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

[Kleber Souza]

On 05/15/18 06:03, Jose Ricardo Ziviani wrote:
> 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(-)
> 

The changes don't seem as intrusive as I first thought, they don't
introduce so many new features and are in majority follow-up fixes. As
Stefan mentioned, the patch set seems to be carrying all the fixes sent
upstream so far.

Acked-by: Kleber Sacilotto de Souza <kleber.souza at canonical.com>