From: Christoph Hellwig <hch@lst.de>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
Chaitanya Kulkarni <chaitanyak@nvidia.com>,
Sagi Grimberg <sagi@grimberg.me>, Keith Busch <kbusch@kernel.org>,
Bart Van Assche <bvanassche@acm.org>
Subject: Re: [PATCH V3 4/6] nvme: paring quiesce/unquiesce
Date: Tue, 12 Oct 2021 12:36:20 +0200 [thread overview]
Message-ID: <20211012103620.GB29640@lst.de> (raw)
In-Reply-To: <20211009034713.1489183-5-ming.lei@redhat.com>
On Sat, Oct 09, 2021 at 11:47:11AM +0800, Ming Lei wrote:
> The current blk_mq_quiesce_queue() and blk_mq_unquiesce_queue() always
> stops and starts the queue unconditionally. And there can be concurrent
> quiesce/unquiesce coming from different unrelated code paths, so
> unquiesce may come unexpectedly and start queue too early.
>
> Prepare for supporting concurrent quiesce/unquiesce from multiple
> contexts, so that we can address the above issue.
>
> NVMe has very complicated quiesce/unquiesce use pattern, add one atomic
> bit for makeiing sure that blk-mq quiece/unquiesce is always called in
> pair.
Can you explain the need for these bits a little more? If they are
unbalanced we should probably fix the root cause.
What issues did you see?
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next prev parent reply other threads:[~2021-10-12 10:36 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-09 3:47 [PATCH V3 0/6] blk-mq: support concurrent queue quiescing Ming Lei
2021-10-09 3:47 ` [PATCH V3 1/6] nvme: add APIs for stopping/starting admin queue Ming Lei
2021-10-09 3:47 ` [PATCH V3 2/6] nvme: apply nvme API to quiesce/unquiesce " Ming Lei
2021-10-09 3:47 ` [PATCH V3 3/6] nvme: prepare for pairing quiescing and unquiescing Ming Lei
2021-10-09 3:47 ` [PATCH V3 4/6] nvme: paring quiesce/unquiesce Ming Lei
2021-10-12 10:36 ` Christoph Hellwig [this message]
2021-10-12 15:01 ` Ming Lei
2021-10-12 15:07 ` Christoph Hellwig
2021-10-12 15:17 ` Ming Lei
2021-10-13 12:23 ` Sagi Grimberg
2021-10-09 3:47 ` [PATCH V3 5/6] nvme: loop: clear NVME_CTRL_ADMIN_Q_STOPPED after admin queue is reallocated Ming Lei
2021-10-09 3:47 ` [PATCH V3 6/6] blk-mq: support concurrent queue quiesce/unquiesce Ming Lei
2021-10-12 10:30 ` Christoph Hellwig
2021-10-12 15:06 ` Ming Lei
2021-10-12 15:08 ` Christoph Hellwig
2021-10-12 15:13 ` Ming Lei
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