From: Jens Axboe <axboe@kernel.dk>
To: Christoph Hellwig <hch@lst.de>, Ming Lei <ming.lei@redhat.com>
Cc: linux-block@vger.kernel.org, John Garry <john.garry@huawei.com>,
Bart Van Assche <bvanassche@acm.org>,
Hannes Reinecke <hare@suse.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: blk-mq: improvement CPU hotplug (simplified version) v4
Date: Fri, 29 May 2020 10:23:49 -0600 [thread overview]
Message-ID: <9a790a4d-e61d-52c5-8ef7-70a509ee6541@kernel.dk> (raw)
In-Reply-To: <20200529135315.199230-1-hch@lst.de>
On 5/29/20 7:53 AM, Christoph Hellwig wrote:
> 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.
Applied, thanks.
--
Jens Axboe
next prev parent reply other threads:[~2020-05-29 16:23 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-29 13:53 blk-mq: improvement CPU hotplug (simplified version) v4 Christoph Hellwig
2020-05-29 13:53 ` [PATCH 1/8] blk-mq: remove the bio argument to ->prepare_request Christoph Hellwig
2020-05-29 13:53 ` [PATCH 2/8] blk-mq: simplify the blk_mq_get_request calling convention Christoph Hellwig
2020-05-29 13:53 ` [PATCH 3/8] blk-mq: move more request initialization to blk_mq_rq_ctx_init Christoph Hellwig
2020-05-29 13:53 ` [PATCH 4/8] blk-mq: rename BLK_MQ_TAG_FAIL to BLK_MQ_NO_TAG Christoph Hellwig
2020-05-29 13:53 ` [PATCH 5/8] blk-mq: use BLK_MQ_NO_TAG in more places Christoph Hellwig
2020-05-29 13:53 ` [PATCH 6/8] blk-mq: open code __blk_mq_alloc_request in blk_mq_alloc_request_hctx Christoph Hellwig
2020-05-29 13:53 ` [PATCH 7/8] blk-mq: add blk_mq_all_tag_iter Christoph Hellwig
2020-05-29 16:14 ` Bart Van Assche
2020-05-29 13:53 ` [PATCH 8/8] blk-mq: drain I/O when all CPUs in a hctx are offline Christoph Hellwig
2020-05-29 14:34 ` Hannes Reinecke
2020-05-29 14:41 ` Daniel Wagner
2020-05-29 16:23 ` Jens Axboe [this message]
-- strict thread matches above, loose matches on Subject: below --
2020-05-27 18:06 blk-mq: improvement CPU hotplug (simplified version) v4 Christoph Hellwig
2020-05-27 20:07 ` Bart Van Assche
2020-05-27 20:31 ` John Garry
2020-05-29 13:26 ` Christoph Hellwig
2020-05-28 8:29 ` John Garry
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