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Date: Fri, 12 Jul 2024 16:52:47 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: John Stultz <jstultz@google.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Joel Fernandes <joelaf@google.com>,
	Qais Yousef <qyousef@layalina.io>, Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Valentin Schneider <vschneid@redhat.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>,
	Zimuzo Ezeozue <zezeozue@google.com>,
	Youssef Esmat <youssefesmat@google.com>,
	Mel Gorman <mgorman@suse.de>, Will Deacon <will@kernel.org>,
	Waiman Long <longman@redhat.com>, Boqun Feng <boqun.feng@gmail.com>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Metin Kaya <Metin.Kaya@arm.com>,
	Xuewen Yan <xuewen.yan94@gmail.com>,
	K Prateek Nayak <kprateek.nayak@amd.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Daniel Lezcano <daniel.lezcano@linaro.org>, kernel-team@android.com,
	Davidlohr Bueso <dave@stgolabs.net>
Subject: Re: [PATCH v11 1/7] locking/mutex: Remove wakeups from under
 mutex::wait_lock
Message-ID: <20240712145247.GL27299@noisy.programming.kicks-ass.net>
References: <20240709203213.799070-1-jstultz@google.com>
 <20240709203213.799070-2-jstultz@google.com>
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In-Reply-To: <20240709203213.799070-2-jstultz@google.com>

On Tue, Jul 09, 2024 at 01:31:44PM -0700, John Stultz wrote:
> @@ -405,8 +409,10 @@ ww_mutex_set_context_fastpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
>  	 * die or wound us.
>  	 */
>  	lock_wait_lock(&lock->base);
> -	__ww_mutex_check_waiters(&lock->base, ctx);
> +	__ww_mutex_check_waiters(&lock->base, ctx, &wake_q);

  preempt_disable()

>  	unlock_wait_lock(&lock->base);
> +
> +	wake_up_q(&wake_q);

  preempt_enable();

>  }
>  
>  static __always_inline int