From: Sagi Grimberg <sagi@grimberg.me>
To: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <kbusch@kernel.org>,
James Smart <james.smart@broadcom.com>,
linux-nvme@lists.infradead.org
Subject: Re: [PATCH 1/3] nvme-fabrics: only reserve a single tag
Date: Fri, 5 Mar 2021 12:51:15 -0800 [thread overview]
Message-ID: <49d65274-002c-237b-163e-c3d482644a80@grimberg.me> (raw)
In-Reply-To: <20210303125304.1200789-2-hch@lst.de>
> Fabrics drivers currently reserve two tags on the admin queue. But
> given that the connect command is only run on a freshly created queue
> or after all commands have been force aborted we only need to reserve
> a single tag.
Umm, I think this would be an issue for non-mpath fabrics devices...
When we teardown the controller, we iterate over all tags
and cancel them, however for non-mpath devices these actually
stick around until they exhaust the retrys counter (with the
hope that the controller will reconnect again) unlike the mpath
case where the requests are failed-over.
Now if the admin queue is absolutely full during a reset, we won't
have a keep-alive command.
One possible solution is to make sure that
nvme_decide_disposition to complete a request for admin
commands. However note that this means that admin commands
would fail immediately when the controller resets, which is
a regression from the existing behavior and we may piss off
users with that...
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next prev parent reply other threads:[~2021-03-05 20:51 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-03 12:53 reserved tag allocation fixups Christoph Hellwig
2021-03-03 12:53 ` [PATCH 1/3] nvme-fabrics: only reserve a single tag Christoph Hellwig
2021-03-03 21:03 ` Daniel Wagner
2021-03-03 21:26 ` Chaitanya Kulkarni
2021-03-04 7:02 ` Hannes Reinecke
2021-03-05 20:51 ` Sagi Grimberg [this message]
2021-03-06 7:09 ` Christoph Hellwig
2021-03-15 17:12 ` Sagi Grimberg
2021-03-03 12:53 ` [PATCH 2/3] nvme: merge nvme_keep_alive into nvme_keep_alive_work Christoph Hellwig
2021-03-03 21:01 ` Daniel Wagner
2021-03-03 21:24 ` Chaitanya Kulkarni
2021-03-03 21:53 ` Chaitanya Kulkarni
2021-03-04 7:02 ` Hannes Reinecke
2021-03-15 17:13 ` Sagi Grimberg
2021-03-03 12:53 ` [PATCH 3/3] nvme: allocate the keep alive request using BLK_MQ_REQ_NOWAIT Christoph Hellwig
2021-03-03 21:00 ` Daniel Wagner
2021-03-03 21:22 ` Chaitanya Kulkarni
2021-03-04 7:03 ` Hannes Reinecke
2021-03-15 17:13 ` Sagi Grimberg
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