On Thu, Apr 16, 2026 at 03:29:29PM -0400, Aaron Tomlin wrote: > Please let me know your thoughts.
My apologies, I neglected to include the changelog. Changes in v11: - Completely rewrote the isolcpus=io_queue documentation in Documentation/admin-guide/kernel-parameters.txt to clarify its exclusive application to managed IRQs, queue allocation limits, vector exhaustion prevention, and hardware interrupt routing (Ming Lei) - Fixed a stack frame bloat issue by avoiding the on-stack declaration of struct cpumask (Waiman Long) - Linked to v10: https://lore.kernel.org/linux-nvme/[email protected]/ Changes in v10: - Fixed a page fault regression encountered when initialising secondary queue maps (e.g., NVMe poll queues). Restored the qmap->queue_offset to the mq_map assignment to ensure CPUs are strictly mapped to absolute hardware indices (Keith Busch) - Corrected the active_hctx tracker to utilise relative queue indices, preventing out-of-bounds mask assignments - Fixed the blk_mq_validate() sanity check to properly evaluate absolute queue indices against the offset-adjusted loop index - Corrected typographical errors within block/blk-mq-cpumap.c (Keith Busch) - Clarified the commit message regarding the removal of the !SMP fallback code, explicitly noting that the core scheduler now mandates SMP unconditionally (Sebastian Andrzej Siewior) - Added missing "Signed-off-by:" tags to properly record the patch series chain of custody - Linked to v9: https://lore.kernel.org/lkml/[email protected]/ Changes in v9: - Added "Reviewed-by:" tags - Introduced irq_spread_hk_filter() to safely restrict managed IRQ affinity to housekeeping CPUs (Thomas Gleixner) - Removed the unsafe global static variable blk_hk_online_mask from blk-mq-cpumap.c and blk-mq.c. blk_mq_online_queue_affinity() now returns a stable pointer, delegating safe intersection to the callers to prevent concurrent modification races (Thomas Gleixner, Hannes Reinecke) - Resolved BUG: kernel NULL pointer dereference in __blk_mq_all_tag_iter reported by the kernel test robot during cpuhotplug rcutorture stress testing - Linked to v8: https://lore.kernel.org/lkml/[email protected]/ Changes in v8: - Added commit 524f5eea4bbe ("lib/group_cpus: remove !SMP code") - Merged the new mapping logic directly into the existing function to avoid special casing - Refined the group_mask_cpus_evenly() implementation with the following updates: - Corrected the function name typo (changed group_masks_cpus_evenly to group_mask_cpus_evenly) - Updated the documentation comment to accurately reflect the function's behavior - Renamed the cpu_mask argument to mask for consistency - Added a new patch for aacraid to include the missing number of queues calculation - Restricted updates to only affect SCSI drivers that support PCI_IRQ_AFFINITY and do not utilize nvme-fabrics - Removed the __free cleanup attribute usage for cpumask_var_t allocations due to compatibility issues - Updated the documentation to explicitly highlight the limitations surrounding CPU offlining - Collected accumulated Reviewed-by and Acked-by tags - Linked to v7: https://patch.msgid.link/[email protected] Changes in v7: - Sent out the first part of the series independently: https://lore.kernel.org/all/[email protected]/ - Added comprehensive kernel command-line documentation - Added validation logic to ensure the resulting CPU-to-queue mapping is fully operational - Rewrote the isolcpus mapping code to properly account for active hardware contexts (hctx) - Introduced blk_mq_map_hk_irq_queues, which utilizes the mask retrieved from irq_get_affinity() - Refactored blk_mq_map_hk_queues to require the caller to explicitly test for HK_TYPE_MANAGED_IRQ - Linked to v6: https://patch.msgid.link/[email protected] Changes in v6: - Reintroduced the io_queue type for the isolcpus kernel parameter - Prevented the offlining of a housekeeping CPU if an isolated CPU is still present, upgrading this behavior from a simple warning to a hard restriction - Linked to v5: