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From: Huacai Chen <chenhuacai@kernel.org>
Date: Sat, 13 Apr 2024 15:20:08 +0800
Message-ID: <CAAhV-H7AUxqecu7f=TmdteBG6biudDGk2T+wkZvboMdVw=8ScQ@mail.gmail.com>
Subject: Re: [PATCH v3 1/4] LoongArch: Move CONFIG_HAVE_SETUP_PER_CPU_AREA
 related code to smp.c
To: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Thomas Gleixner <tglx@linutronix.de>, Arnd Bergmann <arnd@arndb.de>, Marc Zyngier <maz@kernel.org>, 
	loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, 
	loongson-kernel@lists.loongnix.cn
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On Fri, Apr 12, 2024 at 5:27=E2=80=AFPM Tiezhu Yang <yangtiezhu@loongson.cn=
> wrote:
>
>
>
> On 04/12/2024 12:12 PM, Huacai Chen wrote:
> > On Thu, Apr 11, 2024 at 9:05=E2=80=AFAM Tiezhu Yang <yangtiezhu@loongso=
n.cn> wrote:
> >>
> >> Currently, if CONFIG_NUMA is not set but CONFIG_SMP is set, the arch
> >> specified setup_per_cpu_areas() in arch/loongarch/kernel/numa.c will
> >> not be built and the generic setup_per_cpu_areas() in mm/percpu.c is
> >> actually used, this is not reasonable and does not work as intended.
> > Why is the generic version not reasonable? We need a custom version
> > just because it can put the percpu variable in the best node. If NUMA
> > disabled, software can only see one node, how to optimize?
>
> The initial aim is to use the arch specific setup_per_cpu_areas()
> in any case under CONFIG_SMP, this patch can be dropped if it is
> meaningless for the case of !CONFIG_NUMA and CONFIG_SMP.
Yes, it is better to drop this patch.

Huacai
>
> Thanks,
> Tiezhu
>
>