From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Martin K. Petersen" Subject: Re: [PATCH v2] Support for write stream IDs Date: Tue, 05 May 2015 17:39:36 -0400 Message-ID: References: <1430856181-19568-1-git-send-email-axboe@fb.com> <55493097.6040007@fb.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Jeff Moyer , , , , To: Jens Axboe Return-path: In-Reply-To: <55493097.6040007@fb.com> (Jens Axboe's message of "Tue, 5 May 2015 15:05:27 -0600") Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org >>>>> "Jens" == Jens Axboe writes: Jens> The kernel patches deal only with ensuring that the stream Jens> information gets passed down. If the device requires explicit Jens> stream open/close actions, then that needs to be handled on the Jens> side. Well, I'm deeply concerned about that "on the side" thing. I know you're trying to make a shortcut by only caring about the transport mechanism and deferring the whole programming model piece of the equation. I think the latter is hugely important, though. And if we defer the programming model question then the chances are that we'll be stuck with something lame in the standards. The storage vendors appear to think that a handful of stream ids ought to be enough for anybody. And that IDs are a scarce resource that they'll hand out for a limited time if you ask nicely. I think that model is completely broken and also of limited use for non-NVM types of storage. Sadly it's the same people who are driving the NVMe and SCSI proposals so they are similar. My concern is that by adding just enough plumbing to the kernel to allow the current standards proposals to work then we'll be stuck with them forever. And I think that would be very unfortunate. -- Martin K. Petersen Oracle Linux Engineering