From: Johan Hovold <johan@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
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
Subject: Re: [PATCH v3 19/19] irqdomain: Switch to per-domain locking
Date: Mon, 12 Dec 2022 15:29:35 +0100 [thread overview]
Message-ID: <Y5c6z3t+sV/kIMjF@hovoldconsulting.com> (raw)
In-Reply-To: <87mt7sbtf9.ffs@tglx>
On Mon, Dec 12, 2022 at 03:14:34PM +0100, Thomas Gleixner wrote:
> On Fri, Dec 09 2022 at 15:01, 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.
> >
> > Note that the domain lock of the root domain (innermost domain) must be
> > used for hierarchical domains. For non-hierarchical domain (as for root
> > domains), the new root pointer is set to the domain itself so that
> > domain->root->mutex can be used in shared code paths.
> >
> > Also note that hierarchical domains should be constructed using
> > irq_domain_create_hierarchy() (or irq_domain_add_hierarchy()) to avoid
> > poking at irqdomain internals.
>
> While I agree in principle, this change really makes me nervous.
>
> Any fail in setting up domain->root correctly, e.g. by not using
> irq_domain_create_hierarchy(), cannot be detected and creates nasty to
> debug race conditions.
>
> So we need some debug mechanism which allows to validate that
> domain->root is set up correctly when domain->parent != NULL.
Lockdep will catch that due to the
lockdep_assert_held(&domain->root->mutex);
I added to irq_domain_set_mapping() and which is is called for each
(inner) domain in a hierarchy when allocating an IRQ.
Johan
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next prev parent reply other threads:[~2022-12-12 14:30 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-09 14:01 [PATCH v3 00/19] irqdomain: fix mapping race and clean up locking Johan Hovold
2022-12-09 14:01 ` [PATCH v3 01/19] irqdomain: Drop bogus fwspec-mapping error handling Johan Hovold
2022-12-09 14:01 ` [PATCH v3 02/19] irqdomain: Drop dead domain-name assignment Johan Hovold
2022-12-09 14:01 ` [PATCH v3 03/19] irqdomain: Drop leftover brackets Johan Hovold
2022-12-12 22:44 ` Philippe Mathieu-Daudé
2022-12-09 14:01 ` [PATCH v3 04/19] irqdomain: Fix association race Johan Hovold
2022-12-09 14:01 ` [PATCH v3 05/19] irqdomain: Fix disassociation race Johan Hovold
2022-12-09 14:01 ` [PATCH v3 06/19] irqdomain: Drop revmap mutex Johan Hovold
2022-12-09 14:01 ` [PATCH v3 07/19] irqdomain: Look for existing mapping only once Johan Hovold
2022-12-09 14:01 ` [PATCH v3 08/19] irqdomain: Refactor __irq_domain_alloc_irqs() Johan Hovold
2022-12-09 14:01 ` [PATCH v3 09/19] irqdomain: Fix mapping-creation race Johan Hovold
2022-12-09 14:01 ` [PATCH v3 10/19] irqdomain: Clean up irq_domain_push/pop_irq() Johan Hovold
2022-12-12 22:32 ` Philippe Mathieu-Daudé
2022-12-09 14:01 ` [PATCH v3 11/19] x86/ioapic: Use irq_domain_create_hierarchy() Johan Hovold
2022-12-12 22:37 ` Philippe Mathieu-Daudé
2022-12-09 14:01 ` [PATCH v3 12/19] x86/apic: " Johan Hovold
2022-12-12 22:41 ` Philippe Mathieu-Daudé
2022-12-09 14:01 ` [PATCH v3 13/19] irqchip/alpine-msi: Use irq_domain_add_hierarchy() Johan Hovold
2022-12-12 22:41 ` Philippe Mathieu-Daudé
2022-12-09 14:01 ` [PATCH v3 14/19] irqchip/gic-v2m: Use irq_domain_create_hierarchy() Johan Hovold
2022-12-12 22:42 ` Philippe Mathieu-Daudé
2022-12-09 14:01 ` [PATCH v3 15/19] irqchip/gic-v3-its: " Johan Hovold
2022-12-09 14:01 ` [PATCH v3 16/19] irqchip/gic-v3-mbi: " Johan Hovold
2022-12-12 22:42 ` Philippe Mathieu-Daudé
2022-12-09 14:01 ` [PATCH v3 17/19] irqchip/loongson-pch-msi: " Johan Hovold
2022-12-12 22:36 ` Philippe Mathieu-Daudé
2022-12-09 14:01 ` [PATCH v3 18/19] irqchip/mvebu-odmi: " Johan Hovold
2022-12-12 22:37 ` Philippe Mathieu-Daudé
2022-12-09 14:01 ` [PATCH v3 19/19] irqdomain: Switch to per-domain locking Johan Hovold
2022-12-12 14:14 ` Thomas Gleixner
2022-12-12 14:29 ` Johan Hovold [this message]
2022-12-12 16:18 ` Thomas Gleixner
2023-01-11 18:28 ` Thomas Gleixner
2023-01-12 17:21 ` Johan Hovold
2022-12-09 15:51 ` [PATCH v3 00/19] irqdomain: fix mapping race and clean up locking Thomas Gleixner
2022-12-09 16:16 ` Johan Hovold
2022-12-09 19:53 ` Thomas Gleixner
2022-12-15 9:31 ` Hsin-Yi Wang
2023-01-16 13:53 ` Johan Hovold
2022-12-20 3:30 ` [PATCH v3 0/19] " Mark-PK Tsai
2023-01-16 13:55 ` Johan Hovold
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