From: Nicolas Saenz Julienne <nsaenzju@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>, linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, Minchan Kim <minchan@kernel.org>,
Matthew Wilcox <willy@infradead.org>,
Mel Gorman <mgorman@techsingularity.net>,
Juri Lelli <juril@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
"Paul E. McKenney" <paulmck@kernel.org>
Subject: Re: [patch 1/2] mm: protect local lock sections with rcu_read_lock (on RT)
Date: Tue, 22 Feb 2022 16:21:26 +0100 [thread overview]
Message-ID: <5f96c7e306546af4604cfaddb895a089811cb99b.camel@redhat.com> (raw)
In-Reply-To: <20220222144907.023121407@redhat.com>
On Tue, 2022-02-22 at 11:47 -0300, Marcelo Tosatti wrote:
> For the per-CPU LRU page vectors, augment the local lock protected
> code sections with rcu_read_lock.
>
> This makes it possible to replace the queueing of work items on all
> CPUs by synchronize_rcu (which is necessary to run FIFO:1 applications
> uninterrupted on isolated CPUs).
I don't think this is needed. In RT local_locks use a spinlock. See
kernel/locking/spinlock_rt.c:
"The RT [spinlock] substitutions explicitly disable migration and take
rcu_read_lock() across the lock held section."
Regards,
--
Nicolás Sáenz
next prev parent reply other threads:[~2022-02-22 15:21 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-22 14:47 [patch 0/2] replace work queue synchronization with synchronize_rcu Marcelo Tosatti
2022-02-22 14:47 ` [patch 1/2] mm: protect local lock sections with rcu_read_lock (on RT) Marcelo Tosatti
2022-02-22 15:21 ` Nicolas Saenz Julienne [this message]
2022-02-22 15:51 ` Marcelo Tosatti
2022-02-22 16:16 ` Nicolas Saenz Julienne
2022-02-22 14:47 ` [patch 2/2] mm: lru_cache_disable: replace work queue synchronization with synchronize_rcu Marcelo Tosatti
2022-02-22 15:53 ` Nicolas Saenz Julienne
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