Re: [PATCH v7 05/10] scsi: Use block layer helpers to constrain queue affinity

[Hannes Reinecke <hare@suse.de>]

On 7/2/25 18:33, Daniel Wagner wrote:
> Ensure that IRQ affinity setup also respects the queue-to-CPU mapping
> constraints provided by the block layer. This allows the SCSI drivers
> to avoid assigning interrupts to CPUs that the block layer has excluded
> (e.g., isolated CPUs).
> 
> Signed-off-by: Daniel Wagner <wagi@kernel.org>
> ---
>   drivers/scsi/fnic/fnic_isr.c              | 7 +++++--
>   drivers/scsi/hisi_sas/hisi_sas_v3_hw.c    | 1 +
>   drivers/scsi/megaraid/megaraid_sas_base.c | 5 ++++-
>   drivers/scsi/mpi3mr/mpi3mr_fw.c           | 6 +++++-
>   drivers/scsi/mpt3sas/mpt3sas_base.c       | 5 ++++-
>   drivers/scsi/pm8001/pm8001_init.c         | 1 +
>   drivers/scsi/qla2xxx/qla_isr.c            | 1 +
>   drivers/scsi/smartpqi/smartpqi_init.c     | 7 +++++--
>   8 files changed, 26 insertions(+), 7 deletions(-)
 >

All of these drivers are not aware of CPU hotplug, and as such
will not be notified when the number of CPUs changes.
But you use 'blk_mq_online_queue_affinity()' for all of these
drivers.
Wouldn't 'blk_mq_possible_queue_affinit()' a better choice here
to insulate against CPU hotplug effects?

Also some drivers which are using irq affinity (eg aacraid, lpfc) are
missing from these conversions. Why?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
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