I've splitted the parameter into input and output variable for
group_cpu_evenly as requested by Hannes.
The commit message on the "lib/group_cpus: honor housekeeping config when
grouping CPUs" is hopefully not missleading anymore. I've took the
liberty to updated the managed_irq documentation with the aim to reduce
confusion. I got some feedback that the text is hard to understand.
Obviously I added the warning on possible IO stalls when doing cpu
hotplug.
Daniel
(trimmed the To/Cc list, it was a bit large.)
Initial cover letter:
The nvme-pci driver is ignoring the isolcpus configuration. There were
several attempts to fix this in the past [1][2]. This is another attempt
but this time trying to address the feedback and solve it in the core
code.
The first patch introduces a new option for isolcpus 'io_queue', but I'm
not really sure if this is needed and we could just use the managed_irq
option instead. I guess depends if there is an use case which depens on
queues on the isolated CPUs.
The second patch introduces a new block layer helper which returns the
number of possible queues. I suspect it would makes sense also to make
this helper a bit smarter and also consider the number of queues the
hardware supports.
And the last patch updates the group_cpus_evenly function so that it uses
only the housekeeping CPUs when they are defined
Note this series is not addressing the affinity setting of the admin
queue (queue 0). I'd like to address this after we agreed on how to solve
this. Currently, the admin queue affinity can be controlled by the
irq_afffinity command line option, so there is at least a workaround for
it.
Baseline:
available: 2 nodes (0-1)
node 0 cpus: 0 1 2 3
node 0 size: 1536 MB
node 0 free: 1227 MB
node 1 cpus: 4 5 6 7
node 1 size: 1729 MB
node 1 free: 1422 MB
node distances:
node 0 1
0: 10 20
1: 20 10
options nvme write_queues=4 poll_queues=4
55: 0 41 0 0 0 0 0 0 PCI-MSIX-0000:00:05.0 0-edge nvme0q0 affinity: 0-3
63: 0 0 0 0 0 0 0 0 PCI-MSIX-0000:00:05.0 1-edge nvme0q1 affinity: 4-5
64: 0 0 0 0 0 0 0 0 PCI-MSIX-0000:00:05.0 2-edge nvme0q2 affinity: 6-7
65: 0 0 0 0 0 0 0 0 PCI-MSIX-0000:00:05.0 3-edge nvme0q3 affinity: 0-1
66: 0 0 0 0 0 0 0 0 PCI-MSIX-0000:00:05.0 4-edge nvme0q4 affinity: 2-3
67: 0 0 0 0 24 0 0 0 PCI-MSIX-0000:00:05.0 5-edge nvme0q5 affinity: 4
68: 0 0 0 0 0 1 0 0 PCI-MSIX-0000:00:05.0 6-edge nvme0q6 affinity: 5
69: 0 0 0 0 0 0 41 0 PCI-MSIX-0000:00:05.0 7-edge nvme0q7 affinity: 6
70: 0 0 0 0 0 0 0 3 PCI-MSIX-0000:00:05.0 8-edge nvme0q8 affinity: 7
71: 1 0 0 0 0 0 0 0 PCI-MSIX-0000:00:05.0 9-edge nvme0q9 affinity: 0
72: 0 18 0 0 0 0 0 0 PCI-MSIX-0000:00:05.0 10-edge nvme0q10 affinity: 1
73: 0 0 0 0 0 0 0 0 PCI-MSIX-0000:00:05.0 11-edge nvme0q11 affinity: 2
74: 0 0 0 3 0 0 0 0 PCI-MSIX-0000:00:05.0 12-edge nvme0q12 affinity: 3
queue mapping for /dev/nvme0n1
hctx0: default 4 5
hctx1: default 6 7
hctx2: default 0 1
hctx3: default 2 3
hctx4: read 4
hctx5: read 5
