Re: [PATCH v3 5/5] psi: introduce psi monitor

[Peter Zijlstra]

On Thu, Jan 24, 2019 at 01:15:18PM -0800, Suren Baghdasaryan wrote:
> +			atomic_set(&group->polling, polling);
> +			/*
> +			 * Memory barrier is needed to order group->polling
> +			 * write before times[] read in collect_percpu_times()
> +			 */
> +			smp_mb__after_atomic();

That's broken, smp_mb__{before,after}_atomic() can only be used on
atomic RmW operations, something atomic_set() is _not_.