linux-kernel - Re: [PATCH v2 1/1] x86/reboot: KVM: Guard nmi_shootdown_cpus_on

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Message-ID: <2F60FA75-E4F4-41F3-BD5D-EAECBE57A3A4@zytor.com>
Date: Fri, 02 May 2025 13:59:30 -0700
From: "H. Peter Anvin" <hpa@...or.com>
To: Dave Hansen <dave.hansen@...el.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
CC: Sean Christopherson <seanjc@...gle.com>, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Bill Wendling <morbo@...gle.com>,
        Justin Stitt <justinstitt@...gle.com>
Subject: Re: [PATCH v2 1/1] x86/reboot: KVM: Guard nmi_shootdown_cpus_on_restart() with ifdeffery

On May 2, 2025 7:24:37 AM PDT, Dave Hansen <dave.hansen@...el.com> wrote:
>On 5/2/25 07:04, Andy Shevchenko wrote:
>> Can it be applied, please? The problem still persists as of today (v6.15-rc4).
>
>I fundamentally disagree with the idea that the kernel programmer should
>be doing the work of telling the compiler *exactly* when a static inline
>function is unused. Compilers are good at that, humans are not.
>
>The "fixes" for these issues generally make the code worse, not better.
>
>I'd frankly rather have a kernel with some unused 'static inline'
>functions in .c files than one filled with #ifdefs to shut up the compiler.
>

__attribute__((unused)) if they don't need to be inlined?