From: Pranith Kumar <bobby.prani@gmail.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
David Howells <dhowells@redhat.com>,
Masanari Iida <standby24x7@gmail.com>,
linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] doc: memory-barriers.txt: Add barrier() to provide ordering
Date: Mon, 11 Aug 2014 18:51:40 -0400 [thread overview]
Message-ID: <1407797503-24727-2-git-send-email-bobby.prani@gmail.com> (raw)
In-Reply-To: <1407797503-24727-1-git-send-email-bobby.prani@gmail.com>
In the provably false case, add barrier() in both the legs of the if() condition
to provide ordering.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
---
Documentation/memory-barriers.txt | 2 ++
1 file changed, 2 insertions(+)
diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt
index 41a6c9c..0f2903f 100644
--- a/Documentation/memory-barriers.txt
+++ b/Documentation/memory-barriers.txt
@@ -689,9 +689,11 @@ should do something like the following:
q = ACCESS_ONCE(a);
BUILD_BUG_ON(MAX <= 1); /* Order load from a with store to b. */
if (q % MAX) {
+ barrier();
ACCESS_ONCE(b) = p;
do_something();
} else {
+ barrier();
ACCESS_ONCE(b) = p;
do_something_else();
}
--
1.9.1
next prev parent reply other threads:[~2014-08-11 22:52 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-11 22:51 [PATCH] doc: memory-barriers.txt: Minor correction in Control dependencies Pranith Kumar
2014-08-11 22:51 ` Pranith Kumar [this message]
2014-08-13 22:50 ` [PATCH] doc: memory-barriers.txt: Add barrier() to provide ordering Paul E. McKenney
2014-08-11 22:51 ` [PATCH] sched: Remove ACCESS_ONCE() for jiffies Pranith Kumar
2014-08-12 5:55 ` Peter Zijlstra
2014-08-12 14:42 ` Pranith Kumar
2014-08-12 22:11 ` David Rientjes
2014-08-11 22:51 ` [PATCH] compiler.h: Move __memory_barrier() use to compiler-intel.h Pranith Kumar
2014-08-13 22:49 ` [PATCH] doc: memory-barriers.txt: Minor correction in Control dependencies Paul E. McKenney
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