On Tue, Jan 29, 2019 at 01:38:43PM +0100, Peter Zijlstra wrote:
> 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_.
Also; the comment should explain _why_ not only what.
