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SubjectRe: [PATCH 2/4] nmi_backtrace: generate one-line reports for idle cpus
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On 03/07/2016 03:26 AM, Daniel Thompson wrote:
>> Chris Metcalf wrote:
>> +static DEFINE_PER_CPU(bool, cpu_idling);
>> +
>> +/* Was the cpu was in the low-level idle code when interrupted? */
>> +bool in_cpu_idle(void)
>> +{
>> + return this_cpu_read(cpu_idling);
>
> I think we continue to need the code to identify a core that is
> running an interrupt handler. Interrupts are not masked at the point
> we set cpu_idling to false meaning we can easily be preempted before
> we clear the flag.

Yes, good catch. However, mooted by PeterZ wanting to keep any extra
state-switching code out of the idle path. See my reply to him for more
on that.

--
Chris Metcalf, Mellanox Technologies
http://www.mellanox.com

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