Re: [RFC PATCH v3 03/10] PM: Introduce an Energy Model management framework

From: Peter Zijlstra
Date: Tue Jun 19 2018 - 10:21:35 EST


On Tue, Jun 19, 2018 at 04:16:42PM +0200, Peter Zijlstra wrote:
> On Tue, Jun 19, 2018 at 02:38:45PM +0100, Quentin Perret wrote:
> > But maybe I could use something simpler than a lock in this case ?
> > Would WRITE_ONCE/READ_ONCE be enough to ensure that atomicity for
> > example ?
>
> Yes, since its a single pointer, smp_store_release() + READ_ONCE()
> should be sufficient (these are the foundations of RCU).

Note that per_cpu()/this_cpu_read() and friends should imply READ_ONCE().