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Date:   Thu, 18 Jun 2020 10:39:40 +0200
From:   Javier =?utf-8?B?R29uesOhbGV6?= <javier@javigon.com>
To:     Matias =?utf-8?B?QmrDuHJsaW5n?= <mb@lightnvm.io>
Cc:     Kanchan Joshi <joshi.k@samsung.com>, axboe@kernel.dk,
        viro@zeniv.linux.org.uk, bcrl@kvack.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-aio@kvack.org, io-uring@vger.kernel.org,
        linux-block@vger.kernel.org, selvakuma.s1@samsung.com,
        nj.shetty@samsung.com, Damien Le Moal <Damien.LeMoal@wdc.com>,
        Keith Busch <keith.busch@wdc.com>,
        Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 0/3] zone-append support in aio and io-uring
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On 18.06.2020 10:32, Matias Bjørling wrote:
>On 18/06/2020 10.27, Javier González wrote:
>>On 18.06.2020 10:04, Matias Bjørling wrote:
>>>On 17/06/2020 19.23, Kanchan Joshi wrote:
>>>>This patchset enables issuing zone-append using aio and io-uring 
>>>>direct-io interface.
>>>>
>>>>For aio, this introduces opcode IOCB_CMD_ZONE_APPEND. 
>>>>Application uses start LBA
>>>>of the zone to issue append. On completion 'res2' field is used 
>>>>to return
>>>>zone-relative offset.
>>>>
>>>>For io-uring, this introduces three opcodes: 
>>>>IORING_OP_ZONE_APPEND/APPENDV/APPENDV_FIXED.
>>>>Since io_uring does not have aio-like res2, cqe->flags are 
>>>>repurposed to return zone-relative offset
>>>
>>>Please provide a pointers to applications that are updated and 
>>>ready to take advantage of zone append.
>>
>>Good point. We are posting a RFC with fio support for append. We wanted
>>to start the conversation here before.
>>
>>We can post a fork for improve the reviews in V2.
>
>Christoph's response points that it is not exactly clear how this 
>matches with the POSIX API.

Yes. We will address this.
>
>fio support is great - but I was thinking along the lines of 
>applications that not only benchmark performance. fio should be part 
>of the supported applications, but should not be the sole reason the 
>API is added.

Agree. It is a process with different steps. We definitely want to have
the right kernel interface before pushing any changes to libraries and /
or applications. These will come as the interface becomes more stable.

To start with xNVMe will be leveraging this new path. A number of
customers are leveraging the xNVMe API for their applications already.

Thanks,
Javier