linux-kernel - Re: [PATCH] regmap: Reorder fields in 'struct regmap

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Message-ID: <ZAX4wSFwKwr+2pZY@smile.fi.intel.com>
Date:   Mon, 6 Mar 2023 16:29:21 +0200
From:   Andy Shevchenko <andriy.shevchenko@...el.com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc:     Mark Brown <broonie@...nel.org>, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] regmap: Reorder fields in 'struct regmap_bus' to save
 some memory

On Tue, Feb 14, 2023 at 09:40:14AM +0100, Christophe JAILLET wrote:
> Group some bool variables to reduce hole and avoid padding.
> On x86_64, this shrinks the size from 136 to 128 bytes.
> 
> As an example:
> 
> $ size drivers/base/regmap/regmap-fsi.o (Before)
>    text	   data	    bss	    dec	    hex	filename
>    4837	    136	      0	   4973	   136d	drivers/base/regmap/regmap-fsi.o
> 
> $ size drivers/base/regmap/regmap-fsi.o (After)
>    text	   data	    bss	    dec	    hex	filename
>    4701	    136	      0	   4837	   12e5	drivers/base/regmap/regmap-fsi.o

FYI: we have scripts/bloat-o-meter for this.

-- 
With Best Regards,
Andy Shevchenko