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* blk-mq: improvement CPU hotplug (simplified version) v3
@ 2020-05-20 17:06 Christoph Hellwig
  2020-05-20 17:06 ` [PATCH 1/6] blk-mq: remove the bio argument to ->prepare_request Christoph Hellwig
                   ` (6 more replies)
  0 siblings, 7 replies; 31+ messages in thread
From: Christoph Hellwig @ 2020-05-20 17:06 UTC (permalink / raw)
  Cc: linux-block, John Garry, Bart Van Assche, Hannes Reinecke,
	Thomas Gleixner

Hi all,

this series ensures I/O is quiesced before a cpu and thus the managed
interrupt handler is shut down.

This patchset tries to address the issue by the following approach:

 - before the last cpu in hctx->cpumask is going to offline, mark this
   hctx as inactive

 - disable preempt during allocating tag for request, and after tag is
   allocated, check if this hctx is inactive. If yes, give up the
   allocation and try remote allocation from online CPUs

 - before hctx becomes inactive, drain all allocated requests on this
   hctx

The guts of the changes are from Ming Lei, I just did a bunch of prep
cleanups so that they can fit in more nicely.  The series also depends
on my "avoid a few q_usage_counter roundtrips v3" series.

Thanks John Garry for running lots of tests on arm64 with this previous
version patches and co-working on investigating all kinds of issues.

A git tree is available here:

    git://git.infradead.org/users/hch/block.git blk-mq-hotplug.2

Gitweb:

    http://git.infradead.org/users/hch/block.git/shortlog/refs/heads/blk-mq-hotplug.2

Changes for v3:
  - don't disable preemption and use smp calls


^ permalink raw reply	[flat|nested] 31+ messages in thread

end of thread, other threads:[~2020-05-27  6:05 UTC | newest]

Thread overview: 31+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-20 17:06 blk-mq: improvement CPU hotplug (simplified version) v3 Christoph Hellwig
2020-05-20 17:06 ` [PATCH 1/6] blk-mq: remove the bio argument to ->prepare_request Christoph Hellwig
2020-05-20 18:16   ` Bart Van Assche
2020-05-22  9:11   ` Hannes Reinecke
2020-05-20 17:06 ` [PATCH 2/6] blk-mq: simplify the blk_mq_get_request calling convention Christoph Hellwig
2020-05-20 18:22   ` Bart Van Assche
2020-05-22  9:13   ` Hannes Reinecke
2020-05-20 17:06 ` [PATCH 3/6] blk-mq: move more request initialization to blk_mq_rq_ctx_init Christoph Hellwig
2020-05-20 20:10   ` Bart Van Assche
2020-05-20 17:06 ` [PATCH 4/6] blk-mq: open code __blk_mq_alloc_request in blk_mq_alloc_request_hctx Christoph Hellwig
2020-05-22  9:17   ` Hannes Reinecke
2020-05-20 17:06 ` [PATCH 5/6] blk-mq: add blk_mq_all_tag_iter Christoph Hellwig
2020-05-20 20:24   ` Bart Van Assche
2020-05-27  6:05     ` Christoph Hellwig
2020-05-22  9:18   ` Hannes Reinecke
2020-05-20 17:06 ` [PATCH 6/6] blk-mq: drain I/O when all CPUs in a hctx are offline Christoph Hellwig
2020-05-22  9:25   ` Hannes Reinecke
2020-05-25  9:20     ` Ming Lei
2020-05-20 21:46 ` blk-mq: improvement CPU hotplug (simplified version) v3 Bart Van Assche
2020-05-21  2:57   ` Ming Lei
2020-05-21  3:50     ` Bart Van Assche
2020-05-21  4:33       ` Ming Lei
2020-05-21 19:15         ` Bart Van Assche
2020-05-22  2:39           ` Ming Lei
2020-05-22 14:47             ` Keith Busch
2020-05-23  3:05               ` Ming Lei
2020-05-23 15:19             ` Bart Van Assche
2020-05-25  4:09               ` Ming Lei
2020-05-25 15:32                 ` Bart Van Assche
2020-05-25 16:38                   ` Keith Busch
2020-05-26  0:37                   ` Ming Lei

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