Re: [PATCH] Documentation/memory-barriers: fix wrong comment in example

From: David Howells
Date: Mon Feb 22 2016 - 06:16:51 EST


SeongJae Park <sj38.park@xxxxxxxxx> wrote:

> From f7b5677790771599f418f1d95536935be971ae86 Mon Sep 17 00:00:00 2001
> From: SeongJae Park <sj38.park@xxxxxxxxx>
> Date: Mon, 22 Feb 2016 19:26:18 +0900
> Subject: [PATCH] Documentation/memory-barriers: polish compiler store omit
> example
>
> Comments of examples about compiler store omit in memory-barriers.txt is
> about code that could be possible at that point. However, someone could
> interpret the comment as an explanation about below line. This commit
> exploits the intent more explicitly by changing the comment to be seems
> like a possible code rather than explanation about below line.
>
> Signed-off-by: SeongJae Park <sj38.park@xxxxxxxxx>
> ---
> 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 904ee42..dc66351 100644
> --- a/Documentation/memory-barriers.txt
> +++ b/Documentation/memory-barriers.txt
> @@ -1459,7 +1459,7 @@ 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
> @@ -1471,7 +1471,7 @@ 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

Acked-by: David Howells <dhowells@xxxxxxxxxx>