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Date:   Mon, 30 Nov 2020 10:30:00 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Andy Lutomirski <luto@kernel.org>
Cc:     Nicholas Piggin <npiggin@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Arnd Bergmann <arnd@arndb.de>,
        linux-arch <linux-arch@vger.kernel.org>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        Linux-MM <linux-mm@kvack.org>, Anton Blanchard <anton@ozlabs.org>
Subject: Re: [PATCH 6/8] lazy tlb: shoot lazies, a non-refcounting lazy tlb
 option
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On Sat, Nov 28, 2020 at 07:54:57PM -0800, Andy Lutomirski wrote:
> This means that mm_cpumask operations won't need to be full barriers
> forever, and we might not want to take the implied full barriers in
> set_bit() and clear_bit() for granted.

There is no implied full barrier for those ops.