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Date: Thu, 30 Jul 2026 07:28:38 -0600
From: Keith Busch <kbusch@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: santhosh kumar <santhu.linux@gmail.com>, linux-kernel@vger.kernel.org,
	Christoph Hellwig <hch@lst.de>, Ming Lei <ming.lei@redhat.com>,
	x86@kernel.org
Subject: Re: [RFC] PCI_IRQ_AFFINITY limits MSI-X allocation on 384 CPU /
 1000+ NVMe system
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On Thu, Jul 30, 2026 at 03:16:46PM +0200, Thomas Gleixner wrote:
> As I told you before it's simple math and resource exhaustion due to the
> way how NVME is implemented and the x86 vector space limitations.
> 
> If you want that to behave differently, then you have to talk to the
> NVME people as I told you before.

We can introduce a module parameter to throttle down the maximum number
of IO queues to allocate per controller. I don't think the driver can
automatically reason out what the correct number should be because it
doesn't know how many devices it's going to see.