local64_cmpxchg() in arc_perf_event_update()

[Peter Zijlstra]

On Tue, Nov 17, 2015 at 01:24:01PM +0100, Peter Zijlstra wrote:
> On Tue, Nov 17, 2015 at 04:53:04PM +0530, Vineet Gupta wrote:
> > That means Alexey need to revert the hunk ?
> 
> Yes, I think so.

This is assuming you now have these NMIs we talked about earlier. If all
you have are regular IRQs this is not possible, for we should be calling
->read() with IRQs disabled.