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From:   Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To:     nsaenzju@redhat.com
Cc:     Peter Zijlstra <peterz@infradead.org>, akpm@linux-foundation.org,
        frederic@kernel.org, linux-kernel@vger.kernel.org,
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        williams@redhat.com, anna-maria@linutronix.de,
        linux-rt-users@vger.kernel.org
Subject: Re: [PATCH 2/6] mm/swap: Introduce alternative per-cpu LRU cache
 locking
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References: <20210921161323.607817-1-nsaenzju@redhat.com>
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On 2021-09-22 10:47:07 [+0200], nsaenzju@redhat.com wrote:
> > *why* use migrate_disable(), that's horrible!
> 
> I was trying to be mindful of RT. They don't appreciate people taking spinlocks
> just after having disabled preemption.
> 
> I think getting local_lock(&locks->local) is my only option then. But it adds
> an extra redundant spinlock in the RT+NOHZ_FULL case.

spin_lock() does not disable preemption on PREEMPT_RT. You don't
disables preemption on purpose or did I miss that?

Sebastian