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From: Nicolas Pitre <nicolas.pitre@linaro.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Sudeep Holla <sudeep.holla@arm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Linux PM list <linux-pm@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>
Subject: Re: [PATCH][Fix] cpuidle: Run tick_broadcast_exit() with disabled interrupts
Date: Thu, 30 Apr 2015 16:12:46 -0400 (EDT)	[thread overview]
Message-ID: <alpine.LFD.2.11.1504301602180.1582@knanqh.ubzr> (raw)
In-Reply-To: <2872649.RClMYKns0i@vostro.rjw.lan>

On Wed, 29 Apr 2015, Rafael J. Wysocki wrote:

> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> Commit 335f49196fd6 (sched/idle: Use explicit broadcast oneshot
> control function) replaced clockevents_notify() invocations in
> cpuidle_idle_call() with direct calls to tick_broadcast_enter()
> and tick_broadcast_exit(), but it overlooked the fact that
> interrupts were already enabled before calling the latter which
> led to functional breakage on systems using idle states with the
> CPUIDLE_FLAG_TIMER_STOP flag set.
> 
> Fix that by moving the invocations of tick_broadcast_enter()
> and tick_broadcast_exit() down into cpuidle_enter_state() where
> interrupts are still disabled when tick_broadcast_exit() is
> called.  Also ensure that interrupts will be disabled before
> running tick_broadcast_exit() even if they have been enabled by
> the idle state's ->enter callback.  Trigger a WARN_ON_ONCE() in
> that case, as we generally don't want that to happen for states
> with CPUIDLE_FLAG_TIMER_STOP set.

Incidentally I was debugging this issue as well when I saw this thread.

And it turns out that I did report this issue 2 months ago:
http://article.gmane.org/gmane.linux.kernel/1892049
What happened?

> Fixes: 335f49196fd6 (sched/idle: Use explicit broadcast oneshot control function)
> Reported-and-tested-by: Linus Walleij <linus.walleij@linaro.org>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Tested-by: Nicolas Pitre <nico@linaro.org>

> ---
> 
> Thanks for the testing and ACKs, here it goes again with all tags and
> a changelog.
> 
> If anything is missing/incorrect, please let me know ASAP as I'm going to
> push this to Linus in a couple of days.
> 
> ---
>  drivers/cpuidle/cpuidle.c |   16 ++++++++++++++++
>  kernel/sched/idle.c       |   16 ++--------------
>  2 files changed, 18 insertions(+), 14 deletions(-)
> 
> Index: linux-pm/kernel/sched/idle.c
> ===================================================================
> --- linux-pm.orig/kernel/sched/idle.c
> +++ linux-pm/kernel/sched/idle.c
> @@ -81,7 +81,6 @@ static void cpuidle_idle_call(void)
>  	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
>  	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
>  	int next_state, entered_state;
> -	unsigned int broadcast;
>  	bool reflect;
>  
>  	/*
> @@ -150,17 +149,6 @@ static void cpuidle_idle_call(void)
>  		goto exit_idle;
>  	}
>  
> -	broadcast = drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP;
> -
> -	/*
> -	 * Tell the time framework to switch to a broadcast timer
> -	 * because our local timer will be shutdown. If a local timer
> -	 * is used from another cpu as a broadcast timer, this call may
> -	 * fail if it is not available
> -	 */
> -	if (broadcast && tick_broadcast_enter())
> -		goto use_default;
> -
>  	/* Take note of the planned idle state. */
>  	idle_set_state(this_rq(), &drv->states[next_state]);
>  
> @@ -174,8 +162,8 @@ static void cpuidle_idle_call(void)
>  	/* The cpu is no longer idle or about to enter idle. */
>  	idle_set_state(this_rq(), NULL);
>  
> -	if (broadcast)
> -		tick_broadcast_exit();
> +	if (entered_state == -EBUSY)
> +		goto use_default;
>  
>  	/*
>  	 * Give the governor an opportunity to reflect on the outcome
> Index: linux-pm/drivers/cpuidle/cpuidle.c
> ===================================================================
> --- linux-pm.orig/drivers/cpuidle/cpuidle.c
> +++ linux-pm/drivers/cpuidle/cpuidle.c
> @@ -158,9 +158,18 @@ int cpuidle_enter_state(struct cpuidle_d
>  	int entered_state;
>  
>  	struct cpuidle_state *target_state = &drv->states[index];
> +	bool broadcast = !!(target_state->flags & CPUIDLE_FLAG_TIMER_STOP);
>  	ktime_t time_start, time_end;
>  	s64 diff;
>  
> +	/*
> +	 * Tell the time framework to switch to a broadcast timer because our
> +	 * local timer will be shut down.  If a local timer is used from another
> +	 * CPU as a broadcast timer, this call may fail if it is not available.
> +	 */
> +	if (broadcast && tick_broadcast_enter())
> +		return -EBUSY;
> +
>  	trace_cpu_idle_rcuidle(index, dev->cpu);
>  	time_start = ktime_get();
>  
> @@ -169,6 +178,13 @@ int cpuidle_enter_state(struct cpuidle_d
>  	time_end = ktime_get();
>  	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
>  
> +	if (broadcast) {
> +		if (WARN_ON_ONCE(!irqs_disabled()))
> +			local_irq_disable();
> +
> +		tick_broadcast_exit();
> +	}
> +
>  	if (!cpuidle_state_is_coupled(dev, drv, entered_state))
>  		local_irq_enable();
>  
> 
> --
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> Please read the FAQ at  http://www.tux.org/lkml/
> 
> 

