checkpoint/restart

[Kip Macy]

>
>     Patch set 6 works like a charm!  If you get stuck on the file handle
>     issue I would be pleased to help out there.  Also note that you should
>     not need to use any ELF/EXEC code at all except for the saved register
>     state once you record the file descriptor state and (if not already
>     recorded) related descriptor mappings, the restore code would be
>     image based.
I hope this isn't a stupid question, but how do I get the inode/dev_t for
binary of the process itself? I'm sure I can find it, but you probably
know off hand.



>
>     If you want to get the kernel hook in for the default signal / module
>     support and add the SIGCKPT and SIGCKPTEXIT signals to sys/signal.h,
>     We can commit that early so people doing ongoing testing of the module
>     do not have to patch their kernels.

I'll see if I can't get that working by tonight. There are couple of open
questions for non-checkpoint-aware apps. What should the checkpoint be
called and where should it be put? Those should probably both be sysctls,
but for the moment I think ckpt.<pid> is a reasonable name, and the
current working directory is a reasonable place.


>
>     FreeBSD-5 has added signal 32, so I recommend we add this to sys/signal.h:
>
> #if __BSD_VISIBLE
> #define SIGTHR          32      /* Thread interrupt (FreeBSD-5 reserved) */
> #define SIGCKPT		33	/* check point and continue */
> #define SIGCKPTEXIT	34	/* check point and exit */
> #endif
>

This works for me.


			-Kip