From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>, Jan Kara <jack@suse.cz>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
Waiman Long <longman@redhat.com>,
Boqun Feng <boqun.feng@gmail.com>,
Pierre Gondois <pierre.gondois@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Catalin Marinas <catalin.marinas@arm.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux-RT <linux-rt-users@vger.kernel.org>
Subject: Re: [PATCH] rtmutex: Add acquire semantics for rtmutex lock acquisition
Date: Fri, 2 Dec 2022 12:21:06 +0100 [thread overview]
Message-ID: <Y4nfopZfBxR4lJ6G@linutronix.de> (raw)
In-Reply-To: <20221202100223.6mevpbl7i6x5udfd@techsingularity.net>
On 2022-12-02 10:02:23 [+0000], Mel Gorman wrote:
> The lock owner is updated with an IRQ-safe raw spinlock held but the
> spin_unlock does not provide acquire semantics which are needed when
> acquiring a mutex. This patch adds the necessary acquire semantics for a
> lock operation when the lock owner is updated. It successfully completed
> 10 iterations of the dbench workload while the vanilla kernel fails on
> the first iteration.
I *think* it is
Fixes: 700318d1d7b38 ("locking/rtmutex: Use acquire/release semantics")
Before that, it did cmpxchg() which should be fine.
Regarding mark_rt_mutex_waiters(). Isn't acquire semantic required in
order for the lock-owner not perform the fastpath but go to the slowpath
instead?
Sebastian
next prev parent reply other threads:[~2022-12-02 11:21 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-02 10:02 [PATCH] rtmutex: Add acquire semantics for rtmutex lock acquisition Mel Gorman
2022-12-02 11:21 ` Sebastian Andrzej Siewior [this message]
2022-12-02 15:01 ` Mel Gorman
2022-12-06 11:43 ` Sebastian Andrzej Siewior
2022-12-16 10:31 ` Mel Gorman
2022-12-16 11:14 ` Will Deacon
2022-12-16 13:55 ` Mel Gorman
2022-12-16 15:58 ` Will Deacon
2022-12-16 16:20 ` Sebastian Andrzej Siewior
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