From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH 11/11] nvme: add support for streams and directives To: Christoph Hellwig Cc: linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, adilger@dilger.ca, martin.petersen@oracle.com References: <1497633883-21230-12-git-send-email-axboe@kernel.dk> <20170616180942.GD27996@infradead.org> <9811b106-a954-2481-8a66-afb25df76812@kernel.dk> <20170617122106.GB8320@infradead.org> <1ede2083-69db-a86f-8e32-43ca293e9c8e@kernel.dk> <20170617150303.GA15290@infradead.org> <20170619062557.GA2311@infradead.org> <03b922f9-677e-9618-663e-09f023977fa8@kernel.dk> <0e920111-7846-f7f6-2288-e375f6a43843@kernel.dk> <20170619185314.GA32047@infradead.org> From: Jens Axboe Message-ID: <5ffacae2-ca79-ef3c-8af8-8803ea17fa97@kernel.dk> Date: Mon, 19 Jun 2017 13:03:06 -0600 MIME-Version: 1.0 In-Reply-To: <20170619185314.GA32047@infradead.org> Content-Type: text/plain; charset=utf-8 List-ID: On 06/19/2017 12:53 PM, Christoph Hellwig wrote: > On Mon, Jun 19, 2017 at 08:53:08AM -0600, Jens Axboe wrote: >> Looking at it a bit more closely - there's a difference between >> assigning X number of streams (allocating) for use by the subsystem or >> per-ns, and having to manually open them. So I don't necessarily think >> there's a problem here, neither for us or on the device. > > As far as I can tell the allocate resource is only supposed to be > for an individual namespace: > > Section 9.3: > > "Stream resources may be allocated for the exclusive use of a specified > namespace associated with a particular Host Identifier using the Allocate > Resources operation. Stream resources that are not allocated for the > exclusive use of any namespace are available NVM subsystem stream > resources as reported in NVM Subsystem Streams Available (NSSA) and may > be used by any namespace that has the Streams Directive enabled and has > not been allocated exclusive stream resources in response to an > Allocate Resources operation" > > Section 9.3.1.3: > > "The Allocate Resources operation indicates the number of streams that the host requests for the exclusive use of the specified namespace." > > I think this is pretty clear, but if not it would be good if you could > bring it into the working group so that we can clarify it further. I'll wait until I hear back from the manufacturer, it could just be an oversight on their end. But yes, the language should be clarified. >> Awaiting clarification from the vendor what their position/view of this >> is. Reading the spec, I do agree that it leans towards only needing >> allocation for a specific name space, but it doesn't explicitly say that >> you can use any of the available streams, without allocation, if they >> haven't been assigned to a specific name space. I would interpret it >> that way, though. > > Let's get some text into an ECN either way to clarify it.. Thanks -- Jens Axboe