Re: [PATCH -v3] perf, x86: try to handle unknown nmis with running perfctrs

Robert Richter
2010-08-19T12:39:37Z

On 19.08.10 06:45:53, Peter Zijlstra wrote:
> I queued it with that part changed to:
>
> + this_nmi = percpu_read(irq_stat.__nmi_count);
> + if ((handled > 1) ||
> + /* the next nmi could be a back-to-back nmi */
> + ((__get_cpu_var(nmi).marked == this_nmi) &&
> + (__get_cpu_var(nmi).handled > 1))) {
> + /*
> + * We could have two subsequent back-to-back nmis: The
> + * first handles more than one counter, the 2nd
> + * handles only one counter and the 3rd handles no
> + * counter.
> + *
> + * This is the 2nd nmi because the previous was
> + * handling more than one counter. We will mark the
> + * next (3rd) and then drop it if unhandled.
> + */
> + __get_cpu_var(nmi).marked = this_nmi + 1;
> + __get_cpu_var(nmi).handled = handled;
> + }
>
> return NOTIFY_STOP;
> }

I am fine with this. Thanks Peter.

-Robert

--
Advanced Micro Devices, Inc.
Operating System Research Center