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From:   WANG Rui <wangrui@loongson.cn>
Date:   Wed, 2 Aug 2023 00:36:54 +0800
Message-ID: <CAHirt9i_osW_Dy5jNAnNOKrm-+38qN7SF+8ofNHePMAYhRKHsA@mail.gmail.com>
Subject: Re: [PATCH] LoongArch: Fixup cmpxchg sematic for memory barrier
To:     Guo Ren <guoren@kernel.org>
Cc:     chenhuacai@kernel.or, kernel@xen0n.name, arnd@arndb.de,
        andi.shyti@linux.intel.com, andrzej.hajda@intel.com,
        peterz@infradead.org, will@kernel.org, boqun.feng@gmail.com,
        mark.rutland@arm.com, loongarch@lists.linux.dev,
        linux-kernel@vger.kernel.org, Guo Ren <guoren@linux.alibaba.com>
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On Tue, Aug 1, 2023 at 6:50 PM Guo Ren <guoren@kernel.org> wrote:
>
> On Tue, Aug 1, 2023 at 5:32 PM WANG Rui <wangrui@loongson.cn> wrote:
> > No. LL and LL won't reorder because LL implies a memory barrier(though
> > not acquire semantics).
> That means we could remove __WEAK_LLSC_MB totally, right?

More precisely, __WEAK_LLSC_MB is intended to prevent reordering
between LL and normal LD used to fetch the expected value for cmpxchg.

Regards,
-- 
WANG Rui