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Date:   Thu, 10 Aug 2023 16:13:32 +0300
From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     David Laight <David.Laight@aculab.com>
Cc:     'Petr Mladek' <pmladek@suse.com>, Marco Elver <elver@google.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
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        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v2 2/3] lib/vsprintf: Split out sprintf() and friends
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On Wed, Aug 09, 2023 at 08:48:54AM +0000, David Laight wrote:
> ...
> > If you split headers into so many small pieces then all
> > source files will start with 3 screens of includes. I do not see
> > how this helps with maintainability.
> 
> You also slow down compilations.

Ingo's patches showed the opposite. Do you have actual try and numbers?

> A few extra definitions in a 'leaf' header (one without any
> #includes) don't really matter.
> If a header includes other 'leaf' headers that doesn't matter
> much.
> 
> But the deep include chains caused by a low level header
> including a main header are what causes pretty much every
> header to get included in every compilation.
> 
> Breaking the deep chains is probably more useful than
> adding leaf headers for things that are in a header pretty
> much everything in going to include anyway.
> 
> The is probably scope for counting the depth of header
> includes by looking at what each header includes.

-- 
With Best Regards,
Andy Shevchenko