This series adds support for multiple queue maps for blk-mq. Since blk-mq was introduced, it's only support a single queue map. This means you can have 1 set of queues, and the mapping purely depends on what CPU an IO originated from. With this patch set, drivers can implement mappings that depend on both CPU and request type - and they can have multiple sets of mappings. NVMe is used as a proof of concept. It adds support for a separate write queue set. One way to use this would be to limit the number of write queues to favor reads, since NVMe does round-robin service of queues. An easy extension of this would be to add multiple sets of queues, for prioritized IO. NVMe also uses this feature to finally make the polling work efficiently, without triggering interrupts. This both increases performance (and decreases latency), at a lower system load. At the same time it's more flexible, as you don't have to worry about IRQ coalescing and redirection to avoid interrupts disturbing the workload. This is how polling should have worked from day 1. This is on top of the mq-conversions branch and series just posted. It can also be bound in my mq-maps branch. block/blk-flush.c | 7 +- block/blk-mq-cpumap.c | 19 +-- block/blk-mq-debugfs.c | 4 +- block/blk-mq-pci.c | 10 +- block/blk-mq-rdma.c | 4 +- block/blk-mq-sched.c | 18 ++- block/blk-mq-sysfs.c | 10 ++ block/blk-mq-tag.c | 5 +- block/blk-mq-virtio.c | 8 +- block/blk-mq.c | 213 ++++++++++++++++++++---------- block/blk-mq.h | 29 ++++- block/blk.h | 6 +- block/kyber-iosched.c | 6 +- drivers/block/virtio_blk.c | 2 +- drivers/nvme/host/pci.c | 238 ++++++++++++++++++++++++++++++---- drivers/scsi/qla2xxx/qla_os.c | 5 +- drivers/scsi/scsi_lib.c | 2 +- drivers/scsi/smartpqi/smartpqi_init.c | 3 +- drivers/scsi/virtio_scsi.c | 3 +- fs/block_dev.c | 2 + fs/direct-io.c | 2 + fs/iomap.c | 9 +- include/linux/blk-mq-pci.h | 4 +- include/linux/blk-mq-virtio.h | 4 +- include/linux/blk-mq.h | 24 +++- include/linux/blk_types.h | 4 +- include/linux/blkdev.h | 2 - include/linux/interrupt.h | 4 + kernel/irq/affinity.c | 31 ++++- 29 files changed, 520 insertions(+), 158 deletions(-) -- Jens Axboe
