From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757912AbcBXFHr (ORCPT ); Wed, 24 Feb 2016 00:07:47 -0500 Received: from e19.ny.us.ibm.com ([129.33.205.209]:45401 "EHLO e19.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757782AbcBXFHl (ORCPT ); Wed, 24 Feb 2016 00:07:41 -0500 X-IBM-Helo: d01dlp02.pok.ibm.com X-IBM-MailFrom: paulmck@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, SeongJae Park , "Paul E. McKenney" Subject: [PATCH tip/core/rcu 14/14] documentation: Clarify compiler store-fusion example Date: Tue, 23 Feb 2016 21:00:47 -0800 Message-Id: <1456290047-16654-14-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 2.5.2 In-Reply-To: <20160224050021.GA14616@linux.vnet.ibm.com> References: <20160224050021.GA14616@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16022405-0057-0000-0000-0000038307FA Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: SeongJae Park The compiler store-fusion example in memory-barriers.txt uses a C comment to represent arbitrary code that does not update a given variable. Unfortunately, someone could reasonably interpret the comment as instead referring to the following line of code. This commit therefore replaces the comment with a string that more clearly represents the arbitrary code. Signed-off-by: SeongJae Park Acked-by: David Howells Signed-off-by: Paul E. McKenney --- Documentation/memory-barriers.txt | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt index 8367d393cba2..3729cbe60e41 100644 --- a/Documentation/memory-barriers.txt +++ b/Documentation/memory-barriers.txt @@ -1550,7 +1550,7 @@ of optimizations: the following: a = 0; - /* Code that does not store to variable a. */ + ... Code that does not store to variable a ... a = 0; The compiler sees that the value of variable 'a' is already zero, so @@ -1562,7 +1562,7 @@ of optimizations: wrong guess: WRITE_ONCE(a, 0); - /* Code that does not store to variable a. */ + ... Code that does not store to variable a ... WRITE_ONCE(a, 0); (*) The compiler is within its rights to reorder memory accesses unless -- 2.5.2