[PATCH V4 0/6] genirq/affinity: Abstract APIs from managed irq affinity spread

Ming Lei
2022-12-27T02:30:18Z

Hello,

irq_build_affinity_masks() actually grouping CPUs evenly into each managed
irq vector according to NUMA and CPU locality, and it is reasonable to abstract
one generic API for grouping CPUs evenly, the idea is suggested by Thomas
Gleixner.

group_cpus_evenly() is abstracted and put into lib/, so blk-mq can re-use
it to build default queue mapping.

blk-mq IO perf data is observed as more stable, meantime with big
improvement, see detailed data in the last patch.

Please consider it for v6.3!

V4:
- address comments from John, not export the API, given so far no
module uses this symbol
- add maintainer entry for new added lib/group_cpus.c
- rebase on 6.2

V3:
- fix build failure in case of !CONFIG_SMP, only 6/7 is changed

V2:
- fix build failure in case of !CONFIG_SMP
- fix commit log typo
- fix memory leak in last patch
- add reviewed-by

Since RFC:
- remove RFC
- rebase on -next tree

Ming Lei (6):
genirq/affinity: Remove the 'firstvec' parameter from
irq_build_affinity_masks
genirq/affinity: Pass affinity managed mask array to
irq_build_affinity_masks
genirq/affinity: Don't pass irq_affinity_desc array to
irq_build_affinity_masks
genirq/affinity: Rename irq_build_affinity_masks as group_cpus_evenly
genirq/affinity: Move group_cpus_evenly() into lib/
blk-mq: Build default queue map via group_cpus_evenly()

MAINTAINERS | 2 +
block/blk-mq-cpumap.c | 63 ++----
include/linux/group_cpus.h | 14 ++
kernel/irq/affinity.c | 405 +----------------------------------
lib/Makefile | 2 +
lib/group_cpus.c | 427 +++++++++++++++++++++++++++++++++++++
6 files changed, 467 insertions(+), 446 deletions(-)
create mode 100644 include/linux/group_cpus.h
create mode 100644 lib/group_cpus.c

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2.31.1