Re: [PATCH v3 1/5] m68k/bitops: force inlining of all bitops functions

[Geert Uytterhoeven]

Hi Vincent,

Thanks for your patch!

On Sun, Dec 17, 2023 at 8:13 AM Vincent Mailhol
<mailhol.vincent@xxxxxxxxxx> wrote:
> The inline keyword actually does not guarantee that the compiler will
> inline a functions. Whenever the goal is to actually inline a
> function, __always_inline should always be preferred instead.
>
> On an allyesconfig, with GCC 13.2.1, it saves roughly 5 KB.
>
>   $ size --format=GNU vmlinux.before vmlinux.after
>         text       data        bss      total filename
>     60449738   70975612    2288988  133714338 vmlinux.before
>     60446534   70972412    2289596  133708542 vmlinux.after

With gcc 9.5.0-1ubuntu1~22.04, the figures are completely different
(i.e. a size increase):

allyesconfig:

      text       data        bss      total filename
  58878600   72415994    2283652  133578246 vmlinux.before
  58882250   72419706    2284004  133585960 vmlinux.after

atari_defconfig:

      text       data        bss      total filename
   4112060    1579862     151680    5843602 vmlinux-v6.7-rc8
   4117008    1579350     151680    5848038
vmlinux-v6.7-rc8-1-m68k-bitops-force-inlining

The next patch offsets that for allyesconfig, but not for atari_defconfig.

> Reference: commit 8dd5032d9c54 ("x86/asm/bitops: Force inlining of
> test_and_set_bit and friends")

Please don't split lines containing tags.

> Link: https://git.kernel.org/torvalds/c/8dd5032d9c54
>
> Signed-off-by: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx>

Reviewed-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds