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From: Christoph Hellwig <hch@lst.de>
To: John Meneghini <jmeneghi@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>, Hannes Reinecke <hare@suse.de>,
	Sagi Grimberg <sagi@grimberg.me>,
	Keith Busch <keith.busch@wdc.com>,
	linux-nvme@lists.infradead.org
Subject: Re: [PATCH] nvme-multipath: add an 'ana_groups_only' module option
Date: Thu, 10 Feb 2022 06:43:23 +0100	[thread overview]
Message-ID: <20220210054323.GA3293@lst.de> (raw)
In-Reply-To: <56fb153a-ba0e-605b-e774-885c259965a6@redhat.com>

On Wed, Feb 09, 2022 at 09:52:45PM -0500, John Meneghini wrote:
> I agree with Christoph.  I don't see the point in supporting 65536 
> namespaces across 49 ana groups or controllers. The problem here is: the 
> vendor is trying to turn NVMe into SCSI.

I'm not saying we should not support it.  We can trivially do that by
using a vmalloc buffer.  I don't think we should optimize for it, and
we certainly should not break behaviour which I think this does.

>
> Moreover, I don't understand how implementing this as a MODULE_PARM is 
> supposed to work.  If you configure this module parameter on it assumes all 
> NVMe-oF arrays connected to the host support RGO. What's really needed here 
> is some kind of protocol mechanism that will allow the host to dynamically 
> discovery if RGO is supported on a controller by controller basis.

RGO support is mandatory and has been there since the first released
ANA TP.


  reply	other threads:[~2022-02-10  5:43 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-07 10:00 [PATCH] nvme-multipath: add an 'ana_groups_only' module option Hannes Reinecke
2022-02-07 12:37 ` Sagi Grimberg
2022-02-07 13:00   ` Hannes Reinecke
2022-02-09  8:07 ` Christoph Hellwig
2022-02-09  8:49   ` Hannes Reinecke
2022-02-09 13:57     ` Christoph Hellwig
2022-02-10  2:52   ` John Meneghini
2022-02-10  5:43     ` Christoph Hellwig [this message]
2022-02-10  8:17     ` Hannes Reinecke

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