From: Hannes Reinecke <hare@suse.de>
To: Sagi Grimberg <sagi@grimberg.me>, Christoph Hellwig <hch@lst.de>
Cc: linux-nvme@lists.infradead.org, Keith Busch <keith.busch@wdc.com>
Subject: Re: [PATCH 2/2] nvme: add 'queue_if_no_path' semantics
Date: Mon, 8 Mar 2021 14:17:06 +0100 [thread overview]
Message-ID: <44affc5e-d655-aa1c-55fe-65805d66065a@suse.de> (raw)
In-Reply-To: <28830f4b-181d-2a4d-0bdd-2f63fcdbcf72@grimberg.me>
On 3/5/21 9:31 PM, Sagi Grimberg wrote:
>
>> Compare that to the 'standard', non-CMIC nvme, where with the same
>> setup MD would detach the nvme on its own:
>>
>> # cat /proc/mdstat
>> Personalities : [raid10]
>> md127 : active (auto-read-only) raid10 nvme2n1[1]
>> 4189184 blocks super 1.2 2 near-copies [2/1] [_U]
>> bitmap: 0/1 pages [0KB], 65536KB chunk
>>
>> unused devices: <none>
>> # nvme list
>> Node SN Model Namespace
>> Usage Format FW Rev
>> ---------------- --------------------
>> ---------------------------------------- ---------
>> -------------------------- ---------------- --------
>> /dev/nvme0n1 SLESNVME1 QEMU NVMe Ctrl 1
>> 17.18 GB / 17.18 GB 512 B + 0 B 1.0
>> /dev/nvme2n1 SLESNVME3 QEMU NVMe Ctrl 1
>> 4.29 GB / 4.29 GB 512 B + 0 B 1.0
>>
>> And yes, this is exactly the same setup, the only difference being the
>> CMIC setting for the NVMe device.
>
> I agree with Christoph that we should do exactly the same for all.
>
> Hannes, My understanding here is that you want the device to go away
> after the last path disappeared because it breaks md, why don't you
> want to have this also for fabrics?
>
Oh, I would _love_ to have it for fabrics per default.
If you agree with it I can resend Keiths original patch, which solves
the issue without the need for any additional settings.
> You mention that in fabrics one can manually disconnect, but why should
> the user resort to a manual disconnect?
>
> Is something else broken with this behavior? Maybe I am missing
> something here?
I'm just trying to understand why the current logic was build into
fabrics in the first place.
But if no-one remembers (or there was none) I'd happily convert to the
PCI logic.
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@suse.de +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer
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next prev parent reply other threads:[~2021-03-08 13:17 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-05 12:44 [RFC PATCHv3 0/2] nvme: queue_if_no_path functionality Hannes Reinecke
2020-10-05 12:44 ` [PATCH 1/2] nvme-mpath: delete disk after last connection Hannes Reinecke
2020-10-05 12:50 ` Christoph Hellwig
2021-03-05 20:06 ` Sagi Grimberg
2021-03-04 14:34 ` Daniel Wagner
2020-10-05 12:45 ` [PATCH 2/2] nvme: add 'queue_if_no_path' semantics Hannes Reinecke
2020-10-05 12:52 ` Christoph Hellwig
2020-10-06 5:48 ` Hannes Reinecke
2020-10-06 7:51 ` Christoph Hellwig
2020-10-06 8:07 ` Hannes Reinecke
2020-10-06 8:27 ` Christoph Hellwig
2020-10-06 8:29 ` Hannes Reinecke
2020-10-06 8:39 ` Christoph Hellwig
2020-10-06 13:30 ` Hannes Reinecke
2020-10-06 13:45 ` Hannes Reinecke
2021-03-05 20:31 ` Sagi Grimberg
2021-03-08 13:17 ` Hannes Reinecke [this message]
2021-03-15 17:21 ` Sagi Grimberg
2020-10-06 17:41 ` Keith Busch
2021-03-05 20:11 ` Sagi Grimberg
2021-03-11 12:41 ` Hannes Reinecke
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