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From: Thomas Gleixner <tglx@linutronix.de>
To: Johan Hovold <johan@kernel.org>
Cc: Johan Hovold <johan+linaro@kernel.org>,
	Marc Zyngier <maz@kernel.org>,
	x86@kernel.org, platform-driver-x86@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org,
	linux-kernel@vger.kernel.org, Hsin-Yi Wang <hsinyi@chromium.org>,
	Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Subject: Re: [PATCH v4 19/19] irqdomain: Switch to per-domain locking
Date: Wed, 18 Jan 2023 14:09:22 +0100	[thread overview]
Message-ID: <87o7qwhtvh.ffs@tglx> (raw)
In-Reply-To: <Y8fBL+h2l5Wsiq2Z@hovoldconsulting.com>

On Wed, Jan 18 2023 at 10:51, Johan Hovold wrote:
> On Tue, Jan 17, 2023 at 10:50:39PM +0100, Thomas Gleixner wrote:
>> On Mon, Jan 16 2023 at 14:50, Johan Hovold wrote:
>> > The IRQ domain structures are currently protected by the global
>> > irq_domain_mutex. Switch to using more fine-grained per-domain locking,
>> > which may potentially speed up parallel probing somewhat.
>> 
>> Does it or not?
>> 
>> If not then why adding all this churn for no real value?
>
> It probably doesn't make much difference, but Marc wanted per-domain
> locking:
>
>     > I'd really like to avoid a global mutex. At the very least this should
>     > be a per-domain mutex, otherwise this will serialise a lot more than
>     > what is needed.

Sure it serializes more than what is needed, but the real question is
whether it matters. If it does not matter then I prefer KISS over a just
because we can optimization.

Thanks,

        tglx

WARNING: multiple messages have this Message-ID (diff)
From: Thomas Gleixner <tglx@linutronix.de>
To: Johan Hovold <johan@kernel.org>
Cc: Johan Hovold <johan+linaro@kernel.org>,
	Marc Zyngier <maz@kernel.org>,
	x86@kernel.org, platform-driver-x86@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org,
	linux-kernel@vger.kernel.org, Hsin-Yi Wang <hsinyi@chromium.org>,
	Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Subject: Re: [PATCH v4 19/19] irqdomain: Switch to per-domain locking
Date: Wed, 18 Jan 2023 14:09:22 +0100	[thread overview]
Message-ID: <87o7qwhtvh.ffs@tglx> (raw)
In-Reply-To: <Y8fBL+h2l5Wsiq2Z@hovoldconsulting.com>

On Wed, Jan 18 2023 at 10:51, Johan Hovold wrote:
> On Tue, Jan 17, 2023 at 10:50:39PM +0100, Thomas Gleixner wrote:
>> On Mon, Jan 16 2023 at 14:50, Johan Hovold wrote:
>> > The IRQ domain structures are currently protected by the global
>> > irq_domain_mutex. Switch to using more fine-grained per-domain locking,
>> > which may potentially speed up parallel probing somewhat.
>> 
>> Does it or not?
>> 
>> If not then why adding all this churn for no real value?
>
> It probably doesn't make much difference, but Marc wanted per-domain
> locking:
>
>     > I'd really like to avoid a global mutex. At the very least this should
>     > be a per-domain mutex, otherwise this will serialise a lot more than
>     > what is needed.

Sure it serializes more than what is needed, but the real question is
whether it matters. If it does not matter then I prefer KISS over a just
because we can optimization.

Thanks,

        tglx

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  reply	other threads:[~2023-01-18 13:40 UTC|newest]

Thread overview: 88+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-16 13:50 [PATCH v4 00/19] irqdomain: fix mapping race and clean up locking Johan Hovold
2023-01-16 13:50 ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 01/19] irqdomain: Drop bogus fwspec-mapping error handling Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-17 21:17   ` Thomas Gleixner
2023-01-17 21:17     ` Thomas Gleixner
2023-01-16 13:50 ` [PATCH v4 02/19] irqdomain: Drop dead domain-name assignment Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-17 21:18   ` Thomas Gleixner
2023-01-17 21:18     ` Thomas Gleixner
2023-01-16 13:50 ` [PATCH v4 03/19] irqdomain: Drop leftover brackets Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-17 21:19   ` Thomas Gleixner
2023-01-17 21:19     ` Thomas Gleixner
2023-01-18  9:05     ` Johan Hovold
2023-01-18  9:05       ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 04/19] irqdomain: Fix association race Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-17 21:20   ` Thomas Gleixner
2023-01-17 21:20     ` Thomas Gleixner
2023-01-16 13:50 ` [PATCH v4 05/19] irqdomain: Fix disassociation race Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 06/19] irqdomain: Drop revmap mutex Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-17 21:23   ` Thomas Gleixner
2023-01-17 21:23     ` Thomas Gleixner
2023-01-18  9:22     ` Johan Hovold
2023-01-18  9:22       ` Johan Hovold
2023-01-18 13:05       ` Thomas Gleixner
2023-01-18 13:05         ` Thomas Gleixner
2023-01-18 13:10         ` Johan Hovold
2023-01-18 13:10           ` Johan Hovold
2023-02-06 13:09           ` Thomas Gleixner
2023-02-06 13:09             ` Thomas Gleixner
2023-02-06 17:10             ` Johan Hovold
2023-02-06 17:10               ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 07/19] irqdomain: Look for existing mapping only once Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-17 21:34   ` Thomas Gleixner
2023-01-17 21:34     ` Thomas Gleixner
2023-01-18  9:26     ` Johan Hovold
2023-01-18  9:26       ` Johan Hovold
2023-02-09 13:00       ` Johan Hovold
2023-02-09 13:00         ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 08/19] irqdomain: Refactor __irq_domain_alloc_irqs() Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-17 21:34   ` Thomas Gleixner
2023-01-17 21:34     ` Thomas Gleixner
2023-01-18  9:30     ` Johan Hovold
2023-01-18  9:30       ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 09/19] irqdomain: Fix mapping-creation race Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-17 21:39   ` Thomas Gleixner
2023-01-17 21:39     ` Thomas Gleixner
2023-01-18  9:40     ` Johan Hovold
2023-01-18  9:40       ` Johan Hovold
2023-02-09 13:08       ` Johan Hovold
2023-02-09 13:08         ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 10/19] irqdomain: Clean up irq_domain_push/pop_irq() Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 11/19] x86/ioapic: Use irq_domain_create_hierarchy() Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-17 21:41   ` Thomas Gleixner
2023-01-17 21:41     ` Thomas Gleixner
2023-01-18 10:31     ` Johan Hovold
2023-01-18 10:31       ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 12/19] x86/apic: " Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 13/19] irqchip/alpine-msi: Use irq_domain_add_hierarchy() Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 14/19] irqchip/gic-v2m: Use irq_domain_create_hierarchy() Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 15/19] irqchip/gic-v3-its: " Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 16/19] irqchip/gic-v3-mbi: " Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 17/19] irqchip/loongson-pch-msi: " Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 18/19] irqchip/mvebu-odmi: " Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-16 13:50 ` [PATCH v4 19/19] irqdomain: Switch to per-domain locking Johan Hovold
2023-01-16 13:50   ` Johan Hovold
2023-01-17 21:50   ` Thomas Gleixner
2023-01-17 21:50     ` Thomas Gleixner
2023-01-18  9:51     ` Johan Hovold
2023-01-18  9:51       ` Johan Hovold
2023-01-18 13:09       ` Thomas Gleixner [this message]
2023-01-18 13:09         ` Thomas Gleixner

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