Re: [PATCH 3/3] early_printk: Add simple serialization to early_vprintk()

From: Paul E. McKenney
Date: Wed Oct 04 2017 - 11:38:44 EST


On Wed, Oct 04, 2017 at 05:24:23PM +0200, Peter Zijlstra wrote:
> On Wed, Oct 04, 2017 at 07:17:45AM -0700, Paul E. McKenney wrote:
> > If you use READ_ONCE(), then all architectures I know of enforce
> > full ordering for accesses to a single variable. (If you don't use
> > READ_ONCE(), then in theory Itanium can reorder reads.) Me, I would
> > argue for WRITE_ONCE() as well to prevent store tearing.
>
> Note that the stores are either cmpxchg() or smp_store_release() both of
> which imply a WRITE_ONCE().

That works for me! ;-)

Thanx, Paul