  parent reply	other threads:[~2015-04-30 20:12 UTC|newest]

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-01 22:02 [PATCH 00/20] clockevents_notify() removal Rafael J. Wysocki
2015-04-01 22:03 ` [PATCH 01/20] clockevents: Provide explicit broadcast control functions Rafael J. Wysocki
2015-04-01 22:04 ` [PATCH 02/20] x86, amd_idle: Use explicit broadcast control function Rafael J. Wysocki
2015-04-01 22:05 ` [PATCH 03/20] ACPI / PAD: " Rafael J. Wysocki
2015-04-01 22:06 ` [PATCH 04/20] ACPI / processor: " Rafael J. Wysocki
2015-04-01 22:07 ` [PATCH 05/20] cpuidle: " Rafael J. Wysocki
2015-04-01 22:09 ` [PATCH 06/20] intel_idle: " Rafael J. Wysocki
2015-04-01 22:10 ` [PATCH 07/20] ARM: OMAP: " Rafael J. Wysocki
2015-04-01 22:11 ` [PATCH 08/20] clockevents: Remove the broadcast control leftovers Rafael J. Wysocki
2015-04-01 22:13 ` [PATCH 09/20] clockevents: Provide explicit broadcast oneshot control functions Rafael J. Wysocki
2015-04-01 22:15 ` [PATCH 10/20] x86, amd_idle: Use " Rafael J. Wysocki
2015-04-01 22:16 ` [PATCH 11/20] ACPI / PAD: Use explicit broadcast oneshot control function Rafael J. Wysocki
2015-04-01 22:17 ` [PATCH 12/20] ACPI / processor: Use explicit broadcast controll function Rafael J. Wysocki
2015-04-01 22:20 ` [PATCH 13/20] intel_idle: Use explicit broadcast oneshot control function Rafael J. Wysocki
2015-04-01 22:20 ` [PATCH 14/20] ARM: OMAP: " Rafael J. Wysocki
2015-04-01 22:21 ` [PATCH 15/20] ARM: tegra: " Rafael J. Wysocki
2015-04-01 22:22 ` [PATCH 16/20] sched/idle: " Rafael J. Wysocki
2015-04-28 10:11   ` Linus Walleij
2015-04-28 10:17     ` Sudeep Holla
2015-04-28 10:34     ` Daniel Lezcano
2015-04-28 10:42       ` Sudeep Holla
2015-04-28 12:19         ` Rafael J. Wysocki
2015-04-28 12:37           ` Linus Walleij
2015-04-28 13:31             ` Rafael J. Wysocki
2015-04-28 13:37               ` Rafael J. Wysocki
2015-04-28 14:14                 ` Rafael J. Wysocki
2015-04-28 13:58                   ` Sudeep Holla
2015-04-29  0:50                     ` Rafael J. Wysocki
2015-04-29  1:04                       ` Rafael J. Wysocki
2015-04-29  7:10                         ` Linus Walleij
2015-04-29  8:57                         ` Peter Zijlstra
2015-04-29  9:44                         ` Daniel Lezcano
2015-04-29  9:50                         ` Sudeep Holla
2015-04-29 14:07                           ` [PATCH][Fix] cpuidle: Run tick_broadcast_exit() with disabled interrupts Rafael J. Wysocki
2015-04-30  3:47                             ` Preeti U Murthy
2015-04-30 20:12                             ` Nicolas Pitre [this message]
2015-04-30 22:10                               ` Rafael J. Wysocki
2015-04-30  3:45                         ` [PATCH 16/20] sched/idle: Use explicit broadcast oneshot control function Preeti U Murthy
2015-04-28 13:04           ` Sudeep Holla
2015-04-01 22:23 ` [PATCH 17/20] clockevents: Remove broadcast oneshot control leftovers Rafael J. Wysocki
2015-04-01 22:24 ` [PATCH 18/20] clockevents: Make tick handover explicit Rafael J. Wysocki
2015-04-01 22:25 ` [PATCH 19/20] clockevents: Cleanup dead cpu explicitely Rafael J. Wysocki
2015-04-01 22:26 ` [PATCH 20/20] timekeeping: Get rid of stale comment Rafael J. Wysocki
2015-04-01 23:57   ` John Stultz
2015-04-02 12:39 ` [PATCH 00/20] clockevents_notify() removal Ingo Molnar
2015-04-02 22:19   ` Rafael J. Wysocki
2015-04-02 23:45     ` [v2][PATCH 00/21] " Rafael J. Wysocki
2015-04-02 23:46       ` [v2][PATCH 01/21] ACPI / PAD: Remove the local APIC nonsense Rafael J. Wysocki
2015-04-03  8:21         ` [tip:timers/core] ACPI/PAD: " tip-bot for Thomas Gleixner
