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Petersen" , Kanchan Joshi , "hare@suse.de" , "sagi@grimberg.me" , "brauner@kernel.org" , "viro@zeniv.linux.org.uk" , "jack@suse.cz" , "jaegeuk@kernel.org" , "bcrl@kvack.org" , "dhowells@redhat.com" , "bvanassche@acm.org" , "asml.silence@gmail.com" , "linux-nvme@lists.infradead.org" , "linux-fsdevel@vger.kernel.org" , "io-uring@vger.kernel.org" , "linux-block@vger.kernel.org" , "linux-aio@kvack.org" , "gost.dev@samsung.com" , "vishak.g@samsung.com" Subject: RE: [PATCH v7 0/3] FDP and per-io hints Thread-Topic: [PATCH v7 0/3] FDP and per-io hints Thread-Index: AQHbG7xJFahlOOmkRUWBz3B/P2gFpLKBuCIAgAQCOYCAABtsUP///IcAgAAiAcCAACIYAIABC7FQ Date: Tue, 15 Oct 2024 03:07:57 +0000 Message-ID: In-Reply-To: <20241014115052.GA32302@lst.de> Accept-Language: en-US, en-GB Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Brightmail-Tracker: H4sIAAAAAAAAA02SfUxTVxjGOfdebi8dxUtReoLbiE3IEmEFDI7jImxZxN1FZSbbJCMqNnJT iKWQFizzY3QwFAFlq4KzMKFOi4WArjL5xlCGDEUNqeKKVmSUyYqDQl0WLcIotyz893s/nvO8 75tD4cJjZAiVrshmlQqpXEzyies3X9599/vHAlnUObc/qqq7DlC9rYxExfNNBJrsmQWowvkS R1P5bgJ1XNBiyFjfi6GpwrsEqjxbgCH7FR2OtOYhgM5U5APUORyOOjr7CVRtGOeh2r55DDVO ThPo3us+3w+DGMv9bUyrzsZj7j35mWAsd3IYU90JkjHNannMtYt5TLtVQzIz48MEM931gGQG an5dzN8+zLhMbzMm+9/YzoBk/uZUVp5+kFVGxu/jpw06Ps9yr8otbCnjaUC9fzHwoyAdA38f 7eUVAz4lpC8DmN/Z4MsFLwAsnzCRXOAC0Nr1kLcscdlmcK5QC+DVljnf/7smDBpvMACg02on PBIhbQTw35lcD5N0JKxrvgU8vJoWw3HHHeAR4PQQD3aXDmCeQhAdBQsudnmbouGUQe/lZKgx ji8xQYfBVlMp6WEBnQAbftLiHvajI+B5W+MSA/ot+Ifx1dLcOC2Cw/ZqjNshEF6o7MA5Dobz baMkx1Hwl0tdBMfr4KnqaYLTRsCa9lmS43Bo0E/inG8g7D/nWZK/2N/Ph9dKGrxH2gLPzp33 PhoEHX1N3vybcKF1eYjDUNP/G/YdWK9bMZ9uhZ9uhZ9uhV8NIOqAiM1RZchYVbSCVUtU0gxV jkIm2Z+ZYQKLX/X2fN9sC/jRMSMxA4wCZgApXLxaoC0WyISCVOlXh1hlZooyR86qzGAtRYhF grDUUFZIy6TZ7AGWzWKVy1WM8gvRYDGDceWyFskRufrF14+cuZu/tMZuGwkP7zaQlrkbRT9Q TEy3a7f7TPYjdV6Y4Z245nb8yPE/ZfGKocyC2FfPUxKjsQT/wWP6rZ9Onf4scDRhQ8le88ba piLLITygNGRUXBl8ac1HVek7ch8bB65m/LXjRlJFXtLJHkf2lpDETfh97Z735SdHfAxtC5iP 69Q3jt6x7RL18zcCdn4c5/RTuj94DWxJESlrpcEHiaInX2Bbs8qePbPjw43J5SXv8dsSHnbG X0kTHQ0NFVkcRxv5iTrdJy61uXmsZ2Pygl5/wmq82e6jaf628OnuDf+YV3XzMPtTZ1S1duT4 xGRV5K5NTbHsmJhQpUmj1+NKlfQ/z41RExkEAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrOKsWRmVeSWpSXmKPExsVy+t/xe7oT7vCmGyzewGwxZ9U2RovVd/vZ LLr+bWGxeH34E6PFtA8/mS3eNf1msdizaBKTxcrVR5ks3rWeY7GYPb2ZyeLJ+lnMFpMOXWO0 mDKtidFi7y1tiz17T7JYzF/2lN1i+fF/TBbrXr9nsTj/9zirg7DH5SveHjtn3WX3OH9vI4vH 5bOlHptWdbJ5bPo0id1j85J6j903G9g8Pj69xeLxft9VNo8zC44AxU9Xe3zeJOex6clbpgC+ KD2bovzSklSFjPziElulaEMLIz1DSws9IxNLPUNj81grI1MlfTublNSczLLUIn27BL2Mi69C Cn7zV7Tu6GdvYFzN08XIySEhYCLx+e5H5i5GLg4hgaWMEse/XWaHSMhIbPxylRXCFpb4c62L DaLoI6PExCl/WSCcM4wSbT/WMkE4Kxklfp2dxAzSwiagL7Fq+ylGEFtEQEni6auzjCBFzAJX 2CWaFz0HSwgLGEg0L9kHVWQo8W7ZQig7SqJh5VMwm0VAVWLnph42EJtXwFVi7eJJUMfOYJF4 sHAuWIJTQEdi3t11YJsZBWQlHq38BfYEs4C4xK0n85kgnhCQWLLnPDOELSrx8vE/qOcMJLYu 3ccCYStK9M1/zwLRqyOxYPcnNghbW2LZwtfMEEcISpyc+YRlAqPULCQrZiFpmYWkZRaSlgWM LKsYRVJLi3PTc4sN9YoTc4tL89L1kvNzNzECU+C2Yz8372Cc9+qj3iFGJg7GQ4wSHMxKIryT unjThXhTEiurUovy44tKc1KLDzGaAgNmIrOUaHI+MAnnlcQbmhmYGpqYWRqYWpoZK4nzul0+ nyYkkJ5YkpqdmlqQWgTTx8TBKdXAlJEa8n/TTDN3ztr3+n8Yb2+Y7r362rfklBuuHl/57TNv Gh4yOvx9Rgnz0uKTtqLGC+rzcs+ezXm4XU6F78L0hklBxZOn35jVzGnzu7KCxXix2PX5ORsS uHM7b2w69fywczqXiqr2Md7N9yWEKo6FPEpqVGrhYSrsjsi6q1TiG/DTO0dq/U3m+HcJp5Y5 7oy6GaPxzF9zdezHRbMvzn3Q2ct7VP0/X7TfQ6vqeXP2+/MkM12qqTj082HWBmOXuJNXnq3u W3g47G9MqhK3+3oW8b9bm7zsTZYdWjLravfdp/Ylnrdz4nc9ujLX32QOn4iuneLKnVtP/fMv 2Xz34OVJqY/6mLtUa8QvLM780/rMS4mlOCPRUIu5qDgRABIoUg4KBAAA X-CMS-MailID: 20241015030800eucas1p1e2584459613eaa885539d58f9c8ec4b8 X-Msg-Generator: CA X-RootMTR: 20241010070738eucas1p2057209e5f669f37ca586ad4a619289ed X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20241010070738eucas1p2057209e5f669f37ca586ad4a619289ed References: <20241010070736.de32zgad4qmfohhe@ArmHalley.local> <20241010091333.GB9287@lst.de> <20241010115914.eokdnq2cmcvwoeis@ArmHalley.local> <20241011090224.GC4039@lst.de> <5e9f7f1c-48fd-477f-b4ba-c94e6b50b56f@kernel.dk> <20241014062125.GA21033@lst.de> <34d3ad68068f4f87bf0a61ea8fb8f217@CAMSVWEXC02.scsc.local> <20241014074708.GA22575@lst.de> <9e3792eebf7f427db7c466374972fb99@CAMSVWEXC02.scsc.local> <20241014115052.GA32302@lst.de> > On Mon, Oct 14, 2024 at 09:08:24AM +0000, Javier Gonzalez wrote: > > > Especially as it directly undermindes any file system work to actuall= y make use > of it. > > > > I do not think it does. If a FS wants to use the temperatures, then the= y > > would be able to leverage FDP besides SCSI. >=20 > What do you mean with that? This is a bit too much whitepaper vocabularl= y. >=20 > We have code in XFS that can make use of the temperature hint. But to > make them work it actually needs to do real stream separation on the > device. I.e. the file system consumes the temperature hints. The device can guarantee the stream separation without knowing the temperat= ure. > > And if we come up with a better interface later on, we can make the cha= nges > then. > > I really do not see the issue. If we were adding a temperature abstract= ion now, I > would agree with > > You that we would need to cover the use-case you mention for FSs from t= he > beginning, but this > > Is already here. Seems like a fair compromise to support current users. >=20 > Again, I think the temperature hints at the syscall level aren't all > bad. There's definitively a few things I'd like to do better in hindsigh= t, > but that's not the point. The problem is trying to turn them into > stream separation all the way down in the driver, which is fundamentally > broken. >=20 > > - How do we convince VFS folks to give us more space for hints at thi= s point? >=20 > What space from VFS folks do you need for hints? And why does it > matter? We need space in the inode to store the hint ID. Look, this feels like going in circles. All this gaslighting is what makes = it difficult to=20 push patches when you just do not like the feature. It is the 3rd time I pr= opose you=20 a way forward and you simply cannot provide any specific technical feedback= - in the=20 past email I posted several questions about the interface you seem to be ta= lking=20 about and you explicitly omit that.