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From: David Laight <david.laight.linux@gmail.com>
To: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: "Colin Ian King" <colin.i.king@gmail.com>,
	"Duje Mihanović" <duje@dujemihanovic.xyz>,
	"Jonathan Cameron" <jic23@kernel.org>,
	"David Lechner" <dlechner@baylibre.com>,
	"Nuno Sá" <nuno.sa@analog.com>,
	"Andy Shevchenko" <andy@kernel.org>,
	linux-iio@vger.kernel.org, kernel-janitors@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH][next] iio: adc: make read-only const array config static
Date: Wed, 15 Jul 2026 11:07:09 +0100	[thread overview]
Message-ID: <20260715110709.74f556f4@pumpkin> (raw)
In-Reply-To: <alZs-uLJug_rnRnq@ashevche-desk.local>

On Tue, 14 Jul 2026 20:08:10 +0300
Andy Shevchenko <andriy.shevchenko@intel.com> wrote:

> On Tue, Jul 14, 2026 at 05:50:12PM +0100, Colin Ian King wrote:
> > Don't populate the read-only const array config on the stack at run
> > time, instead make it static.  
> 
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
> 
> ...
> 
> In all patches like this it's always a bikeshedding possible of moving static
> data outside of a function. I have no strong opinion in these cases (when the
> data solely used by a single function), but in general it might give different
> readability experience (it's harder to notice static data in the local function
> definition block). So I leave this exercise to the maintainers of the respective
> pieces of the code.
> 

If global you start wondering where it is used....

There is also the fact that run-time initialisation of a 3 byte array
on stack is very likely to generate faster code than using static data.
Mostly because the access to the static data is likely to be a cache miss.

Then there are the architectures where just generating the address of
the static data takes multiple instructions.
In that case the on-stack version may even be smaller.

	David

  reply	other threads:[~2026-07-15 10:07 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-14 16:50 [PATCH][next] iio: adc: make read-only const array config static Colin Ian King
2026-07-14 17:08 ` Andy Shevchenko
2026-07-15 10:07   ` David Laight [this message]
2026-07-15 10:22   ` Dan Carpenter
2026-07-15 13:32     ` Andy Shevchenko
2026-07-15 13:34       ` Colin King (gmail)
2026-07-15 13:54         ` Andy Shevchenko
2026-07-14 17:40 ` David Lechner

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