Re: prctl(PR_SET_MM)

[Cyrill Gorcunov <gorcunov@openvz.org>]

On Wed, Feb 20, 2013 at 08:38:01PM +1100, Amnon Shiloh wrote:
> > I personally don't mind if this come become y by default, because it will
> > work for us.
> 
> I don't mind either, to say the least, to have CONFIG_CHECKPOINT_RESTORE
> have a "default y" in "init/Kconfig" - that would solve my problem and make
> me happy, as well as your group and others, but we are told here that Linus
> has a policy vetoing such changes and I don't believe either of us can make
> him change his mind.

That's perfectly fine for all new features :-)

> As such, we must look at other options, such as having the code in
> "kernel/sys.c" out in the open, not enclosed by any #ifdef's altogether
> - surely you would like that!
> 
> > Still I guess if you need to reconstruct Linux process(es)
> > plain prctl extension is not enough, you still need a functionality which
> > is enclosed in config-checkpoint-restore (say /proc/pid/map_files, kcmp),
> > no?
> 
> My process-migration package only reconstructs Linux processes partially:
> as it's a bit different than any classical checkpoint-restore, the critical
> code in "kernel/sys.c" is all I need at the moment (from within
> CONFIG_CHECKPOINT_RESTORE).  I do appreciate that anyone attempting to
> perform complete, classical, checkpoint-restore operations, needs more
> than that.

I see. Thanks for explanation! Thus we need some new config option which would
enable this prctl opcodes (y by default), in turn config-checkpoint-restore
kconfig option need to select this feature if set. Sounds reasonable?