linux-kernel - Re: [PATCH 0/7] x86: Clean up percpu operations

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Message-ID: <CAKwvOd=ch9L2n0nCOmH6nQ67zOXW-R9GV5wbWVha3ScGedrgQg@mail.gmail.com>
Date:   Mon, 18 May 2020 12:19:59 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Brian Gerst <brgerst@...il.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH 0/7] x86: Clean up percpu operations

On Sun, May 17, 2020 at 8:29 AM Brian Gerst <brgerst@...il.com> wrote:
>
> The core percpu operations already have a switch on the width of the
> data type, which resulted in an extra amount of dead code being

Thanks for the series Brian.  The duplication between knowing the size
at the call site and the switch is exactly what I picked up on, too.
This past weekend I started a similar cleanup, but only got through 2
of the 6 functions you cleaned up.  And via quick glance, your series
looks much better than mine does.  I'll sit down and review+test these
after lunch.  I appreciate you taking the time to create this series.

> generated with the x86 operations having another switch.  This patch set
> rewrites the x86 ops to remove the switch.  Additional cleanups are to
> use named assembly operands, and to cast variables to the width used in
> the assembly to make Clang happy.
>
> Brian Gerst (7):
>   x86/percpu: Introduce size abstraction macros
>   x86/percpu: Clean up percpu_to_op()
>   x86/percpu: Clean up percpu_from_op()
>   x86/percpu: Clean up percpu_add_op()
>   x86/percpu: Clean up percpu_add_return_op()
>   x86/percpu: Clean up percpu_xchg_op()
>   x86/percpu: Clean up percpu_cmpxchg_op()
>
>  arch/x86/include/asm/percpu.h | 447 ++++++++++++----------------------
>  1 file changed, 158 insertions(+), 289 deletions(-)
>
> --
> 2.25.4
>


-- 
Thanks,
~Nick Desaulniers