linux-kernel - Re: [PATCH -v2 7/7] x86, NMI, Remove do_nmi

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Message-ID: <20100930040432.GD26290@redhat.com>
Date:	Thu, 30 Sep 2010 00:04:32 -0400
From:	Don Zickus <dzickus@...hat.com>
To:	huang ying <huang.ying.caritas@...il.com>
Cc:	Huang Ying <ying.huang@...el.com>,
	Robert Richter <robert.richter@....com>,
	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Andi Kleen <andi@...stfloor.org>
Subject: Re: [PATCH -v2 7/7] x86, NMI, Remove do_nmi_callback logic

On Wed, Sep 29, 2010 at 02:55:58PM +0800, huang ying wrote:
> Hi, Don,
> 
> I think we all agree that to use order to determine the reason/source
> of NMI. The difference is that I want to keep as many direct calls in
> default_do_nmi() as possible, while you guys want to wrap almost all
> code in default_do_nmi() into notifier handler and leave only one
> notify_die() in defualt_do_nmi(). And I want to use different die_val
> (and their calling order in default_do_nmi()) to determine the order
> while you guys want to use priority (based on its value) to determine
> the order.

Well, I just wanted to see if we can minimize the number of times we
walked the die_chain.  Priorities was an interesting idea, I am not sure
it works out.  Registering two handlers, seems clunky.  But I am open to
the discussions.

> 
> On the other hand, I think we should call corresponding DIE_NMIxxx
> before the default operations, such as for watchdog, call
> DIE_NMIWATCHDOG before go panic, for unknown nmi, call DIE_NMIUNKNOWN
> before the default processing (may panic).
> 
> I think it is important to distinguish between die chain used to
> determine the source/reason of NMI and the die chain used to see if
> any other driver wanted to do some processing before the default
> operation.

I guess I still prefer to take your patch set with its change and then
layer any new ideas on top.  I have a feeling this discussion could go on
forever regarding how die_chains can work.

Cheers,
Don
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