linux-kernel - Re: [PATCH RESEND] x86/asm/32: Modernize

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Message-ID: <44af06e3-cb91-4361-b83b-850fc3942aa7@intel.com>
Date: Tue, 16 Dec 2025 08:38:05 -0800
From: Dave Hansen <dave.hansen@...el.com>
To: Uros Bizjak <ubizjak@...il.com>,
 David Laight <david.laight.linux@...il.com>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org,
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...nel.org>,
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
 "H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH RESEND] x86/asm/32: Modernize _memcpy()

On 12/16/25 08:30, Uros Bizjak wrote:
> I don't think that additional subtraction outweighs a move from EAX to
> a temporary.

There are basically two ways this can end up:

 1. None of these small changes (like an extra subtraction) matters in
    the end, and this is a debate about nothing. The simplest code wins.
 2. It matters and can be shown with some data.

Unfortunately, I see a lot more gazing into crystal balls than data
collection right now.