Re: [RFC][PATCH] perf, intel: Don't touch MSR_IA32_DEBUGCTLMSR fromNMI context

From: Peter Zijlstra
Date: Thu Sep 13 2012 - 08:12:16 EST

On Thu, 2012-09-13 at 13:49 +0200, Stephane Eranian wrote:
> Should be, though it is pretty ugly to stash all of this in the
> put/get constraints.

Agreed, I almost added two extra functions for it but when I went to
look at where to call them I ended up next to get/put constraints.

> I will run some tests.
> I wonder what this does when you come in to get/put with a fake cpuc. You don't
> want to perturb the local lbr which may be in use.

Fake cpu will never set ->alloc and thus intel_pmu_has_lbr() should fail
and we don't do anything.
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