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Date: Wed, 4 Oct 2017 17:24:23 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>, pmladek@suse.com,
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Subject: Re: [PATCH 3/3] early_printk: Add simple serialization to
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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().