From: Kevin Hilman <khilman@kernel.org>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>,
ulf.hansson@linaro.org, linux-pm@vger.kernel.org,
daniel.lezcano@linaro.org, rjw@rjwysocki.net,
linux-kernel@vger.kernel.org, Lina Iyer <lina.iyer@linaro.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 3/4] irq: Allow multiple clients to register for irq affinity notification
Date: Fri, 26 Sep 2014 08:10:04 -0700 [thread overview]
Message-ID: <7hioka4dv7.fsf@deeprootsystems.com> (raw)
In-Reply-To: <20140926094003.GL5182@n2100.arm.linux.org.uk> (Russell King's message of "Fri, 26 Sep 2014 10:40:03 +0100")
Russell King - ARM Linux <linux@arm.linux.org.uk> writes:
> On Fri, Sep 26, 2014 at 11:29:56AM +0200, Thomas Gleixner wrote:
>> On Thu, 25 Sep 2014, Kevin Hilman wrote:
>> > Maybe I'm missing something, or maybe we're just lucky and nobody uses
>> > them together, but irq_set_affinity_notifier() only allows a single
>> > notifier to be registered at any given time. So if you had a system
>>
>> A single notifier per irq .....
>
> So what about two drivers wanting to use this notifier, but sharing an
> interrupt?
>
> It sounds to me like this notifier was misdesigned from the very start,
> and it should always have supported multiple notifiers.
I agree.
$SUBJECT patch tries to add that support, and is part of a series
wanting to use these notifiers in the PM QoS subsystem, while at the
same time not breaking existing users.
I suppose this series could be written without $SUBJECT patch, and
crossing fingers in the hopes that an existing user of the notifiers
doesn't also need to use the pm_qos constraints, but that seems like
knowingly leaving an armed landmine laying around.
Kevin
WARNING: multiple messages have this Message-ID (diff)
From: khilman@kernel.org (Kevin Hilman)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 3/4] irq: Allow multiple clients to register for irq affinity notification
Date: Fri, 26 Sep 2014 08:10:04 -0700 [thread overview]
Message-ID: <7hioka4dv7.fsf@deeprootsystems.com> (raw)
In-Reply-To: <20140926094003.GL5182@n2100.arm.linux.org.uk> (Russell King's message of "Fri, 26 Sep 2014 10:40:03 +0100")
Russell King - ARM Linux <linux@arm.linux.org.uk> writes:
> On Fri, Sep 26, 2014 at 11:29:56AM +0200, Thomas Gleixner wrote:
>> On Thu, 25 Sep 2014, Kevin Hilman wrote:
>> > Maybe I'm missing something, or maybe we're just lucky and nobody uses
>> > them together, but irq_set_affinity_notifier() only allows a single
>> > notifier to be registered at any given time. So if you had a system
>>
>> A single notifier per irq .....
>
> So what about two drivers wanting to use this notifier, but sharing an
> interrupt?
>
> It sounds to me like this notifier was misdesigned from the very start,
> and it should always have supported multiple notifiers.
I agree.
$SUBJECT patch tries to add that support, and is part of a series
wanting to use these notifiers in the PM QoS subsystem, while at the
same time not breaking existing users.
I suppose this series could be written without $SUBJECT patch, and
crossing fingers in the hopes that an existing user of the notifiers
doesn't also need to use the pm_qos constraints, but that seems like
knowingly leaving an armed landmine laying around.
Kevin
next prev parent reply other threads:[~2014-09-26 15:10 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-27 20:14 [PATCH v3 0/4] PM QoS: per-cpu PM QoS support Lina Iyer
2014-08-27 20:14 ` Lina Iyer
2014-08-27 20:14 ` [PATCH v3 1/4] QoS: Modify data structures and function arguments for scalability Lina Iyer
2014-08-27 20:14 ` Lina Iyer
2014-08-27 20:14 ` [PATCH v3 2/4] QoS: Enhance framework to support per-cpu PM QoS request Lina Iyer
2014-08-27 20:14 ` Lina Iyer
2014-08-27 20:14 ` [PATCH v3 3/4] irq: Allow multiple clients to register for irq affinity notification Lina Iyer
2014-08-27 20:14 ` Lina Iyer
2014-08-27 20:56 ` Thomas Gleixner
2014-08-27 20:56 ` Thomas Gleixner
2014-09-02 18:43 ` Lina Iyer
2014-09-02 18:43 ` Lina Iyer
2014-09-02 20:56 ` Thomas Gleixner
2014-09-02 20:56 ` Thomas Gleixner
[not found] ` <20140924221023.GD1004@ilina-mac.local>
2014-09-25 15:43 ` Lina Iyer
2014-09-25 15:43 ` Lina Iyer
2014-09-25 15:50 ` Lina Iyer
2014-09-25 15:50 ` Lina Iyer
2014-10-08 15:03 ` Thomas Gleixner
2014-10-08 15:03 ` Thomas Gleixner
2014-10-10 15:11 ` Lina Iyer
2014-10-10 15:11 ` Lina Iyer
2014-10-17 7:29 ` Thomas Gleixner
2014-10-17 7:29 ` Thomas Gleixner
2014-11-18 6:22 ` Lina Iyer
2014-11-18 6:22 ` Lina Iyer
2014-09-25 20:35 ` Kevin Hilman
2014-09-25 20:35 ` Kevin Hilman
2014-09-26 9:29 ` Thomas Gleixner
2014-09-26 9:29 ` Thomas Gleixner
2014-09-26 9:40 ` Russell King - ARM Linux
2014-09-26 9:40 ` Russell King - ARM Linux
2014-09-26 15:10 ` Kevin Hilman [this message]
2014-09-26 15:10 ` Kevin Hilman
2014-10-08 14:20 ` Thomas Gleixner
2014-10-08 14:20 ` Thomas Gleixner
2014-08-27 20:14 ` [PATCH v3 4/4] QoS: Enable PM QoS requests to apply only on smp_affinity of an IRQ Lina Iyer
2014-08-27 20:14 ` Lina Iyer
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