[m-rev.] for post-commit review: O(n^2) to O(n log n)

[Peter Wang]

On Mon, 10 Jan 2022 08:52:02 +1100 "Zoltan Somogyi" <zoltan.somogyi at runbox.com> wrote:
> For post-commit review by anyone, mostly of the comment
> about an even faster, cleaner algorithm.
> 
> Zoltan.

> Improve O(n^2) algorithm to O(n log n).
> 
> And add a long comment about a possible even faster, cleaner algorithm.

> +    %
> +    %   However, this consideration never applies only to a single module;
> +    %   if the default set of option values changes, it applies for all
> +    %   modules. Therefore it would be enough to record a hash of the
> +    %   default values of all options *once* as a "global" value in the
> +    %   MODULE.track_flags file, which, if it changes, invalidates *every*
> +    %   module-specific entry in that file.

I don't understand that. Currently there is one .track_flags file per
module.

Peter