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From:   Christoph Bartoschek <bartoschek@google.com>
Date:   Wed, 27 Apr 2022 00:58:34 +0200
Message-ID: <CAAQBG5jnvSxcjwr+L5nuxwh87bv=D=tzU325W2Zp3DVpn-VmcQ@mail.gmail.com>
Subject: Re: [PATCH RFC fs/namespace] Make kern_unmount() use synchronize_rcu_expedited()
To:     paulmck@kernel.org
Cc:     Chris Mason <clm@fb.com>, Giuseppe Scrivano <gscrivan@redhat.com>,
        linux-kernel@vger.kernel.org,
        "riel@surriel.com" <riel@surriel.com>,
        "viro@zeniv.linux.org.uk" <viro@zeniv.linux.org.uk>
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> 3. https://lore.kernel.org/lkml/20220218183114.2867528-1-riel@surriel.com/
>         Refined queue_rcu_work() approach.
>
> #1 should work, but the resulting IPIs are not going to make the real-time
> guys happy.  #2 and #3 have been subject to reasonably heavy testing
> and did fix a very similar issue to the one that you are reporting,
> but last I knew there were doubts about the concurrency consequences.
>
> Could you please give at least #3 a shot and see if it helps you?
>

I have tried #3 and it works well with my testcases as far as I can see it.

Christoph