From: Keith Busch <kbusch@kernel.org>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: Ming Lei <ming.lei@redhat.com>, Christoph Hellwig <hch@lst.de>,
linux-nvme@lists.infradead.org, Yi Zhang <yi.zhang@redhat.com>,
linux-block@vger.kernel.org, Chunguang Xu <brookxu.cn@gmail.com>
Subject: Re: [PATCH 2/2] nvme: don't freeze/unfreeze queues from different contexts
Date: Tue, 13 Jun 2023 16:43:34 -0600 [thread overview]
Message-ID: <ZIjxFhaV5nikG71S@kbusch-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <4c40b502-4309-d601-d8bc-18042c3f490c@grimberg.me>
On Tue, Jun 13, 2023 at 11:34:05PM +0300, Sagi Grimberg wrote:
>
> > > And this way is correct because quiesce is enough for driver to handle
> > > error recovery. The only difference is where to wait during error recovery.
> > > With this way, IO is just queued in block layer queue instead of
> > > __bio_queue_enter(), finally waiting for completion is done in upper
> > > layer. Either way, IO can't move on during error recovery.
> >
> > The point was to contain the fallout from modifying the hctx mappings.
> > If you allow IO to queue in the blk-mq layer while a reset is in
> > progress, they may be entering a context that won't be as expected on
> > the other side of the reset.
>
> That still happens to *some* commands though right?
That is possible only for commands that were already dispatched and
subsequently failed with retry disposition. At the point of reset today,
nothing new enters a queue till we know what the mapping looks like.
next prev parent reply other threads:[~2023-06-13 22:43 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-13 0:58 [PATCH 0/2] nvme: fix two kinds of IO hang from removing NSs Ming Lei
2023-06-13 0:58 ` [PATCH 1/2] nvme: core: unquiesce io queues when removing namespaces Ming Lei
2023-06-13 13:16 ` Sagi Grimberg
2023-06-13 0:58 ` [PATCH 2/2] nvme: don't freeze/unfreeze queues from different contexts Ming Lei
2023-06-13 13:13 ` Sagi Grimberg
2023-06-13 13:20 ` Ming Lei
2023-06-13 13:26 ` Sagi Grimberg
2023-06-13 14:41 ` Keith Busch
2023-06-13 20:34 ` Sagi Grimberg
2023-06-13 22:43 ` Keith Busch [this message]
2023-06-14 0:38 ` Ming Lei
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