2015-04-03  0:01       ` [v2][PATCH 02/21] clockevents: Provide explicit broadcast control functions Rafael J. Wysocki
2015-04-03  8:21         ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-03  0:01       ` [v2][PATCH 03/21] x86, amd_idle: Use explicit broadcast control function Rafael J. Wysocki
2015-04-03  8:22         ` [tip:timers/core] x86/amd/idle, clockevents: " tip-bot for Thomas Gleixner
2015-04-03  0:01       ` [v2][PATCH 04/21] ACPI / PAD: " Rafael J. Wysocki
2015-04-03  8:22         ` [tip:timers/core] ACPI/PAD: " tip-bot for Thomas Gleixner
2015-04-03  0:02       ` [v2][PATCH 05/21] ACPI / processor: " Rafael J. Wysocki
2015-04-03  8:22         ` [tip:timers/core] ACPI/processor: " tip-bot for Thomas Gleixner
2015-04-03  0:02       ` [v2][PATCH 06/21] cpuidle: " Rafael J. Wysocki
2015-04-03  8:23         ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-03  0:02       ` [v2][PATCH 07/21] intel_idle: " Rafael J. Wysocki
2015-04-03  8:23         ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-03  0:02       ` [v2][PATCH 08/21] ARM: OMAP: " Rafael J. Wysocki
2015-04-03  8:23         ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-03  0:03       ` [v2][PATCH 09/21] clockevents: Remove the broadcast control leftovers Rafael J. Wysocki
2015-04-03  8:23         ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-03  0:05       ` [v2][PATCH 10/21] clockevents: Provide explicit broadcast oneshot control functions Rafael J. Wysocki
2015-04-03  8:24         ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-03  0:05       ` [v2][PATCH 11/21] x86, amd_idle: Use " Rafael J. Wysocki
2015-04-03  8:24         ` [tip:timers/core] x86/amd/idle, clockevents: " tip-bot for Thomas Gleixner
2015-04-03  0:06       ` [v2][PATCH 12/21] ACPI / PAD: Use explicit broadcast oneshot control function Rafael J. Wysocki
2015-04-03  8:24         ` [tip:timers/core] ACPI/PAD: " tip-bot for Thomas Gleixner
2015-04-03  0:12       ` [v2][PATCH 13/21] ACPI / processor: Use explicit broadcast controll function Rafael J. Wysocki
2015-04-03  8:25         ` [tip:timers/core] ACPI/idle: Use explicit broadcast control function tip-bot for Thomas Gleixner
2015-04-03  0:14       ` [v2][PATCH 14/21] intel_idle: Use explicit broadcast oneshot " Rafael J. Wysocki
2015-04-03  8:25         ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-03  0:31       ` [v2][PATCH 15/21] ARM: OMAP: " Rafael J. Wysocki
2015-04-03  8:25         ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-03  0:32       ` [v2][PATCH 16/21] ARM: tegra: " Rafael J. Wysocki
2015-04-03  8:25         ` [tip:timers/core] ARM: Tegra: " tip-bot for Thomas Gleixner
2015-04-03  0:34       ` [v2][PATCH 17/21] sched/idle: " Rafael J. Wysocki
2015-04-03  8:26         ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-03  0:36       ` [v2][PATCH 18/21] clockevents: Remove broadcast oneshot control leftovers Rafael J. Wysocki
2015-04-03  8:26         ` [tip:timers/core] " tip-bot for Rafael J. Wysocki
2015-04-03  0:37       ` [v2][PATCH 19/21] clockevents: Make tick handover explicit Rafael J. Wysocki
2015-04-03  8:26         ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-03  0:38       ` [v2][PATCH 20/21] clockevents: Cleanup dead cpu explicitely Rafael J. Wysocki
2015-04-03  8:26         ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-03  0:39       ` [v2][PATCH 21/21] timekeeping: Get rid of stale comment Rafael J. Wysocki
2015-04-03  8:27         ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-03  6:45       ` [v2][PATCH 00/21] clockevents_notify() removal Ingo Molnar

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