Messages in this thread | | | From | Javier Gonzalez <> | Date | Thu, 20 Aug 2020 08:37:19 +0200 | Subject | Re: [PATCH 2/2] nvme: add emulation for zone-append |
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On 19.08.2020 13:25, Jens Axboe wrote: >On 8/19/20 12:11 PM, David Fugate wrote: >> On Tue, 2020-08-18 at 07:12 +0000, Christoph Hellwig wrote: >>> On Tue, Aug 18, 2020 at 10:59:36AM +0530, Kanchan Joshi wrote: >>>> If drive does not support zone-append natively, enable emulation >>>> using >>>> regular write. >>>> Make emulated zone-append cmd write-lock the zone, preventing >>>> concurrent append/write on the same zone. >>> >>> I really don't think we should add this. ZNS and the Linux support >>> were all designed with Zone Append in mind, and then your company did >>> the nastiest possible move violating the normal NVMe procedures to >>> make >>> it optional. But that doesn't change the fact the Linux should keep >>> requiring it, especially with the amount of code added here and how >>> it >>> hooks in the fast path. >> >> Intel does not support making *optional* NVMe spec features *required* >> by the NVMe driver. > >It's not required, the driver will function quite fine without it. If you >want to use ZNS it's required. The Linux driver thankfully doesn't need >any vendor to sign off on what it can or cannot do, or what features >are acceptable. > >> It's forgivable WDC's accepted contribution didn't work with other >> vendors' devices choosing not to implement the optional Zone Append, >> but it's not OK to reject contributions remedying this. Provided >> there's no glaring technical issues, Samsung's contribution should be >> accepted to maintain both spec compliance as well as vendor neutrality. > >It's *always* ok to reject contributions, if those contributions cause >maintainability issues, unacceptable slowdowns, or whatever other issue >that the maintainers of said driver don't want to deal with. Any >contribution should be judged on merit, not based on political decisions >or opinions. Obviously this thread reeks of it. >
I'll reply here, where the discussion diverges from this particular patch.
We will stop pushing for this emulation. We have a couple of SSDs where we disabled Append, we implemented support for them, and we wanted to push the changes upstream. That's it. This is no politics not a conspiracy against the current ZNS spec. We spent a lot of time working on this spec and are actually doing a fair amount of work to support Append other places in the stack. In any case, the fuzz stops here.
Javier
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