Re: [PATCH RFC] percpu: add data dependency barrier in percpu accessors and operations

From: Christoph Lameter
Date: Tue Jul 15 2014 - 10:06:14 EST

On Tue, 15 Jul 2014, Paul E. McKenney wrote:

> If I understand your initialization procedure correctly, you need at least
> an smp_wmb() on the update side and at least an smp_read_barrier_depends()
> on the read side.

A barrier for data that is not in the cache of the read side? That has
not been accessed yet (well there could have been a free_percpu before but
if so then the cache line was evicted by the initialization code).

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