From: Christoph Hellwig <hch@lst.de>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: Keith Busch <kbusch@kernel.org>,
Anton Eidelman <anton@lightbitslabs.com>,
Christoph Hellwig <hch@lst.de>,
linux-nvme <linux-nvme@lists.infradead.org>,
Hannes Reinecke <hare@suse.de>
Subject: Re: nvme deadlock with ANA
Date: Thu, 2 Apr 2020 17:18:54 +0200 [thread overview]
Message-ID: <20200402151854.GA11784@lst.de> (raw)
In-Reply-To: <5e38c566-3f26-288d-1004-161d1084b468@grimberg.me>
On Wed, Mar 25, 2020 at 11:23:50PM -0700, Sagi Grimberg wrote:
> Hey,
>
> I want to consult with you guys on a deadlock condition I'm able to
> hit with a test that incorporate controller reconnect, ana updates
> and live I/O with timeouts.
>
> This is true for NVMe/TCP, but can also happen in rdma or pci drivers as
> well.
>
> The deadlock combines 4 flows in parallel:
> - ns scanning (triggered from reconnect)
> - request timeout
> - ANA update (triggered from reconnect)
> - FS I/O coming into the mpath device
>
> (1) ns scanning triggers disk revalidation -> update disk info ->
> freeze queue -> but blocked, why?
What does -> but blocked mean?
>
>
>
> (2) timeout handler reference the g_usage_counter - > but blocks in
> the timeout handler, why?
The timeout handler obviously needs to keep the queue alive while
running. We could think of doing a try_get, though?
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next prev parent reply other threads:[~2020-04-02 15:19 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-26 6:23 nvme deadlock with ANA Sagi Grimberg
2020-03-26 6:29 ` Sagi Grimberg
2020-04-02 7:09 ` Sagi Grimberg
2020-04-02 15:18 ` Christoph Hellwig [this message]
2020-04-02 15:24 ` Sagi Grimberg
2020-04-02 15:30 ` Hannes Reinecke
2020-04-02 15:38 ` Sagi Grimberg
2020-04-02 17:22 ` James Smart
2020-04-02 16:00 ` Keith Busch
2020-04-02 16:08 ` Sagi Grimberg
2020-04-02 16:12 ` Hannes Reinecke
2020-04-02 16:18 ` Sagi Grimberg
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