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 <[email protected]>
> ---
> 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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