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From: Ingo Molnar <mingo@kernel.org>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Steve Muckle <steve.muckle@linaro.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Linux PM list <linux-pm@vger.kernel.org>,
	Juri Lelli <juri.lelli@arm.com>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Michael Turquette <mturquette@baylibre.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH v2 6/10] cpufreq: Support for fast frequency switching
Date: Sat, 5 Mar 2016 12:58:42 +0100	[thread overview]
Message-ID: <20160305115842.GB11846@gmail.com> (raw)
In-Reply-To: <CAJZ5v0gqnDR8BJ6JUKBB7-T8MAhNge9TPngZ9Crc45TRzm04vQ@mail.gmail.com>


* Rafael J. Wysocki <rafael@kernel.org> wrote:

> > Honestly I wonder if it's better to just try the "no notifiers with fast 
> > drivers" approach to start. The notifiers could always be added if platform 
> > owners complain that they absolutely require them.
> 
> Well, I'm not sure what happens if we start to fail notifier registrations.  It 
> may not be a well tested error code path. :-)

Yeah, so as a general principle 'struct notifier_block' as a really bad interface 
with poor and fragile semantics, and we are trying to get rid of them everywhere 
from core kernel code. For example Thomas Gleixner et al is working on eliminating 
them from the CPU hotplug code - which will get rid of most remaining notifier 
uses from the scheduler as well.

So please add explicit cpufreq driver callback functions instead, which can be 
filled in by a platform if needed. No notifiers!

Thanks,

	Ingo

  reply	other threads:[~2016-03-05 11:58 UTC|newest]

