linux-kernel - Re: [PATCH] x86/resctrl: avoid compiler optimization in __resctrl_sched

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Message-ID: <CAHk-=whCA4-uc5WV_-68Mpmu-TiSv6fxkSjZ19zzcW9jpSxDvA@mail.gmail.com>
Date:   Tue, 7 Mar 2023 13:06:29 -0800
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Jakub Jelinek <jakub@...hat.com>
Cc:     Segher Boessenkool <segher@...nel.crashing.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Stephane Eranian <eranian@...gle.com>,
        linux-kernel@...r.kernel.org, tony.luck@...el.com,
        reinette.chatre@...el.com, fenghua.yu@...el.com,
        peternewman@...gle.com, james.morse@....com, babu.moger@....com,
        ananth.narayan@....com, vschneid@...hat.com,
        Nathan Chancellor <nathan@...nel.org>,
        clang-built-linux <llvm@...ts.linux.dev>,
        Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>, linux-toolchains@...r.kernel.org
Subject: Re: [PATCH] x86/resctrl: avoid compiler optimization in __resctrl_sched_in

On Tue, Mar 7, 2023 at 12:54 PM Linus Torvalds
<torvalds@...ux-foundation.org> wrote:
>
> I think the problem is that the <asm/resctrl.h> code is disgusting and
> horrible in multiple ways:
>
>  (a) it shouldn't define and declare a static function in a header file
>
>  (b) the resctrl_sched_in() inline function is misdesigned to begin with

Ok, so here's a *ttoally* untested and mindless patch to maybe fix
what I dislike about that resctl code.

Does it fix the code generation issue? I have no idea. But this is
what I would suggest is the right answer, without actually knowing the
code any better, and just going on a mindless rampage.

It seems to compile for me, fwiw.

             Linus

View attachment "patch.diff" of type "text/x-patch" (3368 bytes)