From: daniel.verkamp@intel.com (Verkamp, Daniel)
Subject: [PATCH 2/2] nvme-rdma: sqsize/hsqsize/hrqsize is 0-based val
Date: Mon, 8 Aug 2016 16:08:22 +0000 [thread overview]
Message-ID: <1470672500.40000.20.camel@intel.com> (raw)
In-Reply-To: <8bca04d5-8793-5bc3-9a18-4a7f66af40cc@grimberg.me>
On Sun, 2016-08-07@10:29 +0300, Sagi Grimberg wrote:
> >
> > Per NVMe-over-Fabrics 1.0 spec, sqsize is represented as
> > a 0-based value.
>
> Did we really decide that? The spec actually explicitly says
> that a 0 sqsize will be failed:
>
> "If the size is 0h or larger than the controller supports, then a
> status value of Connect Invalid Parameters shall be returned."
>
> And then it says: "This is a 0?s based value"
>
> Confusing....
I think 0 is disallowed because that would mean the queue size is 1, and
NVMe requires at least a queue size of 2 to be useful at all (one slot
has to be empty to avoid confusion between queue full and queue empty
cases).
-- Daniel
prev parent reply other threads:[~2016-08-08 16:08 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-06 0:54 [PATCH 0/2] nvme-fabrics: sqsize bug fixes Jay Freyensee
2016-08-06 0:54 ` [PATCH 1/2] nvme-rdma: tell fabrics layer admin queue depth Jay Freyensee
2016-08-07 7:20 ` Sagi Grimberg
2016-08-08 7:05 ` Christoph Hellwig
2016-08-08 16:11 ` J Freyensee
2016-08-06 0:54 ` [PATCH 2/2] nvme-rdma: sqsize/hsqsize/hrqsize is 0-based val Jay Freyensee
2016-08-07 7:29 ` Sagi Grimberg
2016-08-08 7:06 ` Christoph Hellwig
2016-08-08 16:30 ` Verkamp, Daniel
[not found] ` <9A947B1F6D0FF74CB5D6ACFF43B473F3A3A45C75@ORSMSX112.amr.corp.intel.com>
2016-08-08 18:39 ` J Freyensee
2016-08-08 16:08 ` Verkamp, Daniel [this message]
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