[PATCH v2 4/4] nmi_backtrace: generate one-line reports for idle cpus

[Peter Zijlstra]

On Wed, Mar 16, 2016 at 01:02:13PM -0400, Chris Metcalf wrote:
> When doing an nmi backtrace of many cores, most of which are idle,
> the output is a little overwhelming and very uninformative.  Suppress
> messages for cpus that are idling when they are interrupted and just
> emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN".

This is still 100+ lines on a modern system, but better than the many
many thousands it would otherwise generate.

> We do this by grouping all the cpuidle code together into a new
> .cpuidle.text section, and then checking the address of the
> interrupted PC to see if it lies within that section.
> 
> Signed-off-by: Chris Metcalf <cmetcalf at mellanox.com>

Acked-by: Peter Zijlstra (Intel) <peterz at infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz at infradead.org>

Please Cc Rafael on the next posting.