linux-kernel - Re: [PATCH] x86: static_cpu_has_safe: discard dynamic check after init

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Date:	Sun, 17 Jan 2016 11:33:38 +0100
From:	Borislav Petkov <bp@...e.de>
To:	Brian Gerst <brgerst@...il.com>
Cc:	the arch/x86 maintainers <x86@...nel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...nel.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	Andy Lutomirski <luto@...capital.net>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH] x86: static_cpu_has_safe: discard dynamic check after
 init

On Sat, Jan 16, 2016 at 02:58:21PM -0500, Brian Gerst wrote:
> It saves space.  The only thing left in main text is one jump
> instruction (5 bytes).

How do I measure this?

Because with my tailored config here, the only thing I'm seeing is a growth of
text by 730 bytes:

before:
   text    data     bss     dec     hex filename
10926552        3598944 16642048        31167544        1db9438 vmlinux

[    0.056552] Freeing SMP alternatives memory: 24K (ffffffff81dd7000 - ffffffff81ddd000)
[    2.883728] Freeing unused kernel memory: 2904K (ffffffff81b01000 - ffffffff81dd7000)


after:
   text    data     bss     dec     hex filename
10927282        3598944 16642048        31168274        1db9712 vmlinux

[    0.052559] Freeing SMP alternatives memory: 24K (ffffffff81dd7000 - ffffffff81ddd000)
[    3.225318] Freeing unused kernel memory: 2904K (ffffffff81b01000 - ffffffff81dd7000)

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--