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From:   Huacai Chen <chenhuacai@kernel.org>
Date:   Tue, 17 Jan 2023 09:38:11 +0800
Message-ID: <CAAhV-H7KpR3wKUYVR2mSfbCuwbONAmPwSB9oaLAE-4zGhx1r4g@mail.gmail.com>
Subject: Re: [PATCH 1/4] LoongArch: Use trampoline for exception handlers and
 kill la.abs
To:     Xi Ruoyao <xry111@xry111.site>
Cc:     Jinyang He <hejinyang@loongson.cn>,
        Youling Tang <tangyouling@loongson.cn>,
        Xuerui Wang <kernel@xen0n.name>, loongarch@lists.linux.dev,
        linux-kernel@vger.kernel.org
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On Mon, Jan 16, 2023 at 1:41 PM Xi Ruoyao <xry111@xry111.site> wrote:
>
> On Mon, 2023-01-16 at 09:30 +0800, Huacai Chen wrote:
> > On Sat, Jan 14, 2023 at 2:38 PM Jinyang He <hejinyang@loongson.cn>
> > wrote:
> > >
> > > Hi, Ruoyao and Youling,
> > >
> > > I care about the performance when NUMA enabled. We set CSR.EENTRY
> > > for each possible cpus where is NUMA-relative. So, I guess the more
> > > codes in NUMA-relative memory makes more performance. If we just set
> > > handler_trampoline as exception handler, the performance may be
> > > influenced.
> > So copying both the handlers and handler_trampoline can solve the
> > problem? If that is possible, please do that on top of the latest code
> > in
> > https://github.com/loongson/linux/commits/loongarch-next
>
> Hi folks,
>
> I just wrote the trampoline code as a PoC to show "relocatable kernel
> can work" and there must be some better way.  But I'm too sad to write
> any serious code in this month, and I don't have access to a LoongArch
> NUMA system.  So I think it's better to leave the job for you guys now
> :).
Hmm, I hope this series can be merged in 6.3. :)

Huacai
>
> Best regards
>
> --
> Xi Ruoyao <xry111@xry111.site>
> School of Aerospace Science and Technology, Xidian University