Re: local64_cmpxchg() in arc_perf_event_update()

From: Peter Zijlstra
Date: Tue Nov 17 2015 - 06:07:56 EST


On Tue, Nov 17, 2015 at 09:14:59AM +0000, Vineet Gupta wrote:
> Let's check with Peter as I'm not sure how exactly the read call will
> nest for same counter on same core ?

Various possible ways, but the easiest is userspace doing a sys_read()
on the counter while the NMI happens.


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