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Date:   Wed, 29 Sep 2021 16:13:09 -0400 (EDT)
From:   Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Will Deacon <will@kernel.org>, paulmck <paulmck@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Segher Boessenkool <segher@kernel.crashing.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Alan Stern <stern@rowland.harvard.edu>,
        Andrea Parri <parri.andrea@gmail.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Nicholas Piggin <npiggin@gmail.com>,
        David Howells <dhowells@redhat.com>,
        j alglave <j.alglave@ucl.ac.uk>,
        luc maranget <luc.maranget@inria.fr>,
        akiyks <akiyks@gmail.com>,
        linux-toolchains <linux-toolchains@vger.kernel.org>,
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Subject: Re: [RFC PATCH] LKMM: Add ctrl_dep() macro for control dependency
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Thread-Topic: LKMM: Add ctrl_dep() macro for control dependency
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----- On Sep 29, 2021, at 3:50 PM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote:

[...]

> void fct(void)
> {
>    int x;
> 
>    if (refcount_dec_and_test()) {
>        var1 = 0;

in this example, this should be "var1 = 1;", so both legs are similar,
otherwise we end up with a dependency on the load.

Thanks,

Mathieu

>        return;
>    }
>    __smp_rmb();
>    var1 = 1;
> }
-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com