From: Sagi Grimberg <sagi@grimberg.me>
To: Hannes Reinecke <hare@suse.de>, Keith Busch <keith.busch@wdc.com>
Cc: linux-nvme@lists.infradead.org,
James Smart <james.smart@broadcom.com>,
Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
John Meneghini <john.meneghini@netapp.com>
Subject: Re: [PATCH RFC] nvme/fc: sq flow control
Date: Tue, 25 Feb 2020 16:38:17 -0800 [thread overview]
Message-ID: <5cddf6e5-e92b-fa36-1ad5-e2cda1175150@grimberg.me> (raw)
In-Reply-To: <3611ba73-0d9d-a7ed-356b-bb856711a27c@suse.de>
>>> As per NVMe-oF spec sq flow control is actually mandatory, and we should
>>> be implementing it to avoid the controller to return a fatal status
>>> error, and try to play nicely with controllers using sq flow control
>>> to implement QoS.
>>
>> Why is your target setting SQ flow control disable in the discovery
>> log entry treq field? We are not supposed to do it if the NVM subsystem
>> doesn't support it.
> Did I say this? I wasn't aware that I did imply that in any way.
> I'm just using the flag to figure out if sq flow control is disabled or
> not.
OK, I read it backwards.
So in essence blk-mq will just keep sending until sq_head is
incremented.. How often does that happen typically?
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next prev parent reply other threads:[~2020-02-26 0:38 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-25 23:59 [PATCH RFC] nvme/fc: sq flow control Hannes Reinecke
2020-02-26 0:08 ` Sagi Grimberg
2020-02-26 0:14 ` Hannes Reinecke
2020-02-26 0:38 ` Sagi Grimberg [this message]
2020-02-27 11:27 ` Hannes Reinecke
2020-02-26 10:44 ` Martin Wilck
2020-02-26 15:47 ` Hannes Reinecke
2020-02-26 23:45 ` Sagi Grimberg
2020-02-27 1:46 ` James Smart
2020-02-27 3:52 ` Sagi Grimberg
2020-02-27 21:46 ` Meneghini, John
2020-02-28 16:35 ` James Smart
2020-02-28 10:39 ` Hannes Reinecke
2020-03-09 21:59 ` James Smart
2020-03-10 6:55 ` Hannes Reinecke
2020-03-10 16:44 ` James Smart
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