Re: [PATCH 5/6] x86, NMI: Allow NMI reason io port (0x61) to be processedon any CPU

[Cyrill Gorcunov]

On 02/28/2011 09:37 PM, Don Zickus wrote:
> On Sun, Feb 27, 2011 at 02:19:11PM +0300, Cyrill Gorcunov wrote:
> > On 02/27/2011 04:01 AM, huang ying wrote:
> > ...
> > > >   Probably we should put question in another fashion, ie in the fasion of
> > > > overall design -- who should be
> > > > responsible for handling external nmis, 1) the cpu which apic is configured
> > > > to observe such nmis or 2) any cpu?
> > > > If we take 1) then no lock is needed and underlied code will report real cpu
> > > > number who observed nmi. If
> > > > we take 2) then lock is needed but we need a big comment in default_do_nmi
> > > > together with probably cpu number
> > > > fixed in serr\iochk printk's.
> > >
> > > I am OK with both solutions.
> > >
> > > Best Regards,
> > > Huang Ying
> >
> > ok, lets see what others think on this thread
>
> I'm trying to figure out how this affects SGI's systems which currently
> enable external NMIs to all cpu's in order to support their nmi button to
> dump cpu stacks on a system hang
> (arch/x86/kernel/apic/x2apic_uv_x.c::uv_nmi_init)
>
> But feel free to post patches addressing your concerns as I am getting a
> little lost in the all the concerns being thrown back and forth.
>
> Cheers,
> Don

  I was planning to do so today but seems out of time at moment (thought I will
try ;), in particular I thought about dropping lock for a while and restore old
behaviour. *BUT* same time to put some big comment explaining why we do this
(so that Ying's work would not be wasted but rather deffered until proper apic
 reconfig implemented).

--
    Cyrill
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