Thread overview: 158+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-02  1:56 [PATCH 0/6] cpufreq: schedutil governor Rafael J. Wysocki
2016-03-02  2:04 ` [PATCH 1/6] cpufreq: Reduce cpufreq_update_util() overhead a bit Rafael J. Wysocki
2016-03-03  5:48   ` Viresh Kumar
2016-03-03 11:47   ` Juri Lelli
2016-03-03 13:04     ` Peter Zijlstra
2016-03-02  2:05 ` [PATCH 2/6][Resend] cpufreq: acpi-cpufreq: Make read and write operations more efficient Rafael J. Wysocki
2016-03-02  2:08 ` [PATCH 3/6] cpufreq: governor: New data type for management part of dbs_data Rafael J. Wysocki
2016-03-03  5:53   ` Viresh Kumar
2016-03-03 19:26     ` Rafael J. Wysocki
2016-03-04  5:49       ` Viresh Kumar
2016-03-02  2:10 ` [PATCH 4/6] cpufreq: governor: Move abstract gov_tunables code to a seperate file Rafael J. Wysocki
2016-03-03  6:03   ` Viresh Kumar
2016-03-02  2:12 ` [PATCH 5/6] cpufreq: Support for fast frequency switching Rafael J. Wysocki
2016-03-03  6:00   ` Viresh Kumar
2016-03-04  2:15     ` Rafael J. Wysocki
2016-03-03 11:16   ` Peter Zijlstra
2016-03-03 20:56     ` Rafael J. Wysocki
2016-03-03 21:12       ` Peter Zijlstra
2016-03-03 11:18   ` Peter Zijlstra
2016-03-03 19:39     ` Rafael J. Wysocki
2016-03-02  2:27 ` [PATCH 6/6] cpufreq: schedutil: New governor based on scheduler utilization data Rafael J. Wysocki
2016-03-02 17:10   ` Vincent Guittot
2016-03-02 17:58     ` Rafael J. Wysocki
2016-03-02 22:49       ` Rafael J. Wysocki
2016-03-03 12:20         ` Peter Zijlstra
2016-03-03 12:32           ` Juri Lelli
2016-03-03 16:24           ` Rafael J. Wysocki
2016-03-03 16:37             ` Peter Zijlstra
2016-03-03 16:47               ` Peter Zijlstra
2016-03-04  1:14                 ` Rafael J. Wysocki
2016-03-03 16:55               ` Juri Lelli
2016-03-03 16:56                 ` Peter Zijlstra
2016-03-03 17:14                   ` Juri Lelli
2016-03-03 14:01         ` Vincent Guittot
2016-03-03 15:38           ` Peter Zijlstra
2016-03-03 16:28             ` Peter Zijlstra
2016-03-03 16:42               ` Peter Zijlstra
2016-03-03 17:28               ` Dietmar Eggemann
2016-03-03 18:26                 ` Peter Zijlstra
2016-03-03 19:14                   ` Dietmar Eggemann
2016-03-08 13:09                   ` Peter Zijlstra
2016-03-03 18:58               ` Rafael J. Wysocki
2016-03-03 13:07       ` Vincent Guittot
2016-03-03 20:06         ` Steve Muckle
2016-03-03 20:20           ` Rafael J. Wysocki
2016-03-03 21:37             ` Steve Muckle
2016-03-07  2:41               ` Rafael J. Wysocki
2016-03-08 11:27                 ` Peter Zijlstra
2016-03-08 18:00                   ` Rafael J. Wysocki
2016-03-08 19:26                     ` Peter Zijlstra
2016-03-08 20:05                       ` Rafael J. Wysocki
2016-03-09 10:15                         ` Juri Lelli
2016-03-09 23:41                           ` Rafael J. Wysocki
2016-03-10  4:30                             ` Juri Lelli
2016-03-10 21:01                               ` Rafael J. Wysocki
2016-03-10 23:19                             ` Michael Turquette
2016-03-09 16:39                         ` Peter Zijlstra
2016-03-09 23:28                           ` Rafael J. Wysocki
2016-03-10  3:44                             ` Vincent Guittot
2016-03-10 10:07                               ` Peter Zijlstra
2016-03-10 10:26                                 ` Vincent Guittot
     [not found]                                 ` <CAKfTPtCbjgbJn+68NJPCnmPFtcHD0wGmZRYaw37zSqPXNpo_Uw@mail.gmail.com>
2016-03-10 10:30                                   ` Peter Zijlstra
2016-03-10 10:56                                     ` Peter Zijlstra
2016-03-10 22:28                                       ` Rafael J. Wysocki
2016-03-10  8:43                             ` Peter Zijlstra
2016-03-04  2:56 ` [PATCH v2 0/10] cpufreq: schedutil governor Rafael J. Wysocki
2016-03-04  2:58   ` [PATCH v2 1/10] cpufreq: Reduce cpufreq_update_util() overhead a bit Rafael J. Wysocki
2016-03-09 12:39     ` Peter Zijlstra
2016-03-09 14:17       ` Rafael J. Wysocki
2016-03-09 15:29         ` Peter Zijlstra
2016-03-09 21:35           ` Rafael J. Wysocki
2016-03-10  9:19             ` Peter Zijlstra
2016-03-04  2:59   ` [PATCH v2 2/10][Resend] cpufreq: acpi-cpufreq: Make read and write operations more efficient Rafael J. Wysocki
2016-03-04  3:01   ` [PATCH v2 3/10] cpufreq: governor: New data type for management part of dbs_data Rafael J. Wysocki
2016-03-04  5:52     ` Viresh Kumar
2016-03-04  3:03   ` [PATCH v2 4/10] cpufreq: governor: Move abstract gov_attr_set code to seperate file Rafael J. Wysocki
2016-03-04  5:52     ` Viresh Kumar
2016-03-04  3:05   ` [PATCH v2 5/10] cpufreq: Move governor attribute set headers to cpufreq.h Rafael J. Wysocki
2016-03-04  5:53     ` Viresh Kumar
2016-03-04  3:07   ` [PATCH v2 6/10] cpufreq: Support for fast frequency switching Rafael J. Wysocki
2016-03-04 22:18     ` Steve Muckle
2016-03-04 22:32       ` Rafael J. Wysocki
2016-03-04 22:40         ` Rafael J. Wysocki
2016-03-04 23:18           ` Rafael J. Wysocki
2016-03-04 23:56             ` Steve Muckle
