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Date:   Tue, 25 May 2021 16:16:55 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Vlastimil Babka <vbabka@suse.cz>
Cc:     Yejune Deng <yejune.deng@gmail.com>, cl@linux.com,
        penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Thomas Gleixner <tglx@linutronix.de>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Yejune Deng <yejunedeng@gmail.com>
Subject: Re: [PATCH 2/2] mm: slub: use DEFINE_RAW_SPINLOCK init
 object_map_lock
Message-Id: <20210525161655.bd9f91e9c29758142eb955e2@linux-foundation.org>
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References: <1621938235-11947-1-git-send-email-yejunedeng@gmail.com>
        <1621938235-11947-2-git-send-email-yejunedeng@gmail.com>
        <427f87d6-b506-a225-1887-cf8c13d99634@suse.cz>
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On Tue, 25 May 2021 12:46:35 +0200 Vlastimil Babka <vbabka@suse.cz> wrote:

> On 5/25/21 12:23 PM, Yejune Deng wrote:
> > Use DEFINE_RAW_SPINLOCK instead of DEFINE_SPINLOCK object_map_lock
> > that won't be preempted on mainline and PREEMPT_RT kernels.
> > 
> > Signed-off-by: Yejune Deng <yejunedeng@gmail.com>
> 
> RT tree also has such patch, with IMHO more thorough description:

Yes please, a more thorough decription is needed.  The description
provided with this patch could be applied to every spinlock in the
kernel!