hctx6: read 6
hctx7: read 7
hctx8: read 0
hctx9: read 1
hctx10: read 2
hctx11: read 3
hctx12: poll 4 5
hctx13: poll 6 7
hctx14: poll 0 1
hctx15: poll 2 3
PCI name is 00:05.0: nvme0n1
irq 55, cpu list 0-3, effective list 1
irq 63, cpu list 4-5, effective list 5
irq 64, cpu list 6-7, effective list 7
irq 65, cpu list 0-1, effective list 1
irq 66, cpu list 2-3, effective list 3
irq 67, cpu list 4, effective list 4
irq 68, cpu list 5, effective list 5
irq 69, cpu list 6, effective list 6
irq 70, cpu list 7, effective list 7
irq 71, cpu list 0, effective list 0
irq 72, cpu list 1, effective list 1
irq 73, cpu list 2, effective list 2
irq 74, cpu list 3, effective list 3
* patched:
48: 0 0 33 0 0 0 0 0 PCI-MSIX-0000:00:05.0 0-edge nvme0q0 affinity: 0-3
58: 0 0 0 0 0 0 0 0 PCI-MSIX-0000:00:05.0 1-edge nvme0q1 affinity: 4
59: 0 0 0 0 0 0 0 0 PCI-MSIX-0000:00:05.0 2-edge nvme0q2 affinity: 5
60: 0 0 0 0 0 0 0 0 PCI-MSIX-0000:00:05.0 3-edge nvme0q3 affinity: 0
61: 0 0 0 0 0 0 0 0 PCI-MSIX-0000:00:05.0 4-edge nvme0q4 affinity: 1
62: 0 0 0 0 45 0 0 0 PCI-MSIX-0000:00:05.0 5-edge nvme0q5 affinity: 4
63: 0 0 0 0 0 12 0 0 PCI-MSIX-0000:00:05.0 6-edge nvme0q6 affinity: 5
64: 2 0 0 0 0 0 0 0 PCI-MSIX-0000:00:05.0 7-edge nvme0q7 affinity: 0
65: 0 35 0 0 0 0 0 0 PCI-MSIX-0000:00:05.0 8-edge nvme0q8 affinity: 1
queue mapping for /dev/nvme0n1
hctx0: default 2 3 4 6 7
hctx1: default 5
hctx2: default 0
hctx3: default 1
hctx4: read 4
hctx5: read 5
hctx6: read 0
hctx7: read 1
hctx8: poll 4
hctx9: poll 5
hctx10: poll 0
hctx11: poll 1
PCI name is 00:05.0: nvme0n1
irq 48, cpu list 0-3, effective list 2
irq 58, cpu list 4, effective list 4
irq 59, cpu list 5, effective list 5
irq 60, cpu list 0, effective list 0
irq 61, cpu list 1, effective list 1
irq 62, cpu list 4, effective list 4
irq 63, cpu list 5, effective list 5
irq 64, cpu list 0, effective list 0
irq 65, cpu list 1, effective list 1
[1] https://lore.kernel.org/lkml/20220423054331.GA17823@xxxxxx/T/#m9939195a465accbf83187caf346167c4242e798d
[2] https://lore.kernel.org/linux-nvme/87fruci5nj.ffs@tglx/
[3] https://lore.kernel.org/linux-nvme/20241202-refactor-blk-affinity-helpers-v6-0-27211e9c2cd5@xxxxxxxxxx/
Signed-off-by: Daniel Wagner <wagi@xxxxxxxxxx>
---
Changes in v5:
- rebased on latest for-6.14/block
- udpated documetation on managed_irq
- updated commit message "blk-mq: issue warning when offlining hctx with online isolcpus"
- split input/output parameter in "lib/group_cpus: let group_cpu_evenly return number of groups"
- dropped "sched/isolation: document HK_TYPE housekeeping option"
- Link to v4: https://lore.kernel.org/r/20241217-isolcpus-io-queues-v4-0-5d355fbb1e14@xxxxxxxxxx
Changes in v4:
- added "blk-mq: issue warning when offlining hctx with online isolcpus"
- fixed check in cgroup_cpus_evenly, the if condition needs to use
housekeeping_enabled() and not cpusmask_weight(housekeeping_masks),
because the later will always return a valid mask.
- dropped fixed tag from "lib/group_cpus.c: honor housekeeping config when
grouping CPUs"
- fixed overlong line "scsi: use block layer helpers to calculate num
of queues"
- dropped "sched/isolation: Add io_queue housekeeping option",
just document the housekeep enum hk_type
- added "lib/group_cpus: let group_cpu_evenly return number of groups"
- collected tags
- splitted series into a preperation series:
https://lore.kernel.org/linux-nvme/20241202-refactor-blk-affinity-helpers-v6-0-27211e9c2cd5@xxxxxxxxxx/
- Link to v3: https://lore.kernel.org/r/20240806-isolcpus-io-queues-v3-0-da0eecfeaf8b@xxxxxxx
Changes in v3:
- lifted a couple of patches from
https://lore.kernel.org/all/20210709081005.421340-1-ming.lei@xxxxxxxxxx/
"virito: add APIs for retrieving vq affinity"
"blk-mq: introduce blk_mq_dev_map_queues"
- replaces all users of blk_mq_[pci|virtio]_map_queues with
blk_mq_dev_map_queues
- updated/extended number of queue calc helpers
- add isolcpus=io_queue CPU-hctx mapping function
- documented enum hk_type and isolcpus=io_queue
- added "scsi: pm8001: do not overwrite PCI queue mapping"
- Link to v2: https://lore.kernel.org/r/20240627-isolcpus-io-queues-v2-0-26a32e3c4f75@xxxxxxx
Changes in v2:
- updated documentation
- splitted blk/nvme-pci patch
- dropped HK_TYPE_IO_QUEUE, use HK_TYPE_MANAGED_IRQ
- Link to v1: https://lore.kernel.org/r/20240621-isolcpus-io-queues-v1-0-8b169bf41083@xxxxxxx
---
Daniel Wagner (9):
lib/group_cpus: let group_cpu_evenly return number initialized masks
blk-mq: add number of queue calc helper
nvme-pci: use block layer helpers to calculate num of queues
scsi: use block layer helpers to calculate num of queues
virtio: blk/scsi: use block layer helpers to calculate num of queues
lib/group_cpus: honor housekeeping config when grouping CPUs
blk-mq: use hk cpus only when isolcpus=managed_irq is enabled
blk-mq: issue warning when offlining hctx with online isolcpus
doc: update managed_irq documentation
Documentation/admin-guide/kernel-parameters.txt | 46 +++++-----
block/blk-mq-cpumap.c | 116 +++++++++++++++++++++++-
block/blk-mq.c | 43 ++++++++-
drivers/block/virtio_blk.c | 5 +-
drivers/nvme/host/pci.c | 5 +-
drivers/scsi/megaraid/megaraid_sas_base.c | 15 +--
drivers/scsi/qla2xxx/qla_isr.c | 10 +-
drivers/scsi/smartpqi/smartpqi_init.c | 5 +-
drivers/scsi/virtio_scsi.c | 1 +
drivers/virtio/virtio_vdpa.c | 9 +-
fs/fuse/virtio_fs.c | 6 +-
include/linux/blk-mq.h | 2 +
include/linux/group_cpus.h | 3 +-
kernel/irq/affinity.c | 9 +-
lib/group_cpus.c | 90 +++++++++++++++++-
15 files changed, 304 insertions(+), 61 deletions(-)
---
base-commit: 844b8cdc681612ff24df62cdefddeab5772fadf1
change-id: 20240620-isolcpus-io-queues-1a88eb47ff8b
Best regards,
--
Daniel Wagner <wagi@xxxxxxxxxx>
