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* [PATCH V7 0/3] blk-mq: fix blk_mq_alloc_request_hctx
@ 2021-08-18 14:44 Ming Lei
  2021-08-18 14:44 ` [PATCH V7 1/3] genirq: add device_has_managed_msi_irq Ming Lei
                   ` (3 more replies)
  0 siblings, 4 replies; 13+ messages in thread
From: Ming Lei @ 2021-08-18 14:44 UTC (permalink / raw)
  To: Jens Axboe, Christoph Hellwig, linux-block, Thomas Gleixner
  Cc: John Garry, Sagi Grimberg, Daniel Wagner, Wen Xiong, Ming Lei

Hi,

blk_mq_alloc_request_hctx() is used by NVMe fc/rdma/tcp/loop to connect
io queue. Also the sw ctx is chosen as the 1st online cpu in hctx->cpumask.
However, all cpus in hctx->cpumask may be offline.

This usage model isn't well supported by blk-mq which supposes allocator is
always done on one online CPU in hctx->cpumask. This assumption is
related with managed irq, which also requires blk-mq to drain inflight
request in this hctx when the last cpu in hctx->cpumask is going to
offline.

However, NVMe fc/rdma/tcp/loop don't use managed irq, so we should allow
them to ask for request allocation when the specified hctx is inactive
(all cpus in hctx->cpumask are offline). Fix blk_mq_alloc_request_hctx() by
allowing to allocate request when all CPUs of this hctx are offline.

Wen Xiong has verified V4 in her nvmef test.

V7:
	- move blk_mq_hctx_use_managed_irq() into block/blk-mq.c, 3/3

V6:
	- move device_has_managed_msi_irq() into kernel/irq/msi.c

V5:
	- take John Garry's suggestion to replace device field with
	new helper of device_has_managed_msi_irq()
V4:
	- remove patches for cleanup queue map helpers
	- take Christoph's suggestion to add field into 'struct device' for
	describing if managed irq is allocated from one device

V3:
	- cleanup map queues helpers, and remove pci/virtio/rdma queue
	  helpers
	- store use managed irq info into qmap

V2:
	- use flag of BLK_MQ_F_MANAGED_IRQ
	- pass BLK_MQ_F_MANAGED_IRQ from driver explicitly
	- kill BLK_MQ_F_STACKING


Ming Lei (3):
  genirq: add device_has_managed_msi_irq
  blk-mq: mark if one queue map uses managed irq
  blk-mq: don't deactivate hctx if managed irq isn't used

 block/blk-mq-pci.c                     |  2 ++
 block/blk-mq-rdma.c                    |  7 ++++++
 block/blk-mq-virtio.c                  |  2 ++
 block/blk-mq.c                         | 35 ++++++++++++++++++--------
 drivers/scsi/hisi_sas/hisi_sas_v2_hw.c |  1 +
 include/linux/blk-mq.h                 |  3 ++-
 include/linux/msi.h                    |  5 ++++
 kernel/irq/msi.c                       | 18 +++++++++++++
 8 files changed, 62 insertions(+), 11 deletions(-)

-- 
2.31.1


^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2021-10-11 18:23 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-18 14:44 [PATCH V7 0/3] blk-mq: fix blk_mq_alloc_request_hctx Ming Lei
2021-08-18 14:44 ` [PATCH V7 1/3] genirq: add device_has_managed_msi_irq Ming Lei
2021-10-11 18:23   ` Varad Gautam
2021-08-18 14:44 ` [PATCH V7 2/3] blk-mq: mark if one queue map uses managed irq Ming Lei
2021-08-23 17:17   ` Sagi Grimberg
2021-08-18 14:44 ` [PATCH V7 3/3] blk-mq: don't deactivate hctx if managed irq isn't used Ming Lei
2021-08-23 17:18   ` Sagi Grimberg
2021-09-15 16:14   ` Daniel Wagner
2021-09-16  2:17     ` Ming Lei
2021-09-16  7:42       ` Daniel Wagner
2021-09-16  8:13         ` Ming Lei
2021-10-04 12:25           ` [RFC] nvme-fc: Allow managed IRQs Daniel Wagner
2021-08-19 22:38 ` [PATCH V7 0/3] blk-mq: fix blk_mq_alloc_request_hctx Ming Lei

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