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From: Sudeep Holla <sudeep.holla@arm.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Daniel Lezcano <daniel.lezcano@linaro.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 16/20] sched/idle: Use explicit broadcast oneshot control function
Date: Wed, 29 Apr 2015 10:50:57 +0100	[thread overview]
Message-ID: <5540A981.6060209@arm.com> (raw)
In-Reply-To: <6185796.9I7OmaAAcQ@vostro.rjw.lan>

Hi Rafael,

On 29/04/15 02:04, Rafael J. Wysocki wrote:
> On Wednesday, April 29, 2015 02:50:22 AM Rafael J. Wysocki wrote:

[...]

>>
>> Below is the patch I came up with in the meantime.
>>
>> This moves the "switch to broadcast" timer logic into
>> cpuidle_enter_state() which allows tick_broadcast_exit() to be
>> called directly with interrupts disabled (as required), but
>> it also adds a fallback branch reflecting the 4.0 and earlier
>> behavior for idle states that enable interrupts on exit
>> from their ->enter callbacks.
>>
>> I'm not aware of any valid cases when CPUIDLE_FLAG_TIMER_STOP can be
>> set for such states, but people may try to add stuff like that in the
>> future, so it's better to catch that (hence the WARN_ON_ONCE) and do
>> our best to handle it gracefully anyway, IMO.
>>
>> The "if (entered_state == -EBUSY)" check is conservative.  It may
>> be better to do "if (entered_state < 0)" and fall back to the default
>> on all errors, but that's not what we do today (I guess the concern
>> would be "what if the state ->enter returns an error after entering
>> and exiting the idle state, in which case we may miss a wakeup event
>> if we fall back to the default").
>
> Actually, if my understanding of things is correct (the local clock event
> device cannot go away from under code executed with interrupts disabled
> on the local CPU), the simplified one below should be sufficient.
>

Tested-by: Sudeep Holla <sudeep.holla@arm.com>

Regards,
Sudeep

  parent reply	other threads:[~2015-04-29  9:51 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 [this message]
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
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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