Re: [RFC PATCH 3/6] perf: Generalize some arch callchain code

[Peter Zijlstra]

On Thu, 2010-07-01 at 17:49 +0200, Frederic Weisbecker wrote:
> On Thu, Jul 01, 2010 at 05:46:01PM +0200, Peter Zijlstra wrote:
> > On Thu, 2010-07-01 at 17:35 +0200, Frederic Weisbecker wrote:
> > > - Most archs use one callchain buffer per cpu, except x86 that needs
> > >   to deal with NMIs. Provide a default perf_callchain_buffer()
> > >   implementation that x86 overrides. 
> > 
> > sparc and power also have NMI like contexts.
> 
> 
> Ah and the comments suggest it's because pmu interrupts can't nest or so.
> Anyway, that's notwithstanding the race that 5th patch fixes.

Right, but they could interrupt a software event or the like.

But yeah, the whole callchain thing can nest issue is real, thanks for
fixing that.
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