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From: Peter Zijlstra <peterz@infradead.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: minyard@acm.org, linux-rt-users@vger.kernel.org,
	Corey Minyard <cminyard@mvista.com>,
	linux-kernel@vger.kernel.org, tglx@linutronix.de,
	Steven Rostedt <rostedt@goodmis.org>,
	Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH RT v2] Fix a lockup in wait_for_completion() and friends
Date: Tue, 14 May 2019 13:35:38 +0200	[thread overview]
Message-ID: <20190514113538.GL2589@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190514091219.nesriqe7qplk3476@linutronix.de>

On Tue, May 14, 2019 at 11:12:19AM +0200, Sebastian Andrzej Siewior wrote:
> On 2019-05-14 10:43:56 [+0200], Peter Zijlstra wrote:
> > Now.. that will fix it, but I think it is also wrong.
> > 
> > The problem being that it violates FIFO, something that might be more
> > important on -RT than elsewhere.
> 
> Wouldn't -RT be more about waking the task with the highest priority
> instead the one that waited the longest?

Possibly, but that's a far larger patch. Also, even with that
completions do not avoid inversions and thus don't really make nice RT
primitives anyway.

  reply	other threads:[~2019-05-14 11:35 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-08 20:57 [PATCH v2] Fix a lockup in wait_for_completion() and friends minyard
2019-05-09 16:19 ` [PATCH RT " Sebastian Andrzej Siewior
2019-05-09 17:46   ` Corey Minyard
2019-05-14  8:43   ` Peter Zijlstra
2019-05-14  9:12     ` Sebastian Andrzej Siewior
2019-05-14 11:35       ` Peter Zijlstra [this message]
2019-05-14 15:25         ` Sebastian Andrzej Siewior
2019-05-14 12:13       ` Corey Minyard
2019-05-14 15:36         ` Sebastian Andrzej Siewior
2019-05-15 16:22           ` Corey Minyard
2019-06-26 10:35   ` Peter Zijlstra
2019-05-09 19:33 minyard
2019-05-09 19:51 ` Steven Rostedt
2019-05-10 10:33 ` Sebastian Andrzej Siewior
2019-05-10 12:08   ` Corey Minyard
2019-05-10 12:26     ` Sebastian Andrzej Siewior
2019-06-29  1:49   ` Steven Rostedt
2019-07-01 19:09     ` Corey Minyard
2019-07-01 20:18       ` Steven Rostedt
2019-07-01 20:43         ` Corey Minyard
2019-07-01 21:06           ` Steven Rostedt
2019-07-01 21:13             ` Steven Rostedt
2019-07-01 21:28               ` Steven Rostedt
2019-07-01 21:34                 ` Corey Minyard
2019-07-02  7:04                 ` Kurt Kanzenbach
2019-07-02  8:35                   ` Sebastian Andrzej Siewior
2019-07-02 11:40                     ` Corey Minyard
2019-07-02 11:53                       ` Sebastian Andrzej Siewior

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