[RFC][PATCH 1/4] checkpoint-restart: general infrastructure

Dave Hansen dave at linux.vnet.ibm.com
Fri Aug 8 15:26:51 PDT 2008

On Sat, 2008-08-09 at 00:13 +0200, Arnd Bergmann wrote:
> > I have to wonder if this is just a symptom of us trying to do this the
> > wrong way.  We're trying to talk the kernel into writing internal gunk
> > into a FD.  You're right, it is like a splice where one end of the pipe
> > is in the kernel.
> > 
> > Any thoughts on a better way to do this?  
> Maybe you can invert the logic and let the new syscalls create a file
> descriptor, and then have user space read or splice the checkpoint
> data from it, and restore it by writing to the file descriptor.
> It's probably easy to do using anon_inode_getfd() and would solve this
> problem, but at the same time make checkpointing the current thread
> hard if not impossible.

Yeah, it does seem kinda backwards.  But, instead of even having to
worry about the anon_inode stuff, why don't we just put it in a fs like
everything else?  checkpointfs!

I'm also really not convinced that putting the entire checkpoint in one
glob is really the solution, either.  I mean, is system call overhead
really a problem here?

-- Dave

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