Re: Control of IRQ Affinities from Userspace

[Frederic Weisbecker <frederic@kernel.org>]

Le Wed, Nov 26, 2025 at 10:20:53AM +0100, Florian Bezdeka a écrit :
> > drivers/net/ethernet/wangxun/libwx/wx_lib.c:1867:       nvecs = pci_alloc_irq_vectors_affinity(wx->pdev, nvecs,
> > drivers/nvme/host/pci.c:2659:   return pci_alloc_irq_vectors_affinity(pdev, 1, irq_queues, flags,
> > drivers/scsi/be2iscsi/be_main.c:3585:           if (pci_alloc_irq_vectors_affinity(phba->pcidev, 2, nvec,
> > drivers/scsi/csiostor/csio_isr.c:520:   cnt = pci_alloc_irq_vectors_affinity(hw->pdev, min, cnt,
> > drivers/scsi/hisi_sas/hisi_sas_v3_hw.c:2611:    vectors = pci_alloc_irq_vectors_affinity(pdev,
> > drivers/scsi/megaraid/megaraid_sas_base.c:5943: i = pci_alloc_irq_vectors_affinity(instance->pdev,
> > drivers/scsi/mpi3mr/mpi3mr_fw.c:862:            retval = pci_alloc_irq_vectors_affinity(mrioc->pdev,
> > drivers/scsi/mpt3sas/mpt3sas_base.c:3390:       i = pci_alloc_irq_vectors_affinity(ioc->pdev,
> > drivers/scsi/pm8001/pm8001_init.c:982:          rc = pci_alloc_irq_vectors_affinity(
> > drivers/scsi/qla2xxx/qla_isr.c:4539:            ret = pci_alloc_irq_vectors_affinity(ha->pdev, min_vecs,
> > drivers/virtio/virtio_pci_common.c:160: err = pci_alloc_irq_vectors_affinity(vp_dev->pci_dev, nvectors,
> > 
> > Not a so dead road :)
> 
> Grml... I definitely fat-fingered the query. Anyway, this housekeeping
> API still seems very boot-time oriented to me. Can't see yet where this
> housekeeping cpumasks are filled up by the cgroup/cpuset infrastructure.

It's on the way:
https://lore.kernel.org/all/20251105210348.35256-1-frederic@kernel.org/

If all goes well, not for the upcoming merge window but the next one.

> cgroups/cpusets don't care about "isolation" in that sense yet. It's
> just about cpumasks for compute. Am I missing something?

It's a bit more than just scheduler domain isolation. It also handles
kthreads and workqueues. It's also going to handle unbound timers (on the way
to the upcoming merge window).

Thanks.

> 
> 
> Florian

-- 
Frederic Weisbecker
SUSE Labs