From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH RFC tip/core/rcu 12/15] lib/assoc_array: Remove
 smp_read_barrier_depends()
Date: Wed, 11 Oct 2017 10:14:37 -0700
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To: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>, Will Deacon <will.deacon@arm.com>, linux-kernel@vger.kernel.org, mingo@kernel.org, torvalds@linux-foundation.org, mark.rutland@arm.com, linux-arch@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>, Alexander Kuleshov <kuleshovmail@gmail.com>, dvyukov@google.com

On Wed, Oct 11, 2017 at 10:06:31AM -0700, Paul E. McKenney wrote:
> On Wed, Oct 11, 2017 at 06:54:05PM +0200, Peter Zijlstra wrote:
> > On Wed, Oct 11, 2017 at 09:47:48AM -0700, Paul E. McKenney wrote:
> > > Interesting.  Do we currently have any dependencies headed by
> > > this_cpu_read()?
> > 
> > Nope, but almost, look for: cpufreq_update_util_data.
> 
> This, you mean?
> 
> data = rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data));
> 
> True, a non-RCU dependency use case would want to use ACCESS_ONCE()
> in the new regime.

Right...  s/ACCESS_ONCE()/READ_ONCE()/

							Thanx, Paul