https://lore.kernel.org/r/[email protected] Changes in v5: - Rebased the series onto the latest for-6.14/block branch. - Updated the documentation regarding the managed_irq parameters - Reworded the commit message for "blk-mq: issue warning when offlining hctx with online isolcpus" for better clarity - Split the input and output parameters in the patch "lib/group_cpus: let group_cpu_evenly return number of groups" - Dropped the patch "sched/isolation: document HK_TYPE housekeeping option" - Linked to v4: https://lore.kernel.org/r/[email protected] Changes in v4: - Added the patch "blk-mq: issue warning when offlining hctx with online isolcpus" - Fixed the check in group_cpus_evenly(); the condition now properly uses housekeeping_enabled() instead of cpumask_weight(), as the latter always returns a valid mask - Dropped the Fixes: tag from "lib/group_cpus.c: honor housekeeping config when grouping CPUs" - Fixed an overlong line warning in the patch "scsi: use block layer helpers to calculate num of queues" - Dropped the patch "sched/isolation: Add io_queue housekeeping option" in favor of simply documenting the housekeeping hk_type enum - Added the patch "lib/group_cpus: let group_cpu_evenly return number of groups" - Collected accumulated Reviewed-by and Acked-by tags - Split the patchset by moving foundational changes into a separate preparation series: https://lore.kernel.org/linux-nvme/20241202-refactor-blk-affinity-helpers-v6-0-27211e9c2...@kernel.org/ - Linked to v3: https://lore.kernel.org/r/[email protected] Changes in v3: - Integrated patches from Ming Lei (https://lore.kernel.org/all/[email protected]/): "virtio: add APIs for retrieving vq affinity" and "blk-mq: introduce blk_mq_dev_map_queues" - Replaced all instances of blk_mq_pci_map_queues and blk_mq_virtio_map_queues with the new unified blk_mq_dev_map_queues - Updated and expanded the helper functions used for calculating the number of queues - Added the CPU-to-hctx mapping function specifically to support the isolcpus=io_queue parameter - Documented the hk_type enum and the newly introduced isolcpus=io_queue parameter - Added the patch "scsi: pm8001: do not overwrite PCI queue mapping" - Linked to v2: https://lore.kernel.org/r/[email protected] Changes in v2: - Updated the feature documentation for clarity and completeness - Split the blk/nvme-pci patch into smaller, logical commits - Dropped the HK_TYPE_IO_QUEUE macro in favor of reusing HK_TYPE_MANAGED_IRQ - Linked to v1: https://lore.kernel.org/r/[email protected] > > Aaron Tomlin (1): > genirq/affinity: Restrict managed IRQ affinity to housekeeping CPUs > > Daniel Wagner (12): > scsi: aacraid: use block layer helpers to calculate num of queues > lib/group_cpus: remove dead !SMP code > lib/group_cpus: Add group_mask_cpus_evenly() > genirq/affinity: Add cpumask to struct irq_affinity > blk-mq: add blk_mq_{online|possible}_queue_affinity > nvme-pci: use block layer helpers to constrain queue affinity > scsi: Use block layer helpers to constrain queue affinity > virtio: blk/scsi: use block layer helpers to constrain queue affinity > isolation: Introduce io_queue isolcpus type > blk-mq: use hk cpus only when isolcpus=io_queue is enabled > blk-mq: prevent offlining hk CPUs with associated online isolated CPUs > docs: add io_queue flag to isolcpus > > .../admin-guide/kernel-parameters.txt | 30 ++- > block/blk-mq-cpumap.c | 192 ++++++++++++++++-- > block/blk-mq.c | 42 ++++ > drivers/block/virtio_blk.c | 4 +- > drivers/nvme/host/pci.c | 1 + > drivers/scsi/aacraid/comminit.c | 3 +- > 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/virtio_scsi.c | 5 +- > include/linux/blk-mq.h | 2 + > include/linux/group_cpus.h | 3 + > include/linux/interrupt.h | 16 +- > include/linux/sched/isolation.h | 1 + > kernel/irq/affinity.c | 38 +++- > kernel/sched/isolation.c | 7 + > lib/group_cpus.c | 65 ++++-- > 19 files changed, 379 insertions(+), 48 deletions(-) > > > base-commit: 3cd8b194bf3428dfa53120fee47e827a7c495815 > -- > 2.51.0 > -- Aaron Tomlin
