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Date:   Wed, 24 Jun 2020 15:09:58 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     Rafael Aquini <aquini@redhat.com>
Cc:     Joel Savitz <jsavitz@redhat.com>, linux-kernel@vger.kernel.org,
        Vlastimil Babka <vbabka@suse.cz>,
        John Hubbard <jhubbard@nvidia.com>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org
Subject: Re: [PATCH] mm/page_alloc: fix documentation error and remove magic
 numbers
Message-ID: <20200624140958.GN21350@casper.infradead.org>
References: <20200624032712.23263-1-jsavitz@redhat.com>
 <20200624111255.GL21350@casper.infradead.org>
 <20200624140727.GA1987277@optiplex-lnx>
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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?