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From: Ingo Molnar <mingo@kernel.org>
To: Borislav Petkov <bp@alien8.de>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	x86-ml <x86@kernel.org>, lkml <linux-kernel@vger.kernel.org>,
	tiwai@suse.de, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: irq 16: nobody cared
Date: Mon, 22 Apr 2013 10:01:36 +0200	[thread overview]
Message-ID: <20130422080136.GA7080@gmail.com> (raw)
In-Reply-To: <20130421221242.GB4593@pd.tnic>


* Borislav Petkov <bp@alien8.de> wrote:

> From 3c155e9a22036839c09d98a4acbc7e17a5a3783c Mon Sep 17 00:00:00 2001
> From: Borislav Petkov <bp@suse.de>
> Date: Sun, 21 Apr 2013 23:56:15 +0200
> Subject: [PATCH] RCU: Expedite grace periods during suspend/resume
> 
> Paul says CONFIG_RCU_FAST_NO_HZ can increase grace-period durations by a
> factor of four. This, in turn, can change timings during suspend and can
> delay interrupts handling, leading to "IRQ XX: nobody cared" splats and
> the machine disabling those interrupt lines for no sensible reason.
> 
> Thus, we want to temporarily switch to expedited grace periods when
> suspending the box and return to normal settings when resuming. This
> patch does exactly that.

Hm, this really smells like a workaround: treating the symptom, not the 
cause.

How can an increase in grace-periods break drivers and suspend? Do we 
understand exactly what happens there? If we do, can we fix that instead 
of tweaking the RCU timeouts?

Thanks,

	Ingo

  reply	other threads:[~2013-04-22  8:01 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-20 18:53 irq 16: nobody cared Borislav Petkov
2013-04-20 23:52 ` Paul E. McKenney
2013-04-21 10:34   ` Borislav Petkov
2013-04-21 16:30     ` Paul E. McKenney
2013-04-21 16:56       ` Borislav Petkov
2013-04-21 18:10         ` Borislav Petkov
2013-04-21 18:56           ` Paul E. McKenney
2013-04-21 19:06             ` Borislav Petkov
2013-04-21 20:34               ` Paul E. McKenney
2013-04-21 20:51                 ` Borislav Petkov
2013-04-21 21:42                   ` Borislav Petkov
2013-04-21 22:00                     ` Paul E. McKenney
2013-04-21 22:12                       ` Borislav Petkov
2013-04-22  8:01                         ` Ingo Molnar [this message]
2013-04-22  9:18                           ` Borislav Petkov
2013-04-22 13:16                             ` Paul E. McKenney
2013-04-21 18:47         ` Paul E. McKenney
2013-04-22  8:32       ` Takashi Iwai
2013-04-22  9:13         ` Borislav Petkov
2013-04-22  9:19           ` Takashi Iwai
2013-04-22 10:06             ` Borislav Petkov
2013-04-22 11:33               ` Takashi Iwai
2013-04-22 13:56                 ` Borislav Petkov
2013-04-22 12:56             ` Thomas Gleixner
2013-04-22 14:23               ` Borislav Petkov
2013-04-22 14:44                 ` Paul E. McKenney
2013-04-22 21:33                   ` Borislav Petkov
2013-04-22 22:07                     ` Paul E. McKenney
2013-04-23 14:10                     ` Thomas Gleixner
2013-04-23 14:34                       ` Borislav Petkov
2013-04-23 15:01                       ` Paul E. McKenney

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