Re: [PATCH] x86/vdso: shrink vdso/extable.i via IWYU

From: Borislav Petkov <bp@alien8.de>
To: Tanzir Hasan <tanzirh@google.com>
Cc: Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	linux-kernel@vger.kernel.org, Nick Desaulniers <nnn@google.com>
Subject: Re: [PATCH] x86/vdso: shrink vdso/extable.i via IWYU
Date: Fri, 29 Dec 2023 10:39:42 +0100	[thread overview]
Message-ID: <20231229093942.GBZY6T3knaGKpeRA9a@fat_crate.local> (raw)
In-Reply-To: <CAE-cH4rEWU-+ovwo8_-i3b2F8pK17kORJ3gV5tnjnUpRJA+B0Q@mail.gmail.com>

On Thu, Dec 28, 2023 at 02:01:20PM -0800, Tanzir Hasan wrote:
> The intention with these changes is to add up the impact of these small changes
> over time to improve build time and also use more direct inclusions where
> possible.

The problem I see with such "changes" is that it'll be a never-ending
stream of them because over time, headers get reworked, moved, changed,
split, etc and one would have to do such reorganization again.

And I'd understand it if the benefits were higher than what you're
seeing. But right now it looks like unnecessary churn.

Dunno, perhaps one could do those in one single patch for, say,
on arch/x86/ or so, and show a before and after wrt numbers. And then do it
again in a couple of releases, when it becomes necessary again.

Or one could run that tool on patches which haven't been applied yet,
patches on lkml.

Patches which touch headers or add #include directives and then reply
with an automatic report to them, saying something along the lines of

"your patch has a suboptimal include - if you include this and that,
it'll improve build time by this and that"

and then people would incorporate those changes and right then and
there.

But let's see what the others think first.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette