Re: [PATCH 1/2] x86/platform: Add a low priority low frequency NMI call chain

[Ingo Molnar <mingo@kernel.org>]

* Mike Travis <mike.travis@hpe.com> wrote:

> Add a new NMI call chain that is called last after all other NMI handlers
> have been checked and did not "handle" the NMI.  This mimics the current
> NMI_UNKNOWN call chain except it eliminates the WARNING message about
> multiple NMI handlers registering on this call chain.
> 
> This call chain dramatically lowers the NMI call frequency when high
> frequency NMI tools are in use, notably the perf tools.  It is required
> for NMI handlers that cannot sustain a high NMI call rate without
> ramifications to the system operability.

So how about we just turn off that warning instead? I don't remember the last time 
it actually _helped_ us find any kernel or hardware bug - and it has caused tons 
of problems...

It's not like we warn about excess regular IRQs either - we either handle them or 
at most increase a counter somewhere. We could do the same for NMIs: introduce a 
counter somewhere that counts the number of seemingly unhandled NMIs.

But in any case, we should not spam the kernel log, neither with high, nor with 
low frequency.

Thanks,

	Ingo