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From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: John Stultz <jstultz@google.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Joel Fernandes <joelaf@google.com>,
	Qais Yousef <qyousef@layalina.io>, Ingo Molnar <mingo@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Valentin Schneider <vschneid@redhat.com>,
	Ben Segall <bsegall@google.com>,
	Zimuzo Ezeozue <zezeozue@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, Connor O'Brien <connoro@google.com>
Subject: Re: [RESEND x3][PATCH v12 2/7] locking/mutex: Make mutex::wait_lock irq safe
Date: Thu, 10 Oct 2024 16:05:14 +0200	[thread overview]
Message-ID: <20241010140514.GJ17263@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20241010100045.321ca4de@gandalf.local.home>

On Thu, Oct 10, 2024 at 10:00:45AM -0400, Steven Rostedt wrote:
> On Wed,  9 Oct 2024 16:53:35 -0700
> John Stultz <jstultz@google.com> wrote:
> 
> > From: Juri Lelli <juri.lelli@redhat.com>
> > 
> > mutex::wait_lock might be nested under rq->lock.
> > 
> > Make it irq safe then.
> 
> Can you expand on this please?
> 
> If the mutex:wait_lock might be taken under an rq->lock, doesn't that mean
> a mutex was taken under rq->lock? Or is it something internal?

Very similar to what we do for rt_mutex during PI; we'll want to look at
mutex_owner during the block chain walk, and holding wait_lock ensures
objects persistence.


  reply	other threads:[~2024-10-10 14:05 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-09 23:53 [RESEND x3][PATCH v12 0/7] Preparatory changes for Proxy Execution v12 John Stultz
2024-10-09 23:53 ` [RESEND x3][PATCH v12 1/7] locking/mutex: Remove wakeups from under mutex::wait_lock John Stultz
2024-10-18  7:07   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2024-10-09 23:53 ` [RESEND x3][PATCH v12 2/7] locking/mutex: Make mutex::wait_lock irq safe John Stultz
2024-10-10 14:00   ` Steven Rostedt
2024-10-10 14:05     ` Peter Zijlstra [this message]
2024-10-11  2:26     ` John Stultz
2024-10-11  2:31       ` Steven Rostedt
2024-10-18  7:07   ` [tip: sched/core] " tip-bot2 for Juri Lelli
2024-10-09 23:53 ` [RESEND x3][PATCH v12 3/7] locking/mutex: Expose __mutex_owner() John Stultz
2024-10-18  7:07   ` [tip: sched/core] " tip-bot2 for Juri Lelli
2024-10-09 23:53 ` [RESEND x3][PATCH v12 4/7] sched: Add move_queued_task_locked helper John Stultz
2024-10-18  7:07   ` [tip: sched/core] " tip-bot2 for Connor O'Brien
2024-10-09 23:53 ` [RESEND x3][PATCH v12 5/7] sched: Consolidate pick_*_task to task_is_pushable helper John Stultz
2024-10-18  7:07   ` [tip: sched/core] " tip-bot2 for Connor O'Brien
2024-10-09 23:53 ` [RESEND x3][PATCH v12 6/7] sched: Split out __schedule() deactivate task logic into a helper John Stultz
2024-10-18  7:07   ` [tip: sched/core] " tip-bot2 for John Stultz
2024-10-09 23:53 ` [RESEND x3][PATCH v12 7/7] sched: Split scheduler and execution contexts John Stultz
2024-10-18  7:07   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra

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