linux-kernel - Re: [PATCH v3 1/5] locking/qspinlock: Make arch_mcs_spin_unlock

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Message-ID: <20190716102314.GO3419@hirez.programming.kicks-ass.net>
Date:   Tue, 16 Jul 2019 12:23:14 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Alex Kogan <alex.kogan@...cle.com>
Cc:     linux@...linux.org.uk, mingo@...hat.com, will.deacon@....com,
        arnd@...db.de, longman@...hat.com, linux-arch@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        tglx@...utronix.de, bp@...en8.de, hpa@...or.com, x86@...nel.org,
        guohanjun@...wei.com, jglauber@...vell.com,
        steven.sistare@...cle.com, daniel.m.jordan@...cle.com,
        dave.dice@...cle.com, rahul.x.yadav@...cle.com
Subject: Re: [PATCH v3 1/5] locking/qspinlock: Make
 arch_mcs_spin_unlock_contended more generic

On Mon, Jul 15, 2019 at 03:25:32PM -0400, Alex Kogan wrote:

> diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c
> index e14b32c69639..961781624638 100644
> --- a/kernel/locking/qspinlock.c
> +++ b/kernel/locking/qspinlock.c
> @@ -558,7 +558,7 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val)
>  	if (!next)
>  		next = smp_cond_load_relaxed(&node->next, (VAL));
>  
> -	arch_mcs_spin_unlock_contended(&next->locked);
> +	arch_mcs_spin_unlock_contended(&next->locked, 1);
>  	pv_kick_node(lock, next);

My problem with this patch is that the above reads really daft. Should
we rename the whole function? arch_mcs_pass_lock() perhaps?