Re: [PATCH v6 3/9] nvme-pci: use block layer helpers to calculate num of queues

Daniel Wagner
2025-05-14T16:12:10Z

On Fri, May 09, 2025 at 09:47:31AM +0800, Ming Lei wrote:
> On Thu, Apr 24, 2025 at 08:19:42PM +0200, Daniel Wagner wrote:
> > Multiqueue devices should only allocate queues for the housekeeping CPUs
> > when isolcpus=io_queue is set. This avoids that the isolated CPUs get
> > disturbed with OS workload.
>
> The commit log needs to be updated:
>
> - io_queue isn't introduced yet
>
> - this patch can only reduce nr_hw_queues, and queue mapping isn't changed
> yet, so nothing to do with
>
> "This avoids that the isolated CPUs get disturbed with OS workload"

What about:

The calculation of the upper limit for queues does not depend solely on
the number of possible CPUs; for example, the isolcpus kernel
command-line option must also be considered.

To account for this, the block layer provides a helper function to
retrieve the maximum number of queues. Use it to set an appropriate
upper queue number limit.

I would use this version for the other patches as well,
s/possible/online/ where necessary.