2016-03-05  0:18               ` Rafael J. Wysocki
2016-03-05 11:58                 ` Ingo Molnar [this message]
2016-03-05 16:49             ` Peter Zijlstra
2016-03-06  2:17               ` Rafael J. Wysocki
2016-03-07  8:00                 ` Peter Zijlstra
2016-03-07 13:15                   ` Rafael J. Wysocki
2016-03-07 13:32                     ` Peter Zijlstra
2016-03-07 13:42                       ` Rafael J. Wysocki
2016-03-04 22:58         ` Rafael J. Wysocki
2016-03-04 23:59           ` Steve Muckle
2016-03-04  3:12   ` [PATCH v2 7/10] cpufreq: Rework the scheduler hooks for triggering updates Rafael J. Wysocki
2016-03-04  3:14   ` [PATCH v2 8/10] cpufreq: Move scheduler-related code to the sched directory Rafael J. Wysocki
2016-03-04  3:18   ` [PATCH v2 9/10] cpufreq: sched: Re-introduce cpufreq_update_util() Rafael J. Wysocki
2016-03-04 10:50     ` Juri Lelli
2016-03-04 12:58       ` Rafael J. Wysocki
2016-03-04 13:30     ` [PATCH v3 " Rafael J. Wysocki
2016-03-04 21:21       ` Steve Muckle
2016-03-04 21:27         ` Rafael J. Wysocki
2016-03-04 21:36           ` Rafael J. Wysocki
2016-03-04  3:35   ` [PATCH v2 10/10] cpufreq: schedutil: New governor based on scheduler utilization data Rafael J. Wysocki
2016-03-04 11:26     ` Juri Lelli
2016-03-04 13:19       ` Rafael J. Wysocki
2016-03-04 15:56       ` Srinivas Pandruvada
2016-03-08  2:23   ` [PATCH v3 0/7] cpufreq: schedutil governor Rafael J. Wysocki
2016-03-08  2:25     ` [PATCH v3 1/7][Resend] cpufreq: Rework the scheduler hooks for triggering updates Rafael J. Wysocki
2016-03-09 13:41       ` Peter Zijlstra
2016-03-09 14:02         ` Rafael J. Wysocki
2016-03-08  2:26     ` [PATCH v3 2/7][Resend] cpufreq: Move scheduler-related code to the sched directory Rafael J. Wysocki
2016-03-08  2:28     ` [PATCH v3 3/7][Resend] cpufreq: governor: New data type for management part of dbs_data Rafael J. Wysocki
2016-03-08  2:29     ` [PATCH v3 4/7][Resend] cpufreq: governor: Move abstract gov_attr_set code to seperate file Rafael J. Wysocki
2016-03-08  2:38     ` [PATCH v3 5/7] cpufreq: Support for fast frequency switching Rafael J. Wysocki
2016-03-08  2:41     ` [PATCH v3 6/7] cpufreq: sched: Re-introduce cpufreq_update_util() Rafael J. Wysocki
2016-03-08  2:50     ` [PATCH v3 7/7] cpufreq: schedutil: New governor based on scheduler utilization data Rafael J. Wysocki
2016-03-16 14:41     ` [PATCH v4 0/7] cpufreq: schedutil governor Rafael J. Wysocki
2016-03-16 14:43       ` [PATCH v4 1/7] cpufreq: sched: Helpers to add and remove update_util hooks Rafael J. Wysocki
2016-03-16 14:44       ` [PATCH v4 2/7] cpufreq: governor: New data type for management part of dbs_data Rafael J. Wysocki
2016-03-16 14:45       ` [PATCH v4 3/7] cpufreq: governor: Move abstract gov_attr_set code to seperate file Rafael J. Wysocki
2016-03-16 14:46       ` [PATCH v4 4/7] cpufreq: Move governor attribute set headers to cpufreq.h Rafael J. Wysocki
2016-03-16 14:47       ` [PATCH v4 5/7] cpufreq: Move governor symbols " Rafael J. Wysocki
2016-03-16 14:52       ` [PATCH v4 6/7] cpufreq: Support for fast frequency switching Rafael J. Wysocki
2016-03-16 15:35         ` Peter Zijlstra
2016-03-16 16:58           ` Rafael J. Wysocki
2016-03-16 15:43         ` Peter Zijlstra
2016-03-16 16:58           ` Rafael J. Wysocki
2016-03-16 14:59       ` [PATCH v4 7/7] cpufreq: schedutil: New governor based on scheduler utilization data Rafael J. Wysocki
2016-03-16 17:35         ` Peter Zijlstra
2016-03-16 21:42           ` Rafael J. Wysocki
2016-03-16 17:36         ` Peter Zijlstra
2016-03-16 21:34           ` Rafael J. Wysocki
2016-03-16 17:52         ` Peter Zijlstra
2016-03-16 21:38           ` Rafael J. Wysocki
2016-03-16 22:39             ` Peter Zijlstra
2016-03-16 17:53         ` Peter Zijlstra
2016-03-16 21:48           ` Rafael J. Wysocki
2016-03-16 18:14         ` Peter Zijlstra
2016-03-16 21:38           ` Rafael J. Wysocki
2016-03-16 22:40             ` Peter Zijlstra
2016-03-16 22:53               ` Rafael J. Wysocki
2016-03-16 15:27       ` [PATCH v4 0/7] cpufreq: schedutil governor Peter Zijlstra
2016-03-16 16:20         ` Rafael J. Wysocki
2016-03-16 23:51       ` [PATCH v5 6/7][Update] cpufreq: Support for fast frequency switching Rafael J. Wysocki
2016-03-17 11:35         ` Juri Lelli
2016-03-17 11:40           ` Peter Zijlstra
2016-03-17 11:48             ` Juri Lelli
2016-03-17 12:53               ` Rafael J. Wysocki
2016-03-17  0:01       ` [PATCH v5 7/7][Update] cpufreq: schedutil: New governor based on scheduler utilization data Rafael J. Wysocki
2016-03-17 11:30         ` Juri Lelli
2016-03-17 12:54           ` Rafael J. Wysocki
2016-03-17 11:36         ` Peter Zijlstra
2016-03-17 12:54           ` Rafael J. Wysocki
2016-03-17 15:54       ` [PATCH v6 6/7][Update] cpufreq: Support for fast frequency switching Rafael J. Wysocki
2016-03-17 16:01       ` [PATCH v6 7/7][Update] cpufreq: schedutil: New governor based on scheduler utilization data Rafael J. Wysocki
2016-03-18 12:34         ` Patrick Bellasi

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