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[5.186.121.195]) by smtp.gmail.com with ESMTPSA id j17-20020a05600c191100b00389a1a68b95sm4801873wmq.27.2022.03.15.06.26.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Mar 2022 06:26:11 -0700 (PDT) Date: Tue, 15 Mar 2022 14:26:11 +0100 From: Javier =?utf-8?B?R29uesOhbGV6?= To: Matias =?utf-8?B?QmrDuHJsaW5n?= Cc: Damien Le Moal , Christoph Hellwig , Luis Chamberlain , Keith Busch , Pankaj Raghav , Adam Manzanares , "jiangbo.365@bytedance.com" , kanchan Joshi , Jens Axboe , Sagi Grimberg , Pankaj Raghav , Kanchan Joshi , "linux-block@vger.kernel.org" , "linux-nvme@lists.infradead.org" Subject: Re: [PATCH 0/6] power_of_2 emulation support for NVMe ZNS devices Message-ID: <20220315132611.g5ert4tzuxgi7qd5@unifi> References: <20220314073537.GA4204@lst.de> <05a1fde2-12bd-1059-6177-2291307dbd8d@opensource.wdc.com> <20220314104938.hv26bf5vah4x32c2@ArmHalley.local> <20220314195551.sbwkksv33ylhlyx2@ArmHalley.local> <20220315130501.q7fjpqzutadadfu3@ArmHalley.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220315_062616_859631_5A861E8A X-CRM114-Status: GOOD ( 24.81 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 15.03.2022 13:14, Matias Bjørling wrote: >> > >> >All that said - if there are people willing to do the work and it doesn't have a >> negative impact on performance, code quality, maintenance complexity, etc. >> then there isn't anything saying support can't be added - but it does seem like >> it’s a lot of work, for little overall benefits to applications and the host users. >> >> Exactly. >> >> Patches in the block layer are trivial. This is running in production loads without >> issues. I have tried to highlight the benefits in previous benefits and I believe >> you understand them. >> >> Support for ZoneFS seems easy too. We have an early POC for btrfs and it >> seems it can be done. We sign up for these 2. >> >> As for F2FS and dm-zoned, I do not think these are targets at the moment. If >> this is the path we follow, these will bail out at mkfs time. >> >> If we can agree on the above, I believe we can start with the code that enables >> the existing customers and build support for butrfs and ZoneFS in the next few >> months. >> >> What do you think? > >I would suggest to do it in a single shot, i.e., a single patchset, which enables all the internal users in the kernel (including f2fs and others). That way end-users do not have to worry about the difference of PO2/NPO2 zones and it'll help reduce the burden on long-term maintenance. Thanks for the suggestion Matias. Happy to see that you are open to support this. I understand why a patchseries fixing all is attracgive, but we do not see a usage for ZNS in F2FS, as it is a mobile file-system. As other interfaces arrive, this work will become natural. ZoneFS and butrfs are good targets for ZNS and these we can do. I would still do the work in phases to make sure we have enough early feedback from the community. Since this thread has been very active, I will wait some time for Christoph and others to catch up before we start sending code.