Messages in this thread | | | Date | Wed, 13 Aug 2014 15:50:17 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] doc: memory-barriers.txt: Add barrier() to provide ordering |
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On Mon, Aug 11, 2014 at 06:51:40PM -0400, Pranith Kumar wrote: > 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(); > }
This section had to be rewritten due to -O3.
Thanx, Paul
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