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

[Chen Gong]

ä 2011/10/12 20:51, Don Zickus åé:
> On Wed, Oct 12, 2011 at 10:35:42AM +0800, Chen Gong wrote:
> > ä 2011/10/11 23:24, Don Zickus åé:
> > > +
> > > +		/* sync above data before sending NMI */
> > > +		wmb();
> > > +
> > > +		apic->send_IPI_allbutself(NMI_VECTOR);
> > > +
> > > +		/*
> > > +		 * Don't wait longer than a second if the caller
> > > +		 * didn't ask us to wait.
> > > +		 */
> > > +		timeout = USEC_PER_SEC;
> > > +		while (num_online_cpus()>   1&&   (wait || timeout--))
> > > +			udelay(1);
> >
> > In this patch and next patch, how about using the same logic in commit 74d91e3c6
>
> I guess I don't understand why I would do that.  That commit doesn't seem
> to have a way to break out of the while loop and it does not take into account
> the 'wait' variable the virt folks needed.  The only thing that could be
> usable seems to be the 'touch_nmi_watchdog', but in that case if the other
> cpus haven't hit the NMI yet, I would be happy for other NMI sources to
> trigger to, to help move things along. :-)

Maybe two birds with on stone :-)

> The above code snippet is what is currently there and that seems to work
> well, so I didn't want to change to much when moving from the IRQ path to
> the NMI path.

Fine, if so, I have no objection.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/