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Date:   Wed, 4 Aug 2021 18:22:31 +0200
From:   Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     Jens Axboe <axboe@kernel.dk>,
        Peter Zijlstra <peterz@infradead.org>,
        Daniel Wagner <wagi@monom.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-rt-users@vger.kernel.org
Subject: Re: [ANNOUNCE] v5.14-rc4-rt4
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On 2021-08-04 12:17:04 [-0400], Steven Rostedt wrote:
> Perhaps in this situation, we could open code it to:
> 
>   	if (stall_hash != -1U) {
> 		raw_spin_unlock(&wqe->lock);
> 
> 		/* On RT the spin_lock_irq() does not disable interrupts */
> 		if (IS_ENABLED(CONFIG_PREEMPT_RT))
> 			local_irq_enable();

no preemption happens here with NEED_RESCHED set.

>  		io_wait_on_hash(wqe, stall_hash);
> 
> 		if (IS_ENABLED(CONFIG_PREEMPT_RT))
> 			local_irq_disable();
> 		raw_spin_lock(&wqe->lock);
>  	}
> 
> Note, I haven't looked at the rest of the code to know the ripple
> effect of this, but I'm just suggesting the idea.
> 

Sebastian