linux-kernel - Re: [PATCH 01/26] mm: asi: Make some utility functions noinstr compatible

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Message-ID: <CA+i-1C0HKQS=SczTJEOsJLiUzhb60zAdi+27ey6VCLU5Ws9pfg@mail.gmail.com>
Date: Fri, 1 Nov 2024 11:06:57 +0100
From: Brendan Jackman <jackmanb@...gle.com>
To: Junaid Shahid <junaids@...gle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, Borislav Petkov <bp@...en8.de>, Ingo Molnar <mingo@...hat.com>, 
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Subject: Re: [PATCH 01/26] mm: asi: Make some utility functions noinstr compatible

On Fri, 1 Nov 2024 at 02:44, Junaid Shahid <junaids@...gle.com> wrote:
> In any case, I guess we could just mark these functions as plain noinstr.

I wonder if it also would be worth having something like

/*
 * Inline this function so it can be called from noinstr,
 * but it wouldn't actually care itself about being instrumented.
 */
#define inline_for_noinstr __always_inline

Maybe there are already __always_inline functions this would apply to.
Then again, if you care about inlining them so much that you can't
just write "noinstr", then it's probably hot/small enough that
__always_inline would make sense regardless of noinstr.

Probably I'm over-thinking it at this point.