Re: [PATCH 1/3] x86, reboot: Use NMI instead of REBOOT_VECTOR to stop cpus

Ingo Molnar
2011-10-12T16:35:48Z

* Don Zickus <dzickus@redhat.com> wrote:

> On Wed, Oct 12, 2011 at 09:30:25AM +0200, Ingo Molnar wrote:
> >
> > * Don Zickus <dzickus@redhat.com> wrote:
> >
> > > + if (register_nmi_handler(NMI_LOCAL, smp_stop_nmi_callback,
> > > + NMI_FLAG_FIRST, "smp_stop"))
> > > + return; /* return what? */
> >
> > That comment looks a bit odd.
>
> Yeah, I copied it from the kdump code because it seemed relevant.
> The point was to express the paranoid concern, if we can't register
> the NMI handler for whatever reason, what happens!?. How do we
> explain to anyone we failed to shut down the other cpus?
>
> I can expand the comment to be more specific in the paranoia. I
> just wasn't sure the right way to handle that failure case.

Just add something like:

/* Note: we ignore failures here */

if there's nothing intelligent possible.

Thanks,

Ingo