Re: [PATCH 1/6] perf/core: Provide a kernel-internal interface toget to performance counters

From: Arjan van de Ven
Date: Mon Nov 02 2009 - 00:37:50 EST

On Mon, 2 Nov 2009 14:46:55 +1100
Paul Mackerras <paulus@xxxxxxxxx> wrote:

> Frederic Weisbecker writes:
> > /*
> > + * perf_event_create_kernel_counter
> > + * MUST be called from a kernel thread.
> Why? The reason for this requirement isn't obvious to me. It would
> be good to have the reason documented in the comment for the sake of
> people modifying the code in future.

because if you call it from another context it will attach to that
context... and go away when that context goes away...

Arjan van de Ven Intel Open Source Technology Centre
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