Re: [RFC] PCI_IRQ_AFFINITY limits MSI-X allocation on 384 CPU / 1000+ NVMe system

[Christoph Hellwig]

On Mon, Aug 03, 2026 at 05:43:59AM -1000, Keith Busch wrote:
> On Thu, Jul 30, 2026 at 09:44:21PM +0200, Thomas Gleixner wrote:
> > On Thu, Jul 30 2026 at 07:28, Keith Busch wrote:
> > > 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.
> > 
> > I might be missing something here as usual, but the number of io queues
> > per controller does not affect that at all as I explained before.
> 
> Oh, you did explain that. I skipped to the end as I had too many
> distractions last week. Sorry about that, and thanks for the
> re-explanation.
> 
> I mistakenly was thinking the effective_affinity was the only hardware
> resource used. Back to the drawing board.

But given that we don't use multiple tag_set by default this can't
be the issue of the reported unless they didnt report enabling
multiple tag sets.