From: Marc Zyngier <maz@kernel.org>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
linux-tegra@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: IRQ thread timeouts and affinity
Date: Sat, 11 Oct 2025 11:00:11 +0100 [thread overview]
Message-ID: <87sefpoj10.wl-maz@kernel.org> (raw)
In-Reply-To: <graeplkpsgbolpnnq2pndpdb7fymyy7zvm37osbdtre347tns2@mjbgzwterefv>
On Fri, 10 Oct 2025 16:03:01 +0100,
Thierry Reding <thierry.reding@gmail.com> wrote:
>
> On Fri, Oct 10, 2025 at 03:18:13PM +0100, Marc Zyngier wrote:
> >
> > CPU hotplug is the main area of concern, and I'm pretty sure it breaks
> > this distribution mechanism (or the other way around). Another thing
> > is that if firmware isn't aware that 1:N interrupts can (or should)
> > wake-up a CPU from sleep, bad things will happen. Given that nobody
> > uses 1:N, you can bet that any bit of privileged SW (TF-A,
> > hypervisors) is likely to be buggy (I've already spotted bugs in KVM
> > around this).
>
> Okay, I can find out if CPU hotplug is a common use-case on these
> devices, or if we can run some tests with that.
It's not so much whether CPU hotplug is of any use to your particular
box, but whether this has any detrimental impact on *any* machine
doing CPU hotplug.
To be clear, this stuff doesn't go in if something breaks, no matter
how small.
M.
--
Without deviation from the norm, progress is not possible.
next prev parent reply other threads:[~2025-10-11 10:00 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-09 11:38 IRQ thread timeouts and affinity Thierry Reding
2025-10-09 14:30 ` Marc Zyngier
2025-10-09 16:05 ` Thierry Reding
2025-10-09 17:04 ` Marc Zyngier
2025-10-09 18:11 ` Marc Zyngier
2025-10-10 13:50 ` Thierry Reding
2025-10-10 14:18 ` Marc Zyngier
2025-10-10 14:38 ` Jon Hunter
2025-10-10 14:54 ` Thierry Reding
2025-10-10 15:52 ` Jon Hunter
2025-10-10 15:03 ` Thierry Reding
2025-10-11 10:00 ` Marc Zyngier [this message]
2025-10-14 10:50 ` Thierry Reding
2025-10-14 11:08 ` Thierry Reding
2025-10-14 17:46 ` Marc Zyngier
2025-10-16 18:53 ` Thomas Gleixner
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