Re: [PATCH] mm/page_alloc: fix documentation error and remove magic numbers

[Matthew Wilcox]

On Wed, Jun 24, 2020 at 10:07:27AM -0400, Rafael Aquini wrote:
> On Wed, Jun 24, 2020 at 12:12:55PM +0100, Matthew Wilcox wrote:
> > On Tue, Jun 23, 2020 at 11:27:12PM -0400, Joel Savitz wrote:
> > > In addition, this patch replaces the magic number bounds with symbolic
> > > constants to clarify the logic.
> > 
> > Why do people think this kind of thing makes the code easier to read?
> > It actually makes it harder.  Unless the constants are used in more
> > than one place, just leave the numbers where they are.
> > 
> > > @@ -7852,6 +7852,9 @@ void setup_per_zone_wmarks(void)
> > >   * 8192MB:	11584k
> > >   * 16384MB:	16384k
> > >   */
> > > +static const int MIN_FREE_KBYTES_LOWER_BOUND = 1 << 7;
> > > +static const int MIN_FREE_KBYTES_UPPER_BOUND = 1 << 18;
> > > +
> 
> I think these constants would look better if declared as an enum.

Why does having to look in two different places make the code clearer?