On Wed, Oct 11, 2017 at 04:28:24PM +0100, David Howells wrote:
> Paul E. McKenney <[email protected]> wrote:
>
> > Placing the comment on the same line makes it less likely that some
> > later change will move the comment away from the load that it applies to.
>
> The problem with your 'address dep' comment is that it's not particularly
> useful.
>
> Either your comment needs to say "dep between X and Y", but if the following
> is
> always the dep:
>
> Y = READ_ONCE(X)
> access(*Y)
>
> then the comment is superfluous.
In assoc_array.c, the access is often quite some distance from the
corresponding READ_ONCE().
> If it's not always true then your comment needs to indicate what the
> dependency
> is.
Given that most READ_ONCE() calls aren't heading dependency chains,
a comment indicating that a particular READ_ONCE() does head a dependency
chain does provide at least some information. But, as you say below...
> The other thing your comment could/should say is where the other barrier is -
> barriers always have to be paired as a general rule. (I know I haven't put
> these comments in here - but I've been doing that recently).
I would welcome a patch that added the comments or help with what
the comments should say.
Thanx, Paul
