From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Jakub Kicinski <kuba@kernel.org>,
Florian Bezdeka <florian.bezdeka@siemens.com>,
Maxime Chevallier <maxime.chevallier@bootlin.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre Torgue <alexandre.torgue@foss.st.com>,
Yury Norov <yury.norov@gmail.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Andrew Morton <akpm@linux-foundation.org>,
Clark Williams <clrkwllms@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@kernel.org>,
netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev
Subject: Re: [PATCH RFC 2/3] genirq: Honor existing IRQ affinities when setting affinity hints
Date: Fri, 21 Aug 2026 12:53:10 +0200 [thread overview]
Message-ID: <20260821105310.ZRK2TO93@linutronix.de> (raw)
In-Reply-To: <11c2d3c4-ea05-46a2-8579-c5aba1bfa204@siemens.com>
On 2026-08-21 12:38:52 [+0200], Jan Kiszka wrote:
> Fully agree: drivers should not set affinities. They should just express
> desires or additional constraints. The ultimately resulting affinity for
> an IRQ should be the result of the various constraints that kernel and
> userland may express via NUMA placements, isolcpus, some dynamic
> isolation/grouping constraints, or you-name-it.
You might want to look at irq_create_affinity_masks()/
group_cpus_evenly() which attempts to spread irqs evenly across CPUs/
NUMA nodes. This is used by storage is considered a bit by the
isolcpus=managed_irq option.
> I think we need a big picture how things should eventually look like and
> then develop a strategy how to step-wise convert existing code.
>
> Jan
Sebastian
next prev parent reply other threads:[~2026-08-21 10:53 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-19 14:30 [PATCH RFC 0/3] genirq: Allow drivers to respect userspace IRQ affinities Florian Bezdeka
2026-08-19 14:30 ` [PATCH RFC 1/3] cpumask: Honor irq_default_affinity in cpumask_local_spread() Florian Bezdeka
2026-08-19 18:38 ` Yury Norov
2026-08-20 16:09 ` Sebastian Andrzej Siewior
2026-08-19 14:30 ` [PATCH RFC 2/3] genirq: Honor existing IRQ affinities when setting affinity hints Florian Bezdeka
2026-08-20 16:41 ` Jakub Kicinski
2026-08-21 10:38 ` Jan Kiszka
2026-08-21 10:53 ` Sebastian Andrzej Siewior [this message]
2026-08-19 14:30 ` [PATCH RFC 3/3] net: stmmac: Migrate IRQ balancing to cpumask_local_spread() Florian Bezdeka
2026-08-19 18:45 ` Yury Norov
2026-08-19 18:28 ` [PATCH RFC 0/3] genirq: Allow drivers to respect userspace IRQ affinities Yury Norov
2026-08-19 23:54 ` Andrew Lunn
2026-08-20 0:10 ` Andrew Lunn
2026-08-20 15:12 ` Sebastian Andrzej Siewior
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