linux-kernel - Re: [PATCH] x86/math64: handle #DE in mul_u64_u64_div

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Message-ID: <4d6275f1-f3a4-4d70-9c25-42bd4563c6d0@zytor.com>
Date: Tue, 22 Jul 2025 12:26:44 -0700
From: "H. Peter Anvin" <hpa@...or.com>
To: Oleg Nesterov <oleg@...hat.com>
Cc: David Laight <david.laight.linux@...il.com>,
        Ingo Molnar <mingo@...hat.com>, Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "Li,Rongqing"
 <lirongqing@...du.com>,
        Steven Rostedt <rostedt@...dmis.org>, linux-kernel@...r.kernel.org,
        x86@...nel.org
Subject: Re: [PATCH] x86/math64: handle #DE in mul_u64_u64_div_u64()

On 2025-07-22 11:38, Oleg Nesterov wrote:
>>
>> But that's what you want to optimize for, since that is all the modern compilers, even if you have to have two versions as a result.
> 
> Well, this 'divq' is slow anyway, I don't won't to add 2 versions.
> Can we add the optimized version later if it really makes sense?
> 

Then it will guaranteed get forgotten.

	-hpa