From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
linux-block@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
John Garry <john.garry@huawei.com>,
Sagi Grimberg <sagi@grimberg.me>, Daniel Wagner <dwagner@suse.de>,
Wen Xiong <wenxiong@us.ibm.com>, Hannes Reinecke <hare@suse.de>,
Ming Lei <ming.lei@redhat.com>
Subject: [PATCH V5 0/3] blk-mq: fix blk_mq_alloc_request_hctx
Date: Wed, 21 Jul 2021 17:17:20 +0800 [thread overview]
Message-ID: <20210721091723.1152456-1-ming.lei@redhat.com> (raw)
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.
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):
driver core: 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 | 1 +
block/blk-mq-rdma.c | 3 +++
block/blk-mq-virtio.c | 1 +
block/blk-mq.c | 27 ++++++++++++++++----------
block/blk-mq.h | 8 ++++++++
drivers/base/core.c | 15 ++++++++++++++
drivers/scsi/hisi_sas/hisi_sas_v2_hw.c | 1 +
include/linux/blk-mq.h | 3 ++-
include/linux/device.h | 2 ++
9 files changed, 50 insertions(+), 11 deletions(-)
--
2.31.1
next reply other threads:[~2021-07-21 9:27 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-21 9:17 Ming Lei [this message]
2021-07-21 9:17 ` [PATCH V5 1/3] driver core: add device_has_managed_msi_irq Ming Lei
2021-07-21 13:48 ` Greg Kroah-Hartman
2021-07-21 14:36 ` Christoph Hellwig
2021-07-21 9:17 ` [PATCH V5 2/3] blk-mq: mark if one queue map uses managed irq Ming Lei
2021-07-21 14:37 ` Christoph Hellwig
2021-07-22 1:24 ` Ming Lei
2021-07-21 18:53 ` John Garry
2021-07-22 1:22 ` Ming Lei
2021-07-21 9:17 ` [PATCH V5 3/3] blk-mq: don't deactivate hctx if managed irq isn't used Ming Lei
2021-07-21 14:37 ` Christoph Hellwig
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