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Subject[PATCH V2 0/4] genirq/affinity: add .calc_sets for improving IRQ allocation & spread
Date
Hi,

Currently pre-caculated set vectors are provided by driver for
allocating & spread vectors. This way only works when drivers passes
same 'max_vecs' and 'min_vecs' to pci_alloc_irq_vectors_affinity(),
also requires driver to retry the allocating & spread.

As Bjorn and Keith mentioned, the current usage & interface for irq sets
is a bit awkward because the retrying should have been avoided by providing
one resonable 'min_vecs'. However, if 'min_vecs' isn't same with
'max_vecs', number of the allocated vectors is unknown before calling
pci_alloc_irq_vectors_affinity(), then each set's vectors can't be
pre-caculated.

Add a new callback of .calc_sets into 'struct irq_affinity' so that
driver can caculate set vectors after IRQ vector is allocated and
before spread IRQ vectors. Add 'priv' so that driver may retrieve
its private data via the 'struct irq_affinity'.


V2:
- add .calc_sets instead of .setup_affinity() which is easy to
be abused by drivers

Ming Lei (4):
genirq/affinity: store irq set vectors in 'struct irq_affinity'
genirq/affinity: add new callback for caculating set vectors
nvme-pci: avoid irq allocation retrying via .calc_sets
genirq/affinity: Document .calc_sets as required in case of multiple
sets

drivers/nvme/host/pci.c | 63 ++++++++++++-----------------------------------
drivers/pci/msi.c | 4 +--
include/linux/interrupt.h | 13 +++++++---
kernel/irq/affinity.c | 19 +++++++++-----
4 files changed, 41 insertions(+), 58 deletions(-)

--
2.9.5

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