linux-kernel - Re: [PATCH -tip 2/2] x86/hweight: Use POPCNT when available with X86_NATIVE

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Message-ID: <20250330173140.GCZ-l__PVdSx6mj-zL@fat_crate.local>
Date: Sun, 30 Mar 2025 19:31:40 +0200
From: Borislav Petkov <bp@...en8.de>
To: Uros Bizjak <ubizjak@...il.com>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...nel.org>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH -tip 2/2] x86/hweight: Use POPCNT when available with
 X86_NATIVE_CPU option

On Sun, Mar 30, 2025 at 05:15:16PM +0200, Uros Bizjak wrote:
> You missed this part:
> 
> --q--
> ... where there is no need for an entry in the .altinstr_replacement

Not really - .altinstr* memory gets jettisoned after boot.

> section, shrinking all text sections by 9476 bytes:

So if anything, this saves a whopping ~9K disk space and makes hweight* an
unreadable mess.

So no, thanks.

-- 
Regards/Gruss,
    Boris.

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