to do in userspace, allows more flexibility
from a policy standpoint, and ensures that all existing security
checks are performed. 

Yep, I agree. But you didn't answer the question, what are the network 
resources you plan to checkpoint / restart ?
eg. you let the container to setup your network, will you restore netdev 
statistics ? the mac address ? ipv4 ? ipv6 ?

Is it possible to do a detailed list of network resources you plan to CR 
with the different items you will address from userspace and kernel space ?

Also, migration may be easier if the userspace
bits can call custom hooks allowing for routing changes and other
infrastructure-specific operations.
  

You may have some problems with the connected sockets you will restore 
in this case.

DL> Is there any documentation about the statefile format I can use if
DL> I want to implement myself an userspace CR solution based on this
DL> kernel patchset ?

See linux-cr/include/linux/checkpoint_hdr.h and user-cr/restart.c.
  

Argh ! I was hoping there was something else than the source code :)

Thanks
  -- Daniel

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