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From: Christoph Hellwig <hch@lst.de>
To: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	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 17:07:41 +0200	[thread overview]
Message-ID: <20211012150741.GA20571@lst.de> (raw)
In-Reply-To: <YWWjXN3GEzypVFZ/@T590>

On Tue, Oct 12, 2021 at 11:01:48PM +0800, Ming Lei wrote:
> There are lots of unbalanced usage in nvme, such as
> 
> 1) nvme pci:
> 
> - nvme_dev_disable() can be called more than one times before starting
> reset, so multiple nvme_stop_queues() vs. single nvme_start_queues().
> 
> 2) Forcibly unquiesce queues in nvme_kill_queues() even though queues
> are never quiesced, and similar usage can be seen in tcp/fc/rdma too
> 
> Once the quiesce and unquiesce are run from difference context, it becomes
> not easy to audit if the two is done in pair.

Yes, but I'm not sure a magic flag is really the solution here.
I think we need to work on our state machine here so that this is less
of a mess.

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	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 17:07:41 +0200	[thread overview]
Message-ID: <20211012150741.GA20571@lst.de> (raw)
In-Reply-To: <YWWjXN3GEzypVFZ/@T590>

On Tue, Oct 12, 2021 at 11:01:48PM +0800, Ming Lei wrote:
> There are lots of unbalanced usage in nvme, such as
> 
> 1) nvme pci:
> 
> - nvme_dev_disable() can be called more than one times before starting
> reset, so multiple nvme_stop_queues() vs. single nvme_start_queues().
> 
> 2) Forcibly unquiesce queues in nvme_kill_queues() even though queues
> are never quiesced, and similar usage can be seen in tcp/fc/rdma too
> 
> Once the quiesce and unquiesce are run from difference context, it becomes
> not easy to audit if the two is done in pair.

Yes, but I'm not sure a magic flag is really the solution here.
I think we need to work on our state machine here so that this is less
of a mess.

_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

  reply	other threads:[~2021-10-12 15:07 UTC|newest]

Thread overview: 32+ 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 ` 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   ` 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   ` 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   ` Ming Lei
2021-10-09  3:47 ` [PATCH V3 4/6] nvme: paring quiesce/unquiesce Ming Lei
2021-10-09  3:47   ` Ming Lei
2021-10-12 10:36   ` Christoph Hellwig
2021-10-12 10:36     ` Christoph Hellwig
2021-10-12 15:01     ` Ming Lei
2021-10-12 15:01       ` Ming Lei
2021-10-12 15:07       ` Christoph Hellwig [this message]
2021-10-12 15:07         ` Christoph Hellwig
2021-10-12 15:17         ` Ming Lei
2021-10-12 15:17           ` Ming Lei
2021-10-13 12:23           ` Sagi Grimberg
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   ` Ming Lei
2021-10-09  3:47 ` [PATCH V3 6/6] blk-mq: support concurrent queue quiesce/unquiesce Ming Lei
2021-10-09  3:47   ` Ming Lei
2021-10-12 10:30   ` Christoph Hellwig
2021-10-12 10:30     ` Christoph Hellwig
2021-10-12 15:06     ` Ming Lei
2021-10-12 15:06       ` Ming Lei
2021-10-12 15:08       ` Christoph Hellwig
2021-10-12 15:08         ` Christoph Hellwig
2021-10-12 15:13         ` Ming Lei
2021-10-12 15:13           ` Ming Lei

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