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Date:   Wed, 24 Mar 2021 13:23:41 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Vitaly Wool <vitaly.wool@konsulko.com>
Cc:     guoren@kernel.org, linux-riscv <linux-riscv@lists.infradead.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Guo Ren <guoren@linux.alibaba.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Palmer Dabbelt <palmerdabbelt@google.com>,
        Anup Patel <anup@brainfault.org>, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH] riscv: locks: introduce ticket-based spinlock
 implementation
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 <CAM4kBBK7_s9U2vJbq68yC8WdDEfPQTaCOvn1xds3Si5B-Wpw+A@mail.gmail.com>
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On Wed, Mar 24, 2021 at 12:15:47PM +0100, Vitaly Wool wrote:
> On Wed, Mar 24, 2021, 11:16 AM <guoren@kernel.org> wrote:
> 
> > From: Guo Ren <guoren@linux.alibaba.com>
> >
> > This patch introduces a ticket lock implementation for riscv, along the
> > same lines as the implementation for arch/arm & arch/csky.
> >
> 
> Could you please provide a rationale for this? Like, what is wrong with the
> current implementation.

test-and-set spinlocks have terrible worst case behaviour.