[Bionic][PATCH v3 00/21] blk-mq scheduler fixes

[Jose Ricardo Ziviani]

From: Jose Ricardo Ziviani <joserz at linux.ibm.com>

Hello team!

Weeks ago I sent a patchset with:
 * genirq/affinity: Spread irq vectors among present CPUs as far as possible
 * blk-mq: simplify queue mapping & schedule with each possisble CPU

Unfortunately they broke some cases, in particular the hpsa driver, so they
had to be reverted. However, the bugs in blk_mq are leading to a very
unstable KVM/Qemu virtual machines whenever CPU hotplug/unplug and SMT
changes are performed, also impacting live migration.

So, this is a new attempt to have the patches included. This new version
includes all related fixes available upstream.

It's based on Ubuntu-4.15.0-21.22 tag.

V3:
 - Added Buglink line in each commit

V2:
 - Included all the fix necessary to blk_mq

Thank you!

Jose Ricardo Ziviani

Bart Van Assche (1):
  blk-mq: Avoid that blk_mq_delay_run_hw_queue() introduces unintended
    delays

Christoph Hellwig (2):
  genirq/affinity: assign vectors to all possible CPUs
  blk-mq: simplify queue mapping & schedule with each possisble CPU

Jens Axboe (1):
  blk-mq: fix discard merge with scheduler attached

Ming Lei (16):
  genirq/affinity: Rename *node_to_possible_cpumask as *node_to_cpumask
  genirq/affinity: Move actual irq vector spreading into a helper
    function
  genirq/affinity: Allow irq spreading from a given starting point
  genirq/affinity: Spread irq vectors among present CPUs as far as
    possible
  blk-mq: make sure hctx->next_cpu is set correctly
  blk-mq: make sure that correct hctx->next_cpu is set
  blk-mq: don't keep offline CPUs mapped to hctx 0
  blk-mq: avoid to write intermediate result to hctx->next_cpu
  blk-mq: introduce blk_mq_hw_queue_first_cpu() to figure out first cpu
  blk-mq: don't check queue mapped in __blk_mq_delay_run_hw_queue()
  nvme: pci: pass max vectors as num_possible_cpus() to
    pci_alloc_irq_vectors
  scsi: hpsa: fix selection of reply queue
  scsi: megaraid_sas: fix selection of reply queue
  scsi: core: introduce force_blk_mq
  scsi: virtio_scsi: fix IO hang caused by automatic irq vector affinity
  scsi: virtio_scsi: unify scsi_host_template

Thomas Gleixner (1):
  genirq/affinity: Don't return with empty affinity masks on error

 block/blk-core.c                            |   2 +
 block/blk-merge.c                           |  29 +++-
 block/blk-mq-cpumap.c                       |   5 -
 block/blk-mq.c                              |  65 +++++---
 drivers/nvme/host/pci.c                     |   2 +-
 drivers/scsi/hosts.c                        |   1 +
 drivers/scsi/hpsa.c                         |  73 ++++++---
 drivers/scsi/hpsa.h                         |   1 +
 drivers/scsi/megaraid/megaraid_sas.h        |   1 +
 drivers/scsi/megaraid/megaraid_sas_base.c   |  39 ++++-
 drivers/scsi/megaraid/megaraid_sas_fusion.c |  12 +-
 drivers/scsi/virtio_scsi.c                  | 129 ++-------------
 include/scsi/scsi_host.h                    |   3 +
 kernel/irq/affinity.c                       | 166 +++++++++++++-------
 14 files changed, 296 insertions(+), 232 deletions(-)

-- 
2.17.0